Safety and efficacy of flowable microfibrillar collagen hemostat in an ovine model of lumbar laminectomy and open durotomy compared with the gelatin-thrombin hemostatic matrix and control.

Background: Effective hemostasis in spinal surgery is critical, especially near sensitive structures such as the spinal cord and dorsal root ganglia. Flowable hemostatic agents offer targeted control in irregular, hard-to-reach areas. This study evaluates the safety and efficacy of flowable collagen hemostat (FC) in an ovine lumbar laminectomy model with open durotomy by making a direct comparison with the gelatin hemostatic matrix with thrombin (GM) and a no-treatment control (Sham). Methods: Fifty-four Polypay sheep (27 F, 27 M) underwent lumbar laminectomy and open durotomy and then received FC, GM, or no treatment ( Results: Hemostasis was achieved in 100% of FC-treated sites, 94.4% of GM, and 72.2% of Sham. Sham-treated animals exhibited more severe and prolonged neurological deficits compared with those treated with FC or GM. Inflammation decreased significantly across all groups, from mild/moderate on day 7 to minimal on day 45, and was barely detectable by day 120. FC was associated with favorable histological responses in both intradural and extradural spinal tissues, comparable to GM and Sham. Conclusion: Flowable collagen hemostat was safe and effective when applied directly to the spinal cord and surrounding neurological tissues during laminectomy with open durotomy. Its performance was comparable to that of the gelatin hemostatic matrix with thrombin in terms of hemostatic efficacy and histological outcomes, with both agents demonstrating superior neurological recovery compared with the untreated Sham group.