Accuracy of assessing Pelvic Organ Prolapse Quantification points using dynamic 2D transperineal ultrasound in women with pelvic organ prolapse.

INTRODUCTION AND HYPOTHESIS: We determined the relationship between clinical assessment of female pelvic organ prolapse (POP) using the validated Pelvic Organ Prolapse Quantification (POP-Q) and dynamic 2D transperineal ultrasound (TPUS).
METHODS: Women attending the urogynecology clinics between July and October 2009 were recruited. Prolapse was assessed using the POP-Q. Points Ba, Bp and C (anterior, posterior and middle compartments, respectively) were measured. TPUS was performed at maximum Valsalva by another clinician. As the TPUS probe compresses the prolapse that extends beyond the hymen, these women were excluded. A reference line was drawn parallel to the inferoposterior margin of the pubic symphysis, perpendicular to which the leading edge of descent was measured. The offset measured from the curved array of the probe to the reference line was added to the prolapse quantification on ultrasound (US) scan to make it objectively comparable with the POP-Q reference of the hymen. Points Ba, Bp and C on POP-Q were then compared with points of maximum descent achieved on TPUS.
RESULTS: One hundred and fifty-eight women had a POP-Q and TPUS; 20 scans (12.6 %) were not analysable, and 41 women had prolapse beyond the hymen. Ninety-seven women were thus analysed. The correlation between 2D TPUS (with/without the addition of the offset) and POP-Q was statistically significant (p value <0.0001) for all three compartments. The proportion of correct predictions was 59.6 %, 61.5 % and 32.6 % for bladder, bowel and middle-compartment prolapse, respectively.
CONCLUSION: These findings suggest that the accuracy of pelvic floor US staging is limited and that clinical assessment remains the gold standard.