EARLY CLINICAL RESULTS OF AN IN SITU POLYMERIZING PROTEIN HYDROGEL NUCLEAR REPAIR SYSTEM.

Abstract

Purpose: We present the early results of a pilot study of 10 patients evaluating the basic safety and performance of an in situ polymerising protein hydrogel used in discectomy to prevent recurrent nuclear herniation, reduce motion segment instability and preserve disc height.

Method: Patients with radicular symptoms due to a MRI scan proven disc herniation, failed at least 3 months of conservative therapy, and had mild to moderate disc space narrowing. A standard open discectomy was performed to create a cavity for the implant, which was injected into the void through the annulotomy. The implant polymerised within 2 minutes. All patients had standard post-operative care for open discectomy.

The patients were assessed pre-operatively and post-operatively at 6 weeks, 3, and 6 months using Visual Analogue pain scale (VAS), Oswestry Disability index (ODI), SF-36 Health Survey (SF-36) and positional MRI scan in sitting (flexion, extension and neutral), erect and supine positions. To date, seven patients have a six-month follow up.

Results: Six females and 4 males were implanted into either the L4/L5 (5 patients) or L5/S1 (5 patients) level. The mean age of the patients was 40.6 years with a range of 19–57 years. ODI decreased from a mean of 49.2 pre-operatively to a mean of 11 at 6 months, and numerical pain score from of 5.86 to 1.62. Physical Component Score improved from a mean of 28.52 pre-operatively to 48.10 at 6 months. Two patients have suffered recurrent herniation, male (L5/S1) at 10 days, and a female (L5/S1) at 8 months, both requiring surgery.

Conclusion: Early clinical results indicate that the material can be used to fill the nuclear void following discectomy. Long-term data will be collected and evaluated to determine its efficacy in reducing spinal segment instability and preserving disc height.