Evaluation of the venous drainage pattern of the splenic flexure by preoperative three‐dimensional computed tomography

INTRODUCTION: Anatomical evaluation of the splenic flexure vein is essential for complete mesocolic excision with central vascular ligation when treating patients with splenic flexure cancer. Although there have been several studies relating to the arterial branches of the splenic flexure, very limited data are available regarding the variation in venous anatomy in this region. METHODS: Sixty-six patients with colorectal cancer who underwent preoperative 3-D CT between April 2016 and April 2017 were included in this retrospective study. The pattern of the venous drainage of the splenic flexure and its association with the inferior border of the pancreas were evaluated. RESULTS: The inferior mesenteric vein flowed into the splenic vein in 32 patients (48.5%), into the superior mesenteric vein in 27 patients (40.9%), and into the confluence of splenic vein and superior mesenteric vein in 7 patients (10.6%). The splenic flexure vein joined the inferior mesenteric vein in 62 patients (93.9%), the splenic vein in 2 patients (3.0%), and the middle colic vein in 2 patients (3.0%). The splenic flexure vein flowed into the inferior mesenteric vein below the level of the inferior border of the pancreas in 58 patients (90.6%) and above it in 4 patients (6.3%). CONCLUSION: Preoperative evaluation of the venous pattern of the splenic flexure on 3-D CT is useful before complete mesocolic excision with central vascular ligation to avoid intraoperative bleeding during splenic flexure cancer surgery.