Intrathecal baclofen therapy for stiff-man syndrome and progressive encephalomyelopathy with rigidity and myoclonus.

We report on eight patients with stiff-man syndrome (SMS) or its "plus" variant, progressive encephalomyelopathy with rigidity and myoclonus (PERM) receiving intrathecal baclofen via pump. In six of the patients, follow-ups continued for approximately 2.5 to 6.5 years after pump implantation. Intrathecal baclofen was an effective last-resort alternative for patients who responded poorly to or did not tolerate oral antispasticity medications. General mobility increased, and spasms and rigidity were reduced; however, no complete remissions were observed either before or after pump implantation. PERM patients showed more severe and rapid progression of symptoms and more attacks of autonomic dysregulation than SMS patients. They also required higher doses and more rapid dosage increases. Complications of intrathecal baclofen therapy included spasm-induced rupture of the catheter, catheter dislocation causing radicular symptoms, and pump malfunction resulting in inaccurate dosage administration. Patients suffered fewer side effects with intrathecal baclofen than with oral medication, but overdose resulted in a transient, comalike state in one patient and sudden dosage reduction due to pump failure was fatal in another.