The assessment of levator trauma: a comparison between palpation and 4D pelvic floor ultrasound

Major morphological abnormalities of the pubovisceral muscle are observed in 10-20% of women symptomatic of pelvic floor disorders. Such defects arise in childbirth and are associated with prolapse. While they are clearly evident on 3D ultrasound and MR imaging, such defects can be difficult to detect clinically. We intended to compare findings on palpation with the results of ultrasound imaging.

Fifty-five women were recruited in a prospective observational study and assessed by interview, vaginal examination by a trained pelvic floor physiotherapist, and 3D/4D pelvic floor ultrasound. The vaginal examination involved digital assessment of muscle strength (modified Oxford grading) and morphological abnormalities. The ultrasound examination involved acquisition of volume datasets taken at rest, on Valsalva and pelvic floor muscle contraction. Assessments were undertaken supine and after voiding. Ultrasound operator and physiotherapist were blind to each other's findings.

A comparison of 3D ultrasound and palpation was possible in 54 cases. Average Oxford grading was weakly associated with reduction in hiatal dimensions on contraction (r = -0.32, P = 0.024). A marked increase in hiatal dimensions detected on palpation was associated with increased hiatal area on Valsalva (P = 0.027). Defects were observed in 7/54 (13%) on ultrasound and in 10/55 (18%) on palpation. There was poor agreement between the methods, with only two defects picked up equally by both methods.

Palpation of the pubovisceral muscle correlates poorly with 3D/4D pelvic floor ultrasound imaging for the assessment of muscular defects.