Does autonomic neuropathy influence spinal cord stimulation therapy success in diabetic patients with critical lower limb ischemia?

BACKGROUND: Spinal cord stimulation (SCS) improves microcirculatory blood flow and relieves diabetic neuropathic and ischemic pain, reducing the amputation rate in patients with peripheral arterial occlusive disease (PAOD). The purpose of this study was to evaluate whether the presence of autonomic neuropathy in diabetic patients with PAOD influences the success of SCS therapy.

METHODS: Sixty consecutive diabetic patients (15 with early and 13 with definite and/or combined autonomic neuropathy) with an ankle/brachial systolic pressure index (ABI) less than 0.20 +/- 0.08, underwent spinal cord stimulation after failed conservative or surgical treatment. The neuropathic status of the patients was evaluated before implantation and pedal TcpO2 measurements on the dorsum of the foot were performed.

RESULTS: Limb salvage and pain relief >75%, evaluated with the visual analogue scale, were achieved in 35 patients, whereas in 12 a partial success with pain relief >50% and limb salvage for at least 6 months were obtained. In 13 patients the method failed and the ischemic limbs were amputated. Among the 28 diabetic patients with autonomic neuropathy the treatment failed or resulted in only partial success in 25, whereas in all 32 patients without neuropathy limb salvage and pain relief >75% were achieved (p < 0.0001). Partial success in 10 patients with early neuropathy and in two with definite was achieved (p = 0.008), whereas in 11 patients with definite neuropathy and in two with early the method failed (p < 0.001). The stage of the neuropathy was inversely related to the success of SCS therapy, independent of the stage of the disease. The method's success was related to the presence of adequate paraesthesias and warm feeling in the painful area with size reduction of the trophic lesions.

CONCLUSIONS: Diabetic patients with peripheral arterial occlusive disease presenting with intractable pain may be successfully treated with spinal cord stimulation unless they have associated severe autonomic neuropathy.