**5. Stress urinary continence and incontinence**

During stress (coughing or straining) the intraurethral pressure rises in normal patients. The rise in pressure within the urethra precedes the rise in pressure in the bladder by 160-240 milliseconds (Enhorning 1961, Constantinou and Govan 1982, van der Kooi et al. 1984, Pieber et al. 1998). This means, that the increased pressure within the urethra during stress must be due to an active muscle contraction and cannot be a passive transmission of the abdominal pressure.

In addition to the contraction of the rhabdosphincter at midurethra, the PCM pulls the distal vagina forward to close the distal urethra (figure 3). Furthermore, the bladder and posterior vaginal wall is pulled backwards (by levator plate) and downwards (by LMA). With intact pubourethral ligament the urethra is stretched and angulated to "kink" the proximal urethra (Petros and Ulmsten 1995). This action is an important closing mechanism, which, as known, helps many patients maintain continence after excision of the distal urethra.

The Integral Theory (1990, 1993) states that "stress urinary incontinence ... derives mainly from laxity in the vagina or its supporting ligaments, a result of altered collagen/elastin". A hypermobile urethra results from loose connective tissue. In stress situations,

washing lines (Nichols 1989). The cardinal ligaments are attached to the cervical ring and pubocervical fascia and extend laterally towards and above the ischial spine. The cervical ring surrounds the cervix and acts as an attachment point for the cardinal and uterosacral ligaments as well as the pubocervical and rectovaginal fascia. It consists mainly of collagen. The "pubocervical fascia" – a term still used by surgeons - stretches from the lateral sulci of the vagina to the anterior part of the cervical ring, it is a vaginal muscularis and

In the **posterior zone**, which reaches from the cervix to the anal canal, the following 3

The uterosacral ligaments arise from the sacral vertebrate S2,3,4 and attach to the cervical ring posteriorly. It is an effective insertion point of the downward muscle force, the longitudinal muscle of the anus (LMA). The rectovaginal fascia extends as a sheet between the lateral rectal pillars, from the perineal body below to the levator plate above. It is attached to the uterosacral ligaments (USL) and the fascia surrounding the cervix. The perineal body lies between the distal third of the posterior vaginal wall and the anus below the pelvic floor. It is 3-4 cm long. According to DeLancey (1999), it is formed primarily by the midline connection between the halves of the perineal membrane. It is the insertion point of bulbocavernosus muscle and deep and superficial transverse perinei

**Micturition** Broken line below bladder signifies relaxation of PCM; LP/LMA vectors actively open out the urethra exponentially decreasing frictional resistance to micturition

**Defecation** Broken line behind rectum signifies relaxation of PRM; LP/LMA vectors actively open out the anorectum, exponentially decreasing frictional resistance to

During stress (coughing or straining) the intraurethral pressure rises in normal patients. The rise in pressure within the urethra precedes the rise in pressure in the bladder by 160-240 milliseconds (Enhorning 1961, Constantinou and Govan 1982, van der Kooi et al. 1984, Pieber et al. 1998). This means, that the increased pressure within the urethra during stress must be due to an active muscle contraction and cannot be a passive transmission of the

In addition to the contraction of the rhabdosphincter at midurethra, the PCM pulls the distal vagina forward to close the distal urethra (figure 3). Furthermore, the bladder and posterior vaginal wall is pulled backwards (by levator plate) and downwards (by LMA). With intact pubourethral ligament the urethra is stretched and angulated to "kink" the proximal urethra (Petros and Ulmsten 1995). This action is an important closing mechanism, which, as known, helps many patients maintain continence after excision of

The Integral Theory (1990, 1993) states that "stress urinary incontinence ... derives mainly from laxity in the vagina or its supporting ligaments, a result of altered collagen/elastin". A hypermobile urethra results from loose connective tissue. In stress situations,

**5. Stress urinary continence and incontinence** 

fibromuscular wall (Corton 2009).

structures can be loose.

muscles.

defecation

abdominal pressure.

the distal urethra.

abdominal forces stretch loose tissues in the anterior zone (pubourethral ligament, extraurethral ligament, hammock), leading to overlengthening of the rhabdosphincter. According to Gordon`s relation between muscle length and muscle force, as soon as the muscle force diminishes … (by half/etc), the patient is stress incontinent. Overstretched connective tissue leads also to an increased radius within the rhabdosphincter and the urethra. According to Laplace's law, the pressure within the urethra correlates inversely to the radius within the rhabdosphincter. In loose connective tissue, the pressure within the urethra thus diminishes in line with the increasing radius. The Hagen-Poiseuille`s law is also helpful in describing continence. The resistance to flow within the urethra in stress situations correlates directly to the length of the urethra and indirectly to the radius within the urethra in the 4th power (Bush et al. 1997). Stress in patients with loose connective tissue will open the urethra. The stress flow then correlates to the radius of the urethra in 4th power.

In other words, loose connective tissue can lead to reduced muscle force by overstretching the muscle, reduced urethral pressure by increasing the radius within the rhabdosphincter, and reduced resistance to flow by widening the urethral radius.

These correlations have a major impact on interpretation of urodynamic results and should be considered in the future.

Petros has been developing the midurethral sling since 1986 based on research on the laxities of the vagina and supporting ligaments and loose connective tissue. (Petros and Ulmsten 1990, 1993)

B=bladder; U=urethra; V=vagina; CX=cervix; R=rectum; PUL=pubourethral ligament; Bv=attachment of bladder base to vagina; LMA= conjoint longitudinal muscle of the anus; LP=levator plate; USL=uterosacral ligament.

Fig. 3. Directional movements of bladder and urethra during effort. a) Lateral xray in resting position, sitting. b) Lateral xray during straining, same patient, shows forward movement of distal vagina and urethra and backward/downward rotation of proximal vagina and urethra ,around the pubourethral ligament (PUL) at the midurethral point. c) Muscle actions during effort- schematic view. PCM pulls the distal vagina forwards to close the distal urethra; LP/LMA stretch the proximal vagina and urethra backwards/downwards to close off the proximal urethra. (From PPetros 2010, by permission).

The Role of Altered Connective Tissue in the Causation of Pelvic Floor Symptoms 11

increasingly found that supported their claim that a correlation between the prolapse and an

Figures 2, 3b and 5 show that the bladder lies on the vaginal wall. With effort the posterior vaginal wall is orientated horizontally and the bladder lies on this part of tensioned vaginal wall (figure 3b), which acts as a "trampoline". The vagina is attached to the pelvic rim by the uterosacral ligaments posteriorly, the arcus tendineus and the cardinal ligaments laterally as well as the pubourethral ligament anteriorly. Anterior and posterior muscle forces (red arrows in figure 5) add to tension the vaginal wall. While the slow twitch fibres are active when at rest, the fast twitch fibres are active during effort. At the bladder base stretch receptors are present which are connected by afferent nerves to the cortex (Wyndaele et al. 2008, Everaerts et al. 2008, Petros & Ulmsten 1990). Efferent nerves can activate the pelvic

Fig. 5. Stability at the bladder base by a tensioned vaginal wall "Trampoline Analogy".

Petros and Ulmsten (1993) postulated that urgency could lead to a premature activation of the micturition reflex. A lax vagina at the anterior, middle or posterior zone reduces the

overactive bladder exists (de Boer et al. 2010).

floor musculature (figure 5).

(From P Petros 2010, by permission).
