Intervertebral disc degeneration: New insights based on “skipped” level disc pathology

Abstract

Objective. Typically, age and abnormal physical loading ("wear and tear") have been associated with the development of intervertebral disc degeneration. In the past decade, various additional etiologic factors for disc degeneration have been sporadically reported in the literature; however, many investigators continue to place tremendous emphasis on the effects of age and biomechanics associated with disc degeneration. The aim of this study was to provide additional insight into the notion that age and biomechanics are key factors in the development of disc degeneration. To this end, we addressed the prevalence of and risk factors associated with a unique pattern of disc degeneration of the lumbar spine, "skipped" level (nonconsecutive) disc degeneration (SLDD).Methods. As part of a large genetics-based study in southern Chinese individuals (n ‫؍‬ 1,989), a crosssectional analysis was performed in subjects exhibiting disc degeneration in >2 levels (n ‫؍‬ 838) who were then categorized as having SLDD (n ‫؍‬ 174) or non-SLDD (contiguous, multilevel; n ‫؍‬ 664). Various radiographic parameters were assessed based on T2-weighted magnetic resonance imaging (MRI). Subject demographics were assessed, and univariate and multivariate logistic regression analyses were performed.Results. Overall, 8.7% of the whole population (n ‫؍‬ 1,989) had SLDD, while it was present in 20.8% of subjects with multilevel disc degeneration (n ‫؍‬ 838). SLDD was more prevalent in male subjects (adjusted odds ratio [OR] 1.48, 95% confidence interval [95% CI] 1.04-2.10, P ‫؍‬ 0.028). SLDD was significantly associated with the presence of Schmorl's nodes (adjusted OR 2.72, 95% CI 1.78-4.15, P < 0.001), which also presented in levels with no disc degeneration. A history of disc bulge/extrusion (P ‫؍‬ 0.004) and/or a history of back injury (P ‫؍‬ 0.010) was significantly associated with non-SLDD, and a greater degree of overall severity of disc degeneration was also associated with non-SLDD. Other demographic and MRI findings did not significantly differ between groups.Conclusion. To our knowledge, this report is the first to describe the prevalence and risk factors associated with SLDD. Our study challenges the paradigm that age and biomechanics are the key factors associated with the development of disc degeneration. Although age and biomechanical factors may play a role in the manifestation of disc degeneration, our novel findings of SLDD patterns provide further awareness of and support for the notion that additional etiologic factors may play a role in the development of disc degeneration. Such factors warrant further investigation to shed light on the cause of disc degeneration.

Gender differences after lumbar sequestrectomy: a prospective clinical trial using quantitative sensory testing

“…These dissimilarities on the other hand are due to hormonal differences and the onset of menstruation-related pain in women [36]. Nevertheless, disc degeneration is multifaceted, traditionally attributed to age, mechanical loading, gender, trauma, obesity and other factors impairing disc nutrition [37][38][39][40][41].…”

Non-contiguous post-traumatic double-level lumbar disc prolapse presenting with acute monoparesis

“…Recently, in the Hong Kong Degenerative Disc Disease Cohort study, which is a population-based study of Southern Chinese patients primarily assessing the phenotype of disc degeneration, Cheung et al [3] in their analysis of 1989 subjects, found a prevalence of 8.1 % and 20 % for SLDD in the overall population and among individuals with multilevel disc degeneration, respectively.…”

“…The concept of adjacent-level disc degeneration is best noted in spinal fusion cases in which adjacent-level disc changes manifest or are accelerated proximal to an immobile fused segment and taper off as segments become more distal [9-11]. Although single-disc pathology is common, the phenomenon of SLDD is truly unique and is not completely understood [3].…”

“…In 1992, Hsu et al 31 observed the unique occurrence of skip (non-contiguous) level degeneration (SLDD) of the lumbar spine [2]. This was further studied in 2010 and seemed to be underreported [3].…”

Are “Patterns” of Lumbar Disc Degeneration Associated With Low Back Pain?

“…The unique occurrence of noncontiguous or skipped levels of disc degeneration (SLDD) of the lumbar spine, with healthy/normal discs between degenerated discs on magnetic resonance imaging (MRI), has been previously reported. 31 Recently, in the Hong Kong Degenerative Disc Disease Cohort study, which is a population-based study of Southern Chinese patients primarily assessing the phenotype of disc degeneration, Cheung et al , 32 in their analysis of 1989 subjects, found a prevalence of 8.1% and 20% for SLDD in the overall population and among individuals with multilevel disc degeneration, respectively.…”