PELVIC FLOOR DYSFUNCTION

Transcription

1 gastrointestinal tract and abdomen PELVIC FLOOR DYSFUNCTION Michael A. Valente, DO, FACS, FASCRS, and Tracy L. Hull, MD, FACS, FASCRS One of the most complex and potentially frustrating groups of patients that we treat are those afflicted with pelvic floor dysfunction. Pelvic floor dysfunction encompasses a broad spectrum of disorders and symptoms, including pelvic organ prolapse, fecal incontinence, dysfunctional bowel and/ or bladder evacuation, urinary incontinence, and chronic pain. The severity and the full scope of pelvic floor dysfunction vary widely. Challenges in treating these individuals are due, in part, to inconsistent definitions and diagnostic criteria along with an underreporting of symptoms coupled with the complexities in understanding the underlying pathophysiology. Pelvic floor dysfunction is a multisystem process, with concurrent disorders occurring at the same time. Therefore, a multidisciplinary team approach for evaluation and treatment is mandatory as isolated evaluation and potential surgical correction of only one component of what is a multisystem process may lead to poor outcomes. This review aims to survey pelvic floor dysfunction, with an emphasis on the evaluation and treatment of the posterior pelvic floor. Incidence, Prevalence, and Etiologic Factors In the United States, it has been reported that up to 25% of women have at least one pelvic floor disorder, and the incidence increases with age, parity, and obesity. 1 4 The exact prevalence of the great majority of pelvic floor disorders is unknown due to underreporting and a lack of consistent, standardized definitions. For urinary incontinence, reported rates range from 9 to 22%. 3,4 The reported prevalence of fecal incontinence varies in the literature between 2 and 24% depending on the severity and frequency used to define the problem, and for pelvic organ prolapse, the true prevalence is unknown due to the aforementioned reasons. 4 6 One of the most important factors in the development of pelvic floor dysfunction is obstetric trauma. The development of both pelvic organ prolapse and incontinence can be precipitated by vaginal delivery, with anal sphincter disruption being the major cause of fecal incontinence. Sultan and colleagues found an association between fecal incontinence and episiotomy, with a threefold increase in incontinence in women who underwent an episiotomy. 7 Additionally, pudendal nerve injury at the time of childbirth has also been associated with fecal incontinence after vaginal delivery. 8,9 Other significant risk factors for fecal incontinence after vaginal birth include delivery of high birth weight infants, parity, and a high degree of perineal injury. Women who experience a recognized third-degree tear during delivery have a 30 to 60% incidence of developing fecal incontinence, and a third-degree tear with forceps delivery carries a risk of incontinence between 13 and 80% in various studies. 4,10 Obesity is another significant risk factor for pelvic floor dysfunction, and in a study from Whitcomb and colleagues, obese individuals with a body mass index (BMI) greater than 30 had a 46% prevalence of pelvic floor dysfunction 2015 Decker Intellectual Properties Inc compared with nonobese individuals. 11 The authors also noted that as BMI increased, so did the prevalence of pelvic floor dysfunction (a BMI > 37 had a 53% prevalence, and a BMI > 45 had a 57% prevalence). Similarly, Hendrix and colleagues found that morbidly obese patients (BMI > 45) have a significant increase in rectocele (75%), uterine prolapse (40%), and cystocele (7%) over nonobese individuals. 12 Hypotheses of increased pelvic floor dysfunction in obese individuals have been attributed to an increase in the frequency of bowel movements and to increased abdominal pressure. 13,14 Highlighting that obesity increases pelvic floor dysfunction, Wasserberg and colleagues showed that morbidly obese women (mean BMI 49.3) with fecal incontinence who underwent weight loss surgery decreased their prevalence from 87% preoperatively to 68% postoperatively. 15 Increasing age has been attributed to increasing pelvic floor dysfunction in multiple studies. Fecal and urinary incontinence as well as pelvic organ prolapse are all increased in elderly individuals. Urinary incontinence has been estimated between 30 and 50% in epidemiologic studies for elderly females, and fecal incontinence rates range from 9 to 17% in individuals over the age of 75. 4,16,17 Additionally, in a study by Olsen and colleagues, the overall lifetime risk of having an operation for pelvic organ prolapse by age 80 is 11.1%. 18 Other, less common factors may preclude individuals to pelvic floor dysfunction, such as a history of anorectal or urogynecologic surgery, congenital pelvic malformations, neurologic conditions (multiple sclerosis, spinal cord injuries, and diabetes mellitus), pelvic organ cancer, pelvic radiation, depression, anxiety, and poor physical functioning [see Table 1]. Clinical Evaluation To properly evaluate patients with pelvic floor dysfunction, a multidisciplinary team approach is recommended. Colorectal surgeons along with urologists, gynecologists, Table 1 Potential Contributing Factors in the Development of Pelvic Floor Dysfunction Increasing age Parity Obesity Trauma Obstetric Postsurgical Congenital malformations Neurologic conditions Multiple sclerosis Spinal cord injuries Diabetes mellitus Pelvic cancer Radiotherapy Psychological DOI /

