The Association of Lumbosacral Sagittal Alignments and the Patterns of Lumbar Disc Degeneration

ABSTRACT

STUDY DESIGN: Retrospective review and radiological analysis. OBJECTIVES: We investigated whether the lumbosacral sagittal curvature have any relation to the patterns of lumbar disc degeneration. SUMMARY OF THE LITERATURE REVIEW Recently, there have been many studies on the correlations between the changes of lumbar disc degeneration and associated factors, such as age, gender, weight, occupation, cigarette smoking, and genetics; but, it is hard to find research into lumbosacral sagittal alignments. MATERIALS AND METHODS: This study enrolled 117 young adult patients limited by age (18-35 years), BMD (<30kg/m2), no smoking, occupation except heavy worker, no prior lumbar surgery and no combined spinal deformity. By measuring the pelvic incidence, sacral slope, lumbar tilt angle, lumbar lordosis and lumbar axis indicating the parameters of sagittal alignments, we investigated the correlation between the number and severity of lumbar disc degeneration and the number of herniated intervertebral discs. RESULTS: This study found a moderate correlation between pelvic incidence, sacral slope, lumbar lordosis, and the number of lumbardegenerative disc (r=-0.451, p<0.001; r=-0.433, p<0.001; r=-0.425, p<0.001). We calculated the most proper cut-off value of pelvic incidence associated with more than three segments of multiple lumbar disc degeneration, using a minimum p-value approach. CONCLUSIONS: As pelvic incidence, sacral slope, and lumbar lordosis indicating the parameters of lumbosacral sagittal alignments get smaller, the numbers of lumbar disc degenerations and herniated intervertebral discs increase. When pelvic incidence is below 45.6 degrees, it is more likely for degenerative changes of lumbar disc to affect more than three segments.