Figure 1 How the hemostat test mimics normal control of SUI.
Upper figure A firm pubourethral (PUL) attaches to the lateral
part of urethra, pubococcygeus muscle (PCM) and vagina [6]. It
prevents the posterior reflex closure forces LP (levator plate) and
conjoint longitudinal muscle of the anus (LMA) acting on the trigone to
pull open the posterior urethra during effort [5]. Likewise, in SUI
women, transverse and retropubic tapes create new collagen below the
midurethra to prevent elongation of a loose or weakened PUL during
effort.
Normal urethral closure Three reflex directional muscles forces
close urethra: pubococcygeus (PCM) contracts forwards against PUL to
close distal urethra; levator plate (LP), contracts backwards to tension
PUL, and to stretch bladder base and trigone backwards for LMA (conjoint
longitudinal muscle of the anus), to pull the anterior tip of LP
downwards https://www.youtube.com/watch?v=3vJx2OvUYe0
This downward action rotates bladder base around PUL and pubovesical
insertion into the arc of Gilvernet (not shown) to close urethra at
bladder neck [5].
Stress urinary incontinence If PUL is weak or loose, it cannot
sustain the powerful posterior forces LP/LMA on effort; it lengthens,
the anterior vaginal and trigone are pulled downwards; urethra is opened
from “C” closed to “O” open; urine is lost on effort [5]. The
hemostat mechanically supports PUL, prevents lengthening and controls
SUI, as in the VIDEO and right ultrasound frame.
Lower figure The ultrasound figures show typical geometry of
SUI caused by loose PUL [9]. Left frame : REST. Urethra
closed. Structures in normal anatomical position, S=symphysis;U=urethra;
B=bladder; “a”& “p” = anterior and posterior walls of vagina; red
broken lines mark a whitish continuum which represents distal
ligamentous support of the urethra from EUL=external urethral ligament
to the yellow dots which mark another thickening, the pubourethral
ligament . Middle frame : STRAINING. Pubourethral ligament (yellow
dots) lengthens and cannot sustain the posterior forces acting on the
anterior (“a’) and posterior (“p”) walls of the vagina are tensioned
and pulled backwards/downwards. The urethra is opened along its length;
urine is lost on effort. Right frame ; MID/UR ANCHOR A hemostat
placed at midurethra as in the video mechanically supports PUL (yellow
dots), prevents lengthening and restores continence, as in VIDEO1.