1.COMPLICATIONS When Things Go WrongDane Tatarniuk, DVM

2. DISCUSSION POINTS Gastrointestinal Orthopedic Adhesions Casts Incisional Infections Implant Infection Incisional Dehiscence Incisional Hernia Rectal Tears Ileus 3. The one who does not operate does not have complications. 4. ADHESIONS Prevalence of clinical adhesions: Range 6% to 26% after small intestinal surgery More common in foals (up to 6 months) than weanlings and yearlings Foals < 30 days are at greater risk than foals >30 days Anastomosis & enterotomy sites Prolonged post-operative ileus Repeat laparotomy Peritonitis Abdominal Abscess Chronic intermittent colic or acute obstructive clinical signs Most complications from adhesions occur within the first 60 days 5. ADHESIONS Pathophysiology: Theory: Detrimental process caused by inflammation andischemia, causing a depression in fibrinolysis. Peritoneal injury creates inflammation & ischemia Inflammation: Intestinal distension, abrasion of serosa, surgical manipulation of intestine,infection, bacterial contamination, foreign material (suture, glove powder). Ischemia: Strangulating lesion, vascular compromise, intestinal distension, tight sutureplacement. Creates an imbalance between fibrin deposition and fibrinolysis 6. ADHESIONS All comes back to thecoagulationcascade Peritoneal injurystimulates intrinsicand extrinsic cascade Principal modulator ofadhesion formation isthe fibrinolysissystem, which worksthrough the enzymeplasmin Key regulators offibrinolysis are tissueplasminogen activatorand urokinaseplasminogen activator 7. ADHESIONS Normally Lysis of fibrin and fibrinous adhesions occur in 48 72 hours after peritonealinjury Mediated through plasmin-mediated fibrinolysis Normal tissue restoration results However If excessive ischemia or inflammation occur, a depression in peritonealfibrinolysis activity occurs Causes fibrin accumulations to become infiltrated with fibroblasts andcapillaries End result: Permanent fibrous adhesions, formed 7 to 14 days after surgery. Adhesions can obstruct bowel lumen, incarcerate smallintestine, distort or kink the mesentery or intestine. End result is recurrent colic! 8. ADHESIONS Prevention Gentle tissue healing Remove damaged tissue Meticulous hemostasis Minimize surgical time Frequent, copious lavage to keep bowel moist Medication Broad spectrum antibiotics Non-steroidal anti-inflammatories Dimethyl sulfoxide 9. ADHESIONS Abdominal Lavage At surgery, prior to closure Post-operatively, passive or closed suction drains Removes blood, fibrin & inflammatory mediators Mechanical separation of bowel Clinical research present that supports abdominal lavage Serosa abrasions and peritoneal drains placed in 12 horses at surgery 6 received post-op abdominal lavage for 34 hours after surgery; 6 did not(controls) Necropsied at 2 weeks post-op Severe adhesions in all 6 controls, none present in the lavage group No adverse reactions from lavage noted in treated group 10. ADHESIONS 1% Sodium Carboxymethocellulose Belly Jelly Provides a mechanical barrier between serosal andperitoneal surfaces Helps reduce trauma by acting as a lubricant 0.4% Sodium Hyaluronate also used Bioresorbable Hyaluronate-Carboxymethylcellulose Membrane Membranes that are applied to anastomosis sitespost R&A Act as a temporary protective barrier 11. ADHESIONS Carolina Rinse Used in human medicine for organ transplants Decreases reperfusion injury Decreases migrations of neutrophils into serosa Decreases fibroblast proliferation Applied topically and intraluminal Compounded, not commercial Systemic Heparin Cofactor of Anti-thrombin III Decreases production of thrombin Thrombin responsible for convertingfibrinogen to fibrin Also stimulates plasminogen activator activity 12. ADHESIONS Omentectomy Anastomotic Techniques Controversial Small intestinal R&A sites are Studies showing thathigh risk for adhesionprophylactic omentectomydevelopmentreduces adhesion formation Goals: However, omentum mayprovide blood supply to 1) Maintain proper tissue alignmentischemic intestine2) Promote optimal intestinal Facilitates healing withinhealingthe peritoneum3) Complete mucosal coverage Surgeon preference4) Minimal suture exposure 13. ADHESIONS Second Laparotomy Based on history and