How to win with intestinal surgery and avoid dehiscence

If you’ve ever felt uneasy after closing an enterotomy, resection and anastomosis, or during any surgery involving the entering the gut, you are not alone. Intestinal surgery can be risky and major complications can have disastrous consequences. In fact, the reported dehiscence rate post intestinal surgery is between 12% and 16%.1-4  There are a variety of factors that play a role in the rate of healing of intestines including the presence of a septic abdomen, failure of a previous surgery, a perforating foreign body, hypotension, hypoalbuminemia, and trauma.1-4

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The upregulation of collagenase during the inflammatory period makes the tissues of the intestinal incision weaker before they become stronger. There are three phases of intestinal wound healing - Lag Phase, Proliferative Phase, Maturation Phase - and they all overlap with the Lag Phase occurring during days 0 to 4. The Lag Phase is associated with inflammation and edema of the intestinal wound. Most of the wound strength in early healing is attributed to sutures. Healing is biomechanically weakest at the end of the Lag phase because of fibrinolysis and collagen deposition and therefore dehiscence commonly occurs between day 3 and 5. After 5 days, the proliferative phase of wound healing predominates (between days 3 and 14) and there is a rapid gain in wound strength. An enterotomy (or enterectomy) should gain close to normal strength between 10 to 17 days following repair. Despite the increase in strength, healing continues with the Maturation phase (10 to 180 days) and this is when collagen is reorganized and remodeled. The goals of any intestinal surgery should be to decrease the length of the intestinal Lag period, maintain a water tight seal, and ultimately improve the surgical outcome. 

Here are some helpful tips:

Salubrious Suture Pattern and Sagacious Suture Selection 

My preference for intestinal closure is a synthetic monofilament of 3-0 or 4-0. There are a variety of other options for suture that can be selected based on the surgeon's preference however, multifilament sutures may increase tissue drag and serve as a scaffold for infection. Natural monofilament (i.e surgical gut) may not provide strength for long enough because its primary mechanism of dissolution is inflammation..  A mid-term or short term absorbable suture may be chosen depending on the surgeon’s preferences. I find that suture selection is easier when then the rate of absorption is incorporated into the name of the suture material  (i.e. [suture name]- short term(ST), [suture name] - mid term(MT), etc)  A simple continuous pattern is faster than a simple interrupted suture and does not increase the risk of dehiscence.  Crushing sutures are no longer recommended when closing gastrointestinal incisions because they cause foci of necrosis in the postoperative period. Sutures should be pulled just tight enough to create a seal. 

Handle With Care

All surgical procedures should be performed with Halstead’s principles in mind. A successful intestinal surgery requires that the surgeon adhere to the pillars of Halsteads’s principles of gentle tissue handling, accurate tissue apposition,  preservation of the intestinal blood supply, and meticulous dedication to asepsis, and fastidious hemostasis.  

The Almighty Submucosa

The submucosa is the holding layer of the intestine when suturing. Failure to engage the submucosa when suturing is a technical mistake that has a high potential to result in intestinal wound failure. Engaging  the submucosa when performing an intestinal closure is absolutely essential. 

The Lovely Lavage 

Although inflammation can be expected as part of the healing process, excessive inflammation can lead to a breakdown of your intestinal closure.  Peritonitis may be caused by irritants such as bacteria (e.g., perforating foreign body),  bile, blood, barium, and other substances. In patients with existing peritonitis, lavaging the abdomen post intestinal closure will dilute the presence of some those substances which cause intestinal inflammation.  This action is essential because anything that prolongs or intensifies the inflammatory phase of wound healing can increase collagenase activity. In patients without existing peritonitis, local lavage of the intestine is recommended. Avoid allowing the lavage fluid to enter the abdomen. Doing so, may potentiate peritonitis by distributing bacteria and inhibiting phagocytosis by macophages and neutrophils. Of course,  if accidental spillage of intestinal contents occurs the abdomen should be thoroughly lavaged with warm saline (the solution to pollution is dilution).

Don’t be Opposed to Appose

Everting and inverting patterns are not recommended for intestinal closure. Suture the intestinal edges together with an approximating pattern (rather than inverting or everting) in order to maximize the potential for primary intestinal wound healing.  Everting or inverting patterns inhibit fibrin deposition and the migration of enterocytes  Fibrin deposition and migration of enterocytes work best when the edges are apposed. 

The Glorious Gambee

The modified Gambee suture pattern was shown to be able to sustain a significantly higher initial leak pressure than skin staple closures and had the greatest maximum leak pressure of all enterotomy closure patterns tested in an ex vivo setting.  Although a similar study needs to be replicated in the clinical setting, and it may take slightly longer to place this suture pattern, it is worth the time investment to improve your surgical outcome.  Hand-sutured anastomosis will typically have some degree of microscopic eversion5 even with dutiful attention to apposition. However deliberately everting and interposing mucosa between the wound edges will result in focal mucosal necrosis and a prolonged inflammatory response. Biomechanically, everted closures have lower bursting strength during the lag phase of healing, suggesting an increased tendency to leak during this phase.6

