Abstract
This is a brief presentation of the most common types of anorectal malformations. It was written for the practicing pediatrician. It meant to be a practical guide to identify and manage these pediatric problems from the newborn until adult life. It emphasizes the importance of suspecting the associated defects, as well as to try to avoid the most common errors observed in the management of these malformations. It also includes information that will allow the clinician to establish the functional prognosis for each specific types of defect.
The management of the sequelae is considered an important part of this chapter.
Keywords
Anorectal malformation Imperforate anus CloacaIntroduction
Anorectal malformations are serious congenital defects that present in the form of a wide spectrum, which can be treated with relatively easy surgical procedures and have good functional prognosis for bowel and urinary control. On the other extreme of the spectrum are complex anorectal and urogenital malformations that require sophisticated, technically demanding surgical procedures to be repaired and have rather poor functional prognosis for bowel, urinary, and sexual function.
It is rather regrettable that a patient born with a “good prognosis” type of defect ends up suffering from fecal and (or) urinary incontinence due to a deficient surgical care. That is the reason why in this chapter, emphasis is placed in the management of the “benign” group of anorectal malformations, which happens to include the greatest number of cases.
Incidence
Anorectal malformations occur approximately in 1 of 5000 live births (Brenner 1975). Its cause remains unknown and it seems to be multifactorial (Wang et al. 2015). Some types of anorectal malformation such as recto-perineal fistula and rectovestibular fistula occur more frequently in families (Falcone et al. 2007). In patients with Down syndrome, the most common defect found is imperforate anus without fistula, an anomaly that is uncommon in patients without Down syndrome (Torres et al. 1998).
The most common defect in females is rectovestibular fistula, whereas the most common defect in males is rectourethral fistula. Cloacal malformations are more common than formerly thought, most likely because they were previously misdiagnosed as rectovaginal fistulas (Rosen et al. 2002).
Classification
Classification of anorectal malformations
Males | Females |
|---|---|
Perineal fistula | Perineal fistula |
Rectourethral fistula | Vestibular fistula |
Bulbar | Persistent cloaca |
Prostatic | ≤3 cm common channel |
Recto-bladder neck fistula | >3 cm common channel |
Imperforate anus without fistula | Imperforate anus without fistula |
Rectal atresia | Rectal atresia |
Complex defects | Complex defects |
Associated Malformations
Most babies (50–60%) with imperforate anus have one or more abnormalities that affect other systems (Smith and Saeki 1988; Cho et al. 2001).
Cardiovascular Anomalies
Cardiovascular anomalies are present in approximately a third of patients with imperforate anus, but only 10% require treatment in the author’s series. The most common lesions are atrial septal defect and patent ductus arteriosus, followed by ventricular septal defect and tetralogy of Fallot. The literature (Greenwood et al. 1975; Teixeira et al. 1983) mentions an incidence of 12–22%, but about one third of the cases were hemodynamically unstable.
Gastrointestinal Anomalies
Malformations of the gastrointestinal tract have been described occurring in 15–18% of cases of ARM (8–9). Esophageal atresia has been reported in 7–15% of cases of ARM (Casaccia et al. 2009; Shin et al. 2013; Hassink et al. 1996) and duodenal atresia in 3–4% (Casaccia et al. 2009; Hassink et al. 1996). Hirschsprung’s disease has been found in three patients in the author’s series of 2100 cases, and overdiagnosis of this association is probably due to the high incidence of constipation seen in patients with anorectal malformations.
Sacral Anomalies
Anterior-posterior (a) and lateral (b) sacral ratios
Spinal Cord Anomalies
Approximately 25% of patients with ARM suffer from tethered cord (Levitt et al. 1997a). The presence of the defect seems to have more influence on the urinary function and the motor activity of the lower extremities. The diagnosis of tethered cord can be done with a lumbosacral ultrasound during the first 3 months of life. After that, the diagnosis can only be made with an MRI of the spine (van den Hondel et al. 2016).
Vertebral
Hemivertebrae are commonly seen. The implication of these on bowel and urinary control has not been determined. However, they have important orthopedic implications (scoliosis).
Genitourinary Anomalies
Improved imaging has shown an increasing range of upper and lower urinary tract anomalies (Rich et al. 1988). The incidence increases with increasing complexity of the anorectal defect. Vesicoureteral reflux is the most common functional anomaly found, and renal agenesis and dysplasia is the most frequent malformation.
