Evaluation of Closed Incision Negative Pressure Therapy with Foam-dressings: Effect of Dressing Width and Thickness on the Resistance to Distraction of a Closed Incision in Simulated Tissue

Introduction: Reduction of surgical site complications with closed incision negative pressure therapy (ciNPT) application may be partly attributed to incisional stabilization. While ciNPT with commercially-available foam-based dressings§ (2.5in width, 0.7in thickness) was shown to increase the force required to part/distract a simulated incision1, clinicians sometimes use narrower strips of the thicker (1.25in) foam-dressing¥ used with NPWT∂. This study evaluated the impact of foam-based dressing width and thickness on distraction-force.

Methods: Distraction-forces of a stapled incision in a 3-layer polymeric tissue analog 10mm (0.39in) were determined under 3 conditions:

• Without dressing

• With dressing without NP (polyurethane-ether foam¥ of similar lengths [9in], 2 thicknesses [0.7in, 1.25in], each with varying widths [0.5in, 1.0in, 1.5in, 2.0in, 2.5in], with interfacial layers* of similar footprint and 1.75in drape borders).

• With dressing under negative pressure (NP; -125 mmHg).

Least Squares Means with Tukey Adjustment was used to compare groups (n=3/group).

Results: Dressings without NP increased distraction-force from 38.4N-38.9N without dressing to 43.5N-46.2N for thicker dressings but were not width-dependent unlike the thinner dressings that had subtle, yet, consistent width-dependent increases (44.1N [0.5in width] to 46.9N [2.5in width]; p<0.05). NP greatly increased distraction-force in a width-dependent manner (p<0.05). Thickness may have had a small effect on narrower widths (0.5in width: 48.9N±0.1[SEM]N [thinner dressing] vs 50.4N±0.4N (thicker dressing), 1in width:51.7N±0.6N vs 54.6N±2.3N, 1.5in width; 56.2N±0.9 vs 58.6N±0.4), but not on wider dressings (2in width: 63N±0.9N vs 63.8N±0.3N; 2.5in width; 71.5N±0.5N vs 70.9N±0.5N).

Discussion and Conclusions: Incisional distraction-force increased significantly with foam-based dressings without NP, with a slight dependence on width for thinner dressings. NP further increased distraction-force for all widths but more so for wider dressings. Narrower dressings that were thicker may have had slightly greater distraction forces than the thinner dressings but this effect was abrogated for the wider dressings. Clinical implications of these findings need further study.