2 gastro pelvis floor dysfunction 2 radiologists, physical therapists, psychiatrists, and specialist nurses should all be involved in the workup and care of these patients. Pelvic floor disorders in one compartment have a high propensity to coexist with pelvic floor disorders of the other compartment, and isolated evaluation of one can lead to the diagnosis and correction of only one problem of a potential compartmental process. The pelvic floor evaluation begins with a detailed history and examination, which will then lead to the appropriate tests to be performed. history The history is the first and possibly the most important tool in evaluating patients with a pelvic floor dysfunction. A complete past medical and surgical history should be obtained, including an obstetric history. Details of the patients presenting symptom(s) should include onset, duration, frequency, severity, and any exacerbating or relieving factors. 3 The current medication regimen, particularly medications that can have an effect on intestinal transit and anorectal function, should be obtained along with start dates in relation to the onset of symptoms, which may provide a causal relationship. Bowel function patterns need to be documented in detail, including frequency of evacuation, length of time for evacuation, straining, urgency, anorectal pain, rectal bleeding, posturing and digitations, and any trends over time. The consistency of the patient s stool will influence the severity of constipation or fecal incontinence; thus, evaluation with guides such as the Bristol Stool Scale have been developed to help grade stool consistency. 3 Other validated scoring systems have been developed to add to the clinical history and include the Cleveland Clinic Continence Score, St. Mark s Incontinence Score, American Society of Colon and Rectal Surgeons Fecal Incontinence Severity Index (FISI), and Fecal Incontinence Quality of Life Score (FIQL), among many others. 3,19 Patients presenting with constipation can have varied symptoms, and classification is quite variable throughout the literature. Functional constipation patients can be broadly divided into those with normal transit, slow transit, evacuatory dysfunction (obstructed defecation), or mixed dysfunction. For patients with constipation, the investigations should be guided by the symptoms garnered from the history. A recent change in bowel habits or rectal bleeding warrants consideration for a colonoscopy. In patients presenting with fecal incontinence, the type should be delineated: passive incontinence involuntary defecation without awareness or urge incontinence the inability to defer stool in spite of active attempts to retain bowel contents. 3 Passive incontinence is likely due to internal anal sphincter dysfunction or a lack of proper sensation, and urge incontinence seems to result from an inability of the rectum to store stool. Patients may have a combination of these two, and a careful history is imperative to understand what is happening at the time of defecation. Most patients with severe fecal incontinence require endoanal ultrasonography (EUS) to define the anatomy and physiologic testing to define function. 3 One of the most important aspects of the history is to define the most troubling aspect of the patient s problem and how it affects his or her quality of life. The answers to these questions will help guide any investigational studies and, potentially, therapeutic options. physical examination Following a detailed history, a general physical examination should be undertaken on all patients looking for the presence of any coexisting systemic disease. A BMI should be recorded as the patient s weight may influence symptoms, 3,20 and an abdominal examination documenting any previous surgical incisions should be carried out as well. Pregnancy testing on all appropriate female patients should also be performed. The perineum, vagina, anal canal, and rectum are then examined in a stepwise fashion. A visual inspection of the perineum is of great benefit and may reveal various conditions such as scarring, fecal soiling, excoriations, erythema, anal sphincter shape, perineal body bulk, hemorrhoidal disease, skin tags, overt signs of inflammatory bowel disease (IBD), external fistulous openings, and evidence of previous anorectal surgery or rectal prolapse. 3 Next, the patient is asked to strain (Valsalva maneuver) to help determine and assess abnormal perineal descent, uterine prolapse, or rectal prolapse. Full-thickness rectal prolapse (procidentia), however, is best evaluated after the patient has taken an enema and strains on the toilet or commode. The use of an illuminated, handheld mirror to view the procidentia (and other anorectal pathology) while in the sitting position has been described by Slezak, 21 among others, and may enhance visualization. Digital rectal examination (DRE) of both the anorectum and vagina should be performed at rest and strain. Assessment should note any obvious anorectal pathology, such as a mass, rectocele, and resting and squeeze tone (although this may correlate poorly with manometric and ultrasound assessment). 8,22,23 The levator ani/puborectalis muscle can also be assessed on DRE with evaluation of both the strength and function of these muscles, along with any tenderness on direct palpation, indicating a possible pelvic pain disorder. Stool load and consistency should be documented, as well as if any fecal impaction is present. Lastly, proctoscopy and rigid or flexible sigmoidoscopy should be performed to exclude any neoplasia or inflammatory conditions, and this may also help diagnose hemorrhoids, solitary rectal ulcer, or other diseases. investigations Often the history and physical examination will help correctly identify the underlying anorectal disorder in pelvic floor dysfunction patients. However, in patients who may be considered for a surgical procedure, functional evaluation and imaging are an important adjunct. Many tertiary centers that deal with complex pelvic dysfunctional disorders have a dedicated pelvic floor unit with appropriate personnel to administer and interpret these tests accurately. It is important to remember that testing is a guide and that the entire clinical picture, including the history and physical examination and other testing, needs to be taken together. Some people may have abnormal testing and no symptoms, whereas others will have normal testing and severe symptoms.

