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 post-

natal 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.