Il monitoraggio nervoso Il monitoraggio nervoso

intraoperatoriointraoperatorio

Gianlorenzo Dionigi, MD, FACSGianlorenzo Dionigi, MD, FACS

Department of Surgical SciencesDepartment of Surgical Sciences

UNIVERSITY OF INSUBRIA (COMO – VARESE) - ITALYUNIVERSITY OF INSUBRIA (COMO – VARESE) - ITALY

Il Linfonodo Sentinella in Chirurgia: Attualità e ProspettiveIl Linfonodo Sentinella in Chirurgia: Attualità e ProspettiveDirettore: Prof. A. LiboniDirettore: Prof. A. Liboni

20 gennaio 2012 20 gennaio 2012 Ferrara, ITALYFerrara, ITALY

This report does not endorse any This report does not endorse any specific Company or set of specific Company or set of

monitoring equipment monitoring equipment

Exposure of RLN reduce the rate of Exposure of RLN reduce the rate of

RLN injuryRLN injury

Lahey FH, Lahey FH, Ann Surg 1938Ann Surg 1938 1.61.6 0.3 0.3

Riddell VH, Riddell VH, Lancet 1956Lancet 1956 3.53.5 2.1 2.1

Jazko, Jazko, Surgery 1994Surgery 1994 7.97.9%% 1.2 1.2%%

Wagner, Wagner, Br J Surg 1994Br J Surg 1994 2121%% 6.9 6.9%% - - --

Hermann, Hermann, Ann Surg, 2002Ann Surg, 2002 2.12.1%% 0.90.9%% 0.3 0.3%% 0.1 0.1%%

Dralle H, Dralle H, Surgery 2004Surgery 2004 1.161.16%% 0.63 0.63%%

Chiang, Chiang, Surgery 2005Surgery 2005 5.15.1%% 0.9 0.9%% - - --

Localized Localized RLN RLN

Partially exposedPartially exposedRLN RLN

Completely dissected Completely dissected RLN RLN

No identificationNo identificationRLN RLN

Gold standards for RLN management Gold standards for RLN management

1.1. Extensive knowledge of RLN anatomyExtensive knowledge of RLN anatomy

2.2. Visual identification of RLNVisual identification of RLN

3.3. Exposure of RLNExposure of RLN

4.4. Experience & trainingExperience & training

5.5. Pre- & post-op. laryngoscopyPre- & post-op. laryngoscopy

RLN and laryngeal anatomy are the RLN and laryngeal anatomy are the

basis of modern thyroid surgerybasis of modern thyroid surgery

Why do we need more Why do we need more

than anatomical nerve identification?than anatomical nerve identification?

Why Why neuromonitoring?neuromonitoring?

Neuromonitoring: historyNeuromonitoring: history

•Laryngeal palpation with stimulation of RLN: feel for laryngeal Laryngeal palpation with stimulation of RLN: feel for laryngeal

twitch twitch •Riddell published in 1970, studies over 1946-1960 Riddell published in 1970, studies over 1946-1960

•Palpation of posterior crico-arytenoid muscle, with stimulation of Palpation of posterior crico-arytenoid muscle, with stimulation of

0.5-2.0mA 0.5-2.0mA •Galivan 1986Galivan 1986

Evolution of RLN Evolution of RLN MonitoringMonitoring

• Intra-operative Intra-operative invasiveinvasive techniques techniques

• Non-invasiveNon-invasive surface electrodes surface electrodes

Lamadé W Lamadé W Transtracheal monitoring of the recurrent laryngeal nerve. Prototype Transtracheal monitoring of the recurrent laryngeal nerve. Prototype

of a new tubeof a new tubeIntraoperative monitoring of the recurrent laryngeal nerve. A new Intraoperative monitoring of the recurrent laryngeal nerve. A new

method method Chirurg. 1996 & 1997 Chirurg. 1996 & 1997

NIM monitorNIM monitor

Stimulator Stimulator probeprobe

ETT electrodesETT electrodes

ETTETT

RLN identified both RLN identified both visuallyvisually and and electricallyelectrically

Bergenfelz A Bergenfelz A Langenbecks Arch Surg 2008 Langenbecks Arch Surg 2008 1/10 1/10

