Are patterns of lumbar disc degeneration associated with low back pain? New insights based on skipped level disc pathology

Abstract

INTRODUCTION: The occurrence of SLDD of the lumbar spine has recently been noted. To date, patterns of disc degeneration have been overlooked in the association with LBP. The objective of this study was to evaluate the clinical relevance of skipped level disc degeneration (SLDD) to that of contiguous, multilevel lumbar disc degeneration (CMDD) of the lumbar spine. Secondly, the study aimed to identify patterns of SLDD, their classification, prevalence, and clinical relevance. METHODS: A population-based radiographic and clinical study of 3,099 Southern Chinese. Individuals with multilevel lumbar disc degeneration of the lumbar spine on sagittal T2-weighted MRI (N=1,457) were stratified to SLDD (n=301; 20.7%) or CMDD (n=1,156; 79.3%) groups. SLDD was further classified into five types by the relative location of non-degenerated normal disc(s) to degenerated disc levels. Subject demographics, presence of LBP, pain intensity and functional disability were assessed. RESULTS: CMDD increased the likelihood of historical LBP (OR: 1.39; 95% CI: 1.00-1.93; p=0.047) and pain severity (OR: 1.83; 95% CI: 1.23-2.73; p=0.003) in comparison to SLDD. A significant increasing trend of number of levels with disc degeneration, overall disc degeneration severity, and presence of disc bulges/extrusions was noted from SLDD Type I (least severe) to SLDD Type V (most severe) (p<0.05). A higher prevalence of LBP and a higher pain intensity was observed in SLDD classification Type V. Functional disability scores did not differ between CMDD and SLDD nor within SLDD classification-types (p>0.05). DISCUSSION: Our large-scale study is the first to describe novel variants of SLDD-types and their clinical relevance. LBP and severity of pain was more pronounced in individuals with CMDD. Subjects with similar degree but with different patterns of multilevel disc degeneration do differ with respect to low back symptoms. This finding may provide new evidence with regards to the mechanism of LBP.