Gynecologic Anomalies
Gynecologic anomalies are a significant concern in patients with anorectal malformations (Levitt et al. 1998). In the newborn period, hydrocolpos can lead to urinary obstruction or can cause pyocolpos, in patients with cloacas (Bischoff et al. 2010).
Müllerian anomalies may manifest later when teenagers have obstruction of menstrual flow. Large intra-abdominal collections and peritonitis can develop, or patients may have amenorrhea because of the absence of the Müllerian structures. Obstruction to menstrual flow can occur as an atresia at any level, such as the tube, the cervix, or a hemivagina. Uterine septation abnormalities (predominantly bicornuate uterus) vaginal septum and associated vaginal atresia can also occur. During the definitive repair or at the time of colostomy closure, the intra-abdominal gynecologic structures must be inspected and its patency tested. The full obstetric impact of these anomalies is not yet known.
Anorectal Anatomy and Pathophysiology
Bowel control is the result of a complex interplay among sphincter function, anorectal sensation, and colonic motility. All these factors are affected in children with anorectal malformations.
Sphincter Mechanism
The sphincter mechanism is represented by a funnel-like structure. The exposure afforded by the posterior sagittal approach shows that the levator musculature continues down to the anal dimple with vertical striated muscle fibers called the “muscle complex.” Electrical stimulation of the upper end of the levator group pushes the rectum forward. Stimulation of the muscle complex (vertical fibers) elevates the anus, and stimulation of the parasagittal fibers closes the anus (Peña 1989). Children with anorectal malformations have varying degrees of striated sphincter muscle development from almost normal to virtually no muscle at all.
Sensation and Proprioception
Under normal circumstances, the anal canal is an exquisitely sensitive area (Duthie and Gairns 1960). It allows the individual to discriminate solids, liquids, and gas. The overwhelming majorities of children with anorectal malformations are born without an anal canal and therefore lack this kind of sensation. There is, however, proprioception, which is described as a vague feeling that is perceived when the rectum is distended, simultaneous with stretching of the voluntary muscle that surrounds the rectum (Skerritt et al. 2016). The clinical implications are that these patients lose control when they suffer an episode of diarrhea, but may have the ability to be toilet trained when they can form solid stool and can learn to perceive it.
Colonic and Rectosigmoid Motility
The intestinal contents reach the cecum in a liquid state. It then takes about 20–24 h for that liquid fecal material to reach the rectum and become formed stool as a consequence of the absorption of water that occurs in the colon. The rectosigmoid acts as a reservoir and holds the fecal material for a variable period of time usually about 24 h. The anal canal (below the pectinate line) is usually empty because of the action of the surrounding sphincteric mechanism. Peristaltic waves in the colon push the fecal material toward the anus and touch the exquisitely sensitive tissue of the anal canal, thereby providing valuable information related to the nature of the rectal contents (solid, liquid, or gas). Depending on the surrounding social circumstances, the individual may contract the sphincteric mechanism to avoid a bowel movement and then voluntarily relax at the appropriate time. Normal defecation allows massive emptying of the rectosigmoid, followed by another resting period of about 24 h, during which the rectosigmoid again acts as a reservoir.
Children with anorectal malformations suffer from rectosigmoid hypomotility of different severity. This results into constipation of different degrees, which is self-perpetuating and self-aggravating to the point that if left untreated, megasigmoid develops. In extreme cases, fecal impaction and encopresis, or overflow pseudoincontinence, may develop. It seems that constipation is worse with lower defects. Constipation should not be underestimated and must be treated aggressively.
Children with anorectal malformations, who have lost their rectosigmoid, suffer from the opposite problem (i.e., tendency to have diarrhea). These children have no reservoir capacity, are highly sensitive to certain foods, and suffer from incontinence.
Clinical Findings and Initial Management
Algorithm for the treatment of a male newborn with an anorectal malformation
Algorithm for the treatment of a female newborn with an anorectal malformation
External appearance of the perineum of male patients with anorectal malformations. (a) Perineal fistula with “bucket handle”, prone position. (b) Rectourethral bulbar fistula, prone position. (c) Flat bottom, patient in supine position
External appearance of the perineum of female patients with anorectal malformations (a) Perineal fistula. (b) Vestibular fistula. (c) Cloaca
Radiologic evaluations do not show the real anatomy before 24 h because the rectum is collapsed by the muscle tone of the sphincters that surround its lower part. Therefore, radiologic evaluations done too early (before 24 h) will likely reveal a “very high rectum” and therefore yield a false diagnosis.
