Disc degeneration affects the multidirectional flexibility of the lumbar spine.

Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut.
Spine (Impact Factor: 2.45). 07/1994; 19(12):1371-80. DOI: 10.1097/00007632-199406000-00011
Source: PubMed

ABSTRACT An in vitro biomechanical investigation using human lumbar cadaveric spine specimens was undertaken to determine any relationship between intervertebral disc degeneration and nonlinear multidirectional spinal flexibility.
Previous clinical and biomechanical studies have not established conclusively such a relationship.
Forty-seven discs from 12 whole lumbar spine specimens were studied under the application of flexion-extension, axial rotation, and lateral bending pure moments. Three flexibility parameters were defined (neutral zone (NZ), range of motion (ROM), and neutral zone ratio (NZR = NZ/ROM)) and correlated with the macroscopic and radiographic degeneration.
In flexion-extension, the ROM decreased and NZR increased with degeneration. In axial rotation, NZ and NZR increased with degeneration. In lateral bending, the ROM significantly decreased and the NZR increased with degeneration. In all three loading directions, the NZR increased, indicating greater joint laxity with degeneration.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective Osteoporotic Fractures in Men (Hong Kong) and Osteoporotic Fractures in Women (Hong Kong) represent the first large-scale prospective population-based studies on bone health in elderly (age ≥65 years) Chinese men (n = 2,000) and women (n = 2,000). We undertook the current study to investigate the prevalence of lumbar disc space narrowing in these subjects, and to identify the potential relationship between disc space narrowing and sex, bone mineral density (BMD), and other demographic and clinical data. Methods On lumbar lateral radiographs, L1/L2–L4/L5 disc space was classified into 4 categories: 0 = normal; 1 = mild narrowing; 2 = moderate narrowing; 3 = severe narrowing. We compared demographic and clinical data between subjects with and those without total disc space narrowing scores ≥3. ResultsDisc space narrowing was more common in elderly women than in elderly men. The mean ± SD disc space narrowing score for the 4 discs was 2.71 ± 2.21 for men and 3.08 ± 2.50 for women (P < 0.0001). For the 3 age groups of 65–69 years, 70–79 years, and ≥80 years, the average disc space narrowing score increased with increasing age in both men and women, and to a greater degree in women than in men. The average disc space narrowing score differences between women and men were 0.12, 0.40, and 0.90, respectively, in the 3 age groups. For both men and women, a disc space narrowing score ≥3 was associated with older age, higher spine and hip BMD, low back pain, and restricted leg mobility. Conclusion The prevalence and severity of disc space narrowing are higher in elderly women than in elderly men. With increasing age, disc space narrowing progresses at a greater rate in women than in men. A disc space narrowing score ≥3 is associated with higher spine and hip BMD.
    Arthritis & Rheumatology 04/2013; 65(4). · 7.48 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This review will acquaint the reader with normal development, structure, and function of the intervertebral disc. The disc is composed of the vertebral endplate, nucleus pulposus, and annulus fibrosus. These three functional components all serve important purposes for health and function of the disc. Nutrition and biomechanics are also discussed. The molecular basis of disc degeneration is reviewed so that biologic approaches to the reversal and or treatment of disc degeneration may be better understood.
    The Spine Journal 11/2004; 4(6 Suppl):158S-166S. · 2.80 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The goal of the current study was to investigate potential differences in back and hip extensor muscle activity and hip extension force during prone hip extension (PHE) in individuals with lumbar segmental instability (LSI) and asymptomatic subjects. Thirty-six subjects with LSI and 26 asymptomatic volunteers participated in this study. Muscle activity of the erector spinae, gluteus maximus, and biceps femoris was recorded using electromyography (EMG), and hip extension force was measured by a digital force gauge. Muscle activity was significantly greater in subjects with LSI than in asymptomatic subjects during PHE (p < 0.05). Hip extension force was significantly lower in the subjects with LSI than in asymptomatic subjects during PHE (p < 0.05). These findings suggest that during PHE, subjects with LSI have differences in back and hip extensor muscle activity and hip extension force compared to asymptomatic individuals.
    Manual Therapy 11/2014; · 1.76 Impact Factor