Defecography: Technique, Interpretation, and Current Use Arden M

9 Defecography: Technique, Interpretation, and Current Use Arden M. Morris and Susan C. Parker

Defecography, or evacuation proctography, is the on technique, interpretation, and implications dynamic study of expulsion of radiopaque mate- for specific patient populations. rial from the rectum, in order to assess changing anatomic relationships of the pelvic floor and associated organs during evacuation. In 1952, Indications for Testing Wallden 1 first described enteroceles, sigmoidoceles, and rectoceles, using roentgenogram Constipation techniques developed to evaluate patients with symptoms of obstructed defecation. He postu- Defecography was initially developed to assess lated that such outlet obstruction was due to an patients with complaints of constipation and a abnormally deep rectogenital pouch and could sensation of rectal outlet obstruction. The diag- be corrected surgically. However, performing nostic armamentarium has expanded to include these static studies using rectal, vaginal, and anal manometry, electromyography, and colonic small bowel contrast was a cumbersome, expen- transit time studies, all of which are crucial for sive, and embarrassing process for the patient. distinguishing end-organ versus total organ Recognizing the limitations of these studies, etiologies. Therefore, although the major indi- subsequent authors streamlined the procedure cation for performing defecography continues to over the ensuing three decades. be constipation, other complaints may occasion- Broden and Snellman2 proposed the use of ally warrant defecographic evaluation. Table 9.1 cineradiographic methods and a physiologic demonstrates the primary indications and their position, which contributed enormously to the proportionate prevalence among our referred simultaneous study of function and anatomy. patients. There is considerable overlap in many Several centers built radiolucent commodes with of these symptoms and diagnoses. air and water chamber modifications to optimize image density.3 To more closely replicate stool consistency, investigators varied the texture of Suspected Enterocele or Rectocele barium contrast with materials such as oatmeal (Obstructed Defecation) and potato starch. Technological advance- ments in videography and manufacturing have Patients with symptoms of enterocele or recto- enhanced sophistication, efficiency, and patient cele describe prolonged straining at defecation, comfort during the test. with a sensation of partial or complete blockage Today, defecography can provide an invalu- (frequently a “closed trapdoor” preventing able aid in the diagnosis and treatment planning passage of stool).Defecography can demonstrate for patients with constipation and rectal outlet the presence of a rectocele or enterocele, suggest obstruction issues. This chapter explores the the presence of a peritoneocele, and clarify con- current use of defecography, with a special focus tributing disorders such as a nonrelaxing pelvic

85 86 Constipation

Table 9.1. Indication for defecography among patients referred to Pain with Defecation the Minnesota Center for Pelvic Floor Disorders seen over a 12-month period Ill-defined low pelvic pain and painful straining Indication for defecography % (n = 954) at defecation (tenesmus) are frequently difficult Constipation 33 to explain and even more difficult to treat. Suspected enterocele or rectocele (obstructed 11.3 After evaluating for obvious sources, such as defecation) fissure, hemorrhoids, or ulcer, defecography may Incomplete emptying 6.3 Rectal intussusception or prolapse 11.3 help to establish or exclude an anatomic etiology. Fecal incontinence 31.3 For example, paradoxical contraction of pelvic Pain with defecation 3.7 muscles may explain anismus and cramping or Urinary incontinence or uterovaginal prolapse 2.5 spastic pain. Extensive perineal descent may Postoperative evaluation 0.6 result in stretching of the pudendal nerve that can cause a dull, aching sensation after defecation.

ﬂoor, rectal intussusception or prolapse, and Urinary Incontinence and potentially uterovaginal prolapse. Uterovaginal Prolapse

