ABSTRACT
Objective To investigate the learning curve of Da Vinci robot-assisted laparoscopic radical gastrectomy for gastric cancer.Methods The retrospective cohort study was conducted.The clinicopathological data of 42 patients who underwent Da Vinci robot-assisted radical gastrectomy for gastric cancer in the First Affiliated Hospital of Xi'an Jiaotong University from October 2017 to August 2018 were collected.There were 30 males and 12 females,aged from 36 to 84 years,with an average age of 59 years.The learning curve was evaluated using the cumulative sum (CUSUM) analysis and the best fitting curve method.According to the minimum number of surgeries required to cross the learning curve,the patients were divided into learning stage group and mastery stage group.Then general data and surgical efficacy of the two groups were compared.Observation indicators:(1) surgical situations;(2) results of CUSUM analysis;(3) comparison of general data between the two groups;(4) comparison of surgical efficacy between the two groups;(5) follow-up.Patients were followed up by outpatient examination or telephone interview to detect the postoperative complications,tumor recurrence and metastasis up to February 2019.Measurement data with normal distribution were presented as Mean±SD,and comparison between groups was done using the independent sample t test.Count data were represented as absolute number,and comparison between groups was analyzed using the chi-square test or Fisher exact propability.Comparison of ordinal data between groups was analyzed using the Mann-Whitney U test.Results (1) Surgical situations:all the 42 patients underwent Da Vinci robot-assisted radical gastrectomy for gastric cancer successfully,without conversion to open surgery or perioperative death.Fourteen out of 42 patients underwent Da Vinci robot-assisted total radical gastrectomy and 28 underwent Da Vinci robot-assisted distal radical gastrectomy.The operation time and docking time were (213±31)minutes and (26± 11)minutes.The operation time and docking time had a tendency to decreasing as the surgical cases increasing.(2) Results of CUSUM analysis.The CUSUM learning curve were best modeled as a polynomial with equation:CUSUM (operation time)=0.016 9X3-1.913 3X2+ 50.985X-16.595,CUSUM (docking time) =0.012 8X3-1.070 7X2 + 22.189X-23.097 respectively (X means the surgical case).The P value of fitting test of models was ＜ 0.05,with goodness-of-fit (R2) as 0.960 and 0.985.The CUSUM learning curve of operation time reached its peak when the number of surgical cases accumulated to the 19th case.Nineteen cases were the minimum number of surgeries required to cross the learning curve.Similarly,The CUSUM learning curve of docking time reached its peak when the number of surgical cases accumulated to the 14th case,and 14 cases were the minimum number of surgeries required to skillfully master robot installation across the learning curve.(3) Comparison of general data between the two groups:patients were divided into learning stage group and mastery stage group with 19 cases as the cut-off point.Males,females,age,body mass index (BMI),cases in grade 1,2,3 of American society of anesthesiologists (ASA),cases with previous abdominal surgery history,cases with basic diseases,cases in T1,T2,T3,T4 stages of preoperative ultrasonic gastroscopic tumor T staging,maximum tumor diameter,cases in Ⅰ,Ⅱ,Ⅲ stages of postoperative clinical staging,cases with total gastrectomy and distal gastrectomy (surgical method) were 14,5,(60± 13)years,(23.7±2.9)kg/m2,1,16,2,3,8,5,3,3,8,(4.1±3.5)cm,6,7,6,10,9 in the learning stage group,and 16,7,(58±10)years,(23.7±1.3)kg/m2,1,17,5,2,14,3,6,9,5,(4.7±2.7)cm,8,9,6,18,5 in the mastery stage group,respectively.There was no significant difference in the sex,age,BMI,ASA score,basic diseases,preoperative ultrasonic gastroscopic tumor T staging,maximum tumor diameter,postoperative clinical staging,and surgical method between the two groups (x2 =0.086,t =0.475,-0.007,Z =-0.884,x2 =1.469,Z =-0.301,t =-0.651,Z =-0.079,-0.236,x2 =3.076,P ＞ 0.05).There was no significant difference in the previous abdominal surgery history between the two groups (P ＞ 0.05).(4) Comparison of surgical efficacy between the two groups:operation time,volume of intraoperative blood loss,number of lymph nodes harvested,time to first liquid food intake,cases with postoperative complications and duration of postoperative hospital stay were (230±25) minutes,(176± 103) mL,21±7,(5.1 ± 2.0) days,2,(9.3± 2.5)days in the learning stage group,and (191±18) minutes,(95±41)mL,21±6,(4.7±1.7)days,3,(8.4± 2.1)days in the mastery stage group,respectively.There were statistically significant differences in the operation time and volume of intraoperative blood loss between the two groups (t =5.951,-3.359,P＜0.05).There was no statistically significant difference in number of lymph nodes harvested,time to first liquid food intake,and duration of postoperative hospital stay between the two groups (t =-0.120,0.538,1.303,P＞0.05).There was no significant difference in the cases with postoperative complications between the two groups (P＞0.05).(5) Follow-up:all the 42 patients were followed up for 6-16 months,with a median time of 11 months.No serious long-term complications,tumor recurrence and metastasis or death occurred during the follow-up.Conclusions The CUSUM learning curve of Da Vinci robot-assisted radical gastrectomy for gastric cancer can be divided into the learning stage and the mastery stage.It is suggested that the surgeons need to finish 19 cases or more to master Da Vinci robot-assisted radical gastrectomy for gastric cancer.
ABSTRACT
Objective To determine the relationship between the theory and actual displacement of the urine flow rate meter calibration device gear pump, and to construct a model between actual and theory displacement, in order to obtain actual displacement via theory displacement. Methods The weight of the standard water flow in each flow rate was measured by B2000S digital scales,and the scatter plot between the theory displacement and actual displacement was drawn to find the best fitted curve;then the MATLAB Curve Fitting Tool was used to obtain the best quasi relational equation. Results The error between the fitted displacement and the actual displacement of the gear bump was 1.494% in maximum and-0.010% in minimum, far less than 5% of the requirements for urinary flow meter measurement. Conclusion Based on regression analysis, the relationship between the theoretical displacement and actual displacement of the flow rate meter calibration device is established,the fitting error is small,and the method is simple and easy to achieve.