Observations on the function of the female urethra: III: An overview with special reference to the relation between urethral hypermobility and urethral incompetence.

Aims: To analyze the relation between urethral hypermobility and urethral incompetence, and to summarize the interdependence between maximum urethral closure pressure (MUCP), urethral hypermobility, and urethral incompetence. Patients and Methods: A group of 255 patients was selected from a large bank of cases. Inclusion criteria were age 20 years or above, no neurological disease, stable bladder, and no previous incontinence surgery or hysterectomy. The degree of hypermobility (cysto-urethrocele) and the degree of urethral incompetence (abdominal leak point pressure (ALPP)) were determined. Statistical analyses between urethral hypermobility and incompetence were performed with Spearman's correlation and the Jonckherre-Terpstra test. Results: The Spearman's rank correlation test showed a statistically significant relation between urethral hypermobility and the degree of urethral incompetence (P = 0.0049). Conclusions: The statistically significant relation between urethral incompetence and hypermobility suggests that urethral incompetence will increase as the degree of urethral hypermobility does. Optimal conditions for urinary continence include a high maximum urethral closure pressure, absence of hypermobility, and a low degree of urethral incompetence. This last factor is assured by a strong support underneath the urethra permitting compression of the latter during straining. Failure of the urethral closure mechanism is highly probable with a diminished maximum closure pressure accompanied by urethral hypermobility often associated with a high degree of urethral incompetence. Clinically significant urinary incontinence may appear in many intermediate circumstances between these two extreme states, but stress urinary incontinence is essentially an activity-related phenomenon. (C) 2003 Wiley-Liss, Inc.