Up to 41% of patients with urogynecologic Incomplete Emptying pelvic floor disorders also have fecal incontinence; therefore, Kelvin et al4 and others have Incomplete emptying refers to a sensation of recommended a complete pelvic floor evaluation stool retained in the rectum after defecation, prior to extensive operative intervention. Alter- coupled with an immediate need to empty again natively, repair of an anterior enterocele or rec- or a need for digital manipulation in order to tocele may uncover previously occult urinary attempt complete evacuation. Incomplete emp- incontinence. Clearly, a careful history and thor- tying is closely related to obstructed defecation ough evaluation are necessary prior to planning and is generally caused by rectal intussuscep- an intervention for patients at risk for both urog- tion, rectocele, or enterocele. ynecologic and anorectal disorders (generally postmenopausal multiparous women). Rectal Intussusception or Prolapse Postoperative Evaluation Internal prolapse or intussusception may be difficult or impossible to diagnose without Follow-up evaluation of postoperative patients is defecography. As intussusception progresses a little-discussed but important indication for toward overt prolapse, patients may complain of defecography. Patients who experience difficult rectal bleeding and a sensation of fullness. Phys- evacuation after an ileal pouch–anal anastomo- ical exam reveals a patulous anus with decreased sis may have a long spout, kinking of the pouch sphincter tone. Anoscopy or rigid proctoscopy or spout, a strictured anastomosis, or another may demonstrate associated conditions, such as mechanical reason for obstruction. Defeco- erythema or a solitary rectal ulcer, thought to be graphy may be helpful for the evaluation of caused by sheer stress on the anterior rectal wall. new-onset evacuation difficulties after a sphinc- teroplasty, prolapse repair, or colon resection. Alternatively, it may help to assess patients with Fecal Incontinence unrelieved symptoms of incontinence after a repair, or to ascertain continence prior to stoma Defecography plays a limited role in evaluation closure. of fecal incontinence, and is most useful among those patients with attendant obstructive symptoms. Defecography can aid in the diagnosis Technique of overflow fecal incontinence, demonstrating retention of stool due to a nonrelaxing puborec- Dynamic defecography, as originally described talis muscle or retained stool within a large by Broden and Snellman2 in 1968, used rectal, rectocele. small bowel, and vaginal contrast. Since that Defecography: Technique, Interpretation, and Current Use 87 initial description, the technique has been prolapse, and potential widening of the recto- further refined, but a consensus still does not vaginal space, which may indicate an enterocele. exist regarding the optimal examination tech- Some authors discourage tampon use, arguing nique.Practitioners may vary the number of cav- that it stents the vagina, thereby obscuring rec- ities or organs that are opacified (small bowel, toceles, enteroceles, and prolapse.7,8 We recom- vagina, bladder, peritoneum), the method of mend opacification of the vagina with 5 to 10cc opacification (ingested or injected contrast, con- of thick barium paste (barium sulfate esophageal trast applied to a sponge or tampon), and even cream, 60% w/w, E-Z-EM, Westbury, NY) the type of contrast used for each anatomic site inserted using a rounded flexi-tip applicator. (liquid, paste, or prepared mixtures). Contrast is slowly injected as the applicator is withdrawn to coat the entire length of the vagina. Contrast The use of bladder contrast is less common and requires sterile bladder catheterization and Options for rectal contrast preparations in- the instillation of 150 to 200cc of water-soluble clude barium suspension, mixtures of barium contrast. Bladder opacification is advocated and starch (oatmeal, potato flakes), and com- for patients with bladder symptoms or a large mercial products formulated specifically for vaginal eversion, and can help to differentiate a defecography. cystocele from an enterocele or rectocele.9 Ikenberry and colleagues5 compared three types of contrast (thin barium liquid, commer- cial paste, and thick prepared contrast paste) in Peritoneal Cavity normal subjects and found that contrast materials and consistency altered their pathologic The small intestine may be highlighted by inges- findings. Increased viscosity resulted in a sig- tion of an oral barium meal given 45 minutes to nificantly increased anorectal angle measure- 1.5 hours before the defecography study, to allow ment. Using thin barium decreased evacuation transit to the distal loops of bowel most likely to time and increased the prevalence of intussu- lie in the pelvis. Although a wide space between ception. The authors found little benefit to the the rectum and vagina filled with air lucency use of elaborate heated mixtures of barium and may indicate an enterocele, the diagnosis is starch but advised against the use of liquid alone made easily if contrast-filled loops of bowel or with other contrasts, particularly when diag- occupy that space. However, a deep pouch of nosing intussusception. Douglas may not fill with small bowel on all Mahieu et al6 also found thin contrast inferior; occasions, resulting in an underinterpretation of among other issues, its rapid passage led to enteroceles. missed pathologic results. Additionally, evacua- Peritoneography allows visualization of the tion of thin barium requires less pelvic floor potential enterocele space by outlining the peri- relaxation than do more viscous substances. toneum with a liquid, water-soluble contrast.10 However, use of thinner contrast would be As originally described by Gullmo,11 60cc of con- appropriate among patients who normally pass trast in inserted via injection into the peritoneal liquid stool, such as some individuals who have cavity in the left lower quadrant or infraumbili- undergone proctocolectomy and ileoanal pouch cally. Other than highlighting the rectovaginal procedure. space, peritoneography reveals the presence (or absence) of in-dwelling organs. Pelvic Structures

