Natural orifice transluminal endoscopic surgery has become an important topic. NOTES access routes give the opportunity to reduce surgical access trauma leading to a more painless surgery and enhancing a fast postoperative recovery. Experience with transvaginal laparoscopic cholecystectomy and transvaginal anterior resection for diverticulitis show that such NOTES procedures are feasible and safe. The complication rate to conventional laparoscopic procedures is similar. Since transvaginal access is impossible in men, an alternative route is missing. There are experimental studies and small case series reporting the feasibility of transrectal anterior resection. However any prospective feasibility study demonstrating the safety of the procedure and functional outcomes (sphincter function) are missing. This study investigates the feasibility, practicability, safety and subjective as well as functional outcome of transrectal hybrid-NOTES anterior resection.

Primary endpoint:

To demonstrate in a prospective cohort study the feasibility (specimen extraction through rectum possible to perform or not), safety (complications graded according to Clavien-Dindo) and postoperative outcome (gastrointestinal quality of life questionnaire and anal sphincter manometry) of routine hybrid-NOTES transrectal anterior resection for benign indication in men and women.

Secondary endpoints:

• quality of life 6 months after surgery
• continence 6 months after surgery
• pain postoperative
• complication rate
• duration of procedure
• lengh of stay

Hypothesis:

The investigators expect specimen extraction through the rectum to be feasible in 80% of cases (in the others an alternative mini-laparotomy has to be performed).

study design: This is an open cohort study on 60 patients. The patients are included before surgery and baseline parameters are put in a registry. There are clinical controls 6 weeks, 3 and 6 months postoperative. 3 and 6 months postoperative as well as preoperative a anorectal manometry is performed.

Inclusion criteria:

- benign indication for left sided colectomy.

exclusion criteria:

• age <18 years
• patient unable to understand informed consent or missing informed consent
• emergency surgery

power calculation: A feasibility of 80% with a precision of 15% is estimated. Given a 5% drop out rate 36 patients are to be included in the study.

Inclusion Criteria:

• benign indication for left sided colectomy

Exclusion Criteria:

• age below 18 years
• unable to understand informed consent of missing informed consent
• emergency surgery

Patients with benign indication for left sided colectomy