[Vascular effects of spinal cord electrostimulation. Possible mechanisms of action].

Spinal cord stimulation has been demonstrated to be effective in the treatment of peripheral arteriopathies where neither medical nor surgical treatment is possible. Although there are various theories proposed, the mechanism of action is not yet clear. We studied the changes in transcutaneous PO2 as well as the sympathetic and parasympathetic cardiac activity in 42 patients with peripheral arteriopathies treated with spinal cord stimulation. Transcutaneous PO2 measured in percentage values showed a statistically significant increase 15 minutes (p less than 0.05) and 60 minutes (p less than 0.01) after generator connection. Disconnection produced a gradual decrease of transcutaneous pO2 with a minimal value at 70-180 minutes, maintained for various hours above basal values. The study of the changes in the expiratory/inspiratory quotient of the heart rate during spinal cord stimulation did not show any statistically significant differences with respect to a control group of healthy subjects. This demonstrates a preservation of parasympathetic activity. While studying the changes in heart rate from the decubitus to orthostatic position, the spinal cord stimulation group behaved similar to the group of patients who, for having undergone heart transplantation, had complete cardiac denervation the difference being statistically significant. The results obtained can clear up some questions as to the mechanisms of action of spinal cord stimulation and explain the clinical improvement obtained in this type of treatment for peripheral arteriopathies.