Instillation of radiodense contrast into adjacent Filming and Position organs or cavities can provide useful information about abnormal changes in pelvic anatomy Once contrast is inserted, spot films may be during defecation. For example, placement of a taken either with the patient lying in the lateral barium-soaked tampon or gauze sponge, gel, or decubitis position or sitting on a special radiol- thin barium in the vagina allows visualization of ucent commode. The pelvis and opacified vaginal wall motion, possible anterior pelvic rectum are filmed while the patient is instructed 88 Constipation to rest, squeeze, strain, and cough. The films fever, and bleeding during peritoneography. All permit measurement of perineal descent with complications were treated conservatively, with straining, changes in the anorectal angle, and no adverse sequelae.14 changes in anal canal length. Lateral radiographs of the pelvis produce glare in the area of the anal canal, due to the dif- Radiation Dose ference in radiolucency between air and the 12 pelvis. Commodes used for defecography are The radiation dose from fluoroscopy can vary designed to reduce the variation by employing a widely but is generally low. The radiation dose filtration device to absorb radiation below from a barium enema is two to three times that the seat and buttocks. Options include metal of defecography.15 Goei and Kemerink16 esti- strips (usually copper) attached to the side of the mated the mean effective dose at 4.9mSv for commode or water-filled bottles or a doughnut females and 0.6mSv for males; the difference is below the seat. Commodes can be constructed of due to the higher gonadal dose among females horizontally grained pine wood with steps up to compared to males. In contrast to the uterus and a raised seat for ease of filming in a normal ovaries, which are always within the primary sitting position.Alternatively, a commode can be beam, the testes are only exposed to scattered clamped to a horizontal x-ray table beneath a radiation. The authors found a wide range of patient in the lateral decubitis position. With effective doses due to individual variations in vertical movement of the table, the patient ends speed of evacuation. For comparison, the effec- up sitting on the commode. This design allows tive dose due to background radiation is 3 filming of the patient during the movement mSv/year. Assuming that 10mSv carries an from the supine to the sitting position, a distinct increased risk of fatal cancer of 0.04%, the risk advantage among patients with fecal inconti- increase for females is 0.08% and the risk nence or significant genital prolapse, for increase for males is 0.008% above the normal example, who quickly lose contrast in an upright lifetime fatal cancer risk of 20%. position. Of course, the lateral decutibus position is not in any way physiologic as compared to the seated upright position. Moreover, prospective patient evaluation revealed statisti- Measurement Parameters cally significant differences between the two and Interpretation positions relative to anorectal angle, perineal descent, and puborectalis length.13 Because of Normal Defecation these differences, the same technique should be used in each incidence in the same center. Familiarity with the basic steps of evacuation is Whether the left lateral decubitus or upright essential for accurate interpretation of cinede- position is selected, the same position should fecography. As shown in Figure 9.1, the process always be used. begins with migration of stool into the rectum. The increased rectal volume leads to stimulation of pressure receptors located on the puborectalis Risks muscle and in the pelvic floor muscles, which in turn stimulate the rectoanal inhibitory re- Perforation flex (RAIR). The RAIR consists of external anal sphincter contraction and internal anal sphinc- Potential abrasion of the rectum during catheter ter relaxation, allowing sampling of anal canal insertion is a minor risk. Perforation of the contents. When the anal canal is deemed to have rectum during defecography is more a theoreti- solid contents and a decision is made to evacu- cal than a real risk. After 3000 defecographies, ate, the glottis closes, pelvic floor muscles con- our center has yet to experienced such an event, tract, and the diaphragm and abdominal wall and there are no reports of it in the literature. muscles contract—all of which increase abdom- However, perforation of the small bowel during inal pressure. The puborectalis muscle relaxes, peritoneography contrast injection has been resulting in straightening of the anorectal reported. Our center has a 3% rate of complica- angle, and the pelvic floor descends slightly. The tions including small-bowel perforation, pain, external anal sphincter relaxes and anal canal Defecography: Technique, Interpretation, and Current Use 89

Peritoneocele: A caudal extension of the pouch

A. Stool B. Rectoanal inhibitory reflex: of Douglas or rectouterine excavation to 1. Relaxation of internal anal sphincter enters the 2. Contraction of external anal sphincter below the upper third of the vagina. A perito- rectum 3. Sampling of anal canal contents neocele can contain fluid or omentum and is termed an enterocele when it contains bowel. C. Increased intraabdominal pressure: Peritoneoceles can be further described as 1. Closure of glottis and contraction of pelvic floor muscles 2. Contraction of diaphragm and abdominal wall muscles septal, vaginal, and rectal, based on anatomic features.10 Rectal intussusception: A descent of the entire D. Increased anorectal angle: Relaxation of the puborectalis muscle thickness of the rectal wall, which can extend to the anal verge. When the rectal wall intus- E. Anal canal widening: suscepts inferiorly through the anus, the con- Relaxation of puborectalis and external 18 anal sphincter muscles dition is termed rectal prolapse. Rectocele: A rectocele is defined as an out- F. Pelvic floor descent (<2cm) pouching of the rectum that is more pro- nounced during straining and typically occurs G. Evacuation of contents anteriorly, although posterior rectoceles have also been described. More than 2cm of out- H. Closing reflex: pouching may be considered abnormal. 1. Pelvic floor rises 2. Rebound sphincter contraction occurs Rectosacral gap: The horizontal distance between the posterior line of the rectum and the sacrum at S3.17 Figure 9.1. The steps of normal defecation. Rectovaginal space: The distance between contrast in the vaginal and contrast in the 18 contents are evacuated. Upon normal complete rectum. evacuation, the pelvic floor rises and sphincters Sigmoidocele: Abnormal descent of a loop if contract once more in a “closing reflex.” sigmoid into the pelvis which may be first, second, or third degree (Fig. 9.2).19

