Safety and efficacy of flowable microfibrillar collagen hemostat in an ovine model of craniectomy with intraparenchymal defect compared to gelatin-thrombin hemostatic matrix

Flowable hemostatic agents offer advantages in confined surgical spaces, particularly in neurosurgery. However, data on microfibrillar collagen hemostats (MCH) in these applications remain limited. This study evaluated the safety and efficacy of a novel flowable collagen and compared to a gelatin-thrombin matrix—in an ovine brain parenchymal injury model. Thirty-two sheep (19 female, 13 male; 44.6–69.0 kg) underwent bilateral craniectomy with durectomy to create dural and intraparenchymal defects. Twenty-seven animals were randomized into three groups (n=9): Flowable Collagen, Gelatin Matrix with human recombinant thrombin or Sham control (no hemostatic agent). Outcomes included time to hemostasis, hemostasis success rate, total tamponade time, and device characteristics (precision, migration, and swelling). Animals were euthanized at 7-, 45-, and 120-days for histomorphologic evaluation. Hemostasis was achieved within 3 minutes in 100% of Flowable Collagen sites, 78% of Gelatin Matrix sites, and 33% of Sham sites. Gelatin Matrix had the fastest mean time (2.0 minutes), followed by Flowable Collagen (2.6 minutes), both significantly faster than Sham (4.4 minutes; p<0.0001 and p=0.0001). Flowable Collagen exhibited no swelling or migration; Gelatin Matrix swelled in 16/18 cases and migrated in one. Inflammation decreased over time in all groups. Flowable Collagen demonstrated favorable tissue response and healing. Mild, transient neurological effects occurred across all groups, with no long-term adverse effects from the hemostatic agents. In a preclinical ovine model involving bilateral craniectomy with durectomy and intraparenchymal injury, Flowable Collagen hemostat demonstrated safety and efficacy comparable to Gelatin Matrix and superior to Sham control. • Hemostasis success: Flowable Collagen 100%, Gelatin Matrix 78%, Sham 33% within 3 min • Flowable Collagen showed no swelling or migration; Gelatin Matrix swelled in 16/18 cases • Healing improved with both agents and inflammation reduced over time • Flowable Collagen is safe and effective, comparable to Gelatin Matrix superior to no-treatment control