Spinal cord stimulation in multiple sclerosis: clinical results.

Clinical results of spinal cord stimulation by means of epidural electrodes are reported in 19 patients with multiple sclerosis. On temporary stimulation with percutaneous electrodes, significant improvement in mobility occurred in 27.7% of 18 patients and the same number showed improved sensory function. Only one of 13 patients with severe upper limb ataxia improved. The major response, both in terms of the percentage of patients responding and the extent of the responses seen was in bladder function: 75% of 16 patients with bladder symptoms improved and seven of the 11 patients with severe bladder disturbance (Kurtzke grade 3 or more) improved. Four of these seven patients had before and after cystometry and 3 showed reduced detrusor hyperreflexia. Altogether, 10 patients had a worthwhile clinical response in one or more aspects of the disease and of these, nine have so far gone on to permanent stimulation. Medium-term results (up to two years) show that, with one exception, improvement in bladder function has been maintained as long as stimulation has been continued and at least 50% of improvement in mobility has been maintained. A favourable response depends not upon the fact of stimulation but upon the type of stimulation received. This, along with other evidence, indicates that the response is not caused either by a placebo effect or by the natural fluctuation of the disease.