3 gastro pelvis floor dysfunction 3 Additionally, basic blood tests should be obtained, including thyroid studies and calcium levels, which may help evaluate any metabolic causes of functional bowel disorders. A pregnancy test should also be obtained, when appropriate, before any further testing is performed. Colonoscopy should be obtained to rule out any functional etiologies, malignancy, IBD, or microscopic colitis. Stool microscopy and cultures may be obtained for a potential cause of diarrhea, and other disease processes, such as celiac disease, should be ruled out with the aid of a gastroenterologist. An overview of anatomic and physiologic tests for evaluating the pelvic floor is summarized here [see Table 2]. physiologic assessment Anorectal manometry gives a quantitative assessment of the anal sphincter complex and measures the pressures in the anal canal and distal rectum. Manometry is one of the most widely used and accepted investigations to measure the function of the external anal sphincter (EAS) and the internal anal sphincter (IAS) and is commonly performed to evaluate patients with fecal incontinence. Manometry can give detailed information in regard to resting, squeeze and strain anal sphincter pressures, rectoanal inhibitory reflex (RAIR), rectal sensation and compliance, anal canal length, and balloon expulsion tests. Besides fecal incontinence, anal manometry can be used as a screening tool for obstructed defecation syndrome (nonrelaxation/paradox of the puborectalis), Hirschsprung disease (absence of RAIR) and may be used during biofeedback therapy to assess response. 24 Anal manometry is performed in the office setting, and a variety of catheters and systems are used to perform the test, including water-perfused, microballoon, or solid-state pressure-sensing catheters [see Figure 1]. Due to variations in technique, equipment, and a lack of methodological standardization, normal ranges vary between individual Figure 1 Anal manometry apparatus. institutions. The test should be performed in a comfortable and private environment with minimal personnel present. The patient is placed in the left lateral position, and the catheter is lubricated and inserted into the anus and rectum to the 6 cm mark. The catheter is then extracted at 1 cm intervals, recording anal canal pressures in the resting state and then after voluntary contraction of the sphincters (station or pull-through technique). The resting pressure reflects the IAS as this muscle may constitute 55 to 85% of the resting tonic activity of the anorectum. Other components of resting pressure include anal cushion (hemorrhoidal complexes) in up to 15% and the EAS in 15 to 30%. The maximum resting pressure is the highest resting pressure in the resting state in the highpressure zone of the anal canal. The squeeze pressure Table 2 Anatomic and Physiologic Tests for Pelvic Floor Dysfunction Test Indication(s) Modality Measured Physiologic Anorectal manometry Fecal incontinence, nonrelaxation of pelvic floor, Hirschsprung disease Anal sphincter function, anorectal sensation, rectoanal reflexes, rectal motor function Pudendal nerve terminal motor latency (PNTML) Pudendal nerve injury or neuropathy PNTML Electromyography (EMG) Anatomic Endoanal ultrasonography Endoanal magnetic resonance imaging (MRI) Anatomic and physiologic Dynamic defecography Dynamic MRI Anal sphincter injury, biofeedback, imperforate anus Fecal incontinence, fistula disease, tumors Fecal incontinence, fistula disease, tumors Obstructed defecation, pelvic organ prolapse Obstructed defecation, pelvic organ prolapse Marker study Constipation Global transit time Adapted from Mellgren. 24 Muscle activation, motor unit potential and fiber density (needle EMG) Assessment of the external anal sphincter (EAS) and internal anal sphincter (IAS), pelvic floor, and rectum Assessment of the EAS and IAS, pelvic floor, and rectum Rectal evacuation and dynamic assessment of the rectum and vagina/bladder Rectal evacuation and dynamic assessment of the pelvis

4 gastro pelvis floor dysfunction 4 reflects the striated EAS and can be calculated as the maximum squeeze pressure, which correlates to the highest pressure achieved in the high-pressure zone. Patients with decreased squeeze pressures may have an EAS injury or neurologic damage. Both the mean resting and squeeze pressures are calculated by averaging all of the results across the anal canal length. Our institution defines normal mean resting pressure greater than 40 mm Hg and mean squeeze pressure greater than 100 mm Hg [see Figure 2]. The RAIR on anal manometry is defined as a transient decrease in resting anal pressure (IAS) greater than 25% of basal pressure in response to rapid inflation of a rectal balloon with subsequent return to baseline. The RAIR is mediated via the myenteric plexus and is modulated by the spinal cord Normally, rectal distention will result in a brief increase in tone followed by inhibition of the tonic activity of IAS, which allows for muscle relaxation. This reflex also facilitates rectal emptying, which then allows for the sampling reflex to occur. The sampling reflex allows the anal canal to facilitate discrimination between gas and fecal material. The presence of an intact RAIR is dependent on an intact myenteric plexus and, thus, is not present in patients with Hirschsprung or Chagas disease. RAIR may also be absent after performing a low anterior resection, coloanal anastomosis, or ileal pouch-anal anastomosis. If the patient has a megarectum, the amount of volume in the balloon needed to distend the rectum to elicit the reflex will be needed, which may lead to false negative results. Rectal sensation and compliance can also be measured during manometry by intermittent balloon distention in the distal rectum while measuring responses. Measurements include the first sensation as the balloon is filled (rectal sensory threshold), the first urge, and the maximum tolerated volume. Rectal compliance is then calculated and reflects the ability of the rectum to accommodate to different volumes without altering pressures. Low rectal compliance may be seen in conditions with inflammation of the rectum or radiation damage, whereas high compliance may be seen in patients with diabetes mellitus, megarectum, or other neurogenic abnormalities. Additionally, rectal sensory threshold has been shown to be valuable in determining if biofeedback therapy will be successful. 3,28 Nonrelaxation of the puborectalis muscle (paradoxical contraction) during straining can also be detected during anal manometry. This condition is highlighted by inappropriate contraction of the levator muscle when straining, which may cause obstructed defecation. This is discussed in greater detail below. The rectal balloon expulsion test is an easy method to assess the evacuatory function of the rectum and provides a baseline test for defecatory function. A balloon is filled with water or air to 50 cc. The patient is asked to expel the balloon, and if he or she cannot, the balloon is filled to 100 cc. If the patient cannot expel the balloon in under 60 seconds, this may signify a pelvic floor dysfunction. Rectal balloon expulsion has been shown to have 90% sensitivity, and false negatives can be common. The utility of the test by itself is limited, but when used in conjunction with other anal physiology tests, it may assist in diagnosis. 