11.311.3%%

Chiang FY Chiang FY Surgery 2005Surgery 2005 3/40 3/40

7.57.5%%

Lo CY Lo CY Arch Surg 2000Arch Surg 2000 5/335/33 1515%%

Patlow CA Patlow CA Ann Surg 1986Ann Surg 1986 1/10 1/10 1010%%

Caldarelli DCaldarelli D Otolaryngol Clin North Am 1980 Otolaryngol Clin North Am 1980 1/10 1/10

1010%%

IntraoperativeIntraoperative evidenceevidence of RLN injuryof RLN injury

AuthorAuthor ReferenceReferenceEvidence RLN injuryEvidence RLN injury

NN %%

Scandinavian Quality Register Thyroid Surgery Scandinavian Quality Register Thyroid Surgery

Intraoperative RLN injury causesIntraoperative RLN injury causes

• Section (mistake in surgical technique)Section (mistake in surgical technique)• Ligature (without transection)Ligature (without transection)• Mistake in hemostasis and dissection maneuversMistake in hemostasis and dissection maneuvers• Stretch/tractionStretch/traction

– Excessive traction during the medial traction of the thyroid lobeExcessive traction during the medial traction of the thyroid lobe– Excessive aspiration near to the nerve (suction)Excessive aspiration near to the nerve (suction)

• Compression/contusion/pressureCompression/contusion/pressure• Thermal/electrical injuryThermal/electrical injury

– Diffusion by haemostatic devices Diffusion by haemostatic devices

• IschemiaIschemia– Ligation of the inferior pole vessels before identifying RLNLigation of the inferior pole vessels before identifying RLN– Excessive dissection of the nerve with ischemiaExcessive dissection of the nerve with ischemia

Types of nerve injuryTypes of nerve injury

– neuropraxia: simple contusion of a nerve• treated by simple observation• return to normal function over weeks to months

– axonotmesis: more significant disruption followed by degeneration• healing takes a prolonged time

– neurotmesis: complete division of a nerve• requires surgical repair

anatomical nerve lesions are only

exceptional reasons for postop

VC palsyDralle H. WJS 2008Dralle H. WJS 2008Bergenfelz A . Bergenfelz A . Langenbecks Arch Surg 2008 Langenbecks Arch Surg 2008

Chiang FY . Surgery 2005Chiang FY . Surgery 2005Lo CY . Arch Surg 2000Lo CY . Arch Surg 2000Patlow CA . Ann Surg 1986Patlow CA . Ann Surg 1986Caldarelli D. Otolaryngol Clin North Am 1980Caldarelli D. Otolaryngol Clin North Am 1980

• NoNo routine post-operative laryngoscopy routine post-operative laryngoscopy 0.3% RLNP0.3% RLNP

• Routine postoperative laryngeal exams Routine postoperative laryngeal exams 7% RLNP7% RLNP

AUDITAUDITTrue incidence of RLN injuryTrue incidence of RLN injury

Graves’ diseaseGraves’ disease 1.401.40 <0.43<0.43 1.951.95 <0.37<0.37

Recurrent goiterRecurrent goiter 4.064.06 <0.0001<0.0001 89.9689.96 <0.0001<0.0001

ThyroiditisThyroiditis 0.040.04 <0.83<0.83 0.020.02 <0.92<0.92

Uninodular goiter*Uninodular goiter* 1.271.27 <0.41<0.41 1.431.43 <0.51<0.51

IONMIONM 0.580.58 <0.008<0.008 0.300.30 <0.004<0.004

ParameterParameter

Transient RLN palsyTransient RLN palsy Permanent RLN palsyPermanent RLN palsy

Odds ratioOdds ratio P valueP value Odds ratioOdds ratio P valueP value

Am J Surg 2002Am J Surg 2002

1.1. Evidence from the Literature (?) Evidence from the Literature (?)

19

2.2. Evidence from the Literature (?) Evidence from the Literature (?)

Dralle H, WJS 2008Dralle H, WJS 2008

• Adds Adds earlyearly and and definitedefinite localization of RLN localization of RLN – To prevent visual misidentificationTo prevent visual misidentification– To avoid excessive tractionTo avoid excessive traction– To identify extralaryngeal branches, anatomical To identify extralaryngeal branches, anatomical

variation, distored RLN, non-RLNvariation, distored RLN, non-RLN

• AddsAdds confirmation of RLNconfirmation of RLN

• Adds dissection of RLNAdds dissection of RLN

Reasons for RLN protection with Reasons for RLN protection with IONMIONM

Nerve Identification2mA

Nerve Confirmation1-0.5mA

Nerve Confirmation0.5mA

The answer is very simple:

based on anatomical nerve assessment alone

1. the frequency of postop VC dysfunction is more common than

expected

2. because anatomical nerve lesions are only exceptional reasons for postop VC

palsy

Why neuromonitoring?Why neuromonitoring?

