Etiopathogenesis of "bladder outlet obstruction" in the female- inability of pelvic muscles to sufficiently open urethra.

Abstract

Etiopathogenesis of abnormal female voiding- posterior pelvic muscles cannot adequately open urethra ABSTRACT No of words 200. Background Historically, opening the bladder neck and urethra for evacuation has been solely by detrusor contraction with "urethral relaxation." Summary We present a change in thinking based on clinical and experimental research, human and animal: the urethra is opened externally immediately prior to detrusor contraction by posterior pelvic floor muscles contracting against competent USLs (uterosacral ligaments). A binary feedback control system (EITHER open OR closed) with neurological and peripheral musculo-ligamentous components is presented. Three oppositely-acting muscle vectors contract against suspensory ligaments to close urethra distally and at bladder neck; relaxation of the forward closure vector allows the two posterior muscles to contract against USLs to open the posterior urethral wall prior to voiding. In this context, bladder emptying difficulties, whether neurological, musculoligamentous damage, or obstructive, means that the detrusor must contract against an unopened urethra which presents a high resistance to flow, clincally perceived as "emptying difficulties". Key message A change in thinking: posterior pelvic muscles contract against a firm USL to open posterior urethral wall prior to voiding: VIDEO https://www.youtube.com/watch?v=nK0CQmaS-5E&t=7s Weak USLs from birthing or age weaken the opening muscles. Strengthening the USLs, surgically, or by pelvic exercises, or mechanical support by pessaries can be effective in selected patients.