The role of invasive and non-invasive urodynamics in male voiding lower urinary tract symptoms.

Introduction: Troublesome voiding lower urinary tract symptoms (LUTS) are a common problem in men, particularly with ageing. Implicitly, management of voiding LUTS can be guided by accurate determination of underlying mechanisms, distinguishing men with voiding symptoms caused by outlet obstruction from those with reduced bladder contractility.

Methods: A PubMed search of the published literature on invasive and non-invasive methods used to assess lower urinary tract function was carried out.

Results: A multitude of methods have been applied to assess LUTS. Multichannel pressure flow studies (PFS) are the standard for diagnosing bladder outlet obstruction and underlying mechanisms of LUTS, though their invasive nature can be difficult to tolerate, and improved prediction of treatment outcome is disputed. Uroflowmetry and post void residual measurement are insufficient to make a definitive diagnosis. Ultrasound-derived measurements of bladder wall thickness and estimated bladder weight offer a potential non-invasive alternative to PFS, but their diagnostic parameters are still under evaluation. Non-invasive methods that measure isovolumetric bladder pressure by interrupting the urinary stream can reproducibly measure pressure and urinary flow, but are unable to determine the effects of abdominal straining during voiding and give no insight into urine storage symptoms. Doppler ultrasound during urethral flow is informative, but it is an expensive approach whose clinical utility has yet to be established.

Conclusion: A variety of non-invasive urodynamic and non-urodynamic techniques have been used to evaluate LUTS and some show great promise. However, there is as yet, insufficient evidence to justify replacement of invasive voiding cystometry by these investigational approaches.