Anorectal Malformations Complications

Pediatric Surgery
Dr Marc Levitt discusses ARM Complications with Dr Todd Ponsky
Edited by Nicholas Bruns, MD and Ian C. Glenn, MD

In this episode, Dr. Marc Levitt from Nationwide Children’s Hospital discusses complications of anorectal malformations. This episode is brought to you by the Center for Colorectal and Pelvic Reconstruction at Nationwide Children’s Hospital. Our collaborative team performs more than 1,000 procedures each year for kids from around the world. Visit nationwidechildrens.org/CCPR for more information.

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In this (podcast) episode, Dr. Marc Levitt from Nationwide Children’s Hospital discusses complications of anorectal malformations. This episode is brought to you by the Center for Colorectal and Pelvic Reconstruction at Nationwide Children’s Hospital. Our collaborative team performs more than 1,000 procedures each year for kids from around the world. Visit nationwidechildrens.org/CCPR for more information.

 

Outline

  • Perineal fistula in a male
    • May present with constipation later in infancy, sometimes with dilation of the sigmoid colon and rectum
    • May present with perforation depending on degree of stenosis
    • Anoplasty improves anatomy by creating a correct caliber anus lined by mucosa. Otherwise the perineal fistula does not increase in size as the child grows
Perineal fistula
      • Physical exam
        • Newborn anus should be size 12 Hegar dilator
        • One-year-old anus should be size 15 Hegar dilator
        • Sphincter mechanism should look like a pinkish ellipse

        • The hole is in the anterior portion of the ellipse and anterior to the ellipse altogether
        • A bucket handle may be present (a skin tag with a fistula beneath it)
        • May find beads of meconium (black) or mucus (white) along the scrotal raphe
      • Perineal fistula in a female
        • Criteria that Dr Levitt uses for evaluation
          • Is the hole too close to the vagina (is there an inadequate perineal body)?
          • Is the hole an adequate size?
          • Is the hole centered in the sphincter complex?
          • If the hole is slightly anterior but adequate size and centered in the sphincter complex, then there is no need for anoplasty. If not sure, can perform an exam under anesthesia and stimulate the sphincter complex to determine if the hole is centrally located

        • If a Peña stimulator is unavailable, an anesthesia stimulator may be used with two probes with needles to stimulate the anal complex

          • Recto-urethral fistula
            • There is no anal opening, although there may be an anal dimple
            • Many patients may urinate meconium which is diagnostic
          Rectourethral fistula
            • Do not know what level the fistula is
            • Difficult to visualize with laparoscopy due to the fistula being beneath the peritoneal reflection
            • Dr. Levitt feels that the safest approach is with colostomy and distal colostogram. Exception is the patient with a low rectum on a cross table lateral film. This may be repaired primarily
          • Missed cloaca
            • Important for standardized newborn exam in infants
            • Rectal thermometers helped us to not miss anorectal malformations in the past
            • Clitoromegaly can be seen in an isolated urogenital sinus without an anal malformation
          • Colostomy problems
            • Surgeon opened colostomy too distal in the sigmoid colon, restricting the ultimate pull-through

            • Incompletely diverting loop
              • If a loop is too flat, stool may pass to the distal segment and lead to urinary tract infections.
              • There has been recent literature that shows that diverting loops were not associated with higher rate of UTI, but Dr. Levitt feels these may have been very well constructed loops.
              • Dr. Levitt prefers separated stomas so that stool cannot pass across to the distal segment
            • Transverse colostomy
              • May prolapse
              • If there is a large recto-urethral fistula, the left colon absorbs urine resulting in acidosis
              • Difficult to clean out meconium in the OR
              • Difficult to perform a distal colostogram
            • Proximal sigmoid colostomy
              • Dr Levitt prefers to perform a proximal sigmoid colostomy with a small, flat mucus fistula, separated from the proximal colostomy. He prefers to perform this with laparoscopy through the incision.
              • Prolapse is related to the anatomy of the colon. Since the left colon is fixed to the retroperitoneum, a proximal sigmoid colostomy rarely prolapses
          • Distal colostogram
            • It is important to have a radiologist that is comfortable with the procedure
            • Should determine height of the rectum and if there is a relation to the urinary tract
            • Common mistakes
              • Not enough contrast can falsely give the impression that the rectum is high and/or that there is no fistula. If there is a flattening of the rectum at the pubo-coccygeal line, this may be an indicator that more contrast is needed to overcome this