During the first 24 h, the newborn should receive intravenous fluids, antibiotics, and nasogastric decompression to prevent aspiration. The clinician should use these hours to evaluate for the presence of associated defects such as cardiac malformations, esophageal atresia, and urologic problems. An echocardiogram can be performed, and the baby should be checked for the presence of esophageal atresia. A plain radiograph of the lumbar spine and sacrum should be taken to evaluate for hemivertebrae and sacral anomalies. A spinal ultrasound helps screen for tethered cord. Ultrasonography of the abdomen evaluates for the presence of hydronephrosis, and pelvic ultrasonography in females with cloaca evaluates for the presence of hydrocolpos. During opening of the colostomy, it is mandatory that the hydrocolpos be drained when present. If the hydrocolpos is not large enough to reach the abdominal wall above the bladder, to be sutured to the skin, it can be drained with a pigtail tube.
If the baby has signs of a perineal or vestibular fistula, a posterior sagittal repair can be performed without a protective colostomy in the newborn period, provided the surgeon has experience with that kind of procedure. If the baby is ill from associated problems, or premature, or if the clinician chooses to wait until the baby is a little older, the fistula can be gently dilated. The repair in such cases should not be delayed more than several months.
Cross-table lateral X-ray, reachable rectum
Cross-table lateral X-ray, high rectum
Performing the definitive repair not later than at 2–3 months of age has important advantages for the patient, including less time with an abdominal stoma, less size discrepancy between the proximal and distal bowel at the time of colostomy closure, easier anal dilation, and no recognizable psychological sequelae from painful perineal maneuvers.
The potential advantages of an early operation must be weighed against the possible disadvantages of an inexperienced surgeon unfamiliar with the minute anatomic structures of an infant’s pelvis.
A trend to repair these defects without a protective colostomy (Albanese et al. 1999) must be balanced against the concern that such a repair without a colostomy is done without precise anatomic information about the patient’s specific type of anorectal defect. The most catastrophic complications occurred in patients operated on without a colostomy and, as a consequence, without a distal colostogram. While looking for the rectum, the surgeon might inadvertently find and injure the urethra, an ectopic ureter, the bladder neck, the vas deferens, or the seminal vesicles (Hong et al. 2002).
With emerging advancements in perinatology and prenatal ultrasound techniques, anorectal malformations are more commonly being suspected (Bianchi et al. 2013). Prenatal sonographic findings, such as a dilated rectum, hydrocolpos, or demonstration of an associated urological and spinal anomaly, can make the primatologist suspicious that the fetus may in fact have an anorectal malformation.
Limited Posterior Sagittal Anorectoplasty
When a perineal fistula is diagnosed (Fig. 5), the anal orifice is always located anterior to the sphincter mechanism. A limited posterior sagittal anoplasty can be performed in the newborn period. It is advantageous to perform this operation in the first 48 h of life because the meconium is sterile. When such an operation is delayed and performed at several months of life, a complete bowel preparation, including a postoperative period of parenteral nutrition without oral intake, is recommended to reduce the risk of perineal infection.
The baby is placed prone. In males, a urinary catheter is inserted. The distal end of the rectum is intimately attached to the posterior urethra, and urethral injury must be avoided. In females, the clinician must acknowledge an intimal contact of the rectum with the vagina, in cases of perineal fistula, and a thin common wall between rectum and vagina in cases of vestibular fistula. Multiple 6-0 silk sutures are placed at the mucocutaneous junction around the fistula orifice. The posterior sagittal incision divides the posterior sphincter in half and is continued circumferentially around the fistula. While traction is maintained on the bowel, a circumferential dissection is performed to mobilize and reposition the bowel within the limits of the sphincter. The bowel wall is sutured to the skin with fine, absorbable sutures under slight tension. The perineal body is reconstructed.
Colostomy
Descending colostomy
(See chapter on “Stomas of the Small and Large Bowel”.)
