Open surgery for inflammatory bowel disease (IBD) has been known to carry a high risk of incisional hernia, but the risk factors have not been well understood.

A review of 1,000 operations performed over nearly 40 years at a high-volume, nationally recognized center has identified five patient factors that can raise the risk of incisional hernia in these operations by 50% or more, according to a study published in the Annals of Surgery.

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The study followed the patients for an average of 8 years after their operations, which were performed between January 1976 and December 2014 at Mount Sinai Medical Center in New York. The overall incidence of incisional hernia was 20%-21% for patients with ulcerative colitis and 20% for those with Crohn’s disease.

Half of these patients developed an incisional hernia less than 2 years after the index surgery and 75% in less than 4 years.

The researchers identified the following statistically significant risk factors for incisional hernia: wound infection (hazard ratio, 3.66; P less than .001); hypoalbuminemia (HR, 2.02; P = .002); previous bowel resection (HR, 1.6; P = .003); ileostomy created at time of procedure (HR, 1.53; P = .01); and a history of smoking (HR, 1.52; P less than .013). Other risk factors to lesser degrees are body mass index at time of surgery (HR, 1.036; P = .009); age at time of surgery (HR, 1.021; P less than .001), and age at disease onset (HR, 1.018; P less than .001).

Lead author Tomas Heimann, MD, and his coauthors pointed out that this study population had severe levels of disease. Almost half of the patients had severe intractable disease that had resisted medical treatment. More than a quarter of these patients had received preoperative steroid therapy within 6 weeks, and 15% had received recent immunosuppressive therapy. Almost 80% were either anemic or had hypoalbuminemia or both. The average duration of disease was 12 years. More than half had undergone previous bowel surgery – “often lengthy and difficult” – with many patients suffering from fistulae, abscesses, and dense adhesions. “These factors were more likely to predispose patients to develop wound infections and delayed healing resulting in incisional hernia in one-fifth of our patients,” Dr. Heimann and his coauthors noted.

A somewhat unexpected finding was that immunosuppressive therapy and steroids were not linked to incisional hernia in these patients.

Prophylactic mesh placement in patients with IBD is impractical because of the risk of infection it carries, Dr. Heimann and his coauthors said.

Dr. Heimann and his coauthors reported having no financial disclosures.

SOURCE: Heimann T et al. Ann Surg. 2018 Mar;267(3):532-6.

Defining incisional hernia risk in IBD surgery