Myelomeningocele closure and ventriculoperitoneal shunt malfunction
Stem
A 1-day-old boy, 3.2 kg, born at term, has an open lumbosacral myelomeningocele, 6 cm across, covered with a moist dressing. Head ultrasound shows mild ventriculomegaly. He breathes comfortably on room air with no stridor, and feeds have been held. He has one peripheral IV. Neurosurgery plans closure this morning.
Question
How will you anesthetize him for the closure?
Ideal answer
HeadlineA newborn with an open neural tube: latex-free from birth, protect the sac at induction, expect Chiari II airway and breathing problems, and keep him warm.
- Latex-free room, gloves and catheters, because these children become sensitized with repeated exposure, so precautions start now.1,2
- Induce lateral or supine on a donut ring, sac off the table, video laryngoscope ready, head neutral, because neck flexion pushes the tonsils down.1,3
- Intubate, then prone with every pressure point padded, volatile titrated gently, small fentanyl doses and no long-acting morphine, because postoperative apnea is the risk.1
- Heat and fluid: radiant and forced-air warming, a second IV, isotonic fluid with dextrose continued.1
- Extubate awake and supine, then watch closely for apnea and raised intracranial pressure.1
Watch for: stridor, apnea and hypothermia; brisk bleeding with a large sac.
Breaking down the answer
- Timing — closure within 24–48 hours of birth, and certainly within 72, limits infection.1,2 Changes if: prenatal repair was done; the neonatal case becomes shunt-focused.
- Chiari II — 70–90% develop obstructive hydrocephalus needing a shunt, often revised repeatedly; brainstem dysfunction brings swallowing problems, vocal cord paralysis, stridor and apnea.2 Changes if: stridor before surgery; I plan postoperative ventilation.
- Relaxants — usually not contraindicated; I discuss them with the surgeon, who may stimulate roots.1 Succinylcholine is not contraindicated: a congenital lesion does not cause denervation hyperkalemia.4 Changes if: the surgeon wants motor responses; a short-acting dose.
- Losses — the open defect drives large insensible losses; albumin helps in larger resuscitations, and big lesions may need transfusion.1 Changes if: central access is needed for a large lesion.1
- Associated anomalies — renal, malrotation, tracheoesophageal and cardiac defects, syringomyelia, later scoliosis.1 Changes if: a murmur; echo before elective surgery.
- After closure — prone ventilation for 1–3 days is not uncommon.2 Changes if: a large resuscitation or instability; he stays intubated.1
Follow-up question
Four years later the same child has two days of headache and vomiting and is now drowsy. Heart rate is 62, blood pressure 128/80, and his eyes are deviated downward. Neurosurgery wants to revise his shunt now. How do you anesthetize him?
Follow-up answer
HeadlineShunt failure with signs of impending herniation; I tell neurosurgery this is an emergency and avoid anything that raises his pressure.
Latex-free room, no sedative premedication, and no extreme neck flexion or extension.3 He is vomiting, so a rapid sequence induction with propofol and rocuronium, avoiding coughing and hypoxia. If herniation is imminent or surgery is delayed: end-tidal CO2 28–35 mmHg, mannitol 0.5–1 g/kg or 3% saline 2–5 mL/kg, and a shunt tap by neurosurgery.5 I support cerebral perfusion with norepinephrine if needed.5 I reassess pupils, heart rate and pressure, expecting hypotension once the ventricles decompress.
Pitfalls that cost points
- A latex urinary catheter or glove anywhere in the room.
- Calling chronic stridor laryngomalacia when it is vocal cord paralysis from brainstem compression.
- Accepting a normal CT as proof the shunt works.5
Rapid-fire
Q: Which symptoms together make shunt dysfunction very likely? A: Drowsiness, headache and vomiting.5
Q: Which signs mean a neurosurgical emergency? A: Falling consciousness, bradycardia, hypertension, papilledema and sunsetting eyes.5
Q: Why can a CT look normal with a blocked shunt? A: Slit ventricle syndrome: stiff, small ventricles do not dilate.5
Q: How is myelomeningocele prevented? A: Folic acid 400 mcg daily before conception.2
Q: Where are most lesions? A: About 90% are lower lumbosacral.2
Numbers to know
| Item | Value |
|---|---|
| Timing of closure | Within 24–48 h (no later than 72 h)1,2 |
| Hydrocephalus needing shunt | 70–90%2 |
| Hyperventilation for herniation | ETCO2 28–35 mmHg5 |
| Mannitol 20% | 0.5–1 g/kg over 10–20 min5 |
| 3% saline | 2–5 mL/kg over 5–10 min5 |
| Postoperative prone ventilation | 1–3 days not uncommon2 |
Links
- Neonatal physiology and resuscitation, Raised intracranial pressure: evaluation and reduction, anaphylaxis, Temperature monitoring and intraoperative hypothermia, Pediatric airway anatomy and equipment
- SPA case guide: myelomeningocele
Sources
- 1.Myelomeningocele: SPA Case Guide · Society for Pediatric Anesthesia, 2022 · www2.pedsanesthesia.org
- 2.Myelomeningocele · OpenAnesthesia, 2023 · openanesthesia.org
- 3.Arnold-Chiari malformation (anesthesia rare-disease summary) · UCLouvain Anesthesia Weekly · sites.uclouvain.be
- 4.Failure of succinylcholine to alter plasma potassium in children with myelomeningocoele · Anesthesiology (Dierdorf, McNiece, Rao, Wolfe, Means), 1986 · europepmc.orgAnesthesiology 1986;64:272-3. Brief report; bibliographic record and title read (no abstract): succinylcholine did not raise plasma potassium in children with myelomeningocele.
- 5.Ventriculoperitoneal shunt problems (Emergency Department guideline) · Perth Children's Hospital, 2026 · pch.health.wa.gov.au
Facts on this page were checked against these sources on Oct 22, 2026. Guidelines change; confirm doses against current institutional protocols.