One of the challenges in assessing pelvic muscle function in women who have pain is to avoid triggering pain with the assessment tool. This challenge was met by the use of external measuring of pelvic floor muscles using transperineal four-dimensional (4D) ultrasound in this study by Morin and colleagues. Women who were asymptomatic (n=51) and symptomatic (n=49) were assessed with 4D ultrasound in supine with pelvic floor muscles (PFM) at rest and at maximal contraction. The women who were symptomatic were diagnosed with provoked vestibulodynia (PVD) and all of the women in the study were nulliparous. The data collected using the 4D transperineal US included anorectal angle, levator plate angle, displacement of the bladder neck, and levator hiatus.
Results of the study indicated that women with provoked vestibulodynia had a significantly smaller hiatus, smaller anorectal angle, and at rest, a larger levator plate angle. These differences suggested an increase in pelvic floor muscle tone. Additionally, when the PFM were assessed at maximal contraction, subjects with PVD demonstrated smaller changes in levator hiatus narrowing were noted, with decreased displacement of the bladder neck and decreased changes in levator plate and anorectal angles. These changes are believed to demonstrate pelvic floor muscle weakness.
The authors describe the value of the assessment technique, 4D ultrasonography, as having terrific advantage over other research methods due to the lack of required insertion of the US. While pelvic rehabilitation providers may concur that increased pelvic floor muscle tone in association with pelvic muscle weakness is a common clinical finding, research that describes the phenomenon is needed and much appreciated. We continue to find answers in research such as this article that answers the fundamental question: do women who present with pelvic dysfunction demonstrate differences in pelvic muscle health than a pelvic-healthy population? If you would like to learn more about provoked vestibulodynia including evaluation and management, join faculty member Dee Hartmann at the Assessing and Treating Women with Vulvodynia continuing education course. We are currently confirming dates for this course, and if you would like to host the Vulvodynia course, contact us at the Institute!