Management After Colostomy (High-Pressure Distal Colostogram)
Distal colostogram showing a rectourethral bulbar fistula
Distal colostogram showing a recto-bladder neck fistula
Anorectal Reconstruction
Basic Principles
All defects can be repaired using a posterior sagittal approach. Approximately 10% of male patients (those with a rectum–bladder neck fistula) and about 40% of female patients with a cloaca may in addition require an abdominal approach for mobilization of a high rectum or vagina. A Foley catheter is inserted into the bladder. The catheter sometimes goes into the rectum through the fistula rather than into the bladder. To avoid this, the surgeon can direct the catheter with a lacrimal probe inserted in the tip of the Foley catheter to function as a guide. Alternatively, a “Coudee” catheter can be used. Occasionally, the catheter must be positioned intraoperatively once the fistula is exposed. The patient is placed in prone position with the pelvis elevated.
Patient in prone position with proper padding
Posterior Sagittal Anorectoplasty for Anomalies in Males
Rectourethral Fistula (Bulbar and Prostatic)
Essential steps for posterior sagittal anorectoplasty in male patients. (a) Planned posterior sagittal incision. (b) Posterior sagittal approach with the parasagittal fibers and ischiorectal fat split in the midline. (c) Posterior rectal wall exposed. (d) Posterior rectal wall opened in the midline. (e) Posterior rectal wall opened going anteriorly until the rectourethral fistula is identified. (f) Separation of the rectum from the posterior urethra with dissection above the fistula. (g) The rectum fully mobilized and in this case tapered. Sutures are placed anteriorly to close the perineal body. (h) The rectum pulled through and placed within the limits of the sphincter mechanism. (i) Closure of the levator and tacking of the posterior edge of muscle complex to the posterior rectal wall. (j) Closure of the posterior sagittal incision and completed anoplasty
In boys with a rectourethral bulbar fistula, upon opening the levator muscle, the bowel is very evident. In boys with a rectoprostatic fistula, the rectum is much smaller and located much higher in the incision just under the coccyx. The distal colostogram provides information that is valuable at this point for determining where the rectum can be found (Fig. 9). In the case of a recto-bladder neck fistula, the rectum is not visible through a posterior sagittal approach and should not be searched for (Fig. 10).
Operative view, posterior sagittal approach. The rectourethral fistula is seen with a metallic probe in it
Operative view. Fine silk sutures are placed through the mucosa of the cephalad hemicircumference of the fistula
Once the rectum is fully separated from the urinary tract, a circumferential perirectal dissection is performed to gain enough rectal length to reach the perineum. To achieve this, the fascia that surrounds the rectum must be divided, including blood vessels and nerves attached to the rectum. This is a key plane to identify. While the surgeon is applying traction to the rectum, the dissection continues in a circumferential manner. The vessels that hold the rectum are coagulated and divided until enough rectal length has been achieved. The rectum has an excellent intramural blood supply; even in cases of a very high prostatic fistula, sufficient length can be obtained without making the rectum ischemic. When the rectal wall is injured, however, this blood supply is damaged and ischemia may occur. Therefore, every effort must be made to perform this dissection as close as possible to the rectal wall but without damaging the bowel wall. Once enough length has been achieved to perform a tension-free bowel-to-skin anastomosis, the size of the rectum must be evaluated and compared with the available space. If necessary, the rectum can be tapered by removing part of its posterior wall and reconstructed by closing with two layers of long-term absorbable interrupted sutures. The urethral fistula is closed with interrupted absorbable sutures.
Levator muscle sutured behind the rectum
Sutures on the posterior edge of the muscle complex which anchor the rectum
Anoplasty
Recto-bladder Neck Fistula
In patients with a recto-bladder neck fistula, an abdominal approach via either laparoscopy or laparotomy, in addition to the posterior sagittal approach, is necessary to mobilize the rectum.
Operative view of a recto-bladder neck fistula showing the rectosigmoid ending at the bladder neck. (a) Laparoscopic view. (b) View via laparotomy
Ligation of the peripheral branches of the inferior mesenteric vessels with preservation of the main trunks, in order to gain length on a very high rectum
With the legs lifted up, a midsagittal incision is made and the presacral space dissected. Then the rectum is pulled through. An anoplasty should be performed as previously described. Tacking of the rectum to the muscle complex is important because these patients have poor pelvic musculature and are particularly prone to prolapse.
