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

An anatomical pathway for restoration of bladder neck closure by a midurethral sling, according to the integral theory

“…The step-by-step cystoscopic technique during midurethral sling (MUS) insertion by Haylen et al 1 demonstrated that a sling placed at midurethra closed the urethra at the bladder neck, 1 an observation first demonstrated in 1990. 2 Another important validation was the local anesthetic "coughing" technique used in the prototype MUS operations 2 https://obgyn.onlinelibrary.wiley.com/toc/16000412/ 1990/69/S153 [3][4][5][6][7] to minimize postoperative urinary retention.…”

“…Though the statement that there is no leak with a closed urethra 1 is an obvious tautology, it is quite correct if "a closed urethra" is interpreted to mean "urethral resistance." Urethral resistance to flow, "Poiseuille's law," [8][9][10] is the ultimate mechanism for closure as described in the prototype MUS operations [2][3][4][5][6][7] and subsequently.…”

“…A “cantilever effect” hypothesis is proposed 1 to explain a frequent counterintuitive question most MUS experts encounter, “How can a sling placed at midurethra restore closure at bladder neck, a point 2 cm cephalad?” This question was anatomically explained by the 1990 integral Theory, 2 Figure 1; specifically, the pubovesical ligament (PVL) insertion into the Arc of Gil Vernet (a thickening in the anterior bladder wall at bladder neck), is stiffened by the posterior muscle vectors, to provide a firm rotation point by the downward vector (arrows), Figure 1.…”

“…The “cantilever” and “shear mechanism” hypotheses proposed for bladder neck closure 1 raise important questions. How can a urethra with no inherent stiffness allow a “shearing effect” 2 cm cephalad?…”

“…How can a urethra with no inherent stiffness allow a “shearing effect” 2 cm cephalad? As will be seen later in VIDEOs 1 and 2, the continence anatomy is not the solid wood or metal engineering of the hypothesis 1 whereby the whole urethra remains sufficiently rigid to be “sheared” at its urethral end to close the urethra at the bladder neck. This analogy does not hold for a soft tissue urethra.…”