Study is a prospective, multicenter, randomized trial evaluating whether prophylactic laparoscopic placement of a dual-component IPOM mesh around a colostomy may prevent parastomal hernia compared with conventional colostomy after abdominoperineal resection. Eligible subjects will be recruited prospectively from five Finnish Hospitals (Oulu University Hospital,Vaasa Central Hospital, Helsinki University Hospital, Lahti Central Hospital, Jyväskylä Central Hospital). Patients were considered eligible for this study if undergoing laparoscopic abdominoperineal resection for rectal adenocarcinoma. Patients are randomized to prophylactic preperitoneal placement of a dual-component mesh (Dynamesh IPOM) around permanent colostomy or to conventional permanent colostomy. Estimating a parastomal hernia rate of 50%, a sample size of 26 patients per each study group is projected to provide 90% power (1-beta) with a alpha 0.05 (2-beta) to detect a 40% reduction in risk for parastomal hernia at 1-year. Since we expect a dropout rate of 20%, 37 patients per study group will be included in this study.

All abdominoperineal resections are performed using laparosopic technique. At the and of the abdominal laparoscopic phase the straight permanent end colostomy is performed. In the intervention group the 10 x 10 cm Dynamesh IPOM mesh is cut in the middle according to volume of the bowel. Stapled bowel end is then pulled through the crosswise opened mesh, which is pushed to the abdomen and fixed to the peritoneum.

Follow-up visits are scheduled at 1-, 3- and 12-month after surgery. Patients are evaluated for their clinical status and C-reactive protein, leukocytes and hemoglobin are assessed at each control visit. Computed tomography (CT) scan with and without Valsalva maneuver is performed 12 months after surgery for radiological evaluation of possible parastomal hernia.

The primary end-point of this study is the incidence of clinically and radiologically detected parastomal hernias, and their extent 12 months after surgery. The secondary outcome end-points were colostomy-related morbidity such as stomal stenosis, necrosis and/or wound infection.The extent of parastomal hernia was graded at CT according to the Hernia Society criteria.

Statistical analysis is performed using a SPSS statistical software. Continuous variables are reported as the mean and standard deviation, whereas nominal variables are reported as counts and proportions. Univariate analysis is performed with the Mann-Whitney U test and Fisher's exact test. P-values < 0.05 are considered statistically significant.

Inclusion Criteria:

• Patients undergoing laparoscopic abdominoperineal resection for rectal adenocarsinoma

Exclusion Criteria:

• Patients who can not give their consent to participate in the study
• Patients in poor general conditions (American Society of Anaesthesiologists classes 4-5)
• Patients with incurable cancer or another rectal malignancy than adenocarcinoma
• Patients with any abdominal infection