Imperforate Anus Without a Fistula
Anorectal malfromations (ARMs) without fistula occur in approximately 5% of all cases of ARMs. Bischoff et al. (Bischoff et al. 2014) in a series of 2186 cases of ARMs found 92 (4.2%) patients had no fistula. Thirty-seven (40%) patients had trisomy 21. In patients with an imperforate anus and no fistula, the blind end of the rectum is located at the same level as in a patient with a bulbar urethral fistula. Even when patients do not have a fistula, the rectum is still intimately attached to the posterior urethra in males or vagina in females, requiring careful dissection. The rest of the repair is performed as described for rectourethral fistulas.
Rectal Atresia and Stenosis (Hamrick et al. 2012)
Repair of rectal atresia and stenosis involves connecting the blind dilated end of the rectum proximally with the anal canal distally. Both structures are usually separated by a few millimeters of fibrous tissue. The rectum must be sufficiently mobilized to allow the performance of an end-to-end anastomosis to the anal canal. The wound is then closed by reconstructing all the muscle structures, as previously described. Since the anal canal is normal, these patients have excellent potential for bowel control. This defect in particular is frequently associated with a presacral mass, often a teratoma, which must be screened for.
Posterior Sagittal Anorectoplasty for Anomalies in Females
Vestibular Fistula
The complexity of this defect is frequently underestimated. Patients with a vestibular fistula are born with excellent potential for bowel control. Thus, every effort should be made to give these patients the best opportunity to undergo a successful reconstruction with a single operation. A protective colostomy minimizes the chances of these complications.
With the patient in prone position, a midline incision is performed. The midline incision continues around the fistula into the vestibule, and multiple 5-0 sutures are placed circumferentially at the fistula site. While traction is placed on these sutures, the rectum is dissected in a circumferential manner. The posterior rectal wall can easily be identified, and the dissection must start from the posterior aspect and be extended laterally. The last step, separation of the rectum from the vagina, is the most delicate part of the dissection. The common wall between the rectum and vagina in this kind of defect is long and extremely thin. Once fully separated, the rectum must be mobilized as previously described, to gain enough length to perform a tension-free bowel-to-skin anastomosis. The limits of the sphincteric mechanism are electrically determined and marked with temporary silk sutures. The perineal body is then reconstructed by bringing together the anterior limit of the sphincter complex. The posterior edges of the muscle complex are reapproximated taking bites of rectal wall, as described previously for males. The anoplasty and wound closure are performed as described for males. For the extremely unusual case of a rectovaginal fistula, the technique is the same except that the rectum requires more mobilization to reach the perineum.
Cloaca
Cloaca represents a spectrum of defects that goes from “benign” cloaca with a good functional prognosis that can be repaired with a relatively simple surgical technique, to very complex malformations with many anatomic variations that require different surgical maneuvers to be able to successfully reconstruct those patients (Bischoff 2015).
The group of patients born with a “benign” type of cloaca will have bowel and urinary control, will become sexually active, and may get pregnant and deliver by cesarean section. All this is possible, provided the malformation is repaired with a meticulous and delicate technique. Fortunately, this represents more than 50% of all cloacas. On the other hand, complex cloaca with a common channel longer than 3 cm should be repaired by surgeons fully dedicated to repair these malformations. The length of the common channel is better determined during cystoscopy.
Cloacas with a Common Channel Shorter than 1 cm
These patients are treated almost like those that are born with a recto-vestibular fistula (Bischoff 2016). They do not require total urogenital mobilization as the urethra is perfectly visible in its natural location, even when it is a little hypospadic. The first step consists of approaching the patient through a posterior sagittal incision, identifying the posterior wall of the rectum, clearing the posterior and lateral walls of the rectum, and then performing a very meticulous dissection to separate the anterior rectal wall from the posterior vaginal wall. Once the separation is completed and the rectum reaches the center of the sphincter mechanism without tension, the posterior and lateral walls of the vagina are mobilized in order to create an adequate introitus. The limits of the sphincter are delineated with the use of an electrostimulator and the perineal body is created. An anoplasty is performed.