Measurement Parameters

Appropriate parameters to be measured during defecography have evolved over time, based on the contributions of numerous authors. Accord- ingly, consistent objective measures and their implications are not yet universally accepted due to a lack of uniform technique.3,5,17 However, the following deﬁnitions are generally considered standard based on their widespread use: Anal canal length: The distance from the anal verge (deﬁned by barium marking the skin or a marker placed on the perineum) to the rectum. Anorectal angle: The angle between the axis of the anal canal and the posterior rectal wall (posterior anorectal angle) or the center of the rectum (central anorectal angle). Perineal descent: The vertical movement of the anorectal junction from its position at rest. Reference points are the ischial tuberosities5 or the pubococcygeal line drawn from the Figure 9.2. Measurement of the three degrees of sigmoidocele. (From 6 pubis to the tip of the coccyx. Jorge et al.19) 90 Constipation

Interpretation: “Normal” Table 9.3. Variability in “normal” measurements within and Versus “Abnormal” between studies Measurement Rest Strain The most widely cited early study of “normal” Anorectal angle 60–105 (Goei22)— (degrees) 83–131 (Goei22) 106–134 (Goei22) volunteers was conducted by Mahieu and 23 23 colleagues,3 who retrospectively reviewed 56 70–140 (Ekberg ) 110–180 (Ekberg ) 65–134 (Mahieu3) 105–164 (Mahieu3) defecograms deemed normal from 188 sequen- Perineal descent 2cm tially studied patients. These authors identified Anal canal 22mm men 17mm (Shorvon17) five radiologic signs consistently present in 16mm women 14mm normal patients during defecation including (1) Emptying All or almost all Rectocele None (Mahieu3) increase of the anorectal angle, (2) obliteration <2cm (Shorvon17) of the impression of the puborectalis muscle, (3) Rectosacral gap 10mm (Shorvon17) widening of the anal canal, (4) total or slightly incomplete evacuation of rectal contents, and (5) good resistance of the pelvic floor (Table 9.2). The authors also defined normal as the absence Table 9.3 shows some of the variation seen of pathologic findings. These five criteria have within and between studies attempting to estab- not been validated in any prospective study, nor lish normal measurement parameters. Given the were they formally validated in the cited study difficulty of defining a normal result, how does by a prospective application to retrospective one identify the abnormal? Generally, abnormal data. Nonetheless, numerous subsequent investi- is characterized by subjective symptoms and gators have used the five criteria as objective measurement parameters outside of the broad measures of normal defecography, and thus have “normal” categories. Results deemed abnormal contributed to their construct validity. might include (1) an obtuse or nonchanging Shorvon and associates17 studied 47 sympto- anorectal angle, (2) nonrelaxation or paradoxi- matically normal volunteers who displayed a cal contraction of the puborectalis, (3) incom- broad range of results with respect to anorectal plete evacuation or a need for manual assistance angles and perineal descent. Some of the self- to evacuate, (4) lack of or excessive perineal described normal subjects exhibited surpris- descent, (5) abnormal bowing of the rectal walls ingly pathologic anorectal function, such as fecal (rectal wall teacupping, internal prolapse, frank incontinence. The authors identified mucosal prolapse), or (6) an increasing distance between prolapse or intussusception in 50% of the sub- structures, suggesting a cystocele, sigmoidocele, jects and rectoceles (defined as any bulge outside enterocele, or peritoneocele. the anterior line of the rectum) in 81% of the nulliparous women. However, barium-soaked tampons were inserted into the vagina and thin Reproducibility barium was used to coat the rectal wall prior to placement of a thick paste—both are techniques Variation in the reproducibility of specific defeco- that may alter results.5,20 graphy measurements remains an unresolved issue. To determine interobserver variation, four independent observers, two blinded to the patient’s history, reviewed randomly sequenced videodefecographies performed in constipated Table 9.2. Cinedefecography findings indicating a normal test patients. Two weeks after the initial assessment, result intraobserver variation was determined by a Finding during defecation % normal patients (n = 56) repeat blinded review of unlabeled randomly Anorectal angle increase 100 sequenced studies. The results of interobserver Obliteration of puborectalis muscle 96 accuracy for sigmoidocele, rectal sigmoidocele, impression Anal canal widening 100 intussusception, rectal prolapse, rectal empyting, Total vs. slightly incomplete 55 vs. 45 opening of the anal canal, puborectalis contrac- evacuation tion, and straightening of the anorectal angle and Pelvic floor descent <2cm 84 rectal empyting were 89.5%, 46%, 87.5%, 97.5%, 86.5%, 88.5%, 83%, and 80%, respectively. The Adapted from Mahieu et al.3 intraobserver variations for these same variables Defecography: Technique, Interpretation, and Current Use 91 were 83.8%, 80%, 94.5%, 77%, 84.8%, 80.5%, and abnormalities, which may be addressed during a 85.5%, respectively. In summary, videodefecogra- prolapse repair. phy had an overall accuracy of 82.3%.24 Yang et al25 reviewed the reproducibility of five measurements—posterior and central anorectal angles Rectocele during rest, squeeze and strain, maximal width of the anal canal,maximal width of the rectal lumen, A rectocele is defined as greater than 2cm of and size of the rectocele. The authors reported rectal wall outpouching or bowing while strain- only fair interobserver agreement but high corre- ing, and can precede or accompany rectal intus- lation among most intraobserver measurements, susception, as demonstrated in Figure 9.3. The and these findings have been confirmed by other rectocele can prevent passage of stool both by studies.17,22 Ferrante and colleagues7 noted obstructing the anal orifice and by acting as a significant interobserver variation in anorectal diverticulum to sequester stool. Patients with angle measurements between three interpreters rectoceles commonly complain of the need for but good intraobserver consistency, suggesting frequent sequential episodes of defecation, and that variation in anorectal angle measurements even for manual compression or splinting of the may be due to subjective interpretation of the anterior perineum or posterior vagina in order rectal axis along the curved rectal wall. to completely evacuate. Additionally, with relax- Ultimately, interpretation of defecography ation, patients may experience reduction of the must rely on a constellation of measures, as well rectocele and return of the sequestered stool to as the dynamic functional process. Improved the lower rectum, potentially resulting in incon- standardization of measurement techniques tinence. Rectoceles are found in 25% to 50% of clearly would contribute to more reproducible women, and are often asymptomatic.23,27 results, which would enhance interpretability. Van Dam and associates28 investigated the Additionally, understanding what is normal and utility of defecography in predicting the acceptable to the individual patient is crucial to outcome of rectocele repair. Rectocele size, appropriate interpretation and treatment plan- barium trapping, intussusception, evacuation, ning. In the next section, we discuss specific dis- and perineal descent were measured during orders diagnosed by defecography and their defecography exams of 74 consecutive patients implications for treatment. with symptomatic rectoceles. The patients then underwent a transanal/transvaginal repair, followed by a 6-month-postoperative defecography and reassessment of the five most common Anorectal Disorders: Diagnosis presenting symptoms (excessive straining, and Implications incomplete evacuation, manual assistance required, sense of fullness, bowel movement less Intussusception/Prolapse than three times per week). No postoperative defecograms demonstrated a persistent or recur- Early defecographers recognized rectal intussus- rent rectocele; however, one third of patients had ception (an abnormal telescoping descent of the a poor result based on persistent symptoms. rectum) as an antecedent to frank prolapse (a There was no association between defecography rectal eversion protruding through the anal measurements and outcome of the repair. Still, orifice).1,2,26 Defecography permits the diagnosis the authors concluded that defecography serves of prolapse or near prolapse in patients present- three major purposes in the evaluation of a rec- ing with vague symptoms of bloody or mucus tocele: preoperative evidence of its presence and drainage, painful or ineffective straining at defe- size, documentation of additional pelvic floor cation, or a sensation of obstructed defecation. abnormalities, and an objective assessment of The ability to distinguish between mild to mod- postoperative changes. erate intussusception and near frank prolapse has some value; while satisfactory treatment for intussusception is limited, a number of effective Enterocele/Peritoneocele operations for prolapse have been developed. Defecography provides additional value by clar- A peritoneocele is a caudal invagination of the ifying the presence of concomitant anatomic peritoneum, between the posterior vaginal wall 92 Constipation

