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UNIVERSITATIS OULUENSIS MEDICA ACTA D D 1559 ACTA Mirella Ahonen-Siirtola OULU 2020 D 1559 Mirella Ahonen-Siirtola SURGICAL TREATMENT OF INCISIONAL VENTRAL HERNIA —WITH A SPECIAL REFERENCE TO LAPAROSCOPIC TECHNIQUES UNIVERSITY OF OULU GRADUATE SCHOOL; UNIVERSITY OF OULU, FACULTY OF MEDICINE; MEDICAL RESEARCH CENTER OULU; OULU UNIVERSITY HOSPITAL

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Page 1: OULU 2020 D 1559 UNIVERSITY OF OULU P.O. Box 8000 FI-90014

UNIVERSITY OF OULU P .O. Box 8000 F I -90014 UNIVERSITY OF OULU FINLAND

A C T A U N I V E R S I T A T I S O U L U E N S I S

University Lecturer Tuomo Glumoff

University Lecturer Santeri Palviainen

Postdoctoral reseracher Jani Peräntie

University Lecturer Anne Tuomisto

University Lecturer Veli-Matti Ulvinen

Planning Director Pertti Tikkanen

Professor Jari Juga

University Lecturer Anu Soikkeli

University Lecturer Santeri Palviainen

Publications Editor Kirsti Nurkkala

ISBN 978-952-62-2531-9 (Paperback)ISBN 978-952-62-2532-6 (PDF)ISSN 0355-3221 (Print)ISSN 1796-2234 (Online)

U N I V E R S I TAT I S O U L U E N S I S

MEDICA

ACTAD

D 1559

AC

TAM

irella Ahonen-Siirtola

OULU 2020

D 1559

Mirella Ahonen-Siirtola

SURGICAL TREATMENT OF INCISIONAL VENTRAL HERNIA—WITH A SPECIAL REFERENCE TO LAPAROSCOPIC TECHNIQUES

UNIVERSITY OF OULU GRADUATE SCHOOL;UNIVERSITY OF OULU,FACULTY OF MEDICINE;MEDICAL RESEARCH CENTER OULU;OULU UNIVERSITY HOSPITAL

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ACTA UNIVERS ITAT I S OULUENS I SD M e d i c a 1 5 5 9

MIRELLA AHONEN-SIIRTOLA

SURGICAL TREATMENT OF INCISIONAL VENTRAL HERNIA—with a special reference to laparoscopic techniques

Academic Dissertation to be presented with the assentof the Doctoral Training Committee of Health andBiosciences of the University of Oulu for public defencein Auditorium 1 and 2 of Oulu University Hospital(Kajaanintie 50), on 13 March 2020, at 12 noon

UNIVERSITY OF OULU, OULU 2020

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Copyright © 2020Acta Univ. Oul. D 1559, 2020

Supervised byProfessor Jyrki MäkeläDocent Tero Rautio

Reviewed byDocent Heikki HuhtinenDocent Markku Luostarinen

ISBN 978-952-62-2531-9 (Paperback)ISBN 978-952-62-2532-6 (PDF)

ISSN 0355-3221 (Printed)ISSN 1796-2234 (Online)

Cover DesignRaimo Ahonen

JUVENES PRINTTAMPERE 2020

OpponentDocent Tom Scheinin

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Ahonen-Siirtola, Mirella, Surgical treatment of incisional ventral hernia —with aspecial reference to laparoscopic techniquesUniversity of Oulu Graduate School; University of Oulu, Faculty of Medicine; MedicalResearch Center Oulu; Oulu University HospitalActa Univ. Oul. D 1559, 2020University of Oulu, P.O. Box 8000, FI-90014 University of Oulu, Finland

Abstract

An incisional hernia is a common complication following abdominal surgery. A hernia repair isrecommended for the risk of incarceration. There are several operative methods. The laparoscopictechnique is in wide use, but it is associated with a risk of enterotomy. Seroma formation is acommon postoperative finding. In the hybrid technique, adhesions can be lysed and the fascialdefect sutured through a mini-incision prior to mesh augmentation. In this thesis, we evaluate thecomplications associated with hernia repair operations, focusing on laparoscopic methods. Weexplore whether seroma formation and hernia recurrence could be diminished using the hybridmethod.

Study I was a descriptive analysis of 127 claims concerning ventral hernioplasties reported tothe Finnish Patient Insurance Centre from 2003–2010. In Study II, we analysed 818 incisionalhernia repairs, focusing on major complications. In Study III, the results of 38 laparoscopic and24 hybrid operations in cases featuring complex adhesiolysis were compared. In prospectivemulticentre Studies IV–V, 193 operations randomised to either the laparoscopic or hybridtechnique were analysed.

In retrospective Studies I–III, we found that major complications were related to undetectedenterotomies. Complex adhesions had a significant influence on major complications,enterotomies, and surgical site infections. In Studies IV–V, five enterotomies occurred inlaparoscopic operations compared to one in hybrid operations. Adhesiolysis was described clearlymore often complex in the laparoscopic group than in the hybrid group. After laparoscopy, therewere significantly more seromas when compared to the hybrid operations. After one year, nodifference in hernia recurrence was seen between the groups. Eleven (6.4%) recurrent herniaswere detected: six in the laparoscopic group and five in the hybrid group.

Laparoscopic operations carry a low complication rate, but the risk of enterotomy is stillapparent, especially in cases in which intense adhesions are present. A hybrid operation offers asafe approach to lyse adhesions by hand, and therefore the risk of enterotomy low. Seromaformation is clearly diminished after hybrid operations, but its influence on hernia recurrencerequires a longer follow-up period. Patients are pain-free following hernia repair, resulting in theirbetter quality of life.

Keywords: enterotomy, hybrid, incisional ventral hernia, laparoscopy, recurrence

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Ahonen-Siirtola, Mirella, Arpityrän kirurginen hoito – tutkimuksia tähystys-leikkaustekniikoistaOulun yliopiston tutkijakoulu; Oulun yliopisto, Lääketieteellinen tiedekunta; Medical ResearchCenter Oulu; Oulun yliopistollinen sairaalaActa Univ. Oul. D 1559, 2020Oulun yliopisto, PL 8000, 90014 Oulun yliopisto

Tiivistelmä

Arpityrä on yleinen leikkauskomplikaatio, ja sen korjaamista suositellaan kureutumisriskinvuoksi. Leikkaustekniikoita on useita. Suosittuun tähystysleikkaustekniikkaan tiedetään liitty-vän vakavan komplikaation, suolivaurion riski. Leikkausalueen nestekertymä on yleinen löydösleikkauksen jälkeen. Hybriditekniikassa kiinnikkeiden irrottelu tehdään pienen avauksen kauttaja tyräaukko suljetaan ennen verkon kiinnittämistä. Tutkimuksessa arvioimme tyräleikkaus-komplikaatioita keskittyen tähystysleikkaustekniikoihin. Selvitimme voiko hybriditekniikkaakäyttäen vähentää leikkauksen jälkeisen nestekertymän muodostumista ja tyrän uusiutumista.

Osatyö I kuvaili Potilasvakuutuskeskukseen vuosina 2003–2010 ilmoitettuja vatsan tyräleik-kauksiin liittyviä vahinkoja (n = 127). Osatyössä II analysoimme 818 tyränkorjausleikkauksentulokset keskittyen vakaviin komplikaatioihin. Osatyössä III verrattiin 38 tähystys- ja 24 hybri-dileikkauksien tuloksia tilanteissa, joissa todettiin hankalat kiinnikkeet. Prospektiivisessa moni-keskustutkimuksessa (osatyöt IV–V) 193 potilasta leikattiin satunnaistamisen mukaan tähystys-tai hybriditekniikkaa käyttäen.

Retrospektiivisissä osatöissä I–III totesimme, että tähystysleikkauksien vakavat komplikaati-ot liittyivät huomaamatta jääneisiin suolivaurioihin. Hankalilla kiinnikkeillä todettiin selkeäyhteys vakaviin komplikaatioihin, suolivaurioihin ja haavainfektioihin. Prospektiivisissa osatöis-sä IV–V kuvattiin viisi suolivauriota tähystysleikkauksien ja yksi hybridileikkauksien yhteydes-sä. Kiinnikkeiden irrottelu oli selvästi hankalampaa tähystysleikkauksissa. Tähystysleikkaustenjälkeen todettiin selvästi enemmän leikkausalueen nestekertymiä verrattuna hybridileikkauksiin.Vuoden kohdalla tyräuusiutumien määrässä ei ollut eroja ryhmien välillä; 11 (6,4 %) tyräuusiu-tumasta kuusi todettiin tähystys- ja viisi hybridiryhmässä.

Toteamme, että tähystysleikkauksiin liittyviä komplikaatiota on vähän, mutta suolivaurionriski on kohonnut leikkauksissa, joissa todetaan runsas kiinnikkeisyys. Hybriditekniikassa kiin-nikkeiden irrottelu käsin voi vähentää suolivaurion riskiä. Nestekertymän ilmaantuminen leik-kausalueelle on selvästi vähäisempää hybridileikkauksen jälkeen, mutta sen vaikutus tyränuusiutumisriskiin vaatii pidemmän seuranta-ajan. Potilaat ovat kivuttomia tyränkorjausleikkauk-sen jälkeen, mikä näkyy elämänlaadun kohenemisena.

Asiasanat: arpityrä, hybridi, suolivaurio, tyrän uusiutuminen, tähystysleikkaus

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To my Family

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Acknowledgements This project was carried out in the Department of Surgery at Oulu University Hospital from 2012–2020.

I am grateful to all my co-workers, colleagues, and friends for their support throughout the years on this project.

I wish to extend my deepest gratitude to my supervisor, Professor Jyrki Mäkelä, for your support and patient guidance during these years. Your vast experience in both clinical and scientific work is admirable. I am also indebted to my supervisor, Docent Tero Rautio, for your encouraging attitude, which has inspired me to go forward all these years. I respect your excellent clinical skills and passionate attitude towards scientific research. I was privileged to have such encouraging supervisors. You gave me the opportunity to step into the world of research and kindly guided me through this project. You were both also always there for me in times of struggle throughout this thesis.

I want to express my appreciation for my other supervisors, Professor Hannu Paajanen and Docent Jaana Vironen, for their guidance and support during the beginning of this thesis. I am also thankful for Jaana for all the advice and encouragement during these years as well as for Docent Jyrki Kössi for your expertise and valuable comments.

I express my warmest thanks to reviewers Docent Heikki Huhtinen and Docent Markku Luostarinen for helping me improve the quality of this thesis.

Additionally, I wish to extend my sincerest thanks to Docent Juha Saarnio, the Head of the Division of Gastrointestinal Surgery, for giving me the opportunity to do both clinical and scientific work and, especially, for his encouraging and positive attitude as my superior and a member of the follow-up group. To Professor Willy Serlo, I am deeply indebted to you for being such an efficient chairman of my follow-up group and also for the many delightful conversations about research, neighborhood, and kids. I also thank Docent Vesa Koivukangas for his practical advice and support as a member of the follow-up group.

I owe my deep gratitude to Pasi Ohtonen, M.Sc for the statistical assistance. You patiently helped me throughout these years and continued to explain statistical details to a point at which I at least thought I understood them. In those moments, occasionally, statistics almost felt fun.

I wish to thank all my co-authors and colleagues participating in to our multicentre study, with special thanks to Terhi Nevala, MD, PhD for the flexible

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co-work and expertise in radiology. I would also like to extend thanks to Teuvo Ryynänen, M.Sc. for his help editing this thesis to its final form.

Special thanks and gratitude go to my dear colleagues in the Division of Gastrointestinal Surgery, you gents and ladies! Your supportive and positive attitude has given me strength to carry on this study. I feel privileged to get to work surrounded by such great people and clinical experts. I am also deeply grateful for your participation in operating the patients and collecting the data as well as dealing with all the rap music in the OR.

My strength comes from my family and friends. I am thankful for such dear friends that life has brought to me. My heartfelt gratitude goes especially to my soul sister, Liliana, and Merja, Paula, Elina, and “Las Primaballerinas”, from Rovaniemi.

Above all, I owe my deepest thanks to my family. My parents, Anneli and Olavi, I truly thank you for the unconditional love and endless support, which has carried me through the challenges I have faced in life and along this project. No words can truly express my gratitude towards you. I am also grateful to my brother, Jani, for the support and always being a voice of reason for me. I express a special gratitude to my husband, Jari, for being there for me, helping me combine work as a surgeon and researcher and still have a family and two wonderful daughters. I also thank you for the technical help on uncountable occasions. My precious daughters, Liliana and Miralia, every day I am thankful for having you as my daughters. My heart is always with you.

This study was financially supported by the University of Oulu, Finnish Medical Foundation, The Finnish Cultural Foundation, Vatsatautien tutkimussäätiö, Mary and Georg C. Ehrnrooth Foundation, and Oulun Lääketieteen säätiö, which are all gratefully acknowledged.