diagnostic findings Primary goal is to reduce adhesions Catch 22 Removal of adhesions incites serosal inflammation Predisposes for further (recurrent) adhesion formation If adhesion mass is too large or cannot be exteriorized to the incision Consider gastro-intestinal bypass surgery Horses requiring a second look laparotomy due to adhesions have a 20% prognosis for survival 14. ADHESIONS Elective Laparoscopy Generally performed 7 to 10 days post-operative Time period when adhesions are fibrinous and easy to break down Visualization of adhesions is variable Dependent on area of scarring and position of adhesions Position of horse, standing or recumbent Acute colic: Sensitivity of 82%, Specificity of 66% Chronic colic: Sensitivity of 63%, Specificity of 33% 15. Every operation in surgery is an experiment in bacteriology. 16. INCISIONAL INFECTION Increases risk of incision dehiscence, abdominal herniation, eventration Retrospective reports show prevalence of infection between 7.4% and 37% Incidence after 2 or more celiotomies performed within 6 months time may beas high as 87.5% Predisposing factors: Repeat celiotomy Increased duration of surgery Use of near-far-far-near pattern Chromic gut Leukopenia Edema Post-operative pain Weight (>300kg) 1+ year vs. < 12months 17. INCISIONAL INFECTION Early indications: Fever of unknown origin Excessive tenderness with palpation Warm edema formation Systemic antibiotics usually delay drainage See drainage around 3 days post-operatively Can be delayed up to 14 days 18. INCISIONAL INFECTION Common sense preventative measures Decrease surgical time Proper aseptic preparation of the abdomen Meticulous draping during enterotomy Minimize trauma to incision during draping Other measures Decreased incidence when antibiotics are applied topically to surgical wound at time of closure (Mair et al.) Decreased incidence when temporary drape is applied over incision during recovery (Ducharme et al.) Can fall off easily Decreased incidence when an abdominal bandage was used post-operatively vs. no bandage (Smith et al.) 19. INCISIONAL INFECTION Minimal research on suture type/pattern and incidence of incisions Guidelines: Perform closure with minimally reactive suture Braided, non-absorbable suture may cause suture sinus formation Avoid overtly large bites creates excessive tension & predisposes to ischemia Optimal tissue bite for adult horses is 15mm from linea alba edge Management: Culture & sensitivity of incision is indicated Establish drainage May require removal of skin or subcutaneous sutures / staples Local & systemic antibiotics indicated if horse is febrile, or excessiveedema, cellulitis present 20. INCISIONAL INFECTION Management continued Flushing of incision is not encouraged can propagate infection down incision line Belly bandage important to sustain abdominal support (risk of dehiscence) 21. INCISIONAL DEHISCENCE Rare but potentially devastating complication Prevalence after ventral midline celiotomy less than 1% Factors: Interrupted suture patterns in linea alba less likely to dehisce However, continuous patterns have been showing to be stronger Increased surgical time Incisional trauma during surgery Recovery Rolling or abdominal impact during recovery Creates a sudden increase in abdominal pressure Post-operative debility Obesity, age (older), incisional infection 22. INCISIONAL DEHISCENCE Dehiscence usual occurs 3 8 days post op. Often preceded by incisional drainage Brown serous-anguinous Abdominal bandages do not prevent dehiscence But can prevent eventration of bowel If used, incision needs to be checkedfrequently Failure of body wall can progressrapidly 23. INCISIONAL DEHISCENCE Management Apply belly bandage, if not already in place Anesthetize horse Examine, decontaminate, and potentially repair the incision. Minimal contamination Early detection and minimal bowel ischemia Remove superficial contamination with lavage Marked contamination Lavage at surgery & place indwelling abdominal catheter for standing lavage 24. INCISIONAL DEHISCENCE Closure of abdomennecessary Surgical debridement ofincision Remove necrotic, infected tissue Closure Full thickness vertical mattresssutures Stainless steel wire (22 gauge) Stents 2-3cm apart from