Biomechanical evaluation of an interfacet joint decompression and stabilization system

Area of Science:

• Orthopedics
• Spine Surgery
• Biomedical Engineering

Background:

• Cervical spondylosis affects many middle-aged individuals, often necessitating spinal decompression and fusion.
• Minimally invasive cervical fusion offers reduced operative time, morbidity, and mortality.
• A novel interfacet joint spacer (DTRAX facet screw system) aims for minimally invasive deployment, neuroforaminal decompression, and interfacet fusion.

Purpose of the Study:

• To evaluate the effectiveness of the interfacet joint spacer in minimizing intervertebral motion for fusion.
• To assess nerve root decompression during bending and implant performance under repeated loads.
• To investigate the device's ability to promote fusion and maintain anatomical integrity.

Main Methods:

• Biomechanical testing on cadaveric cervical spine models using the interfacet joint spacer (FJ spacer) in stand-alone and anterior plating configurations.
• Assessment of flexion, extension, lateral bending, and axial rotation range of motion (ROM).
• 3D imaging for foraminal area quantification and cyclic loading (30,000 cycles) to evaluate implant loosening.

Main Results:

• The FJ spacer increased specimen stiffness in all directions except extension.
• 86% of deployments achieved foraminal distraction, maintained across various postures.
• Minimal implant loosening was observed, with most specimens showing no or subclinical loosening (<0.5 mm).

Conclusions:

• The FJ spacer system effectively increases cervical spine stiffness, comparable to existing minimally invasive technologies.
• The device demonstrated potential for increasing foraminal area and maintaining decompression during bending.
• Results are promising for further investigation in animal and clinical trials for treating cervical radiculopathy.