Magnetic resonance imaging findings as predictors of clinical outcome in patients with sciatica receiving active conservative treatment.

Objective: The aims of this study were to investigate the possible prognostic value of disk-related magnetic resonance imaging (MRI) findings in relation to recovery at 14 months in patients with severe sciatica, and whether improvement of disk herniation and/or nerve root compromise is concurrent with recovery.

Methods: All patients included in this prospective observational study of patients with sciatica receiving active conservative treatment were scanned at baseline and at 14 months' follow-up. Definite recovery at follow-up was defined as an absence of sciatic leg pain and a Roland Morris disability score of 3 or less. Potential predictors of interest were disk-related MRI findings in the lumbar spine. Bi- and multivariate logistic regression analyses were used to identify any predictors of recovery. Age, sex, and treatment were included in the analyses as possible confounding/modifying factors.

Results: According to the definitions used, 53% of 154 patients recovered; 63% of men (n = 84) and 40% of women (n = 70). In the multivariate analyses, broad-based protrusions, extrusions, and male sex were found to be predictive of a positive outcome. Sex was identified as a true confounder in that the prevalence of disk-related MRI findings was different for men and women, and they had different recovery rates. Improvement of disk herniations and nerve root compromise over time did not coincide with definite recovery.

Conclusions: In patients with sciatica receiving active conservative treatment, broad-based protrusions and extrusions at baseline were positive predictors of definite recovery at 14 months. However, at 14 months the MRI-defined improvement of disk herniations and nerve root compromise was not correlated with definite recovery.