Transperineal ultrasound measurement of the levator plate angle and anorectal angle is a useful method for evaluating uterine prolapse : a prospective cohort study

Abstract

Background Confirming the patient's cervical position using transperineal ultrasound is not an easy task. This study aimed to employ transperineal ultrasound to measure the levator plate angle (LPA) and anorectal angle (ARA) in patients with varying degrees of uterine prolapse and to explore their efficacy in assessing uterine prolapse. Methods This prospective study consecutively enrolled 130 female patients who underwent examinations for lower urinary tract or pelvic floor dysfunction symptoms at the Second Affiliated Hospital of Fujian Medical University from August 2022 to December 2023. Participants were divided into three groups based on the Pelvic Organ Prolapse Quantification (POP-Q) system: POP-Q = 0 (n = 45), POP-Q = 1 (n = 45), and POP-Q ≥ 2 (n = 40). Transperineal ultrasound was used to measure the LPA and ARA at rest (rLPA and rARA) and during maximum Valsalva maneuver (vLPA and vARA). Changes in LPA and ARA from rest to maximal Valsalva (ΔLPA and ΔARA) were calculated. The differences in these ultrasound parameters among the three groups were compared. The area under the curve (AUC) was calculated to assess the diagnostic performance. Results With increasing severity of uterine prolapse, vLPA decreased progressively, while vARA and ΔARA initially decreased and then increased (P < 0.05). Compared with the POP-Q stage = 0 group, rLPA was reduced in the POP-Q stage ≥ 2 group, and ΔLPA was reduced in the POP-Q stage = 1 and POP-Q stage ≥ 2 groups (P < 0.05). The optimal cutoff values for diagnosing POP-Q stage ≥ 1 were 27.01° for rLPA, -2.29° for vLPA, and − 26.11° for ΔLPA, with corresponding AUCs of 0.65, 0.86, and 0.75. For diagnosing POP-Q stage ≥ 2, the optimal cutoff values were 24.11° for rLPA, -6.97° for vLPA, and − 34.57° for ΔLPA, with corresponding AUCs of 0.67, 0.80, and 0.69. DeLong's test indicated that vLPA had the highest efficacy in diagnosing both POP-Q stage ≥ 1 and POP-Q stage ≥ 2 (P < 0.05). Conclusion Transperineal ultrasound measurement of the LPA and ARA is a simple and effective method for assessing uterine prolapse.