Notes Thoracic Surgery In A Human Cadaveric Model: Transesophageal Exploration Of The Mediastinal, Pericardial And Pleural Spaces Followed By Pleural Biopsy, Lymph Node Sampling, Thoracic Duct Ligation, Vagotomy, Thymectomy And Pericardial Window

Background: Transesophageal access to the mediastinum and thorax carries the potential for the elimination of painful incisions, wound infections and other complications related to thoracoscopy and thoracotomy. Investigation of the transesophageal route has thus far been limited to porcine studies. Aim: To perform a systematic transesophageal exploration of the human mediastinum and thorax, and to assess the feasibility of advanced NOTES surgery in these compartments. Methods: Two human cadavers (1 male, 1 female) were utilized with video logs maintained throughout the study. A prototype double-channel endoscope (Olympus R-Scope) and the Erbe Hybrid knife, which combines a tissue-selective water jet and cautery, were used as the endosurgical platform. A posterior submucosal flap extending from 25 cm to 35 cm from the incisors was created. Transesophageal access to the thorax was obtained at 30 cm. The mediastinal, pleural and pericardial compartments were systematically explored. The trachea, mediastinal lymph nodes, azygos vein, thymus, pericardium, lung, pleura, diaphragm, vagus nerve and thoracic duct were identified. A right thoracotomy was performed to facilitate orientation, exposure and confirmation of anatomic structures. Subsequently, advanced NOTES procedures were performed. Pleural biopsies were obtained. Mediastinal and hilar lymph nodes were resected with hydrodissection and biopsy forceps. The thoracic duct was ligated using endoscopic clips. A vagotomy was performed using clips after cautery dissection. A pericardial effusion was simulated and a 3×3 cm pericardial window was created with drainage of fluid. The pericardial space was explored and the epicardium visualized. Thymic tissue and its fat pad were resected from the edge of the pericardial window toward the internal mammary artery. Results: Esophageal submucosal flap creation by hydrodissection was technically feasible. Complete exploration of the posterior mediastinum, pleural space and pericardial cavity was possible via transesophageal access. Lymph node sampling, pleural biopsy, vagotomy, thoracic duct ligation, pericardial window and thymectomy were successfully performed. Conclusion: NOTES thoracic surgery via transesophageal access is technically feasible in the human cadaver model. Exploration and complex endosurgical procedures were possible using this prototype platform and dissection equipment. Translation to living patients will be challenging and will likely require a sterile conduit, novel tissue closure technique, endoscopic ultrasound for anatomic mapping, and specialized ventilatory strategies.