Chimney trial is designed to compare the effectiveness and safety of specifically designated polyvinylidene fluoride mesh (PVDF, Dynamesh IPST) to controls in a multi center, randomized setting.

The European Hernia Society recommends the use of prophylactic mesh when permanent colostomy is made. The results of previous trials using keyhole technique are partially unsatisfactory. Specifically designed PVDF mesh used in this trial showed promising results in previous small trial.

Chimney trial is designed to compare the effectiveness and safety of mesh group to controls operated with no preventive mesh in parastomal hernia prevention after laparoscopic or robotic-assisted abdominoperineal resection or low Haartman's procedure for rectal adenocarcinoma.

Inclusion Criteria:

• 18 years or older
• Rectal adenocarcinoma with curative intent laparoscopic or robotic assisted abdominoperineal resection or low Hartmann´s operation and permanent colostomy
• Patient has a life expectancy of at least 12 months.
• Patient must sign Informed consent before any study procedures and agrees to attend all study visits

Exclusion Criteria:

• Abdominoperineal resection or Hartmann's operation by laparotomy or conversion to laparotomy
• Complication requiring laparotomy during post surgery treatment at surgical ward after APR
• Patient with a comorbid illness or condition that would preclude the use of surgery (ASA 4-5).
• Patients with concurrent or previous malignant tumors within 5 years before study enrollment
• Patients with T4b tumors which impose a multi-organ resection
• Rectal malignancy other than adenocarcinoma
• Patient undergoing emergency procedures
• Planned rectal surgery along with major concomitant procedures (e.g. hepatectomies, other intestinal resections).
• Metastatic disease with no possibility of curative surgery
• Pregnant or suspected pregnancy
• Patients living geographically distant and/or unwilling to return for follow-ups or comply with all study requirements
• Active abdominal infection at the time of surgery
• Previous surgery at the colostomy site
• Language barrier or other reasons why informed consent is not possible

Participants are unaware of the randomization group.