Agreement between palpation and transperineal and endovaginal ultrasound in the diagnosis of levator ani avulsion

Our aim was to estimate agreement between transperineal and endovaginal ultrasound in assessing levator ani biometry and avulsion in nullipara and primipara women and determine agreement between levator avulsion palpation and ultrasound. This longitudinal cohort study assessed 269 nullipara women at 36 weeks gestation and 191 primipara women 13 weeks postpartum. Women underwent levator palpation, and avulsion was diagnosed if no attachment to the pubic bone was felt. Subsequently, 3/4D transperineal and 3D endovaginal ultrasound were performed. A standardized protocol was used to perform measurements at rest. Levator avulsion was diagnosed on endovaginal ultrasound at rest if > 50 % was avulsed and on transperineal tomographic ultrasound imaging at maximum contraction if the central three slices were avulsed. Levator avulsion was analyzed by two independent, blinded investigators. A third investigator resolved discrepancies. Intraclass correlation coefficient and limits of agreement were calculated for each time point. Intraclass correlation coefficient for levator urethra gap was 0.44-0.54, hiatus area 0.76-0.79, transverse diameter 0.51-0.59, anteroposterior diameter 0.70-0.72. Levator thickness correlated poorly. Endovaginal ultrasound measurements were generally smaller; however limits of agreement were acceptable for hiatus measurements. Overall agreement between both ultrasound techniques in diagnosing levator avulsion was 95 %; correlation 0.72 [95 % confidence interval (CI) 0.67-0.76]. Agreement between palpation and transperineal ultrasound was 92 % (kappa = 0.34), and between palpation and endovaginal ultrasound was 92 % (kappa = 0.37). Transperineal and endovaginal ultrasound can both be used to analyze hiatus area and anteroposterior diameter with the patient at rest and to diagnose levator avulsion. Palpation correlates only fairly with both methods.