Neurophysiologic testing in chronic pelvic pain syndrome: A pilot study

Objectives. Studies of male chronic pelvic pain syndrome (CPPS) have genera lly centered on the pathologic features of the prostate rather than on the neurology of pain. Electrodiagnostic studies examine the integrity of somat osensory nerve pathways consisting of large, group A fibers. Heat sensation and visceral (autonomic) pain is mediated through small, unmyelinated C fi bers, which can be tested cutaneously by thermal sensory analysis. We hypot hesized that CPPS pain is mediated by these small C fibers. Methods. All subjects and controls had no history of neurologic disease and had normal neurologic examinations. Phase I: 14 patients with CPPS underwe nt electrodiagnostic testing using pudendal somatosensory evoked potentials and bulbocavernosus reflex latency measurements. Phase II: 31 patients wit h CPPS and 14 controls underwent thermal sensory analysis testing on the pe rineum and anterior thigh using noxious heat stimuli. Subjects used a compu ter-generated visual analog scale to dynamically report their discomfort. T he peak and slope of the computer-generated visual analog scale were analyz ed. Results. Phase I: two patients had delayed latency of the somatosensory evo ked potentials, but additional evaluation with magnetic resonance imaging r evealed no definable lesion. Phase II: with thermal sensory analysis, men w ith CPPS reported higher intensity pain at lower temperatures [P = 0.03). M en with CPPS also had higher peak computer-generated visual analog scale sc ores on perineal testing. No difference in thermal testing on the anterior thigh was found between the two groups. Conclusions. Large, myelinated somatic fibers do not play a significant rol e in the pathophysiology of CPPS. Patients with CPPS have an altered sensat ion of perineal pain elicited by heat, which may represent a C-fiber-mediat ed effect. UROLOGY 58: 246-250, 2001. (C) 2001, Elsevier Science Inc.