Masden 2012.

Methods	Study design: randomised controlled trial Ethics and informed consent: the study was approved by the Georgetown University Institutional Review Board. Consent was not specifically stated, but those patients not capable of undergoing informed consent were excluded. Sample size calculation: yes Follow‐up period: mean 113 days ITT analysis: available‐case analysis Funding: 2 of the investigators are consultants for KCI, and the study was funded by the manufacturer of the intervention product.
Participants	Location: Columbus, Ohio, USA Intervention group: n = 50control group: n = 43 Mean age: intervention group = 61.3 years (range 40 to 101)control group = 61.3 years (range 38 to 86) Inclusion criteria: patients scheduled to undergo radial forearm free flap Exclusion criteria: "patients not capable of undergoing informed consent and those patients with tape allergies or who otherwise could not tolerate NPWT ... patients with lower extremity amputations distal to the forefoot were excluded"
Interventions	Aim/s: to evaluate the effect of NPWT on closed surgical incisions. Prospective randomised controlled clinical trial comparing NPWT to standard dry dressings on surgical incisions Primary: "to evaluate the effectiveness of NPWT in patients with multiple co morbidities" Secondary: "to evaluate factors that contribute to wound complication" Intervention/s in both groups: "the graft was covered with a single layer of paraffin gauze dressing (Jelonet, Smith & Nephew, UK); then, 3 sheets of polyurethane (high‐density foam, Nuris Luisa, Santiago, Chile) with a fenestrated silicone drainage tube between the layers was placed over the gauze and covered with a transparent adhesive dressing (Opsite, Smith & Nephew, UK) providing the vacuum seal. We used a double layer under the tube to prevent pressure ulcers at the bed of the suction tube" Group 1 (NPWT) intervention: "NPWT group ... underwent placement of a V.A.C. system (KCI, San Antonio, Texas) along the line of closure set at −125mmHg continuous pressure at the time of closure" Group 2 (control) intervention: "the control group ... received a standard dry sterile dressing consisting of a non adhesive silicone layer (Mepitel, Mölnlycke Health Care AB, Göteborg, Sweden) and a bacteriostatic single silver layer (Acticoat, Smith & Nephew, Hull, UK)" Study date/s: October 2008 to August 2010
Outcomes	wound infection dehiscence reoperation LOS Validity of measure/s: not stated Time points: "all incisions assessed on the third postoperative day ... and reassessed at the first outpatient postoperative visit, as well as any subsequent visit (the last recorded infection was at 66 days post surgery)". However, the abstract states that "average follow‐up was 113 days".
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Evidence: quote (from correspondence with the author): "used a randomization generator through Excel in groups of 8 (4 controls, 4 experimental)" Comment: adequate method
Allocation concealment (selection bias)	Low risk	Evidence: quote (from correspondence with the author): "when the patient was recruited ... they contacted one of the investigators and the patient was assigned to whichever group was next on the list" Comment: adequate method
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Evidence for participants: not possible Comment: unlikely to affect outcomes Evidence for personnel: not possible Comment: unlikely to affect outcomes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Evidence: quote: "the evaluations were performed by a member of the research team not involved in the enrolment or the operative treatment and, thus, were blinded as to randomization group" Comment: adequate method
Incomplete outcome data (attrition bias) All outcomes	Low risk	Evidence: quote: "twelve subjects were lost to follow up in the immediate postoperative period and were excluded from the final analysis" Comment: equal number of losses in both groups
Selective reporting (reporting bias)	Low risk	Comment: protocol unavailable, but expected outcomes reported
Other bias	Unclear risk	Comment: the standard dressing contained a silver layer, which may have influenced the outcome.