Microanatomy-based standardization of left upper mediastinal lymph node dissection in thoracoscopic esophagectomy in the prone position

Background: Although thoracoscopic esophagectomy in the prone position (TEPP) has become a standard procedure for esophageal cancer surgery, upper mediastinal lymph node dissection (UMLND) on the left side remains an issue. We have recently developed a new standardized approach to left UMLND in TEPP based on the microanatomy of the membranes and layers with the aim of achieving quick and safe surgery. The purpose of this study was to establish and evaluate our new standardized procedure in left UMLND. Patients and methods: Patients were divided into 2 groups: a pre-standardization group (n = 100) and a post-standardization group (n = 100). Eventually, 83 paired cases were matched using propensity score matching. In our new standardized procedure, left UMLND was performed while focusing on the visceral sheath, vascular sheath, and the fusion layer between them using a magnified view. Results: The thoracoscopic operative time was significantly shorter (P < 0.001) in the post-standardization group [n = 83; 209.0 (176.0–235.0) min] than in the pre-standardization group [n = 83; 235.5 (202.8–264.5) min]. No significant differences were found in the number of mediastinal lymph nodes dissected or intraoperative blood loss between the two groups. There was a tendency for the total postoperative morbidity to decrease in the post-standardization group. Furthermore, the left recurrent laryngeal nerve palsy rate was significantly lower in the post-standardization group (18.1% to 8.7%, P = 0.015). Conclusion: Microanatomy-based standardization contributes to safe and efficient left UMLND.