Figure 9.3. Rectal intussusception or internal prolapse, increasingly pro- nounced with straining. Note the initial appearance of an anterior rectocele, followed by the “teacup” appearance of the middle image.

and the anterior rectal wall, to a distance of enteroceles have on rectal emptying. Halligan >2cm or inferior to the proximal one third of the and colleagues30 prospectively studied 50 con- vagina (Fig. 9.4). The peritoneocele may inter- secutive patients with constipation, and com- mittently contain small bowel contents, resulting pared their results with 31 controls undergoing in an enterocele (Fig. 9.5). On defecography peritoneography for groin pain. Although a without peritoneography, a peritoneocele is sug- majority of constipated patients (77% versus gested by an unexplained increase in the recto- 10% in the control group) had deep rectogenital vaginal (or rectogenital) space during straining. pouches, only 58% filled with small-bowel con- Similarly, an enterocele is suggested by air-filled tents during the study. Moreover, those patients small-bowel loops within that space. with an enterocele evacuated more rapidly and Increasing use of defecography has led to completely than did the constipated patients more frequent diagnosis of enteroceles; their with or without a deep pouch. prevalence is now estimated at 18% to 37%, and When is the diagnosis of an enterocele rele- upward of 55% of patients with an enterocele vant? Among the 11% of U.S. women who will have other concomitant pelvic floor disorders.29 have a pelvic floor repair by age 80 years,31 pre- However, little is known of the actual impact operative identification and concomitant repair of a peritoneocele or enterocele may help to prevent persistent symptoms or early recurrence of obstruction.22 Nonetheless, among minimally symptomatic or asymptomatic patients, or among those in whom a repair is not otherwise warranted, the prudent surgeon must not over- construe the importance of an incidentally identified enterocele.

