An Investigational Pilot Study to Validate the Use and Efficacy of LifeGel™ following Epidural Application – An Ovine Laminectomy Model –

Introduction: The current pre-clinical 3 animal pilot study was performed to investigate the safety and effectiveness of LifeGel following epidural application using an in-vivo ovine laminectomy model. LifeGel is non-swelling hemostatic hydrogel which is able to manage mild, mild and moderate bleeding during epidural applications. Other available hemostatic agents swell, creating downstream safety risk to the patient, whereas LifeGel obviates this risk, through its soft, biocompatible, and non-swelling characteristics.

Methods: The spinous processes of L3 (superior) and L5 (inferior) levels of Crossbred Suffolk Sheep (Female, N=3) were resected followed by laminectomy to produce a defect of approximately 25mm length x 12mm wide. The dimensions (length and width) of each TBS (target bleeding site) were recorded. The important operative condition is that the exposed and treated levels were non-contiguous, with a single intervening non-operative level between the superior and inferior levels. Importantly, the LifeGel™ material application technique and quantity ensured complete coverage of the entire laminectomy surface and implanted as follows: In each sheep, one laminectomy site was randomly designated as ‘clinical’ and the second laminectomy site as ‘worst case.” Sheep were survived to timepoints of 30, 60 and 90 d respectively; extensive necropsies and histopathology of collected tissues were performed.

Results: The material applications were successfully performed and all three animals demonstrated ambulatory function within 3 hours post-operatively. Importantly, there was no visual intra-operative evidence of the LifeGel™ material swelling following application or immediately prior to wound closure. Based on clinical neurologic assessments, all animals demonstrated normal balance, weight bearing, gait and stride patterns by day 4 postoperatively. All bleeding sites were controlled by 3 minutes of LifeGel™ application. Extensive histopathologic review of the operative sites indicated residual LifeGel™ to decrease between each time interval, indicating progressive degradation. Treatment of the ovine lumbar spine with LifeGel™ (Test Article) showed excellent biocompatibility, advanced and nominal healing, and no adverse findings or safety concerns at all 3 time points.

Conclusion : LifeGel was shown to be effective in achieving hemostasis, and safe for implantation, in this pilot ovine laminectomy evaluation. Based on these outcomes, a larger investigation powered with appropriate sample sizes is warranted.