title: Intrathecal baclofen for dystonia of complex regional pain syndrome.
abstract: Dystonia in complex regional pain syndrome (CRPS) responds poorly to treatment. Intrathecal baclofen (ITB) may improve this type of dystonia, but information on its efficacy and safety is limited. A single-blind, placebo-run-in, dose-escalation study was carried out in 42 CRPS patients to evaluate whether dystonia responds to ITB. Thirty-six of the 38 patients, who met the responder criteria received a pump for continuous ITB administration, and were followed up for 12 months to assess long-term efficacy and safety (open-label study). Primary outcome measures were global dystonia severity (both studies) and dystonia-related functional limitations (open-label study). The dose-escalation study showed a dose-effect of baclofen on dystonia severity in 31 patients in doses up to 450 microg/day. One patient did not respond to treatment in the dose-escalation study and three patients dropped out. Thirty-six patients entered the open-label study. Intention-to-treat analysis revealed a substantial improvement in patient and assessor-rated dystonia scores, pain, disability and quality-of-life (Qol) at 12 months. The response in the dose-escalation study did not predict the response to ITB in the open-label study. Eighty-nine adverse events occurred in 26 patients and were related to baclofen (n=19), pump/catheter system defects (n=52), or could not be specified (n=18). The pump was explanted in six patients during the follow-up phase. Dystonia, pain, disability and Qol all improved on ITB and remained efficacious over a period of one year. However, ITB is associated with a high complication rate in this patient group, and methods to improve patient selection and catheter-pump integrity are warranted.
authors.affiliation: Department of Neurology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
authors.forename: M A
authors.initials: MA
authors.lastname: van Rijn
authors.forename: A G
authors.initials: AG
authors.lastname: Munts
authors.forename: J
authors.initials: J
authors.lastname: Marinus
authors.forename: J H C
authors.initials: JH
authors.lastname: Voormolen
authors.forename: K S
authors.initials: KS
authors.lastname: de Boer
authors.forename: I M
authors.initials: IM
authors.lastname: Teepe-Twiss
authors.forename: N T
authors.initials: NT
authors.lastname: van Dasselaar
authors.forename: E M
authors.initials: EM
authors.lastname: Delhaas
authors.forename: J J
authors.initials: JJ
authors.lastname: van Hilten
mesh_terms: D000328:Adult; D001418:Baclofen / Q000008:administration & dosage* / Q000009:adverse effects; D020918:Complex Regional Pain Syndromes / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D004421:Dystonia / Q000188:drug therapy*; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D009125:Muscle Relaxants, Central / Q000008:administration & dosage; D016037:Single-Blind Method; D016896:Treatment Outcome
chemical_list: D009125:Muscle Relaxants, Central; D001418:Baclofen