The study will explore the ability of negative pressure wound therapy (Prevena dressing) to reduce post operative superficial surgical site infection rate in elective colorectal surgery. Half of the participants will receive Prevena dressing on closed incision immediately after the operation while other half will receive conventional surgical dressing.

The trial will commence with recruitment of participants after an assessment of their potential eligibility. Those recruited in the trial will sign informed consent either on the day of surgery or during the PAC appointment, before any study-related activities are performed.

Perioperative measures will include bowel preparation with Fleet Phospho-soda, preoperative shaving with electric clippers 1 hour before the operation, and intravenous prophylactic antibiotic administered 30 minutes before the incision, and repeated in OR if the operation lasts more than 3 hours, and discontinued within 24 h after the operation. In all procedures, chlorhexidine solution will be applied to the skin to achieve preoperative skin antisepsis, and the usual reusable or disposable surgical gowns, drapes, and gloving will be used. The type of surgical procedure will be a colorectal resection for any malignant or benign condition of the colon, rectum or anal canal via a laparotomy wound. The type of incision will either be a vertical midline or transverse abdominal incision. Laparotomy wound will be closed primarily as a mass closure technique utilizing polydioxanone (PDS) or Nylon suture. Skin and subcutaneous tissues will be approximated using stainless-steel staples.

During the surgery, assessment of eligibility (including wound classification) will be completed, and if eligible, the participant will be randomized to one of the two treatment arms - group A (conventional dressing) or group B (Prevena dressing). The randomization scheme is described later in the protocol. After the surgical wound is closed, the assigned dressing - conventional dressing (Mepore) or Prevena dressing - will be applied.

For participants in group A (conventional dressing) the wound will be inspected on an as needed basis during postoperative days 1-6 to assess for SSI (where day 0 = day of surgery). On postoperative day 7, the dressing will be removed. If the participant is in hospital, the wound care nurse or study staff will remove the dressing and examine the wound for SSI. If the participant was discharged before postoperative day 7, the home care nurse or the participant's physician will remove the dressing. The patient will have been sent home with a Post-Op Day 7 follow-up form, and will have been instructed to provide the form to the home care nurse or their physician to complete for the assessment for SSI.

For participants randomized to group B (Prevena dressing), the wound care nurse or study staff will inspect the dressing daily during postoperative days 1-6 (where day 0 = day of surgery) to assess for proper functioning of the Prevena dressing. If the participant is discharged before postoperative day 7, the wound care nurse or study staff will contact the participant daily to check for proper functioning of the Prevena dressing. On postoperative day 7, the Prevena dressing will be removed. If the participant is in hospital, the wound care nurse or study staff (residents or Surgeons) will remove the dressing and assess the wound for SSI. If the participant was discharged before postoperative day 7, the home care nurse or the participant's physician will remove the dressing. The patient will have been sent home with a Post-Op Day 7 follow-up form, and will have been instructed to provide the form to the home care nurse or their physician to complete for signs of SSI.

If SSI is suspected, the participant will be advised to visit the clinic for assessment of SSI by the study team. In case it is not possible for the participant to visit the clinic for assessment of SSI by the study team, the participants will have been sent home with a SSI Confirmation form to be completed by the participant's physician.

The wound care nurse or study staff will conduct post-discharge follow-up on postoperative days 14 (± 2 days) and 21 (± 2 days) by telephoning the family physician or the participant to check whether there are signs of SSI. If SSI is suspected, the participant will be advised to visit the clinic for assessment of SSI by the study team. If not possible, the participant will be instructed to ask their physician to complete the SSI Confirmation form.

On postoperative day 30 (± 7 days), the participant will be seen in the clinic by the treating surgeon as a part of the treatment and follow-up plan, and the wound will be assessed for SSI. For participants who are not able to come to the clinic, the study team will contact the participant or the family physician by telephone to check whether there are signs of SSI. If SSI is suspected, the participant will be advised to visit the clinic for assessment of SSI by the study team. If not possible, the participant will be instructed to ask their physician to complete the SSI Confirmation form.

As described above, each participant will have up to 12 study visits (11 scheduled visits, including the day of surgery, plus one clinic visit if there is suspicion of SSI). At any point, however, once SSI is confirmed, the participant will undergo no further study visits.

Inclusion Criteria:

1. Age equal or greater than 18 years
2. Patient undergoing colorectal resective surgery for any reason (benign or malignant) such as diverticular disease, colorectal cancer or inflammatory bowel disease through a laparotomy wound
3. Class II surgical wound
4. Laparoscopically assisted colorectal procedure

Exclusion Criteria:

1. Patient requires emergent or urgent operation
2. Patient has advanced colorectal malignancy associated with peritoneal carcinomatosis
3. Class III or IV surgical wound
4. Laparoscopic surgery involving intracorporeal colorectal resection and anastomosis
5. Patient has a previous disfigured midline laparotomy surgical scar requiring wide excision of skin, subcutaneous tissue, fascia and muscle