Evaluation of the learning curve in ileal pouch-anal anastomosis surgery

Abstract

Summary background data: We define the learning curve required to attain satisfactory training in ileal pouch-anal anastomosis (IPAA) and identify possible differences in the learning curve for stapled and hand-sewn IPAA surgery. Various studies have addressed the differences in failure rate between stapled and hand-sewn IPAA, but there is no literature that evaluates the differences in attaining satisfactory training in each of these techniques.

Methods: Data were collected from 1965 patients undergoing IPAA surgery by 12 surgeons in a single center between 1983 and 2001. Using ileoanal pouch failure as the primary end point, a parametric survival model was used to adjust for case mix (patient comorbidity, preoperative diagnosis, manometric findings, and prior anal pathology). A risk-adjusted cumulative sum (CUSUM) model was used for monitoring outcomes in IPAA surgery.

Results: The 5-year ileal pouch survival was 95.6% (median patient follow-up of 4.2 years; range 0-19 years). Fifty percent of trainee staff demonstrated a learning curve in IPAA surgery. Having adjusted for case mix, trainee staff undertaking stapled IPAA surgery showed an improvement in the pouch failure rate following an initial training period of 23 cases versus 40 cases for senior staff. The learning curve for hand-sewn IPAA surgery was quantified only for senior staff who attained adequate results following an initial period of 31 procedures.

Conclusions: The CUSUM method was a useful tool for objectively measuring performance during the learning phase of IPAA surgery. With adequate training, supervision, and monitoring, the learning curve in IPAA surgery may be reduced even further.

FIGURE 1. Learning curve for IPAA surgery (stapled and handsewn anastomosis) for all staff at CCF (n = 12) comprising senior staff (n = 2), junior staff trained at CCF (n = 8), and junior staff with prior IPAA experience at other institutions (n = 2). A risk-adjusted CUSUM chart for pouch survival is displayed for a series of 1965 consecutive patients undergoing IPAA surgery. The predicted pouch survival was calculated based on a multivariate survival model based on the patient comorbidity, final histology, manometric findings, and the presence of prior anal pathology.

FIGURE 2. Learning curve for senior staff (n = 2) for stapled IPAA surgery.

FIGURE 3. Learning curve for CCF-trained junior staff (n = 8) for stapled IPAA surgery.

FIGURE 4. Learning curve for senior staff (n = 2) for hand-sewn IPAA surgery.

FIGURE 5. Learning curve for CCF-trained junior surgeons (n = 8) for hand-sewn IPAA surgery.

FIGURE 6. Kaplan-Meier survival curves illustrating the ileal-pouch survival for the initial training period of 23 cases and beyond for trainee staff.

FIGURE 7. Kaplan-Meier survival curves illustrating the ileal-pouch survival for the initial training period of 40 cases and beyond for senior staff.