Crude complication rate is not an accurate marker of a surgeon's skill: A single surgeon retrospective series of 1060 procedures for colorectal endometriosis.

Objective: To assess the relationship between the rate of postoperative bowel fistula and surgeon experience.

Design: Retrospective study.

Setting: Two referral centers.

Patients: 1060 women managed for colorectal deep endometriosis by one gynecologist surgeon from January 2005 to March 2020.

Interventions: Shaving, disc excision and segmental colorectal resection.

Main Outcome Measures: Rate of bowel fistula stratified according to 4 time periods: P1 from 2005 to 2009, P2 from 2010 to 2014, P3 from 2015 to June 2018 and P4 from September 2018 to March 2020.

Results: 68 patients (6.4%) were managed during P1, 299 patients (28.2%) during P2, 422 patients (39.8%) during P3 and 271 patients (25.6%) during P4. Both diameter of rectal infiltration and rate of complex surgical procedures progressively increased from P1 to P4. Bowel fistula rate was comparable between all 4 time periods, respectively 2.9, 3.3, 4 and 4.4%. Logistic regression model revealed that risk of fistula decreased when shaving was performed when compared to segmental resection (adj OR 0.1, 95% CI 0-0.5) and increased when deep endometriosis nodules also involved sacral roots (adjOR 4.9, 95%CI 1.8-13.3) and infiltration of the vagina (adj OR 3, 95%CI 1.3-7). No statistically significant relationship was found between surgery time period and risk of fistula.

Conclusion: Crude rates of bowel fistula following surgical management of deep endometriosis infiltrating the colon and the rectum are not an accurate marker of surgeon expertise and should be considered in conjunction with expected higher risks related to challenging procedures performed by experienced surgeons.