Evaluation of Myelomeningoceles in Children

Prenatal Preparation

  • Consultation with parent(s): The evaluation of myelomeningocele in children starts with prenatal neurosurgical consultation.
  • Planning for perinatal period: The neurosurgeon should be notified as soon as the delivery date and time are identified.  There is no convincing evidence that C-section or vaginal delivery is preferable.

Examination

  • Examine placode: Measure the size of the neural placode and the amount of skin available for closure.
  • Examine for hydrocephalus: Measure and plot head circumference. Examine and document fontanelle. Check for splaying of any or all sutures to include squamosal suture. Symptoms from the Chiari II malformation, which may be devastating, include defects in the lower cranial nerves with failure to breathe or swallow.
  • Neurological level of myelomeningocele: Neurological exam includes a motor, sensory and reflex examination of the legs. The level of the neurologic dysfunction correlates roughly with anatomic level of myelomeningocele. Where there is significant variation between functional and anatomic level, the functional level is usually worse. The examination also includes the anus reflexes.  There is abnormal bowel and bladder function in nearly all children. Additional examination of the upper extremity function and cranial nerves is needed to assess the extent of brainstem and cervical spine compromise from Chiari II, hydrocephalus, and syringomyelia.

Laboratory Tests

  • Routine: Only routine basic laboratory tests are required. Standard newborn screening should be completed.

Radiologic Tests

Ultrasound

  • Ultrasound assessment of ventricular size: Head ultrasound can be used to evaluate the ventricular size and need for a shunt at time of closure of the myelomeningocele.
  • Cardiac screening: If a detailed fetal echocardiogram had been performed and the infant is clinically stable, there is no need for postnatal echocardiogram. Otherwise, it is advisable to obtain one prior to myelomeningocele repair.

Regular x-rays

Plain radiographs are often important as they help define the bony deformities in addition to providing important information about the pulmonary and gastrointestinal systems.

  • Spine x-rays: It is reasonable to obtain a plain x-ray of the spine to evaluate for associated spina bifida occulta elsewhere or the bony spicule of a split cord malformation.
  • AP and lateral scoliosis views: The standard spinal radiograph includes both front and lateral views. Follow-up x-rays in the supine and erect positions can be used to evaluate for progression of kyphoscoliosis as the child grows.
  • Quantification of spine curvature: Analysis of the severity of the scoliosis through Cobb angle and other measurements are fundamental not only for observing the behavior of scoliosis over time but also to guide surgical planning as needed. Similar assessments are conducted in cases of hip and foot deformities.
Scoliosis series: Note the spina bifida seen on AP. No segmentation or kyphotic deformities are present.

     

    • Gas patterns on abdominal x-rays: The radiographic study of the abdomen is important in assessing intestinal function and contents (e.g., fecaloma), signs of stomach distention, presence of air in the peritoneal cavity, and the like.
    Plain AP abdominal x-ray: This x-ray shows abdominal distention and pelvic dislocation.. Note wires placed at the time of neonatal kyphectomy.

     

    • Shunt series for catheter integrity: Both are effective at visualizing the integrity and placement of catheters. As stated above, the simple radiograph is versatile, low cost, and easy to obtain, making it a useful adjunct in the diagnosis, monitoring, and treatment of children with spina bifida.

    CT scans

    CT studies, when indicated, are useful in the diagnosis of brain diseases, in particular hemorrhage and ventricular shunt malfunction, as well as pulmonary and abdominal complications such as acute respiratory events and bowel obstruction.  Nonetheless, caregivers are advised to use CT scans sparingly to minimize radiation hazards.

    CT scan showing increased ventricle size: This condition indicates a possible increase in ICP

     

    • Surgical planning: CT scanning, particularly through its multiplanar reconstruction capability, is crucial in the planning of surgical correction of skeletal deformities.
    CT scan of dysraphic spine: The image shows a bony septum in a child with split cord malformation

     

    • Lung parenchyma assessment: Chest CT scans are useful in the detailed assessment of the pulmonary parenchyma to evaluate for pneumonia, atelectasis, and/or and chest restriction due to skeletal deformities.
    • Bowel obstruction, catheter penetration of organs: Abdominal CT scans may assist in the evaluation of patients with abdominal obstruction from fecalomas, cysts, adhesions, or other conditions, and may better assess the possibility of shunt catheter migration into peritoneal organs.

    MRI

    MRI is best used in the diagnosis and follow-up of intracranial malformations and injuries. The brain is evaluated by MRI for ventricular dilatation and the presence of other malformations associated with spina bifida, such as Chiari II malformation or absence of the corpus callosum. Spinal MRI is used for the evaluation of syringomyelia and tethered spinal cord.

    • Baseline MRI: MRI of the brain and spinal cord is often obtained during the initial hospitalization or in the first few months of life.
    • Split cord: The myelomeningocele defect can be associated with a split cord malformation in up to 10% of cases (22). 
    • Chiari II malformations: Chiari II malformations are associated with a constellation of findings that include hindbrain herniation through the foramen magnum, low-lying torcular, elongated fourth ventricle, kinking of the medulla, beaking of the tectum, large massa intermedia, and an incompetent falx with interdigitation of the cerebral hemisphere.
    T1-weighted sagittal MRI: Shown is a Chiari II malformation. Note beaked tectum, elongated brainstem extending into cervical canal, and cerebellar tonsils extending down to the C3 level, marking the outlet of the fourth ventricle. A large massa intermedia can also be seen

     

    • Fast-sequence MRI: The use of fast-sequence or quick-brain MRI allows for radiation-free imaging of the brain and spine without the use of sedation. This methodology provides a safe alternative to CT imaging, reducing radiation exposure in infants and children with hydrocephalus (34).
    Quick MRI of brain: This scan is of the brain of an infant with a myelomeningocele and Chiari II malformation. No sedation was required for this scan due to its speed of acquisition.
    Quick MRI of spine: This scan of the spine of an infant with a myelomeningocele was taken after the repair was done wthout sedation
    MRI of dysraphic spine: Shown is a kyphotic deformity and associated syringomyelia

     

    Nuclear Medicine Tests

    • Not indicated: There is no specific role for nuclear medicine evaluations in the care of children with myelomeningocele.

    Electrodiagnostic Tests

    • Not indicated: There is no specific role for electrodiagnostic testing unless there is clinical concern about cardiac or epileptic problems.

    Neuropsychological Tests

    • Useful for tracking development: The use of neuropsychological testing as a child grows can be tailored to his or her developmental progress, functional goals, and social support.

    Correlation of Tests

    • Development and imaging: As the child grows, neurological symptoms can manifest as a result of shunt malfunction, tethered spinal cord, or syringomyelia. While shunt malfunction should be most considered the most likely cause for new or recurrent neurological symptoms, medical evaluation and cranial/spinal imaging may reveal another cause, such as urinary tract infection and tethered spinal cord.