Pediatric Imperforate Anus (Anorectal Malformation) Follow-up

Updated: Aug 08, 2016
  • Author: Nelson G Rosen, MD, FACS, FAAP; Chief Editor: Carmen Cuffari, MD  more...
  • Print
Follow-up

Further Outpatient Care

See the list below:

  • Children with an anorectal malformation require close follow-up for life. Continuity of care is essential in the growing years and into adulthood, as the children deal with issues relating to continence and constipation.

  • Following the initial colostomy, further investigations in preparation for definitive operation, such as distal colostography or repeat renal ultrasonography, are performed in an outpatient setting.

  • Following definitive operation in either the neonatal period or after colostomy, follow-up is necessary 2 weeks after surgery. Parents are often instructed as to how to obtain a set of Hegar dilators, which they are to bring to the first postoperative visit. At that visit, the surgeon measures the size of the anus and instructs the parents how to perform the daily dilations. These dilations continue until the anus has reached its goal size. At this time, the colostomy may be closed if one was performed.

  • Patients with cloacal anomalies need specialized follow-up care after puberty to assess sexual function and to correct genitourinary problems.

    • Some girls who have undergone surgical correction for cloaca have incompletely canalized fallopian tubes and can develop painful cystic collections of menstrual blood following menarche. This condition sometimes requires surgical intervention. A pediatric gynecologist can be extremely helpful for these girls and can suppress menstrual blood production through exogenous hormone administration until a clear treatment strategy is established.

    • Only within the past 20-30 years have significant numbers of girls with cloaca undergone definitive repair. A few have become pregnant. While this is miraculous, the delivery process should include close involvement of the pediatric surgeon who performed the original repair, if possible. If this is not possible, a surgeon experienced in cloaca repair should be consulted. Caesarean delivery is the only safe way to avoid damage to tissues that originally required complex reconstruction.

  • Some children present with prolapse during the toilet-training years. Eliminating constipation as a cause helps identify children who need surgical trimming of prolapsed mucosa.

  • Visits for constipation are frequent, and it is best treated with a regular preventative regimen that includes diet, fiber, and laxatives for as long as they are needed. Dietary water does not influence stool quality in a healthy child.

Next:

Further Inpatient Care

See the list below:

  • After initial colostomy, the child is able to eat and grow, and any other associated malformations may be addressed. Most patients are discharged once their ostomy has started to function and they tolerate a regular diet.

  • Following definitive repair, inpatient course is dictated by the presence or absence of a colostomy.

    • If a child has been diverted with a colostomy prior to definitive repair and the repair is effectively completed using a posterior sagittal incision without laparotomy, the postoperative course is usually brief. The child may eat after the anesthesia wears off and requires a short hospitalization with perioperative antibiotic administration.

    • Complicated repairs that require laparotomy also require more lengthy postoperative courses. These children usually require several days before intestinal function returns and a diet may be resumed.

    • Repairs made without a colostomy may be treated with a "medical colostomy," meaning the child is not fed (ie, strict nothing-by-mouth [NPO] status) and a central line is placed for total parenteral nutrition. After an arbitrary period (commonly 5, 7, or 10 d, determined at the discretion of the surgeon in consideration of a host of factors), a diet is resumed and the total parenteral nutrition is stopped. The central line is removed, and the child may then be discharged.

  • Following ostomy closure, the child usually remains in the hospital for 2-3 days until intestinal function returns. Diet is then resumed, and the child may be discharged.

Previous
Next:

Inpatient & Outpatient Medications

See the list below:

  • Routine pain medications for surgical procedures are warranted. Acetaminophen (15 mg/kg every 4 h) or morphine sulfate (0.05-0.1 mg/kg intravenously every 2-4 h) usually suffices.

  • The usual perioperative antibiotics include ampicillin (50 mg/kg every 6 h), gentamicin (2 mg/kg every 8-12 h), and clindamycin (10 mg/kg every 8 h).

  • Many laxatives have been used to control constipation in these patients. Senna comes in various forms and can be highly effective, although dosage must be individualized. The clinician must be personally engaged and must establish an effective dose response for each patient on a case-by-case basis.

