History of electrical neuromodulation for chronic pain

Electrical stimulation of the nervous system has a long history, starting in ancient Rome, progressing through the 19th century, and being applied with scientific intention since the beginning of the 20th century. In the middle of the last century, observations were made in the laboratory that stimulation of the septal area would result in profound analgesia, which led to similar stimulation being applied in patients with cancer pain. With the introduction of the Melzack-Wall gate theory, it became apparent that stimulation of the large somatosensory fibers in peripheral nerve and spinal cord might close the gate and inhibit chronic pain. In 1967, Wall and Sweet initiated therapeutic stimulation of peripheral nerve, and Shealy and Mortimer introduced spinal cord stimulation for chronic pain management. In 1973, Hosobuchi introduced somatosensory thalamus stimulation for treatment of denervation, and 4 years later, Richardson and Akil reported the use of periventricular stimulation for somatic pain. Along with advances in stimulation, improved patient selection has indicated both spinal and brain electrical neuromodulation for a variety of clinical types of chronic pain.