A novel single-port technique for transanal rectosigmoid resection and colorectal anastomosis on an ex vivo experimental model

Background In the context of natural orifice translumenal endoscopic surgery (NOTES), we developed a new set of rigid instruments according to the principles of transanal endoscopic microsurgery (TEM).These instruments are long, curved, and steerable by rotating two wheels near its handle. Our success in transvaginal cholecystectomy in human with these instruments motivated us to explore the feasibility of rectosigmoid resection through the anus. Methods The young bovine large bowel with attached organs is collected en bloc and reintegrated into an anatomically designed trainer to reproduce the human anatomy. The technique comprises the following: (1) closure of the rectal lumen by an endolumenal pursestring suture; (2) transection of the rectal wall 1 cm distal to the pursestring suture and continuation of the dissection toward the fascia and upward excising the mesorectal tissue; (3) inferior mesenteric artery is divided near its origin; (4) the colon is mobilized up to the splenic flexure; (5) the mobilized colon is brought down to the pelvis, ligated twice at the intended proximal resection site, and divided between the ligatures; (6) specimen is delivered transanally; and (7) intestinal continuity is restored by stapled or hand-sutured anastomosis. Results Twelve rectosigmoid resections, 20 stapled, and 27 hand-sutured anastomoses were performed in two experimental setups. Mean operation time for the resection part was 78.6 min (standard deviation (SD) = 9.9). The average specimen length was 37.2 cm. During dissection in the pelvis, as the specimen was pushed upward and toward abdomen, an "empty pelvis" view of the working field was achieved, facilitating dissection. The mean operation time for hand-sutured and stapled anastomoses were 47.7 (SD = 6.9) and 43.3 (SD = 7.1) min, respectively. Both groups had one anastomotic leak. Conclusions Transanal rectosigmoid resection is feasible with TEM technology. The unobstructed "empty pelvis" view is likely to enhance the quality of mesorectal dissection.