Comparing Vestibule Examination Techniques: Light Touch, Serial Forces, and the Lidocaine Test

The purpose of this study was to compare techniques and pain scales that assess tenderness in the vulvar vestibule in provoked vestibulodynia, using the cotton swab test and a vulvalgesiometer, and assess topical lidocaine solution with each.

This randomized study at a specialty vulvar clinic evaluated tender vestibules of reproductive-aged women with vestibulodynia using light rolling cotton swab touch at 6 sites and evaluated the vulvalgesiometer at 2 sites, randomizing the order of the initial tool. Participants reported pain using the Numerical Rating Scale 0-10 and the Verbal Pain Scale 0-3. With the vulvalgesiometer, the pain tolerance threshold was measured using forces of 10, 25, 50, 100, 200, and 300 g. After both initial tests, lidocaine 4% topical solution was applied for 3 minutes, and the swab test and vulvalgesiometer were repeated in the order initially performed, constituting the lidocaine test. Data analysis used t tests, Fisher exact tests, Wilcoxon signed rank tests, and Spearman rank correlation.

Sixteen patients completed the study, 8 starting with each instrument. Light swab touch evoked significant pain, and lidocaine reduced pain to zero or mild levels. The pain threshold was 25 g, and only 38% could tolerate testing past 100 g without lidocaine. The Verbal Pain Scale correlated well with the Numerical Rating Scale.

Light rolling cotton swab touch using the 4-item verbal scale can map vestibulodynia tenderness that can be extinguished by lidocaine, consistent with distinguishing a mucosal condition. Forces by vulvalgesiometer of greater than 100-200 g may evoke pain other than mucosal allodynia.