2.3 Study protocol
This study protocol was approved by the ethics committee of Zhongshan Hospital Fudan University and was consistent with the Declaration of Helsinki . All included patients signed an informed consent approved by the ethics committee. Data collection was performed by trained staff (two people). The trained staff, however, were not informed of the purpose of this study.
Baseline and surgical characteristics, and perioperative results were obtained from our institutional database and were reviewed using a standard data collection form. Patients were regularly followed up at 3 and 6 months following surgery, respectively, and thereafter at 6-month intervals. Follow-up data were obtained by a clinic visit, WeChat, or telephone. In addition, the incidence of major adverse events per surgeon was calculated and compared. The details of baseline characteristics, surgical characteristics, perioperative results, follow-up results, and major adverse events are shown in the additional file 1.