Intrathecal Baclofen for Severe Spasticity Secondary to Spinal Cord Injury

Abstract

OBJECTIVE: To evaluate the use of intrathecal baclofen for the treatment of muscle spasticity in patients with spinal cord injury. DATA SOURCES: A MEDLINE search was used to identify relevant and pertinent literature. Information was obtained from open-label clinical trials, abstracts, conference proceedings, and review articles. Index terms in the search included baclofen, spasticity, intrathecal drug infusion, spinal cord disease, and neurosurgery. DATA EXTRACTION: Studies were selected for review if they evaluated intrathecal baclofen in patients with spinal cord injury. Emphasis was placed on human studies published in the English language. Trials were reviewed by dosage regimen, therapeutic response, adverse effects, and complications. DATA SYNTHESIS: Thus far, intrathecal baclofen administration shows promise in the treatment of spasticity resulting from spinal cord trauma. Few complications and adverse effects have been reported. CONCLUSIONS: Muscle spasms and spasticity constitute a significant problem in spinal cord injuries, interfering with rehabilitation and leading to inconveniences and complications in these patients. Oral baclofen is the drug of choice for spasticity due to spinal cord trauma. It often is ineffective, however, because of the large dosages required to cross the blood-brain barrier and the subsequent appearance of central nervous system adverse effects. These adverse effects are not tolerated by many patients. Intrathecally administered baclofen has been approved by the Food and Drug Administration (FDA) for the treatment of spasticity in patients with spinal cord injury who are refractory to or cannot tolerate oral baclofen. It is intended for use only in implantable pumps approved by the FDA for the administration of baclofen into the intrathecal space. Intrathecal administration achieves high concentrations in the spinal cord with small dosages, thus reducing the incidence of central nervous system adverse effects. To date, approximately 350 patients with spinal cord injury have been treated with intrathecal baclofen. Reductions in spasticity have been demonstrated in both open-label and placebo-controlled trials. Patients also often make substantial gains in activities of daily living. Few adverse effects and complications have been reported. However, tolerance to the clinical effects of intrathecal baclofen has been reported. Further studies are needed to determine specific patient populations that may benefit most from intrathecal baclofen administration. Individual dosage ranges and follow-up care also need to be defined more completely. In addition, the question of whether tolerance detracts from long-term clinical benefits with intrathecal baclofen needs to be addressed.