            • If the urethra is looked at as an "elbow” or "reverse C”, then the type of fistula can be determined by the relation to the urethra
              • At or below = recto-bulbar fistula
              • Above = recto-prostatic fistula
              • At bladder neck = recto-bladder-neck fistula
            • If rectum is bulbous, it may be best approached by PSARP
            • If tapered, it may be better to use laparoscopy
          • Identifying the distal rectum
            • From posterior sagittal approach, may incidentally encounter the bladder neck
            • This can be avoided by performing a proper colostogram and knowing the location of the rectum
              • Rectum distal to the coccyx – bulbar
              • Under the coccyx – prostatic
              • Not in posterior sagittal plane – bladder neck
            • Using a gastroscope through the mucus fistula to allow for transillumination has been described
          • Laparoscopy
            • Laparoscopy is preferred for higher lesions (bladder neck and high prostatic fistulas)
            • Problems with laparoscopy
              • May cause trouble with dissecting a rectum that is too low, resulting in leaving too much distal remnant or invasion in the urinary tract
              • Passage of trocar through perineal incision can be problematic. Dr Levitt prefers to make a 3-4 cm posterior sagittal incision
              • Higher lesions can be difficult to preserve blood supply of the distal colon. It is important to preserve the IMA
          • PSARP
            • Posterior sagittal approach is preferred for lower fistulas (bulbar and lower prostatic)
            • It is important to demarcate the anal sphincter complex prior to making incision in order to recognize landmarks during anoplasty. This is done by drawing around the pink ellipse where there is stimulation
            • If an anoplasty was incorrectly placed and the child has good prognosis for bowel control, the anoplasty should be redone to place the opening in the sphincter complex
            • Problems with posterior sagittal incision
              • May encounter other structure without adequate identification of the distal rectum on colostogram preoperatively
              • If PSARP is done for a rectum that is too high, may inadvertently pull down other structures such as bladder neck
          • Rectal prolapse
            • Tacking the rectum to the posterior muscle complex may reduce prolapse
            • Proper closure of the levators and posterior wall muscles may prevent prolapse
            • Occurs in approximately 3% of cases
            • May cause bleeding and mucus expulsion
            • May cause incontinence
            • Treat with full thickness excision with reattachment of colonic mucosa to anal skin. For circumferential prolapse, this may be done as two outpatient procedures (180 degrees x2)
          • Perineal body dehiscence
            • Key is proper rectal mobilization with complete separation of the anterior rectal wall from the posterior vaginal wall. Not doing this can result in tension, leakage, and dehiscence
            • Secure closure of the perineal body is important with 3-0 suture in an infant and 4-0 suture on the skin
            • Postoperative treatment is NPO for 7 days with 10% dextrose IV solutions. Recently Dr Levitt has started doing clear liquids for 1 week to prevent hard stool
            • Hard stool from early return to regular diet may lead to dehiscence.
            • For 7 days postoperatively, daily exams of the perineal body are performed. If it starts to dehisce, may take the patient back to the OR to resuture
          • Postoperative soiling
            • Evaluation
              • First question is does the patient have potential for bowel control?
              • 3 factors
                • Original type of ARM
                • Quality of sacrum
                • Quality of spine
              • Bulbar fistula with sacral ratio of 1 and normal spine has good prognosis for bowel control
              • Bladder neck fistula with sacral ratio of 0.4 and spinal abnormality such as tethered cord or myelomeningocele has poor prognosis
            • Perineal exam (subjective)
              • Good anal wink
              • Good musculature
            • Bowel management with enemas is used first to gain confidence for the patient
              • When older, the patient can be switched to laxatives. If they don’t succeed, they should remain using enemas
              • If unsuccessful off of enemas, consider anterograde option such as Malone stoma

              • Consider redo pull-through when anatomy is not correct and there is good prognosis for bowel control
                • Anal stricture
                • Imperfectly located anus outside of sphincter
                • Rectal prolapse
                • Posterior urethral diverticulum or remnant of the original fistula

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