DYSESTHETIC PAIN IN PATIENTS WITH SYRINGOMYELIA

DYSESTHETIC PAIN IS a common complaint of patients with syringomyelia, traumatic paraplegia, and various myelopathic conditions. Because cav itary lesions of the spinal cord can be defined with good resolution b y magnetic resonance imaging, syringomyelia provides a potential model for examining anatomic correlates of central pain. In this study, a s yndrome of segmental dysesthesias, characterized by burning pain, hype resthesia, and a variable incidence of trophic changes, was described by 51 of 137 patients (37%) with syringomyelia at the time of clinical presentation. Complete magnetic resonance scans, including axial imag es, demonstrated extension of the syrinx into the dorsolateral quadran t of the spinal cord on the same side and at the level of pain in 43 o f 51 patients (84%). Surgical treatment of syringomyelia resulted in t he relief or improvement of dysesthetic pain in 22 of 37 patients (59% ), but 15 patients (41%) reported no improvement or an intensification of pain despite collapse of the syrinx. Postoperative dysesthetic pai n was often a disabling complaint that responded poorly to medical the rapy, including analgesics, sedatives, antiepileptics, antispasmodics, and anti-inflammatory agents. In most cases, there was a gradual impr ovement of symptoms, although six patients continued to complain of pa in 24 to 74 months postoperatively. Prompt but transient relief was ac hieved in two of two patients with regional sympathetic blocks, and pr olonged relief was achieved in one patient by stellate ganglionectomy. We conclude that painful dysesthesias can be caused by a disturbance of pain-modulating centers in the dorsolateral quadrant of the spinal cord and have certain causalgia-like features that respond in an unpre dictable way to surgical collapse of the syrinx.