Single level lumbar laminectomy alters segmental biomechanical behavior without affecting adjacent segments

Area of Science:

• Orthopedic surgery
• Spinal biomechanics
• Degenerative spine disease

Background:

• Degenerative lumbar spinal stenosis causes neurological symptoms via neural compression.
• Lumbar laminectomy is a common treatment for symptomatic degenerative spinal stenosis.
• The impact of single-level laminectomy on spinal motion and stiffness is not well understood.

Purpose of the Study:

• To determine the effect of single-level lumbar laminectomy on the range of motion and stiffness of treated and adjacent spinal segments.
• To investigate potential predictors of post-operative spondylolisthesis or spinal failure.

Main Methods:

• Twelve cadaveric human lumbar spines were tested for range of motion and stiffness before and after single-level laminectomy.
• Spines underwent testing in flexion-extension, lateral bending, and axial rotation.
• Repeated measures analysis of variance was used to analyze the effects on treated, adjacent, and control segments.

Main Results:

• Range of motion significantly increased at the laminectomy level (flexion-extension: 7.3%, lateral bending: 7.5%, axial rotation: 12.2%).
• Adjacent segments showed a significant decrease in range of motion only in lateral bending (-7.7%).
• Spinal stiffness was not significantly affected by the laminectomy procedure.

Conclusions:

• The observed 7-12% increase in lumbar spine range of motion after single-level laminectomy does not necessitate routine spinal instrumentation.
• If instrumentation is used, it should primarily focus on stabilizing the directly treated spinal segment.
• Further research may explore the long-term implications of altered spinal biomechanics post-laminectomy.