Oulu, January 2020 Mirella Ahonen-Siirtola

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Abbreviations AD anno domini ASA-score American Association of Anesthesiologists physical score BMI body mass index CS component separation CT computed tomography EHS European Hernia Society eTEP enhanced-view total extraperitoneal EuraHS European Registry for Abdominal Wall Hernias ePTFE expanded polytetrafluoroethylene IEHS International Endohernia Society IH incisional hernia IPOM intraperitoneal onlay mesh IPOM plus intraperitoneal onlay mesh with defect closure by suture IVH incisional ventral hernia IVHR incisional ventral hernia repair LIVHR laparoscopic incisional ventral hernia repair MILOS mini- or less-open sublay MRI magnetic resonance imaging PPP preoperative progressive pneumoperitoneum QoL quality of life SF-36 short form 36 SSI surgical site infection TAPP transabdominal preperitoneal repair TAR transversus abdominis release TES total endoscopic sublay US ultrasound VAS visual analogue scale

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Original publications This thesis is based on the following publications:

I Ahonen-Siirtola, M., Vironen, J., Mäkelä, J., & Paajanen, H. (2014). Surgery-related complications of ventral hernia reported to the Finnish Patient Insurance Centre. Scandinavian Journal of Surgery, 104(2), 66–71. https://doi.org/10.1177/14574969 14534208

II Ahonen-Siirtola, M., Rautio, T., Ward, J., Kössi, J., Ohtonen, P., & Mäkelä, J. (2015). Complications in laparoscopic versus open incisional ventral hernia repair. A retrospective comparative study. World J Surg, 39(12), 2872–2877. https://doi.org/ 10.1007/s00268-015-3210-6

III Ahonen-Siirtola, M., Rautio, T., Biancari, F., Ohtonen, P., Mäkelä, J. (2017). Laparoscopic versus Hybrid Approach for Treatment of Incisional Ventral Hernia. Dig Surg, 34(6), 502–506. https://doi.org/10.1159/000458713

IV Ahonen-Siirtola, M., Nevala, T., Vironen, J., Kössi, J., Pinta, T., Niemeläinen, S., Keränen, U., Ward, J., Vento, P., Karvonen, J., Ohtonen, P., Mäkelä, J., Rautio, T. (2018). Laparoscopic versus hybrid approach for treatment of incisional ventral hernia: a prospective randomized multicenter study of 1-month follow-up results. Hernia, 22(6), 1015–1022. https://doi.org/10.1007/s10029-018-1784-2

V Ahonen-Siirtola, M., Nevala, T., Vironen, J., Kössi, J., Pinta, T., Niemeläinen, S., Keränen, U., Ward, J., Vento, P., Karvonen, J., Ohtonen, P., Mäkelä, J., Rautio, T. (2019). Laparoscopic versus hybrid approach for treatment of incisional ventral hernia: a prospective randomised multicentre study, 1-year results. Surg Endosc. 2019 Apr 2. https://doi.org/10.1007/s00464-019-06735-9 [Epub ahead of print]

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Contents Abstract Tiivistelmä Acknowledgements 9 Abbreviations 11 Original publications 13 Contents 15 1 Introduction 17 2 Review of the literature 19

2.1 History ..................................................................................................... 19 2.2 Timeline of hernia surgery ...................................................................... 19 2.3 Abdominal wall anatomy ........................................................................ 21 2.4 Hernia pathophysiology .......................................................................... 21 2.5 Incidence of incisional ventral hernias .................................................... 23 2.6 Classification for incisional ventral hernias ............................................ 24

2.6.1 European Hernia Society classification ........................................ 24 2.7 Diagnosis of incisional ventral hernias ................................................... 28

2.7.1 Symptoms and clinical diagnosis ................................................. 28 2.7.2 Radiological diagnosis.................................................................. 28

2.8 Treatment of incisional ventral hernias ................................................... 29 2.8.1 Conservative treatment ................................................................. 29 2.8.2 Operative treatment ...................................................................... 29 2.8.3 Hernia repair guidelines ............................................................... 35 2.8.4 Hernia repair materials ................................................................. 35 2.8.5 Preoperative preparation ............................................................... 37

2.9 Complications ......................................................................................... 38 2.9.1 Clavien-Dindo grading ................................................................. 38 2.9.2 Overall complication rate ............................................................. 41 2.9.3 Perioperative complications ......................................................... 41 2.9.4 Postoperative complications ......................................................... 41

2.10 Hernia prevention .................................................................................... 44 2.11 Quality of life .......................................................................................... 45 2.12 Patient Insurance Centre ......................................................................... 46

3 Aims of the study 47 4 Patients and Methods 49

4.1 Statistical analysis ................................................................................... 55

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5 Results 57 5.1 Study I ..................................................................................................... 57 5.2 Study II .................................................................................................... 58 5.3 Study III .................................................................................................. 60 5.4 Study IV–V ............................................................................................. 61

6 Discussion 71 6.1 Discussion of the main results ................................................................. 72

6.1.1 Comparison between the outcomes of operative techniques in Studies IV–V .......................................................... 72

6.1.2 Enterotomy ................................................................................... 72 6.1.3 Seroma formation ......................................................................... 73 6.1.4 Hernia recurrence ......................................................................... 73 6.1.5 Pain ............................................................................................... 74 6.1.6 QoL ............................................................................................... 75

6.2 Limitations of the thesis .......................................................................... 75 6.3 Clinical importance ................................................................................. 76 6.4 Future expectations ................................................................................. 76

7 Conclusions 79 References 81 Original publications 99

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1 Introduction An abdominal hernia is the protrusion of organs or tissue through a defect in the abdominal wall. Incisional ventral hernias (IVHs) develop at the site of a prior surgery via multifactorial pathogenesis and abnormal wound healing (Thankam, Palanikumar, Fitzgibbons, & Agrawal, 2019). Hernias can be asymptomatic but often they cause pain and discomfort, and can lead to serious complications, such as bowel incarceration. Therefore, IVHs are recommended to be repaired (Cassar & Munro, 2002). There are various operative techniques for hernia repair: Since the suturing technique, used in the early 1900s, resulted in a high hernia recurrence, the retromuscular prosthetic technique (Rives-Stoppa methods) using non-resorbable polypropylene or polyester mesh, became one of the most popular treatment for IVHs (Conze et al., 2005; Kingsnorth & LeBlanc, 2003). In 1993, LeBlanc and Booth published an article on the laparoscopic method for hernia repair (LeBlanc & Booth, 1993). Since then, laparoscopic hernioplasty has become widely used due to improved outcomes reported in several studies (Awaiz et al., 2015; Itani et al., 2010; Ramshaw et al., 1999; Rogmark et al., 2013; Zhang et al., 2014). The basic laparoscopic technique includes a reduction in the hernia material, exposing the hernia area, adhesiolysis, and then covering the defect with intraperitoneal onlay mesh (IPOM). The mesh is fixed to the abdominal wall with tackers and/or sutures (LeBlanc, 2005). Although laparoscopic treatment is widely used in IVH repair, the method is associated with a relatively rare but dangerous perioperative complication—enterotomy—especially in cases with complex adhesiolysis (Forbes, Eskicioglu, McLeod, & Okrainec, 2009; LeBlanc, Elieson, & Corder, 2007; ten Broek et al., 2012). Postoperative problems, such as bulging and seroma formation, are common findings following laparoscopic hernia repair (Bittner et al., 2014a; Sauerland, Walgenbach, Habermalz, Seiler, & Miserez, 2011). However, in this past decade, a technique called hybrid or IPOM plus has captured surgeons’ attention. Using this method, the fascial defect is closed either intracorporeally or through an incision before laparoscopic mesh augmentation (Chelala, Gaede, Douillez, Dessily, & Alle, 2003; Clapp, Hicks, Awad, & Liang, 2013; Franklin, Gonzalez, Glass, & Manjarrez, 2004; Palanivelu et al., 2007; Sharma et al., 2011) Hernia recurrence rates seem to be lower when combining defect closure and IPOM augmentation (Banerjee et al., 2012; Chelala et al., 2015), but no comparable studies have yet been published. For the purpose of improving hernia surgery in terms of safety and hernia recurrence, we conducted a study

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evaluating different operative methods and presented results from using this new hybrid technique.

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2 Review of the literature

2.1 History

Hernias as an abdominal surgical disease were first noted by Praxagoras of Kos in the early 16th century BC. There are also descriptions of abdominal wall closure by layers from the years 100–200 by Celsus and Galen (Faylona, 2017; Papavramidou & Christopoulou-Aletra, 2009). The first documented surgery for a ventral hernia was performed by Pierre Nicholas Gerdy, who inverted the hernia sac into the abdominal cavity and, after suturing the edges, injected ammonia into the sac to produce adhesions (Faylona, 2017). Simple suturing techniques became popular during the 19th century. In 1899, Mayo presented what is likely the most famous suturing method: using sutures in a figure eight and overlapping the aponeurotic layers transversely (Mayo, 1899). Silk, silver, fascial strips and later nylon were used in the darn method (Moloney, Gill, & Barclay, 1948). In 1910, Kirshner employed homologous, heterologous, and autologous grafts, with promising results from the autologous grafts (Faylona, 2017). In 1954, Natta and Ziegler introduced polypropylene mesh (Kapischke & Pries, 2014; Seymour et al., 1989), which became popular for hernia use in 1959 by Francis Usher (Read, 2009; Usher, Fries, Ochsner, & Tuttle, 1959). From the 60s to the 90s, there were various open methods for incisional ventral hernia repair (IVHR) until 1993 when LeBlanc and Booth introduced a laparoscopic technique for hernia repair (LeBlanc & Booth, 1993). The laparoscopic method has gained popularity since then, yet hernia surgery is a constantly evolving field of surgery. Overall, it remains to be seen whether new mini-invasive operative methods can offer more satisfying results for hernia repair than existing open and laparoscopic techniques.

2.2 Timeline of hernia surgery

The main events in the evolution of hernia surgery are presented in Figure 1.

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Fig.

1. T

imel

ine

of h

erni

a su

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y.

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2.3 Abdominal wall anatomy

The anterior abdominal wall consists of rectus muscles and the linea alba in the midline. The lateral boundary of the rectal sheath is called the linea semilunaris. Below the umbilicus is the linea arcuate, in which the posterior layer of rectal fascia changes into the peritoneum. Lateral to the rectus muscles are the external oblique, internal oblique, and transversus abdominis muscles (Pulikkottil et al., 2015). The anatomic structure of the abdominal wall can be seen in Figure2.

Fig. 2. Abdominal wall anatomy. Published with permission from Christy Krames, the American Academy of Family Physicians.

2.4 Hernia pathophysiology

The healing of wounds is a multifactorial process, and we currently lack knowledge of the basic biology behind the pathogenesis of incisional hernias. Some features, such as connective tissue and fibroblast quality, have been proposed to have an influence on the risk of hernia formation (Thankam et al., 2019). An inflammatory response following an incisional wound results in the initiation of the fibroproliferative phase. Researchers have also suggested that fibroblast proliferation is disturbed in the laparotomy wound matrix, resulting in an IVH

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(Xing, Culbertson, Wen, & Franz, 2013). Fascial ischemia is also presumed to be one crucial factor in the development of an IVH. The fascia is hypovascular, and a wound experiences hypoxic stress immediately after surgical incision, which has been considered a major risk factor of wound failure. Hypoxia interferes with angiogenesis and the healing process (Chang, Goodson, Gottrup, & Hunt, 1983). Moreover, revascularization at the wound site is critical to improve healing responses (Knighton, Silver, & Hunt, 1981). Good technical skills and maintaining sufficient perfusion in the wound area are important issues to be noted (Aicher et al., 2019). Along with matrisome alterations, patients’ comorbidities can predispose to developing a hernia, and it is known that connective tissue disorders with abnormal collagen production (Harrison, Sanniec, & Janis, 2016) increase the risk of herniation, among various other patient-related factors (Bosanquet et al., 2015) The continuous intra-abdominal pressure is 2–20 mmHg, but it can increase through coughing or vomiting up to 170 mmHg. When wound healing is in process, a simple increase in intra-abdominal pressure can cause the rupture of the wound (Klinge, Prescher, Klosterhalfen, & Schumpelick, 1997).

Fig. 3. Major contributing factors in progression of incisional hernia. ROS = reactive oxygen species (Thankam, Palanikumar, Fitzgibbons, & Agrawal, 2019, published with permission from Elsevier).

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2.5 Incidence of incisional ventral hernias

IVHs are a common complication of abdominal surgery, and their incidence varies greatly (2–30%) among studies (Hoer, Lawong, Klinge, & Schumpelick, 2002; Mudge & Hughes, 1985; Sajid, Bokhari, Mallick, Cheek, & Baig, 2009) and is influenced by several factors, such as surgical techniques (Harlaar et al., 2017; Patel, Paskar, Nelson, Vedula, & Steele, 2017, Koessler-Ebs et al., 2016), follow-up time (Fink et al., 2014) and the use of radiological investigations in combination with clinical examination for diagnosis (Bjork, Cengiz, Weisby, & Israelsson, 2015; Kroese, Sneiders, Kleinrensink, Muysoms, & Lange, 2018).

In terms of surgical techniques, it has been shown that the site of an incision has an influence on IVH rates. Non-midline incisions—both paramedian and transverse—carry a significantly reduced risk of IVHs compared to midline incisions (Bickenbach et al., 2013; Brown & Goodfellow, 2005). It has also been shown that closing techniques affect hernia rates. Using slowly-absorbable sutures (van 't Riet, Steyerberg, Nellensteyn, Bonjer, & Jeekel, 2002) and taking small bites of 5 mm with an intersuturing space of 5 mm results in a lower hernia incidence (Harlaar et al., 2017; Millbourn, Cengiz, & Israelsson, 2009; Patel, Paskar et al., 2017). Moreover, two recent studies showed that IVHs occur more frequently after open rather than laparoscopic approaches (Kossler-Ebs et al., 2016; Basta et al., 2019).

When evaluating IVH rates, the difference between physical examination and imaging techniques (ultrasound or computer tomography) is important in terms of accuracy (Aguirre, Casola, & Sirlin, 2004; Lassandro et al., 2011). A standardised examination and dynamic evaluation via an ultrasound of the abdominal wall is recommended in evaluating a possible hernia (Bittner et al., 2014a).

A significant factor in hernia diagnosis is the length of follow-up time. It has been reported that the incidence of IVHs increased during a follow-up. It is reported that the incidence of IVH increases during the follow-up time. Hoer et al. (2002) reported that 55% of IVHs develop after 12 months, 75% after two years and 89% after five years from surgery (Hoer et al., 2002). A similar finding was seen in another study by Fink et al. (2014); incidence of IVH was 12.6% at 12 months and 22.4% at 36 months (Fink et al., 2014).

According to another recent study, the most common patient-related factors for increasing the likelihood of developing an IVH are a history of previous abdominal surgeries, emergency surgery, or having several comorbidities (Basta et al., 2019). As a result of an analysis of 14 618 patients, Bosanquet et al. (2015) in their review

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and meta-regression determined the factors affecting midline IVH rates: diabetes mellitus, obesity, cachexia, increasing age, male sex, chronic obstructive pulmonary disease, a history of operation for an abdominal aortic aneurysm, anaemia, smoking, and corticosteroids and surgical site infection. Summarising the results of 56 publications, the prevalence of IVHs after midline laparotomy was 12.8% (range: 0 to 35.6%), with a mean follow-up time of 23.7 months (Bosanquet et al., 2015).

2.6 Classification for incisional ventral hernias

There is great diversity in abdominal wall hernias. Korenkow stated the following in 2000: “Incisional hernias are defined as abdominal wall gaps around postoperative scars, perceptible or palpable by clinical examination or imaging” (Korenkov et al., 2001). During the early 2000s, the first proposals for the classification of incisional ventral hernias were published. First, Schumpelick divided IVHs into five classes according to the defect size, localisation, number of previous repairs, and the clinical aspects of the hernia in both lying and standing positions (Muysoms et al., 2009). Throughout 2009, there were several proposals for classifying IVHs according to defect size, recurrence, and topography to some extent, but none of these achieved wide recognition or routine use (Chevrel & Rath, 2000; Dietz et al., 2007; Korenkov et al., 2001; Muysoms et al., 2009).

