Bowel obstruction following appendectomy: what is the true incidence?

Appendicitis is a common problem that is typically treated with an appendectomy. Following abdominal surgery, adhesions may form and may cause a subsequent small bowel obstruction (SBO). The purpose of our study was to determine the rate of post-appendectomy SBO in an adult population, and to observe any difference in SBO rates between open versus laparoscopic appendectomies.

All patients who underwent an appendectomy at an adult hospital in the Calgary Health Region between 1999 and 2002 were identified by using the administrative discharge database. Pathology and operative technique (laparoscopic, McBurney incision, midline laparotomy) were reviewed. Using those regional health numbers, any further admissions with a diagnostic code for bowel obstruction were identified. Medical charts (n = 1777) were reviewed to confirm the rate of post-appendectomy SBO. A logistic regression was performed to identify risk factors of post-appendectomy SBO and expressed as odds ratios (95% confidence interval).

The overall SBO rate was 2.8% over an average 4.1-year follow-up period. The risk factors for developing SBO following appendectomy for appendicitis included, perforated appendicitis (odds ratio [OR] = 3.1, 95% confidence interval [CI]: 1.5-6.6), and midline incisions (OR = 5.4, 95% CI: 2.8-10.4). Those with pathology of cancer or chronic appendicitis conferred the greatest overall risk of SBO (OR = 7.4, 95% CI: 2.7-20.3).

The rate of SBO following appendectomy in adults was 2.8%, or 0.0069 cases per person-year. The greatest risk factors for developing SBO were midline incision and nonappendicitis pathology. There is no statistically significant difference in SBO rates following laparoscopic appendectomy compared with open approaches.