135 - The Feasibility of a Novel Hydrogel Intradiscal Implant for Nucleus Au...

Oral Posters: Innovative Technologies

Presented by: A. Yeung - View Audio/Video Presentation (Members Only)

Author(s):

A. Yeung(1,2), R. Morganstern(3), M. Knight(4), J. Yue(5), A. Prewett(6)

(1) University of New Mexico School of Medicine, Neurosurgery, Phoenix, NM, United States
(2) Desert Institute for Spine Care, Phoenix, AZ, United States
(3) Centro Medico Quiron Teknon, Barcelona, Spain
(4) Spinal Foundation, Manchester, United Kingdom
(5) Yale School of Medicine, New Haven, NH, United States
(6) Replication Medical, Cranbury, NJ, United States

Abstract

Introduction: Non-operative treatments often fail to achieve effective relief in chronic, discogenic back pain. Surgical options range from endoscopic intradiscal therapy with electro-thermal or laser therapy to lumbar fusion. Discectomy is a surgical treatment when discogenic pain progresses to disc herniation caused by failure of the annulus fibrosis, validated by the SPORT study. Transforaminal surgical decompression with thermal annuloplasty is the current most effective treatment, especially if endoscopically visualized. Materials and

Method: Hydrolyzed Polyacylonitrile hydrogel is a nucleus implant with a CE mark that focuses on providing hydraulic support to the nucleus rather than nucleus replacement or just decompression and ablation. The nucleus is augmented through an implant inserted through a thin walled18 gauge needle in patients with discogenic pain confirmed by evocative discography. The desiccated, spaghetti shaped hydrogel “sticks” expand 4-5 times in volume with hydration that neutralizes the acidic pH of the disc and provides hydraulic support. In 188 cases with three year follow-up, hydrogel implants were also inserted into desiccated discs in patients with stenosis needing foraminoplasty. Results were better than foraminalplasty alone.

Results: Overall favorable results for pilot studies, performed in Spain, England, Germany, and Asia, demonstrate its efficacy and safety with results better than discectomy alone as measured by VAS, Oswestry, and patient satisfaction. The studies demonstrate very high clinical efficacy rate with few extrusions or procedure related complications. The soft, spaghetti like hydrated implants resist extrusion in an intact annulus provides immediate hydraulic support, and elevation of the Ph in the acidic degenerative disc.

Discussion: Chronic lumbar discogenic pain is a difficult condition to treat, because its pathogenesis is multifactorial and only partially understood. Non-operative therapeutic methods often fail to achieve sufficient pain relief because chemical irritants emanate from the degenerating disc and irritate the spinal nerves and DRG through annular tears. Epidural steroids may be effective in the temporary relief of back pain and sciatica, but are less successful long term in resolving low back pain. Surgical options vary greatly, ranging from surgical disc decompression (Sport study) to 360° fusion. Surgical morbidity associated with all fusion techniques, however, while more thoroughly studied, is significant when considering only 65 - 80 % of patients obtain satisfactory longer term clinical results. The morbidity of fusion for back pain often creates more problems with adjacent level degeneration or when the procedure fails. Chymopapain, the only intradiscal procedure to be validated by Level 1 evidence based medicine is no longer available due to abandonment by industry. Profitability and liability issues, including transverse myelitis and anaphylactic shock, caused manufacturers to cease manufacturing this effective intradiscal “drug”, regulated as such by the FDA. The current trend in Endoscopic MIS Spine are surgical procedures focusing on intradiscal therapy. Other intradiscal therapies have emerged, but all have focused on the elimination of pain in a degenerating disc by decompression, ablation, irrigation, or oxidation, but not nucleus augmentation.

Conclusion: Pilot studies on intradiscal augmentation demonstrate very high clinical efficacy rate with almost no complications. The NeuSTX nucleus augmentation option is a procedure focused on replacing and augmenting the nucleus .with and without endoscopic decompression.Favorable results in preliminary pilot cases warrant further study.