2.1. Patient Selection and Study Design. From April 2006 to February 2019, a total of 39 patients whom LPG was performed at Oita University Hospital were enrolled in this study. Nine patients underwent LPG with conventional method between April 2006 and March 2009 (Conventional group). And, 30 patients underwent LPG with novel method between April 2009 and February 2019 (Novel group). Diagnosis of all patients was made according to preoperative endoscopy, endoscopic ultrasonography, upper gastrointestinal series, and abdominal computed tomography (CT). The staging of the tumor was classified according to the Japanese Classification of Gastric Carcinoma by the Japanese Gastric Cancer Association, 3rd English edition [7]. Our indication for this LPG is proximal gastric cancer, for which the preoperative diagnosis is clinical T1N0M0 or clinical T2N0M0 gastric cancer located in the upper one- third of the stomach without esophageal invasion, and it was considered that at least two-thirds of the stomach could be preserved preoperatively in all cases. Differentiated types included papillary and tubular adenocarcinomas, and undifferentiated types included poorly differentiated adenocarcinoma, signet ring cell carcinoma, and mucinous adenocarcinoma. All tissues were examined by expert pathologists.
This was a retrospective study using surgical and clinicopathological records and follow-up data, approved by the Institutional Review Board of Oita University Hospital, Oita, Japan (Approval No. 542).
2.2. Surgical Procedure of LPG with long and narrow gastric tube reconstruction: novel method. LPG with D1+ lymph nodes dissection (nodes no. 1, 2, 3, 4sa, 4sb, 7, 8a and 9) were performed according to the Japanese gastric cancer treatment guidelines 2018 (5th edition) [7]. During the laparoscopic procedure, the upper part of the stomach is fully mobilized with perigastric and suprapancreatic lymph nodes dissection. The vagus nerves, especially, the hepatic and the peripheral pyloric branches, are always preserved. And then the abdominal esophagus is transected. After a mini-laparotomy is created, the entire stomach is pulled outside. A long and narrow gastric tube (more than 20 cm in length, 3 cm width) with widening of the proximal side (6cm in length) of the gastric tube like a cobra’s head is created using by linear stapler (Figure 1, 2). A cobra’s head gastric tube is made for formation of the pseudo-fundus. A pyloroplasty is not always performed. After the pneumoperitoneum is recreated, esophagogastrostomy is performed by direct anastomosis with overlap method between the posterior wall of the esophagus and anterior wall of the gastric tube using a 45-mm linear stapler under laparoscopic view (Figure 3). The entry hole for anastomotic stapler is closed with a continuous suture by a synthetic absorptive thread with a barb. To prevent esophageal reflux, both the right and left ends of the esophageal wall are fixed to the gastric wall with laparoscopic interrupted sutures (Figure 4). And, we always perform the suture fixation between bilateral crus of diaphragm and esophagus wall for preventing the torsion of the gastric tube (Figure 5, 6).
2.3. Surgical Procedure of LPG with gastric tube reconstruction: conventional method.
As for all cases in LPG with conventional method, direct anastomosis between the esophagus and gastric tube by a circular stapler was performed. After the upper part of the stomach was fully mobilized, the abdominal esophagus was transected. The stomach was cut between the points of the distal three fourths of the lesser curvature and a half of the greater curvature, and a long gastric tube measuring 15 cm in length and 4 cm in width was made. The lower esophagus is anastomosed to the posterior wall of the gastric tube with a circular stapler inserted through a small opening made on the anterior wall of the stomach. Direct anastomosis between the esophagus and gastric tube was completed.
2.4. Evaluation of short- and long-term outcomes. Short- and long-term outcomes of 30 patients who underwent LPG with novel method were compared with those of 9 patients who underwent LPG with conventional method. We examined the following clinicopathological characteristics of all patients undergoing LPG, such as age, sex, body mass index (BMI), clinicopathological findings including tumor size, clinical TNM factors, pathological TNM factors. Surgical findings, such as operation time and blood loss, were also examined. We also examined the following data to evaluate the short- and long-term outcomes, such as postoperative mortality, start of diet food, postoperative hospital stay, postoperative complications defined as any condition requiring conservative or surgical treatment occurring within 30 days after the operation, including anastomotic leakage, anastomotic stenosis, pancreatic fistula, stasis, and postoperative general complications including respiratory, cardiovascular, and renal disorders, and enterocolitis. Postoperative complications were classified according to the Clavien-Dindo (CD) classification [18]. Patients were routinely followed-up by clinical visits every 6 months for 5 years at least. They consisted of a clinical examination, blood tests, thoraco-abdominal CT examination. Followed-up endoscopy was routinely performed at 1 year after operation to evaluate reflux esophagitis, classified according to the Los Angeles classification [19].
2.5. Statistical analysis. Quantitative data are given as the median and range. Differences between the two groups were assessed by the chi-square test, Fisher’s exact test, or Mann-Whitney U test as appropriate. A P-value < .05 was considered statistically significant. These analyses were carried out using SPSS ver. 24 (SPSS Inc., Chicago, IL, USA).