J. L. Van Eps1,2, J. S. Fernandez-Moure1,2, F. J. Cabrera2, A. Chaudhry7, S. Shajudeen7, R. Righetti7, W. Ellsworth1,3, B. J. Dunkin1,4,5, E. Tasciotti2, B. K. Weiner2,5,6 1Houston Methodist Hospital,Department Of Surgery,Houston, TX, USA 2Houston Methodist Research Institute,Department Of Nanomedicine, Surgical Advanced Technology Lab,Houston, TX, USA 3Houston Methodist Hospital,Department Of Surgery, Division Of Plastic Surgery,Houston, TX, USA 4Houston Methodist Research Institute,Methodist Institute For Technology, Innovation And Education (MITIE),Houston, TX, USA 5Weill Cornell Medical College,New York, NY, USA 6Houston Methodist Hospital,Department of Orthopedics & Sports Medicine,Houston, TX, USA 7Texas A & M University,Department Of Electrical & Computer Engineering,College Station, TX, USA
Introduction:
In the U.S. today, approximately 350,000 ventral hernia repairs (VHR) are performed yearly, making it one of the most common operations overall and an important target for improvement using novel techniques and materials. Although mesh repair has improved recurrence rates vs. suture repair, as many as 5% may still recur and other complications such as seroma or SSI are increased in this group. Literature demonstrates that improved metrics of early wound healing and tissue ingrowth can enhance repair strength and diminish infection; and PRP is a universally-available source of growth factors that may improve such metrics, but has never been applied to soft tissue healing and hernia repair. We hypothesized that the addition of PRP would cause greater early neovascularization within implanted polyester mesh and thus, overall repair strength and quality.
Methods:
Chronic ventral abdominal hernias were created in 16 male Lewis rats by incising the musculofascial abdominal wall at the linea alba, closing the overlying skin and allowing them to mature for > 28 days. Rats were randomly divided into two surgical groups – a control (C) group that would receive standard of care repair with Parietex® polyester mesh, and an experimental (E) group with mesh repair augmented by adding autologous PRP. All repairs were performed in an underlay fashion with mesh secured with eight circumferential interrupted prolene sutures. Autologous PRP was isolated by double-centrifugation of whole blood, platelets were quantified and concentrated to a standard 1×106 platelets/μL, and 200μL of PRP was applied directly to the mesh repair site at the time of implantation. Rats were sacrificed after 6 weeks, 3D ultrasound elastography analysis performed, and the specimens processed histologically with H&E and α-smooth muscle actin (α SMA) antibody IHC. Blinded observers then quantified samples for neovascularity and staining intensity.
Results:
No rats suffered complication requiring euthanasia or exclusion from study, but one rat in the group E suffered a postop seroma compared to 3 in group C. Rats treated with PRP had an average of 223.7 (+ 49) neovessels on histological analysis compared to 73.7 (+ 11.5) – a 3-fold difference. These vessels were subjectively larger and more mature as well. Staining with α SMA was significantly increased in Group E rats as well. On ultrasound analysis, the average elastic modulus at the tissue-mesh interface in experimental rats 46.5kPa (+ 5.3) was significantly higher (p<0.05) than control rats at 1.3kPa (+ 0.2).
Analysis:
Early neovascularization is known to enhance wound healing and mature tissue integration with mesh in VHR, and our data suggests that VHR can be improved with the addition of autologous PRP. This neovascularization seems to translate to improved overall repair strength and quality. Further investigation is warranted regarding the clinical utility of PRP in VHR.