Cloacas with a Common Channel Length Between 1 and 3 cm
(a) Posterior sagittal view of a typical cloaca with a common channel of 2 cm with a visible vaginal septum. (b) A cloaca with a very large vagina (hydrocolpos). The rectum opens higher in the vagina and is not seen here
(a) Total urogenital mobilization (cloaca with a short common channel, <3 cm). (b) The intrinsic anatomy of the cloaca is exposed posterior sagittally. (c) The rectum is separated from the urogenital sinus. (d) Sutures are placed around the urogenital complex for uniform traction to facilitate mobilization of the urogenital sinus. (e) Urogenital sinus fully mobilized. (f) Finished repair
Cloacas with a Common Channel Longer than 3 cm
3D cloacagram
The repair of these complex defects usually starts with a posterior sagittal approach, separation of the rectum as previously described, and a total urogenital mobilization. Occasionally the surgeon may find that it is possible to bring the urethra and the vagina in cases with a common channel of 4 or 4.5 cm.
In the event that the total urogenital mobilization was not enough to perform an adequate urethral and vaginal repair, the next step should be a laparotomy to divide all the avascular attachments of the vagina and urethra. If that is not enough, it will be necessary to separate the bladder and urethra from the vagina(s). This is performed through the abdomen, with the bladder open, and catheters placed through the ureters. This separation represents the most technically demanding and sophisticated maneuver in the repair of cloacas; it requires experience and delicate technique.
(a) Very large hemivaginas with a vaginal septum and long common channel. (b) Vaginal switch maneuver
Extremely long common channel – hemivaginas and rectum connected to the bladder neck
A and B, vaginal replacement with the rectum
Vaginal replacement with the sigmoid colon
Vaginal replacement with small bowel (a) and (b). Using the portion of ileum with the longest mesentery. (c) Pulling the small bowel down as a neovagina (the insert shows an anastomosis to the upper part of the vagina)
Once in the abdomen, either during the main repair or at the time of colostomy closure, the patency of the Müllerian structures is investigated by passing a No. 3 feeding tube through the fimbriae of the fallopian tubes, injecting saline, and observing the saline solution to come out through the vagina. If one of the systems is not patent, the atretic Müllerian structure should be excised, with great care to avoid damage to the blood supply of the ipsilateral ovary. When both Müllerian structures are atretic, they should be left in place. The patient must be monitored closely and further investigated with ultrasound when she reaches puberty.
After the repair of a cloaca, in cases with a common channel shorter than 3 cm, a Foley catheter is left in place for a period of 2–3 weeks. In cases of longer common channels, a suprapubic tube is left if the surgeons feel that the patient will require such diversion for less than 3 months. In complex reconstructions, a vesicostomy is recommended, particularly in cases with vesicoureteral reflux and (or) hydronephrosis. Later on, the bladder function should be evaluated to determine the possible urologic strategy to follow.
At the time of colostomy closure, endoscopy should be performed to be sure that the repair is intact, that there is no prolapse, stricture, or urethrovaginal fistula. If the cloaca repair did not require a laparotomy, the time of colostomy closure is the opportunity to investigate the patency of the Müllerian structures.
General Principles of Postoperative Care
In the absence of a laparotomy, oral feedings may begin when the child is awake. Antibiotics are given for 48 h. In males who had a rectourethral fistula, the urinary catheter should be left in place for 7 days.
Anal dilatation program
Patient age | Hegar dilator |
|---|---|
1–4 months | Size no. 12 |
4–8 months | Size no. 13 |
8–12 months | Size no. 14 |
1–3 years | Size no. 15 |
3–12 years | Size no. 16 |
>12 years | Size no. 17 |
Dilatations must continue after colostomy closure. Once the dilator can be inserted easily, the frequency of dilations is reduced to once a day for 1 month, twice a week for 1 month, once a week for 1 month, and then once a week for 3 months.
After the colostomy is closed, the patient may have multiple bowel movements and perineal excoriation may develop. A constipating diet may be helpful in the treatment of this problem. After several weeks the number of bowel movements decreases, and most patients will suffer from constipation. This constipation must be watched for and proactively treated to avoid the formation of megasigmoid and overflow pseudoincontinence (Peña and el Behery 1993). After 3–6 months, a more regular bowel movement pattern develops. A patient who has 1–3 bowel movements per day remains clean between bowel movements, shows evidence of “feeling” during the bowel movement and pushes, and generally has a good prognosis. This type of patient is trainable. A patient with multiple bowel movements or one who passes stool constantly without showing any signs of sensation or pushing typically has a poor functional prognosis for bowel control. The original type of malformation, as well as the quality of the sacrum and spine, predicts the potential for voluntary bowel movements.