Sigmoidocele

The existence and clinical implications of sigmoidocele are controversial. We have demonstrated that a deep rectovaginal pouch may contain small bowel at one time and sigmoid at another time, in the same patient. Jorge et al19 maintain that, as opposed to the small bowel, the herniated sigmoid is more prone to stasis, owing to its larger diameter and more solid contents. Figure 9.4. A peritoneocele extending through the vaginal introitus, 19 seen with combined defecography and peritoneography. V, vagina; R, Jorge et al undertook a study to assess the rectum; P,peritoneocele. incidence and clinical signiﬁcance of sigmoi- Defecography: Technique, Interpretation, and Current Use 93

Figure 9.5. Deep rectovaginal pouch or septal peritoneocele. Upon straining, small bowel enters the pouch, forming an enterocele, and peritoneum extends caudally compressing the anal opening.

doceles as a finding during cindefecography. the sigmoid redundancy, and clinical symptoms. Twenty-four (5.2%) sigmoidoceles were noted The clinical significance of third-degree during 463 cinedefecographic studies.Sigmoido- sigmoidoceles were supported by the fact that all celes were classified based on the degree of eight patients in that group were women with descent of the lowest portion of the sigmoid loop severe evacuatory difficulties,seven of whom had during maximum straining in relation to the fol- impaired rectal emptying on cinedefecography. lowing anatomic landmarks: pubis, coccyx, and All five patients with third-degree sigmoidoceles ischium. First-degree sigmoidocele was consid- who underwent sigmoid resection reported ered when the intrapelvic loop of sigmoid significant symptomatic improvement at a mean was observed on the cinedefecography but follow-up ranging from 14 to 16 months. the sigmoid did not pass caudad to the pubococcygeal line; second-degree sigmoidoceles included sigmoid loops below the pubococcygeal Descending Perineum line but above the ischeococcygeal line; third- degree sigmoidoceles consisting of loops of Like other defecography measures, perineal bowel transcending caudad to the ischiococ- descent is nonspecific and must be interpreted cygeal line.Constipation symptoms were present in context. An abnormal increase in perineal in 20 of the 24 (83%) patients.The most common descent (typically greater than 2cm) has been sensations were incomplete evacuation, strain- described among both incontinent patients and ing, pelvic bloating, rectal pressure or fullness, continent patients who strain during defeca- infrequent bowel movements, and abdominal tion.32–34 These conflicting data underscore the pain. Two thirds of these patients required poorly understood relationship between neuro- assisted defecation including laxatives, enemas, pathic pelvic floor damage and symptomatology. and suppositories.Nine patients had first-degree, Bartolo and associates35 evaluated patients seven had second-degree, and eight had third- with perineal descent using manometric, radio- degree sigmoidoceles. The proposed classifica- graphic, and neurophysiologic studies. When tion system yielded excellent correlation among comparing 32 patients with incontinence and the mean level of the sigmoidocele, the degree of increased perineal descent with 21 patients with 94 Constipation obstructed defecation and increased perineal puborectalis muscle, lack of perineal descent, a descent, the authors found no significant differ- lack of straightening of the rectoanal angle, and ence in the extent of perineal descent or neuro- poor opening of the anal canal.37 Definition of pathic damage to the external anal sphincter. specific measurement criteria (anorectal angle Patients who were incontinent had lower mano- change, perineal descent) would be misleading metric pressures (both resting and squeeze pres- due to the wide range of normal results.38 During sures) while those individuals with obstructed the exam, the patient may strain numerous times defecation had normal manometric pressures. In and evacuate only a small amount of contrast a separate study, these authors also found that with each attempt or fail to empty any contrast at incontinent patients with increased perineal all. Straining against the pelvic floor or a non- descent had severe denervation of both the pub- opening anal canal can accentuate the anterior orectalis and the external sphincter compared bowing of a rectocele or cause posterior rectal to continent patients with increased perineal bowing.Once diagnosed,dyskinetic puborectalis descent, who had partial denervation of the is usually treated with biofeedback and bowel external sphincter only.36 Miller and colleagues34 management. Patients who fail conservative evaluated sensation in two similar patient treatment have been offered botulinum toxin groups. Patients who were frankly incontinent injections into the puborectalis muscle with actually had less perineal descent than continent limited success.39 Several studies have shown that patients with descent, but had severely impaired neither electromyography nor cinedefecography anal sensation. is ideal relative to either specificity or sensitivity Berkelmans et al33 tried to determine if in the diagnosis of paradoxical puborectalis women with increased perineal descent and contraction.15,23,27,40 Therefore, a combination of straining at stool were at risk for future devel- defecography and perhaps surface or intra-anal opment of incontinence. The authors identified sponge electromyography may be the appropri- 46 women with perineal descent who strained ate means of diagnosing of this problem. during defecation but were continent. Twenty- four of the 46 were followed after 5 years, and 13 of these (54%) had developed fecal incontinence, Solitary Rectal Ulcer Syndrome compared with three of 20 (15%) control patients. During their initial evaluation, the Defecography can clarify anatomic changes that patients who previously strained and later devel- contribute to the pathogenesis of solitary rectal oped incontinence had significantly greater per- ulcer syndrome and accordingly may be used to ineal descent at