Perirectal Oncologic Gateway to Retroperitoneal Endoscopic Single-Site Surgery (PROGRESSS): a feasibility study for a new NOTES approach in a swine model.

Introduction: A transanal, posterior, retrorectal approach has been demonstrated as a feasible natural orifice transluminal endoscopic surgery (NOTES) total mesorectal excision (TME) procedure. The aim was to assess the feasibility of a transrectal approach with a completely retroperitoneal mobilization of the left colon and mesenteric vessels in an acute porcine model.

Materials And Methods: Eight pigs were used. A purse-string suture was made 3 cm above the anal sphincter. Next, the retroperitoneal, perirectal space was entered with an endoscope through a single (or twin) anterior lateral, transrectal viscerotomy. A retroperitoneal tunnel was created using pneumodissection or endoscopically guided dissection to the inferior mesenteric artery (IMA). The IMA was skeletonized and lymph nodes retrieved using the IsisScope or other instruments. The IMA was divided with the Ligasure, clips, or ligature performed with the IsisScope. The rectum was dissected transanally in the "Holy" plane. After achieving mobilization using a completely retroperitoneal approach, the peritoneal attachments were then divided and the rectosigmoid specimen exteriorized through the anus. An explorative laparoscopy was then performed to evaluate the quality of the mobilization.

Results: The procedure was successfully completed and the IMA correctly identified and ligated in all cases. In all but one case, no further mobilization was possible, even by a laparoscopic approach.

Conclusions: Perirectal oncologic gateway to retroperitoneal endoscopic single-site surgery for left-sided colonic resections using both flexible and rigid surgical endoscopic platforms was feasible and reproducible in an acute porcine model. This technique might represent a step toward pure NOTES left-sided colorectal procedures.