Factors affecting the quality of laparoscopic D2 lymph node dissection for gastric cancer: a cohort study from two randomized controlled trials.

Background: Laparoscopic D2 lymph node dissection (LND) for gastric cancer has a wide range and high difficulty. In the past, the quality of surgery was often judged by the time of the operation or the amount of blood loss, but the analysis based on surgical video was rarely reported. The purpose of this study was to analyze the relationship between the quality of laparoscopic D2 LND for gastric cancer and postoperative complications.

Methods: The surgical video and clinicopathological data of 610 patients in two randomized controlled trials in our center from 2013 to 2016 were retrospectively analyzed. Klass-02-QC LND scale and general error score tool were used to quantitatively evaluate the intraoperative performance of D2 LND. Logistic regression was used to analyze the influencing factors of postoperative complications.

Results: The overall incidence of complications (CD classification≥2) was 20.6%; the incidence of surgical complications was 6.9%. According to whether the LND score reached 44, patients were divided into a qualified group (73%) and a not-qualified group (27%). Event score (ES) by quartile was divided into grade 1 (21.7%), grade 2 (26%), grade 3 (28%), and grade 4 (24.3%) from low to high. Univariate logistic regression analysis showed that ES greater than or equal to 3, tumor size greater than or equal to 35 mm, and cTNM >II were independent risk factors for not-qualified LND. Male,tumor size greater than or equal to 35 mm and cTNM >II were independent risk factors for grade 4 ES. Not-qualified LND (OR=1.62, 95% CI: 1.16-3.89, P =0.021), grade 4 ES (OR=3.21, 95% CI: 1.52-3.90, P =0.035), and cTNM >II (OR=1.74, 95% CI: 1.39-7.33, P =0.041) were independent risk factors for postoperative surgical complications.

Conclusions: The qualification of LND and intraoperative events based on surgical video are the independent influencing factors of postoperative complications of laparoscopic gastric cancer surgery. Specialist training and teaching based on surgical video may help to improve the surgical skills of specialists and improve the postoperative outcome of patients.