Outcomes
Complications
All the usual postoperative complications may occur after these operations. In addition, some specific problems develop both early and late in the postoperative course.
Wound infection and retraction are known to occur. When the infection affects only the superficial layers of the wound, is not accompanied by dehiscence of the structures pulled through, and is promptly treated, it is likely that no functional sequelae will result. On the other hand, infection accompanied by dehiscence may reach catastrophic proportions and leave sequelae that include incontinence, strictures, acquired atresias, recurrent fistulas, and severe pelvic fibrosis.
Infections and dehiscence have occurred mainly in patients operated on primarily, without a colostomy. Therefore, although there is the benefit to operate earlier, primarily, and without a colostomy, it must be remembered that a colostomy is a very valuable adjunct in the management of these defects. Every surgeon must make a decision regarding this issue based on his personal experience.
It is very difficult to determine the precise causes of these complications; however, it seems the main contributing factors are fecal contamination, ischemia, and suture line tension, (often from the incomplete mobilization of structures).
Rectal or vaginal strictures (or both) are usually due to ischemia and (or) tension.
An anal dilatation program is recommended to avoid strictures; however, these maneuvers prevent only minor, ringlike strictures. Difficult anal dilatations usually reflect a major problem related to ischemia or tension that will result in a long narrow stricture or even acquired atresia.
Rectal mucosal prolapse may occur in less than 5% of cases; to prevent this from happening, several maneuvers are recommended, including: (A) tacking of the posterior rectal wall to the posterior edge of the muscle complex, (B) tapering a dilated rectum if necessary, and (C) performing the anoplasty under slight tension so that after the sutures of the anoplasty are cut, the rectum retracts slightly with no mucosa being visible.
Prolapse is managed by full-thickness trimming and is performed when prolapse causes excess mucus production and bleeding or interferes with the patient(s) quality of life.
A review revealed significant urologic injuries in male patients who underwent repair of anorectal malformations (Hong et al. 2002). The posterior sagittal approach, when performed without a good preoperative distal colostogram, was the most important source of these complications. Urethral, ureteral, vas deferens, and seminal vesicle injuries can occur. The laparoscopic approach when done for malformations in which the rectum ends at the bulbar urethra risks leaving behind a posterior urethral diverticulum (the original distal rectum). Postoperative neurogenic bladder in male patients who undergo a technically correct operation for the treatment of anorectal malformations must be extremely unusual.
Constipation is the most common sequel after surgical repair of anorectal malformations. The lower the malformation, the more likely the development of constipation. A vicious cycle ensues with megarectosigmoid leading to more constipation. Constipation that is not properly managed will lead to more megarectosigmoid, resulting in overflow pseudoincontinence. Patients appear to be incontinent, but if their constipation is managed appropriately, they become continent. Such patients sometimes benefit from sigmoid resection to reduce their laxative requirement (Peña and el Behery 1993).
Every effort must be made to avoid this cycle and maintain a collapsed and clean bowel from the moment the baby is born. Transverse colostomies left for a long period of time lead to severe megarectosigmoid. Loop colostomies may also contribute to distal fecal impaction, dilation, and subsequent constipation. An adequate treatment of constipation starting after colostomy closure is very important.
Continence
Bowel control is achieved in about 75% of patients.
