Spinal cord stimulation with sympathetically independent pain and sympathetically maintained pain

ABSTRACT

BACKGROUND: Complex regional pain syndrome (CRPS) is categorized into sympathetically maintained pain (SMP) and sympathetically independent pain (SIP). Spinal cord stimulation (SCS) is a promising approach in the treatment of severely disabling CRPS. Patients with good responses to sympathetic block before SCS are more likely to have positive responses to SCS than those with negative responses. This study compared the effects of SCS in patients with CRPS, of SMP and SIP categories. METHODS: This was a retrospective study of 16 patients (SMP 8, SIP 8) with CRPS who had undergone trials of SCS. Eleven of the patients had permanent SCS device implants, and the pain relief levels at 1 and 6 months were recorded. RESULTS: Sixteen patients with severe, incapacitating, and therapy-resistant CRPS underwent SCS trials. Five patients (SMP 3, SIP 2) had poor pain relief during the trial despite adequate coverage. The remaining 11 patients (SMP 5, SIP 6) had permanent electrode implantation performed under local anesthesia and experienced good pain relief. The difference in VAS reduction was not significant between the two groups at the 1-month follow-up (P = 0.325) and the 6-month follow-up (P = 0.779). CONCLUSIONS: There were no statistically significant differences in VAS pain scores between the two groups. The favorable outcome in all 11 patients with only minor remaining symptoms or without remaining symptoms or severe recurrences suggests that SCS is an efficient treatment in SMP and SIP.