29 neurophysiologic assessment Pudendal Nerve Terminal Motor Latency Pudendal nerve terminal motor latency (PNTML) measures the time it takes from stimulation of the pudendal nerve at the level of the ischial spine to lead to contraction of the EAS and provides electrophysiologic appraisal of the motor innervation of the pelvic floor muscles. 30,31 The pudendal nerve innervates the EAS, perineal musculature, anal canal mucosa, and perianal skin and carries both afferent and efferent information from S2, S3, and S4 nerve roots. The pudendal nerve travels laterally on the pelvic floor and exits the pelvis at the ischial spine into the Alcock (pudendal) canal. To perform the test, the pudendal nerve is stimulated intrarectally with an electrode attached to the index finger [see Figure 3]. Both the left and right sides are stimulated separately. The average latency of a normal pudendal nerve is 2.0 ± 0.2 milliseconds, and prolongation is indicative of nerve damage [see Figure 4]. PNTML has been questioned and remains controversial due to its low specificity and sensitivity. Given that the test evaluates only the fastest nerve fibers, incomplete nerve injuries can be missed. Some investigators have found abnormal PNTML to be helpful, especially with bilateral neuropathy as a predictor of poor outcome after sphincteroplasty for fecal incontinence, whereas other authors have seen no correlation. 32,33 The results can be helpful before sphincter repair or biofeedback and therefore should be used as a complementary tool in physiologic assessment of anorectal function. 34 Electromyography Anal electromyography (EMG) can be used to gauge the activity of the striated pelvic floor muscles and is used primarily to identify EAS function. 24,35,36 Surface EMG has been developed as a minimally invasive, well-tolerated technique that entails placing a patch electrode on the surface of the perianal skin or placing a sponge inside the anal canal [see Figure 5]. Nonrelaxing puborectalis is diagnosed by an abnormal high-amplitude pattern during straining, which mimics that seen during straining or coughing. 30 The surface electrodes are frequently used to measure external sphincter contraction and relaxation, whereas the anal plug is mostly used for biofeedback training. Patients with nonrelaxation of the puborectalis or fecal incontinence can use both audio and visual signals resulting from their sphincter and pelvic floor muscle contraction/relaxation to guide them during pelvic floor retraining/biofeedback. 24 Needle EMG was previously used to identify areas of sphincter injury by mapping the sphincter and/or to identify areas of denervation-reinnervation patterns indicative of nerve injury. Needle EMG involves inserting a needle into the external sphincter muscle at rest and during voluntary contraction. Single-fiber EMG is another modification that identifies muscle action potential from a single muscle fiber. Needle EMG is less commonly performed today due to the highly invasive, uncomfortable nature of the examination and the potential for infectious complications. Additionally, interpretation is highly specialized and is becoming increasingly unavailable at most centers. Furthermore, the clinical utility of needle EMG is quite limited, and it has been shown

5 gastro pelvis floor dysfunction 5 Pressure studies Acl: 2 cm (Normal: male = 4 5 cm/female = 3 4 cm) Pmrp Pmrp Pmsp Lmrp Rmrp Lmsp Rmrp Rmsp 15 Amrp AVG. RESTING PRESSURE 20.5 mm Hg Normal: > 40 mm Hg 40 Amsp AVG. SQUEEZE PRESSURE mm Hg Normal: > 100 mm Hg Volume studies Rectal anal inhibitory reflex: ml Normal: ml (If neg. = absent myenteric plexus) Volume first sensation: 20 ml Normal: ml Volume first urge: 20 ml Normal: ml Max. tolerated volume: 100 ml Normal: ml Compliance: 5 ml/mm Hg Normal: 5 15 ml/mm Hg Defecometry studies Patient squeezes Normal: Intrarectal < Anal canal pressure Intrarectal squeeze mm Hg Anal canal squeeze mm Hg EMG squeeze 3/5 Normal: 3/5 Defecometry results: Balloon expulsion: Patient strains Normal: Intrarectal > Anal canal pressure Intrarectal strain mm Hg Anal canal strain mm Hg EMG strain 1/5 Normal: 1/5 Balloon volume: Nerve studies Biofeedback studies Pntml rt: 2 Pntml lt: 2 Normal: 2.0 ms Single fiber result Bio IR pressure Bio AC pressure Biofeedback result: Bio EMG Impression Figure 2 Anorectal physiology report for a patient presenting with fecal incontinence. Both resting and squeeze pressures are low and are more pronounced anteriorly. AC = anal canal; Acl = anal canal length; Amrp = anterior mean resting pressure; Amsp = anterior mean squeeze pressure; EMG = electromyography; IR = intrarectal; Lmrp = left mean resting pressure; Lmsp = left mean squeeze pressure; Pmrp = posterior mean resting pressure; Pmsp = posterior mean squeeze pressure; Pntml lt = pudendal nerve terminal motor latency left; Pntml rt = pudendal nerve terminal motor latency right.

6 gastro pelvis floor dysfunction 6 anatomic assessment Figure 3 Pudendal nerve-stimulating electrode mounted on the examiner s gloved finger. that there is poor correlation between anorectal physiology, severity of EMG changes, and degree of fecal incontinence. 37 It has also been shown that mapping of the EAS by anal ultrasonography is more sensitive and subject to less sampling error than EMG. 38 Nonetheless, there are still physicians (mostly neurologists) who can administer this test and obtain helpful information. Endoanal Ultrasonography EUS is a highly reliable modality that provides information on the integrity of the anal sphincter complex. In experienced hands, EUS has a very high sensitivity and specificity for detecting anatomic defects in both the IAS and EAS. 24,39 Both anal sphincters can be assessed for length, thickness, and any asymmetry or defects. EUS has been validated, and a high correlation exists between the ultrasound finding and intraoperative, histologic, and physiologic findings. 7,40 42 The test is tolerated well by patients, plays a pivotal role in the workup of patients with fecal incontinence, and is the preferred method of imaging at many centers, including ours. Circumferential assessment of the anal canal is made possible by a 360 rotating transducer. The transducer can be either a 7 or 10 MHz probe for two-dimensional (2D) units or a 13 MHz probe for three-dimensional (3D) machines [see Figure 6]. 3D EUS has become more widely available over the last several years and carries a similar sensitivity of detecting both EAS and IAS defects compared with 2D probes, but intraobserver variation is decreased, and diagnosis of pathology has been shown to be increased with the 3D models [see Figure 7]. 43 Our institution currently uses both 2D and 3D machines in our pelvic floor unit. Pudendal #1 Stimulus Left pundendal 50 µv/cm L. latency 1.8 ms Left PNTML response Right pundendal 50 µv/cm R. latency 3.2 ms Right PNTML response 2 ms ST LT RT 00:00 s 00:04 s 00:08 s 00:12 s 00:16 s 00:20 s 00:24 s Figure 4 Pudendal nerve terminal motor latency (PNTML) tracing. The right and left tracings are superimposed on each other. The large spike signifies the stimulus, and the muscle response is shown as the takeoff of the curve. The latency measurement is the time difference between the stimulus and muscle contraction. The left is normal at 1.8 ms, whereas the right side is delayed at 3.3 ms. Normal values are 2.0 ± 0.2 ms. LT = left; RT = right; ST = stimulus.

