The articular surface technique for lumbar pedicle screw placement: a 3D feasibility study

Area of Science:

• Spine surgery
• Orthopedic biomechanics
• Surgical technique innovation

Background:

• Traditional pedicle screws (TPSs) and cortical-based trajectory screws offer lumbar spine fusion stability but have unique failure risks.
• Existing techniques face complications like loosening and failure due to technical limitations.
• A novel pedicle screw placement technique through the vertebral superior articular surface is proposed.

Purpose of the Study:

• To evaluate a new pedicle screw trajectory through the articular surface for lumbar spinal fusion.
• To determine if this technique allows for larger screw utilization and maintains bone density.
• To compare the proposed technique with traditional methods regarding screw size and bone engagement.

Main Methods:

• Retrospective review of 50 lumbar CT scans from trauma patients (age 18-45).
• Virtual pedicle screw placement (L1-S1) using Brainlab software, mapping trajectories through the superior facet and pedicle.
• Assessment of screw parameters: medial angle <10°, length ≥30 mm, width ≥5.0 mm, and starting point measurements.

Main Results:

• 600 virtual screws placed; 525 (87.5%) were satisfactory.
• Pedicle width significantly increases in lower lumbar vertebrae (L3-S1).
• 72% of unsuccessful screw placements occurred in L1-L2, indicating suitability for lower levels.

Conclusions:

• The articular surface technique (AST) is a viable alternative for lumbar spinal fusion.
• AST potentially reduces soft tissue dissection compared to traditional methods.
• The technique appears most suitable for lower lumbar levels (L3-S1).