Study on anatomical classification of the superior anterior pancreaticoduodenal vein under the laparoscopic view        ZHANG Jun-ling*, Bianba Tashi, JIANG Yong, et al.*Peking University First Hospital, Department of General Surgery, Beijing 100034,China 
Corresponding author: JIANG Yong, E-mail: surgeonjiangy@sina.com
ZHANG Jun-ling and Bianba Tashi are the first authors who contributed equally to the article
Abstract    Objective    To summarize the anatomical classification and characteristics of the superior anterior pancreaticoduodenal vein (ASPDV) under the laparoscopic view, and to analyze their clinical significance. Methods    By reviewing recorded surgical videos and surgical records, the anatomical variations of ASPDV from 211 patients who underwent laparoscopic radical right hemicolectomy in Peking University First Hospital between January 2015 and June 2022 were retrospectively studied. Besides, the operation time and intraoperative blood loss were analyzed. Results Three types of ASPDV were classified according to the anatomical reflux site of ASPDV under the laparoscopic view: typeⅠ, in which ASPDVs were only draining into Henle trunk, as the most common type, accounting for 83.9%(177/211); typeⅡ, in which ASPDVs were only draining into the superior mesenteric vein (SMV), accounting for 11.4% (24/211); Type Ⅲ, in which ASPDVs were draining both into Henle trunk and SMV respectively, accounting for 4.7% (10/211). For typeⅠ, subtypes were defined according to the branch numbers of the ASPDVs: subtypeⅠa, with one ASPDV branch draining into Henle trunk, accounting for 72.5% (153/211); subtypeⅠb, with two ASPDV branches draining into Henle trunk, accounting for 9.0% (19/211); subtypeⅠc, with three or more ASPDV branches draining into Henle trunk, accounting for 2.4% (5/211). According to the confluence site of the ASPDV and Henle trunk, both of typeⅠand typeⅢ, in which ASPDVs were draining into Henle trunk involving 187 cases, were further subtyped into proximal convergence (95.2%, 178/187) and distal convergence (4.8%, 9/187). Compared with subtypeⅠa+ typeⅡpatients, subtypeⅠb+subtypeⅠc +typeⅢpatients had a longer operation time［(29.2±4.4) min vs.(21.6±5.6) min, t=7.5, P< 0.001］  and more intraoperative blood loss［25(20，50)mL vs.20(20，30)mL, U=2084, P=0.002］. In addition, compared with proximal convergence type patients, the distal convergence type patients had longer operation time ［(32.5±5.9)min vs. (22.4±5.8)min, t=4.8, P<0.001］ and more intraoperative blood loss ［50(20，50)mL vs. 20(20，30)mL, U=465, P=0.02］. Conclusion    Based on the different types of ASPDV under the laparoscopic view，typeⅠa and proximal convergence type are the most common type in the clinic. APSDV with multiple branches or distal convergence type had longer operation time and a higher risk of bleeding.