Spinal cord stimulation in critical limb ischemia of the lower extremities: our experience

Spinal cord stimulation (SCS) improves microcirculatory blood flow, relieves ischemic pain and reduces amputation rate in patients with severe peripheral arterial occlusive disease.

To evaluate the specific prognostic parameters in the prediction of successful SCS and to perform a retrospective data analysis obtained during our patient follow-up.

150 patients (97 men, 53 women; mean age: 68 years; range: 46-81) were submitted to implantation of a spinal cord electrical generator for rest pain, and trophic lesions with dry gangrene in severe lower limb ischemia, after failed conservative or surgical treatment. The clinical status was classified as Fontaine's stage III and IV and the main pathology was essentially due to atherosclerosis and diabetic vascular disease. In clinical controls, pedal transcutaneous oxygen tension (TcPO2), ankle and toe pressure Doppler measurements were utilised to select and follow-up the patients.

After a mean follow-up of 71 months (range 24-138), pain relief >75% and limb salvage was achieved in 85 patients. In 28 patients was obtained a partial success with pain relief >50% and limb salvage for at least 6 months, while in 37 patients the method failed or for technical problems the device was removed, and the patients were amputated. TcPO2 was assessed on the dorsum of the foot. Clinical improvement and SCS success was associated with the increasing of TcPO2, before and after implantation (temporary period). Limb salvage was achieved in the patients that presented significant TcPO2 changes within the first 2 weeks of the testing period, indifferent from the stage of the disease, and from the initial TcPO2 value. After long-term patient follow-up TcPO2 changes, from 22.6 to 43.1 mm Hg in these with rest pain (p<0.01), from 16.2 to 36.1 mmHg (p<0.02) in those with trophic lesions <3 cm2, and from 12.4 to 28.1 in the patients with trophic lesions >3 cm2. A TcPO2 increase of more than 50% in the first 2 months after implantation was predictive of success, and was related with the presence of adequate paresthesias in the painful area during the trial period. The systolic ankle/brachial blood pressure index did not change under stimulation.

In patients with failed conservative and surgical treatment for severe critical lower limb ischemia, the SCS increases the skin blood flow, is associated with a significant pain relief and could be proven an excellent alternative therapy that improves the quality of life. TcPO2 changes, within a test period of 2 weeks, is a predictive index of therapy success and should be considered before the final decision in terms of cost effect, for the permanent implantation.