General information: The clinical data of patients undergoing laparoscopic pancreaticoduodenectomy in the Department of Hepatobiliary Surgery, Shandong Provincial Hospital from June 2018 to June 2022 were retrospectively analyzed. Inclusion criteria: (1) Successful operation without laparotomy; (2) Preoperative imaging showed tumors around the pancreas head and ampulla without distant metastasis. Exclusion criteria: (1) absence of perioperative data; (2) conversion to laparotomy.
Preoperative examination and preparation: (1) Preoperative examination: routine blood examination, liver function examination, blood biochemistry examination, electrocardiogram examination, chest radiograph examination, upper abdominal three-stage enhanced CT or MRI examination. If the patient is old or complicated with cardiopulmonary disease, cardiac ultrasound, lung function and other relevant tests should be performed according to the specific conditions. (2) Preoperative preparation: Informed consent for surgery was signed. If the total bilirubin was more than 400µmol/L before surgery, percutaneous hepatic aspiration and biliary drainage were performed to reduce yellow.
Related to surgery: (1) Surgical methods: The 5-hole method was used to establish the abdominal operating hole, perforate the gastrocolic ligament, separate and dissect the omental sac to expose the pancreas, dissect the free gastric antrum and duodenal bulb, separate and ligate the right gastroepiploic vessel. The superior mesenteric vein was searched along the right gastromental vein to establish a tunnel behind the neck of the pancreas. The right blood vessel of the stomach was separated and ligated, and the gastric wall was severed 2cm from the pylorus with a cutter closure. The jejunum was severed approximately 15cm from the ligament Qu with a cutter closure. The capsule was cut open along the upper margin of the pancreas neck, lymph nodes around the common hepatic artery were dissected, the hepatoduodenal ligament was skeletal, the gastroduodenal artery was exposed and ligated, and neurolymphatic tissue was dissected. The lower segment of the hepatic duct was transected, the distal end was ligation and closed, and the gallbladder was excised. The lower margin of the pancreas was detached, and the neck of the pancreas was severed with an ultrasonic knife. The superior mesenteric vein and splenic vein were suspended. The uncinate process of the pancreas and its mesangium were removed near the right side of the superior mesenteric artery. The closed jejunum was lifted over the mesangium of the colon, and end-to-side anastomosis of the pancreatic duct and jejunum mucosa was performed. Pancreatoenterostomy was anastomized by "Hong's one-needle method", and support tubes were placed in the main pancreatic duct. End-to-side anastomosis of the hepatic duct and jejunum was performed approximately 8cm away from the anastomosis, and side-side gastrojejunal anastomosis was performed approximately 45cm away from the bilioenteric anastomosis. Double cannulae were prearranged for pancreaticojejunostomy and biliojejunostomy. A 3–5 cm incision was made along the midline of the upper abdomen to remove the specimen. (2) Intraoperative indicators: the time from the beginning of skin resection to the end of suture was calculated as the operating time, and the amount of intraoperative blood loss was recorded. (3) Postoperative indicators: incidence of pancreatic fistula, biliary fistula, gastric fistula, gastroparesis, postoperative exhaust and feeding time, postoperative bleeding, abdominal infection, reoperation and perioperative death were recorded. Perioperative time was defined as the time between admission and discharge. According to the 2016 update of the International Study Group on Pancreatic Surgery (ISGPS), postoperative pancreatic fistula(POPF) grade: the "Grade A pancreatic fistula" in the original grade is redefined as "biochemical leakage (BL)", which means that serum amylase is more than 3 times the upper limit of normal serum amylase in the institution. "Grade B pancreatic fistula" means continuous drainage for more than 3 weeks, or related clinical measures to control postoperative pancreatic fistula, or percutaneous or endoscopic drainage, or angiography due to bleeding, or infection without organ failure; "Grade C pancreatic fistula" means repeated surgery, or organ failure, or death [11][12][13].
Multiple linear regression
Multiple linear regression methods were used to screen for factors affecting operating time. Assign independent variables to data that are classified variables, such as gender and main admission symptoms. Calculate standard operating time.
CUSUM analysis was used to construct the learning fitting curve: CUSUM method is a time-weighted control graph method, which has been used for learning curve detection in recent years. This method first calculates the degree of deviation between the observed value of each sample and the target value, and calculates the accumulation and CUSUM by summing method. Formula is as follows: CUSUM=\({\sum }_{\text{i}\text{=1}}^{\text{n}}\text{(}\text{X}\text{i}\text{-}\text{u)}\),“Xi” represents the observed value for each patient (using operative time and intraoperative blood loss), “n” represents the surgical sequence number, “u” represents the mean value of this observation. The surgical serial number is taken as the abscissa, CUSUM value as the ordinate, and the fitting curve drawing is calculated, with P < 0.05 judge fitting success to the fit of the fitting coefficient \({R}^{2}\) judgment, the best model choose \({R}^{2}\) most close to 1.
Statistical processing
SPSS25.0 software was used for statistical analysis. The learning curve is drawn using R software version 4.1.2.. Measurement data conforming to the normal distribution use (x̄ ± s) representation, and t- test was used for comparison between groups. Measurement data with non-normal distributions were represented by M(Q1,Q3), and the rank sum test was used for comparison between groups. Frequency data (classified data) is represented by the number of cases (%), and comparison between groups using test or Fisher's exact probability method. All results were considered statistically significant with P < 0.05.