Comparative study of NOTES alone vs. NOTES guided by a new image registration system for navigation in the mediastinum: A study in a porcine model

Background and study aims: Natural Orifice Transluminal Endoscopic Surgery (NOTES) mediastinoscopy through the esophagus has proven to be feasible in the animal model. However, injury of the adjacent pleura and pneumothorax has been reported as a frequent complication when using a blind access. The aim of the current study was to assess the utility and safety of a CT-based Image Registered (IR) navigation system to identify mediastinal structures.

Methods and Procedures: 30-minute media? stinoscopies were performed in 30 pigs: 15 procedures used IR guidance (IR-MED) and 15 procedures used a blind access (MED). In both groups, the mediastinum was accessed through a 10cm-submucosal tunnel in the esophageal wall. Timed exploration was performed with identification of 8 organs (carina, right pulmonary artery, right atrium, cava vein, porcine bronchium, brachiocephalic vein, right vagus nerve and lung). Necropsy was immediately performed after the procedure.

Results: 30 animals weighting 31.5 ± 3.5 kg were included in this study. Mediastinoscopy was not possible in two animals in MED group but in all in IR-MED. The mean number of identified organs was slightly higher in IR-MED (6.13 ± 1.3) than in MED (4.7 ± 2.3; p ((equals)) 0.066). Moreover, right atrium and cava vein were identified in more cases in IR-MED than in MED (13 vs. 3 and 15 vs. 11, p ((equals)) 0.000 and 0.03, respectively). We had 3 (23%) complications in IR-MED vs. 4 (27%) in MED (p ((equals)) ns) being pneumothorax the most frequent (2 and 3, respectively).

Conclusion: The present study demonstrates that IR system appears feasible in NOTES mediastinoscopy and suggests that IR guidance might be useful for selected procedures.