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| VULVODYNIA: ALTERED CENTRAL PROCESSING MAINTAINED BY PERIPHERAL INPUTS? Richard Gracely, Ph.D., Clinical Measurement and Mechanisms Unit, Pain and Neurosensory Mechanisms Branch, National Institute of Dental Research, National Institutes of Health; Bethesda, Maryland Vulvodynia is a syndrome characterized by nearly constant spontaneous burning and itching pain in the vulvar vestibule, accompanied by touch-evoked pain (allodynia) within the vestibule and in adjacent perineal structures. The mechanism(s) responsible for vulvodynia are not known. We tested the hypothesis that vulvodynia is due to altered central processing maintained by focal input from vestibular glands. Six women with chronic vulvodynia were screened for absence of local infection and abnormal MRI of the lumbrosacral spine. All patients used a 0-20 verbal-numerical category (VNC) scale to rate sensations evoked by a cotton applicator applied to 20 standard test sites within and adjacent to the vestibule. These sites were tested before and three times after infiltration of 0.1-0.2 ml 2% lidocaine without epinephrine into each of 4 sites (left and right Bartholin's and Skene's ducts) and, in 3 patients, in the minor vestibular glands in the infraclitoral area. VNC scores of pain evoked at the injection sites (mean 19.5) were reduced at 5 min (VNC=5.8, p<.0001) and 16 min (VNC=6.4, p<.001) after the injection, revealing local anesthesia, which had waned by 28 min (VNC=12.5, p=.084). VNC scores of pain evoked at other sites (mean 11.1) also were reduced significantly at 5 min (VNC=4.5, p<.00 1) and 16 min (VNC=4.0, p<.005) after the injection, but not at 28 min (VNC=7.3, p=.11) These results suggest that vulvodynia results from altered central processing dynamically maintained by nociceptive input from focal areas that surround the openings of the vestibular glands. This altered central processing results in widespread allodynia and other symptoms. Therapy directed towards these focal sites may provide successful treatment.
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