Why The Proximal Splenic Artery Approach Is The Ideal Approach For Laparoscopic Suprapancreatic Lymph Node Dissection In Advanced Gastric Cancer?

Background: Laparoscopic gastrectomy with D2 lymph node(LN) dissection has not yet been widely adopted for advanced gastric cancer because it is technically complicated. Due to the high suprapancreatic lymph nodes metastasis rate(LMR) and the various vascular anatomies, the suprapancreatic LN dissection is a crucial and demanding procedure for laparoscopic radical resection of gastric cancer. Purpose: To explore the anatomical basis of the proximal splenic artery(SA) approach for laparoscopic suprapancreatic LN dissection and its application in advanced gastric cancer. Methods: Laparoscopic suprapancreatic LN dissections were performed in 1551 consecutive advanced gastric cancer patients between June 2007 and November 2013. The information on perigastric vascular anatomy [the proximal SA, common hepatic artery(CHA), left gastric artery(LGA), right gastric artery(RGA), and gastroduodenal artery(GDA)] and characteristics of suprapancreatic LN metastasis(No. 11 p,9,7,8a,5,12 a LNs) were prospectively collected and retrospectively analyzed. For suprapancreatic LN dissection, conventional approach was adopted from 2007 to 2011 and the proximal SA approach is used routinely since 2012. To exclude the influence of the learning curve on the surgical outcomes, a total of 994 consecutive patients since January 2011 were selected to compare the clinicopathological characteristics and surgical outcomes between the conventional approach group(330) and the proximal SA approach group(664). In the proximal SA approach, the No. 11 p LNs are dissected first, followed by the No. 9, 7 and 8a LNs; dissection of the No. 5 and 12 a LNs is performed last. Results: Suprapancreatic arteries associated with suprapancreatic LN dissection are mainly the proximal SA, CHA, LGA, RGA, and GDA. In the suprapancreatic arteries, the proximal SA had the lowest anatomic variation rate(P < 0.05, each) and maximum diameter(P < 0.05, each) compared with the CHA, LGA, RGA, and GDA. In addition, the proximal SA was located closer to the suprapancreatic border than the CHA(P = 0.000). The LMR of the suprapancreatic LNs was 51.8%(804/1551), and the No. 11 p LMR was lower than the No. 9, No. 7, No. 8a, No. 5 and No. 12 a LMR(P < 0.05, each). The mean operation time was similar between the two groups(P > 0.05). Compared with the conventional approach, the proximal SA approach was associated with less blood loss(P < 0.05), significantly more retrieved total LNs and suprapancreatic LNs(P < 0.01, each). Conclusions: The proximal SA exhibits the most constant and maximum diameter, is located closer to the suprapancreatic border and exhibits the lowest LMR; therefore, the proximal SA approach is the ideal approach for laparoscopic suprapancreatic LN dissection in advanced gastric cancer.