Relationship of the Pre-operative Condition of Paravertebral Muscle with Post-operative Functional Disability in Patients with Degenerative Lumbar Spinal Disease

ABSTRACT

STUDY DESIGN: A retrospective study on the outcomes of surgical treatment for degenerative lumbar spinal disease. OBJECTIVES: To evaluate the pre-operative paravertebral muscle condition as a predictive factor in patients with degenerative lumbar spinal disease who undergo surgery. SUMMARY OF LITERATURE REVIEW Previous studies have reported that the atrophy of the paravertebral muscle is associated with chronic low back pain. However, few studies have reported on the relationship of the pre-operative paravertebral muscle status with the postoperative functional disability scale. MATERIALS AND METHODS: In this study, we reviewed the history of 20 patients with degenerative lumbar spinal disease treated by decompression and posterior lumbar interbody fusion with posterior instrumentation between 2010 and 2011. The evaluation included the paravertebral muscle volume, fat infiltration on magnetic resonance imaging (MRI), preoperative lumbar lordosis, levels operated on, and the Oswestry Disability Index (ODI). Further, the inter-relationship of the pre-operative paravertebral muscle status, lumbar lordosis, and levels operated on with the post-operative ODI was analyzed. RESULTS: The mean cross-sectional area (CSA) of the paravertebral muscle at the L3-4 and L4-5 levels was 21.9+/-3.4 cm2 and 21.4+/-3.3 cm2, respectively. The mean pre- and post-operative lumbar lordotic angle was 41.0+/-17.5degrees, and 42.3+/-11.1degrees, respectively. The lumbar lordotic angle and the levels operated on were not correlated with the post-operative ODI. However, the CSA of the paravertebral muscle at the L3-4 (r=-0.582, p<0.01) and L4-5 (r=-0.568, p<0.01) levels showed a negative correlation with the post-operative ODI. The levels operated on showed a positive correlation with the post-operative ODI (r=0.420, p<0.01). CONCLUSIONS: The mean CSA of the paravertebral muscle and the levels operated on in patients with degenerative lumbar spinal disease have a significant correlation with the post-operative clinical outcome.