The association between different measures of pelvic floor muscle function and female pelvic organ prolapse.

Introduction and Hypothesis: We aimed to compare palpatory and translabial ultrasound (TLUS) measurements of pelvic floor muscle (PFM) function with symptoms and signs of female pelvic organ prolapse (FPOP) to determine a possible association.
Methods: We analysed data from 726 women with a mean age of 56 (SD 13.7, range 18-88) years, seen for symptoms of pelvic floor dysfunction between August 2011 and April 2013. The examination included a standardised interview and clinical assessment of FPOP with Pelvic Organ Prolapse Quantification (POP-Q) measurements, Modified Oxford Scale (MOS) grading and 4D TLUS.
Results: Symptoms of prolapse were reported in 51.4% (373 out of 726) with a mean bother score of 5.8 (SD 2.91, range 0-10). A clinically significant POP (Incontinence Society [ICS]-POP-Q stage ≥ 2) in any compartment was diagnosed in 77.1%. Mean MOS was 2.4 (SD 1.1, range 0-5). Significant POP on TLUS was seen in 54.6% (389 out of 712). TLUS volumes at rest and on maximal PFM contraction were analysed on a desktop PC, to assess the degree of bladder neck (BN) cranioventral shift and levator antero-posterior (AP) diameter reduction, blinded against other data. Mean cranioventral BN shift was 7.11 (SD 4.36, range 0.32-25.32) mm and mean levator AP diameter reduction was 8.6 (SD 4.8, range 0.3-31.3) mm. MOS was strongly associated with subjective and objective POP (P ≤ 0.001), whereas this was not true for TLUS measurements of tissue displacement.
Conclusion: The MOS seems to be a more valid measure of PFM function than sonographically determined BN displacement or reduction of hiatal AP diameter observed on PFM contraction.