EPIDEMIOLOGY
Functional pathology of the pelvic floor,
causing different symptoms such as urinary incontinence,
uterine or vesical prolapse,
or fecal incontinency,
affects a high number of women,
ranging from 23.7 to 38% in the USA,
with a peak of more than 60% in elderly subjects.
Age
It has been reported (Goldstein) that urinary incontinence in patients from 61 to 65 years has a 22% higher prevalence compared to women aged 50 or less.
This difference increases up to 67% in women over 70 years.
In The USA,
a National Health and Nutrition Examination Survey (2006) found that approximately 24% of adult women have symptoms of at least one pelvic floor disorder.
This proportion increased with age: 39% of women aged 60-79 years and 50% of women aged 80 years or older suffered from at least one of those disorders.
Nygaard and colleagues found that in the United States in women over the age of 80 years the prevalence of urinary incontinence is 31.7%,
compared with women aged 40 to 59 with a prevalence of 17.2%.
As in the last 30 years population ageing is a matter of fact,
a 45% increase of pelvic floor–related disease is foreseen.
The importance of pelvic floor dysfunction is enforced to consider the changing demographics in Europe and USA.
For the USA it is estimated the 85 in older segment of the population will triple from 5.4 million to 19 million by 2050 and the correlation to the lifetime risk of undergoing a single operation for incontinence by age 80 is estimated to be 11.1%.
About 10-20% of these women become symptomatic over 70 years of age and about 10% of them undergoes surgery.
Comorbidities
Other reported risk factors for incontinence include comorbidities such as diabetes mellitus,
obesity,
parity and prior hysterectomy.
Genetics
Also quantitative and qualitative differences in collagen may contribute to pelvic floor dysfunction.
Connective tissue disorders such as Marfan syndrome and Ehlers Danlos syndrome have been linked to increased prevalence of incontinence and prolapse.
In histologic studies,
women with pelvic organ prolapse have been shown to have more type III collagen in pelvic floor connective tissues relative to other collagen subtypes and differences in the regeneration of elastin fibers.
Other studies have shown that women with pelvic organ prolapse and stress urinary incontinence have levator ani and periurethral muscle denervation and decreased neuropeptide activity.
Because these are mostly cross sectional studies,
it is unclear whether these histologic differences represent causes of prolapse and incontinence or subsequent effects of the disorder.
Gene expression has been found to be different in the levator ani muscles of women with prolapse,
compared with controls.
In addition,
a significant family history of hernias in men and women seems to be associated with symptoms of pelvic organ prolapse.
However,
in a twin study by Altman and colleagues,
genetic effects seemed to contribute to stress incontinence and pelvic organ prolapse,
but the influence of environmental factors was also substantial.
Endocrine factors
The role of hormone therapy on incontinence symptoms has been evaluated,
too.
Using data from the WHI,
Hendrix and colleagues reported that menopausal hormone therapy increased the incidence of all types of urinary incontinence at 1 year among women who were continent at baseline.
Ethnicity
Some authors reported that there is also a difference of prevalence of prolapse and incontinence due to effect of race and ethnicity: Dooley and colleagues found that white and Mexican American women had most double prevalence rates for stress incontinence compared with blacks,
but blacks had a higher rate of urge incontinence; Thom and colleagues found that the prevalence of all types of incontinence was highest in Hispanic women (36%),
followed by white (30%),
black (25%) and Asian American (19%) women; whereas Nygaard and colleagues found no differences among different races.
DIAGNOSIS
Evaluation of patients affected by pelvic floor disorders starts with clinical examination.
However,
clinical examination may be frequently unremarkable.
Also,
it may be unable to quantify clearly the entity of prolapse.
Thus,
an accurate pre-operative imaging evaluation is crucial.
ANATOMY
The pelvic floor is an anatomical structure,
which plays as a support to female perineum.
It is compound by muscular and fascial components: the first ones maintain the pelvic muscular tonus,
hindering gravity and the occasional increase of abdominal pressure,
while the endopelvic fascia,
a fibrous connective layer that connects the uterus and the vagina to the pelvic walls,
helps to increase pelvic floor stability.
Its anterior part is named pubo-cervical fascia and connects the anterior vaginal wall to the pubis,
thus increasing the support to the vagina.
Posteriorly,
the endopelvic fascia is named rectovaginal fascia.
