Critical spinal cord lesions associate with secondary progressive motor impairment in long-standing MS: A population-based case-control study.

BACKGROUND

Progressive motor impairment anatomically attributable to prominent, focally atrophic lateral column spinal cord lesions ("critical lesions") can be seen in multiple sclerosis (MS), for example, progressive hemiparetic MS.

OBJECTIVE

The aim of this study was to investigate whether similar spinal cord lesions are more frequent in long-standing MS patients with secondary progressive motor impairment (secondary progressive MS (SPMS)) versus those maintaining a relapsing-remitting course (relapsing-remitting MS (RRMS)).

METHODS

We retrospectively identified Olmsted County (MN, USA) residents on 31 December 2011 with (1) RRMS or SPMS for ⩾25 years, and (2) available brain and spine magnetic resonance imaging (MRI). A blinded neuroradiologist determined demyelinating lesion burden and presence of potential critical lesions (prominent focally atrophic spinal cord lateral column lesions).

RESULTS

In total, 32 patients were included: RRMS, 18; SPMS, 14. Median (range) disease duration (34 (27-53) vs. 39 (29-47) years) and relapse number (4 (1-10) vs. 3 (1-15)) were similar. In comparison to RRMS, SPMS patients more commonly showed potential critical spinal cord lesions (8/18 (44%) vs. 14/14 (100%)), higher spinal cord (median (range) 4 (1-7) vs. 7.5 (3-12)), and brain infratentorial (median (range) 1 (0-12) vs. 2.5 (1-13)) lesion number;  < 0.05. By multivariate analysis, only the presence of potential critical lesions independently associated with motor progression ( = 0.02).

CONCLUSION

Critical spinal cord lesions may be important contributors to motor progression in MS.