Quantitative Relationship between the Degree of Lumbar Disc Degeneration and Intervertebral Disc Height in Patients with Low Back Pain

The aim of this study is to study the relationship between the degree of lumbar disc degeneration and the height of the disc in patients with pain in the lower back and determine whether there is a dose-response relationship between the two. Eighty-five patients were examined by magnetic resonance imaging (MRI). The grade of lumbar degeneration was determined by the Pfirrmann grading system, and the intervertebral height and VAS pain scores were measured. The height difference of intervertebral discs with different degeneration levels was measured by the F test. This difference was correlated and further quantified by regression analysis. Finally, the differences intervertebral disc heights with a VAS score of 0–6 and 7–10 were observed by an independent sample t-test. The higher degree of disc degeneration in each lumbosacral segment, the lower the intervertebral disc height (p ≤ 0.011). When discs with grade 1 and grade 5 degeneration were excluded, the results remained the same (p ≤ 0.034). To quantify correlations, at each lumbar level, the disc height was reduced for each level of lumbosacral disc degeneration, and the height of disc was reduced after adjusting according to age, sex, and BMI (β range: −1.25 mm to −1.76 mm, 95% CI: −0.83 to −2.29, all p ≤ 0.002). Subjects with a VAS score of 7–10 had a lower intervertebral disc height than those with a VAS score of 0–6, especially with respect to total height levels at L4/5, L5/S1, and L1-S1 (p ≤ 0.04). This study showed a relationship between increased degree of intervertebral disc degeneration and decreased the disc height in patients with pain in the low back. Although the assessment of lumbar and lumbosacral level disc degeneration involves many qualitative measurements, these statistical data confirm the effectiveness of lumbosacral disc height as a continuous data measure and quantification in clinical trials and epidemiological studies.