Pelvic floor maximal strength using vaginal digital assessment compared to dynamometric measurements

To compare vaginal digital assessment with dynamometric measurements for determining the maximal strength of the pelvic floor muscles (PFM).

Eighty-nine women aged between 21 and 44 participated in the study. An experienced physiotherapist evaluated the maximal strength of the PFM of these women using the modified Oxford grading system (six categories, range 0-5) and dynamometric measurements. The mean maximal forces obtained for all women with the instrumented speculum for each category of digital assessment were compared using ANOVAs. Spearman's rho coefficients were calculated to assess the correlation between the dynamometric and the digital assessments.

According to their symptoms and pad test results, 30 women were continent and 59 had stress urinary incontinence (SUI). Based on dynamometric measurements, important overlaps were observed between each category of digital assessment. The ANOVAs indicated that force values differ across categories (F = 10.08; P < 0.001), although contrast analyses revealed no differences in the mean maximal forces between adjacent digital-assessment categories (1-2, 2-3, 3-4, 4-5). Mean force values differed significantly only between non-adjacent levels in digital assessment, for example, between 1 and 3; 1 and 4; 1 and 5; 2 and 4; 2 and 5 (P < 0.05). Significant correlations were found between the two measurements with coefficients of r = 0.727, r = 0.450, and r = 0.564 for continent, incontinent, and all women, respectively (P < 0.01).

Even if the dynamometric mean forces of the PFM increased across subsequent categories of digital assessment, the force values between two adjacent categories do not differ. This limitation of digital assessment should be considered by clinicians and researchers when choosing treatment orientation and evaluating treatment outcomes.