Voluntary bowel movement (VBM) and type of defect
Defect | Cases | Patients with VBMs | |
|---|---|---|---|
n | % | ||
Atresia or stenosis | 11 | 11 | 100 |
Perineal fistula | 58 | 56 | 97 |
Vestibular fistula | 146 | 131 | 90 |
Imperforate anus without fistula | 40 | 31 | 78 |
Bulbar fistula | 112 | 89 | 79 |
Cloaca common channel ≤3 cm | 99 | 65 | 66 |
Prostatic fistula | 109 | 71 | 65 |
Vaginal fistula | 5 | 3 | 60 |
Cloaca common channel >3 cm | 69 | 24 | 35 |
Bladder neck fistula | 49 | 10 | 20 |
Total | 698 | 491 | 70 |
Soiling and type of defect
Defect | Patients with soiling | ||
|---|---|---|---|
Cases | n | % | |
Perineal fistula | 57 | 9 | 16 |
Vestibular fistula | 135 | 49 | 36 |
Atresia or stenosis | 10 | 4 | 40 |
Bulbar fistula | 105 | 51 | 49 |
Imperforate anus without fistula | 39 | 20 | 51 |
Cloaca common channel ≤3 cm | 91 | 57 | 63 |
Prostatic fistula | 110 | 86 | 78 |
Vaginal fistula | 5 | 4 | 80 |
Cloaca common channel >3 cm | 55 | 46 | 84 |
Bladder neck fistula | 48 | 43 | 90 |
Total | 655 | 369 | 56 |
Totally continenta patients and type of defect
Defect | Cases | Totally continent | |
|---|---|---|---|
N | % | ||
Perineal fistula | 52 | 43 | 83 |
Atresia or stenosis | 9 | 5 | 56 |
Vestibular fistula | 135 | 86 | 64 |
Imperforate anus without fistula | 36 | 18 | 50 |
Bulbar fistula | 101 | 46 | 46 |
Cloaca common channel ≤3 cm | 91 | 32 | 35 |
Vaginal fistula | 5 | 1 | 20 |
Prostatic fistula | 105 | 19 | 18 |
Cloaca common channel >3 cm | 52 | 6 | 12 |
Bladder neck fistula | 46 | 3 | 7 |
Total | 632 | 259 | 41 |
All patients with anorectal malformations, regardless of the complexity of the defect, can be kept completely dry of urine and clean of stool after the age of 3, either because they achieve bowel and urinary control or because a bowel management program is implemented to keep them artificially dry and clean, with the use of enemas. This program is used in the 25% group of patients that suffer from fecal incontinence (Bischoff and Tovilla In press; Bischoff et al. 2009; Peña 1990). With the rational administration of enemas and, sometimes, diet and drugs, most patients remain clean for 24 h after the administration of the enema. Only patients with non-manageable loose stool secondary to an absent or a short colon need a permanent colostomy.
Patients suffering from fecal incontinence are evaluated and classified into those with constipation or those with increased motility (tendency to have diarrhea). In the first group, the saline enema must be of large volume, with additives (such as glycerin, soap, and/or phosphate) to help empty the colon. This program takes advantage of the decreased bowel motility in constipated patients; they remain clean for the next 24 h. No laxatives or diets are given in these types of patients. The second group (patients who suffer from increased bowel motility because of loss of the rectosigmoid), require a constipating diet, medication to decrease bowel motility, and a smaller daily saline enema (Bischoff and Tovilla In press; Bischoff et al. 2009; Peña 1990).
The treatment is adjusted by trial and error over a period of 1 week with radiologic monitoring. Approximately 95% of patients become clean. Bowel management is started just before the patient has to go to school and join their classmates who are already wearing regular underwear. Most patients and parents are very happy with the implementation of this program.
Diagram showing appendicostomy
Neoappendix made from a tabularized flap of colon
Some patients benefit from an enema program early on, but if they have potential for bowel control, when they are a little older, a laxative trial can be employed to help their colon empty, with careful radiologic monitoring. This may allow them to demonstrate the capacity for voluntary bowel movement and thus eliminate the need for enemas.
Certain patients in whom the rectum was mislocated during the original operation may be candidates for a reoperation. This is recommended only in patients who were born with a good sacrum, good sphincters, and a malformation with a good prognosis. The results of this procedure vary, with worthwhile continence achieved in more than half of patients (Peña et al. 2007).
In patients with a cloaca, those with a common channel shorter than 3 cm require intermittent catheterization one third of the time. Patients with common channels longer than 3 cm require intermittent catheterization or a continent diversion 70–80% of the time.
Conclusion and Future Directions
Recent progress in the management of anorectal malformations and their associated urogenital deformities allows us to provide an efficient and effective treatment to those patients born with defects with demonstrated good functional prognosis, allowing them to have bowel and urinary control and to have a normal social life (Nam et al. 2016).
For those patients born with complex malformations with poor functional prognosis, there is a full program for bowel and urinary rehabilitation that allows these patients to be artificially clean of stool and dry of urine, which will allow them to have an acceptable social life.
Cross-References
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