Standardization of bilateral upper mediastinal lymph node dissection using microanatomical concepts in minimally invasive esophagectomy

Abstract

Aim:We have recently standardized upper mediastinal lymph node dissection (UMLND) based on microanatomical concepts in minimally invasive esophagectomy using a 4K ultra-high-definition (HD) system. In this study, the aim was to investigate the outcomes of microanatomy-based standardization using 4K ultra-HD for UMLND with the main focus on thoracoscopic operative time. Methods:We have performed more than 500 cases of thoracoscopic esophagectomy in the prone position as minimally invasive esophagectomy. After about 400 cases of thoracoscopic esophagectomy in the prone position, we established the microanatomy-based standardization of UMLND using a 4K ultra-HD system. Two groups were analyzed: a pre-standardization group (n = 100) and a post-standardization group (n = 100). Furthermore, the change in our thoracoscopic operative time for all cases was analyzed using the moving average method.Results: In the post-standardization group, the rate of surgeries performed by operators with less than 20 years' experience was significantly higher (P < 0.001). There were no significant differences in the number of mediastinal lymph nodes dissected, intraoperative blood loss and total postoperative morbidity rates between the two groups. The rate of recurrent laryngeal nerve palsy decreased to less than half (19.8% to 9.6%) (P = 0.061) and the thoracoscopic operative time decreased [232.0 (202.8-264.0) min to 209.0 (176.0-235.0) min] significantly (P < 0.001) after standardization. The moving average showed a marked decrease of thoracoscopic operative time during the standardization phase. Conclusion:Microanatomy-based standardization enabled quicker and more precise UMLD despite an increase in the number of surgeries performed by less experienced operators.