Reinforcement of Midline Laparotomies with Bioabsorbable Mesh: Implications on Wound Healing and Infection

Andrew Victory, Medical, Student, Joe Drosdeck, MD, Brendan Marr, MD, Mark Wendling, MD, Jonathan Rock, MD, Alan Litsky, MD, ScD, Mario Salazar, MD, Aliyah Kanji, MD, W.Scott Melvin, MD

The Ohio State University Wexner Medical Center

Treatment of incisional hernias incurs significant financial and human costs. Prosthetic mesh implants reduce hernia rates, but recurrence and infection remain unacceptably high. Synthetic mesh provides the most effective treatment, but risk of infection significantly limits its prophylactic use in most gastrointestinal surgery. Prophylactic biologic reinforcement is a potential solution. Biologic mesh has shown promise in preventing incisional hernias in specific settings. This study investigates the ability of bioabsorbable polygycolic acid/trimethylene carbonate fibrous (Bio-A) mesh to facilitate wound healing in a porcine model.

Methods and Procedures
Twenty-two female domestic swine received supra- and infraumbilical vertical midline incisions under general anesthesia. A small bowel resection with primary anastomosis was performed via each infraumbilical incision. Each subject was randomized to receive a 12×4 cm piece of Bio-A mesh in the supraumbilical (n = 11) or infraumbilical (n = 11) subfascial location. The mesh was fixed with absorbable sutures and the overlying fascia closed primarily with running O-loop Maxon. The subcutaneous layer and skin were closed primarily in layers in running fashion. Animals were then returned to housing and fed normally.

Subjects were euthanized at 12 weeks and a strip of abdominal wall surrounding each incision was harvested. Specimens were cleaned of skin and subcutaneous fat, trimmed, and notched above and below the incision before testing; final dimensions were 14×3 cm. All specimens were placed in clamps and stretched in-line with a MTS Bionix 858 axial-torsional servo hydraulic materials test system until breaking strength. Peak load was defined as the maximum force achieved before wound failure. Histological evaluation of each specimen was performed to evaluate wound healing properties between groups.

All wounds were well healed and showed no evidence of superficial or deep infection. Average maximum loads were similar between wounds reinforced with Bio-A mesh (311.34 N, SD 84.94) and those in the control group (309.14 N, SD 100.91). Of the 32 wounds that underwent mechanical testing, infraumbilical wounds had lower strengths than supraumbilical wounds. Adhesions were not noted when the prosthesis was placed above the peritoneum. Two animals died prematurely: one from anastomotic breakdown at the site of the small bowel anastomosis, one from small bowel obstruction as a result of mesh-related adhesions.

Placement of Bio-A absorbable mesh in vertical midline abdominal incisions yields equivalent maximum wound tensile strength compared to primary fascial closure in a porcine model and does not increase wound infections. Intraperitoneal placement was associated with a higher adhesion score.

Session: Poster Presentation

Program Number: P276

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