Assessment of pelvic floor muscle contractility: digital palpation versus 2D and 3D perineal ultrasound

The aim of our study was to investigate 2D and 3D ultrasound assessment of pelvic floor muscle contractility as an objective non-invasive diagnostic tool in urogynecologic patients. Patients from our urogynecological outpatient clinic were examined clinically by a single investigator including digital palpation as well as 2D and 3D perineal ultrasound. Muscle contractility was graded according to the modified Oxford Score and ultrasound images were saved for later analysis. Stored images were evaluated offline by another investigator blinded to all clinical data at a later stage. Bladder neck distance from pubic symphysis and symphysis-levator distance were measured in 2D at rest and during maximal pelvic floor muscle contraction. Hiatal area at the level of minimal hiatal dimensions as a 3D ultrasound parameter was measured at rest and during maximal pelvic floor muscle contraction, too. Spearman's rho was used to calculate statistical correlation between ultrasound parameters and digital assessment. A total of 114 patients were examined in our study. We found a significant correlation between modified Oxford Score and 2D ultrasound parameters of elongation of bladder neck length (Spearman's rho 0.292, p = 0.002) and reduction of symphysis-levator distance (Spearman's rho 0.0.301, p = 0.001), respectively. In addition, we detected a statistical significant correlation of modified Oxford Score and reduction of hiatal area in 3D ultrasound (Spearman's rho 0.458, p < 0.001), too. In this study, we found a significant correlation of subjective digital assessment of pelvic floor muscle strength with 2D and 3D ultrasound parameters as an objective diagnostic tool.