Epidural spinal cord electrical stimulation in diabetic critical lower limb ischemia

Spinal cord stimulation (SCS) has been suggested to improve microcirculatory blood flow to relieve ischemic pain and to reduce amputation rate in patients with peripheral arterial occlusive disease (PAOD). The aim of this study was to evaluate the specific prognostic parameters in the prediction of successful SCS, in diabetic patients, performing a retrospective data analysis. To perform this evaluation, 64 diabetic patients (39 men, 25 women; mean age, 69 years) classified as Fontaine's stage III and IV, with PAOD, were treated with SCS for rest pain and trophic lesions with dry gangrene, after failed conservative or surgical treatment. In clinical controls, pedal transcutaneous oxygen tension (TcPO(2)), ankle/brachial blood pressure index (ABI), and toe pressure Doppler measurements were utilized to select and follow-up the patients. After 58 months of follow-up (range, 20-128 months), pain relief greater than 75% and limb salvage were achieved in 38 diabetic patients. A partial success was obtained in nine patients with pain relief greater than 50% and limb salvage for at least 6 months. The method failed in 17 patients or the device was removed due to technical problems, and the limb was amputated in these patients. TcPO(2) was assessed on the dorsum of the foot. Clinical improvement and SCS success were associated with increase of TcPO(2), before and after implantation. Limb salvage was achieved in the patients who had significant TcPO(2) increase within the 2 weeks of the testing period, independently of the stage of the disease. A TcPO(2) increase of more than 50% in the first 2 months after implantation was predictive of success, and was related to the presence of adequate paresthesias in the painful area during the trial period. TcPO(2) significantly increased after long-term follow-up in all patients with limb salvage (from 22.1 to 43.1 mm Hg in the rest pain patients, from 15.8 to 36.4 mm Hg in those with trophic lesions of less than 3 cm(2), and from 12.1 to 28.1 in those with trophic lesions of greater than 3 cm(2), (p < 0.01). ABI did not changed under stimulation. In diabetic patients with PAOD, the SCS increases the skin blood flow, is associated with significant pain relief, and could be proven an excellent alternative therapy, improving the life quality. Significant TcPO(2) increase within the 2-week test period, is a predictive index of therapy success and should be considered before the final decision in terms of cost effectiveness, before the permanent implantation.