The central portion of perineum is made by several support structures,
such as the endopelvic fascia,
the external anal sphincter,
the urogenital diaphragm,
and pubo-rectal muscles.
A crucial part of the pelvic floor is the levator ani muscle,
made by the iliacus- and pubo-coccigeal,
and the pubo-rectal muscles.
The last one is a fundamental component of the anal sphincter.
The ano-rectal junction is given by the intersection between the distal part of the rectum and the anal canal,
while the ano-rectal angle is given by the intersection of the posterior distal wall of the rectum and the central axis of the anal canal (this angle varies during contraction or resting of pubo-rectal muscles).
The contraction of the levator ani muscle closes the uro-genital hiatus and compresses the urethra,
the vagina,
and the ano-rectal junction towards the pubis.
From a clinical point of view,
the pelvic floor is divided into three compartments: the anterior,
that includes bladder and urethra,
the median,
including the uterus,
the cervix,
and the vaginal dome,
and the posterior,
that contains the rectum and the anal canal.
PATHOLOGY
Pelvic organ prolapse is defined by the ICS as the descent of one or more of: the anterior vaginal wall,
the posterior vaginal wall,
and the apex of the vagina or vault.
Currently,
most epidemiologic studies define prolapse based on examination or patient symptom report,
but not both.
Two studies from the Women's Health Initiative (WHI) including women in the United States aged 50 to 79 years reported the prevalence of any degree of prolapse (grades 1–3) based on examination to be 41.1%.
The prevalence of cystocele was 24.6% to 34.3%,
rectocele was 12.9% to 18.6%,
and uterine prolapse was 3.8% to 14.2%.
Two ancillary studies from a midwestern site for the WHI measured prolapse based on the Pelvic Organ Prolapse Quantification (POPQ) examination and used a more clinically useful definition of prolapse at or beyond the hymen.
They
reported the prevalence of prolapse to be 23.5% to 49.4% during a 4-year follow-up period.
These studies did not consider patient symptoms.
Typically,
pelvic floor dysfunctions are classified according to their anatomical location: affecting the anterior,
the median,
or the posterior compartment.
Overall,
the degree of prolapse is regarded as mild (lower than 3 cm in respect to the pubo-coccigeal plane),
moderate (between 3 and 6 cm),
and severe (more than 6 cm).
Anterior pelvic floor descent under the level of pubic simphisis is defined as cystocele.
This condition can determine different degrees of urinary disturbances.
Cystocele implies inferior and posterior dislocation of the uro-genital hiatus,
the uterus,
the vagina,
and the ano-rectal junction.
When cystocele occurs,
the anterior vaginal wall bulges and may promote the prolapse of the vaginal mucosa.
The anatomical supports of the uterus and the vagina that stabilize the median compartment are the uterosacral ligament,
the pubo-cervical fascia (that connects the lateral parts of the vagina to the pelvic walls) and the recto-vaginal fascia that connects the posterior aspect of the vagina to the perineal body,
so the dysfunctions that affect the median compartment are the uterine and the vaginal prolapse.
These entities are defined as a descent of the uterus or the vagina,
respectively,
under the pubo-coccigeal plan.
When uterine prolapse occur,
the cervix is translates along the vaginal canal,
that is usually shortened and more horizontal.
The dysfunctions that affect the posterior compartment are the rectocele,
the invagination and rectal prolapse and the enterocele.
a) rectocele: it is a bulging of the ano-rectal wall with rectal protrusion,
due to laxity or rupture of the supporting systems and laxity of the endopelvic fascia.
b) invagination and rectal prolapse: these conditions imply the inversion of the rectal wall,
the mucosa,
and the muscular wall.
c) enterocele: it is the herniation of peritoneum and bowel loops in the recto-vaginal space through the proximal third ot the vagina.
It may contain ileal loops,
a portion of sigma,
or peritoneal fat.
0 |
no prolapse is demonstrated |
1 |
the most distal portion of the prolapse is more than 1 cm above the level of the hymen |
2 |
the most distal portion of the prolapse is 1 cm or less proximal or distal to the hymenal plane |
3 |
the most distal portion of the prolapse protrudes more than 1 cm below the hymen but protrudes no farther than 2 cm less than the total vaginal length (for example,
not all of the vagina has prolapsed) |
4 |
vaginal eversion is essentially complete |
POP-Q classification of prolapse