Intrathecal Baclofen Dosage for Long-Term Treatment of Patients With Spasticity Due to Traumatic Spinal Cord Injuries or Multiple Sclerosis

OBJECTIVE: To investigate dosage changes in intrathecal baclofen during long-term treatment of patients with severe leg spasticity. METHODS: We performed a retrospective chart review of 49 patients treated with an intrathecal baclofen pump (ITB) because of severe leg spasticity, for a minimum of 7 years. Eight patients were excluded due to catheter/pump failure or factors aggravating spasticity. Of the remaining 41 patients, 19 had spinal cord injury (SCI) and 22 were diagnosed with multiple sclerosis (MS). Among the SCI patients, 15 had cervical and 4 thoracic SCI, with 7 patients showing the American Spinal Injury Association impairment scale (AIS) A and 12 patients with AIS B–D. The dose was regulated by discussion among the patients and their physicians, usually 4–10 times annually, to reduce leg spasticity and also avoid leg/trunk weakness. RESULTS: After 1 year patients on ITB needed a median dose of 168 mg/24 hr (range, 30–725 mg) for an optimal effect. After 7 to 10 years the dosage needed to reduce leg spasticity in the MS patients was significantly increased compared with the initial dose (mean 157%, n=22 and mean 194%, n=18). In contrast, the SCI patients needed only a modest increase (mean 113% and 121%). The difference between MS and SCI patients was significant (t-test p=0.006 and p=0.004). CONCLUSION: The increased dosage in MS patients compared with patients diagnosed with SCI probably reflects the progressive disease course. The need for a large dosage increase in patients with SCI suggests possible pump failure, triggering factors for spasticity or progressive spinal disease.