Negative Pressure Wound Therapy for At Risk Surgical Closures: A Prospective Randomized Controlled Study

PURPOSE:

Recently the use of negative pressure wound therapy (NPWT) on surgical incisions has emerged as an option to assist healing following surgical closure.  We performed the largest prospective randomized controlled clinical trial comparing NPWT to dry dressings on surgical incisions.

METHODS:

Patients undergoing primary wound closure at a busy referral center were randomized to NPWT or a dry occlusive dressing over their incision at the end of surgery.  All dressings were removed at post-op day 3 and evaluated routinely in clinic.  Endpoints included post-op infection, wound dehiscence and reoperation. Multivariate regression and Kalpan-Meyer analyses were performed

RESULTS:

43 patients were randomized to receive dry dressings, and 50 to receive NPWT (n=93). Average follow up time was 123 days. The majority of closures occurred in the lower extremities with the lower leg the most common (54%), followed by the foot (18%), thigh (17%), and trunk (11%). There were no statistically significant differences between the two groups with regards to pre-operative co-morbidities or operative details. 6.8 % of the NPWT group and 13.5% of the dry dressing group developed wound infection (p=0.46).  For patients who developed infection, foot wounds became infected earliest (17 days), followed by leg (29 days), and trunk (65 days); this was statistically significant (p=0.01). There was no statistically significant difference in the incidence of dehiscence between the NPWT and dry dressing group (36.4% vs. 29.7%; p=0.54).  Mean time to dehiscence was 33 days for the NPWT group and 60 days for the dry dressing group, this was not statistically significant (p=0.45).  Similar to post-op infection, foot wounds dehisced earliest (22 days), followed by leg (33 days), and trunk wounds (66 days); this was statistically significant (p<0.0001). Overall, 35% of the dry dressing group and 40% of the NPWT group had a wound infection, dehiscence or both.  Of these, 9 in the NPWT group (21%) and 8 in the dry dressing group (22%) required reoperation.

CONCLUSIONS:  There does not appear to be a significant benefit to negative pressure wound therapy with regard to infection or dehiscence when applied to these at risk surgical closures.  A trend to lower infection rates is suggested with NPWT. Post operative wound infection and dehiscence occurs earlier with more distally located wounds.