Prolapse assessment supine and standing : do we need different cutoffs for "significant prolapse"?

Introduction and hypothesis Translabial ultrasound (TLUS) has shown good correlations between clinical examination and imaging findings in the supine position, and limits of normality have been described. This is not the case for imaging in the standing position. This study was designed to test the hypothesis that different cutoff values are required for imaging in the standing position. Methods This was a retrospective study carried out in a tertiary urogynecological unit in women presenting with symptoms of lower urinary tract and pelvic floor dysfunction between August 2013 and December 2015. All women underwent a standardized interview, 4D TLUS and a POP-Q assessment. Organ descent on ultrasound was measured relative to the postero-inferior margin of the symphysis pubis (SP) on maximal Valsalva in the supine and standing positions. Receiver operator characteristic (ROC) statistics were used to determine optimal cutoffs for "normal" pelvic organ support. Results We assessed 243 data sets. Mean patient age was 57 years. Prolapse symptoms were reported by 59.2%, and POP of stage ≥ 2 was found in 82.3%. On analysing imaging data sets obtained in the standing position, we obtained similar cutoff values to those established previously for supine imaging, using ROC statistics. The levator hiatus distended significantly more on Valsalva in the standing position compared with supine, and on ROC analysis we identified a new optimal cutoff of 29 cm2. Conclusions Established cutoffs for supine imaging of organ descent are suitable for imaging in the standing position. Hiatal distensibility may require a higher cutoff of 29 cm2.