Significance of prediction of the dorsal landmark using three-dimensional computed tomography during laparoscopic lymph node dissection along the proximal splenic artery in gastric cancer

OBJECTIVES: Dissection of the No. 11p lymph nodes is technically challenging because of variations in anatomical landmarks. This study aimed to determine the accuracy and efficacy of predicting the dorsal landmark of No. 11p lymph node using three-dimensional computed tomography simulation. METHODS: Laparoscopic gastrectomy with No. 11p lymph node dissection with preoperative simulation using three-dimensional computed tomography was performed in 24 patients at our institution from October 2016 to May 2018. Initially, preoperative three-dimensional computed tomography findings with operative videos in these 24 patients were compared. The dorsal landmark was defined as an anatomical structure behind the splenic artery on preoperative three-dimensional computed tomography and operative videos. The dorsal landmark of No. 11p lymph node was divided into four types: (1) splenic vein type, (2) splenic vein and pancreas type, (3) pancreas type, and (4) unclear type. Then, to investigate the efficacy of three-dimensional computed tomography, we compared the clinical and pathological features and surgical outcomes of nine patients who underwent preoperative three-dimensional computed tomography simulation (three-dimensional computed tomography group) and 23 patients who did not undergo three-dimensional computed tomography simulation from August 2014 to September 2016 (non-three-dimensional computed tomography group). All procedures were performed by one surgeon certified by the Endoscopic Surgical Skill Qualification System in Japan. RESULTS: The concordance rate between three-dimensional computed tomography and operative videos of the dorsal landmark using three-dimensional computed tomography was 79% (19/24). The operative time of No. 11p lymph node dissection was significantly shorter in the three-dimensional computed tomography group than in the non-three-dimensional computed tomography group (7.7 versus 15.8 min, P = 0.044). CONCLUSION: The accuracy of predicting the dorsal landmark of No. 11p lymph node using three-dimensional computed tomography was extremely high. Preoperative simulation with three-dimensional computed tomography was useful in shortening the operative time of No. 11p lymph node dissection.