Late outcome of spinal cord stimulation for unreconstructable and limb-threatening lower limb ischemia.

Abstract

To determine whether the initial benefits of spinal cord stimulation (SCS) treatment for critical limb ischemia (CLI) persist over years. Analysis of data prospectively collected for every CLI patient receiving permanent SCS. Follow-up range 12 to 98 months (mean 46+/-23, median 50 months). 87 patients (28% stage III, 72%stage IV) with unreconstructable CLI due (83%) or not (17%) to atherosclerosis and with an initial sitting/supine transcutaneous pO2 gradient >15 mmHg. Assessment of actuarial patient survival (PS), limb salvage (LS) and amputation-free patient survival (AFPS). Analysis of the impact of 15 risk factors on long-term outcomes using the Fischer's exact test for categorical variables and the t test for continuous variables. Follow-up was complete for patient and limb survival. A single non-atherosclerotic patient died during follow-up. Among atherosclerotic patients PS decreased from 88% at 1y, to 76% at 3y, 64% at 5y and 57% at 7y. LS reached 84% at 1y, 78% at 2y, 75% at 3y and remained stable thereafter. Diabetes was found to affect LS (p<0.05) and heart disease to reduce PS (p<0.01). AFPS was reduced in heart patients (p<0.01), diabetics (p<0.05) and in patients with previous stroke (p<0.05). In CLI patients the beneficial effects of SCS persist far beyond the first year of treatment and major amputation becomes infrequent after the second year.