Healed porcine incisions previously treated with a surgical incision management system: mechanical, histomorphometric, and gene expression properties

Abstract

Background: Computer and bench models have shown previously that surgical incision management with negative pressure (SIM) immediately decreases lateral tissue tension and increases incisional apposition. Better apposition is known to improve healing. Thus, SIM was hypothesized to improve the quality of incisional healing. This study evaluated the impact that 5 days of SIM had on mechanical properties and associated changes in the histology/histomorphometry and gene expression of healed porcine incisions.

Methods: One incision in each of the 4 pairs of contralateral, sutured, full-thickness incisions in each of 6 Yucatan swine were treated with either SIM (Prevena™ Incision Management System; n = 24 incisions/treatment group) or standard of care (SOC; sterile absorbent abdominal pads; n = 24/group) for 5 days, after which both groups received SOC for an additional 5 days. Biopsies for gene-expression analyses were collected on days 5 (n = 6 pairs/group), 20 (n = 6 pairs/group), and 40 (n = 12 pairs/group). On day 40, the animals were killed, after which healed incisions were harvested for mechanical testing (n = 12/group) and histologic/histomorphometric evaluation (n = 12/group).

Results: Compared with SOC-treated incisions, SIM-treated incisions had significantly improved (p < 0.05) mechanical properties (strain energy density, peak strain) and a narrower scar/healed area in the deep dermis on day 40. Differences in gene expression between SOC- and SIM-treated specimens were observed primarily on day 5. The SIM-treated specimens had significantly fewer genes, which were differentially expressed and showed reduced upregulation of genes associated with inflammation, hypoxia, retardation of reepithelialization, impaired wound healing, and scarring.

Conclusion: Early application of SIM improved the quality of healed porcine incisions in terms of mechanical, histomorphometric, and gene-expression properties.

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