  • Balanced electrolyte solutions have been used for years as a bowel preparation for surgical procedures. These solutions have only recently been made available in powdered form for mixing at home and for use as a laxative (under the name MiraLax or GlycoLax). These nonstimulant laxatives are very palatable to children because they dissolve in any beverage with minimal impact on taste.

  • In children who require urinary prophylaxis, standard medications include amoxicillin (first-line medication in newborns), nitrofurantoin, and trimethoprim/sulfamethoxazole (not used in babies aged < 2 mo). To ascertain a prophylaxis dose for one of these antibiotics, calculate a treatment dose based on the normal administration interval (2, 3, or 4 times per day) and then administer that same dose once per day. For example, if the amoxicillin treatment dose is 20-50 mg/kg/d divided every 8 hours and a patient weighs 10 kg, the normal dose may be 30 mg/kg/d (which falls within the recommended range). Because the patient weighs 10 kg, the dose is 100 mg every 8 hours. The prophylaxis dose would then be a once-daily dose of 100 mg.

Previous
Next:

Transfer

See the list below:

  • Proper consultation and surgical management are important. Transferring these patients to a facility that provides pediatric surgical care aids in proper classification, diagnosis, and management. Optimal resources for the care of these children includes a pediatric surgeon with experience in anorectal malformations, a pediatric urologist, a pediatric anesthesiologist, a critical care specialist, and a neonatologist.

Previous
Next:

Complications

Pitfalls abound in the diagnosis and treatment of children with anorectal malformations. A logical approach and an experienced eye are essential for starting the child down the right path from the outset. Complications, while sometimes unavoidable, can have devastating ramifications with respect to a child's chances for urinary and fecal continence.

The following are a few of the most common issues encountered at pediatric colorectal centers:

  • Primary repair without colostomy: Although certain malformations can be primarily repaired by an experienced pediatric surgeon in the neonatal period without the protection of colostomy, more complex malformations should be treated with colostomy at the initial operation. Primary neonatal operations do not afford the surgeon the benefit of distal colostography to help clarify anatomy. This has resulted in devastating injuries that could have been avoided with a staged approach (colostomy, followed by definitive operation, followed by colostomy closure) with appropriate diagnostic studies.

  • Colostomy type and position: The ideal colostomy position in children with an anorectal malformation is at the junction of the descending and sigmoid colon. The colostomy should be completely divided, with the ends spaced far enough apart to ensure that the mucous fistula is not located within the ostomy appliance. This prevents continued soiling of the urinary tract by feces, which can result in urinary infection. Loop colostomies are never completely diverting and put a child at risk for urinary sepsis. Transverse colostomies seem to be associated with a significant degree of mucous accumulation in the long defunctionalized segment, resulting in chronic distension and dysmotility similar to that seen in children with atresias. Desire to perform laparoscopic pull-through should not be a primary factor in the decision to perform colostomy. [8]

  • Intestinal perforation

    • This complication can arise during any phase of management.

    • In children diagnosed with imperforate anus at birth, 24 hours is allowed to pass prior to surgical treatment if perineal fistula (or other visible malformation, eg, vestibular fistula or cloaca) is not evident and urinalysis findings do not show meconium. This allows the distal colon to distend a bit, and meconium occasionally leaks out on the perineum from a tiny perineal fistula. This waiting period is advocated by the most experienced surgeons and should not increase the risk of perforation prior to repair or colostomy. Although exceedingly rare, some children have perforated during this period.

    • Perforation has also occurred during anal dilations. Dilations should always be performed first by the surgical staff. Dilation (performed instead of anoplasty) should be performed only by the surgical staff in extremely low birthweight premature babies. Parents may be taught how to dilate larger babies but must be closely supervised.

    • Perforation is minimized by appropriately positioning the colostomy while avoiding a transverse colostomy.

  • Operative complications: Correction of malformations, even those that some surgeons may describe as minor, requires significant experience, a keen eye, and a sensitive hand. Devastating complications (eg, complete dehiscence, postoperative fistula, missed fistula, urologic injury, ischemia) can render a child who may have been continent after a successful operation completely incontinent. Thus, these children should be directed to a subspecialist with a special interest in this area at the earliest possible opportunity.

