Objectives: To elucidate the implications of bladder neck funneling during straining in primary stress urinary incontinence.
Methods: Ultrasonography was performed in 320 consecutive patients who underwent a full urodynamic study and whose only diagnosis was primary genuine stress incontinence. The ultrasound assessment included measurement of the bladder neck angle at rest and during stress, as well as observation of the development of bladder neck funneling during the Valsalva maneuver.
Results: Of 320 study subjects, 111 had funneling of the bladder neck and 209 did not. Subjects with bladder neck funneling during stress had a significantly greater bladder neck angle at rest (P = 0.015) and during stress (P <0.001), greater rotation angle (P <0.001), lower maximal urethral closure pressure (P = 0.002), smaller proximal area under the urethral pressure profile curve (P = 0.002), higher incidence of low Valsalva leak point pressure (<60 cm H(2)O; P = 0.003), larger volume of urine leakage on a pad test (P = 0.006), and higher peak flow on a pressure-flow study (P = 0.028) than did those without. Bladder neck funneling on ultrasonography had a sensitivity of 59.5% and a specificity of 68.6% for the detection of low leak point pressure. The negative predictive value was 92.8%.
Conclusions: In primary genuine stress incontinence, bladder neck funneling on ultrasound cystourethrography implies the potential coexistence of poor anatomic support and an intrinsic sphincter defect, which require urodynamic investigation to verify. The high negative predictive value is useful in excluding the presence of low leak point pressure.