7 gastro pelvis floor dysfunction 7 Figure 5 Surface electrode electromyography. Prior to this test, patients may require an enema to clear the anorectum of any stool that may interfere with images due to artifact. Additionally, it is important to ensure that there is no preexisting anorectal pathology that may make the test painful or difficult, such as fissure-in-ano or anal stenosis. Most commonly, the test is performed with the patient in the left lateral position. After careful insertion of the lubricated probe, slow advancement combined with slow withdrawal is used to view all three levels of the anal canal (in modern systems, a crystal moves up and down along the transducer to acquire images while the probe is held still, which allows for higher quality images). 8 The anal canal is divided into three levels on EUS: upper, middle, and lower. The upper anal canal is defined by the presence of the puborectalis muscle; the middle canal has both external and internal sphincter muscles; and in the lower canal, only the most distal external sphincter fibers can be seen. On ultrasonography, tissue that is highly reflective reveals a hyperechoic (white) image, whereas poorly reflective tissues are hypoechoic (black). Thus, the IAS, composed of smooth muscle, has a high water content, which allows the ultrasound waves to easily penetrate through and appears black on the screen [see Figure 8]. 3 In the upper anal canal, the anatomic landmark is the highly hyperechoic, white, U-shaped puborectalis muscle [see Figure 9]. The puborectalis then blends into the EAS in the middle anal canal, which forms a complete concentric ring. The IAS in the middle canal also forms a complete ring and is maximally thickened in this area. In the lower anal canal, only the Figure 7 B-K Medical three-dimensional anorectal ultrasound equipment. EAS is seen, which represents the subcutaneous component of the muscle. Any injury to the sphincter complex is seen by a break in the muscular rings(s) [see Figure 10]. Perineal body measurements can also be obtained by measuring IAS EAS Figure 6 B-K Medical (Herlev, Denmark) ultrasound threedimensional anorectal probe type Figure 8 Two-dimensional sonogram from the middle anal canal. This ultrasound image represents normal, intact internal anal sphincter (IAS) (hypoechoic) and external anal sphincter (EAS) (hyperechoic).

8 gastro pelvis floor dysfunction 8 Puborectalis sphincter atrophy. MRIs can be accomplished by either endocoil or external phased array coil, with the endocoil not readily available in many centers. These two techniques are comparable in diagnosing external muscle atrophy and sphincter defects. 44 MRI and ultrasonography have been shown to be comparable to each other, and there is currentl y no consensus as to which test is superior; however, MRI is considerably more expensive. Many centers, including ours, routinely use EUS as the first-line imaging modality for anal sphincter complex pathology. anatomic and physiologic assessment Figure 9 Three-dimensional endoanal ultrasound view of the U-shaped puborectalis muscle. from the tip of the vaginal introitus (a finger can be placed into the vagina to delineate this point) through the thickness to the IAS. Normal perineal body measurement is approximately 12 mm, and values less than 10 mm are suggestive of sphincter injury. The presence of a defect should be correlated with the history and any physiologic findings. 8 Incidental defects are often found in patients without a history of fecal incontinence, and in other patients, the extent of the defect may not correlate with their symptoms. Magnetic Resonance Imaging Over the past two decades, magnetic resonance imaging (MRI) has gained acceptance and use to image both the pelvic floor muscles and the anal canal. In terms of anal sphincter anatomy, MRI is an excellent tool, especially for external Defecography Dynamic evacuation proctography (cinedefecography, defecography) was first introduced in the 1960s and is the first-line investigation of evacuatory dysfunction, with the ability to detect both morphologic and functional abnormalities. 8,30 This dynamic study requires opacification of the pelvic structures by instilling contrast into the rectum (and, often, oral, vaginal, and sometimes bladder contrast), which is then followed by simulation of evacuation on a special radiolucent commode. The test is performed in a fluoroscop y suite with the aid of video recording and freeze-framing during rest, during squeeze, and at strain. Defecography is performed on patients with fecal evacuation problems. Some centers use this test if full-thickness rectal prolapse is suspected in a patient with fecal incontinence, but rectal prolapse is best evaluated on a commode during the physical examination, as previously described [see Figure 11]. Defecography is useful in identifying mechanical etiologies of obstructed defecation such as rectocele, enterocele, and sigmoidocele [see Figure 12 and Figure 13]. Measurement of the anorectal angle (the angle between the longitudinal axis of the anal canal and the posterior wall of the lower part of the rectum) can also be measured with squeeze, rest, and Small bowel Sacrum Vagina Sigmoid Rectum Figure 10 Endoanal sonogram showing a defect in the external anal sphincter of approximately 90 to 100. Figure 11 Defecography showing normal anatomy.

