Abstracts
1998 Digestive Disease Week

#1052

CHOLANGIOGRAPHY DURING LAPAROSCOPIC CHOLECYST-ECTOMY: CUMULATIVE SUM ANALYSIS OF AN INSTITUTIONAL LEARNING CURVE. M. Molloy, S.B. Archer, P.O. Hasselgren, B.J. Dalton, and R.H. Bower, Surgical Service, VA Medical Center, Cincinnati, OH.

The ability to perform an intraoperative cholangiogram (IOC) during laparoscopic cholecystectomy (LC) is an essential technical skill for the laparoscopic biliary surgeon. We performed a cumulative sum (CUSUM) analysis of the first 97 IOCs attempted during LC at our facility to determine the number of attempts required to successfully obtain an IOC in 95% of cases. The CUSUM (Sn) for a series of observations is defined as:

Sn = (Xi - X0 ),

where Xi = 0 for a success, Xi = 1 for a failure, and X0 is the acceptable failure rate (in this case 0.05). This function is plotted against the number of cases performed. When the resulting curve plateaus

between calculated control limits, the acceptable failure rate is not being exceeded. The CUSUM curve for obtaining an IOC in 95% of attempts at our facility is shown below:

Forty-six cases were required to achieve a success rate of 95% for IOC during LC. Similar analyses showed that 85% and 90% success rates were achieved at 16 and 25 cases respectively. This form of analysis is potentially a useful tool for estimating the number of attempts required to achieve a desired success rate when learning new procedures.

Copyright 1996 - 1998, SSAT, Inc. Revised 29 June 1998.