Author

Stephen J. Birchard DVM, MS, Diplomate ACVS

Thursday, November 21, 2013

Dehiscence of the Intestinal Incision: Why does it happen and how can we prevent it?

Dehiscence of an enterotomy of the jejunum in a dog
You have just completed an intestinal anastomosis. The bowel looks healthy, there was minimal contamination, and the remainder of the abdomen looks good. The omentum has been tucked into place around the bowel and you close the abdominal incision.

Now begins the period of postoperative anxiety (for you, not the patient). For the next 3 days every time the dog vomits, spikes a fever, doesn’t eat, or seems painful in the abdomen, your “worry-meter” will go off the charts.  You will ask yourself many questions: did you remove all of the diseased bowel, are your sutures holding, was there another perforation or foreign body that you missed, or is the animal just not healing properly? The source of the anxiety of course is that postoperative intestinal leakage is a devastating complication. One study found a dehiscence incidence of 16% of enterotomies and anastomoses in dogs, with a mortality rate of 74%.1 Dogs with foreign bodies and trauma appeared to be at higher risk for dehiscence in this study. Clinical evidence of peritonitis appeared at about 3 days postoperatively.

Intestinal wound breakdown can also occur after full thickness biopsy.  Eight of 66 dogs died or were euthanized due to dehiscence of intestinal biopsy sites in a British clinical study.2 No specific factors predisposing dogs to biopsy dehiscence were identified in the study.

Pathophysiology

Why do intestinal incisions sometimes breakdown and can we do anything to prevent it? In a study of dogs having intestinal surgery, high risk for dehiscence was found if a dog had 2 of the 3 following clinical factors: pre-existing peritonitis, foreign body, or a serum albumin of less than 2.5g/dl.3 This is valuable information and serves to heighten the surgeon’s awareness of postoperative septic peritonitis in selected dogs or cats that fit these criteria. Monitoring of pre- and postoperative serum albumin levels after gastrointestinal surgery, in addition to routine patient parameters (temperature, abdominal pain, vomiting, etc.), appears warranted.

In addition to these well-documented dehiscence factors, clinical experience tells us that dogs with metastatic intestinal neoplasia are also at higher risk for incisional breakdown. Dogs with abdominal carcinomatosis seem particularly prone to poor healing of their incisions.

Prevention

Prevention of peritonitis secondary to intraoperative contamination is by following good surgical technique: packing off the intestine with abdominal sponges, keeping tissues moist, atraumatic technique, use proper suture materials and patterns, and short surgical time. Abdominal lavage is not indicated in dogs that do not have generalized peritonitis. Local lavage of the affected intestinal segment is fine but do not allow fluid to enter the peritoneal cavity. Abdominal lavage fluid has been found to potentiate peritonitis by distributing bacteria and inhibiting phagocytosis by macophages and neutrophils. Abdominal lavage however is indicated in animals with existing peritonitis.

Prophylactic antibiotics, i.e. those given prior to and during surgery but not postoperatively, are also recommended for gastrointestinal surgery in dogs and cats. However, unless the animal already has septic peritonitis, antibiotics are not continued after surgery because continued administration has no benefit and may actually be detrimental. Unnecessary antibiotic administration leads to development of resistant bacterial species and may mask the early signs of peritonitis making it more difficult to diagnose.
Closed suction drain (Jackson-Pratt) used for abdominal drainage in peritonitis
Clinical signs of postoperative septic peritonitis are: abdominal pain, vomiting, anorexia, fever, neutrophila and left shift on complete blood count, and peritoneal fluid that contains bacteria. Treatment is re-operation, resection of the involved intestinal segment (do not try to just re-suture it), abdominal lavage with copious amounts of sterile saline, and placement of a closed suction drain (e.g. Jackson Pratt). Postoperative care includes fluids and colloids, antibiotics, nutritional support, and careful monitoring.

References

1. Allen DA, Smeak DD, Schertel ER. Prevalence of small intestinal dehiscence and associated clinical factors: a retrospective study of 121 dogs. J Am Anim Hosp Assoc 1992;28:70-76.
2. C J Shales, J Warren, D M Anderson, S J Baines, R A S White. Complications following full-thickness small intestinal biopsy in 66 dogs: a retrospective study. Journal of Small Animal Practice 08/2005; 46(7):317-21.
 3. Ralphs SC, Jessen CR, Lipowitz AJ. Risk factors for leakage following intestinal anastomosis in dogs and cats: 115 cases (1991-2000). J Am Vet Med Assoc 2003;223:73-77