2.6.1 European Hernia Society classification

In 2009, the European Hernia Society (EHS) published a formula to classify primary and incisional abdominal wall hernias. The IVH was defined according to the proposition of Korenkov, and the new classification divided IVHs according to localization, taxonomy, and size (Muysoms et al., 2009).

The abdomen is divided into a midline zone and lateral zone. Bordering the midline area are, cranially, the xyphoid, caudally, the pubic bone, and, laterally, the lateral margin of the rectal sheath.

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Midline hernias are divided into the following subgroups M1–M5:

M1: subxiphoidal (from the xiphoid until 3 cm caudally), M2: epigastric (from 3 cm below the xiphoid until 3 cm above the umbilicus), M3: umbilical (from 3 cm above until 3 cm below the umbilicus), M4: infraumbilical (from 3 cm below the umbilicus until 3 cm above the

pubis) and M5: suprapubic (from the pubic bone until 3 cm cranially).

Lateral hernias are localised laterally to the rectal sheath: the cranial margin is the costal line, the caudal margin the inguinal region, and the lateral margin is the latero-dorsal of the anterior axillary line. The L zones can be defined as follows:

L1: subcostal (the costal margin: a horizontal line 3 cm above the umbilicus), L2: flank (lateral to the rectal sheath in the area 3 cm above and below the

umbilicus), L3: iliac (between a horizontal line 3 cm below the umbilicus and inguinal

region), L4: lumbar (latero-dorsal of the anterior axillary line)

The size of the hernia defect is classified by the width and marked as:

W1 < 4 cm W2 ≥ 4–10 cm W3 ≥ 10 cm (Muysoms et al., 2009)

The classification and zones of hernia sites are shown in Figures 4–6.

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Fig. 4. EHS classification for incisional abdominal wall hernias (Muysoms et al., 2009, published with permission from Springer Nature).

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Fig. 5. EHS classification: zones of midline hernias (Muysoms et al., 2009, published with permission from Springer Nature).

Fig. 6. EHS classification: zones of lateral hernias (Muysoms et al., 2009, published with permission from Springer Nature).

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2.7 Diagnosis of incisional ventral hernias

2.7.1 Symptoms and clinical diagnosis

Most commonly, an IVH is a bulge or gap in the area of a postoperative scar. It can be asymptomatic but is often associated with symptoms, such as pain, cosmetic discomfort, bowel obstruction, or even incarceration (Ah-Kee, Kallachil, & O'Dwyer, 2014; Cassar & Munro, 2002). Inspection and palpation are the main diagnostic methods for hernias. Valsalva’s manoeuvre was first described in 1704 by Antonio Maria Valsalva and is used to make a hernia more clinically apparent: an increase in intraabdominal pressure causes the hernia sac to enlarge and protrude through the anatomic defect. This examination can be performed in both standing and supine positions (Light & Routledge, 1965).

2.7.2 Radiological diagnosis

Physical examination can be difficult in obese patients or in postoperative situations in which it is difficult to distinguish a hernia from a postoperative complication, such as a hematoma, abscess, or seroma (Jaffe, O'Connell, Harris, Paulson, & Delong, 2005). In some cases, to recognize a possible hernia or support clinical findings, radiological imaging (ultrasound (US), computed tomography (CT), or magnetic resonance (MRI)) can be useful in specifying a diagnosis (Bjork et al., 2015; Bloemen, van Dooren, Huizinga, & Hoofwijk, 2012; Emby & Aoun, 2003; Hojer, Rygaard, & Jess, 1997). A standardised dynamic abdominal sonography for hernias offers a safe and low-cost diagnostic tool with great specificity and positive predictive value (den Hartog, Dur, Kamphuis, Tuinebreijer, & Kreis, 2009). A CT can also be an option in some cases, although it induces radiation load for patients. Thus, accurate physical exams and clinical information is highly important, as it can affect the radiologist’s reading of CT scans (Cherla et al., 2018; Holihan, Karanjawala et al., 2016).

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2.8 Treatment of incisional ventral hernias

2.8.1 Conservative treatment

The conservative management, a watchful waiting strategy, of IVHs is used in selective cases of elderly patients and patients with severe co-morbidities (Kokotovic, Sjølander, Gögenur, & Helgstrand, 2016). While there is no exact description for the natural course of an IVH and the risk of incarceration (Lauscher et al., 2012), it is still known that a significant proportion of hernias require emergency surgery, which is associated with higher postoperative complication rates than elective surgery (Alvarez Perez et al., 2003; Davies, Davies, Morris-Stiff, & Shute, 2007). Along with the risk of incarceration, pain and limitations to daily activities are considered the most major indications of hernia repair (Nieuwenhuizen, Kleinrensink, Hop, Jeekel, & Lange, 2008).

2.8.2 Operative treatment

There are various operative techniques for IVHR. Patient-related factors (e.g. comorbidities, age, BMI, previous operations), surgeons’ experience, and evaluation of operative risks should be considered when choosing a suitable method for each patient.

Suturing methods

Suturing of the abdominal wall layers was first published by Celsus in 100 AD (Papavramidou & Christopoulou-Aletra, 2009). Many types of suturing techniques and materials were introduced throughout the 19th century, the most popular of which was using sutures in a figure eight and overlapping the aponeurotic layers transversely, as Mayo described in 1899 (Mayo, 1899); however, the results of these methods were disappointing in terms of hernia recurrence (den Hartog, Dur, Tuinebreijer, & Kreis, 2008; Paul et al., 1998). According to the publications, hernia recurrence rates for suturing method have ranged from 34% (Manninen, Lavonius, & Perhoniemi, 1991) to 84% (Mittermair, Klingler, Wykypiel, & Gadenstatter, 2002). Currently, the suturing technique is rarely used and not recommended even for small (< 2 cm) hernias (Bittner et al., 2019a; Shrestha, Shrestha, & Shrestha, 2019).

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Open mesh repair

Francis Usher (1959) made polypropylene mesh repair popular in 1959 using Marlex mesh (Usher et al., 1959). For the next decades, open mesh repair was a frequently used method in hernia repair. The main positions in which to place this mesh are as follows: In the “onlay” method by Chevrel, the mesh is fixed on the anterior fascia (Haskins et al., 2017). “Inlay” is also known as a bridging technique, in which the mesh is sutured into the medial edges of the gap (Holihan, Nguyen et al., 2016). “Sublay” means placing the mesh into a retromuscular space or preperitoneally, known as the Rives-Stoppa method. In the sublay technique, the hernia sac is dissected from the surrounding fascia, and a space in the retromuscular or preperitoneal plane is developed to facilitate appropriate mesh overlap (Bauer, Harris, Gorfine, & Kreel, 2002; Rives, Pire, Flament, & Convers, 1977; Stoppa, Louis, Verhaeghe, Henry, & Plachot, 1987). Figure 7 shows the mesh positions.

Fig. 7. Mesh positions. A = onlay, B = inlay, C = sublay, D = intraperitoneal onlay (Holihan et al., 2016, published with permission from Springer Nature).

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In open hernioplasties, wide tissue dissection increases the risk of surgical site infection, which is a known complication associated with open mesh repair (Holihan, Bondre et al., 2016). According to the recent meta-analysis, the sublay position exhibits the lowest recurrence and surgical site infection rates when compared to other open mesh repair techniques (Holihan et al., 2016).

Hernia recurrence has been shown to decrease when using prosthetic meshes. The results of two randomised studies comparing the suture and mesh repair of IVHs showed significantly superior results than prosthetics repair: the rates of hernia recurrences were 43–63% for suture repair and 24–32% for mesh repair (Burger et al., 2004; Luijendijk et al., 2000). Recent results for open mesh repair have shown even lower recurrence rates of 8–16.9% (Cobb et al., 2015; Rogmark, Smedberg, & Montgomery, 2018).

Component separation techniques

For complex, large IVHs, one can use three component separation (CS) methods in which the fascia at the linea semilunaris site is incised to deliberate the muscular layers and allow for midline closure.

Ramirez, Ruasm and Dellon (1990) developed an anterior CS technique in 1990: The subcutaneous space is widely dissected, the external oblique muscle is incised laterally from the linea semilunaris, and the space under the external oblique muscle is dissected. Using this method, up to 10 cm can be gained to release and suture the rectus muscle back to the midline (Ramirez et al., 1990). This technique has been associated with a recurrence rate of 4–14.9% (Hodgkinson et al., 2018).

Posterior CS was developed by Carbonell, Cobb, and Chen (2008). In this technique, from a midline incision, the posterior rectus sheath is incised medial to the linea semilunaris, and a space between the internal oblique muscle and transversal muscle is created. The neurovascular bundles are preserved. The posterior rectus sheath is sutured, and a large mesh is placed into the created space and covered with the anterior rectus sheath. This is a feasible method for the repair of large fascial defects with an adequate overlap of mesh, exhibiting a recurrence rate of 3.1–5% (Carbonell et al., 2008; Hodgkinson et al., 2018).

Posterior CS can also be combined with transversus abdominis release (TAR), as reported by Pauli et al. in 2015. With TAR, a wider space can be gained compared to basic posterior CS. In this technique, instead of dissecting the plane between the internal oblique and transversal muscle, the transversal muscle is cut, and space is created underneath (Pauli et al., 2015). TAR’s recurrence rate is as low as 3–8.5%

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(Hodgkinson et al., 2018; Novitsky, Elliott, Orenstein, & Rosen, 2012; Pauli et al., 2015).

Laparoscopic technique

Laparoscopic incisional ventral hernia repair (LIVHR) was introduced as a minimally invasive method in 1993 by LeBlanc, who used intraperitoneally placed expanded polytetrafluoroethylene (EPTFE) mesh (LeBlanc & Booth, 1993). In this laparoscopic IPOM technique, trocars are placed on the lateral side of the abdomen as far from the hernia defect as possible. All adhesions are lysed, and fascial defects are exposed along with the surrounding area, to which the mesh is attached. An appropriate-sized mesh covers the entire scar. The overlap of the mesh should be considered according to the defect size; at least 3–5 cm, or for larger defects the mesh area-to-defect-area ratio should be 16:1. The mesh is centred on the defect and attached to the abdominal wall with sutures and/or absorbable or permanent tackers using the double crown technique. Anchoring transfascial sutures can also be used (Birch, 2007; LeBlanc, 2016; LeBlanc & Booth, 1993, Bittner et al., 2014a, Bittner et.al., 2019a). Since the 1990s, laparoscopic incisional ventral hernia repair has gained popularity due to its positive postoperative outcomes. In several meta-analyses of randomized controlled trials comparing laparoscopic to open abdominal incisional hernia repair techniques, the laparoscopic technique has been proven to be as effective and safe as open repair while also appearing to have a significantly reduced rate of SSIs (Sauerland et al., 2011, Al Chalabi, Larkin, Mehigan, & McCormick, 2015; Dietz, Menzel, Lock, & Wiegering, 2018; Forbes et al., 2009; Heniford, Park, Ramshaw, & Voeller, 2003; Misra, Bansal, Kulkarni, & Pawar, 2006); Sajid et al., 2009; Sauerland et al., 2011; Turner & Park, 2008; Zhang et al., 2014). However, there are still problems associated with this technique. Perioperatively, there is a known risk of enterotomy, which is especially related to adhesiolysis (LeBlanc et al., 2007; ten Broek et al., 2012). The failure to restore the abdominal wall structure usually leads to dysfunction and bulging, which, aside from the cosmetic problem, can cause discomfort and dissatisfaction (Kurmann, Visth, Candinas, & Beldi, 2011; Schoenmaeckers, Wassenaar, Raymakers, & Rakic, 2010; Tse, Stutchfield, Duckworth, de Beaux, & Tulloh, 2010). Another typical postoperative finding is seroma formation, which can be painful and lead to seroma infection and later to mesh-related problems, such as infection (Edwards, Angstadt, Whipple, & Grau, 2005) and hernia recurrence (Banerjee et al., 2012; Mercoli et al., 2017; Sodergren & Swift, 2010). Recently, it

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has been shown that intraperitoneal mesh placement is associated with adhesion formation that may increase the risk for enterotomy during subsequent laparoscopic surgery. Especially in operations for bowel obstructions, the risk of enterotomy is increased as a direct result of mesh-bowel adhesions (Patel, Love et al., 2017, Sharma et al., 2013).

Hybrid

To avoid the common problems associated with basic laparoscopic hernia repair, a hybrid technique, or “IPOM plus”, has been recently established. In this method, the hernia defect is closed either intracorporeally (Chelala et al., 2003; Martin-Del-Campo, Miller, Elliott, & Novitsky, 2018) or through a mini-incision by suturing the fascial edges using slowly absorbable sutures prior to mesh augmentation (Stoikes, Quasebarth, & Brunt, 2013). When using the mini-incision route, adhesions can be lysed hand-assisted (Griniatsos, Yiannakopoulou, Tsechpenakis, Tsigris, & Diamantis, 2009). In the hybrid technique, the physiologic restoration of the abdominal wall anatomy and function can be achieved, resulting in a better cosmetic outcome. By closing the gap and reducing the death space left from the hernia sack, the formation of seroma can be diminished (Agarwal, Agarwal, & Mahajan, 2009; Martin-Del-Campo et al., 2018; Palanivelu et al., 2007 Sadava, Pena, & Schlottmann, 2019). Also, due to this greater mesh overlap, it has been suggested that hernia recurrence rates can be as low as 0–2.9% (Booth et al., 2013; Light & Bawa, 2016; Nguyen, Nguyen, Askenasy, Kao, & Liang, 2014).

In 2014, the International Endohernia Society (IEHS) published guidelines for the laparoscopic treatment of ventral and incisional abdominal wall hernias and introduced a recommendation for tension-free fascial closure to be combined with standard laparoscopic hernia repair (augmentation repair) (Bittner et al., 2014a). Figure 8 demonstrates the IPOM technique with and without the defect closure (Muysoms et al., 2013).

Robotic hernia repair

One of the latest advances in minimally invasive hernia repair is the robotic technique. It combines the advantages of open surgery with complete abdominal wall reconstruction and the restoration of functional anatomy with a decreased wound infection rate and recovery time following laparoscopy (Warren, Cobb, Ewing, & Carbonell, 2017). The main reason for introducing robotic assistance to

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hernia repair was to ease the closure of the fascial defect (Gonzalez et al., 2015). Another benefit seems to be the possibility of the intracorporeal augmentation of a large mesh into the abdominal wall (Kirkpatrick, Zimmerman, & LeBlanc, 2018). However, robotic surgery is associated with higher costs compared to other hernia operations, with no evidence of long-term results and thus should be considered carefully when choosing it as an operative method (Bittner, 2019b).

Fig. 8. Laparoscopic fixation of the mesh with and without defect closure (Muysoms et al., 2013, published with permission from Springer Nature).

