How does spinal canal decompression and dorsal stabilization affect segmental mobility? A biomechanical study.

Area of Science:

• Spine biomechanics
• Surgical stability analysis
• Spinal fusion alternatives

Background:

• Lumbar spinal canal decompression may impact segmental stability.
• Optimal resection levels and stabilization needs require further investigation.
• This study examines kinetic changes in surgically treated lumbar motion segments.

Purpose of the Study:

• To investigate the biomechanical effects of lumbar spinal canal decompression on segmental stability.
• To compare the efficacy of rigid and dynamic stabilization systems.
• To analyze kinetic changes in operated and adjacent lumbar segments.

Main Methods:

• Biomechanical examination of nine human lumbar cadaver spines (L1-L5).
• Progressive resection of dorsal elements (lig. flavum, hemilaminectomy, laminectomy, facetectomy).
• Stabilization using rigid (ART) and dynamic (Dynesys) systems.

Main Results:

• Flavectomy and hemilaminectomy showed no significant range of motion (ROM) changes.
• Facet resection increased extension mobility but not flexion or lateral bending.
• Both rigid and dynamic stabilization reduced ROM, with dynamic systems showing more even distribution of compensatory motion in adjacent segments.

Conclusions:

• Monosegmental lumbar decompression does not essentially destabilize the motion segment in vitro.
• Rigid and dynamic stabilization yield similar ROM reduction in the operated segment.
• Stabilization type influences the distribution of compensatory movements in adjacent segments.