Which is the fundamental difference between visual identification and

RLN monitoring?

RLN monitoring can change strategy

Strategy changes in bilateral goiter

36 LOS at first side

16 unchanged strategy↓

9 (56%) unilateral palsy 3 (19%) bilateral palsy

20 changed strategy↓

20 (100%) unilateral palsy 0 bilateral palsy

When LOS is real:How to treat RLN injury intraoperatively?

Intraop steroids*(n=143)

No intraop steroids(n=152)

NAR

Vocal corde palsytemporary

permanent

Recovery (days)

194 173

11 12 1 1

28.6 (10-36) 37.4 (14-61)**

MEDICO-LEGAL ISSUESMEDICO-LEGAL ISSUES

• Reduction of major injury to patientReduction of major injury to patient– Bilateral RLN palsyBilateral RLN palsy

• Recorded nerve signalRecorded nerve signal

• Early differentiation between RLN related

and unrelated voice changes

• New standard of care (?) New standard of care (?)

US thyroid surgery monitoredUS thyroid surgery monitored

IONM procedures in AsiaIONM procedures in AsiaChiang FY, 2011Chiang FY, 2011

DanmarkDanmark 77% 77% 20072007 Godballe C, ETA Meeting, Lisbona,Godballe C, ETA Meeting, Lisbona,

PolandPoland 5%5% 20102010 Barcinsky M, Barcinsky M, Polish Endocrine SurgeonsPolish Endocrine Surgeons

Germany Germany 90% 90% 20112011 Dralle HDralle H, Harvard Meeting, Boston, Harvard Meeting, Boston

FranceFrance #6200 #6200 20082008 Carnaille B, IONM study groupCarnaille B, IONM study group

France #10000 France #10000 20102010 Carnaille B, IONM study groupCarnaille B, IONM study group

SpainSpain ##613613 20092009 Manuel Poveda, Madrid 2010Manuel Poveda, Madrid 2010

SpainSpain #1956#1956 Jan-aprilJan-april 2011 2011 Manuel Poveda, Madrid 2011Manuel Poveda, Madrid 2011

IONM PREVALENCE IN IONM PREVALENCE IN EUROPEEUROPE

PREVALENCE IN PREVALENCE IN ITALYITALYsource Medtronic Italysource Medtronic Italy

2.6.1. Darstellung des Nervus laryngeus recurrensFunktionsstörungen des Nervus laryngeus recurrens sind mit Stimmstörungen, Schluckstörungen und Beeinträchtigungen der Atmung verbunden. Bei bilateraler Rekurrensparese ist häufig eine Tracheotomie erforderlich. Das Risiko, den N. laryngeus recurrens zu verletzen, wird durch das Ausmaß der Resektion und die individuelle Lagevariante des Nerven bestimmt. Die schonende, das heißt nicht-skelettierende, nervendurchblutungserhaltende präparative Darstellung des N. laryngeus recurrens mindert das Schädigungsrisiko und sollte grundsätzlich sowohl bei Primäreingriffen als auch bei Rezidiveingriffen durchgeführt werden (6, 18). Der visualisierte anatomische Nervenverlauf sollte vor und nach Resektion dokumentiert werden. Ausnahmsweise kann auf die Darstellung verzichtet werden, wenn sich die Resektionsebene in sicherem Abstand ventral der lateralen Grenzlamelle zum Nervenverlauf befindet (46). Die Nichtdarstellung des Nervus laryngeus recurrens soll begründend dokumentiert werden.Das intraoperative Neuromonitoring ersetzt nicht den Goldstandard der visuellen Nervendarstellung, sondern ist nur in Ergänzung zu dieser einsetzbar. Das Verfahren kann die Identität des Nervus laryngeus recurrens sicher bestätigen und seine Funktionsfähigkeit bei ungestörtem Überleitungssignal sehr wahrscheinlich machen, wobei zur Erfassung des gesamten Nervenverlaufes die Stimulation über den Nervus vagus vor und nach Resektion erforderlich ist (10, 17, 28, 48, 50). Die sicherste Methode zur Differenzierung zwischen Artefakten und Aktionspotenzialen ist die Ableitung von Elektromyogrammen. Eine signifikante Senkung des Rekurrenspareserisikos durch Einsatz des Neuromonitoring ist bislang nur bei Rezidiveingriffen gesichert (9, 28).

http://www.dgch.de

German Association of Endocrine SurgeonsLangenbecks Arch Surg 2011;396(5): 639-649German Association of Endocrine SurgeonsLangenbecks Arch Surg 2011;396(5): 639-649

Polish Journal of Surgery (transl).Polish Journal of Surgery (transl).

