MENINGOMYELOCELE

Speaker: Dr Bhagirath.S.N

Moderator: Dr Sarika

Meningomyelocele

• Incidence: 1 in 1000 live births

• Most common congenital primary neural defect

Meningo: involving the meninges Dura Arachnoid

Myelocele: involving the neural components Neural placode Nerve tissue roots CSF

Components of a meningomyelocele

Embryology

Neural tube development-failure of closure of neural tube causes a meningomyelocele

Embryology…….(contd)

It presents most commonly over the lumbar, sacral vertebra as a cystic mass

Meningomyelocele

•Coexistent morbidities:

Orthopedic problems in the child

Urologic complications

• Antenatal diagnosis

Ultrasonography

biochemical tests:

α fetoprotein levels in the maternal serum and amniotic fluid

Associated Conditions-Arnold Chiari Malformation•Brain stem anomaly

•Caudal displacement of

Cerebellar vermis

Medulla oblongata

Cervical spine

Kinking of the medulla

Obliteration of cisternamagna

• Clinical presentation

Stridor, Apnea, bradycardia

aspiration pneumonia

sleep disordered breathing

pattern

vocal cord paralysis

Lack of co-ordination &

spasticity

Associated Conditions-Arnold Chiari Malformation….(contd)• small sized skull housing a normal sized posterior fossa

Approach to a meningomyelocele patient….

• To operate within 24 hours-reduces the neurological deficits

• Close the defect and place a shunt

• or delay placing a shunt and instead operate once hydrocephalus sets in

• Intra uterine procedure is less favoured

• Posterior fossa decompression should always be a last resort

Meningomyelocele-preoperative care

•An exposed neural placode risks

Trauma

Continous CSF leakage-countered by full strength balanced salt solution

place a soaked gauze to prevent desiccation

Maintain extracellular fluid

Avoid hypothermia

Meningomyelocele-Peri operative careAnesthetic technique

1. Positioning:

Supine: the defect ought to rest in a “doughnut” to

minimise trauma.

Lateral: leads to difficult intubation

Prone: Care is taken to avoid pressure on epidural venous

plexus to maintain bleeding and allow adequate ventilation.

2. The child usually has an IV cannula in place with maintenance fluids.

3. Premedication—atropine 20 mcg/kg IV prior to induction if desired.

4. Induction is IV or inhalational as preferred. The child may need to be

supported on a cushion or jelly ring to avoid pressure on the lesion

or placed in the lateral or semi-lateral position depending on the

exact anatomy.

Meningomyelocele-Peri operative careAnesthetic technique

5. Endotracheal intubation with an armoured ETT and IPPV are required.

6. Maintenance is with volatile agents in oxygen and air or nitrous

oxide.

7. Consider arterial and central line depending on the size of the lesion.

8. The patient is positioned prone for surgery. Rolls of soft material or

jelly bolsters are placed under the shoulders and pelvis to allow free

abdominal movement during ventilation.

9. The extremities are padded.

10.The surgeon may wish to stimulate nerves during the procedure.

Discuss this before giving a long acting neuromuscular blocker.

11.Blood loss is not usually a problem but some large lesions require

extensive undermining of skin to fashion a flap or flaps when

bleeding does become an issue.

Meningomyelocele-Peri operative careAnesthetic technique

12.The surgical site is usually infiltrated with LA and adrenaline to

ensure haemostasis. Additional opioid analgesia (morphine sulphate

25-50 mcg/kg or fentanyl citrate 1-2 mcg/kg) can be given if this is

inadequate. The sensory level is usually unclear at this point so

analgesic requirements are variable.

13.IV antibiotics are given according to surgical request or local

protocol.

14.If stable, extubate at the end of procedure.

Meningomyelocele-Post-operative careWatch out for

• Stridor

• Apnea

• Bradycardia

• Cyanosis

• Respiratory arrest

Secondary to brain stem herniation

If shunting is not done, then watch out for

symptoms associated with hydrocephalus•Lethargy

•Vomiting

•Seizures

•Apnea

•Bradycardia

•Cardiovascular

instability.

If symptoms worsen, proceed with shunting