Spinal cord stimulation in sympathetically maintained complex regional pain syndrome type I with severe disability. A prospective clinical study

In this prospective trial we assessed the long-term effect of spinal cord stimulation (SCS) on the improvement of functional status in complex regional pain syndrome type I (CRPS I). A prerequisite for eligibility to SCS treatment was the responsiveness of patients to sympathetic nerve block. In 29 patients with chronic sympathetically maintained CRPS I, the efficacy of SCS on deep pain, allodynia and functional disability was determined. Pain intensity was estimated during SCS free intervals of 45 min (inactivation test) every 3 months and compared with that under SCS treatment. On SCS treatment, both deep pain and allodynia could be permanently reduced from 10 to 0–2 on a 10 cm visual analogue scale (VAS) ( p < 0.01). During the inactivation tests, reoccurrence of pain up to 8 VAS (quartiles 6–8) was measured. Considerable impairments in daily living activities, objectified by the pain disability index, were also restored ( p < 0.01). After a follow-up period of 35.6 ± 21 months, 12 of 16 patients with affected upper limb showed significant increase of the fist grip strength from 0 to 0.35 (quartiles 0.1–0.5) kg compared with 0.9 (quartiles 0.7–1.1) kg on the unaffected side ( p < 0.01). Eight of ten patients with lower limb disability resumed walking without crutches. Previous pain medication could be significantly reduced ( p < 0.01). As a result of permanent pain relief under long-term SCS combined with physiotherapy, the functional status and the quality of life could be significantly improved in sympathetically maintained CRPS I.