Seroma Formation in Rat Latissimus Dorsi Resection in the Presence of Biologics

Abstract

Seroma formation is a well-recognized complication associated with many operative procedures. Despite its ubiquity, a lack of definitive scientific understanding of the etiology, natural history, and biochemistry of seromas remains. We endeavored to create and examine seromas in a rat model in the setting of commonly used biologic implants and to examine the role of quilting sutures/mechanical fixation in mitigating seroma development. Female Sprague-Dawley rats were assigned to either Quilting or Nonquilting groups then subdivided into one of 3 porcine dermal implant groups (Permacol Surgical Implant, Strattice Reconstructive Tissue Matrix, or XCM Biologic Tissue Matrix) or control group. A 5-cm midline back incision was made, the skin reflected and the latissimus dorsi muscle resected bilaterally. Implants were sutured into the surgical bed using a running suture. The skin of nonquilted rats was closed with a running subcuticular suture. Quilted rats underwent placement of absorbable quilting sutures spaced 2 cm apart between the skin and underlying implant or muscle before skin closure. Postoperatively, rats were monitored for seroma formation with fluid aspirated as needed. At 28 or 90 days, rats were euthanized. Seroma and implants were examined grossly and under light microscopy. Of nonquilted rats, 42/54 (78%) developed seromas compared with 19/46 (41%) of quilted rats (P < 0.05), defined by bursa cavity present at necropsy. When a biologic implant was present, 28/35 (80%) of nonquilted rats developed seromas compared with 12/33 (36%) of quilted rats (P < 0.05). In the control group, 14/19 (74%) of nonquilted rats developed seromas compared with 7/13 (54%) of quilted rats. This difference was not statistically significant. Bursa presence was confirmed histologically in all cases, with no difference in bursa character seen between groups. This study confirms a reliable rat model of seroma formation, with most of the rats exhibiting at least subclinical seromas. There was no difference in seroma formation rate in the presence of biologic implants, and no differences in bursa character between implants. Mechanical fixation with quilting sutures decreased seroma rate significantly in all subgroups. All rats with seromas at necropsy had histological evidence of a bursa with no difference in appearance between groups.