Effects of peripheral nerve stimulation on the blood flow of the spinal cord and the nerve root.

Hemodynamic changes in the spinal cord and the nerve root caused by electrical sciatic nerve stimulation in anesthetized dogs were measured with a thermal diffusion method. The electrical stimulation increased the blood flow of the stimulated spinal cord and the nerve root. The conditions of stimulation giving the maximum increase of blood flow were different for the spinal cord and the nerve root. Strong stimulation at a high frequency of 50 to 100 Hz was effective for increasing the blood flow. In the spinal cord, an increase of the local metabolic rate appeared to be important for the blood flow increase. In the nerve root, the sympathetic nerves may have an important effect in the blood flow increase.