VAGINAL ULTRASOUND STUDIES OF BLADDER NECK MOBILITY

Objective To introduce a simple, well-standardised vaginal ultrasound technique and to compare the position and mobility of the bladder neck in continent and stress incontinent women using this technique. Design A single-centre prospective case-control study. Setting Ikazia Hospital, Rotterdam, The Netherlands. Subjects One hundred and sixty women; sixty randomly chosen women referred to our outpatient department who volunteered for the study to develop a standardised technique, fifty stress-incontinent women and fifty controls who volunteered for the study for comparison using the standardised technique. Main outcome measures Standardisation with regard to bladder volume, horizontal axis and Valsalva force. The position of the bladder neck at rest, during straining and during squeezing. Results The probe we use does not alter bladder neck mobility. A standardised bladder volume of 250 ml was used rather than maximum bladder capacity. A Foley catheter introduced into the bladder, with the balloon half-filled with soapy water and half with air gives an easily recognisable fluid level, which is parallel to the horizontal axis of the patient. A standardised Valsalva force of 30 cm H2O can exclude differences in bladder neck mobility due to spontaneous and uncontrolled abdominal force. Measurements by two independently working investigators showed good conformity. The position of the bladder neck in the stress incontinent women was significantly lower and significantly more posterior at rest, during straining and during squeezing. At the same time in stress incontinent women there was significantly more descent during straining and less elevation during squeezing. However, there was a considerable overlap between the two groups for all parameters. Conclusions This standardised vaginal ultrasound technique is a feasible, acceptable and reproducible technique for the study of female bladder neck mobility. The position and mobility of the bladder neck is significantly different in stress incontinent women as compared to continent controls. The great overlap between the two groups still limits the clinical relevance.