Does age affect visualization of the levator ani in nulliparous women?

Abstract

Our aim was to assess whether differences in the ages of nulliparous women affect: (1) interobserver reliability, and (2) visualization of the levator ani (LA) muscle subdivisions in nulliparous women using 3D endovaginal ultrasound (3D-EVUS). This was a cross-sectional study. Community-dwelling nulliparous women ages 21-70 years were recruited. Participants underwent a standard examination and a 3D-EVUS. LA subdivisions of interest included the puboperinealis, puboanalis, pubococcygeus, puborectalis, and ileococcygeus muscles. Each ultrasound (US) volume was scored using a validated scale and assessed by two observers. Defect severity was scored for each muscle from 0 (no defect) to 6 (complete muscle loss). A summed score of the two sides was grouped as normal (0), minor (1-3), or major (4-6). Bias was examined using Bland-Altman plots. Intraclass coefficients were calculated to report agreement of total scores. Spearman's rank correlation was used to evaluate the association between age and LA scores. Eighty nulliparous women were evaluated. Exact agreement for bilateral scoring of each LA subdivision ranged from 82 % to 84 %. Bilateral scoring of the puboperinealis, puborectalis, and ileococcygeus showed moderate to substantial agreement. Bilateral scores of the puboperinealis demonstrated substantial agreement between observers, with an ICC of 0.8 and a mean difference of -0.2 using the Bland-Altman analysis. When women were analyzed by age decade, reader agreement was overall good to excellent. There was no significant correlation between increasing age and total LA muscle scores (r = 0.179, p = 0.113). Interobserver reliability or visualization of the LA muscle in nulliparous women was not affected by a woman's age.