Natural Orifice Transesophageal Mediastinoscopy and Thoracoscopy: A Survival Series in Swine

Introduction: Mediastinoscopy (MX) and thoracoscopy (TX) are common procedures with painful incisions and prominent scars. A natural orifice transesophageal endoscopic surgery (NOTES) approach could reduce pain, eliminate intercostal neuralgia, provide access to the posterior mediastinal compartment or hilum, and improve cosmesis. The purpose of this study is to create a survival animal model for NOTES MX and TX.
Methods: Phase 1: nonsurvival study of NOTES MX and TX in 5 swine. Using cap endoscopic mucosal resection and blunt dissection, a 10 cm submucosal tunnel was created in the esophagus. The endoscope was passed through the tunnel and out into the mediastinum. The mediastinal compartment, pleura, lung, and esophagus were identified. A small incision was then made in the pleura and the thoracic cavity was explored. The lung, chest wall, and diaphragmatic surface were identified and pleural biopsies were obtained. Phase 2: 8-day survival study in 4 swine using the same technique. One swine underwent MX only and 3 swine underwent MX and TX. Esophageal closure was obtained via submucosal tunnel flap-valve alone (2 swine) or reinforcement with mucosal clips (2 swine). The mediastinal and thoracic cavities were examined at necropsy and resected esophageal specimens were sent for pathological examination.
Results: In all animals, mediastinal and thoracic structures were identified without difficulty and pleural biopsy was easily achieved. In one nonsurvival animal, an inadvertent lung injury caused a pneumothorax which was decompressed through a small intercostal incision. All Phase 2 animals survived for 8 days, thrived, and gained weight. At necropsy, some bruising of the lung was noted in each animal. There was no evidence of free esophageal perforation or mediastinitis. One animal (mucosal clip closure) developed a contained fluid collection in the submucosal esophageal tunnel.
Conclusions: Transesophageal endoscopic mediastinoscopy and thoracoscopy provide excellent visualization of mediastinal and intrathoracic structures. Pleural biopsy can be easily obtained under direct visualization. The submucosal tunnel creates a flap-valve that, alone, may be sufficient for preventing esophageal leak. These procedures can be performed safely in swine with short-term survival and no evidence of clinical deterioration. However, procedural morbidity needs to be minimized and further study with a larger sample size and longer survival is warranted.

Session: Podium Presentation

Program Number: S037