New techniques

During the last few years, several new techniques for IVH repair have been introduced. These methods aim to restore the anatomy of the abdominal wall, extraperitoneal mesh augmentation, abandonment of penetrating fixation elements, minimal surgical access trauma of the abdominal wall, and minimized intraperitoneal dissection. The mesh position varies from preperitoneal to retromuscular, rectorectal and onlay. These different approaches can be carried out transhernially or at a distance from the abdominal wall defect via laparoscopic transperitoneal, endoscopic subcutaneous, or endoscopic retromuscular/ preperitoneal approaches (Bittner et al., 2019b). These new methods include the following techniques: endoscopic-accessed hernioplasties, such as mini- or less-open sublay (E-MILOS and MILOS) (Reinpold et al., 2019), enhanced-view totally

Legends

skin

abdominal wall

intraperitoneal mesh

tackers

suture

§

§

Double crown fixation

Double crown fixationwith defect closure

§ § §

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extraperitoneal (eTEP-access) ventral hernia repair (Belyansky et al., 2018) and totally endoscopic sublay (TES) (Li, Qin, & Bittner, 2018), laparoscopic transabdominal preperitoneal mesh repair (Zheng, Zhu, Zhang, & Zhang, 2019), laparoscopic Rives-Stoppa sublay repair (Schroeder, Debus, Schroeder, & Reinpold, 2013), and posterior CS combined with transversus abdominis muscle release (TAR) (Strey, 2014) in addition to various robotic-assisted hernia repair techniques, IPOM, TAPP, eTEP Rives-Stoppa, and eTEP-TAR (Belyansky et al., 2018; Gokcal, Morrison, & Kudsi, 2019; Orthopoulos & Kudsi, 2018).

2.8.3 Hernia repair guidelines

During the last decade, there have been two guidelines published on laparoscopic ventral hernia repair. These guidelines include recommendations to help surgeons standardise their techniques and improve their treatment of patients. The first Italian Consensus Conference was held in 2010 to establish a common approach on laparoscopic ventral hernia repair (Cuccurullo et al., 2013). 11 statements, including the indications, technical details, and management of complications, were drafted based on the literature and experts’ comments. The conclusion was that the laparoscopic approach is safe and effective for defects larger than 3 cm. Careful adhesiolysis, mesh overlapping of least 3 cm, and the appropriate fixation of the graft, among other the technical issues, were recommended. In 2014, the IEHS published guidelines for the laparoscopic treatment of ventral and incisional abdominal wall hernias Parts 1–3 (Bittner et al., 2014a, 2014b, 2014c). It was a wide, thorough, evidence-based entity, including sections on technical issues, peri- and postoperative management, and new technology developments. These guidelines were recently updated in 2019 (Bittner et al., 2019a, 2019b).

2.8.4 Hernia repair materials

There is a significant variety of meshes, sutures, and tackers used in hernia repair, yet there is no clear consensus on the usage of a particular type of mesh or fixation material.

Mesh

In incisional ventral hernia repair, the mesh is most often placed either laparoscopically into the peritoneal surface of the abdomen as intraperitoneal onlay

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mesh (IPOM) or via an open method into the retrorectal space (sublay). Meshes used in these operations differ in material and structural conformation, including fibre, textile pattern, and pore size. These factors influence interactions with the tissue and the mechanical properties of the mesh. (Todros, Pavan, & Natali, 2017; Todros, Pavan, Pachera et al., 2017) To clarify prosthesis in use, a recent study categorised meshes based on biomaterial composition as simple (prosthetics made of one pure biomaterial), composite (prosthetics made of two or more different layers), combined (prosthetics made of two materials knitted or woven together), and biologic. Classification is based on weight:

Ultra-light < 35 g/m2, 35 ≤ Light < 70 g/m2, 70 ≤ Standard < 140 g/m2 and Heavy ≥ 140 g/m2.

Permanent synthetic meshes (polypropylene, polyester, and polytetrafluoroethylene) are attached between the abdominal wall layers, and multilayered and meshes with coated barriers (collagen, glycerol, sodium hyaluranate, carboxy methylcellulose, and polyethylene glycol) can be used intra- abdominally (Coda, Lamberti, & Martorana, 2012). The fibres of the mesh can be either mono-or multifilaments and woven or knitted (Todros, Pavan, & Natali, 2017). Mesh porosity should be over 1 millimetre to allow for tissue ingrowth and reduce the risk of infection (Muhl, Binnebosel, Klinge, & Goedderz, 2008). Light-weight meshes are associated with less shrinkage compared to heavy-weight meshes due to their greater porosity (Brown & Finch, 2010). The tensile strength of the mesh depends on the weight of its polymer and pore size, and it is known that coughing can raise the intra-abdominal pressure up to 170 mmHg. Meshes are known to bear twice this pressure without bursting; however, mesh ruptures can still occur (Cobb et al., 2005).

Among the synthetic meshes, biological meshes are often used as well. These grafts consist of an extracellular matrix-derived collagen tissue of dermis, pericardium, or small intestinal submucosa from human or animal origins (Deeken et al., 2012). Biological meshes are absorbable and more infection-resistant than synthetic materials; however, these grafts have been observed to lose tensity and durability in the long-term (Kockerling et al., 2018). It has also been stated that biological meshes can be considered in contaminated circumstances (Bittner et al., 2014b). Rosen, in his COBRA study, showed that biosynthetic mesh has a superior

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outcome in hernia recurrence compared to biological mesh in cases with complex situations (Rosen et al., 2017). A new approach that has been introduced is the use of a slowly absorbable biosynthetic mesh designed to combine the advantages of both synthetic and biological meshes and allowing for neovascularisation and tissue ingrowth (Miserez et al., 2019).

Fixation

There are several kinds of fixation materials used to attach mesh into the abdominal wall, and the most commonly used techniques are suturing and/or tacking. There are several permanent and absorbable tackers and sutures currently in use. According to the statements from the IEHS guidelines, the fixation technique does not influence postoperative pain or hernia recurrence (Bittner et al., 2014c). Moreover, additional glue fixation should be used in the costal margin and xiphoid area. The placement of the fixation is one of the key factors in preventing perioperative complications, such as hematoma and nerve injuries, and avoiding postoperative loose tacks and mesh migration. The recently updated IEHS guidelines stated that, to minimize the risk of hernia recurrence, suture fixation alone or with tacks or the double crown technique are recommended (Bittner et al., 2019a).

2.8.5 Preoperative preparation

Botulinum toxin injections

The primary closure of large hernias with the lateral retraction of the abdominal muscles can be complicated to achieve. Recently, botulinum toxin injection treatment has been observed as a potential way in which to achieve abdominal wall relaxation, thus enabling tension-free fascial defect closure when repairing giant hernias. A recent meta-analysis showed that significant hernia width reduction (mean 5.9 cm) and lateral muscular lengthening can be gained following botulinum injections (Weissler et al., 2017).

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Preoperative progressive pneumoperitoneum

In large ventral hernias, and with a great loss of domain, replacing hernia content into the peritoneal cavity can be challenging. In these situations, following hernia repair, intra-abdominal pressure can rise postoperatively, leading to a risk of abdominal compartment syndrome (Renard et al., 2016). To prevent these complications, Moreno (1947) presented a preoperative progressive pneumoperitoneum (PPP) (Moreno, 1947). Indications of PPP are mostly midline and lateral IVHs with a loss of domain and a transverse diameter greater than 10 cm and/or a hernia sac volume 15–20% compared to the abdominal cavity. This procedure is usually combined with botuline toxin injections (Cuminal et al., 2017, Bueno-Lledo, Torregrosa, Jimenez, & Pastor, 2018). Preoperatively, a CT scan is performed to evaluate the volume of the hernia sac and abdominal wall structures. Using ultrasound guidance and local anaesthesia, an intraperitoneal catheter is then placed and air is brought into the intra-peritoneal space to increase the volume of the abdominal cavity (Cuminal et al., 2017).

2.9 Complications

2.9.1 Clavien-Dindo grading

The Clavien classification was presented to classify and grade surgery-related complications and was revised and validated in 2004 (Dindo, Demartines, & Clavien, 2004). It ranges from Class I, denoting a minimal deviation from the normal postoperative course without the need for pharmacological treatment or surgical, endoscopic, or radiological intervention, to Class V, indicating postoperative death. Modifying the Clavien-Dindo grading, Kaafarani, Hur, Campasano, Reda, and Itani (2010) presented a methodology for the valuation of complications of IVH repair, as shown in Table 1 (Kaafarani et al., 2010).

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Tabl

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terv

entio

n N

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unde

r gen

eral

ane

sthe

sia

1) S

erom

a re

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ng p

ercu

tane

ous

aspi

ratio

n

2) In

tra-a

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cess

requ

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per

cuta

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s dr

aina

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3) S

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ite in

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ion

requ

iring

inci

sion

and

dra

inag

e

4) S

kin

necr

osis

requ

iring

bed

side

deb

ridem

ent

IIIB

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terv

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n un

der g

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al a

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a 1)

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el in

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tra-a

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rativ

e dr

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ge

3) P

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pera

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el o

bstru

ctio

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tive

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rven

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kin

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requ

iring

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rativ

e in

terv

entio

n

5) T

roca

r site

her

niat

ion

requ

iring

OR

repa

ir

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40

Cla

ss

Def

initi

on

Exa

mpl

es in

VIH

2

IV

Life

-thre

atin

g co

mpl

icat

ion

(incl

udin

g C

NS

1 com

plic

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ns5 )

requ

iring

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ent

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ingl

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ion

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sis

IVB

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ulti-

orga

n dy

sfun

ctio

n S

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s w

ith m

ulti-

orga

n fa

ilure

V

Dea

th o

f a p

atie

nt

Pos

tope

rativ

e de

ath

Suf

fix ‘d

’: If

the

patie

nt s

uffe

rs fr

om a

com

plic

atio

n at

the

time

of d

isch

arge

, the

suf

fix ‘d

’ (fo

r ‘di

sabi

lity’

) is

adde

d to

the

resp

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ass

of c

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s

labe

l ind

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es th

e ne

ed fo

r a fo

llow

-up

to fu

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ate

the

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1 ce

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ntra

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term

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tens

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t, 5 B

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age,

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ke, s

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2.9.2 Overall complication rate

Hernioplasties exhibit a morbidity of 15–20% (Espinosa-de-Los-Monteros et al., 2006; Kroese et al., 2018; Sanchez et al., 2018) and mortality of 0.05% (LeBlanc et al., 2007). Their overall complication rate includes both surgical and non-surgical complications and varies markedly among studies, which indicate it is lower in laparoscopic procedures compared to open (3.9–32% vs. 13.4–48%) (Itani et al., 2010; Kaafarani et al., 2010; Olmi, Scaini, Cesana, Erba, & Croce, 2007; Stipa et al., 2013).

2.9.3 Perioperative complications

Perioperative complications are rare in hernia operations, with an incidence of 2.5%. The most recognized intraoperative complications are bleeding, bowel perforation, and bladder injury (Sanchez et al., 2018). Bleeding is shown to be more common in open operations (Eker et al., 2013; Kurmann et al., 2011). A possibly dangerous complication, enterotomy, is more frequent in laparoscopic than open operations (Zhang et al., 2014). Iatrogenic injury can occur when entering the abdomen, during adhesiolysis, and using electrocautery. Moreover, bowel injury can remain undetected, especially in laparoscopic operations. This can lead to severe adverse events, such as life-threatening postoperative complications, increasing morbidity and mortality rates (LeBlanc et al., 2007; Sharma et al., 2013; van Goor 2007). Complex adhesiolysis is related to the increased risk of enterotomy and postoperative complications (Bensley et al., 2013; Gray et al., 2008; ten Broek et al., 2012; Van Der Krabben et al., 2000).

2.9.4 Postoperative complications

The postoperative complication rate varies greatly between studies comparing open and laparoscopic operations (10.5–47.9% vs. 3.4–31.5%). According to several studies, open hernioplasties are more often associated with postoperative complications than laparoscopic operations (Kockerling et al., 2019; Mason, Moazzez, Sohn, Berne, & Katkhouda, 2011; McGreevy et al., 2003; Stipa et al., 2013). The most common complications noted are pain, wound infections, and seromas, followed by hematomas, ileus, pneumonia, and urinary tract infections, which are known but relatively rare postoperative complications (Eker et al., 2013; Kockerling et al., 2019). It seems that closing the defect in laparoscopic

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hernioplasty can affect the incidence of surgical site events, seroma formation, and hernia recurrence (Martin-Del-Campo et al., 2018; Tandon et al., 2016).

Seroma

Seroma formation is a common finding following hernia repair, with its incidence varying from 0.5% to 78% according to the literature (Morales-Conde, 2012; Sauerland et al., 2011). The real importance of seroma formation is unclear, as it is mostly an asymptomatic clinical or radiological finding. According to the seroma definition published by Morales-Conde in 2012 (Table 2), seromas lasting more than six months or causing pain, discomfort, cellulitis, or infection are considered postoperative complications (Morales-Conde, 2012). The infection of the seroma is considered one of the most unfortunate complications, since it might lead to mesh removal (Edwards et al., 2005) and hernia recurrence (Banerjee et al., 2012; Sodergren & Swift, 2010). Seroma formation seems to be highly common following laparoscopic hernia repair, in which the fascial defect is left open (Morales-Conde, 2012). Recent results have indicated that closing the defect can lead to a lower seroma incidence (Tandon et al., 2016; ten Broek et al., 2012; Zeichen et al., 2013).

Infection

Surgical site infection (SSI) or wound infection is a common complication following an open hernioplasty. A wide soft tissue dissection can predispose patients to wound infection (Al Chalabi et al., 2015). Most infections can be treated conservatively with antibiotics, but they can also demand radiological drainage or surgical intervention. In the worst cases, an SSI can lead to sepsis and an infection of the mesh and, subsequently, to mesh removal (Plymale et al., 2019). Using mini-invasive techniques, the rate of surgical site infection has been observed to be lower compared to open hernia repair techniques (3.8–5.8% vs. 16.8–26.8%) (Arita et al., 2014; Kurmann et al., 2011; Pierce, Spitler, Frisella, Matthews, & Brunt, 2007).

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Table 2. A new seroma classification following laparoscopic ventral hernia repair (Morales-Conde, 2012, published with permission from Springer Nature).

