Stress urinary incontinence is caused predominantly by urethral support failure

Abstract

Whales are mammals that can dive to depths of > 1000 m without the high water pressure pushing open their mouth or anus. The same is true for the female urethra. The meatus externus and internus are seals that cannot be pushed open by high water pressures. Recent evidence suggests that the female meatus internus is pushed open when the bladder pressure exceeds the urethral pressure. For a relaxed detrusor, this opening is not possible for at least three reasons: the law of elastic collision, Pascal’s law of hydrostatics and the Hagen-Poiseuille law. The three laws do not support that urethral function failure is the predominant cause of stress urinary incontinence (SUI); however, they do support that urethral support failure is. Influential urogynecologists claim the opposite. TVT surgery, according to the integral theory of SUI (IT), has high failure rates because it does not principally prevent the urethra from hanging on a less mobile bladder neck. In the case of a long urethra, the tape is set too distally, and in hypomobile SUI, the use of a tension-free suburethral tape is unwarranted/ineffective, because the proximal urethra is not elevated above its resting position. A successful operation corrects urethral support failure and not urethral function failure.

Stress urinary incontinence: Bladder neck closure (BNC)—The real bottom line rather than urethral support or function failure

“…To the Editor, A recent article 1 proposes urethral support failure rather than urethral function failure as the principal cause of urodynamically proven stress urinary incontinence (SUI). 2 The article's author cites many earlier papers on a "Urethral Hanging Theory (UHT)."…”

“…We suggest that there might be relatively simple (i) clinical "bottom line" (i.e., degree of BNC) and (ii) mechanical (i.e., "cantilever effect") explanations for how SUI occurs and how it can be cured by a MUS. Urethral support or function failure are clearly relevant factors for SUI, though they have yet to show any consistency in the literature 1,[4][5][6]10 in predicting the diagnosis of SUI.…”

Comparing urethral closure mechanisms

“…The recent debate about closure mechanisms for the urethra [ 1 , 2 , 3 ] is important, because without a clear understanding of the anatomy of closure and non-closure (SUI – stress urinary incontinence), the surgeon can never understand how corrective surgery works, or how to systematically address complications of such operations.…”

“…Drs Delancey and Ashton-Miller present pressure data to support their view that a closed urethra is an important part of the continence mechanism [ 1 ]. No mechanism is given, other than a reference to Dr De Lancey’s ‘hammock hypothesis’, which relies on pressure transmission theory for urethral closure, as does Dr Bergstrom’s ‘Urethral hanging’ hypothesis [ 2 ]. The urethra is an emptying tube connecting the urine reservoir to the outside.…”

“…It is not sufficient for hypotheses [ 1 , 2 ] to explain continence by raised intrabdominal pressure closing the urethra. They need to explain Dr Gold’s clarifying test for pressure transmission hypotheses [ 3 ], “Why does straining during micturition not close the urethra , but rather, straining increases urine flow?” This test is anatomically explained in Figure 1 and VIDEO2: https://www.youtube.com/watch?v=eiF4G1mk6EA&feature=youtu.be During micturition, the forward vector pubococcygeus (PCM) relaxes; this allows the two posterior vectors LP/LMA (LP – levator plate; LMA – longitudinal muscle of the anus), to open out the urethra prior to micturition [ 4 ]; straining presses on the bladder to increase urine flow.…”