Impact of prior thoracoscopic experience on the learning curve of robotic McKeown esophagectomy: a multidimensional analysis

Purpose: Left upper mediastinal lymph node dissection (UMLND)—a technically demanding step of McKeown esophagectomy—is frequently complicated by recurrent laryngeal nerve (RLN) palsy. Under the hypothesis that robotic esophagectomy (RE) could increase the safety and feasibility of UMLND, we retrospectively investigated the degree to which a pre-existing experience in video-assisted thoracoscopic esophagectomy (VATE) may affect the learning curves of this critical part of RE. Methods: Surgeon A had previously performed > 150 VATE procedures before transitioning to RE. While surgeon B had previously assisted to 50 RE, his pre-existing VATE experience consisted of less than five procedures. A total of 103 and 76 McKeown RE procedures were performed by surgeons A and B, respectively. The learning curve of left UMLND for each surgeon was examined using the cumulative sum method. Results: The inflection point of RLN palsy for surgeon A occurred at patient 31. While the nerve palsy rate decreased from 32.3 to 4.2% (p < 0.001), the number of nodes harvested during left UMLND did not appreciably change. Surgeon B showed a bimodal learning curve for RLN palsy with primary and secondary inflection points at patients 15 and 49, respectively. The RLN palsy rate initially decreased from 66.7% (patients 1–15) to 14.7% (patients 16–49), followed by an additional decline to 3.7% (patients 50–76). However, the number of nodes harvested during left UMLND showed a downtrend which was paralleled by decreasing rates of RLN palsy. These results indicate that surgeon B has not yet reached an ideal balance between an extensive UMLND and nerve protection. Conclusion: The pre-existing VATE experience seems to affect the learning curves of left UMLND during RE.