Small bowel obstruction after appendicectomy.

BACKGROUND

This study analysed the risk of surgically treated small bowel obstruction after open appendicectomy.

METHODS

This was a historical cohort study of 245 400 patients who underwent open appendicectomy and population-based matched controls, identified by linkage of computer registries. Analyses were made with the life-table technique, Kaplan-Meier plots and Cox proportional hazards regression analysis.

RESULTS

The cumulated risk of surgically treated small bowel obstruction after appendicectomy was 0.41 per cent after 4 weeks, 0.63 per cent after 1 year and 1.30 per cent after 30 years of follow-up, compared with 0.003 per cent at 1 year and 0.21 per cent after 30 years of follow-up among the non-operated controls. The highest risk was found after operation for other diagnoses (adjusted hazard ratio 5.2 (95 per cent confidence interval 4.6-5.8)), followed by operation for perforated appendicitis (adjusted hazard ratio 3.5 (3.1-3.8)), non-specific abdominal pain (adjusted hazard ratio 2.6 (2.3-3.0)) and mesenteric lymphadenitis (adjusted hazard ratio 2.4 (2.0-2.8)) compared with operation for non-perforated appendicitis. The relation with age was J shaped, with the lowest risk at 20-39 years. Women had a slightly lower risk than men.

CONCLUSION

The risk of postoperative small bowel obstruction needing surgical treatment after open appendicectomy is lower than previously thought. Perforated appendicitis, negative appendicectomy and high age are the risk factors.