eachother 5cm apart from wound edge Incision brought intoapposition Skin left open for drainage 25. INCISIONAL HERNIA Most important risk factor for incisional herniation is incisionalinfection Relative risk factor of 17.8 Ventral midline hernia incidence post-op between 1% & 10% Hernias are apparent within 3-4 months post-operatively Contributing factors: Increase intra-abdominal pressure from pain Entrapped fat between hernia edges Poor suture placement, suture selection, soft tissue handling 93% of sutures fail at the knot Suture loops usually fail before fascial disruption occurs 26. INCISIONAL HERNIA Clinically, hernias are usually noted cranially more than caudally Linea alba is thickest near umbilicus & thins cranially Many can be managed conservatively Skin incision non-healed, Consider sterile abdominal compression bandages Abdominal bandaging for 1-2 months, while treating any underlying infection, helps reduce hernia size substantially 27. INCISIONAL HERNIA If hernia fails to heal, or enlarges after turn-outsurgery Hernia repair a cosmetic indication Large hernias can be repaired with synthetic mesh Knit polypropylene mesh Strong, elastic, inert, resists infection Tissue grows through mesh and incorporates into herniorrhaphy Need to make sure all infection is cleared prior to implanting mesh May require removal of infected suture material from sinus tracts first 28. INCISIONAL HERNIA Technique 180 degree skin incision at margin of herniaring Follow through with fascia and fibrous tissue Fascia is removed using retroperitonealdissection Peritoneum is left intact Can be difficult if adhesion between fascia and peritoneum intact Or, if very thin fascia present Inadvertent penetration of peritoneum complication Some advocate mesh implant in subcutaneous space rather than retroperitoneal space 29. INCISIONAL HERNIA Technique continued Thin layer of mesh cut to sizeand incorporated Closure with horizontalmattress sutures, #2polypropylene suture Sutures are pre-placed make sure mesh lies flat andsnug then tighten/tie sutures Reattach flap Belly bandage to preventedema/seroma formation veryimportant 30. INCISIONAL HERNIA Novel technique Laparoscopic mesh repair reported Removal of retroperitoneal fat Expose internal rectus shealth Introduce prosthetic mesh and attach using trans-facial sutures Examined several months later no indication of adhesion formation to mesh 31. Do not congratulate yourself for saving a patient from a trouble inflicted by you 32. RECTAL TEARS Occur from diagnostic palpation of the rectum Usually veterinarian induced, sometime caretaker/owner Malpractice Copious lubrication & adequate restraint Causes Most occur from rupture of rectal wall as rectum contracts around arm Not commonly from penetration with finger tips Less common causes Enemas Meconium extraction in foals Dystocia Chronic impactions at strictures Rectal thrombosis Sand impactions +/- Spontaneous tears 33. RECTAL TEARS Idiopathic tears Tend to be transverse One report of 5 horses revealed 4 presented with colic 1 occurred during lameness exam Suspect literature Idiopathic tears are usually presented as colic of variable duration No reason to suspect rectal tear referral often delayed 34. RECTAL TEARS Avoidance Dont force against a peristaltic wave Special care in Arabians, smaller horses, horses with previous tears, fractioushorses Legal Recommendations Assess severity immediately (determine grade) Referral Inform owner Make no statements that imply admission of guilt or assume responsibility ofpayment 35. RECTAL TEARS Classification: Four Grades Grades are important to dictate treatmentplan Grade 1 Mucosa, Submucosa Grade 11 Muscular layer torn, only Mucosa, Submucosa intact M, SM prolapse into defect Create area for fecal material toaccumulate More rare (3 of 85 in retrospectivereview) 36. RECTAL TEARS Grade III IIIa Involve all layers except serosa IIIb Involve all layers except mesorectum, retroperitoneal tissue Grade 3b tears can pack with feces and create plane of dissection cranially anddorsally Grade IV Involves all layers Most serious fecal contamination of peritoneal cavity 37. RECTAL TEARS Indicators: Sudden release of pressure Direct palpation of abdominal organs Blood on rectal