Lymphatic mapping and sentinel node biopsy in the colonic mesentery by Natural Orifice Transluminal Endoscopic Surgery (NOTES).

INTRODUCTION: Although intraluminal and transluminal techniques can achieve localized resection of early-stage alimentary tumours, they do not designate the status of the filtering mesenteric lymph nodes. Natural orifice transluminal endoscopic surgery (NOTES) may however effect sentinel node biopsy from within the peritoneum.
METHODS: A transgastric NOTES technique was utilized in six pigs. A conventional double-channel gastroscope created both the 12mm anterior gastrotomy and the pneumoperitoneum and enabled peritoneoscopy. The sigmoid colon was fully exposed by an intracolonic magnet under extracorporeal control. Colonoscopy facilitated submucosal injection of methylene blue dye (3 ml) at the apex of the sigmoid loop under direct transgastric vision. The mesocolon was searched for blue-stained lymph channels and nodes, the latter being resected and retrieved by the intraperitoneal endoscope. At procedure end, three pigs underwent immediate laparotomy for scrutiny of the operation site while three were survived for forensic laparotomy on postoperative day 14.
RESULTS: Each procedure was a technical success. Gastrotomy, pneumoperitoneum, peritoneoscopy and sigmoid exposure were promptly achieved (mean 9.2 min). Post-injection, blue lymphatics identifying specific nodes were immediately appreciable and these could be dissected cleanly and retrieved intact per oram. Mean lymphadenectomy time was 19 (range 12-32) min. All survival animals thrived during convalescence. At laparotomy, there was neither mesentery penetration, bowel ischemia nor mesenteric hematoma/hemorrhage in any pig and no residual blue stained nodes in those sacrificed early.
CONCLUSION: Sentinel node biopsy can be performed without abdominal wall transgression. Thus potentially the oncological proprietary of local resectional techniques may be augmented while preserving their ideals and dividends.