Learning curve in videothoracoscopic thymectomy: how many operations and in which situations?

Abstract

Videothoracoscopic learning curve is known to vary among different surgeons, and may be influenced by patients and various situations. We aimed to analyze the learning curve of a surgeon in videothoracoscopic thymic surgery for myasthenia gravis. This is a descriptive single-center study using collected clinical data from 90 patients undergoing videothoracoscopic thymic surgery between June 2002 and September 2006. Cumulative summation (CUSUM) model was used to evaluate the learning curve for videothoracoscopic thymectomy operations. Unsuccessful situations were accepted as longer operation time, surgeon-related open conversions, readmissions and postoperative complications. Factors affecting longer operation time (patients with operation time longer than the average) and longer postoperative stay (patients with postoperative hospital stay longer than average) were analyzed. Body mass index (BMI) was the only predictor of longer operation time (23.04+/-2.93 vs 25.61+/-2.70 (p=0.001) independent samples test). The amount of prescribed pyridostigmine was the only factor for longer hospital stay (213.3+/-101.5 mg vs 270. 0+/-122.6 mg (p=0.044) Mann-Whitney U-test). CUSUM analysis demonstrated a learning curve with success rates of 80%, 90% and 98%, respectively in the first 30 patients, the next 31-60 patients and after 60 patients. Median operative time declined with surgeons' experience (p<0.001). A chest surgeon can have a high success rate in videothoracoscopic thymectomy (98%) after 60 operations.