sleeve Within 2 hours after Grade IV tear, horse will show signs ofperitonitis, endotoxic shock, low-grade colic, depression. Feces may be stained hemorrhagic Defecation accompanied by straining Most involve dorsal rectum, are 15 to 55cm from anus, and areparallel to the longitudinal axis. 38. RECTAL TEARS Stop straining Sedation Epidural Prior to examination of tear Eliminates straining and rectal contractions Buscopan Lidocaine enema Inspect tear using tube speculum or endoscope Rectal folds can obscure visualization of tear Alternatively, palpate digitally with gloved hand 39. RECTAL TEARS Non-surgical management Reduce activity of rectum Gentle removal of feces from rectum Treatment of septic shock, peritonitis Administration of epidural Packing of rectum Grade 1, 2 tears antibiotics, laxatives, packing of rectum Rectal packing Prevent conversion of grade 3 to 4 Protect tear from fecal contamination during healing period 40. RECTAL TEARS Material 3 inch stockinet filled with moistened rolled cotton Soaked in povidone-iodine Outside lubricated with surgical gel Apply packing 10cm proximal to tear Close anus with towel clamps or purse-string Grade 1: Generally heal in 7 10 days 41. RECTAL TEARS Grade 2 Can over-sew diverticulum via laparotomy Grade 3, 4 Require some form of surgical management Standing repair per anus Expandable speculum Difficult to maneuver, blind approach Can be combined with diverting procedure if concern of integrity of repair Best in fresh, clean tears close to anus Can incise anal sphincter to improve access Simple & inexpensive 42. RECTAL TEARS Technique Epidural, evacuate rectum, clean tear with moist4x4s, gentle gravity lavage Suture: 5 Dacron, 6 to 8cm, half cutting or trocarpoint needle, needle halfway on suture thread Simple interrupted or cruciate Continuous = stricture, dehiscence May cause lumen reduction, edges turn into lumen Suture ends kept long to facilitate removal Rectal performed at 24, 48 hours Suture that feels slack from loosening, decreasededema is removed & replaced Sutures removed in 12 to 14 days Learning curve 43. RECTAL TEARS Deschamps needle Similar to indirect hand sutured technique Needle attached to extended long arm with handle Both left, right configurations One hand works the instrument, the other hand is placed rectally and guides the tissue onto the needle 44. RECTAL TEARS Temporary Indwelling Rectal Liner Horse anesthetized, dorsal recumbancy Prolapse ring with rectal sleeve attached Pass well-lubricated ring through anus Surgeon guides ring proximal to tear Circumferential suture (#3 catgut) placed around small colon, followed by equidistantretention sutures & Lembert apposition of serosa Pelvic flexure enterotomy Circumferential suture cuts through rectal wall in 9 12 days Allows passage of ring/liner in feces Four retention sutures keep ring in normal alignment, so that small colon does nottwist or obstruct lumen Failures caused by tearing of sleeve, retraction of sleeve, formation of recto-peritoneal fistula 45. RECTAL TEARS Diverting Loop Colostomy Gravity prevents passage of feces into distal small colon Can be performed standing incision into flank Made 1 meter from rectum, in small colon Fold small colon and suture together using absorbable material, lembert Sero-muscular layer of colon sutured to abdominal muscles, fascia Stoma made along the anti-mesenteric side of colon (size of colon lumen) Sutured to skin, simple interrupted, 2-0 nylon or prolene 46. RECTAL TEARS Colostomy Reversal Lateral recumbancy Resect the stoma Perform colonic anastomosis Incision infection very high Often place penrose drains, left in place, for ~3 days Complications of Correcting a Complication Dehiscence Abscessation Peri-stomal herniation Prolapse Spontaneous closure Rupture of colostomy Anastomotic impaction / dehiscence 47. RECTAL TEARS Complications of Surgical Overall Prognosis: Management: Conservative 82% Peritonitis Surgical 55% Rectal stricture Pelvic Abscesses Future techniques: Laparoscopic repair 48. Nothing spoils good results as much as follow up. 49. ILEUS Def: A disruption of the normal propulsive motility of the GI tract Risk factors: Prolonged surgical/anesthetic time Small intestinal lesions (particularly