[Clinical anatomy study of superior mesenteric vessels and its branches]

Objective: To examine the anatomical relationships of tributaries to superior mesenteric artery and vein in surgical procedures. Methods: A prospectively designed observational trial, registried to Chinese Clinical Trial Registry, ChiCTR 1800014610, was conducted in Department of General Surgery, Peking Union Medical College Hospital from July 2016 to Decmeber 2018 to record the relationships of ileocolic artery and vein, right colic artery and vein, middle colic artery and vein, and combinations to assemble Henle's trunk, during the laparoscopic operation of radical right colectomy for right colon malignancies. The length of middle colic artery, length of Henle's trunk, and distance from Henle's trunk to the inferior margin of pancreatic head to duodenum were measured during operation. A total of 100 patients, 52 male and 48 female, with right colon cancer, who underwent radical right colectomy, were enrolled in present study from July 2016 to December 2018, with age of (61.0±12.3) years (range: 31 to 82 years), and body mass index of (23.3±3.5) kg/m(2) (range: 16.0 to 34.2 kg/m(2)). Results: The ileocolic artery and vein presented as rates of 97.0% (97/100, 95%CI: 91.5% to 99.4%, the same below) and 98.0% (98/100, 93.0% to 99.8%), respectively. The ileocolic vein ran ventrally in 51 of 97 patients (52.6%, 42.7% to 62.5%). The right colic artery, which raised from superior mesenteric artery directly, was found in 42 of 100 patients (42.0%, 32.3% to 51.7%); and the right colic vein drained directly into superior mesenteric vein in 19 of 100 patients (19.0%, 11.3% to 26.7%). The presence of middle colic artery and vein were 95.0% (95/100, 90.7% to 99.3%) and 90.0% (90/100, 84.1% to 95.9%) respectively. The average length of middle colic artery, from its origin to bifurcation into right and left branches, was (2.6±1.6) cm (range: 0.1 to 7.2 cm). All the dissected middle colic vein drained into superior mesenteric vein (87.8% (79/90), 81.0% to 94.6%) and Henle's trunk (12.2% (11/90), 5.4% to 19.0%). Henle's trunk was found in 93 of 100 patients (93.0%, 88.0% to 98.0%), with average length of (1.0±0.6) cm (range: 0.1 to 2.4 cm). The distance between Henle's trunk to the inferior margin of pancreatic head was (2.7±0.7) cm (range: 1.3 to 4.5 cm). More than half of the Henle's trunk were composed of 3 tributaries (54.8% (53/93), 40.8% to 61.2%). The most frequently discovered tributaries to form Henle's trunk were right gastroepiploic vein (98.0% (98/100), 93.0% to 99.8%), superior right colic vein (82.0% (82/100), 74.5% to 89.5%), and superior anterior pancreaticoduodenal vein (78.0% (78/100), 69.9% to 86.1%). In present study, the right branch of middle colic vessels was often found to run closely with Henle's trunk, veins drained from small intestine could be found to run over superior mesenteric artery to converge into superior mesenteric vein. There were 2 incidences, injuries to Henle's trunk and middle colic vein, happened during the operation, which were overcomed by bipolar coagulation and dividing the vessels. Conclusions: Ileocolic vessels and middle colic vessels could be used as landmarks for laparoscopic surgery based on their constant anatomical existence. In contrast, the chances are rare for the presence of right colic artery or right colic vein. Nearly half of the Henle's trunk was consisted of right gastroepiploic vein, superior right colic vein and superior anterior pancreaticoduodenal vein. Exceptional cautions should be made for the variations of the Henle's trunk during the operation.