Validity of trans-perineum ultrasonic surveillance of percentage change in the levator ani hiatal antro posterior diameter for the diagnosis of pelvic floor muscle dysfunction

Objective To assess the validity of ultrasonic surveillance of percentage change in the levator ani hiatal antro posterior diameter (LHap) in the diagnosis of pelvic floor muscle dysfunction. Methods Two hundred and forty seven women suspected to have pelvic floor disorder related symptoms from January to December 2017 were enrolled. Digital palpation of the puborectalis muscle using modified Oxford score grading system (MOS) was performed.Women with MOS point of 0, 1, 2, or 3 were defined as having low pubic floor muscle contraction (LPFMC), and those with MOS point of 4 or 5 were defined as having normal pubic floor muscle contraction (NPFMC). Then ultrasound measurement of LHap diameter at rest, at maximum contraction, and at the maximum Valsalva were performed in all women to calculate the percentage decrease on contraction (PDC%) and percentage increase on Valsalva (PIV%). Statistical analysis was performed to test the significance of differences in PDC% and PIV% between the LPFMC group and NPFMC group, and the ROC curve analysis was performed to evaluate the validity of using PDC% and PIV% for predicting LPFMC. Results Compared with the NPFMC group, the PIV% of LPFMC group was significantly larger [(6.07±4.20)% vs (11.29±10.49)%, P 5.19% predicted LPFMC with sensitivity 71.43%, specificity 57.89%, and the area under the ROC curve was 0.69. A cut-off of PDC% 5.19% and PDC%<25.37%, the sensitivity was 84.55%, the specificity was 55.00%, and area under ROC was 0.70. Conclusions Ultrasonic measurement of percentage change in the LHap diameter is valuable for the diagnosis of pelvic floor muscle dysfunction. Key words: Ultrasonography; Pelvic floor muscle dysfunction; Levator ani hiatal antro posterior diameter