Engineering Innovations: Identification of Optimal Intraoperative Solutions for CSF Leakage Reduction in Spinal Surgery

Introduction: Dural tears are a significant risk factor for spinal surgery, with an incidence of over 5%. They may lead to cerebrospinal fluid (CSF) leakage and clinical sequelae (postural headache), and procedural costs increase by $4000 following an incidental durotomy. Currently, treatment is focused on either pre-operative prevention or intra-operative repair of tears. Sutures and biomaterial adhesives fall into the latter and are most common; however, they do not guarantee leakage reduction. There is a need for a more reliable intraoperative method of closing dural tears in patients undergoing spinal procedures to reduce repeat post-operative encounters and complications from CSF leakage.

Methods: Guided by the Stanford Biodesign process and consulting expert stakeholders to address this complex issue, we investigated the biomechanical aspects of dural tears. Another goal was to characterize better the shortcomings of the aforementioned traditional dural tear repair methods.

Results: We found that current collagen and hydrogel adhesive products do not seal the dural tear quickly enough to stop the leak of CSF and are liable to be diluted by the leakage of CSF. Additionally, hydrogels can swell up to 12% and are not always safe for bony confined areas. Sutures can be difficult for certain tissue morphologies and may cause new microtears.

The ideal solution would quickly seal the dura, function in wet conditions, be biocompatible, fit within the surgical window, avoid damaging spinal components, require minimal training, and reinforce the dura for suturing. This may require the integration of a non-traditional deployment mechanism and unique biomaterials, e.g. biphasic polymers, functionalized chitosan, etc.

Conclusion : According to neurosurgeon feedback and the documented incidence of post-surgical CSF leakage, current durotomy repair methods need improvement. The estimated potential addressable market for such a solution is $90M and would greatly improve the potential morbidity associated with dural tears. Ultimately, it was found that an improved solution entails immediate, robust interaction with the dura to reduce the incidence of CSF leakage.