Anaesthesia for Myelomeningocele Repair; Precautions to be taken

Associated conditions: Hydrocephalus, Chiari II malformation, neurogenic bladder/ bowel, short trachea (Take care to avoid endobronchial intubation)hydronephrosis, malrotation of the gut, VSD, ASD, Craniofacial anomalies (Screen for these in first 24 hours after birth, before taking for surgery; may need ECHO, Renal US) Latex allergy is increased in this population Check electrolytes, RFT

Goals of the surgery: Preservation of neural tissue, reconstituion of a normal intrathecal environment, complete skin closure to prevent CSF leak and meningitis. Concern: Most MMCs leak CSF from time of birth--> risk of ventriculitis--> hence closure is recommended within 48-72 hours after birth

Points to ponder:

Take care in prone position to avoid undue pressure over body parts..facial oedema can occur postoperatively

Warmer should be arranged to avoid hypothermia; control the O.R. temperature

Before induction, protect the back defect with sterile donut or rolls

 In case of large defects local or myocutaneous flaps may be required to close the defect adequately 

Progressive hydrocephalus establishes after closure of MMC

The efficacy of intrauterine meningomyelocoel repair is being explored 

Anticipate lower brainstem dysfunction 

Need for blood replacement is rare in straight forward cases (EBL ~25 mL)

Usual duration: 1.5-3 hours

If complex repair with fascial release and tight abdomen: better to ventilate for first 24 hours; otherwise on-table extubation can be done

Postoperatively, child is usually nursed on stomach or side; head circumference and head USG are used to monitor for progressive HCP, which may require VP shunt

Post operative complications: wound infection, CSF leak, renal failure, respiratory compromise from tight abdomen

Respiratory complications : hypoventilation, sleep apnoea, bronchospasm, laryngospasm, prolonged breath holding as a result of structural derangement of  medullary respiratory control

Cardiovascular complications: bradycardia, hypotension and tachycardia. Brainstem compression and coning causes most of the  cardiac complications including cardiac arrest when Chiari malformation is  associated with MMC.

Delayed recovery has to be anticipated...so arrange for postop ventilation ( Respiratory centre dysfunction, due to brainstem compression, if there, will again, increase the chance of requirement for post op ventilation) 

Check for swallowing, gag reflex before extubation. Extubation should be performed only when the child is awake and breathing well.

Pain score 3-5