Posterior spinal instrumentation and decompression with or without cross-link?

Area of Science:

• Spinal Surgery
• Biomechanics
• Orthopedic Research

Background:

• Posterior lumbar instrumentation stability is crucial for bony fusion and preventing implant failure.
• Transverse cross-link (CL) connectors can enhance construct stiffness but their impact during decompression is unclear.
• This study investigates CL augmentation's effect on lumbar instrumentation stiffness post-decompression.

Purpose of the Study:

• To evaluate the impact of CL augmentation on single-level lumbar instrumentation stiffness.
• To assess changes in range of motion (ROM) after gradual decompression procedures with and without CLs.

Main Methods:

• Seventeen human cadaveric lumbar segments were instrumented with pedicle screw-rod constructs.
• ROM was measured in six loading directions before and after sequential decompression (unilateral laminotomy, bilateral laminotomy, facetectomy with TLIF).
• Tests were conducted with and without CL augmentation.

Main Results:

• CL augmentation significantly reduced axial rotation (AR) ROM by 7-12%, with greater reduction after extensive decompression.
• Slight, statistically significant reductions in flexion/extension (FE) were noted after facetectomy and TLIF (3%).
• No significant differences were found across instrumentation levels.

Conclusions:

• CL augmentation provides a modest reduction in AR-ROM (7-12%) in single-level lumbar instrumentation.
• The stiffness benefit increases with the extensiveness of spinal decompression.
• CL augmentation may be reserved for highly unstable segments rather than routine use in standard spinal fusion and decompression.