Three-year results from a preclinical implantation study of a long-term resorbable surgical mesh with time-dependent mechanical characteristics.

PURPOSE: The purpose of this study was to evaluate the biocompatibility, local tissue effects and performance of a synthetic long-term resorbable test mesh (TIGR(®) Matrix Surgical Mesh) compared to a non-resorbable polypropylene control mesh following implantation in a sheep model. METHODS: Full-thickness abdominal wall defects were created in 14 sheep and subsequently repaired using test or control meshes. Sacrifices were made at 4, 9, 15, 24 and 36 months and results in terms of macroscopic observations, histology and collagen analysis are described for 4, 9, 15, 24 and 36 months. RESULTS: The overall biocompatibility was good, and equivalent in the test and control meshes while the resorbable mesh was characterized by a collagen deposition more similar to native connective tissue and an increased thickness of the integrating tissue. The control polypropylene mesh provoked a typical chronic inflammation persistent over the 36-month study period. As the resorbable test mesh gradually degraded it was replaced by a newly formed collagen matrix with an increasing ratio of collagen type I/III, indicating a continuous remodeling of the collagen towards a strong connective tissue. After 36 months, the test mesh was fully resorbed and only microscopic implant residues could be found in the tissue. CONCLUSIONS: This study suggests that the concept of a long-term resorbable mesh with time-dependent mechanical characteristics offers new possibilities for soft tissue repair and reinforcement.

When to conduct a clinical trial.

A clinical trial is designed to provide clinical evidence of compliance with the medical device Directives. Clinical evidence can also be based on systematic and objective literature review. This article highlights when to use the clinical or the literature route to demonstrate the safety and performance of a medical device.

Use of a collagen-based sealant to prevent in vivo epidural adhesions in an adult rat laminectomy model.

OBJECT: The authors investigated the effect of a collagen-based sealant, Gel Amidon Oxydé (GAO), in the prevention of epidural scar adhesions in an adult rat model of laminectomy. METHODS: Seventy-two adult Sprague-Dawley rats underwent an L5-6 laminectomy, after which the dura mater and the left L-4 and L-5 nerve roots were exposed. In the 36 animals that received GAO, the sealant was applied over the dura and around the nerve roots, and it was used to fill the laminectomy cavity before it polymerized. In 36 control animals, the same surgical treatment was performed, but the rats did not receive GAO. During the early postoperative period, a significant decrease in the occurrence of epidural hematoma was found in the GAO-treated rats. In contrast to findings in control rats, a thin white connective tissue layer was found between the dura and surrounding muscles after GAO had degraded and been absorbed. One month posttreatment, no epidural scar adhesion was found between the tissue layer and the dura in the GAO-treated animals. Three months postoperatively, both gross inspection and histological examination further confirmed that formation of epidural adhesions was significantly inhibited in the rats treated with GAO. No special inflammatory reaction was observed, and the healing of skin and muscle lesions was not affected by either treatment. CONCLUSIONS: The data obtained in this study suggest that the GAO collagen-based sealant may be an effective biomaterial to prevent epidural adhesions in vivo after laminectomy.