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

INTRODUCTION AND HYPOTHESIS: 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). METHODS: 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. RESULTS: 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). CONCLUSIONS: Interobserver reliability or visualization of the LA muscle in nulliparous women was not affected by a woman's age.