Repetitive transcranial magnetic stimulation accuracy as a spinal cord stimulation outcome predictor in patients with neuropathic pain.

OBJECT: Spinal cord stimulation (SCS) is an effective albeit invasive and relatively expensive treatment of neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) is a non-invasive treatment of neuropathic pain. The aim of the current study was to investigate whether rTMS can predict the successful outcome of SCS.

METHODS: The study population consisted of 22 patients with neuropathic pain who had undergone SCS and rTMS. We conducted statistical analyses to identify the factors that predict pain reduction following SCS.

RESULTS: Multiple regression analyses showed that only degree of pain relief following rTMS was statistically correlated with success in SCS; on the other hand, age, sex, lesion location, pain duration and laterality, and targeted extremities were not correlated. Using receiver-operating characteristic (ROC) curve analyses of the pain relief following rTMS, the diagnostic sensitivity for successful SCS was 0.60 and the specificity was 0.83.

CONCLUSIONS: The degree of pain relief following rTMS over M1 is a significant prognostic factor of SCS outcome in patients with intractable neuropathic pain.

SIGNIFICANCE: The current study provides evidence showing that rTMS, a non-invasive and relatively easy to administer procedure, may aid in the selection of suitable candidates for SCS treatment.