An anatomical classification—a new paradigm for management of female lower urinary tract dysfunction

Abstract

A new anatomical classification specifies anatomical defects in the anterior, middle and posterior zones of the vagina as the cause of female lower urinary tract dysfunction. An external musculoelastic mechanism stretches the vagina to open and close the outflow tract. The same pelvic floor muscles provide a peripheral control mechanism for micturition. The stretched vagina prevents the filling bladder from activating the stretch receptors in the bladder neck. Vaginal laxity may weaken transmission of muscle forces, interfering with urethral opening and closure, a mechanical process. Laxity may also destabilize the peripheral control mechanism, a neurological process, causing bladder control to swing between the open and closed modes urodynamically interpreted as bladder instability. Specific symptoms, signs, and urodynamic tests can be arranged into a pictorial algorithm. This acts as a practical guide for locating the three zones of anatomical defects. It has been possible to reinterpret almost all the definitions and descriptions of the International Continence Society (ICS) in terms of this classification, and to explain how vaginal laxity may cause premature activation of the micturition reflex (detrusor instability), stress incontinence and abnormal emptying (dribble, overflow). This convergence in anatomical and urodynamic (ICS) concepts explains many previously unexplained phenomena, and potentially opens up a new approach to management, nonsurgical strengthening of specific ligaments, or surgical reinforcement thereof with ambulatory “microinvasive” methods which do not require catheterization.