strangulating) Elevated PCV Indicators Post operative colic Elevated heart rate Anorexia Depression Prevalence: Occurs in 10 to 20% of colic surgeries 50. ILEUS Recognition: Pass nasogastric tube and reflux horse After nasogastric intubation, ultrasound/rectal can be performed Indicator of severity Ultrasound: Small intestinal distension with/without sedimentation Minimal to absent motility 51. ILEUS Gastric decompression, every 2-4 hours, isimportant part of management Also helps provide a benchmark to evaluate response totherapy Nasogastric tube may be left indwelling or re-placed each time Left indwelling can delay gastricoutflow, perpetuating/prolonging problem Re-placement each time may cause more irritation anddistress to horse Pharyngeal trauma Esophageal rupture 52. ILEUS Fluid therapy: Adjust IV fluid rate to compensate for gastric refluxloss Maintenance fluid rate (2 mL/kg/h) + Quantity of gastric reflux (L/h) = totalhourly crystalloid fluid requirement Anticipate hypocalcaemia & hypokalemia Calcium smooth muscle in gastro-intestinal tract / vessels requireextracellular Ca for motility Consider parenteral nutrition in horses with long-standing ileus 53. ILEUS Pro-kinetic therapy Used in refractory cases Lidocaine most commonly used Others: Erythromycin Metoclopramide Neostigmine 54. ILEUS Lidocaine Affects contractility in the proximal duodenum only Well tolerated In-vivo, has been shown to decrease jejunal distension and peritoneal fluidaccumulation Improved time for fecal passage and shorter hospitalization stays In normal horses, have not been able to demonstrate pro-motility effects Current theory is that lidocaine acts as a pain modulator, thereby allowingmotility Toxicity: Tremors, muscle fasciculations, somnolence, collapse Stop therapy until signs resolve Effective for about 36 hours post-initiation 55. ILEUS Erythromycin Stimulates motilin receptors Affects contractility in the pyloric antrum and middle jejunum Where motilin receptors are most concentrated Macrolide antibiotic Very effective in improving gastric emptying time Complication : can create colitis / diarrhea 56. ILEUS Metoclopramide Affects contractility in pyloric antrum, proximal duodenum, and middle jejunum Administered intermittently or continuously Dopamine antagonist - Increases myo-mechanical activity Toxicity when metoclopramide crosses the BBB into CNS Excitement Restlessness 57. ILEUS Failure to respond to therapy results from secondarydamage due to distension Distension causes injury to the muscle structure and myentericneurological control as a result of ischemia On histology Hemorrhage, edema, neutrophillic infiltrate Have not been able to demonstrate improved survivalrates with pro-kinetic use Comes down to patience and crossed fingers 58. The less its indicated; the more complications. 59. CAST COMPLICATIONS Hard to avoid, if you place enoughcasts Change the cast if: Diminishing comfort Focal heat Odor Discharge Develop from overly tightapplication Dermal pressure necrosis Overly loose application Swelling decreases Muscle atrophy Compression of cast padding 60. CAST COMPLICATIONS Too short a half limb cast Severe tendon injury limb is partially flexed Linear pressure on unprotected tendons Proximal dorsal cannon bone sore Can apply a heel wedge to offset pressure applied by cast Still recommended to change cast within 7 14 days Absolutely need to keep cast on Consider trans-fixation pins Will limit motion within cast possible decrease rub sores Complications include: Thermal injury & ring sequestra Pin breakage 61. CAST COMPLICATIONS Broken cast Ideally should be replaced However, can patch cast if the hinge at the break is minor Most casts break over point of a joint Apply 90% of cast material in longitudinal direction over compression side ie. dorsal fetlock Applying more cast material circumferentially usually re-fails 62. CAST COMPLICATIONS Cast Removal Oscillating saw inadvertent damage to flexor tendonson palmer aspect Cutting over infection or implant Seed infection - contamination of deep tissues Foals Post-coaptation laxity of tendons Pro vs. Con Decide whether stabilization more important thanpotential laxity Helps to gradually decrease coaptation with progressively lighter