[Comparison of clinical efficacy between bursa omentalis approach and medial-to-lateral approach in laparoscopic left hemicolectomy: a propensity score matching analysis].

Splenic flexure mobilization is technically difficult during the resection of left hemicolon cancer. This study aims to compare the safety and effectiveness between the bursa omentalis approach (BOA) and medial-to-lateral approach (MTLA) in laparoscopic radical resection of left-sided colon cancer. A retrospective cohort study was conducted. Inclusion criteria: (1) patients underwent radical resection of left hemicolon cancer; (2) the postoperative pathological result was adenocarcinoma; (3) patients aged 18-80 years old; (4) no liver, peritoneal or other distant metastasis. Exclusion criteria: (1) poor physical condition with serious heart, brain, lung, liver, kidney and hematopoietic system diseases; (2) unable to tolerate laparoscopic surgery; (3) history of other malignancies simultaneously, or multisource tumors; (4) emergency operation due to bleeding, obstruction, perforation, etc. Clinical data of 189 patients who underwent laparoscopic left hemicolectomy in the Guangdong Provincial Hospital of Chinese Medicine from 2014 to 2020 were retrospectively analyzed. According to surgical approaches, patients were divided into the BOA group (52 cases) and MTLA group (137 cases). The whole group of patients were matched by propensity score matching (PSM) according to the nearest neighbor matching method. The caliper value was 0.01. The matching variables included gender, age, American Society of Anesthesiologists (ASA) score, body mass index, tumor location and tumor stage. After PSM, 47 patients were included in the BOA group and MTLA group, respectively. There were no significant differences in baseline data between the two groups after PSM (all >0.05). Paired -test, paired rank sum test and paired Chi-square test were used to compare intraoperative and postoperative paramether between the two groups. Kaplan-Meier method was used to draw the survival curve, and log rank test was used for inter group comparison. When the two survival curves intersect, the two-stage method and restricted mean survival time (RMST) were further performed. Both groups of patients successfully completed the operation without conversion to laparotomy or intraoperative death. No combined splenectomy or pancreatectomy were performed in the two groups. There were also no significant differences in intraoperative blood loss, number of harvested lymph nodes, time to the first flatus and the length of hospital stay between the two groups (all >0.05). However, the median laparoscopic dissection time in the BOA group was shorter than that in the MTLA group, and the difference was statistically significant (median: 56 minutes vs. 65 minutes, =0.032). No entry to posterior pancreatic space was recorded in the BOA group but wrong entry to posterior pancreatic space happened to 6.4% (3/47) of patients (body mass index >25 kg/m(2)) when dissecting left Toldt's fascia in the MTLA group. The 3-year disease-free survival rate in BOA group and MTLA group was 90.2% and 86.1%, respectively (=0.909) and the 3-year overall survival rate was 85.6% and 94.4%, respectively (=0.532). BOA is safe and feasible in laparoscopic left hemicolectomy, especially for inexperienced surgeons. For obese patients, BOA facilitates the entrance into the correct anatomical level and avoid entering the retropancreatic space.