Myelomeningocele (MMC) is the most relevant clinical variant of spina
bifida - a birth defect resulting in an open vertebral column. The failure of the
lumbosacral neural tube to close during embryonic development may compromise the
spinal cord in utero due to exposure to amniotic fluid and irritation by the uterine wall.
Resulting neurological deficits may vary depending on the spinal level involved. Most
neural tube defects are diagnosed in the second trimester by ultrasound. Early prenatal
diagnosis allows in-utero repair to diminish neurological deficits and the need for
postnatal ventricular shunting. In this chapter, the authors present a brief review of the
pathophysiology of fetal MMC and the various repair options, and their associated
clinical outcomes. Clinical studies suggest improved short-term neurological outcomes
with percutaneous minimally invasive and intrauterine fetoscopic techniques using
endoscopes compared with an open prenatal or postnatal repair. The main limitations of
these modern techniques are preterm premature rupture of membranes (PPROM) and dehiscence or leakage at the MMC repair. Additional benefits may include a lower risk
of preterm labor, reduced need for postnatal revisions, and improved newborn maturity
with higher gestational age. Fetoscopy may also offer better management of the
membranes and primary closure of uterine port sites. The long-term cognitive,
behavioral, and functional outcomes of fetoscopic MMC repair have yet to be
determined. While cesarean section may be required for delivery in subsequent
pregnancies after traditional open prenatal MMC repair to avoid uterine rupture,
fetoscopic methods with externalization of the uterus by maternal laparotomy may
allow spontaneous vaginal delivery at term.
Keywords: Fetoscopy, Lumbosacral neural tube, Myelomeningocele, Neurological deficits, Spina bifida.