The Omnipotent Omentum 

Surgical sites in the intestine can be supported with the use of omentum. Omentalization - placement of the omentum around organs or within cavities -  is a commonly utilized technique to support healing. The omentum’s healing power comes in the form of the extensive supply of blood and lymphatic vessels, it is a plentiful source of immunogenic cells and it helps with lymphatic drainage and absorption of bacteria and particulate matter.  Moreover, it encourages neovascularization and activation of macrophages. These properties help to support the early fibrin seal and improve the overall healing environment. Place an omental patch over your intestinal closures by using multiple simple interrupted sutures of rapidly absorbable monofilament suture. For end-to-end anastomotic sites, suture two portions of the caudal omental fold (the junction of the ventral and dorsal leaves) or the distal edge of an extended flap to either side of the incision line so that each covers half of the circumference of the anastomosis site.  And if you need to extend the omentum, unfolding the dorsal leaf omentum will double its length. Incising the omentum in an L-shape will give you further extension. 

Omnipresent Oxygen

Maximizing oxygen delivery to the tissues that you are closing is essential for intestinal perfusion. Correct fluid deficits preoperatively, monitor serial lactate levels in both blood and peritoneal effusion, and ensure optimal oxygen saturation during the surgery which will decrease the risk of gastrointestinal dehiscence. Applying more inspired oxygen during surgery lessens the risk of GI dehiscence by increasing oxygen delivery to the tissues. Be sure to replace fluid deficits and losses postoperatively.

Vasculature is Valuable. 

The idea of removing more intestine than initially seems necessary may not be an appealing thought but it is imperative for intestinal healing.  When performing a jejunal resection and anastomosis, the transection sites should be in close proximity to a jejunal artery.  Incise the intestine at an angle that preserves the vascularized mesenteric side which is the more vascularized portion of the intestine. When closing the mesenteric window that was created by your dissection take care not to ligate the mesenteric vessels or the jejunal arteries. 

Terrible Tension 

Tension across the anastomosis site should generally be avoided. Tension can originate from surgical technique, poor mobilization of tissues (i.e. ileocolonic anastomosis) or due to ingesta, fluid, gas, or ileus. Tension will increase the potential for intestinal dehiscence and appears to be least tolerated in the large intestine. 8

Clamp Off Contamination

Intestinal contents will likely contaminate your surgical site - especially if they are under pressure from a mechanical obstruction - unless conscientious steps are taken to avoid that potentiality..  After the surgical site has been identified, isolate the site with the use of lap sponges and move that segment off to the side away from the remainder of the abdomen. Milk intestinal contents away from the surgical site use atraumatic clamps to restrict its flow. Once the surgery has been completed, perform local lavage of the surgery site and change gloves after that portion of the procedure.

Excessive Enterotomies 

Linear foreign bodies can wreak havoc on the intestine. There can be multiple sites of intestinal attachment or regions that have perforated the intestine.  In these situations,  multiple enterotomies may need to be performed. Despite the need to perform multiple enterotomies, plan each enterotomy well to limit multiple intestinal surgical sites.8 Each additional enterotomy increases the potential for intestinal leakage and prolongs surgery time.  Ideally, an intestinal foregn body could be gently milked into the stomach and a gastrotomy performed, or gently milked into the distal colon digitally removed per rectum. 

Nutrition is Necessary 

Nothing per os (NPO) is no longer the preferred treatment post intestinal surgery.  Doing so may potentiate dehiscence, mortality and infection.  Offering enteral nutrition as soon as the patient is interested is ideal. Offering a highly digestible diet or placing a feeding tube in those patients who are reluctant to eat should be strongly considered. 

Intestinal surgery is tricky, humblin,  and, at times, very unforgiving. There are a host of other factors that make this type of surgery challenging. Hopefully by following these 13 tips, it will decrease the risk of intestinal dehiscence and improve your surgical outcomes. 

References

1. Grimes JA, Schmiedt CW, Cornell KK, Radlinksy MA. Identification of risk factors for septic peritonitis and failure to survive following gastrointestinal surgery in dogs. JAVMA. 2011;238(4):486-494.

2. . Ralphs SC, Jessen CR, Lipowitz AJ. Risk factors for leakage following intestinal anastomosis in dogs and cats: 115 cases (1191-2000). JAVMA. 2003; 223(1):73-77.

3. Wylie KB, Hosgood GH. Mortality and morbidity of small and large intestinal surgery in dogs and cats: 74 cases (1980-1992). JAAHA. 1994;30:469-474.

4. Allen DA, Smeak DD, Schertel ER. Prevalence of small intestinal dehiscence and associated clinical factors: A retrospective study of 121 dogs. JAAHA. 1992;28:70-76.

5.  Ellison GW, Jokinen MP, Park RD. End-to-end approximating intestinal anastomosis in the dog: a comparison fluorescein dye, angiographic and histopathologic evaluation. JAAHA. 1982;18:729-736.

6. Thornton FJ, Barbul A. Healing in the gastrointestinal tract. Surg Clin North Am. 1997;77(3):549-573.  

7.  G.W. Ellison, in Feline Soft Tissue and General Surgery, 2014

8. Attard JP, Raval MJ, Martin GR, et al.: The effects of systemic hypoxia on colon anastomotic healing: an animal model. Dis Colon Rectum 2005;48:1460–1470