Equis ISSN 2398-2977

Abdomen: adhesions

Contributor(s): David Moll, Carla Sommardahl, Graham Munroe


  • Cause: common complication of abdominal surgery, peritonitis or possibly strongyle migration.
  • Signs: none or colic - varies from mild discomfort (following surgery) to severe (if volvulus or herniation involved).
  • Diagnosis: history, signs, laparotomy.
  • Treatment: mild cases → NSAIDs; severe cases → surgery.
  • Prognosis: depends on extent of adhesion and damage to bowel. One of the limitations on survival rate post-abdominal surgery.



  • The true incidence of post-operative adhesions is not really known as the reported studies have differences in their protocols for inclusion, in the population studied, and the way the results are reported. Most studies report the incidence based on those cases taken back to a repeat laparotomy, whereas the true incidence, based on a PM study of all originally operated cases, is probably considerably higher.
  • Reported incidences have varied as widely as 1.5-33% of all post-operative colic surgery cases. In general, an incidence of between 5-15% is commonly cited in many studies which look across a wide range of colic surgery.

Predisposing factors




  • Fibrous and omental adhesions are a normal response after peritoneal injury and inflammation. Many cause no clinical problems. They can become a problem if the fibrinous adhesion matures into a fibrous one that restricts, compresses or distorts the gut leading to obstruction of normal passage of ingesta. Some can lead to intestinal incarceration, strangulation and volvulus Gastrointestinal: small intestine - torsion. All these adverse effects on gut function will present with varying degrees of abdominal pain or colic Abdomen: pain - adult.
  • Injury or inflammation of the peritoneal membrane stimulates procoagulant activity within it, which is characterized by serofibrinous exudate secretion and subsequent deposition of fibrin. This fibrin matrix provides access for healing tissues to repair and re-establish the damaged peritoneum. Once this occurs there are local peritoneal fibrinolytic enzymes that can lyse the fibrin or fibrinous adhesions within 48-72 h. If the damage or inflammation is more severe, then the fibrin matrix is not lysed before it matures into fibrinous adhesions between adjacent viscera or peritoneal surfaces. Peritoneal fibrinolytic activity may be depressed by intestinal ischemia and inflammation caused by distension and strangulation, surgical trauma and excessive handling.
  • All sorts of biological processes such as coagulation, fibrinolysis, kinin/bradykinin, arachidonic acid metabolism, and complement activation are involved in adhesion formation. The fibrinolytic system is the main modulator through its control of fibrin lysis under the action of the enzyme plasmin. Plasmin is derived from plasminogen via tPA (tissue plasminogen activator), the latter also being controlled by plasminogen activator inhibitors. The precise role of this fibrinolytic control system in the lack of fibrinolysis and therefore formation of mature adhesions is not yet known.
  • The most common sites for adhesions are between loops of small intestine, and between the cecum and ventral body wall.


  • Horses with adhesions that cause partial obstruction of the intestine often begin to show colic clinical signs 5-7 days post-operatively. Strangulation and incarceration, related to adhesions, often occur later on in the horse's life.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Munsterman A S, Kottwitz J J & Reid Hanson R (2016) Meta-Analysis of the effects of adhesion barriers on adhesion formation in the horse. Vet Surg 45 (5), 587-595 PubMed.
  • Alonso Jde M et al (2014) Peritoneal response to abdominal surgery: the role of equine abdominal adhesions and current prophylactic strategies. Vet Med Int Article ID 279230 PubMed.
  • Claunch K M & Mueller P O E (2012) Treating intra-abdominal adhesions: The surgeon's dilemma. Equine Vet Educ 24 (11), 552-555 WileyOnline.
  • Kelmer G (2009) Update on recent advances in equine abdominal surgery. Vet Clin North Am Equine Pract 25 (2), 271-282 PubMed.
  • Fogle C A et al (2008) Analysis of sodium carboxymethylcellulose administration and related factors associated with postoperative colic and survival in horses with small intestinal disease. Vet Surg 37 (6), 558–563 PubMed.
  • Gorvy D A, Barrie Edwards G & Proudman C J (2008) Intra-abdominal adhesions in horses: a retrospective evaluation of repeat laparotomy in 99 horses with acute gastrointestinal disease. Vet J 175 (2), 194–201 PubMed.
  • Mair T S & Smith L J (2005) Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 2: short-term complications. Equine Vet J 37 (4), 303–309 PubMed.
  • Mair T S & Smith L J (2005) Survival and complication rates in 300 horses undergoing surgical treatment of colic. Part 1: short-term survival following a single laparotomy. Equine Vet J 37 (4), 296–302 PubMed.
  • Hay W P et al (2001) One percent sodium carboxymethylcellulose prevents experimentally induced abdominal adhesions in horses. Vet Surg 30 (3), 223–227 PubMed.
  • Mueller P O et al (2000) Effect of carboxymethylcellulose and a hyaluronate-carboxymethylcellulose membrane on healing of intestinal anastomoses in horses. Am J Vet Res 61 (4), 369–374 PubMed.
  • Mueller P O et al (2000) Evaluation of a bioresorbable hyaluronate-carboxymethylcellulose membrane for prevention of experimentally induced abdominal adhesions in horses. Vet Surg 29 (1), 48-53 PubMed.
  • Boure L, Marcoux M, Lavoie J P & Laverty S (1998) Use of laparoscopic equipment to divide abdominal adhesions in a filly. JAVMA 212 (6), 845-847 PubMed.
  • Kuebelbeck K L, Slone D E & May K A (1998) Effect of omentectomy on adhesion formation in horses. Vet Surg 27 (2), 132–137 PubMed.
  • Southwood L L, Baxter G M, Hutchison J M & Shuster R (1997) Survey of diplomates of the American College of Veterinary Surgeons regarding postoperative intra-abdominal adhesion formation in horses undergoing abdominal surgery. JAVMA 211 (12), 1573-1576 PubMed.