Preclinical Evaluation of a Novel Dressing Used in Conjunction with Negative Pressure Wound Therapy

While reticulated open cell foam (ROCF) is a well-established dressing for use with negative pressure wound therapy (NPWT), tissue ingrowth may occur if the dressing is left in place for greater than 72 hours. A novel dressing able to utilize the advantages of ROCF while addressing this challenge has recently been created. Full-thickness excisional wounds were created along the spine of 11 swine. Dressings were applied and continuous negative pressure applied at -125 mmHg for seven days. Dressing changes were performed at day 4.

Three-dimensional wound images were acquired to examine the changes in wound volume. Analysis indicate there was significantly more wound fill with the novel dressing at 72.3% compared to ROCF at 41.5% at day 4. At day 7, the novel dressing filled the wound to 87%, which is also significantly greater than 68.6% by ROCF. Histopathology evaluations and morphometry measurements were completed to assess granulation tissue thickness and quality.

The novel dressing had significantly more granulation tissue than ROCF, 4.8 mm versus 1.8 mm, respectively. Interestingly, tissue ingrowth was limited to only ROFC-treated wounds. Although the collagen quality and maturity were comparable between dressings, the level of vasculature was greater with the novel dressing. In addition, peel testing was performed upon dressing removal to measure the force required to remove the dressings from the wound bed. As expected, there was an inverse correlation between peel test force and tissue ingrowth. The force required to remove the novel dressing at days 4 and 7 was significantly lower at 0.33N and 0.27N, respectively, compared to 1.99N and 7.81N for ROCF.

Results of this new study illustrate that this novel dressing induced more granulation tissue formation while eliminating tissue ingrowth, thereby potentially allowing for a longer-wear dressing.