Vulvar vestibulitis severity--assessment by sensory and pain testing modalities

Vulvar vestibulitis syndrome (VVS) is a common cause of dyspareunia in pre-menopausal women. Previous quantitative sensory test (QST) studies have demonstrated reduced vestibular pain thresholds in these patients. Here we try to find whether QST findings correlate to disease severity. Thirty-five vestibulitis patients, 17 with moderate and 18 with severe disorder, were compared to 22 age matched control women. Tactile and pain thresholds for mechanical pressure and thermal pain were measured at the posterior fourcette. Magnitude estimation of supra-threshold painful stimuli were obtained for mechanical and thermal stimuli, the latter were of tonic and phasic types. Pain thresholds were lower and supra-threshold magnitude estimations were higher in VVS patients, in agreement with disease severity. Cut-off points were defined for results of each test, discriminating between moderate VVS, severe VVS and healthy controls, and allowing calculation of sensitivity and specificity of the various tests. Our findings show that the best discriminative test was mechanical pain threshold obtained by a simple custom made 'spring pressure device'. This test had the highest kappa value (0.82), predicting correctly 88% of all VVS cases and 100% of the severe VVS cases. Supra-threshold pain magnitude estimation for tonic heat stimulation also had a high kappa value (0.73) predicting correctly 82% overall with a 100% correct diagnosis of the control group. QST techniques, both threshold and supra-threshold measurements, seem to be capable of discriminating level of severity of this clinical pain syndrome.