Type Definition Grade

Type 0 No clinical seroma No clinical seroma

0a neither clinical nor radiological seroma

0b no clinical seroma, but it can be detected by radiological exams Type I Clinical seroma lasting less than 1 month Incident Type II Clinical seroma lasting more than 1 month: seromas with excessive

duration

IIa between 1 and 3 months

IIb between 3 and 6 months Type III Minor seroma related-complications: symptomatic seromas that may

need medical treatment

Complication

IIIa Clinical seroma lasting more than 6 months

IIIb Esthetic patient complaints due to seroma

IIIc Important discomfort that does not allow for normal activity

IIId Pain

IIIe Superficial infection with cellulitis Type IV Major seroma related-complication: seromas that need to be treated

IVa Need to puncture the seroma to decrease symptoms

IVb Seroma drained spontaneously (applicable to open approach)

IVc Deep infection

IVd Recurrence related to seroma

IVe Mesh rejection related to seroma

Pain

Pain is a common issue experienced in the early postoperative days, and it can lead to a significant concern related to the restriction of daily activities. Adequate medication administered postoperatively can prevent the development of chronic pain (Nguyen et al., 2008). Chronic pain is defined as lasting at least three months postoperatively (Bittner et al., 2014c). Operative techniques can influence the intensity and duration of postoperative pain. Still, according to two meta-analyses, no differences between pain scores after open and laparoscopic operations were shown (Al Chalabi et al., 2015; Zhang et al., 2014). The incidence of chronic pain after laparoscopic hernia repair ranges between 1.3–14.7% (Cocozza et al., 2014; Heniford et al., 2003; Sharma et al., 2011). It seems that with the tension-free

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closure of the defect before laparoscopic mesh attachment, even lower pain incidence can be achieved (2.6%) (Chelala et al., 2015).

Recurrence

Diminishing the recurrence rate is one of the main goals in improving hernia surgery, with several factors influencing reported hernia recurrence.

The IEHS stated in 2014 that a large hernia size (> 10 cm), body mass index (BMI) > 30 kg/m2, history of previous hernioplasty, chronic obstructive pulmonary disease or cough, diabetes, smoking, and SSI have been identified as patient-related risk factors for hernia recurrence (Bittner et al., 2014a).

The evaluation methods used can affect the detection of a recurrent hernia. A recurrent hernia is typically detected upon clinical examination, while in some cases, especially with obese patients, a radiological confirmation is needed (Bjork et al., 2015). A precise definition of a recurrent hernia is crucial since high variability has been noted in hernia recurrence among radiologists (Holihan, Karanjawala et al., 2016).

The length of the follow-up period is of great importance when evaluating hernia recurrence, since the recurrence rates are shown to progressively increase during the follow-up period. A long-term follow up can be considered as at least a three-year period (Kokotovic, Bisgaard, & Helgstrand, 2016; Yoo, Corso, Chung, Sheng, & Schmitz, 2018).

The operative method can influence the recurrence rate. According to recent meta-analyses, no clear differences between open and laparoscopic methods have been shown (Al Chalabi et al., 2015; Awaiz et al., 2015). On the other hand, there are comparative publications indicating that the laparoscopic method is associated with a lower risk of hernia recurrence (4.3% vs. 12.1%) (Pierce et al., 2007; Salvilla, Thusu, & Panesar, 2012; Yoo et al., 2018). In recent studies, LIVHR combined with defect closure (hybrid or IPOM plus) has been introduced as having even more promising recurrence outcomes of 0–4.7% (Baker, Oberg, Andresen, & Rosenberg, 2018; Banerjee et al., 2012; Chelala et al., 2015; Orenstein, Dumeer, Monteagudo, Poi, & Novitsky, 2011).

2.10 Hernia prevention

As one of the major issues in the field of abdominal surgery, IVH carries an economic burden, causing postoperative disabilities and reinterventions (Gillion,

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Sanders, Miserez, & Muysoms, 2016). Thus, hernia prevention offers considerable opportunities to impact postoperative morbidity and costs (Timmermans et al., 2013).

In 2014, the European Hernia Society (EHS) published guidelines on the closure of abdominal wall incisions (Muysoms et al., 2015), highlighting a few technical issues that are presumed to influence hernia formation. To decrease the incidence of IVH, it is recommended to utilise a non-midline approach for a laparotomy whenever possible. For elective midline incisions, using a continuous single-layer aponeurotic closure technique with slowly absorbable monofilament sutures is strongly suggested (Bittner et al., 2014a, Muysoms et al., 2015). Closing the fascia with “the small bites technique” (taking bites of fascia of 5–8 mm and placing stitches every 5 mm with a suture length /wound length ratio of at least 4:1) is recommended (Israelsson & Millbourn, 2013; Muysoms et al., 2015). A prophylactic mesh augmentation is shown to be an effective and safe technique in hernia prevention and therefore can be suggested for high-risk patients (e.g., after aortic aneurysm surgery and in obese patients) (Jairam et al., 2017).

2.11 Quality of life

There are several generic quality of life (QoL) scores used to evaluate treatment findings, and one of the most common scaling systems is the generic short-form (SF-36) questionnaire (Ware & Sherbourne, 1992). The SF-36 measures eight scale scores: physical functioning, role functioning (physical), role functioning (emotional), bodily pain, general health, vitality, social functioning, emotional wellbeing, and changes in health. It has also been shown that patients with an IVH report lower mean scores for the physical components of health-related QoL and body image (van Ramshorst, Eker, Hop, Jeekel, & Lange, 2012). According to studies measuring the influence of LIVHR on QoL, LIVHR appears to reduce chronic pain and physical impairment and improve long-term QoL (Eriksen et al., 2009; Langbach, Bukholm, Benth, & Rokke, 2016; Rogmark et al., 2016). When evaluating postoperative outcomes, patients have reported significantly greater event-free recovery following laparoscopic rather than open hernioplasty (85% vs. 65%). Overall, 92% of patients are satisfied with their results after one year (Rogmark et al., 2016). Due to increasing interest in patient-reported outcome measurements to evaluate hernia operations, two hernia-spesific QoL scaling systems have been published in the last decade. Krpata et al. (2012) introduced a 12-question survey called HerQLes for assessing patient-centered abdominal wall

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functional improvements after VHR (Krpata et al., 2012). Additionally, the European Registry for Abdominal Wall Hernias (EuraHS) published a QoL scaling system targeting patients with abdominal wall hernia repair. The EuraHS-QoL score is a short, nine-question form for the assessment of pre- and postoperative data based on a numerical rating scale of three dimensions: pain at the site of the hernia or hernia repair, restriction of activities, and cosmetic discomfort (Muysoms et al., 2012).

2.12 Patient Insurance Centre

The Finnish Patient Insurance Centre covers every patient and ensures compensation for injuries connected to patients’ medical or surgical treatment. No proof of malpractice is required. Patients who believe they have been exposed to an avoidable injury or malpractice in healthcare can present a claim for compensation from the centre. Patient insurance compensates costs such as medical treatment expenses, loss of income, pain and suffering, permanent functional defect, or permanent cosmetic injuries following surgery. Minor complications considered tolerable (e.g. superficial wound infections) or consequences considered unavoidable are not compensated (https://www.pvk.fi).

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3 Aims of the study The present study analyses the surgical treatment of incisional ventral hernias in Finland from 2002–2015, especially focusing on the laparoscopic technique.

The specific aims are:

1. To evaluate the incidence and type of severe complications in adult primary and incisional ventral hernia surgery reported to the national Patient Insurance Centre in Finland from 2003–2010.

2. To evaluate peri- and postoperative outcomes, especially severe complications in incisional ventral hernia repair performed using the open or laparoscopic technique.

3. To compare the efficacy of a hybrid approach versus laparoscopy in reducing the risk of complications related to complex adhesiolysis in incisional ventral hernia repair.

4. To explore the potential benefits of the hybrid over the laparoscopic technique in terms of seroma formation and the risk of enterotomy.

5. To determine whether the hybrid method can diminish hernia recurrence one-year post operation compared to standard laparoscopic hernia repair. As a secondary hypothesis, we evaluated whether the closing of the defect lowers postoperative chronic pain and improves QoL.

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4 Patients and Methods This study was comprised of three patient materials. The study protocols of the retrospective studies (Studies I–III) were approved by the Chief Physician of Oulu University Hospital and the prospective randomised multicentre studies (Studies IV–V) by the local ethical committees of each participating hospital. In each study, data was collected according to the study plan and entered into the IBM SPSS software for statistical analyses.

The material in the first study (Study I) consisted of the claims concerning ventral hernia operations reported to the Finnish National Patient Insurance Centre from 2003–2010. The Finnish Patient Insurance Centre covers the entire country and handles financial compensation for patient injuries without requiring proof of malpractice. Altogether, 127 claims after open or laparoscopic hernia repair of primary and incisional ventral hernias in adult patients were analysed retrospectively. The claims concerned 41 primary and 86 incisional hernioplasties. Major complications, such as fulminant cellulitis, septic and massive SSIs, massive intra-abdominal bleedings, and enterotomies leading to peritonitis, were distinguished from milder complications for analysis. Early complications were noted perioperatively or immediately after the operation and treated during the hospital stay. Late complications appeared after discharging from the hospital during the following weeks or months. The annual number of hernioplasties was acquired from the Finnish Hospital Discharge Register, which gathers information regarding the diagnosis, surgical procedures, dates of admission, and discharge of each patient. Finnish hospitals collect data that is automatically sent to the register maintained by the National Board of Health.

In the second study (Study II), adult patients who underwent an operation for incisional ventral hernias in two tertiary hospitals in Finland (Oulu University Hospital and Central Hospital of Päijät-Häme) during 2006–2012 were included in the study. Clinical data was collected retrospectively from patient registers. Altogether, 818 operations were analysed, and complications from open versus laparoscopic methods were compared, with focus especially on major complications. Patient demographic characteristics, perioperative data, and 30-day outcomes were registered, and Clavien–Dindo grading was used in classifying the complications. Adhesions were classified as severe if they were extremely extensive and/or affected the bowels. To evaluate the possible benefits of laparoscopic operations, an additional analysis between an open group and a

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subgroup of purely laparoscopic operations was performed. The flow chart of the study is shown in Figure 9.

The patient population in the third study (Study III) was a subsample of Study II and comprised of 269 adult patients who underwent elective laparoscopic incisional ventral hernia repair at Oulu University Hospital from 2006–2012. Data was collected retrospectively from the hospital’s patient register. We excluded 18 patients due to their conversion to the open method and 189 patients for not having intense adhesions. Thus, the analysis included all cases with intense serosal adhesions, and a comparison was made between the laparoscopic approach (38 patients) and the hybrid approach (24 patients). Baseline characteristics, as well as peri- and postoperative data, were gathered and analysed. Clavien– Dindo grading (Dindo et al., 2004) was used in classifying the complications. Following Mueller’s classification, the adhesions were graded by severity (Mueller, Tschudi, Herrmann, & Klaiber, 1995):

grade 0 = no adhesions, grade 1 = simple omental adhesions, and grade 2 = intense serosal adhesions.

In the laparoscopic approach, the hernia defect was covered with an intra-peritoneally placed mesh, which was fixed with sutures and absorbable tackers. In the hybrid procedure, adhesions were lysed via a minilaparotomy incision, and the fascial defect was closed before laparoscopic mesh fixation. The flow chart of study III is shown in Figure 10.

The patient populations of the fourth and fifth studies (Studies IV–V) were prospectively gathered as a multicentre co-operation from 11 Finnish hospitals. The 193 adult patients from 2012–2015 undergoing incisional ventral hernia repair were randomly assigned to receive either a conventional laparoscopic mesh repair or a hybrid repair. A separate randomisation list was created via a computer for each participating centre. The randomisation was performed in blocks; the block size varied randomly between 4, 6, and 8.

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Fig.

9. F

low

cha

rt o

f Stu

dy II

.

Exclu

sion:

em

erge

ncy

oper

atio

ns w

ith b

owel

in

carc

erat

ion,

n =

9

Patie

nts w

ith

com

plica

tions

,n

= 79

(18

%)

No

com

plica

tions

, n

= 37

1 (8

2 %

)

Patie

nts w

ith

com

plica

tions

,n

= 9

(22

%)

No

com

plica

tions

,n

= 32

(78

%)

Patie

nts w

ith

com

plica

tions

,n

= 9

(25

%)

No

com

plica

tions

,n

= 27

(75

%)Pa

tient

s with

co

mpl

icatio

n,n

= 68

(23

%)

No

com

plica

tions

,n

= 22

3 (7

7 %

)

Incis

iona

l ven

tral

he

rnio

plas

ties,

n =

827

Lapa

rosc

opic

oper

atio

ns,

n =

450

Conv

ersio

n to

hy

brid

,n

= 41

Conv

ersio

n to

op

en,

n =

36

Lapa

rosc

opica

lly

star

ted

oper

atio

ns,

n =

527

Open

ope

ratio

ns,

n =

291

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Fig.

10.

Flo

w c

hart

of S

tudy

III.

Gr 0

= n

o ad

hesi

ons,

GR

1 =

sim

ple

adhe

sion

s, G

r 2 =

inte

nse

adhe

sion

s.

Lapa

rosc

opic

hern

iopl

astie

s(in

tent

ion-

to-tr

eat)

n =

269

Lapa

rosc

opic

oper

atio

ns, n

= 2

30

•Co

nver

sion

to o

pen,

n =

18

•Gr

0 o

r Gr 1

adh

esio

ns, n

= 1

74

Lapa

rosc

opic

oper

atio

ns w

ith G

r 2 a

dhes

ions

, n

= 38

Hybr

id o

pera

tions

, n =

39

Gr 0

or G

r 1 a

dhes

ions

, n =

15

Hybr

id o

pera

tions

with

Gr 2

adh

esio

ns,

n =

24

Allo

catio

n

Exclu

sion

Stud

y Gro

ups

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We included adult patients with incisional ventral hernias after informed consent was obtained. Exclusion criteria were age ≤ 18 or ≥ 80 years, American Society of Anesthesiologists score (ASA) ≥ 4, body mass index (BMI) ≥ 35, a previous mesh repair, a hernia defect width under 2 cm or over 7 cm, emergency operation, and the impossibility of adequate follow-up.

Perioperatively, surgeons evaluated intra-abdominal adhesions (none, omental, or bowel) and the complexity of adhesiolysis (none, simple, or complex). Blood loss and operative time were recorded, and complications were graded according to the Clavien-Dindo scale (Dindo et al., 2004).

An ultrasound examination was performed preoperatively to measure the hernia defect, one month after surgery to evaluate possible seromas, and after one year to detect recurrent hernias. Seroma was defined as an anechoic fluid collection with a minimum size of 1 cm. The pain score using the visual analog scale (VAS) was registered daily during the patients’ hospital stay and postoperative visits. QoL with SF-36 was gathered at both the pre- and postoperative visits.

