Continuous intrathecal baclofen in spinal cord spasticity. A prospective study.

Continuous intrathecal infusion of the well known antispastic medication baclofen was evaluated in ten consecutive patients. One year after pump implantation the average Ashworth scale for muscle tone decreased, compared with before treatment, 2.32 points (P < 0.0001), reflexes decreased 2.22 points (P < 0.0001) and the spasm score decreased 1.65 points (P < 0.0001). The average dose increased from 92.22 to 290.95 micrograms (P < 0.0001) between the 1st month of treatment and 1 yr of treatment. The dosage for all patients more than doubled (P < 0.0022) between 3 months and 1 yr postimplantation. There was no significant difference for muscle tone, reflexes or spasms at 3 months v 1 yr. Complications were not unusual and included temporary atelectasis, orthostatic hypotension with escalation of baclofen dose, loss of penile erections, postsurgical pseudo-meningoceles, catheter disruptions and exhausted pump reservoirs. One patient suffered a seizure apparently related to a rapid withdrawal from intrathecal baclofen as a result of catheter sequestration. All patients required a period of intensive inpatient rehabilitation to benefit functionally from the decreased motor tone and/or increased voluntary motor control. The procedure is expensive and close follow-up is necessary for assessing efficacy and refilling the pump. Intrathecal baclofen infusion by subcutaneous pump is useful in treating the effects of spinal spasticity resistant to oral medications. However, there appears to be accommodation to intrathecal baclofen necessitating escalating doses to maintain clinical effects.