rest and less elevation of the direct therapy. Kuijpers et al41 determined that, pelvic floor during maximal sphincter contrac- among 19 patients with histologic features of tion than the women who strained but did not solitary rectal ulcer syndrome, 12 had intussus- develop incontinence. ception and five patients had inappropriate pub- Thus, perineal descent may be a predictor of orectalis muscle contraction on defecography incontinence among patients with denervation exam. Intussusception can cause stretching of of both the external sphincter and the puborec- the submucosal vessels, ischemia, and ulcera- talis, and in patients with impaired anal sensation. Straining against a nonrelaxing puborec- tion. Among patients with constipation, perineal talis muscle can cause internal prolapse, descent and straining at stool may predict future ischemia and ulceration.26 Patients with solitary fecal incontinence. rectal ulcer syndrome and inappropriate puborectalis muscle contraction may be offered biofeedback, with surgery reserved for Dyskinetic Puborectalis those with significant intussusception.42 Goei and Baeten22 studied pre- and postoperative Dyskinetic puborectalis, paradoxical puborec- defecograms in 11 patients with solitary rectal talis, nonrelaxing puborectalis,and anismus are ulcers who were treated with a rectopexy. In nine terms that describe the absence of normal relax- patients the intussusception and rectal lesions ation of pelvic floor muscles during defecation, were cured, and in two the intussusception and resulting in pelvic outlet obstruction. Defeco- ulcer recurred. This syndrome remains a con- graphic evidence of a dyskinetic puborectalis troversial area, and initial nonoperative treat- includes a persistent posterior indentation of the ment is often offered to all patients. Defecography: Technique, Interpretation, and Current Use 95 Incontinence undergone defecography, Mellgren et al29 noted that only 16% were male. Consequently, under- Defecography may indicate abnormalities of standing of male pelvic floor issues has been pelvic floor function that predispose a patient to limited by a lack of data and attention. Given the incontinence, such as those that occur with two major contributors to female pelvic floor outlet obstruction or prolapse. The anorectal disorders, obstetrical injury and age (which may angle, as a reflection of puborectalis muscle simply be a proxy for decreased collagen), one function, may be more obtuse in incontinent might expect previous pelvic operation and age patients.43,44 Kruyt and associates44 reported on to play contributory roles in male pelvic floor manometry and defecography performed on a issues as well. 48 diverse group of 160 consecutive patients. In this Chen and colleagues studied 40 men with cohort, patients with anorectal angles greater rectoceles among 234 who underwent defecog- than 130 degrees were more likely to leak con- raphy for evacuation disorders.As expected,40% trast during the study and to have frank incon- of the men had previously undergone prostatic tinence than patients with normal anorectal surgery and the mean age was 72 years. However, angles. However, others have found no difference in contrast to females, whose rectoceles are in anorectal angle measurement between incon- nearly always anterior, males presented with tinent patients and normal controls.35,45 48% anterior and 52% posterior rectoceles. Rex and Lappas46 compared manometry and There was no discussion of controlling for age defecography results from 50 consecutive symp- when evaluating the association between previ- tomatic adults. In this study, leakage of contrast ous prostate surgery and rectocele. The authors at rest and failure to reduce the anorectal angle acknowledged that the clinical significance of during the defecography exam were specific but rectoceles and therapeutic strategies for men not sensitive predictors of decreased manomet- remain unknown. ric pressures. However, incomplete evacuation or retention of contrast in rectoceles had excellent correlation with symptoms of outlet obstruc- Pouch Patients tion. The investigators concluded that defecography was most useful for incontinent patients Patients who have previously undergone total with outlet obstruction symptoms. colectomy with ileal pouch–anal anastomosis are Bielefeldt and associates47 agree that defeco- subject to a number of possible long-term com- graphy offers complementary information to plications, including symptoms of impaired manometry. In their study of 43 consecutive pouch evacuation. Defecography can be an patients with fecal incontinence evaluated with invaluable aid to accurate diagnosis and treat- manometry and defecography, a subgroup with ment planning in this setting. Stenosis of the severe fecal incontinence and an incompletely pouch inlet or outlet and kinking of the efferent closed anal canal during defecography also had limb are the most common obstructive disorders. 49 lower resting pressures. Severe anorectal angle Silvis et al described planning of reoperation changes, such as the loss of the puborectalis in five such patients, including developing a tech- muscle indentation into the posterior rectum nique for transabdominal shortening of a long and an overly obtuse anorectal angle, were not efferent limb with a linear stapler. They also reflected in manometric pressures suggesting described correction of an inlet stenosis iden- that the functional integrity of the pelvic floor is tified by defecography and an extensive pouch not reflected in manometric data. revision in one patient with outlet stenosis. Defecography permitted complex, tailored surgery with good short-term relief of symptoms, Specific Patient Populations although no long-term outcomes were available. Male Pediatric Disorders of the pelvic floor are most commonly associated with females, presumably due to Between 3% and 8% of children have significant anatomic and physiologic burdens of childbear- bowel dysfunction.50 Since constipation is ing. In an assessment of 2816 patients who had usually functional in this population, imaging 96 Constipation

