Reducing Wound Tension with Undermining or Imbrication-Do They Work?

Abstract

Background: For the noncolonized wound, achieving tension-free, primary wound closure is ideal. Some surgeons advocate imbrication of deeper tissues rather than undermining, posing that imbrication preserves more dermal perfusion while still reducing tension at the wound edge. We sought to determine which technique most reliably reduced wound tension while preserving dermal wound perfusion.

Methods: A total of 5 standardized, symmetrical pairs of full thickness wounds were created on Duroc swine. Wound tension was measured with a Tyrolean tensiometer before and after either method of closure, whereas a speckle contrast imager was used to assess dermal edge perfusion. Skin tension and dermal perfusion were evaluated for statistical significance via paired t tests and a multivariate analysis of variance.

Results: There was a significant reduction in wound tension with undermining and imbrication relative to the raw wound tension (5 and 5.9 vs 7.1 N; P < 0.05) yet no significant difference between methods of closure (P > 0.05). There was a significant reduction in dermal perfusion between unwounded skin and the imbricated wound (222 perfusion units [PU] vs 48 PU; P < 0.05) and between the unwounded skin and the undermined wound (205 vs 63 PU; P < 0.05).

Conclusions: We found no significant difference in wound tension between wound undermining or imbrication and a significant decrease in dermal perfusion after imbrication and undermining although the relative decrease in perfusion was greater with imbrication. Wound undermining reduces skin tension with greater relative dermal perfusion to the skin and should be selected over wound imbrication in standard primary wound closure.

Figures

Fig. 1.

Schematic showing how wounds were measured in the study. Full-thickness wounds were excised in Duroc swine, and raw tension was measured after bringing the raw wound together, the wounds were then closed with either undermining or imbrication, and postclosure tension was measured with a Tyrolean tensiometer.

Fig. 2.

A speckle contrast imager was used to assess skin perfusion before and after wounding. The images reflect the perfusion after staple closure, undermining, and imbrication. The grid below the image indicates the intensity where red regions represent blood flow and blue regions represent areas without blood flow.

Fig. 3.

Raw, imbricated, and undermined wound tension values (N). There is a significant reduction in wound tension with either undermining or imbrication relative to the raw wound, but no significant reduction in tension exists between the methods of closure.

Fig. 4.

Preexcision, raw, and undermined or imbricated wound perfusion values (PUs) using a speckle contrast imager. There is a significant decrease in wound perfusion with imbrication and undermining.

Fig. 5.

Relative dermal perfusion of both wound closure techniques relative to preexcision perfusion showing a greater relative perfusion with wound undermining relative to imbrication. The difference is not significant.