In the laparoscopic repair, the Parietex composite mesh® was fixed to the peritoneum with the double crown technique using a Securestrapp® tacking device and four trans-abdominal sutures. The overlap of the mesh was to be at least 5 cm. The hybrid hernia repair method consists of standard laparoscopic repair combined with hernia sack resection and fascial defect closure with slowly absorbable sutures through a mini-laparotomy incision. Preoperative parameters (BMI, smoking, age, ASA) and perioperative details (blood loss, operation time) were registered along with any peri- and postoperative complications.

The results of this study were reported in separate publications: a 30-day outcome and a one-year outcome. The main outcome of the first publication was the number of patients with seroma in a one-month control. The secondary endpoints were peri/postoperative complications and the evaluation of pain (VAS). The primary endpoint in the second publication was hernia recurrence one year after surgery. The secondary measures were long-term complications, pain (VAS), and QoL. The study was approved by the local ethical committee of each hospital and registered in Clinical Trials (NCT02542085). The flow chart of Studies IV and V is shown in Figure 11.

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Fig.

11.

Flo

w c

hart

of S

tudi

es IV

–V.

Recr

uite

d, ra

ndom

ized

(n =

193

)

Lapa

rosc

opic

grou

p (n

= 9

7)•

With

drew

bef

ore

surg

ery

(n =

2)

•Pr

otoc

ol vi

olat

ion

(n =

1)

•her

nia

size

> 7

cm•

Inte

nt to

trea

t (n

= 94

)•

Rece

ived

allo

cate

d in

terv

entio

n (n

= 8

3)•

Did

not r

ecei

ve a

lloca

ted

inte

rven

tion

(n =

11)

•co

nver

sion

to h

ybrid

(n =

8)

•co

nver

sion

to o

pen

(n =

3)

Hybr

id g

roup

(n =

96)

•W

ithdr

ew b

efor

e su

rger

y (n

= 3

)•

Prot

ocol

viol

atio

n (n

= 3

)•a

ge >

80

y•h

erni

a siz

e >

7 cm

•prim

ary

hern

ia•

Inte

nt to

trea

t (n

= 90

)•

Rece

ived

allo

cate

d in

terv

entio

n (n

= 8

7)•

Did

not r

ecei

ve a

lloca

ted

inte

rven

tion

(n =

3)

•la

paro

scop

ic op

erat

ion

(n =

1)

•co

nver

sion

to o

pen

(n =

2)

1-m

onth

ana

lysis

Inte

nt to

trea

t pop

ulat

ion

(n =

94)

1-m

onth

ana

lysis

Inte

nt to

trea

t pop

ulat

ion

(n =

86)

Disc

ontin

ued

prem

atur

ely

(n =

4)

•Lo

st to

follo

w-u

p (n

= 3

)•

Died

from

com

plica

tion

(n =

1)

1-ye

ar a

naly

sisIn

tent

to tr

eat p

opul

atio

n (n

= 9

0)Lo

st to

follo

w-u

p (n

= 4

)

1-ye

ar a

naly

sisIn

tent

to tr

eat p

opul

atio

n (n

= 8

2)Lo

st to

follo

w-u

p (n

= 4

)

Allo

catio

n

Follo

w-u

p

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4.1 Statistical analysis

Summary measurements are presented as the mean with standard deviation or the median with 25th–75th percentiles unless otherwise stated. Between-group comparisons were performed by a χ2 test or Fisher’s exact test (categorical variables) and by Student’s t-test or the Mann-Whitney U-test (continuous variables). Between-group comparisons were performed via a χ2 test or Fisher’s exact test (categorical variables) and by Student’s t-test or the Mann-Whitney U-test (continuous variables) (Studies I–V).

In Study I, age, BMI, method of repair, emergency/elective operation, the use of mesh or sutures in operation, required re-operation, complications distributed as early and late, minor (mild and moderate) or major complications and deaths during hospital stay or within 30 days were included as independent variables. Early complications were those noted perioperatively or immediately after the operation and treated during the hospital stay. Late complications appeared after discharge from the hospital during the following weeks or months.

In Study II, a multivariable adjusted logistic regression model was built to produce an unbiased estimate of the impact of the operative technique on postoperative complications. Age (< 50- vs. ≥ 50- years), size of hernia (< 15 vs. ≥ 15 cm2), having an irreducible hernia, and usage of mesh in an earlier operation were used as adjusting factors. Continuous variables age and the size of hernia were classified due to non-linearity. Odds ratios (ORs) with a 95% confidence interval (95% CI) are presented as the results of the logistic regression model. The area under the receiver operating characteristic (ROC) curve was calculated to explore whether the size of the hernia could predict postoperative complications.

In Studies IV–V, hernia recurrence at one year postoperatively was regarded as a primary endpoint. According to the sample size calculation, assuming a 6% difference (2% in the hybrid group vs. 8% in the laparoscopic group, α = 0.05, power = 0.80, and a drop-out rate of ~20%) in the hernia recurrence rate at the one-year follow-up point, 200 patients per group needed to be randomised. All analyses were done according to the intention to treat (ITT) principle unless otherwise stated. Repeatedly measured continuous variables were analysed using a linear mixed model (LMM), in which patients were selected randomly, and the covariance pattern was chosen according to Akaike’s information criteria. Effect sizes with 95% confidence intervals for a one-year outcome are presented according to LMM.

Two-tailed p < 0.05 was regarded as statistically significant. Analyses were performed via SPSS for Windows (IBM Corp. Released 2012 (2013), IBM SPSS

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Statistics for Windows, Version 21.0 (22.0). Armonk, NY: IBM Corp.), and SAS (version 9.4, SAS Institute Inc., Cary, NC, USA).

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5 Results

5.1 Study I

During the eight-year period, 25 738 ventral hernia operations were performed. Altogether, 127 claims were brought to the Patient Insurance Centre, 41 concerning primary ventral hernia and 86 IVH repairs. The rate of claims was relatively low: 4.9/1000 hernia procedures. There were significantly more claims after incisional hernioplasties compared to after operations for primary hernias (0.9% vs. 0.3% p < 0.001). During the study period, the frequency of laparoscopic operations increased, whereas the number of claims decreased with a significant difference (p < 0.04) (Figure 12). Markedly more claims were reported after laparoscopic operations than open operations (11.6 vs. 4.1/1000 operations, p < 0.001). The four (10%) major complications after primary hernia operations included: one massive bleeding, one bowel perforation, and two severe infections. These complications were related to open repairs. The 15 major complications reported after incisional hernioplasties consisted of twelve bowel perforations with peritonitis and/or severe infection and three massive intra-abdominal bleedings. From these, significantly more occurred during or after laparoscopic procedures than after open operations (0.5% vs. 0.002%, p < 0.001). The distribution of the complications related to IVH repairs is shown in Table 3.

Fig. 12. The frequency of claims after laparoscopic hernioplasties from 2003–2010.

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Table 3. Reported complications concerning IVH operations.

Complication1 Laparoscopic

n = 31

Open

n = 55

P

Immediate complication 23 30 0.11

Pain 2 3 > 0.9

Infection 3 8 0.74

Hematoma 0 3 0.3

Bowel lesion 13 5 0.001

Recurrence 0 3 0.3

Urological injury 1 1 > 0.9

Massive intra-abdominal bleeding 4 1 0.06

Other 1 6 0.71

Late complication 26 49 0.47

Pain 1 3 < 0.9

Infection 8 23 0.16

Hematoma 0 2 0.53

Bowel lesion 5 1 0.02

Recurrence 8 14 > 0.9

Other 2 3 > 0.9

Major complication 13 2 < 0.001

Mortality 1 4 0.65

Financial compensation 19 (61 %) 13 (41 %) 0.001 1 some patients reported several complications

5.2 Study II

In Study II, 818 hernioplasties were evaluated: 291 (36%) open and 527 (64%) laparoscopic operations. The overall complication rate was 20 %. Altogether, 165 patients had 205 complications: 94 (57%) had mild complications (gr 1–2), 58 (35%) moderate complications (gr 3) and 12 (7%) major complications (grades 4–5). The postoperative complication rate was slightly lower in the laparoscopic than in the open group (18% vs. 23%, p = 0.090), with significantly fewer surgical site infections (3% vs. 8%, p = 0.001).

12 major complications occurred, from which five were in the laparoscopic group. From these, four undetected enterotomies occurred during adhesiolysis, leading to major, life-threatening consequences. Three of these patients had an emergency operation resulting in a stoma and recurrent hernia, and one patient died due to peritonitis. Another patient developed abdominal compartment syndrome and died due to multi-organ failure. Major complications in the open group

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consisted of four cardiac infarctions and three septic surgical site infections, causing the death of two patients. Four operation-related deaths were noted: two (0.7%) after open operations and two (0.4%) after laparoscopic operations, leading to an overall mortality of 0.5%.

Adhesiolysis was required in 253 (30.9%) hernioplasties, and, in 93 cases, the adhesions were intense. A third of these patients had complications. Ten out of the 11 enterotomies occurred in operations in which adhesiolysis was described as complex (p < 0.001). In addition to bowel injuries, intense adhesions were related to major complications (5 [5.4%] vs. 7 [1.0%], p = 0.007), emergency operations (7 [7.5%] vs. 20 [2.8%], p = 0.026), and surgical site infections (12 [12.9%] vs. 30 [4.1%], p = 0.001) compared to operations, in which adhesiolysis was easy or not required.

The mean blood loss and hospital stay were significantly lower in the laparoscopic group than the open group. In the open group, there were significantly more immediate reoperations compared to the laparoscopic group: 11 surgical site infection-related revisions, three hematoma evacuations, one resuturation of wound dehiscence, and one operation for massive pulmonary embolus. In the laparoscopic group, the 11 instant reoperations were due to four undetected bowel injuries, two surgical site infections, three wound bleedings, one cardiac bypass and one cystoscopy. These outcomes are shown in Table 4.

Table 4. Outcomes of open and laparoscopic operations.

Parameters Open operations,

n = 291

Laparoscopically

started operations,

n = 527

p Laparoscopic

operations¹,

n = 450

p

Duration min,

mean ± SD3 (range)2

121 ± 83 (18–540) 105 ± 52.2 (26–278) 0.093 93 ± 48.2 (26–278) 0.003

Blood loss ml,

mean ± SD (range)2

32 ± 78 (0–500) 13 ± 36 (0–300) 0.028 6 ± 17 (0–150) 0.003

Reoperation, n (%) 16 (5.5) 11 (2.1) 0.013 10 (2.2) 0.018

Hospital stay days,

mean ± SD (range)

6 ± 9 (1–98) 4 ± 4 (1–69) < 0.001 4 ± 4 (1–69) < 0.001

¹ Laparoscopic subgroup, in which hybrid operations and conversions to open are excluded, 2 Data

collected from Oulu University Hospital, total n = 416, 3 standard deviation

Irreducible hernias were significantly more frequent in the open group and were associated with enterotomies (5 [4.3%] vs. 6 [0.9%], p = 0.012), cardiac complications (5 [4.3%] vs. 7 [1.0%], p = 0.018), and major complications

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(9 [7.8%] vs. 3 [0.4%], p < 0.001) when compared to the operations performed for reducible hernias.

The summary of complications is shown in Table 5.

Table 5. Overall complications.

Parameters Open

operations,

n = 291

Laparoscopically

started

operations,

n = 527

p Laparoscopic

operations2,

n = 450

p

Patients with complications1 n (%) 68 (23.4) 97 (18.4) 0.090 79 (17.6) 0.053

Enterotomy, n (%) 2 (0.7) 9 (1.7) 0.34 5 (1) 0.71

undetected, n (%) 0 4 (0.8) 0.14 4 (0.8) 0.16

Surgical site infection, n (%) 25 (8.6) 17 (3.2) 0.001 12 (2.7) < 0.001

Seroma/hematoma, n (%) 20 (6.9) 28 (5.3) 0.36 19 (4.2) 0.13

Ileus/obstruction, n (%) 5 (1.7) 15 (2.8) 0.32 12 (2.7) 0.46

Cardiac complication, n (%) 8 (2.7) 4 (0.8) 0.032 4 (0.9) 0.071

Pneumonia, n (%) 4 (1.4) 10 (1.9) 0.78 6 (1.3) > 0.90

Wound dehiscence, n (%) 2 (0.7) 1 (0.2) 0.29 1 (0.2) 0.57

Pulmonary embolus, n (%) 2 (0.7) 2 (0.4) 0.62 2 (0.4) 0.65

Urinary tract infection, n (%) 2 (0.7) 3 (0.6) 0.3 3 (0.6) 0.33

Wound bleeding, n (%) 1 (0.3) 3 (0.6) > 0.90 2 (0.4) > 0.90

Miscellaneous, n (%) 4 (1.4) 8 (1.5) > 0.90 7 (1.6) > 0.90

Immediate recurrence3, n (%) 8 (2.7) 22 (4.2) 0.3 20 (4.4) 0.32

Major complications, n (%) 7 (2.4) 5 (0.9) 0.09 5 (1.1) 0.23

Mortality, n (%) 2 (0.7) 2 (0.4) 0.62 2 (0.4) 0.65 1 Some patients had more than one complication, 2 Laparoscopic subgroup, in which hybrid operations

and conversions to open are excluded, 3 Recurrences during the hospital stay

5.3 Study III

In Study III, among the 269 hernia operations, there were 38 laparoscopic and 24 hybrid procedures related to complex adhesiolysis, which were therefore analysed. The complication rate in the laparoscopic group was 28.9% and 25% in the hybrid group. In the laparoscopic group, 11 patients had postoperative complications, from which mild (gr 1–2) 15.8%, moderate (gr 3) 2.6% and major (gr 4–5) 10.5%. All four major complications were due to undetected enterotomies and led to severe complications: bowel resections and surgical site infections. One patient died from septic shock. In the hybrid group, there were no major (gr 4–5) complications, but six (25%) patients suffered from mild (gr 1–2) and moderate (gr 3) complications.

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None of the patients died following surgery. Four bowel injuries occurred during adhesiolysis at the time of the minilaparotomy of unplanned hybrid procedures. These were sutured immediately and not associated with any complications. Table 6 summarises the postoperative outcome in the study groups. Blood loss was significantly higher in the hybrid group (p = 0.036), but its amount was clinically negligible, and these patients did not require blood transfusion.

Table 6. Distribution of complications, peri- and postoperative outcomes in patients undergoing incisional ventral hernia repair via laparoscopic and hybrid approaches.

