Electrical spinal cord stimulation in the long-term treatment of chronic painful diabetic neuropathy.

AIMS: Electrical spinal cord stimulation (ESCS) is a technique for the management of chronic painful diabetic neuropathy (CPDN) affecting the lower limbs. We assessed the efficacy and complication rate of ESCS implanted at least 7 years previously in eight patients.

METHODS: After a trial period of percutaneous stimulation, eight male patients had been implanted with a permanent system. Mean age at implantation was 53.5 years and all patients were insulin treated with stage 3 severe disabling CPDN of at least 1 year's duration. The ESCS was removed from one patient at 4 months because of system failure and one patient died 2 months after implantation from a myocardial infarction.

RESULTS: Six patients were reviewed a mean of 3.3 years post-implantation. With the stimulator off, McGill pain questionnaire (MPQ) scores (a measure of the quality and severity of pain) were similar to MPQ scores prior to ESCS insertion. Pain scores (visual analogue scale) were measured with the stimulator off and on, respectively: background pain [74.5 (63-79) mm vs. 25 (17-33) mm, median (interquartile range), P = 0.03), peak pain (85 (80-92) mm vs. 19 (11-47) mm, P = 0.03]. There were two further cardiovascular deaths (these patients had continued pain relief) and the four surviving patients were reassessed at 7.5 (range 7-8.5) years: background pain [73 (65-77) mm vs. 33 (28-36) mm, median (interquartile range)], peak pain [86 (81-94) mm vs. 42 (31-53) mm]. Late complications (> 6 months post-insertion) occurred in two patients; electrode damage secondary to trauma requiring replacement (n = 1), and skin peeling under the transmitter site (n = 1). One patient had a second electrode implanted in the cervical region which relieved typical neuropathic hand pains.

CONCLUSIONS: ESCS can continue to provide significant pain relief over a prolonged period of time with little associated morbidity.