Persistent Descending Mesocolon as a Risk Factor of Laparoscopic Surgery for Colorectal Cancer: A Single Institution Experience

The objectives of this study are to clarify the significance of persistent descending mesocolon (PDM), a kind of intestinal malrotation, in laparoscopic colorectal surgery and present potentially useful preoperative diagnostic methods for PDM. Although several risk factors for laparoscopic colorectal surgery have been convincingly reported, the impact of PDM on laparoscopic surgery for colorectal cancer remains less studied. This was an observational study with a retrospective analysis. A consecutive 110 patients undergoing laparoscopic colorectal surgery for colorectal cancer were included. To identify risk factors for operative time of laparoscopic surgery for colorectal cancer, we examined age, sex, body mass index, American Society of Anesthesiologists Performance Status score, tumor location, depth of tumor invasion, lymph node metastasis, and PDM as potential risk factors. For identification of appropriate preoperative diagnostic imaging, we reviewed three- dimensional vessel images reconstructed from computed tomographic slice data of all patients. During the study period, no effective pre- or intraoperative diagnoses of PDM were achieved. A total of 4 patients were diagnosed with PDM. Sex (P = 0.0032); tumor location (P = 0.0044); lymph node metastasis (P = 0.022); and PDM (P = 0.0007) were identified as risk factors based on multivariate analysis. A ventrally branched left colic artery visualized by three-dimensional imaging appeared to be a highly specific feature of PDM. Laparoscopic surgery for colorectal cancer with PDM was difficult without the recognition of PDM. PDM was well-defined preoperatively using three-dimensional vessels images reconstructed from computed tomographic slice data.