Successful treatment of central pain in a multiple sclerosis patient with epidural stimulation of the dorsal root entry zone.

OBJECTIVE: We report a case of central pain successfully treated by epidural placement of spinal cord stimulator electrodes. Neuromodulation of primary afferent fibers and the underlying dorsal root entry zone provided effective analgesia whereas traditional lead placement over the dorsal columns on a prior occasion had not been effective. The rationale for this technique based on current understanding of the mechanisms of central pain and the risk/benefit considerations are discussed. CASE REPORT: A 52-year-old woman presented with a 2-year history of pain in the lateral hand secondary to a demyelinating episode in the C2-4 spinal cord secondary to multiple sclerosis. Medications, sympathetic blocks, and acupuncture had been ineffective. One year after an unsuccessful single-lead trial of spinal cord stimulation over the cervical dorsal columns, a dual-lead trial of spinal cord stimulation over the lateral cervical spinal cord and dorsal roots provided significant analgesia, prompting a successful permanent implant. OUTCOME MEASURES: Responses on the Brief Pain Inventory short form and quantitative thermosensory testing data were collected at two timepoints 16 days apart under two conditions: no stimulation and single-lead stimulation of cervical primary afferents and underlying spinal cord.
RESULTS: The patient's questionnaire responses indicated significantly improved pain scores with lateral-lead neuromodulation that was associated with a reduction in her baseline heat hypoalgesia.
CONCLUSIONS: Lateral-lead spinal cord stimulation may be effective for some central pain syndromes through a partial restoration of homeostatic small-fiber signaling. Neuroanatomical and physiological data in a larger population of patients will be required to predict the best responders to this therapeutic modality.