Pelvic Prolapse

Introduction

Pelvic organ prolapse is a condition in which the pelvic organs are displaced and they protrude by varying degrees into the vaginal canal (ACOG). Affected organs can include the urethra, bladder, rectum, small bowel, uterus, or more commonly, a combination of these pelvic organs. Approximately, 300,000 prolapse surgeries are performed annually in the United States, with an estimated cost of over $1 billion.1 Several series have estimated that approximately 30–40% of women develop pelvic organ pro- lapse,2-4 and the lifetime estimate of surgical risk reaches 11–12% by 80 years of age.5,6

In the last few years, this rapidly progressing field has benefited from large-scale studies conducted worldwide, and notably in the United States by the accomplishments of the Pelvic Floor Disease Network (PFDN) of the National Institutes of Health (NIH). Because recurrence is unfortunately common after corrective surgery, with rates approaching 30%, many new techniques using a variety of reinforcing meshes have emerged.5 A recent FDA warning (October 2008) has reminded patients and physicians alike in cautiously employing mesh until adequate safety and efficacy records are established in randomized trials. While techniques of vaginal repair continue to evolve, newer advances in minimally invasive procedures have become increasingly used widely, with the most recent introduction being the robot. This chapter

highlights current areas of controversies and the practical progresses made recently in the field of POP with an emphasis on clinical diagnosis and surgical repair.

Epidemiology

Many factors have been identified as contributing to the development of pelvic organ prolapse, including parity, race, and age (Fig. 34.1). Other medical conditions which are associated with abdominal straining, such as chronic obstructive pulmonary disease and chronic constipation or diseases with connective tissue abnormalities, such as Ehler–Danlos syndrome and Marfan’s disease, can lead to greater risk of prolapse.

Prolapse in African American women is less common, while Hispanic females seem to have the highest risk for uterine prolapse.8 Asian American women are found to have the highest rates of anterior and posterior compartment prolapse. A nationwide concern, the trend in obese and overweight adults is increasing. Not only has weight been associated with development of both urge and stress incontinence, but overweight and obese females have been found to have higher risks of prolapse progression as well. Whereas weight loss has been associated with improvement in incontinence, this has not been demonstrated to be true with pelvic organ prolapse.2,11 Family history plays an important

Figure 34.1. Model for the develop­ ment of pelvic floor dysfunction in women (reprinted from Bump and norton7. copyright 1998.With permission from Elsevier).

role in many diseases. Positive family history for prolapse was noted in 78% of patients with severe prolapse and 50% of patients with mild prolapse in a study of patients presenting for routine gynecologic care.12 However, a Swedish twin study examining for the presence of genetic factors in the development of stress incontinence and prolapse noted that genetics may have a contributory role, but that environmental factors remain a strong determinant in the development of prolapse.13 Occupation may also play a role in prolapse. Several studies have found an association between lower income and less education, with laborers and factory workers having high incidence of severe pelvic organ prolapse.14 Prior surgery also plays a role with patients having had a previous hysterectomy, particularly by vaginal approach, or prolapse repair at greater risk for developing prolapse.15

The strongest associations have been found with advancing age and increased parity. Higher parity confers an 11-fold greater risk in the development of prolapse.16 Larger babies and number of vaginal deliveries contributed greatly to the presence of prolapse.3,17 These changes are suspected to be the result of the trauma that occurs during childbirth, characterized by pudendal nerve injury and injury to the muscles, tissues, and nerves of the pelvic floor and perineal body.

Anatomy and Pathophysiology

The pelvic cavity can be divided into anterior, posterior, and apical compartments with respect to the uterus and vagina. The support of the pelvic organs is a result of a combination of the pelvic floor musculature, fascial supports, and suspensory ligaments. The fascial supports and suspensory ligaments are condensations of peritoneum and connective tissues that attach the uterus, cervix, vagina, and urethra at different locations to the fascia of the pelvic sidewall and sacrum, thereby providing distinct levels of support (Fig. 34.2). The uterosacral and cardinal ligaments insert onto the cervix and upper vagina, comprising support at Level I. These ligaments prevent downward descent of the uterus and cervix and are responsible for apical support after hysterectomy. Tears or weakness in Level I support can result in uterine descent or vaginal vault prolapse and apical enterocele. Level II support is comprised of fascial attachments inserting on the midportion of the vagina and urethra, which extend laterally to the obturator internus fascia of the pelvic sidewall at the white line, or arcus tendineus fascia pelvis (ATFP). The lower vagina and urethral tissues are directly attached to surrounding structures, including the perineal body and rectovaginal septum, as Level III support. A defect in Level II or III support results in anterior and/or posterior vaginal wall prolapse, clinically

467

PElvic ProlaPsE

III II I

Ischial spine & sacrospinous ligament

Levator ani

Pubocervical fascia Rectovaginal fascia

weakness and increased flexibility of pelvic tissues, thereby predisposing to prolapse.20,21 Additionally, lower elastin expression and altered synthesis has been seen in the vaginal epithelium and uterosacral ligaments.22,23 Bioengineering of frozen/thawed and fresh vaginal tissues now permits to better understand the deformation of these aging tissues compared to age-comparable controls and to design finite element models of the vaginal wall from which newer reinforcing tissues (biocompatible mesh, tissue engineering) will be developed.24-26

Evaluation and Diagnosis

Figure 34.2. levels of vaginal support (reprinted from delancey et al.18 With permission from Elsevier).

evident as cystocele, rectocele, posterior enterocele, or a combination. The endopelvic fascia and levator ani muscles insert on the perineal body, lifting and supporting the rectum. Detachment or weakness here will produce a mobile and bulging perineum with straining,termed perineocele. Straining can widen the genital hiatus, further decreasing support to the anterior, posterior, and apical compartments, thereby worsening the degree of concomitant prolapse.