Postoperative adverse events Laparoscopic group

n = 38

Hybrid group

n = 24

p

Patients with complications1 11 (28.9) 6 (25) 0.73

Bowel injury 5 (13.2) 4 (16.7) 0.73

Undetected bowel injury 4 (10.5) 0 0.15

Seroma 6 (15.8) 4 (16.7) > 0.9

Surgical site infection 3 (7.9) 1 (4.2) > 0.9

Ileus/obstruction 1 (2.6) 2 (8.3) 0.55

Pneumonia 1 (2.6) 1 (4.2) > 0.9

Urinary tract infection 1 (2.6) 0 > 0.9

Operative time (min) 128 ± 57 134 ± 38 0.65

Blood loss (ml) 0 (0–0) 0 (0–45) 0.036

Reoperation 4 (10.5) 0 0.15

Hospital stay (days) 4 (3–5) 5 (4–6) 0.22

Hospital mortality 1 (2.6) 0 > 0.9 1 Some patients suffered from more than one complication, as defined by the Dindo–Clavien

classification, continuous variables are reported as mean ± SD or median and 25–75th percentiles,

categorical variables are reported as counts and percentages (in parentheses).

5.4 Study IV–V

In Study IV, a total of 193 patients consented to randomisation from December 2012 to May 2016; 97 were assigned to the laparoscopic group and 96 to the hybrid group. From these, 94 patients in the laparoscopic and 90 in the hybrid group were operated on and analysed. Baseline clinical characteristics were similar among the study groups, and the operative outcomes did not differ between the groups. In the laparoscopic group, the adhesiolysis was clearly more often described as complex than in the hybrid group. When comparing complex adhesiolysis cases only, the difference between the operative groups was significant (p = 0.028). Of the laparoscopic operations, eight were converted to hybrid, four cases were due to

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intense bowel adhesions, and four cases involved an enterotomy during the laparoscopic phase. Three operations were converted to open after complex adhesiolysis and one involved an enterotomy. All these bowel injuries were managed immediately with no further complications. In the hybrid group, one operation was performed laparoscopically, and two were converted to open due to extensive adhesions. The conversion rates were 3.2% in the laparoscopic and 2.2% in the hybrid group.

The postoperative complication rate was rather low: 15 (16%) patients in the laparoscopic and 11 (12.2%) patients in the hybrid group had postoperative complications. On the first postoperative day, pain scores were significantly higher in the hybrid group than in the laparoscopic group (4.3 vs. 5.2, p = 0.019). Clearly, more patients undergoing laparoscopic operations were readmitted to the hospital due to pain. During the 30-day postoperative period, five reoperations were performed. In the laparoscopic group, one patient had a reoperation due to pain and high C-reactive protein levels. A partially necrotic omentum was resected. The other four operations were reported from the hybrid group. Due to intra-abdominal infection, one mesh was removed. A patient with a wound infection received vacuum-assisted therapy, and the wound was covered with a skin graft. In one reoperation performed due to intensive pain, a transfascial suture was entangled with a subcutaneous nerve and had to be removed, which relieved the pain afterwards. In this study, six bowel injuries occurred, with one in the hybrid group remaining unnoticed. Regardless of a reoperation on the third postoperative day and an open abdomen treatment in the intensive care unit, this patient suffered from multi-organ failure and succumbed to death, leading to a mortality rate of 0.5%. The 30-day outcome is shown in Table 7.

One-month outcome

Data from the one-month follow-up was not available for four patients in the hybrid group. Three patients did not attend, and one patient had died due to a complication. At the time of the one-month follow-up visit 47/94 (50%) patients in the laparoscopic group and 34/86 (39.5%) patients in the hybrid group had some symptoms (p = 0.179). There was also clearly more seroma formation in the laparoscopic group than in the hybrid group (63 [67%] vs. 39 [45.3%], p = 0.004). The seromas in the laparoscopic group were significantly larger, and six seromas were punctured. Half of these postoperative seromas—31 in the laparoscopic group

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and 19 in the hybrid group—can be graded as complications according to the Morales-Conde classification (Morales-Conde, 2012). The outcomes of the one-month follow-up are shown in Table 8.

Table 7. 30-day outcome after laparoscopic and hybrid operations.

Outcome Laparoscopic group

n = 94

Hybrid group

n = 90

p

In-hospital mortality 0 1 (1.1) 0.31

In-hospital stay (days), mean (SD) 2.4 (SD 1.9) 3.1 (SD 3.2) 0.090

Pain severity (VAS), mean (SD)

1st postop day1 4.3 (SD 2.37) 5.2 (SD 2.57) 0.019

2nd postop day2 4.5 (SD 2.46) 5.2 (SD 2.27) 0.16

3rd postop day3 4.3 (SD 2.73) 5 (SD 2.36) 0.29

Readmission due to pain 13 (13.8) 3 (3.3) 0.017

Postoperative complications, n (%)4

Wound infection 2 (2.1) 3 (3.3) 0.62

Wound dehiscence 0 1 (1.1) 0.31

Intra-abdominal infection 1 (1.1) 1 (1.1) 0.090

Seroma 3 (3.2) 3 (3.3) 0.96

Hematoma 4 (4.3) 4 (4.4) 0.95

Myocardial ischemia 1 (1.1) 0 0.33

Pneumonia 2 (2.1) 1 (1.1) 0.59

Pulmonal embolus 0 1 (1.1) 0.31

Intestinal obstruction 4 (4.3) 2 (2.2) 0.44

Urinary tract infection 3 (3.2) 1 (1.1) 0.62

Urinary retention 1 (1.1) 0 0.49

Clavien-Dindo grading, n (%) 0.45

No complication 79 (84) 79 (87.8)

gr 1 4 (4.3) 4 (4.4)

gr 2 10 (10.6) 4 (4.4)

gr 3 1 (1.1) 3 (3.3)

gr 4 0 0

gr 5 0 1 (1.1)

Reoperation, n (%) 1 (1.1) 4 (4.4) 0.16

¹ data from 178 out of 184 patients (laparoscopic group 94, hybrid group 88), ² data from 114 out of 124

patients (laparoscopic group 55, hybrid 59), ³ data from 62 out of 87 patients (laparoscopic group 29,

hybrid 33), 4 some patients had more than one complication. Nominal variables are reported as counts

and percentages (in parentheses); continuous variables are reported as mean and standard deviation;

pain severity was estimated via the VAS score, ranging from 1 to 10.

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Table 8. One-month outcomes after laparoscopic and hybrid operations.

Outcome Laparoscopic group

n = 94

Hybrid group

n = 86

p

Symptoms, n (%)

None 47 (50) 52 (60.5) 0.18

Movement restrictions 39 (42.4) 29 (34.1) 0.28

Pain 32 (34.4) 25 (29.8) 0.52

VAS1, mean (SD) 2.19 (1.84) 2.22 (1.51) > 0.9

Clinical findings, n (%)

Wound infection 1 (1.1) 1 (1.2) > 0.9

Seroma 46 (48.9) 27 (31.4) 0.022

Radiological findings

Seroma 63 (67) 39 (45.3) 0.004

Seroma puncture 6 (6.4) 0 0.017

Seroma size, cm³, median (25th–75th) 162 (30–388) 50 (13–145) 0.025

[min–max] [2–8495] [0.1–670] 1 visual analogue scale, pain severity was estimated by the VAS scale, ranging from 1 to 10. Nominal

variables are reported as counts and percentages (in parentheses); continuous variables are reported as

the mean plus standard deviation.

One-year outcome

There was no difference in hernia recurrence between the study groups upon the one-year follow-up visit. Radiologically, 11 recurrent hernias were detected, resulting in a recurrence rate of 6.4% (11/172): six (6.7%) in the laparoscopic group and five (6.1%) in the hybrid group. A re-hernioplasty was planned for two patients; the others were asymptomatic and continued with conservative care. We found no specific predicting or predisposing factors related to hernia recurrence in either the patient-related factors or peri- or postoperative data. The outcomes of the one-year visit are shown in Table 9.

Compared to patients in the laparoscopic group, the patients who had undergone hybrid repair were more asymptomatic [74/90 (82%) vs. 76/82 (93%)] and suffered less from chronic pain [12/90 (13%) vs. 4/82 (5%)]; however, this was not a statistically significant difference. Generally, patients were satisfied with the cosmetic results after their operations: on a scale from 1 (totally dissatisfied) to 10 (totally satisfied), the mean value in both groups was 9.

The QoL questionnaires were gathered at three points: preoperatively and at one-month and one-year visits. The main finding was that the operative treatment of hernias, both laparoscopic and hybrid, significantly improved patients’ QoL

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when comparing the preoperative period to one-year post operation. In particular, scores in physical functioning increased by 4.3 points (p = 0.014) and bodily pain scores by 7.8 points (p < 0.001) during the follow-up period. The patients in the hybrid group reported markedly less pain before their hernia repair compared to those in the laparoscopic group, and this difference remained after one year. Otherwise, no differences between the operative groups were seen. The pain scores one-year post operation were very low in both groups: the mean VAS was 1.5 in the laparoscopic group and 1.4 in the hybrid group (p = 0.5). Figures 13–20 show the SF-36 scores throughout the study period.

Table 9. One-year outcome.

Outcome Laparoscopic

group

n = 90

Hybrid group

n = 82

Difference1 95% CI for the

difference

p

Symptoms, n (%)

None 74 (82) 76 (93) -10.5 -20.4 to -0.3 0.066

Bulging 6 (7) 4 (5) 1.8 -6.1 to 9.5 0.7

Pain 12 (13) 4 (5) 8.5 -0.5 to 17.5 0.07

VAS2, mean (SD) 1.5 (1.2) 1.4 (1.1) 0.1 -0.2 to 0.5 0.5

Clinical findings, n (%)

Palpable mass 22 (24) 12 (16) 8.6 -3.6 to 20.3 0.19

Recurrent hernia 4 (5) 3 (4) 0.8 -6.3 to 7.7 > 0.99

Radiological findings

Hematoma/seroma 12 (13) 5 (6) 7.2 -2.0 to 16.5 0.13

Hernia sack remnant 7 (8) 3 (4) 4.1 -3.5 to 11.9 0.34

Recurrent hernia confirmed 6 (7) 5 (6) 0.6 -7.6 to 8.5 > 0.99

Re-hernioplasty 1 (1) 1 (1) 0.1 -5.6 to 4.9 > 0.99

Cosmetic evaluation, mean (SD) 8.8 (1.5) 8.9 (1.6) -0.08 -0.55 to 0.39 0.74 1 Difference in percentage units, 2 visual analogue scale; pain severity was estimated by the VAS scale,

ranging from 1 to 10. Nominal variables are reported as counts and percentages (in parentheses);

continuous variables are reported as the mean plus standard deviation.

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Fig. 13. SF-36 score, physical functioning preoperatively, one-month, and one-year after operation.

Fig. 14. SF-36 score, bodily pain preoperatively, one-month, and one-year after operation.

0 1 11 120

10

20

30

40

50

60

70

80

90

100

SF-3

6, P

hysi

cal F

unct

ioni

ng

Time, months

Hybrid Laparoscopic

Ptime < 0.001Pgroup = 0.73Ptime x group = 0.86

0 1 11 120

10

20

30

40

50

60

70

80

90

100

SF-3

6, B

odily

Pai

n

Time, months

Hybrid Laparoscopic

Ptime < 0.001Pgroup = 0.020Ptime x group = 0.38

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Fig. 15. SF-36 score, role physical preoperatively, one-month, and one-year after operation.

Fig. 16. SF-36 score, general health preoperatively, one-month, and one-year after operation.

0 1 11 12

0

10

20

30

40

50

60

70

80

90

100

SF-3

6, R

ole

Phys

ical

Time, months

Hybrid Laparoscopic

Ptime < 0.001Pgroup = 0.43Ptime x group = 0.10

0 1 11 12

0

10

20

30

40

50

60

70

80

90

100

SF-3

6, G

ener

al h

ealth

Time, months

Hybrid Laparoscopic

Ptime = 0.31Pgroup = 0.76Ptime x group = 0.47

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Fig. 17. SF-36 score, vitality preoperatively, one-month, and one-year after operation.

Fig. 18. SF-36 score, social functioning preoperatively, one-month, and one-year after operation.

0 1 11 12

0

10

20

30

40

50

60

70

80

90

100

SF-3

6, V

italit

y

Time, months

Hybrid Laparoscopic

Ptime = 0.073Pgroup = 0.59Ptime x group = 0.53

0 1 11 120

10

20

30

40

50

60

70

80

90

100

SF-3

6, S

ocia

l fun

ctio

ning

Time, months

Hybrid Laparoscopic

Ptime = 0.004Pgroup = 0.50Ptime x group = 0.076

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Fig. 19. SF-36 score, role emotional preoperatively, one-month, and one-year after operation.

Fig. 20. SF-36 score, mental health preoperatively, one-month, and one-year after operation.

0 1 11 12

0

10

20

30

40

50

60

70

80

90

100

SF-3

6, R

ole

Emot

iona

l

Time, months

Hybrid Laparoscopic

Ptime = 0.010Pgroup = 0.85Ptime x group = 0.36

0 1 11 120

10

20

30

40

50

60

70

80

90

100

SF-3

6, M

enta

l hea

lth

Time, months

Hybrid Laparoscopic

Ptime = 0.056Pgroup > 0.90Ptime x group = 0.18

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6 Discussion The aim of the study was to compare the IVH repair results of different operative techniques, with primary focus on the severe threads related to laparoscopic operations and exploring opportunities to avoid or diminish these problems using a hybrid hernia repair technique.

In Study I, we introduced the main issues concerning hernia repair on a national level by publishing claims concerning complications that occurred in hernia repair operations from 2003–2010. With our two other retrospective Studies II and III, the comparative results of open, laparoscopic, and hybrid methods were shown. Since the 90s, laparoscopy has gained popularity as a mini-invasive operative method, and it has also become routinely used in hernia repair. A known concern related to this hernia repair method is the occurrence of enterotomy, which can stay undetected during laparoscopy (LeBlanc et al., 2007). Adhesiolysis carries a risk of bowel lesions (Gray et al., 2008; ten Broek et al., 2012). Another drawback has been the hernia recurrence rate, which has not improved with the laparoscopic technique (Al Chalabi et al., 2015; Pring, Tran, O'Rourke, & Martin, 2008). In the last decade, a rather new technique, the hybrid, has shown more promising outcomes (Banerjee et al., 2012; Chelala et al., 2015; Orenstein et al., 2011; Suwa, Okamoto, & Yanaga, 2016).

When planning this dissertation in 2012, a basic laparoscopic hernia repair method was in routine use. However, the risks of this laparoscopic technique were noted, and a search for a safer method with a lower recurrence outcome was needed. At that time, there were some publications presenting promising results of a new technique, called IPOM plus or hybrid, in which laparoscopic mesh repair was combined with fascial defect closure. To explore the possibility of diminishing the risk of perioperative enterotomy and hernia recurrence using a hybrid technique, we created a randomised prospective multicentre trial including 11 hospitals with a high volume of hernia operations. It is important to note that there have been no previous randomised controlled trials comparing laparoscopic and hybrid techniques. The perioperative and short-term results are shown in Study IV and the one-year results in Study V.