9 gastro pelvis floor dysfunction 9 Rectocele Enterocele Figure 12 Defecography showing a significant rectocele and enterocele. strain, but our unit has not found these helpful. Likewise, perineal descent can be measured, but, again, we do not focus on this. The ability to quickly initiate defecation and fully empty the rectum is an important portion of this test. Some patients simply cannot evacuate their rectum, which may be caused by nonrelaxation of the puborectalis, Hirschsprung disease, Chagas disease, megarectum, or an undescribed rectal problem. Detection of a problem with rectal evacuation may only be ascertained during the cinedefecography portion of this test. Another use is to Sigmoidocele Figure 13 Defecography demonstrating a sigmoidocele. verify adequate rectal evacuation prior to performing a total colectomy with ileorectal anastomosis for slow transit constipation. The specific techniques used vary between centers, and adjustments may be made to elucidate the pathology in question. Regardless of technique, the environment must be suitable to allow patients to comfortably defecate and to replicate their defecation pattern. The number of personnel involved in the test should be kept to a minimum, and the patient s modesty and comfort are of the utmost importance during this sometimes stressful and embarrassing procedure. Patients must be coached prior to the test to strain vigorously when asked to defecate to optimally detect any abnormalities. The technique used at our institution includes a bowel preparation before the procedure followed by oral barium ingestion 1 to 2 hours before the procedure to highlight the small bowel and allow identification of a potential enterocele. The vagina and rectum are then filled with contrast via catheters. Liquid barium is initially instilled via a rectal catheter into the sigmoid followed by a viscous barium paste instilled into the rectum to replicate the consistency of stool. Barium is continuously instilled via the rectal catheter until the patient experiences a feeling of rectal fullness and a strong urge to defecate (or to a maximum of 200 ml of paste). Following the administration of all the contrast material, the patient then sits on a specialized radiolucent commode behind a screen, and fluoroscopy is performed in a lateral view. The patient is asked to relax, squeeze (pelvic muscle contraction), and then strain (maximally push without evacuation). Still images are taken, and the amount of descent can be measured from these data. Next, the patient is asked to pass the rectal contrast, and the resulting fluoroscopic images are video-recorded. There is a large amount of overlap in defecography findings between what is considered normal and abnormal, and all findings need to be considered in the setting of clinical symptoms. At our institution, the following findings are noted in the defecography report: delayed or incomplete rectal emptying, changes in the anorectal angle, anterior or posterior rectocele, sigmoidocele, enterocele, perineal descent, internal intussusception, and full-thickness rectal prolapse. Treatment options and strategies on each of these findings are reviewed below. Dynamic MRI MRI offers high-resolution evaluation of the entire pelvis and associated structures and has the unique ability to assess all three pelvic floor compartments (anterior, middle, and posterior) simultaneously, without the negative effects of ionizing radiation. Similar to defecography, contrast medium is placed (must be water soluble), and the same anatomic landmarks are used to measure descent and pelvic organ prolapse. Findings on MRI in regard to structure and function have correlated well with dynamic defecography; furthermore, MRI may be more sensitive in distinguishing rectal mucosal prolapse from rectal intussusception. 8 A major disadvantage of magnetic resonance defecography is that the patient is in a supine position, which is not physiologically appropriate, and certain findings, such as prolapse, may be missed. However, an open-design sitting

10 gastro pelvis floor dysfunction 10 MRI is also available, which overcomes many of the disadvantages of supine MRI. In the open configuration, the patient is sitting and represents a more normal defecatory position. These units are quite large and very expensive, which makes their availability extremely limited; hence, only a few specialized centers have them available for patient use. At our center, MRI and cinedefecography are complementary studies, but cinedefecography is used more commonly due to the more physiologic sitting position and because defecography is considerably less expensive than MRI. The increase in MRI in evaluation of defecatory dysfunction is increasing, however, and the decision of which modality to use depends on the close collaboration of the pelvic floor specialist and with the radiologist at individual institutions. Colonic Motility Transit Studies Although colonic motility is not strictly a pelvic floor problem, it is important to determine if patients have coexisting slow transit constipation in addition to obstructed defecation. Although colonic dysmotility is most common, gastric and small bowel motility disorders coexist as well. Patients with panintestinal dysmotility are the most challenging patients to treat with the fewest options and worst prognosis. 30 The most common test for colonic motility includes the ingestion of radiopaque markers to evaluate the passage of stool through the gut over time. Other available tests include colonic scintigraphy and colonic manometry, which are used at specialized centers mostly for research purposes because these tests are expensive, not readily available, and not standardized. 8 More recently, the SmartPill has been used to measure gastric emptying, small bowel transit, and large bowel transit. A wireless monitoring system is built inside a pill that measures temperature, intraluminal pressure, and ph, which is then recorded by a portable receiver. From these data, whole gut transit and colonic transit can be separated and calculated. The SmartPill has been compared with colonic scintigraphy and seems to be a promising tool to help diagnose motility disorders, but more studies are needed to prove its clinical utility. 24 Our unit does not routinely use this technology at this time. There have been several variations on the technique of colonic transit time, but all essentially evaluate the number of markers remaining in the colon on plain radiographs 5 to 7 days after marker ingestion. All patients before the test are instructed that the basis of the test is to determine how quickly digestive material moves through their intestines and that any and all laxatives, enemas, and suppositories cannot be used for the duration of the test. The technique used at our institution consists of the patient taking one to two marker capsules (24 to 48 radiopaque markers) on Sunday morning. The patient then has plain radiographs on Monday, Wednesday, and Friday mornings. The initial film on Monday serves as a crude gastric and small bowel motility test. If all of the markers are present in the colon on the first film, patients most likely have normal upper gastrointestinal motility. After the fifth day, 80% of the radiopaque markers should be expelled, and all should be expelled by the seventh day. If there is retention of 20% or more markers beyond the fifth day, the distribution of the markers becomes diagnostically important. If the markers are randomly scattered throughout the colon, this suggests slow transit constipation [see Figure 14]. However, if the markers show a predominance at the rectosigmoid junction, this may be more suggestive of a diagnosis of obstructed defecation [see Figure 15]. Management of Pelvic Floor Dysfunction The management of rectal prolapse, fecal incontinence, and constipation is discussed in other reviews. Included here are treatment strategies for the most common posterior pelvic floor disorders. rectocele A rectocele is a defect of the rectovaginal septum that facilitates herniation of the anterior rectum into the posterior vagina or surrounding perineal region [see Figure 16]. Rectoceles are very common and have been reported in up to 80% of women undergoing defecography [see Figure 17]. 45 These women are generally asymptomatic; thus, the majority of rectoceles are physiologically insignificant and require no medical or surgical intervention. However, if the bulge into the vagina is large, accumulation of stool in the defect may occur instead of being propelled out of the anal canal. This will often manifest itself as inability to empty the rectum during defecation, a feeling of vaginal or perineal fullness, or protrusion of tissue through the vaginal introitus during straining or activity. The exact etiology is unknown, but risk Figure 14 Colonic transit study, day 7. Distribution of markers scattered throughout the colon, indicative of slow transit constipation.

