Background: The Roland-Morris disability scale (RMS) for disability secondary to low back pain is a validated and popular instrument in clinical practice and research. We have made a simple modification to the questionnaire to increase sensitivity to sciatica (RMS-L) and validated this in patients with lumbar disc prolapse and radiculopathy.
Methods: The original RMS and modified RMS-L were prospectively administered to 203 patients presenting with lumbar radiculopathy and intervertebral disc prolapse demonstrated on MRI. Scores at pre-operative assessment and follow-up at 3 months and 12-24 months were compared against visual analogue scores (VAS) and Short Form 36 generic health domains.
Findings: Correlation between RMS-L and VAS leg pain was significantly greater than between original RMS and VAS leg pain pre-operatively (r = 0.57 vs. 0.17, p < 0.001) and at 3 months follow-up (r = 0.78 vs. 0.49, p < 0.001). Conversely, correlation between RMS and VAS back pain was significantly higher (r = 0.58 vs. 0.15, p < 0.001). Compared with RMS, at pre-operative assessment, RMS-L showed greater correlation with SF-36 physical function (PF; r = -0.57 vs. -0.32, p < 0.001) and bodily pain (r = -0.58 vs. -0.35, p < 0.001). Similarly, the change in PF to 3 months follow-up showed significantly higher correlation with change in RMS-L compared with the change in RMS (r = -0.60 vs. -0.37, p < 0.001). Effect sizes were good for RMS-L (1.19-1.24) but only moderate for RMS (0.69-0.79).
Conclusions: The original and modified RMS can discriminate disability due to low back pain and sciatica, respectively. Separate assessment of these symptoms and their contribution to functional impairment is useful in assessing suitability for surgery and predicting outcome.