A Synergistic Patient-Specific Approach for Enhanced Spinal Fixation Using a Novel Flexible Pedicle Screw and a...

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Robotics

Background:

• Current spinal fixation (SF) techniques using rigid pedicle screws (RPS) often fail in osteoporotic patients due to poor bone mineral density (BMD).
• Rigid screws are constrained to linear trajectories, leading to loosening and pullout challenges in weakened vertebrae.

Purpose of the Study:

• To develop and validate a patient-specific, synergistic approach for spinal fixation using a novel Flexible Pedicle Screw (FPS) and a steerable robotic system.
• To overcome the limitations of conventional SF by enabling curved screw trajectories for enhanced fixation in osteoporotic bone.

Main Methods:

• A patient-specific framework guided the synergistic design of the Concentric Tube-Steerable Drilling Robot (CT-SDR) and the FPS.
• The FPS was designed, validated using Finite Element Analysis (FEA), and fabricated using Direct Metal Laser Sintering (DMLS).
• Experimental assessment of FPS morphability and self-tapping capabilities was performed in simulated bone using the CT-SDR system.

Main Results:

• The Flexible Pedicle Screw (FPS) demonstrated successful morphability, adapting to curvilinear paths.
• Effective self-tapping and fixation in simulated osteoporotic bone were achieved with the FPS and CT-SDR system.

Conclusions:

• The integrated FPS and CT-SDR system offers a flexible, patient-specific solution to enhance screw anchorage and fixation strength in osteoporotic vertebrae.
• This transformative approach has the potential to significantly reduce fixation failure rates in spinal surgeries for osteoporotic patients.