11 gastro pelvis floor dysfunction 11 Sigmoid Vagina Rectocele Figure 17 Defecography demonstrating a rectocele. Figure 15 Colonic transit study, day 7. Accumulation of markers at the rectosigmoid junction, indicative of obstructed defecation. factors such as parity and chronic straining may cause tearing and stretching of the rectovaginal support structures. 46 The patient who chronically strains in the setting of nonrelaxation of the puborectalis (paradox) may also play a large role in the pathogenesis of a symptomatic rectocele. Rectocele classification is based on radiographic parameters (size at maximum straining) and physical examination (degree of protrusion relative to the hymen). In constipated patients, it has been shown that only 10 to 20% of rectoceles are clinically significant as the cause of the obstructed defecation. 3 Rectoceles can be considered symptomatic (causing Figure 16 Rectocele. Protrusion of anterior rectal wall into posterior vagina (rectocele) (arrow). Reprinted with permission, Cleveland Clinic Cente r for Medical Art & Photography All Rights Reserved. obstructed defecation) when they are large (> 3 to 4 cm) and, most importantly, if the patient performs digitation or splinting maneuvers to evacuate stool from the rectal vault. Digitation may include stabilization of the posterior vaginal wall with the patient s fingers during defecation or, similarly, pressure applied to the perineum or anterior perianal skin, which are hallmarks of the disease. 3,46 The management of a symptomatic rectocele starts with medical treatment, which is composed of a high-fiber diet, fiber supplementation, and an increase in water intake. If patients are not substantially improved with conservative measures, then surgery may be undertaken. Rectocele repair can be performed transvaginally, transanally, or transperineally. The transvaginal approach is the most commonly performed procedure by gynecologists and includes a posterior colporraphy or defect-specific posterior repair, which is often performed in conjunction with other vaginal procedures and anti-incontinence procedures. 46 Conversely, the transanal and transperineal approaches are often performed by colorectal surgeons. Regardless of technique, the aim of surgery is to rebuild the tissue between the rectum and the vagina and to improve obstructed defecation and eliminate digitation of the perineum and vagina. 46 Randomized controlled trials have shown that the transvaginal approach has a lower failure rate than the transanal approach. 47 It should be noted, however, that regardless of the technique implemented, surgical repair carries a high success rate of 70 to 90% for defecation improvement and 60 to 70% improvement in elimination of the need to digitate. 3 enterocele Descent of the small bowel into the lower pelvic cavity associated with a hernia of the peritoneum between the rectum and vagina is termed an enterocele [see Figure 18]. An enterocele may be an asymptomatic radiographic or clinical

12 gastro pelvis floor dysfunction 12 Figure 18 Enterocele. Descent of small bowel into pelvic floor (enterocele) (arrow). Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography All Rights Reserved. finding, or it may be a cause of constipation secondary to obstructed defecation via the small bowel mechanically compressing the rectum. An enterocele results from a defect or absence of the endopelvic fascia at the vaginal apex (a defect between the pubocervical and rectovaginal endopelvic fascia where the peritoneum and vaginal epithelium are opposed without any intervening fascia). 46 Enteroceles have generally been divided into four types depending on their cause and include congenital, traction, pulsion, and iatrogenic. The causes of a congenital enterocele include neurologic disorders (i.e., spina bifida) or connective tissue disorders, traction enteroceles may be caused secondarily by uterovaginal prolapse, and pulsion enteroceles are caused by prolonged high intra-abdominal pressures due to excessive straining at defecation. Certain gynecologic procedures may predispose to the formation of an iatrogenic enterocele, such as colposuspension for stress incontinence or hysterectomy. 48 Enteroceles can be classified based on clinical examination as well as on defecography. Clinically, enterocele classification is based on anatomic location in regard to the vaginal apex, with apical varieties herniating through the apex, posterior enteroceles herniating posterior to the apex, and anterior enteroceles herniating anterior to the vaginal apex. 48 In terms of classifying enteroceles (and sigmoidoceles) based on a defecating proctogram, the position of the lowest bowel loop on maximum patient strain is commonly used. A first-degree enterocele is defined as when the bowel loop sits above the pubococcygeal line, a seconddegree enterocele is where the bowel is below the pubococcygeal line but still above the ischiococcygeal line, and a third-degree enterocele is when the bowel loop is below the ischiococcygeal line. Treatment modalities that exist for enteroceles are mainly surgical, with transvaginal or transabdominal techniques used most often. Enterocele repair is often performed in conjunction with other prolapse procedures. The type of repair and the approach, which is either transvaginal or transabdominal (open or laparoscopic), depends on the preference of the surgeon and whether concurrent pelvic floor or abdominal pathology exists. Traditional transvaginal enterocele repair is performed by making a midline vertical incision over the most prominent portion of the suspected hernia sac and followed by dissection of the anterior rectal wall away from the enterocele after the posterior vaginal wall has been opened. Once the hernia sac has been isolated from the rectum, vagina, and bladder, the sac is opened and two to three circumferential, purse-string sutures of nonabsorbable material are used to obliterate the hernia. Colporraphy and suspension of the vagina are then performed as indicated. 48 Various transabdominal approaches have traditionally focused on obliterating the pouch of Douglas (cul-de-sac) either in an open or a laparoscopic approach. The Moschcowitz procedure encompasses placing three to four concentric purse-string sutures around the cul-de-sac, including the posterior vaginal wall, both pelvic sidewalls, and the serosal layer of the sigmoid colon. Halban described a technique that incorporated longitudinally placed sutures between the uterosacral ligaments through the posterior vaginal wall, the deep peritoneum of the cul-de-sac, and the serosa of the sigmoid colon. Alternatively, transverse plication of the uterosacral ligaments can be performed by placing three to five sutures from one uterosacral ligament to the posterior vagina to the contralateral uterosacral ligament. 