Guideline Statement of the Polish Study Group for Nerve Monitoring of Guideline Statement of the Polish Study Group for Nerve Monitoring of the Polish Club of the Endocrine Surgeonsthe Polish Club of the Endocrine Surgeons

Members of the Study Group for Nerve Monitoring of the Polish Club ofMembers of the Study Group for Nerve Monitoring of the Polish Club ofEndocrine Surgery during the conference on 16th of April 2011 in KrakowEndocrine Surgery during the conference on 16th of April 2011 in Krakowopine that opine that centers of thyroid surgery in Poland should be equipped withcenters of thyroid surgery in Poland should be equipped with

nerve integrity monitoring systemsnerve integrity monitoring systems..

Following the analysis of the publishedFollowing the analysis of the publisheddata and based on our own experience the need to introduce routine trainingdata and based on our own experience the need to introduce routine trainingcourses of courses of standardized technique standardized technique of electrophysiological monitoring of theof electrophysiological monitoring of the

recurrent nerves and employment of this technique in recurrent nerves and employment of this technique in selected thyroidselected thyroidoperations operations was recognized". was recognized".

NeuromonitoringNeuromonitoring for residents for residents in surgical trainingin surgical training

• Incorporating new technology

• Teaching aid

• Elucidate errors

• Less-experienced surgeons

– IONM decrease RLN paralysis (Dralle H,

2004)

LIMITATIONS OF LIMITATIONS OF IONMIONM

1.1. RLN palsy still occurRLN palsy still occur

2.2. need for standardized and well-trained use to avoid pitfallsneed for standardized and well-trained use to avoid pitfalls

3.3. knowledge of most-common pitfalls knowledge of most-common pitfalls

4.4. ability to use troubleshooting algorithmsability to use troubleshooting algorithms

5.5. IONM does not replace clinical judgmentIONM does not replace clinical judgment

6.6. relatively low positive predictive valuerelatively low positive predictive value

7.7. cost-effectiveness is still not evaluatedcost-effectiveness is still not evaluated

8.8. need for further research focused on neurophysiology of the RLNsneed for further research focused on neurophysiology of the RLNs

9.9. IONM of the external branch of the superior laryngeal nerveIONM of the external branch of the superior laryngeal nerve

10.10.thyroidectomy in local anesthesiathyroidectomy in local anesthesia

ConclusionConclusionss

• RLN monitoring improves

– Nerve ID (Randolph GW, 2002)

– Clarification of RLN anatomy (Delbridge 2002)

– Nerve dissection (Chan WF 2006)

– Reoperations with pre-existing RLN morbidity (Gorentzy P, 2008)

• Intraoperative assessment of RLN function (non postoperative)

– Intraoperative prediction of post-operative function (prognosis) (Timmermann W,

2004)

– Prevention of bilateral RLN injury: “one-stage thyroidectomy” (Randolph GW, 2002)

– Elucidate where and how the RLN was injured (intraoperative evidence) (Chan WF

2006)

– Early differentiation between RLN related and unrelated voice changes (Dralle H

2004)

WhyWhy should RLN be monitored in any should RLN be monitored in any bilateral case ?bilateral case ?

IMPLICATIONS

CLINICAL PRACTICECLINICAL PRACTICE RESEARCHRESEARCH EDUCATION EDUCATION MEDICO-LEGALMEDICO-LEGAL

IONM technology in thyroid surgery IONM technology in thyroid surgery (IONM: intraoperative neuromonitoring)(IONM: intraoperative neuromonitoring)

Surgeons should not overstate Surgeons should not overstate

benefits of neuromonitoring to benefits of neuromonitoring to

patientspatients

Modern SurgeryModern Surgery

•ERADICATION OF DISEASEERADICATION OF DISEASE

•SAFETY OF PROCEDURESAFETY OF PROCEDURE

•DOCUMENTATIONDOCUMENTATION