In preliminary reports, infants following antepartum defect repair were more likely to have reversal of the Arnold-Chiari II malformation and were less likely to require ventriculoperitoneal shunt placement (Bruner, 1999; Sutton, 1999). Spurred by this, the randomized, multicenter MOMS trial was conducted (Adzick, 2011). Criteria for trial participation included: (1) a singleton fetus at 19.0 to 25.9 weeks' gestation; (2) an upper myelomeningocele boundary between T1 and S 1 conirmed by fetal magnetic resonance (MR) imaging; (3) evidence of hindbrain herniation; and (4) a normal karyotype and no evidence of a fetal anomaly unrelated to the myelomeningocele. Women at risk for preterm birth or placental abruption, those with a contraindication to fetal surgery, and women with body mass indexi> 35 kg/m2 were excluded.
he MOMS indings demonstrated improved early childhood outcomes in the prenatal surgery cohort (see Table 16-3). Children who had undergone prenatal surgery were twice as likely to walk independently by 30 months. hey had signiicantly less hindbrain herniation and were only half
Composite developmental scorea,b
TABLE 16-3. Benefits and Risks of Fetal 68% 98% <0.001 40% 82% <0.001 149 ± 58 123 ± 57 0.007 64% 96% <0.001 20% 48% <0.001 42% 21% 0.01 6% 0 0.03 6% 0 0.03 9% 1% 0.03 21% 4% 0.001 34 ± 3 37 ± 1 <0.001 79% 15% <0.001 aEach primary outcome had two components. The perinatal death components of the primary outcomes as well as the Bayley Mental Development Index at 30 months did not differ between the two study cohorts.
bScore derived from Bayley Mental Development Index and difference between functional and anatomical level of lesion (30 months).
Data from Adzick, 201s1s.
FIGURE 16-2 Fetal myelomeningocele surgery. A. With the edges of both the laparotomy and hysterotomy incisions retracted, the skin around the defect is incised. Subsequently, the neural placode is sharply dissected from the arachnoid membrane. B. The dural membrane is reflected to the midline to cover the neural placode and is reapproximated using suture. In some cases a patch is needed (not shown). The fetal skin incision is subsequently sutured. Last, hysterotomy and laparotomy are then closed. (Reproduced with permission from Shamshirsaz AA, Ramin, SM, Belfort MA: Fetal therapy. In Yeomans ER, Hoffman BL, Gilstrap LC III, et al: Cunningham and Gilstrap's Operative Obstetrics, 3rd ed. New York, McGraw-Hili Education, 201o7.) as likely to undergo ventriculoperitoneal shunting by the age of 1 year. A primary outcome was a composite score that was derived from the Bayley Mental Development Index and from the diference between the functional and anatomical level of the lesion at 30 months. This primary outcome was also signii cantly better in the prenatal surgery group.
When counseling prospective families, however, results are placed in perspective. For example, despite improvements in the proportion with independent ambulation, most children who received fetal surgery were not able to ambulate inde pendently, and nearly 30 percent were not able to ambulate at all. Prenatal surgery did not confer improvements in fetal or neonatal death rates or in the Bayley Mental Development