Initial introduction of robot-assisted, minimally invasive esophagectomy using the microanatomy-based concept in the upper mediastinum

Background: We have recently standardized upper mediastinal lymph node dissection (UMLND) using a microanatomy-based concept in thoracoscopic esophagectomy in the prone position (TEPP), and introduced robot-assisted minimally invasive esophagectomy (RAMIE) using the same concept as in TEPP while aiming at solo surgery. The purpose of this study was to investigate the outcomes of RAMIE using the microanatomy-based concept in the initial introduction phase. Methods: We have performed more than 500 TEPP procedures as minimally invasive esophagectomy (MIE). After performing about 400 cases of MIE, we established a microanatomy-based standardization of UMLND. In October 2018, we introduced RAMIE, and have performed 75 procedures in 20 months. Two groups were analyzed: a group after microanatomy-based standardization in TEPP (100 cases after completing 400 cases of TEPP) and a RAMIE group (75 cases). Finally, 51 paired cases were matched using a propensity score. Furthermore, the change in postoperative short-term outcome for RAMIE in the initial introduction phase was analyzed. Results: Although there were no significant differences between the two groups in the number of upper mediastinal lymph nodes dissected, there was a significant decrease (P = 0.036) in intraoperative blood loss volume with RAMIE, representing a definite benefit for patients. The thoracoscopic operative time for RAMIE decreased by almost 100 min following less than 50 cases of experience, reaching the same level as that for recent TEPP, but with only one-tenth the operator experience. There were no significant differences in the total postoperative morbidity rate including the recurrent laryngeal nerve palsy rate. Conclusion: RAMIE has been introduced safely and smoothly using the microanatomy-based concept established in TEPP.