To the Editor.
—In the Feb 19, 1988, issue of The Journal there was a question regarding persistent postoperative incisional pain following cholecystectomy. The answer by Dr Hermann1 suggested nonspecific measures for treatment of this kind of problem, but failed to mention the most common reason for undiagnosed persistent postoperative pain: development of a deafferentation-type pain, most commonly called reflex sympathetic dystrophy. While classically described as occurring in extremities, this type of pain can occur in any area of the body. Deafferentation-type pain occurs about 2% to 5% of the time after injury to afferent nerves and frequently is resistant to all forms of conventional therapy. Its etiology is not known. The pain can last months or years, and while many "conservative" therapies have been proposed to treat this disorder, the only reliably effective treatment is interruption of the sympathetic nerves to the area concerned. While injection of the