Management of Infants with Myelomeningocoele

 

Reviewed by Colette Muir, Carl Kuschel, Andrew Law (Paediatric Neurosurgery, Starship Hospital), Raewyn Gavin (General Paediatrics, Starship Hospital), Bobby Tsang (General Paediatrician, Waitemata District Health Board) 
October 2005
Clinical Guidelines Back Newborn Services Home Page
Definition Aetiology Incidence Antenatal Issues
Place and Mode of Delivery Postnatal Management Postoperative Care Prognosis

Definition

Thoracolumbar junction 45%
Lumbar 20%
Lumbosacral 20%
Sacral 10%
Other (high) lesions 5%

Aetiology

Incidence

Antenatal Issues

Screening and Detection

  • Alpha feto protein (AFP) from amniotic fluid is very reliable except when the defect is closed.
  • Maternal serum AFP is less reliable, detecting between 50-90% of open anomalies, but is falsely positive in 5%.
  • USS: Diagnosis often made at 16-18 week USS. Often seen as lateral displacement of the spinal pedicles, but the sac may also be visualised.
    • An axial cross section through the fetal skull may demonstrate a “lemon head” shape, with a depression of the metopic suture in the frontal region.
    • Visualisation of the posterior fossa may demonstrate a “banana sign”, observed at the level of the cerebellum and cistern magna. It is caused by herniation of the cerebellar vermis through the foramen magnum, giving the cerebellum the appearance of a banana.
    • USS should evaluate for other structural abnormalities of limbs, brain, kidneys, and other organs.
CoronalSpine.jpg (17363 bytes)  Coronal view of spine

SagittalSpine.jpg (19227 bytes)  Sagittal view of spine

LemonHead.jpg (15065 bytes)  "Lemon" shaped skull

Counselling

Place and mode of delivery

Postnatal Management

General Cares

  1. Avoid latex products (use latex-free gloves for all handling).

Clinical Assessment

  1. Careful clinical assessment.
    • It is unusual, however, for other abnormalities to be present.
  2. Place the infant prone and evaluate the size, position, and appearance of the lesion.
  3. Palpate the fontanelle and sutures for evidence of raised intracranial pressure.
  4. Measure the head circumference.
  5. Evaluate spontaneous movements (note that any stimulation to promote movements should be confined to the upper body, as reflex movements may occur in response to stimulation of paralysed lower limbs and trunk).
  6. Evaluate the level of sensation. This can be determined using an open nappy pin (not a hypodermic needle).
  7. Assess anal tone.
  8. Urine output.
    • Is there dribbling of urine?
    • Is the bladder palpable?

Infection Risk

  1. Antibiotics should be administered as per the Newborn Services policy.
  2. Blood and other cultures are not required unless the baby is clinically unwell.

Fluids/Electrolytes

  1. Remain NBM.
  2. 10% dextrose as per Newborn Services Fluids and Electrolytes policy.
  3. Infants with urinary retention will require urinary catheterisation.

Neurosurgical Referral

  1. Inform the neurosurgical team at the Starship Hospital.
    They will arrange for early transfer and repair of the lesion.

Imaging

  1. Cranial ultrasound scan of brain to evaluate ventricular size and to assess other malformations.
  2. A CT scan or MRI is commonly obtained peri-operatively but will be organised by or on the instruction of the neurosurgical team.
  3. Renal imaging (renal ultrasound scan and MCUG) should be performed in the postoperative period.

Dressings

  1. The baby should be nursed in the prone position.
  2. The sac must be kept covered and moist prior to closure.
  3. Exposure of the tissue to trauma or drying out can lead to a “shock-like” state of the spinal cord.
  4. This needs to be a strictly aseptic technique.
    1. Apply saline soaked Telfa over the sac.
    2. Obtain a Butterfly infusion needle, and remove the needle.
    3. Insert the Butterfly tubing on the layers of Telfa with a second Telfa.
    4. Seal the entire dressing with Tegaderm.
    5. The wound can be irrigated hourly using the fine Butterfly tubing, with small amounts of warmed saline.

Parental Support

  1. Referral to Paediatric Neurosurgical Social Worker will be arranged following surgery.
  2. A Child Disability Allowance form should be filled out.
  3. Useful information for parents can be accessed from the Australian Spina Bifida and Hydrocephalus Association (www.asbha.org.au)

Postoperative Care

  1. Will usually be undertaken on the Neurosurgical and Neurology ward (26A) at Starship Hospital.
  2. A urinary catheter usually remains in situ postoperatively (preferably until renal imaging has been undertaken).

Prognosis

References

1

Improving folate intake in New Zealand: Policy Implications: Ministry Of Health, 2003.
2 Folic acid and neural tube defects: the current evidence and implications for prevention. Ciba foundation Symposium 181:192-208
3 Volpe JJ. Neurology of the newborn 4th ed. WB Saunders Co, Philadelphia 2001
4 Levene MI, Chervanek FA, Whittle MJ (eds). Fetal and neonatal neurology and neurosurgery, 3rd Ed. Churchill Livingstone, London 2001.