196. MINIMALLY INVASIVE ESOPHAGECTOMY WITH AWARENESS OF THE THIN MEMBRANOUS DENSE CONNECTIVE TISSUES AROUND THE ESOPHAGUS

Abstract

Abstract Background We have clinically introduced the ‘mediastinoscopic esophagectomy with lymph node dissection’ (MELD) to esophagectomy for thoracic esophageal cancer, performed under pneumomediastinum via trans-bicervical and transhiatal approach since 2014. In parallel with this, we have been conducting histological studies of the thin membranous dense connective tissue (TMDCT) around the esophagus and utilizing the results during these surgeries to ensure a rational esophagectomy. Here, we describe the differences in the visibility of TMDCT between the two approaches for esophagectomy. Methods We retrospectively examined the visibility of TMDCT in surgical videos of trans-mediastinnal and trans-right thoracic approaches after 2015 to determine the characteristics of each approaches. Results The trans-mediastinal approach reaches the visceral sheath by entering just dorsal to the esophagus in the right neck, and the TMDCT is seen in a bubbled appearance. Unlike the right thoracic approach, the visceral sheath can be easily reached without a pleural incision. The adipose tissue including lymph nodes around the left recurrent laryngeal nerve (RLN) showed a clear dissection layer between the left subclavian artery, but the boundary between the lymph nodes around the left RLN and the aorta was unclear near the aortic arch, which was thought to be due to the lack of visceral sheath around No.106tbL. On the other hand, the trans-right thoracic approach showed a slightly shiny visceral sheath covering the surface of the thoracic duct on the dorsal side of the esophagus. In the left superior mediastinum, the left RLN and RLN lymph nodes were located on the organ side of the visceral sheath covering the esophagus and trachea. In right and left sides, the visceral sheath was obscured near the branch of the RLN from the vagus nerve, but the RLNs ran cranially on the medial side of the visceral sheaths. Conclusion We reported how the TMDCT is visualized with each surgical approach. The visceral sheath was visualized as a bubbly structure in the trans- mediastinal approach and as a slightly shiny areal structure in the trans-right thoracic approach. Recognition of the TMDCT around the esophagus was useful for safe and rational lymph nodes dissection regardless of the surgical approach.