Electroactive Spinal Instrumentation for Targeted Osteogenesis and Spine Fusion: A Computational Study

Area of Science:

• Spine biomechanics and biomaterials engineering.
• Orthopedic surgery and spinal fusion research.
• Biomedical engineering and electrical stimulation.

Background:

• Direct current electrical stimulation shows potential for enhancing osteogenesis and spinal fusion.
• Current methods for electrical stimulation in spinal fusion are limited.
• Electroactive spine instrumentation offers a novel approach for targeted therapeutic electrical stimulation.

Purpose of the Study:

• To evaluate the efficacy of electroactive pedicle screws for targeted electrical stimulation in the lumbar spine.
• To assess the ability of electroactive instrumentation to enhance bone formation and interbody fusion.
• To investigate the role of screw design and stimulation parameters in optimizing therapeutic electrical fields.

Main Methods:

• A finite element model of the adult human lumbar spine (L4-L5) was developed.
• Electroactive pedicle screws were simulated for routing direct current electrical stimulation.
• Electrical field distributions were analyzed in various tissue compartments at different stimulation amplitudes and anodization patterns.

Main Results:

• Electroactive pedicle screws modulated the spatial distribution and intensity of electric fields in the lumbar spine.
• Anodized screws (50%) generated high-amplitude electric fields in the intervertebral disc space and vertebral body.
• Therapeutic electrical fields (>1 mV/cm) sufficient for osteoinduction were achieved in the target interbody region via anodized screws.

Conclusions:

• Selective anodization of electroactive pedicle screws enables focal delivery of therapeutic electrical stimulation.
• This technology provides a foundation for preclinical and clinical investigation of enhanced spine fusion.
• Integrated electroactive systems warrant further testing for inducing lumbar fusion in vivo.