Table 9.4. Defecography results in children with constipation Puborectalis Internal sphincter Rectoanal inhibitory Diagnosis relaxation relaxation reflex (RAIR) Rectum Emptying Hirschsprung’s disease Absent Absent Absent Narrow Very poor Neuronal intestinal dysplasia Present Present Absent Massive bowel Nonspecific Intestinal pseudo-obstruction Nonspecific Nonspecific Nonspecific Nonspecific Nonspecific Ultrashort segment Hirschsprung’s Absent Absent Absent Mega Very poor Megarectum* Normal Normal Normal Mega Nonspecific

* Other causes of secondary megarectum and constipation in children include anal fissure, congenital anal anomalies with stricture, anterior anus, and myelomeningocele. All should have a normal internal sphincter relaxation. studies are reserved for patients who do not phy provides objective, reproducible evidence of respond to medical management. Defecography, the evacuatory process, it is vulnerable to the barium enema, and manometry are complemen- subjective interpretation of practitioners. More- tary tests that help to focus a broad differential over, symptomatic and asymptomatic patients diagnosis including Hirschsprung’s disease, may have similar results, while two patients neuronal intestinal dysplasia, intestinal pseudo- with similar symptoms may have very different obstruction, and megarectum. results. These issues likely reflect the multifacto- Defecography is feasible starting at age of 3 or rial etiology of obstructed defecation, which is 4 years. Abnormal findings in the pediatric strongly affected by underlying conditions, as patient include the presence or absence of described above.No single test provides all of the megarectum, paradoxical relaxation, poor relax- information necessary to fully assess consti- ation of the internal sphincter, or descent of the pation or rectal outlet obstruction; however, pelvic floor. Table 9.4 provides a framework for defecography can provide valuable information diagnosis based on defecography and mano- and permit exclusion of conditions not present metry findings. The importance of a thorough (e.g., perineal descent syndrome, intussuscep- workup is underscored when one considers that tion, nonrelaxing puborectalis). unnecessary biopsies can be avoided if imaging Despite controversies regarding relevance and tests are normal. consistency, defecography has been regarded as a useful test since its introduction, and remains one of the best methods for evaluating Multiple Sclerosis the process of defecation. Ongoing efforts at standardization of definitions37 and techniques Among patients with multiple sclerosis, 50% to will help to improve diagnostic reproducibility 70% report constipation or fecal incontinence and allow pre- and postintervention comparison and many complain of both.51 Symptom overlap of patients in order to continue improving care. can make treatment particularly difficult. We start with rectal disimpaction and a whole- bowel cathartic, such as polyethylene glycol, References followed by a bowel regimen of high-fiber diet, laxatives, and enemas. If the constipation 1. Wallden L. Defecation block in cases of deep rectogenital pouch. Acta Chir Scand 1952;103(3):236–238. proves intractable, defecography may reveal 2. Broden B, Snellman B. Procidentia of the rectum outlet obstruction due to a lack of pelvic floor studied with cineradiography.A contribution to the dis- relaxation.52 Such patients may respond to cussion of causative mechanism. Dis Colon Rectum biofeedback, especially those with limited dis- 1968;11(5):330–347. ability and nonprogressive disease.53 3. Mahieu P,Pringot J, Bodart P.Defecography: I. Descrip- tion of a new procedure and results in normal patients. Gastrointest Radiol 1984;9(3):247–251. 4. Kelvin FM, Maglinte DD, Benson JT.Evacuation procto- Conclusion graphy (defecography): an aid to the investigation of pelvic floor disorders. Obstet Gynecol 1994;83(2):307– 314. Defecography is a radiographic examination 5. Ikenberry S, Lappas JC, Hana MP, Rex DK. Defecogra- of anorectal functional anatomy that remains phy in healthy subjects: comparison of three contrast useful despite its limitations. While defecogra- media. Radiology 1996;201(1):233–238. Defecography: Technique, Interpretation, and Current Use 97

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