Laparoscopic GB: Results and Learning Curve of a High Volume Academic Program
Abstract & Commentary
By Namir Katkhouda, MD, FACS, Professor of Surgery, Chief, Minimally Invasive Surgery, University of Southern California (USC)-Los Angeles, CA. Dr. Katkhouda is a consultant for Baxter, Ethicon, Storz, and Gore.
Synopsis: Laparoscopic Roux-en-Y gastric bypass is a complex procedure performed on a high-risk patient population. Good results can be attained with experience and volume.
Source: Shikora SA, et al. Laparoscopic Roux-en-Y gastric bypass: Results and learning curve of a high-volume academic program. Arch Surg. 2005;140:362-367.
The study is a retrospective study performed in a tertiary academic center. Seven hundred fifty consecutive morbidly obese patients undergoing surgery from March 1998 to April 2004 underwent laparoscopic Roux-en-Y gastric bypass.
Measures: Perioperative deaths and complications.
Results: The patient population was 85% women and had a mean body mass index of 47 kg/m2 (range, 32-86 kg/m2). The overall complication rate was 15% and the mortality was 0.3%. For the first 100 cases, the overall complication rate was 26% with a mortality of 1%. This complication rate decreased to approximately 13% and was stable for the next 650 patients. The incidence of major complications has also decreased since the first 100 cases. Leak decreased from 3% to 1.1%. Small-bowel obstruction decreased from 5% to 1.1%. Overall mean operating time was 138 minutes (range, 65-310 minutes). It decreased from 212 minutes for the first 100 cases to 132 minutes for the next 650 and 105 minutes (range, 65-200 minutes) for the last 100 cases.
In conclusion, Laparoscopic Roux-en-Y gastric bypass is a technically difficult operation. This review of a large series in a high-volume program demonstrated that the morbidity and mortality could be reduced by 50% with experience. The results are similar to those reported from other major centers. In addition, as reported elsewhere, the learning curve for this procedure may be 100 cases.
Shikora and colleagues from a tertiary academic center presented their series in an elegant way to assess the learning curve, basically results analyzed in quartiles. They showed what other studies have also demonstrated namely that the learning curve for laparoscopic Roux en Y gastric bypass is one of the highest in advanced laparoscopic surgery (around 100 cases). These are also the findings of Oliak and Shauer. As a comparison, the learning curve for laparoscopic hernia is around 50 cases and for laparoscopic Nissen fundoplication and laparoscopic splenectomy 20 cases.
A learning curve in surgery can be defined in many ways and my own interpretation would be "the number of cases required beyond which results are constantly reproducible with the same acceptable complication rate and operating time as published by others considered as reasonable benchmarks ( or standard of care ) in the field". In this paper, Shikora et al reduced his leak rate from 3% to 1.1%. Although the number is very good and acceptable by any standard, there is still room for a small improvement as some large series demonstrate leak rates under 1%. On the other hand, the small bowel obstruction rate of 1.1% in this series is low but a longer follow up can show a slight increase despite mastering the learning curve. Indeed, the increased incidence of SBO in laparoscopic gastric bypass surgery as shown by Capella (Archives of Surgery 2006) due to the reduced adhesion formation characteristic of laparoscopy might be due to internal hernias. Despite the closure of the internal hernia sites during the initial operation, the massive weight loss and the destruction of the sutures over time can be contributing factors.
The operating time in this study was sliced down from 212 minutes for the first 100 cases to 132 minutes for the next 650. Even after 750 patients, it was still possible to reduce in the last 100 cases by half an hour. More operating room efficiency and increased knowledge of tips and tricks can contribute to these improved results.
The final important question that comes to mind is the issue of training in academic centers. The mandatory new requirements for training in advanced laparoscopy for residents and the number of bariatric fellowships will have without a doubt an impact on outcome data. The real challenge will be to find ways to reproduce the same acceptable complication rates and operating room times in a teaching environment as in the hands of surgeons beyond their learning curve and avoid potential yoyo results ( worse at the beginning of the academic year and improved at the end).