48 At our institution, if the defecography supports the symptoms, third-degree enteroceles are performed in conjunction with our urogynecologists. We prefer a sacral colpopexy with either a permanent or biologic mesh. The goal is to close off the pelvic inlet such that the cul-de-sac is not accessible to the small bowel. If a woman wishes to retain her uterus, the mesh is fixed to the back wall of the lower uterus and vagina. It is quite difficult, if not impossible, to determine and analyze the exact role that enterocele repair plays in the correction of a patient s obstructed defecation symptoms because the repair is almost always performed in conjunction with other prolapse procedures. There a few long-term studies evaluating enterocele repair in the literature, but reports suggest a high success rate and a low recurrence rate of approximately 10% in most series. 3 Raz and colleagues reported on their experience with enterocele repair in 49 patients and showed an 82% cure rate. 49 sigmoidocele Obstructed defecation can occasionally be secondary to a colonic cause a sigmoidocele. In this condition, redundant sigmoid colon descends into the pouch of Douglas, herniates between the rectum and vagina during defecation, and subsequently impinges on the rectum during defecation. 50,51 Defecography is the primary mode of diagnosis, which may reveal a sigmoidocele in 4 to 5% of patients. 51,52 In a study by Jorge and colleagues, in 463 patients undergoing defecography for constipation, fecal incontinence, or chronic rectal pain, a sigmoidocele was diagnosed in 5.3% of patients. 51 Physical examination can be unreliable in making the diagnosis. It can be difficult to detect a sigmoidocele; however, when the sigmoid impinges on the pouch of Douglas, it may be felt on digital examination with strain. If the descent is severe, the sigmoid can protrude into the rectal wall and

13 gastro pelvis floor dysfunction 13 sometimes come out the anus. When this happens, if visualized (i.e., on the commode), only the anterior wall of the rectum appears to prolapse. The severity of the sigmoidocele is based on the extent of descent into the pelvis on defecography, as previously described for enteroceles. The surgical procedure for correcting a sigmoidocele is determined by the amount of constipation, degree of prolapse, coexisting incontinence, and amount of sigmoid redundancy. Surgical correction should be reserved for carefully selected patients as the true significance and optimal management of first- and second-degree sigmoidoceles are not fully understood at present. 3 Patients with third-degree sigmoidoceles, however, likely benefit from surgical intervention, namely sigmoid resection or sigmoidopexy in conjunction with posterior compartment repair, which obliterates the cul-de-sac. This has been shown to be effective in relieving symptoms in some patients with obstructed defecation syndrome. 46 Jorge and colleagues reported relief of symptoms in five patients with a third-degree sigmoidocele at a mean follow-up of 23 months. 51 Similarly, Fenner performed either sigmoid resection or sigmoidopexy in three patients and obliteration of the cul-de-sac in four patients, with improvement of symptoms of constipation more pronounced in the sigmoid resection group. 52 When we feel a sigmoidocele is the etiology of defecation dysfunction, we nearly always perform a sigmoid resection with primary anastomosis along with a sacral colpopexy to obliterate the herniated cul-de-sac. nonrelaxation of the puborectalis (anismus, paradoxical contraction of the puborectalis, puborectalis syndrome) In normal individuals, the puborectalis muscle is in a contracted state while at rest and helps maintain the anorectal angle. During normal evacuation, distention of the rectum with fecal material induces the internal sphincter muscle to relax and the external sphincter muscle to contract. At the time of defecation, the external sphincter and the puborectalis muscles relax, and evacuation ensues. In the case of nonrelaxation of the puborectalis, relaxation does not occur, and instead the anorectal angle stays the same or increases when straining to expel stool. Patients are subsequently defecating against an obstructed outlet, which results in excessive straining and inability to expel stool at all. Patients will commonly have a feeling of incomplete evacuation and may need to insert their finger into the anus and manually try to remove stool to complete the evacuation process. 3 This paradoxical contraction of the puborectalis can be elicited on digital examination by feeling the muscle contract while asking the patient to strain (although this may be unreliable). EMG and/or defecography may give more objective evidence of the obstructed defecation. Conservative management of nonrelaxation of the puborectalis should begin with a high-fiber diet, adequate hydration, regular physical exercise, laxatives, and enemas. Puborectalis retraining with biofeedback has been well studied in the literature, with somewhat conflicting results. Biofeedback to treat nonrelaxation reveals efficacy rates between 35 and 80%, and randomized controlled trials have proven biofeedback to be superior to laxatives, sham treatments, or alternative therapies. 56 More recently, injection of botulinum toxin A directly into the puborectalis has been performed, which causes a chemical relaxation and may lead to improvement in symptoms of obstructed defecation. In a randomized controlled study of biofeedback versus botulinum A toxin injection, botulinum proved to be more efficacious in short-term follow-up. 57 At our institution, direct injection of botulinum toxin A into the puborectalis is accomplished with approximately 100 units per side for select patients with paradox. We then follow the botulinum injection with pelvic floor retraining in an effort to improve relaxation for when the botulinum injection wears off in 3 to 6 months. In certain individuals, marked hypertrophy of the puborectalis fibers may occur without known cause. There have been reports of success with daily anal dilation with anal dilators of increasing size to stretch the contracted muscles. 58 Also reported in the literature, but not widely performed, is partial resection of the puborectalis muscle. Wallace and Madden reported excellent results with this technique, 59 whereas Kamm and colleagues reported less success. 60 Most recently, a 90% success rate with this technique has been shown in over 149 patients. 61 rectoanal intussusception (internal prolapse) Full-thickness intussusception of the rectal wall without protrusion beyond the anal canal is termed rectoanal intussusception (internal prolapse) and can be found in 31 to 40% of patients undergoing cinedefecography for obstructed defecation, although the overall true incidence is unknown [see Figure 19]. 62,63 Currently, no uniform consensus on a classification system exists, and the true clinical relevance of rectoanal intussusception remains debated. Figure 19 Defecography revealing rectoanal intussusception (internal prolapse).