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6.1 Discussion of the main results

6.1.1 Comparison between the outcomes of operative techniques in Studies IV–V

The peri- and postoperative outcomes were compared between the operative groups. No differences in operative time or blood loss were found, and even the adhesiolysis was described as clearly more often complex in laparoscopic operations. During the 30-day postoperative period, there were only five (2.7%) reoperations, with no significant differences found between the groups. These findings are in line with a recent study (Bernardi et al., 2019). Clearly, a greater number of patients from the laparoscopic group required readmission to the hospital when compared to patients in the hybrid group. The mortality rate of 0.5% was comparable to that of previous results (Khorgami, Hui, Mushtaq, Chow, & Sclabas, 2019).

6.1.2 Enterotomy

In all studies included in this thesis, laparoscopic operations were found to carry a risk for enterotomy. In Study I, the major complications reported after laparoscopic operations were mostly due to enterotomies that led to severe infections and reoperations. A similar finding was seen in a recent study concerning claims to the Swedish National Patient Insurance Company (Lindmark, Strigard, Nordin, & Gunnarsson, 2018). All major complications of the laparoscopic operations in Studies II–III were consequences of bowel injuries. A clear correlation between intense adhesions and risk of enterotomy was observed, which is in line with previous studies (Perrone et al., 2005; ten Broek et al., 2012). Based on this, converting a laparoscopic operation into a hybrid could be recommended in cases with complex adhesiolysis. In Study IV, 11 laparoscopic operations were converted to open or hybrid due to intense adhesions and five enterotomies. Only one enterotomy was left undetected. This occurred in the hybrid group, introducing the first trocar into the abdomen and being far from the operative area, it remained unnoticed. Lysing intense adhesions was reported as markedly less complex hand-assisted than laparoscopically. According to our findings, adhesiolysis through a minimally invasive incision seemed to be easier and associated with a lower risk of leaving an adhesiolysis-related undetected and, therefore, untreated bowel

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iatrogenic injury. This supports our hypothesis that the hybrid technique may be a valid minimally invasive approach in cases involving bowel adhesions.

6.1.3 Seroma formation

A seroma is known as one of the most common findings following laparoscopic hernia repair with unclear clinical relevance. Its incidence varies greatly among the studies and can be as high as 100% after laparoscopic operations (Susmallian, Gewurtz, Ezri, & Charuzi, 2001). According to Morales-Conde’s seroma definition, seromas lasting last over six months or those that are symptomatic or infected are considered complications (Morales-Conde, 2012). An infection of a seroma can lead to serious adverse events, such as mesh infection and hernia recurrence (Banerjee et al., 2012; Sodergren & Swift, 2010). In Studies II and III, retrospectively gathered data showed no difference between laparoscopic and hybrid operations in terms of seroma formation. The incidence of reported seromas was relatively low (5–6%). In our multicentre Studies IV–V, we wanted to explore the effect of hernia sack resection and fascial defect closure with postoperative seroma formation. An ultrasound examination was used in evaluating seromas. Supporting our hypothesis, we found that there are significantly more and larger seromas following laparoscopic rather than hybrid operations (67% vs. 45%). Still, the number of clinically relevant seromas, which are considered complications, was clearly lower in both groups.

6.1.4 Hernia recurrence

Hernia recurrence is still a problem, as laparoscopic hernia repair has not clearly overcome the recurrence rates of the open method (Sauerland et al., 2011). In Study I, one third of claims concerned hernia recurrence. For Studies II and III, no reliable recurrence data could be gathered due to the retrospective nature of the studies and a lack of follow-up. The main aim of our randomized Studies IV–V was to explore whether postoperative seroma formation and, therefore, hernia recurrence could be diminished by closing the hernia defect. Our follow-up timepoint for hernia recurrence was one year after operation. There were six recurrent hernias in the laparoscopic group and five in the hybrid group that were confirmed radiologically, producing a recurrence rate of 6.4%. The results showed no difference between the operative groups. According to recent studies, fascial closure combined with IPOM repair leads to recurrence rates as low as 0.0–4.8% (Banerjee et al., 2012; Chelala

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et al., 2015; Stoikes et al., 2013). In only one of these studies (Chelala et al., 2015), hernia recurrence was evaluated using computed tomographic scans and findings from second-look laparoscopies (Chelala et al., 2010). Others were retrospective or descriptive analyses. A common problem, bulging related to IPOM repair, can manifest as a pseudo-recurrence and therefore mimic a recurrent hernia without radiological confirmation (Tse et al., 2010). According to the literature, most hernia recurrences occur during the first two to three years following repair (Kokotovic et al., 2016; Yoo et al., 2018). From this perspective, a one-year follow-up is rather short. One patient from both groups underwent a re-hernioplasty; others with recurrent hernias were asymptomatic and continued with conservative care. Thus, it can be highlighted that the clinically relevant hernia recurrence rate in the laparoscopic group was 1.1%, 1.2%, in the hybrid group, and 1.2% amongst all study patients.

Recently, a Danish study concluded that mesh fixation with permanent fixation material combined with defect closure has a clear influence on the cumulative risk of hernia recurrence without raising chronic pain rates when compared to fixation with absorbable tackers (Christoffersen et al., 2015). In our study, mesh fixation was performed using absorbable tacks, and it can be speculated whether this could have affected the recurrence rate in general.

6.1.5 Pain

According to the literature, up to 25% of patients suffer from chronic pain following a hernia operation (Kockerling et al., 2019; Liot et al., 2017). After laparoscopic hernioplasties, the incidence of chronic pain ranges between 1.3–14.7% (Cocozza et al., 2014; Heniford et al., 2003; Sharma et al., 2011; Bittner et al., 2014c). In our analysis in Studies IV–V, pain scores during hospital stay were similar between study groups except for the first postoperative day, in which patients having a hybrid repair suffered from more intense pain than patients who had a laparoscopic operation (VAS: 5.2 vs. 4.3, p = 0.019). Still, clearly more patients undergoing laparoscopic operations returned to the hospital due to pain within 30 days following surgery (13% vs. 3%, p = 0.017). Of these, pain was related to seroma formation in nine cases, and in two cases it was caused by a transabdominal suture, with the other two cases remaining unexplained. All these patients were treated conservatively except for one patient, whose transabdominal suture causing intensive pain was removed upon reoperation. One year after their operative treatment, more patients from the laparoscopic group suffered from chronic pain

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compared to patients from the hybrid group (13% vs. 5%, p = 0.07). The mean VAS was low in both groups (1.5 vs. 1.4). According to the literature review of IEHS, the method used for mesh fixation (sutures and/or tacks) has no influence on acute postoperative pain (Bittner et al., 2014). It is also suggested that a tension-free fascial defect closure can lower the risk of chronic pain (Chelala et al., 2015; Gomez-Menchero et al., 2018). According to our findings, it is safe to say that most patients after hernioplasty seemed to be pain-free, especially when the defect was closed and the anatomical and functional structure of the abdominal wall restored.

6.1.6 QoL

IVH occurrence has a significant impact on health-related QoL and body image. In a prospective cohort study of 967 patients undergoing operations, those with an IVH reported lower health-related QoL on the physical components and worse body image than patients without a hernia (van Ramshorst et al., 2012). According to our findings, after hernia repair, the scores improved in all categories of SF-36, except for general health. During the first month, physical function measures and pain scores mildly deteriorated, which is presumably related to the recovery phase following surgery. One year after surgery, improvement was obvious. No difference between laparoscopic and hybrid repair was seen in our randomised study. A similar result was found in a recent study comparing hybrid and laparoscopic hernia operation in terms of QoL (Saijo et al., 2019). The results showed that, in general, hernia repair improves patient QoL, which is in line with other studies (Langbach et al., 2016; Rogmark et al., 2016).

6.2 Limitations of the thesis

The first two studies of this thesis were retrospective. In Study I, the data was gathered from the register of the Patient Insurance Centre and consisted of reported claims with a small sample size. Therefore, the material is descriptive and reflects only a minor portion of all the complications that occurred during the study period. In Study III, the patient material was prospectively recorded, but, as in Study II, the postoperative data were retrospectively gathered. In these studies, there was no follow-up data. In Study III, the sample sizes of the subgroups under comparison were small. In our prospective Studies IV and V, the main drawback was the failure to reach the estimated sample size of 400 patients, even with prolonged recruitment time. As the hybrid method gained popularity during the study period and was

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recommended by the IEHS guidelines (Bittner et al., 2014a), surgeons became less enthusiastic in recruiting patients to the study. Furthermore, we did not have a complete screening log from all the centres involved in the study, which may have led to selection bias. The follow-up time of one year was rather short, and, therefore, the follow-up for these study patients will continue up to five years.

6.3 Clinical importance

The laparoscopic technique is in routine use in hernia surgery. The results of this thesis highlight the increased risk of enterotomy, especially in cases complicated by bowel adhesions. Our study shows that lysing adhesions hand-assisted is a safe and feasible method. In addition, bulging and seroma formation are diminished due to defect closure. In summary, the hybrid method combines the benefits of laparoscopic and mini-invasive open techniques with a lower risk of enterotomy.

6.4 Future expectations

Hernia surgery is a fast-advancing field of surgery, and several new methods have been presented during the last few years.

The known problems related to intra-peritoneally placed mesh are adhesions and mesh shrinkage. A new kind of mesh with absorbability and neoperitonealisation could solve these problems. Otherwise, there is a tendency towards mini-invasive methods, in which the mesh is placed between the abdominal wall layers to avoid intraperitoneal dissection (Bittner et al., 2019b). Overall, long-term results will point us in the right direction in hernia surgery.

Although hernioplasties are common operations performed in almost all primary, secondary, and tertiary hospitals, it should be noted that routine and experience of surgeons significantly influence surgical outcomes. A recent study demonstrated that abdominal wall experts see better results in hernia surgery than other surgeons (Pereira et al., 2019). Thus, hernioplasties should be performed by experienced specialists.

The most reliable evidence-based data comes from randomised controlled trials and meta-analyses; however, there are still clinically important questions that cannot be addressed in the context of a randomised trial. In these cases, observational studies can offer an opportunity to evaluate the outcomes of surgical treatments. There are few nationwide prospective registries in which clinical data is systematically collected. In 2016, a CORE project listed all hernia registries

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established thus far: Danish Hernia Database, Swedish Hernia Registry, Herniamed, EuraHS, Club Hernie, EVEREG, and AHSQC (Kyle-Leinhase et al., 2018). Except for the Danish registry, participation in data collection is voluntary. Thus, the completeness of data depends on the participating surgeons and hospitals. The Finnish Hernia Society was established in November 2017 and became a part of the European Hernia Society in 2018. Specifically, Finland has a national hernia registry program that has the potential to create an extensive hernia surgery database and therefore serve as an important resource for similar clinical research other Nordic countries.

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7 Conclusions

On the basis of the present study, the following conclusions can be made:

1. According to the claims reported to the Patient Insurance Centre, complications related to ventral hernia repair seem to be quite uncommon and tolerable. Major complications are rare but significantly more frequent following laparoscopic rather than open operations.

2. We conclude that open hernioplasties were associated more often with postoperative complications, particularly surgical site infections, when compared to laparoscopic surgery. Still laparoscopic hernia surgery is related to risk of undetected enterotomies and therefore severe consequences, especially in cases featuring complex adhesions.

3. We found that adhesiolysis, through a minimally invasive open technique, the hybrid technique, may be associated with a lower risk of bowel iatrogenic injuries potentially occurring in operations with complex adhesions. This indicates that the hybrid technique may be a valid minimally invasive approach incorporating the benefits of laparoscopy and reducing the risk of bowel injury.

4. We conclude that the hybrid technique, in which the hernia sack is resected and the fascial defect closed, carries a low risk of enterotomy and is associated with clearly diminished seroma formation when compared to basic laparoscopic hernia repair.

5. The results showed that standard laparoscopic hernia repair and the hybrid method both had a low hernia recurrence rate one year post operation. Long-term follow-up is needed to demonstrate the potential advantage of the hybrid operation in terms of fascial defect closure. Overall, laparoscopic and hybrid hernia repair techniques improve patients’ QoL and reduce chronic pain incidence significantly.

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Original publications This thesis is based on the following publications:

I Ahonen-Siirtola, M., Vironen, J., Mäkelä, J., & Paajanen, H. (2014). Surgery-related complications of ventral hernia reported to the Finnish Patient Insurance Centre. Scandinavian Journal of Surgery, 104(2), 66–71. https://doi.org/10.1177/14574969 14534208

II Ahonen-Siirtola, M., Rautio, T., Ward, J., Kössi, J., Ohtonen, P., & Mäkelä, J. (2015). Complications in laparoscopic versus open incisional ventral hernia repair. A retrospective comparative study. World J Surg, 39(12), 2872–2877. https://doi.org/ 10.1007/s00268-015-3210-6

III Ahonen-Siirtola, M., Rautio, T., Biancari, F., Ohtonen, P., Mäkelä, J. (2017). Laparoscopic versus Hybrid Approach for Treatment of Incisional Ventral Hernia. Dig Surg, 34(6), 502–506. https://doi.org/10.1159/000458713

IV Ahonen-Siirtola, M., Nevala, T., Vironen, J., Kössi, J., Pinta, T., Niemeläinen, S., Keränen, U., Ward, J., Vento, P., Karvonen, J., Ohtonen, P., Mäkelä, J., Rautio, T. (2018). Laparoscopic versus hybrid approach for treatment of incisional ventral hernia: a prospective randomized multicenter study of 1-month follow-up results. Hernia, 22(6), 1015–1022. https://doi.org/10.1007/s10029-018-1784-2

V Ahonen-Siirtola, M., Nevala, T., Vironen, J., Kössi, J., Pinta, T., Niemeläinen, S., Keränen, U., Ward, J., Vento, P., Karvonen, J., Ohtonen, P., Mäkelä, J., Rautio, T. (2019). Laparoscopic versus hybrid approach for treatment of incisional ventral hernia: a prospective randomised multicentre study, 1-year results. Surg Endosc. 2019 Apr 2. https://doi.org/10.1007/s00464-019-06735-9 [Epub ahead of print]

The original publications have been reproduced with the kind permission of the copyright holders SAGE publications (I), Springer Nature (II), Karger Publishers (III), Springer Nature (IV), Springer Nature (V).

Original publications are not included in the electronic version of the dissertation.

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