  • Stenosis: This is a narrowing of the new anus. A tight ring of scar tissue forms instead of a soft and stretchable anus. This is a devastating complication and usually requires complete surgical repair. A regular schedule of slow progressive dilation of the neoanus prevents stenosis. Weekly dilations increase risk of stenosis. If the dilations are spaced too far apart, the anus can narrow between the dilations. Large dilations provoke tears. Tears heal with scar tissue, which causes stenosis.

  • Undrained hydrocolpos

    • Many baby girls born with cloaca have a very large mucous-filled vagina. This may appear as a giant cystic structure on prenatal ultrasonography. Ultrasonography should be performed at birth to look for such a cystic mass. If present, it must be drained either from below (through the cloaca) or at the time of colostomy using a vaginostomy tube. If it is left undrained, complications ensue.

    • Hydrocolpos can large enough to obstruct the ureters. Some children with undrained hydrocolpos have undergone vesicostomy and ureterostomy, when simple drainage of the hydrocolpos would have sufficed.

    • Hydrocolpos can also become infected. If the vagina perforates, it usually scars and becomes unusable, often necessitating vaginal replacement

  • Constipation

    • Many children who have undergone anorectal malformation repair develop constipation. This must be prevented by strong parental counseling and diligence to ensure the child clears the rectum daily. Constipation on its own is not a complication. The complication is not preventing the constipation through close follow-up and parental counseling.

    • Once constipation develops, the distal colon can become dilated, which exacerbates the constipation because the dilated bowel has poor motility. The end result is termed encopresis. Fecal impaction forms, and liquid stool leaks around it constantly, leaving the child incontinent. This can be treated but is best prevented.

    • Incontinence: Many children who have malformations associated with poor prognosis develop fecal or urinary incontinence, even after a flawless operation without complication. While "the plumbing" may seem to be a relatively simple matter of rearranging some tubes, continence is a complex state that requires a delicate balance of nerves, anorectal and colonic motility, and sphincter muscles. Parents should be given realistic expectations and should be made aware of all options, including bowel management or continent diversion and intermittent catheterization, should incontinence occur.

Previous
Next:

Prognosis

See the list below:

  • All patients who have an anorectal malformation with no significant life-threatening comorbidity should survive. Therefore, prognosis is best determined based on the probability of primary fecal continence.

  • Continence, defined as voluntary bowel movements with minimal soiling, varies based on primary and associated malformations. A tethered spinal cord or another spinal malformation, such as hemivertebrae or spinal dysraphism, may significantly increase the risk of incontinence.

  • Surgical complications worsen the chances for primary continence, although this effect is difficult to quantify. Reoperation significantly decreases the opportunity for primarily continence.

  • All children with a perineal fistula should be continent. Spinal malformations are exceedingly rare in this group.

  • Approximately 90% of girls with a vestibular fistula have voluntary bowel movements. [9]

  • Approximately 80% of boys with a bulbar urethral fistula have voluntary bowel movements, whereas 66% of boys with prostatic urethral fistula have voluntary bowel movements. Only 15% of boys with bladder-neck fistulas have voluntary bowel movements. [9]

  • Children with imperforate anus without fistula have a 76% chance of having voluntary bowel movements. [9]

  • The chance of fecal and urinary continence in girls with cloaca varies based on the length of the common channel. Girls with a short common channel and no associated urological or spinal malformations can have excellent results, with as many as 75% of girls developing voluntary bowel movements. Urinary or fecal continence is very unlikely in girls with long–common-channel cloacae, sacral malformations, and a tethered spinal cord. [9]

  • The best determination for future continence is observation of function. A child who constantly leaks stool or urine constantly will probably not improve by school age and may benefit from early bowel management or intermittent catheterization. If a child is able to hold urine, stool, or both, the best course is to observe his or her function.

  • Regardless of what the child will be capable of in the future, cleanliness of urine and stool must be established before a child enters a school peer group. No child should be allowed to suffer the stigma of being the "smelly" child simply because their physician or parents were unable to accept the child's incontinence or because they were not yet ready to proceed. Even in the worst cases, hope remains. However, the decisions made must be practical and must allow the child to seamlessly fit in with their peer groups.

Previous