Foot salvage and improvement of microvascular blood flow as a result of epidural spinal cord electrical stimulation

Abstract

Epidural spinal cord electrical stimulation has been suggested as an alternative treatment in patients with limb-threatening ischemia in whom vascular reconstructive surgery is not possible anymore. We studied the effects of epidural spinal cord electrical stimulation on microcirculatory blood flow in 20 patients with ischemic rest pain and ulcers. Angiography showed occluded crural arteries technically unsuitable for reconstructive surgery. Intravital capillary microscopy was used to assess capillary density and diameter and red blood cell velocity before and after a 1-minute period of arterial occlusion. After epidural spinal cord electrical stimulation 18 patients claimed immediate pain relief, which was confirmed by intravital capillary microscopy. Capillary density increased from 10 to 19/mm2 (p < 0.001), red blood cell velocity increased from 0.088 to 0.496 mm/sec (p < 0.001), and peak red blood cell velocity after arterial occlusion increased from 0.092 to 0.548 mm/sec (p < 0.001). Two patients had no immediate pain relief; they did not show improvement of microcirculatory perfusion, and amputation was necessary. During the follow-up period (3 months to 3 years, mean 27 months), six other patients had recurrent ischemic pain, and amputation was necessary. In 12 patients pain relief continued, and ischemic ulcers healed; capillary microscopy confirmed improved microcirculatory blood flow. Microcirculatory parameters were significantly higher in respondents than in nonrespondents (p < 0.001). Life-table analysis revealed a cumulative foot salvage of 80% and 56% after 1 and 2 years, respectively. In conclusion, under special conditions in most of a short series of patients epidural spinal cord electrical stimulation relieved rest pain, improved skin nutritional flow leading to healing of ulcers of moderate size, and thus increased the salvage of feet with limb-threatening ischemia. Use of epidural spinal cord electrical stimulation can be considered when indicated by the results of capillary microscopy as an alternative treatment in patients with nonreconstructable occlusive arterial disease.