Myelomeningocele:
Prenatal and Postnatal Treatment
and Complications
Alyssa Brzenski
Case
• A 25 year old G1P0 at 18 weeks gestation,
with no previous past medical history, was
found during routine screening to have a fetus
with T12-S1 myelomeningocele(MMC). The
fetus, during a detailed prenatal ultrasound, is
found to have Arnold-Chiari malformation but
no other congenital abnormalities.
What is Spina Bifida?
Varying Neural Tube Defects
Spina Bifida
Basics of MMC
• 3.4:10,000 births
• Related to low folate levels, anticonvulsants
(carbamazepine, valproic acid)
• Previous child with same partner is a risk
factor
Co-morbidities
• Sensory motor deficits
• Bowel and Bladder Incontinence
• Arnold Chiari Type II
– Caudal displacement of cerebellar vermis, fourth
ventricle, and lower brainstem
• Hydrocephalus
• Cognitive delay
– Lower risk if no VP Shunt needed
Co-morbidities
Latex Allergies
• All patients with MMC are labeled as latex
allergic
• High rates due to recurrent procedures
including urinary catheterization
• Cross reaction to avocados, banana, passion
fruit, kiwi, banana
Management of Myelomeningocele
Study
• What treatment would you recommend?
• How would you anesthetize the mother and
fetus for the fetal surgery?
• What precautions would you take for a postnatal repair? Anesthetic plan?
Mid-gestational Open
Fetal Procedures
• Significant risk to Mom– Hemorrhage (13% required transfusion)
– Infection (9% developed chorioamnionitis)
– Pulmonary Edema (28%)
– Premature delivery
– Uterine Rupture
• No direct benefit to Mom
Maternal Physiology
• Physiology of Pregnancy
– Airway/Pulm
• Smaller swollen airway
• Decreased FRC, Increased Oxygen Consumption
• Respiratory Alkalosis
– Cardiac
• Decreased SVR
• Increased CO
• Left Uterine Displacement
– GI
• Full Stomach
– MAC
• Decreased anesthetic requirements
Fetal Physiology
• Cardiac– Fetus heart rate dependent
– Slowing during the procedure detrimental
• Heme– Fetal Blood Volume= 120-160 mL/kg
– Hgb = 11.5-12.5 g/dL
– Fetal synthesis of clotting factors decreased
• Oxygen Delivery
– Dependent on placental perfusion
• Thermoregulation
– Fetus unable to maintain temperature
– Must warm any fluid administered to mom and amniotic fluid
replacement
Mid-gestation Fetal Surgery
• Epidural for Mom- post-op pain control
• GA for MOM during the procedure with
maintence of Uterine-placental perfusion
• Must have profound uterine relaxation- Can use
high inspired volatile (2MAC) +/- nitroprusside
• Fetus paralyzed and monitored during surgery
• Minimize fluid administration to avoid pulm
edema
• Mom must receive tocolysis prior to awakening
and will be monitored for pre-term labor
Post-natal MMC Repair
• Infants repaired early after birth
• Must be cautious to not injury the neural tissue
during moving or intubation
• Routine ASA monitors
• Prone position for repair
• May or may not receive VP Shunt at the same
time
• Typically remain intubated as infant should not lie
supine for the first day
VP Shunts have Complications
Sources
•
•
•
Adzick S et al. A Randomized Trial of Prenatal vs Postnatal Repair of Myelomeningocele. New England Journal of Medicine
2011; 364: 993-1004.
Golombeck K et al. Maternal morbidity after maternal-fetal surgery. AM J Obstet Gynecol 2006; 194: 834-9.
Ferschl M et al. Anesthesia for In-utero repair of myelomeningocele. Anesthesiology 2013; 118: 1211-23.