Closed Incisional Negative Pressure Wound Therapy Sponge Width and Tension Off-Loading: A Laboratory Model

Closed incisional negative pressure wound therapy (ciNPWT) has become commonplace in surgery. One mechanism ciNPWT may prevent incision site complications is by off-loading tension. This study aimed to find what width sponge using ciNPWT provides the most tension off-loading.A model was designed to test tension off-loading of a wound using ciNPWT. An incision was made in an anatomy model and closed with single stitch at the central axis. Force was applied tangentially using a force gauge at a steady rate until the wound dehisced at a peak force indicated by the 5-0 suture breaking. This was repeated 10 times for the following 4 trials: no ciNPWT and ciNPWT sponges cut a 3-, 6-, and 9-cm widths with 125 mm Hg of negative pressure.The mean peak force to dehisce the wound without ciNPWT was the lowest, 28.7 N. The mean force for the ciNPWT trials was 43.0, 38.7, and 36.4 N for V.A.C. sponges of 3, 6, and 9 cm in width, respectively. There was a statically significant difference among all the trials using one-way analysis of variance with Tukey posttest analysis with a P value of less than 0.0001.Closed incisional negative pressure wound therapy was shown to increase peak force required to dehisce an incision of up to 49.7% compared with closure without. There is an inverse relationship with sponge width and tension off-loading. The smaller the sponge, the more tension is off-loaded across the incision. Closed incisional negative pressure wound therapy with a 3-cm-wide sponge required the greatest peak force for dehiscence.