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Development of Stabilimax NZ From Biomechanical Principles

Manohar M. Panjabi, PhD,1 Jens Peter Timm, BS2

1Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Conn 2Applied Spine Technologies Inc, New Haven

Abstract 

Background

Traditionally, spinal degeneration and injury have been associated with abnormal intervertebral motion; thus, treatment for lowback pain has centered on prevention of motion through spinal fusion. Although the rate of successful spinal fusions is improving, complications such as adjacent-level syndrome emphasize the need to develop alternatives for treating spinal degeneration. In an effort to improve the clinical outcomes associated with such treatment, we hypothesized that spinal stabilization and a consequent reduction in symptoms is achievable without the harsh restrictions to spinal motion imposed by fusion. This idea was based on the principle of the neutral zone and the neutral zone hypothesis of back pain.

Development

Performance requirements for a novel device were determined through a series of biomechanical experiments. From these data, the Stabilimax NZ was developed to provide stabilization to a degenerated or surgically destabilized spine while maintaining the maximum possible total range of motion. Applied Spine Technologies Inc has tested 70 bilateral assemblies of the final design of the Stabilimax NZ, and all exceeded the biomechanical, static, fatigue, wear, and histological requirements necessary to initiate clinical investigation.

Discussion

The Stabilimax NZ device has been systematically designed and tested under protocols developed by Applied Spine Technologies in conjunction with Panjabi, Patwardhan, and Goel. The device decreased the neutral zone in destabilized spines while maintaining substantial range of motion.

Clinical Relevance

Development testing has been submitted to the US Food and Drug Administration and permission obtained to initiate an investigational device exemption trial to clinically investigate the efficacy of the Stabilimax NZ device.

keywords: 
neutral zone, dynamic stabilization
Volume 1 Issue 1
doi: 
10.1016/S1935-9810(07)70040-3