The biomechanical properties of connective tissue play an important role in determining the strength of the supporting ligaments and fascia. Smooth muscle, collagen, and elastin are components of connective tissue that impart strength and flexibility to the pelvic fascia and musculature, allowing for changes during pregnancy and childbirth. Dysfunction and alteration of these components are suspected to be contributing factors in the development of prolapse. Surgical biopsies of vaginal epithelium from patients with prolapse have been found to have significantly decreased amounts of smooth muscle in the muscularis layer with increased rates of apoptosis when compared to patients without prolapse.19 The tensile strength of tissues is the result of its collagen content, with type I collagen primarily responsible for strength and type III collagen responsible for elasticity of the tissues. Alterations in the amount and structure of collagen or in the ratio of types of collagen in pelvic and vaginal tissues account for the

Women with prolapse may complain of a variety of symptoms, including vaginal pressure or fullness, lower back or abdominal pain, incomplete emptying or urinary retention, stress incontinence, constipation or fecal incontinence. Patients with severe pelvic organ prolapse may complain of a vaginal bulge or feeling that something is “falling out” of the vagina. There is no consistent correlation between prolapse symptoms and physical exam findings, other than prolapse 0.5 cm or more beyong the hymen is strongly correlated with bulging symptoms.27

The two most employed systems for clinical examination and grading prolapse are the BadenWalker “half-way” system and the Pelvic Organ Prolapse Quantification (POP-Q). In recent literature, as a result of attempting to reproduce and standardize prolapse grade, the POP-Q has become the predominant grading system. It is a complex system that can be initially challenging to incorporate into practice,but provides detailed information about each compartment that can be useful in patient follow-up.

The Baden-Walker half-way scoring system was introduced in 1972 and consists of a series of stages to quantify vaginal prolapse. It is easy to learn and use, and has good interexaminer reliability. The maximal protruding segment is measured during straining or standing with the reference point being the hymen.

Stage I: the cervix, vaginal apex, anterior or posterior bladder wall descends half-way to the hymen.

Stage II: the cervix, vaginal apex, anterior bladder or posterior wall extends to the lower vagina, but not beyond the hymen.

Stage III: the cervix, vaginal vault, anterior or posteriorbladderwallextendbeyondthehymen, but is less than half-way completely prolapsed.

Stage IV: the cervix, vaginal vault, anterior or posterior bladder wall extend beyond the hymen, and is more than half-way completely prolapsed.

The Pelvic Organ Prolapse Quantification (POP- Q) system was developed by the International Continence Society (ICS) as an international tool to objectively describe, quantify, and stage pelvic support in women.28 It divides the vagina into six regions or points measured in centimeters with the reference point being the hymenal ring, consistent and easily identifiable structure that is assigned a measurement of 0. Measurements that are proximal to the hymen are distinguished by negative numbers; likewise, measurements that are distal to the hymen are given positive numbers.Additionally, the genital hiatus, the perineal body, and the total vaginal length are measured to complete the nine points of the system (Figs. 34.3 and 34.4).

Aa: a point in the midline of the anterior vaginal wall that is 3 cm from the hymen

Ba: the point on the anterior vaginal wall which represents the most dependent or prolapsed segment

D

Aa

Bp

Ap

TVL

GH

PB

Figure 34.3. Pelvic organ prolapse quantification (PoP­Q) scheme.six points (aa,ap,Ba,Bp,c,and d) are labeled.gH repre­ sents the genital hiatus, PB represents the length of the perineal body, and tvl represents the total vaginal length (reprinted from Bump et al.28 copyright 1996. With permission from Elsevier).

468

Practical Urology: EssEntial PrinciPlEs and PracticE

Figure 34.4. vaginal vault prolapse (complete eversion). according to the PoP­Q classification, aa (point in the midline of the anterior vaginal wall that is 3 cm from the hymen) is approxi­ mately 3 cm beyond the hymen.ap (a point in the midline of the posterior vaginal wall that is 3 cm from the hymen) is also 3 cm beyond the hymen.Point c (the point which represents the most distal surface of the cervix or the vaginal cuff) is approximately 9 cm beyond the hymen. Because point c also represents the most distal prolapsed segments of the anterior and posterior vaginal walls, points Ba and Bp are also assigned values of +9.

Ap: a point in the midline of the posterior vaginal wall that is 3 cm from the hymen

Bp: the point on the posterior vaginal wall which represents the most dependent or prolapsed segment

C:the point which represents the most distal surface of the cervix or the vaginal cuff

D:the point which represents the posterior fornix, omitted if the cervix is absent

GH: measured from the external urethral meatus to the midpoint of the posterior hymenal ring

PB: measured from the midpoint of the posterior hymenal ring to the midpoint of the anus TVL: measured from the hymen to the cervix or vaginal apex in a reduced state