Spinal Column Phenotypes with Lumbar Developmental Spinal Stenosis: Results from 2,387 Magnetic Resonance Imaging

Abstract

Purpose: Lumbar developmental spinal stenosis (DSS) is an imaging phenotype appearing as a shortened anteroposterior (AP) vertebral canal diameter at multiple levels. It is likely a result of maldevelopment of the spinal canal. The relationship of canal narrowing with other radiological parameters in the spinal column is unknown. Methods: This was a radiological analysis of 2,387 subjects who underwent L1–S1 magnetic resonance imaging (MRI). Means and ranges were calculated for their age, gender, body mass index, and MRI measurements. AP vertebral canal diameters were utilized to differentiate cases of DSS from controls. Other imaging parameters included the vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U-test and chi-square test were conducted to search for measurement differences between cases and controls. To identify possible associations between DSS and MRI parameters, parameters that were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for subject demographics. Results: Axial AP vertebral canal diameter, interpedicular distance, AP dural sac diameter, lamina angle, and sagit-tal mid-vertebral body height were significantly different between cases and controls (all p<0.05). Narrower interpedicular distance and AP dural sac diameter were associated with DSS (odds ratio [OR], 0.506–0.745; p=0.001–0.002). Lamina angle (OR, 1.127; p=0.002) and right facet joint angulation (OR, 0.022; p=0.002) were also associated with DSS. No association was observed between disc parameters and DSS. Conclusions: From this large-scale cohort, the canal size is found to be independent of subject body habitus. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. Besides, there is no relationship between DSS and soft tissue changes of the spinal column, which suggested DSS is a unique result of bony maldevelopment. Findings should be validated in other ethnicities and populations.