Analysis ofCUSUM learning curve of robotic intracorporeal Studer's orthotopic neobladder

Cheng Qiang; Gao Fan; Chen Wenzheng; Ai Qing; Jiang Bin; LuYin; Tang Jinlu; Shen Dan; Li Hongzhao

doi:10.19558/j.cnki.10-1020/r.2023.06.002

Abstract：Objective:To investigate the learning curve of robotic intracorporeal Studer's orthotopic neobladder(RISON).Methods:The operation time for RISON performed at the Senior Department of Urologyof the Third Medical Center of PLA General Hospital from March 2018 to June 2022 was analyzed using cumulative sum analysis(CUSUM).The CUSUM learning curve was fitted,and its goodness of fit was assessed using R2.Operation time,intraoperative bleeding,number of lymph node dissections,early postoperative complications,postoperative hospital andfollow-up situation were compared across different stages of the learning curve.Additionally,the number of opera-tions required from the initial learning stageto reach proficiency stage was summarized.Results:A total of 62 patients were included in this study,including 60 males(96.8%)and 2 females(3.2%),with ages ranging from 26 to 69 years and a median age of 58 years.The median BMI was recorded as 24.8 kg/m2.9 patients(13.2%)received neo-adjuvant therapy prior to surgeries.The operation time for all RISON procedures ranged from 3.5 to 10 hours,with an average of(6.32±1.48)hours.No conversions were observed within the entire group.CUSUM(n)=OT(n)-OT(mean)+CUSUM(n-1)demonstrated the highest goodness off it when modeled by cubic curves(P＜0.001,R2= 0.864),with fitting equation:CUSUM(n)=0.001n3-0.099n2+2.466n-3.669(where n represents the number of cas-es).The fitted curve reached its peak at 17 cases.Before reaching 17 cases,the CUSUM curve exhibited a continuous upward trend,while after surpassing 17cases,it demonstrated a consistent decline.Based on this demarcation point,the learning curve can be divided into two distinct stages:the initial learning stage encompassing cases one to seven-teen and the subsequent proficiency stage beyond 17 ases.Compared with the learning and the proficiency stage,there was no statistical difference in baseline data between the two groups,and there were statistically significant differenc-es in operation time(P=0.003),intraoperative blood loss(P=0.002),postoperative feeding time(P=0.005),and the number of drainage tubes(P＜0.001).Conclusion:The CUSUM method was employed to analyze the learning curve associated with RISON.The results showed that the cumulative number of operations required to master the technique was 17.