Collateral thermal damage to the pancreas by ultrasonic instruments during lymph node dissection in laparoscopic gastrectomy

Introduction: Laparoscopic gastrectomy (LG) with D2 or more extended lymphadenectomy for advanced gastric cancer is technically demanding. Collateral thermal damage to the pancreas secondary to energized dissection during lymphadenectomy has been reported. We retrospectively compared the pancreatic damage between LG and open gastrectomy (OG) by measuring the amylase concentration of the drainage fluid and analyzing heat conductance to the pancreas with a porcine model. Methods: We evaluated the data of 105 consecutive patients with gastric adenocarcinoma who underwent LG or OG with lymph node dissection. Digital thermography was used to evaluate the extent of heat conductance to the pancreas during suprapancreatic lymph node dissection by either an ultrasonically activated device or electric cautery in a porcine model. Results: The incidence of clinically relevant pancreatic fistula formation was not statistically significant between the LG and OG groups (3/57 vs 0/48 cases; P = 0.306). However, the median amylase concentrations of the drainage fluid on postoperative days 1 and 3 were 1355.7 and 308.8 IU/L, respectively, in the LG group and 369.0 and 125.8 IU/L, respectively, in the OG group (P < 0.001). In the experimental model, more time was required to cool the surface of the pancreas to < 40 degrees C in the ultrasonically activated device group than in the electric cautery group (10.1 +/- 5.2 vs 5.2 +/- 3.0 s; P = 0.013). Conclusions: Unavoidable collateral thermal damage to the pancreas associated with electrosurgical devices might exist during LG. Heat conductance must be given more consideration in extended lymph node dissection.