Intrinsic urethral sphincteric deficiency: critical analysis of various diagnostic modalities

The proper diagnosis of intrinsic urethral sphincteric deficiency among women with urinary incontinence carries important implications for determining the most effective medical or surgical therapy. Numerous diagnostic tests have been described attempting to make an accurate and comprehensive assessment of urethral function, but all suffer from a lack of standardization or inconsistently quoted reference values. This paper will review the literature on the positive aspects and limitations of commonly employed procedures to diagnose intrinsic urethral sphincteric deficiency.

Specific urodynamic studies, including the 'active' valsalva leak-point pressure and the 'static' urethral pressure profile are commonly used to determine urethral competence. However, these tests measure specific aspects of the continence mechanism under different clinical conditions, which limits the direct comparison between them. More complex techniques such as Doppler ultrasound, video-urodynamics and both static and dynamic magnetic resonance imaging are attempting to validate the urodynamic findings for urethral function. This approach may encourage the standardization of these procedures and parameters for diagnosing intrinsic urethral sphincteric deficiency.

A single definitive test for the diagnosis of intrinsic urethral sphincteric deficiency does not exist. Instead, multiple tests should be employed to reach a consensus for the diagnosis. This should include a complete voiding history, simple office examinations, and advanced studies such as urethrocystoscopy, urodynamics and possibly radiological evaluations. Understanding the limitations and variabilities of their equipment and the specific studies utilized should enable practitioners to standardize the approach for determining the extent of urethral dysfunction.