bandages, application of splints Heel extension glue on shoes 63. The source of most complications is in the operating room. 64. IMPLANT INFECTIONS The most significant complication inorthopedic surgery Contributes to the cost, cosmetic andfunctional outcome of a case Increases cost 5 to 10 fold Infection can lead to instability of internal fixation Possible outcomes include mechanical failure or delayed/non-union healing The first step in treating implant infections isrecognizing that sepsis is present The earlier the realization = the better theintervention 65. IMPLANT INFECTIONS Indications: Fever, otherwise non-explainable Decrease in comfort Failure of swelling to decrease post-operatively Return or development of swelling post-operatively Drainage Failure of incision to heal Blood-work Plasma fibrinogen best indicator Leukocytosis not conclusive; can be normal with infection present 66. IMPLANT INFECTIONS Radiographs Best indicator of mid to late stage infection Osteolysis Specifically radiolucency at implant cortexinterface Increased soft tissue swelling or dissection of soft tissue planes Periosteal proliferation Not associated with fracture healing Lysis extending into medullary cavity = end stage Ultrasound Exudate adjacent to implants 67. IMPLANT INFECTIONS Goal of therapy Local delivery of high doses of antibiotics to infected tissue / implants Allows high concentration of antibiotic exposure to pathogens Avoidance of systemic side-effects More cost effective using regional techniques Systemic antibiotics alone just doesnt cut it 68. IMPLANT INFECTIONS Follow basic principles of treating infection Drainage: Ultrasound area to visualize exudate Excise tissue intact skin or ventral aspect of incision in a gravitational dependent area Culture: Sensitivity will help provide consistent results Prepare superficial tissues; culture depths ofdraining tract Alternatively, ultrasound guided needle aspirateof exudate 69. IMPLANT INFECTIONS Polymethylmethacrylate Beads Delivers high concentrations of antibiotics Biocompatible with tissue Diffusion of antibiotics from cement well studied Readily available in a sterile, easy to use form Disadvantage non absorbable Disadvantage cant incorporate with heat labile antibiotics Ratio: 1 - 2 grams antibiotic per 10 grams PMMA Gentamicin, amikacin, tobramycin, enrofloxacin, cephalos porins 70. IMPLANT INFECTIONS Plaster of Paris Beads Similar principle as PMMA Main difference is that POP is slowly degraded & absorbed by the body Set up time is slow, therefore best to make POP beads and then sterilize them Can be mixed with a cancellous bone graft 71. IMPLANT INFECTIONS Regional Limb Perfusion Peripheral vessel & isolated limb via tourniquet Concerns: State of tissues close to implant (disrupted vasculature?) May induce vascular damage Enrofloxacin has been shown to induce vasculitis Placement Tourniquet above and below region the best Minimum is exposed vessel distal to proximal tourniquet 72. IMPLANT INFECTIONS Sedation Preventing movement is ideal for adequate tissue penetration of antibiotic Concurrent analgesia can be considered Carbocaine (vs. saline) as volume dilute Local nerve block Catheter Smaller the better Repeated injections require care to preserve vessel integrity 25 to 27 gauge butterfly catheter Volume 1/3rd of antibiotic systemic dose Diluted to 30 to 60ml 73. IMPLANT INFECTIONS Technique Slow injection needle bore small Leave tourniquet in place for 30 to 45 minutes Cover injection site with compression bandage Consider treating injection site with DMSO, Surpass Other indications for regional limb perfusion Wound therapy Joint therapy Pre-operative antimicrobial dosing 74. Complications are a price all veterinarians eventually pay.Experience and increasing skill will decrease many of them butcertainly not all.The most important thing is for the veterinarian to react correctlyto a complication. Acknowledge the mistake (or bad luck)quickly, and take whatever steps you can to correct the problem.Because so many equine cases have the potential forcomplications, recognizing and responding properly to thesecomplications are imperative for successful outcomes. - D.W. Richardson (in: Vet Clinics North America 2008) QUESTIONS?