Surgical therapy of chronic pain

Surgical therapy for chronic pain remains an important part of the management of the patient incapacitated by a wide variety of painful states. The surgical treatments can generally be grouped into those aimed at the peripheral nerve, the sympathetic nervous system, the spinal cord, and a variety of structures within the brain. Direct peripheral nerve surgery is valuable in a limited number of patients, with success rates of about 40%. Implanted peripheral nerve stimulators are highly effective, but are useful only in a small group of patients who respond to percutaneous nerve stimulation. Sympathectomy is curative in causalgia and has been reported to be effective for pain of biliary, pancreatic, and renal origin. It is not useful in the poorly defined reflex sympathetic dystrophy syndromes. Cordotomy remains the most important pain-relieving procedure, but is useful only in the treatment of pain of malignant disease. Late failure and the development of dysesthesias make it of little value in the management of chronic pain of a benign origin. Spinal cord stimulation has been used in a limited group of patients, and success rates of 50 to 70% have been achieved. Technical problems with the electronic devices limit the usefulness of the technique significantly. Midline myelotomy is a valuable procedure for pelvic pain. Destructive operations in the brain stem, thalamus, and cerebrum are of no value in the management of chronic pain. Stimulation in the upper brain stem and thalamus has been used in a small number of patients; success rates as high as 60 to 80% have been reported. The rationale of the technique is still not understood and it is used only by a few surgeons with a major dedication to the therapy of pain. Radiofrequency techniques have added a new dimension to pain therapy; trigeminal neuralgia is now effectively treated by radiofrequency neurotomy. Surgical procedures remain an effective part of pain therapy. They are most useful for specific problems, such as trigeminal neuralgia or causalgia, and for the pain of malignant disease. No good surgical therapies for pain of a benign origin that can be applied ubiquitously are available. The majority of surgical procedures for pain provide relief to a small percentage of the patients so treated and should be utilized only with careful patient selection. This patient selection should include a complete psychological characterization of the patient.