2a a Method for the Consistent Creation and Quantitative Testing of Postoperative Pelvic Adhesions in a Porcine Model

Maureen E. Cheung¹, Bradford Fenton², M Michelle Evancho-Chapman³, Mark Kovacik⁴, Don Noe⁴, Nicholas Ree⁵, James Fanning², and Stephanie T. Lopina⁶. (1) Chemical and Biomolecular Engineering / Surgery, The University of Akron / Summa Health Systems, 511 E. Buchtel Ave / 525 E. Market Street, Akron, OH 44304, (2) Ob/gyn, Summa Health Systems, 525 E. Market St., Akron, OH 44304, (3) Surgery; Division of Surgical Research, Summa Health Systems, 525 E. Market St., Akron, OH 44304, (4) Orthepedics; Musculoskeletal Research Laboratory, Summa Health Systems, 525 E. Market St., Akron, OH 44304, (5) Pathology, Summa Health Systems, 525 E. Market St., Akron, OH 44304, (6) Department of Chemical & Biomolecular Engineering, The University of Akron, Akron, OH 44325

Introduction: Adhesions following surgery represent a significant problem often resulting in pain, disability, and additional surgeries. There are compounds available for the prevention of post-operative adhesions, but their effectiveness is difficult to assess. The assessment of methods and compounds for the prevention of postoperative pelvic adhesions is hampered by the lack of a quantifiable adhesion measurement technique. Currently accepted models of adhesion comparison are limited to qualitative methods with much potential bias and little comparability.

Objective: The purpose of this study was to develop a standard injury technique and quantitative assessment method to evaluate adhesion prevention by novel compounds.

Development: The primary focus of this research was the creation of an adhesion complex that was suitable to quantitative testing using the Material Testing System (MTS) and histological assessment. This led to several improvements on the initial idea that included improved stabilization technique, testing area, and injury precision.

Methods: A technique was developed to generate consistent and significant adhesions in a swine model that are suitable for quantitative assessment using a Material Testing System (MTS) machine platform. In this method, the uterine horns are cannulated and then attached to the pelvic sidewall using loose silk sutures. The underlying sidewall and adjacent uterine serosa are injured with electrocautery. Following a two week survival the entire complex of uterine horn and sidewall are excised en bloc and prepared for MTS testing.

Result: The MTS measures force by displacement, generating a quantitative assessment of adhesion strength, which can be analyzed and interpreted, while the histology confirmed that adhesion was present and being quantified as well as providing a comprehensive description of the vascularity, density, collagen content, and organization of the adhesion. Our assessments showed that previous visual grading methods were neither consistent nor accurate. This model is unique and advantageous in its ability to quantitatively assess the strength of the adhesion complex.

Discussion: This technique represents a novel quantitative method for adhesion assessment in an animal model. This quantitative technique may then be applied to accurately assess a range of adhesion prevention techniques, producing results which can be standardized for comparison.