Intrathecal baclofen for dystonia of complex regional pain syndrome

• Published in: Pain (Amsterdam) Vol. 143; no. 1; pp. 41 - 47
• Main Authors: Rijn, M.A. van, Munts, A.G., Marinus, J., Voormolen, J.H.C., de Boer, K.S., Teepe-Twiss, I.M., van Dasselaar, N.T., Delhaas, E.M., van Hilten, J.J.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Elsevier B.V 01.05.2009; Elsevier
• Subjects: Adult; Baclofen; Baclofen - administration & dosage; Baclofen - adverse effects; Biological and medical sciences; Complex regional pain syndrome; Complex Regional Pain Syndromes - drug therapy; Diseases of striated muscles. Neuromuscular diseases; Dose-Response Relationship, Drug; Dystonia; Dystonia - drug therapy; Female; Fundamental and applied biological sciences. Psychology; Humans; Illness and personality; Illness, stress and coping; Injections, Spinal; Intrathecal; Male; Medical sciences; Muscle Relaxants, Central - administration & dosage; Neurology; Psychology and medicine; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Single-Blind Method; Treatment Outcome; TREND study; TREND study; Dystonia; Complex regional pain syndrome; Intrathecal; Baclofen; Human; Nervous system diseases; Long term; Involuntary movement; Cerebral disorder; Quality of life; Disability; Striated muscle disease; Improvement; Pain; Treatment; Central nervous system disease; Placebo; Safety; Neurological disorder; Extrapyramidal syndrome
• ISSN: 0304-3959; 1872-6623
• DOI: 10.1016/j.pain.2009.01.014

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 μg/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.