Relationship Between Pelvic Tilt and Lumbar Disc Degeneration

ABSTRACT

STUDY DESIGN: Retrospective analysis. OBJECTIVES: To determine the relationship between pelvic tilt and lumbar disc degeneration. SUMMARY OF LITERATURE REVIEW The shape and the spatial orientation of the pelvis determine the organization of the lumbothoracic spine. The purpose of our study was to determine the relationship between pelvic tilt and lumbar disc degeneration. MATERIALS AND METHODS: Sixty patients over 50 years of age who had undergone lumbar spine magnetic resonance imaging were recruited. In individuals between 41 and 60 years of age, the normal pelvic tilt is 14°. Patients were divided into a low pelvic tilt (PT) group (<14°) and a high pelvic tilt (PT) group (≥14°). Lumbar disc degeneration was graded from I to V according to the Pfirrmann grade. We defined grades IV and V as high-grade degeneration and the others as low-grade degeneration. Radiologic parameters and lumbar disc degeneration were compared between these 2 groups. RESULTS: In the low PT group, the average degeneration grade of each lumbar segment was 2.61 in L1-L2, 2.61 in L2-L3, 3.00 in L3-L4, 3.39 in L4-L5, and 3.84 in L5-S1. The corresponding grades in the high PT group were 2.34 in L1-L2, 2.62 in L2-L3, 3.07 in L3-L4, 3.76 in L4-L5, and 3.55 in L5-S1. The grade of degeneration of the high PT group was significantly higher than that of the low PT group for L4-L5 (p=0.031). High-grade degeneration of the L4-L5 segment was significantly more common in the high PT group (odds ratio=4.65; 95% CI, 1.406-15.381; p=0.012). CONCLUSIONS: Patients with high pelvic tilt had a higher grade of lumbar disc degeneration in the L4-L5 segment regardless of age or gender.