Negative pressure wound therapy for skin grafts and surgical wounds healing by primary intention

Indications for the use of negative pressure wound therapy (NPWT) are broadening with a range of systems now available on the market, including those designed for use on clean, closed incisions and skin grafts. Reviews have concluded that the evidence for the effectiveness of NPWT remains uncertain, however, it is a rapidly evolving therapy. Consequently, an updated systematic review of the evidence for the effects of NPWT on postoperative wounds expected to heal by primary intention is required.

To assess the effects of NPWT on surgical wounds (primary closure, skin grafting or flap closure) that are expected to heal by primary intention.

We searched the following electronic databases to identify reports of relevant randomised clinical trials: the Cochrane Wounds Group Specialised Register (searched 28 January 2014); the Cochrane Central Register of Controlled Trials (CENTRAL; 2013, issue 12); Database of Abstracts of Reviews of Effects (2013, issue 12); Ovid MEDLINE (2011 to January 2014); Ovid MEDLINE (In-Process & Other Non-Indexed Citations 24 January 2014); Ovid EMBASE (2011 to January 2014 Week 44); and EBSCO CINAHL (2011 to January 2014). We conducted a separate search to identify economic evaluations.

We included trials if they allocated patients to treatment randomly and compared NPWT with any other type of wound dressing, or compared one type of NPWT with a different type of NPWT.

We assessed trials for their appropriateness for inclusion and for their quality. This was done by three review authors working independently, using pre-determined inclusion and quality criteria.

In this first update, we included an additional four trials, taking the total number of trials included to nine (785 participants). Three trials involved skin grafts, four included orthopaedic patients and two included general surgery and trauma surgery patients; all the included trials had unclear or high risk of bias for one or more of the quality indicators we assessed. Seven trials compared NPWT with a standard dressing (two of these were 'home-made' NPWT devices), one trial compared one 'home-made' NPWT with a commercially available device. In trials where the individual was the unit of randomisation, there were no differences in the incidence of surgical site infections (SSI); wound dehiscence, re-operation (in incisional wounds); seroma/haematoma; or failed skin grafts. Lower re-operation rates were observed among skin graft patients in the 'home-made' NPWT group (7/65; 10.8%) compared to the standard dressing group (17/66; 25.8%) (risk ratio (RR) 0.42; 95% CI 0.19 to 0.92). The mean cost to supply equipment for VAC® therapy was USD 96.51/day compared to USD 4.22/day for one of the 'home-made' devices (P value 0.01); labour costs for dressing changes were similar for both treatments. Pain intensity score was also reported to be lower in the 'home-made' group when compared with the VAC® group (P value 0.02). One of the trials in orthopaedic patients was stopped early because of a high incidence of fracture blisters in the NPWT group (15/24; 62.5%) compared with the standard dressing group (3/36; 8.3%) (RR 7.50; 95% CI 2.43 to 23.14).

Evidence for the effects of negative pressure wound therapy (NPWT) for reducing SSI and wound dehiscence remains unclear, as does the effect of NPWT on time to complete healing. Rates of graft loss may be lower when NPWT is used, but hospital-designed and built products are as effective in this area as commercial applications. There are clear cost benefits when non-commercial systems are used to create the negative pressure required for wound therapy, with no evidence of a negative effect on clinical outcome. In one study, pain levels were also rated lower when a 'home-made' system was compared with a commercial counterpart. The high incidence of blisters occurring when NPWT is used following orthopaedic surgery suggests that the therapy should be limited until safety in this population is established. Given the cost and widespread use of NPWT, there is an urgent need for suitably powered, high-quality trials to evaluate the effects of the newer NPWT products that are designed for use on clean, closed surgical incisions. Such trials should focus initially on wounds that may be difficult to heal, such as sternal wounds or incisions on obese patients.