Natural orifice transluminal endoscopic surgery (NOTES) in the mediastinum: long-term survival animal experiments in transesophageal access, including minor surgical procedures.

BACKGROUND AND STUDY AIMS: Natural orifice transluminal endoscopic surgery (NOTES) within the peritoneal cavity is rapidly evolving, using transgastric, transcolonic, or transvaginal access. There is little experience with transesophageal NOTES access to the mediastinum. This prospective long-term animal survival study was performed to explore the feasibility and safety of transesophageal intrathoracic procedures including minor surgery.
MATERIAL AND METHODS: Nine pigs were used for acute (n = 2) and up to 6-week survival studies (n = 7), followed by autopsy and histological investigation. The esophageal incision site was chosen using EUS; this was followed by endoscopic mediastinoscopy and therapeutic procedures such as mediastinal lymph node removal, saline injection into myocardium, and pericardial fenestration. The wall was closed using a suturing system or endoscopic clips.
RESULTS: No acute complications were recorded with respect to mediastinal structures, pericardium, cardiac rhythm, or circulatory parameters. Removal of small mediastinal lymph nodes (n = 2) was feasible, but proved to be difficult. Other procedures, specifically at the heart were all successfully performed. Endoscopy after 4 - 6 weeks showed a well-healed esophageal incision. Autopsy with histology revealed no signs of mediastinitis, infection, bleeding, or pericarditis. The esophageal scar was found to be well healed in all cases, but with a muscular gap where clip closure had been used.
CONCLUSIONS: Transmural esophageal incision and endoscopic partial mediastinoscopy including therapeutic procedures on the heart or mediastinum proved feasible in long-term survival animal studies. Clip closure of the defect was effective, but did not close the esophageal muscle layer. Other means such as endoscopic suturing appear to be preferable.