An Optimal Surgical Approach for Suprapancreatic Area Dissection in Laparoscopic D2 Gastrectomy with Complete Mesogastric Excision

Background During the radical operation, the suprapancreatic area is featured by anatomical complexity, and the lymph node dissection for this area is technically difficult and demanding.(1-4) Previously, we have demonstrated the presence of disseminated cancer cells in the mesogastrium(5,6) and presented a mesogastrium model for gastrectomy.(7) As a consequence, laparoscopic D2 lymphadenectomy plus complete mesogastric excision (D2+CME) was proposed as a new concept in the surgical treatment of advanced gastric cancer.(8) D2+CME procedure has been shown to be associated to lower number of free intraperitoneal cancer cells and with a better disease-free survival than conventional D2 gastrectomy.(9) Under the concept of mesogastrium model, the proposed D2+CME procedure could help surgeons better define the anatomical boundaries of suprapancreatic mesogastrium, thus using it to achieve a complete and standard excision of the suprapancreatic area dissection. Here, we briefly present perioperative results of our case series with the laparoscopic curative subtotal gastrectomy and D2+CME with a R0 resection and present a video to detail the technical aspects of a laparoscopic D2+CME approach for suprapancreatic area dissection. Methods All patients in this study underwent laparoscopic subtotal gastrectomy (D2+CME) with a curative R0 resection. This study was approved by the Tongji Hospital Ethics Committee (Unique Reference Number: TJ-IRB20180811). The procedures in the video are described as follows. Based on our previous mesogastrium model (also named "Table model", Supplemental Figure 1), the suprapancreatic mesogastrium is attached to the lesser curvature or the posterior gastric wall and extended to the suprapancreatic area, respectively.(7) Surgeon stands on patient left side, and the assistant lifts the stomach upward and cephalic to expose the suprapancreatic mesogastrium including left gastric mesentery (LGM), right gastric mesentery (RGM) and posterior gastric mesentery (PGM). First of all, towards to the left side of the suprapancreatic area, the "tri-junction" point of LGM is exposed. Using an energy devise, surgeon opens serosa layer and identifies the retrogastric space. The LGM and PGM are mobilized bluntly, between which a fusion retrogastric space is revealed. Both the LGM and PGM are covered by smooth and shiny surfaces of fascial propria and regarded as the "meso-bed" mutually. Secondly, at the inner side of duodenum, surgeon bluntly separates the adjuvant tissues along gastro-duodenal artery (GDA) upward and exposes right gastric mesentery (RGM). Next, after mobilizing the left gastric mesentery, surgeon removes the adipose tissue adherent to the common hepatic artery (CHA) and exposes the root of the left gastric artery after dissecting the perivascular sheath with triple-clips. Then, surgeon dissects RGM along the CHA and portal vein (HPV) towards the right side of the suprapancreatic area; afterwards, the right gastric vessels and RGM are identified and ligated. Lastly, the superior border of splenic vessels is dissected. The anterior lobe of the PGM is raised up with ligated posterior gastric vessels. Remarkably, posterior gastric vessels may be absent in some cases. Reconstruction of the alimentary tract is Roux-en-Y method. Standard recovery protocols are followed in postoperative treatments. Results Between August 28th 2017 and December 27th 2018, 107 patients receiving laparoscopic curative subtotal gastrectomy (D2+CME) with a R0 resection were retrospective collected in this study. After exposing the suprapancreatic mesogastrium including RGM, PGM and LGM with D2+CME procedure, the LNs and fat tissues around 7, 9, 8a, 12a and 11p were removed en bloc in all patients. This study recruited 67 males and 40 females. The median age was 55 years, with body mass index (BMI) 23.0 kg/m(2) (Supplemental Table 1). The median number of retrieved regional lymph nodes was 31 (range 25-41), including 22 (range 17-27.5) suprapancreatic lymph nodes. The median volume of blood loss was 14 ml (range 6-34). The median total operation time was 287 min (range 265.5-313.5) and laparoscopic surgery time was 132 min (range 116-142) (Supplemental Table 2). Postoperative morbidity occurred at a rate of 9.3 %, and the mortality rate was 0% (Supplemental Table 3). The median follow-up was 10 months (range 8-13). No patient was lost during follow-up (Supplemental Table 4). Conclusion A laparoscopic subtotal gastrectomy with D2+CME procedure provides for a complete and standardized en bloc excision of the suprapancreatic area dissection.