Abstract Body: Introduction
Hyaluronic acid-based biomaterial gels have recently shown initial success inducing angiogenesis and repair in treatment of neurovascular conditions including stroke and moyamoya disease. Preliminary findings while investigating the angiogenic effects of a biomaterial gel suggested the additional clinical benefit of unexpected skull regeneration at sites of its use, prompting the current investigation. An established osteogenic agent could augment or even replace current practices in neurosurgical site repair across various applications.

Methods
Twenty-six C57BL/6 mice were divided into control (n = 12) and biomaterial (n = 14) groups. All mice underwent a 2mm craniotomy of the left parietal bone under general anesthesia. The biomaterial group immediately received implantation of gel subdurally at the surgical site. The biomaterial investigated was a crosslinked hyaluronic acid (HA) gel.

High-quality photos of each surgical site were captured. The skin was then sutured to close the surgical site without replacing the skull flap.
After two weeks, mice were humanely euthanized, and skulls were harvested. High-quality photos of each surgical site were again captured, and healing was assessed using a combined scale which scored based on percentage of site healing, tissue appearance, and thickness. Scores were corroborated between two trained reviewers.

Results
Significantly increased healing scores were observed for craniotomy sites treated with the HA biomaterial vs. the untreated control sites (p<0.05 using two sample t-test). No significant difference was observed between healing outcomes in male and female animals.

Conclusion
The application of biomaterials used for angiogenic treatment of neurovascular disease shows additional significant potential in facilitating the healing process of neurosurgical sites. This may additionally enhance a range of neurosurgical treatments and site repair practices.