Modification of blood flow to the extremities by electrical stimulation of the nervous system

Sixteen patients who had electrical stimulation applied to various portions of the nervous system were examined for increase in blood flow to the extremities. Clinical observations and a one-channel plethysmograph were used to measure arterial dilatation. Seven patients had transcutaneous stimulation applied over the cervical or thoracic spinal cord, peripheral nerves, or low lumbar region; eight had electrical stimulators implanted over the spinal cord in attempts to relieve intractable pain or some of the symptoms of multiple sclerosis; and one patient had electrical stimulators implanted over the C-6 dorsal roots for small artery disease of the upper extremities. Twelve of 13 patients who had electrical stimulation applied to the spinal cord or dorsal roots had significant arterial dilatation in one or more extremities. Electrical stimulation applied to the ulnar nerves did cause arterial dilatation. One patient did not show any change in the central arterial pressure curve during transcutaneous stimulation of the cervical spinal cord.