Transrectal Hybrid natural orifice translumenal endoscopic surgery sigmoidectomy has gained popularity. It is an appealing technique as a minilaparotomy in order to retrieve the specimen is avoided. Therefore less postoperative pain and a better cosmetic result are expected. The feasibility of the technique has been demonstrated.

Still an open question is the risk of intraperitoneal contamination as in this procedure the colon has to be opened. This is the case for (a) retrieval of the specimen thru the opened rectal stump and (b) for intracorporeal insertion of the anvil of the circular stapler in order to fashion an anastomosis.

In this study the bacterial contamination in the rectal stump as well as in the peritoneal cavity is assessed. The results are compared to bacteriological samples taken in a comparison group consisting of conventional laparoscopic assisted sigmoidectomies.

Inclusion Criteria:

• Status post several episodes of diverticulitis
• Status post contained diverticulitis

Exclusion Criteria:

• not able to give informed consent
• <18 years of age
• pregnancy
• emergency operation
• acute diverticulitis

Patients with an indication for elective sigmoidectomy for diverticular disease. Status post several episodes of diverticulitis, status post contained diverticulitis.