Imperforate anus

Disease Description (Causes and Symptoms)

• Definition: A congenital condition in which the anus is absent or is not located within the normal sphincter complex (imperforate anus, anal atresia).
• Causes/pathophysiology: Due to incomplete separation of the urethra and rectum (urorectal septum) during the fetal period, the end of the rectum fails to descend to its normal position or forms a fistula with the urethra, vagina, or other structures. Depending on the location of the lesion, it is classified as low (closer to the skin) or high (closer to the abdominal cavity).
• Main symptoms:
  • Failure to pass meconium immediately after birth
  • Abdominal distension over time (signs of intestinal obstruction)
  • No anal opening in the external perineum or an opening in an abnormal location (in boys, toward the urethra, scrotum, or perineum; in girls, a fistula to the vestibule or vagina, etc.)
• Associated anomalies: Other congenital anomalies involving the esophagus and airway, spine/sacrum, heart, kidneys, limbs, and other organs (for example, VACTERL association) may occur, so additional evaluation is necessary.

Treatment Methods (Standard Treatment, Surgery, Lifestyle Management, and Precautions)

• Goal: To reconstruct the anus in an anatomical position that allows bowel control while minimizing damage to the sphincter and nerves.
• Surgical principles:
  • Low anal atresia: Anoplasty through the perineum can be performed immediately during the neonatal period (for example, perineal anoplasty or single-stage PSARP).
  • High anal atresia: Initially, a colostomy is created to allow stool passage. Later, definitive anorectal reconstruction (PSARP or laparoscopic-assisted surgery) is performed, taking into account the institution, weight, and developmental status, usually after several months, followed finally by colostomy closure.
  • Recently, laparoscopic-assisted anorectoplasty has been used for high lesions.
• Medications/adjunctive treatment:
  • Pain management, antibiotics, and other treatments as needed after surgery
  • Bowel management: Laxatives, enemas, bowel training, and a bowel management program (particularly for controlling constipation and fecal incontinence)
• Lifestyle management and wound/stoma care:
  • When using a colostomy, manage the pouch, protect the skin (using skin protectants and barrier wafers), and change it regularly (standard: changing the skin barrier wafer once a week is recommended; emptying the pouch when it is at least one-third full, etc.)
  • Parent education: Visit the hospital immediately if abnormal signs occur, such as abnormalities of the wound or skin around the stoma, fistula discharge, high fever, vomiting, or acute abdominal pain.
• Precautions/risks of complications:
  • Wound infection, fistula, and anal stenosis
  • Fecal incontinence (the risk is increased particularly in high anal atresia; approximately 10–30% in the literature and standard reports, with approximately 20% mentioned in the provided materials) and chronic constipation
  • Possible urinary tract infection (when a fistula is present), urethral or vaginal injury, and kidney problems
• Long-term follow-up: Assessment of growth and bowel control, urinary tract and kidney function tests, and orthopedic and neurosurgical follow-up (when sacral or spinal abnormalities are identified)

Checklist Before an Outpatient Visit (Including Useful Items to Bring and Sample Questions)

• Useful items to bring:
  • Previous surgical and hospitalization records (operative log, op note), and photos related to the colostomy (stoma location and skin condition)
  • Previous test results: neonatal invertogram/abdominal X-ray, abdominal ultrasound, urodynamic study, renal ultrasound, echocardiography, spinal imaging (MRI/ultrasound), etc.
  • A list of currently used medications and supplements
  • Bowel movement records: frequency and characteristics (hard stool, watery stool, leakage, etc.), and details and effects of enemas and medications
  • Growth records (weight and height), and vaccination status
• Items to check yourself before the outpatient visit:
  • Whether there is redness or disease of the skin around the stoma
  • Whether there has recently been fever, vomiting, abdominal pain, or urinary symptoms (frequent urination or hematuria)
  • The child’s progress with bowel training
• Key information to tell the doctor first at the outpatient visit (examples):
  • “I have organized a record of how my child’s bowel movement pattern has recently changed, including its frequency and characteristics.”
  • “The skin around the stoma has been repeatedly irritated over the past two weeks (photos attached).”

General Sample Questions to Ask the Doctor

• “Is my child’s lesion high or low? How does this affect the prognosis?”
• “Among the surgical options (staged surgery versus one-time reconstruction), which method do you recommend for my child, and why?”
• “If fecal incontinence or constipation develops after surgery, what treatments (medications, enemas, or behavioral therapy) do you recommend?”
• “How should we manage the colostomy, and what should we do if skin complications develop?”

Disease-Specific Sample Questions (1–2)

• “In my child’s case, based on the imaging and surgical findings, what is the condition of the sphincter and sacral structures, and what does this mean for the prognosis of bowel control?”
• “Have tests for potentially associated kidney, heart, and spinal abnormalities already been performed, and could you recommend what additional tests are needed?”

Note: Because this is a congenital condition, prevention is limited. Early diagnosis, appropriate surgery, and long-term follow-up care are important for improving the prognosis.