New Option for Refractory, Painful, Diabetic Polyneuropathy
Source: Tesfaye S, et al. Lancet 1996;348:1698-1701.
Current medical therapy for painful diabetic neuropathy includes tricyclic antidepressants, anticonvulsants, nonsteroidal anti-inflammatory agents, and narcotic analgesics. Renal toxicity and a high potential for abuse, respectively, limit the usefulness of the latter two classes of agents, whereas success with the former two is elusive in up to 25% of patients (Max MB, et al. N Engl J Med 1992;326:1250-1256). Thus, reports of success dealing with this painful problem using new measures are always welcome.
Ten diabetic patients with painful peripheral neuropathy refractory to conventional treatment underwent epidural electrode implantation into the thoracic/lumbar region to study the efficacy of spinal cord stimulation in the relief of neuropathic pain. Using an active stimulator, eight patients experienced a greater than 50% reduction in pain, measured by visual analog score, and were converted to a permanent system. Of these, one died of unrelated causes two months later. All remaining seven patients obtained significant relief of both background and peak pain at three months, and six continued to benefit at six and 14 months. McGill pain questionnaire scores with the stimulator turned off at study end were unchanged from baseline, indicating that improvement of the underlying condition had not occurred. With the stimulator turned on at study end, scores were significantly improved from baseline (P < 0.05), and six patients were using the stimulator exclusively for pain relief. Interestingly, exercise tolerance improved significantly in parallel with pain relief. Complications included wound infection following implantation in two.
Comment by Michael Rubin, MD
Though invasive, epidural spinal cord stimulation (ESCS) is safe and effective for otherwise stubborn cases of painful diabetic neuropathy, the most common form seen in the United States. Monotherapy and polypharmacy should be attempted first, but if found wanting, there should be no hesitation in recommending ESCS to patients debilitated by this condition.
Dr. Rubin is Associate Professor of Clinical Neurology, New York Hospital-Cornell Medical Center