The use of an occlusive penile clamp during filling cystometry in men with symptoms of stress urinary incontinence

Introduction: in severe post prostatectomy stress urinary incontinence (SUI), urodynamics may not identify crucial parameters because of inadequate bladder filling. This study describes evaluation of cystometry and pressure flow study (PFS) in men where severe SUI during attempted filling necessitated application of a penile clamp to allow filling to reach cystometric capacity. Methods: we identified all men who had undergone prior radical prostatectomy from a database of patients attending for videourodynamic testing between 2012-2017. Symptom scores, bladder diary and free flow rate tests were retrieved. We evaluated the measurements of the subgroup of men with severe SUI for whom a Thomson-Walker compression clamp was utilised to enable full urodynamic evaluation. Results: 166 radical prostatectomy patients were identified. In 30 (18%), severe SUI led to incomplete filling cystometry, i.e. failure to reach cystometric capacity. Following application of the penile compression clamp, it was possible to achieve further filling in each case. Applying the clamp did not alter vesical filling or impede pressure recording. These men had a lower maximum urethral closure pressure (31.6 vs 46.5cmH2O; p<0.001), volume at strong desire to void (132 vs 242mls; p=0.003) and cystometric capacity (226 with the clamp applied vs 310mls; P<0.001) when compared to the overall post prostatectomy incontinence population. Flow rates during PFS were comparable, but detrusor pressure at maximum flow was lower in the clamp group (11 vs 22cmH2O; p=0.009). Vesicoureteric reflux (VUR) was not seen in conjunction with the penile clamp use. Conclusions: this study shows that the use of a penile clamp during urodynamics for incontinent men who have had a radical prostatectomy can optimise the test by aiding additional bladder filling in selected patients. This allows for a clearer interpretation of cystometric capacity and ability to undertake PFS. The short-term use in this context is well tolerated and does not raise any safety concerns