Lumbar arachnoiditis: Does imaging associate with clinical features?

Lumbar arachnoiditis is a rare and debilitating neurologic disorder with multiple etiologies and a spectrum of imaging and clinical characteristics. Prior reports have anecdotally claimed that no association exists between findings of arachnoiditis observed on magnetic resonance imaging (MRI) and those assessed clinically. The purpose of this study was to determine if MRI features of lumbar arachnoiditis associate with the clinical findings of the disorder.

Twenty eight patients with lumbar arachnoiditis reported on MRI between 2012 and 2018 were retrospectively identified. A variety of MRI and clinical features of lumbar arachnoiditis were cataloged for these patients based on common findings discovered through literature review. Imaging findings included cauda equina nerve root contour and thickening, adhesion location, level of involvement, enhancement, and Delamarter group. Clinical findings included demographics, etiology, symptom dynamics, and signs/symptoms. Fisher's exact tests were used to determine associations between the imaging and clinical features of lumbar arachnoiditis.

In general, MRI findings did not associate with the clinical features of lumbar arachnoiditis with a few exceptions. Most notably, confounding lumbar pathology was associated with symptom dynamics (p = 0.004) and nerve root contour was associated with motor and sensory symptoms (p = 0.01). The suspected arachnoiditis etiology of the majority of patients was either post-operative or post-infectious in nature.

MRI findings in lumbar arachnoiditis offer limited insight into the clinical presentation of the disorder.