ISSLS Prize in Bioengineering Science 2023: Age- and sex-related differences in lumbar intervertebral disc degeneration between patients with chronic low back pain and asymptomatic controls

Abstract

Purpose Clinical management of disc degeneration in patients with chronic low back pain (cLBP) is hampered by the challenge of distinguishing pathologic changes relating to pain from physiologic changes related to aging. The goal of this study was to use imaging biomarkers of disc biochemical composition to distinguish degenerative changes associated with cLBP from normal aging. Methods T1ρ MRI data were acquired from 133 prospectively enrolled subjects for this observational study (80 cLBP, 53 controls; mean ± SD age = 43.9 ± 13.4 years; 61 females, 72 males). The mean T1ρ relaxation time in the nucleus pulposus (NP-T1ρ; n = 650 discs) was used as a quantitative biomarker of disc biochemical composition. Linear regression was used to assess associations between NP-T1ρ and age, sex, spinal level, and study group, and their interactions. Results NP-T1ρ values were lower in cLBP patients than controls (70.8 ± 22.8 vs. 76.4 ± 22.2 ms, p = 0.009). Group differences were largest at L5–S1 (ΔT1ρcLBP-control = −11.3 ms, p < 0.0001), representing biochemical deterioration typically observed over a 9–12 year period (NP-T1ρ declined by 0.8–1.1 ms per year [95% CI]). Group differences were large in younger patients and diminished with age. Finally, the age-dependence of disc degeneration was stronger in controls than cLBP patients. Conclusion Aging effects on the biochemical composition of the L5–S1 disc may involve a relatively uniform set of factors from which many cLBP patients deviate. NP-T1ρ values at L5–S1 may be highly relevant to clinical phenotyping, particularly in younger individuals.

Sex differences in the biomechanical and biochemical responses of caudal rat intervertebral discs to injury

“…Biomechanics analysis of the human spine has shown that female specimens demonstrate a greater overall range of motion in all planes compared to males, regardless of the severity of degeneration 7,14 ; however, this may be due to many factors including differences in spinal anatomy, vertebral anatomy, or tissue laxity. Meanwhile, T1ρ values for the nucleus pulposus (NP) taken from magnetic resonance images of lumbar discs suggest that males may have higher amounts of proteoglycan content than females 15 . Studying sex‐based differences among humans can be difficult due to cultural and gender biases.…”

“…Meanwhile, T1ρ values for the nucleus pulposus (NP) taken from magnetic resonance images of lumbar discs suggest that males may have higher amounts of proteoglycan content than females. 15 Studying sex‐based differences among humans can be difficult due to cultural and gender biases. Research animals, however, live in a controlled environment, allowing for the study of sexual dimorphism while minimizing societal influences.…”