The Effect of Single-Segment Unilateral Laminectomy and Facetectomy On Sheep Lumbar Spine Stability: An In Vitro Biomechanical Study

Abstract

Objective: Decompressive spinal procedures (laminectomy, facetectomy) are performed to treat many pathologies including disk hernia, infection, tumor, and trauma. Knowing the level of instability under physiological loading can help the surgeon decide whether additional spinal fusion is required. Therefore, in this study, the biomechanical effects of unilateral and single-segment laminectomy and facetectomy on lumbar spine stability were investigated and we aimed to answer the question of whether these procedures cause lumbar spine instability. Methods: For this study, 72 lumbar spines containing L1-L7 vertebrae were obtained from 3-4 years old female Merino sheep. The spines were classified as the control group, the unilateral single segment laminectomy group, and the unilateral single segment laminectomy + facetectomy group, and followed by biomechanical testing for compression, flexion, extension, and axial rotation. The statistical analyses were performed using IBM SPSS 21.0 (IBM Corp. Released 2012. Armonk) program. The statistical significance level was considered as p0.05). The rotation maximum torque values were different in at least one group from at least one of the other groups (p=0.031). The paired comparisons showed a significant difference in rotation maximum torque values only between the control group and the facetectomy group (p=0.048). Conclusion: When the unilateral single segment laminectomy is combined with facetectomy, instability may occur in the lumbar vertebra against axial rotational forces.