Open Fetal Surgical Outcomes for Myelomeningocele Closure Stratified by Maternal Body Mass Index in a Large Single-Center Cohort

BACKGROUND

Open maternal-fetal surgery for in utero closure of myelomeningocele (MMC) has become an accepted treatment option for prenatally diagnosed open neural tube defects. Historically, this option has been limited to women with BMI < 35 due to concern for increasing complications in patients with obesity.

OBJECTIVE

The aim of this study was to evaluate maternal, obstetric, and fetal/neonatal outcomes stratified by maternal BMI classification in women who undergo open maternal-fetal surgery for fetal myelomeningocele (fMMC) closure.

METHODS

A single-center fMMC closure registry was queried for maternal demographics, preoperative factors, fetal surgery outcomes, delivery outcomes, and neonatal outcomes. Data were stratified based on maternal BMI: <30, 30-34.99, and ≥35-40, corresponding to normal weight/overweight, obesity class I, and obesity class II. Statistical analysis was performed using statistical software SAS v.9.4 (SAS Institute Inc., Cary, NC, USA).

RESULTS

A total of 264 patients were analyzed, including 196 (74.2%) with BMI <30, 54 (20.5%) with BMI 30-34.99, and 14 (5.3%) with BMI ≥ 35-40. Maternal demographics and preoperative characteristics were similar among the groups. Operative time increased with increasing BMI; otherwise, perioperative outcomes were similar among the groups. Obstetric and neonatal outcomes were similar among the groups.

CONCLUSION

Increasing maternal BMI did not result in a negative impact on maternal, obstetric, and fetal/neonatal outcomes in a large cohort of patients undergoing open maternal-fetal surgery for fMMC closure. Further study is warranted to determine the generalizability of these results.

Myelomeningocele sac associated with worse lower-extremity neurological sequelae: evidence for prenatal neural stretch injury?

OBJECTIVE

To determine whether the presence of a myelomeningocele (MMC) sac and sac size correlate with compromised lower-extremity function in fetuses with open spinal dysraphism.

METHODS

A radiology database search was performed to identify cases of MMC and myeloschisis (MS) diagnosed prenatally in a single center from 2013 to 2017. All cases were evaluated between 18 and 25 weeks. Ultrasound reports were reviewed for talipes and impaired lower-extremity motion. In MMC cases, sac volume was calculated from ultrasound measurements. Magnetic resonance imaging reports were reviewed for hindbrain herniation. The association of presence of a MMC sac and sac size with talipes and impaired lower-extremity motion was assessed. Post-hoc analysis of data from the multicenter Management of Myelomeningocele Study (MOMS) randomized controlled trial was performed to confirm the study findings.

RESULTS

In total, 283 MMC and 121 MS cases were identified. MMC was associated with a lower incidence of hindbrain herniation than was MS (80.9% vs 100%; P < 0.001). Compared with MS cases, MMC cases with hindbrain herniation had a higher rate of talipes (28.4% vs 16.5%, P = 0.02) and of talipes or lower-extremity impairment (34.9% vs 19.0%, P = 0.002). Although there was a higher rate of impaired lower-extremity motion alone in MMC cases with hindbrain herniation than in MS cases, the difference was not statistically significant (6.6% vs 2.5%; P = 0.13). Among MMC cases with hindbrain herniation, mean sac volume was higher in those associated with talipes compared with those without talipes (4.7 ± 4.2 vs 3.0 ± 2.6 mL; P = 0.002). Review of the MOMS data demonstrated similar findings; cases with a sac on baseline imaging had a higher incidence of talipes than did those without a sac (28.2% vs 7.5%; P = 0.007).

CONCLUSIONS

In fetuses with open spinal dysraphism, the presence of a MMC sac was associated with fetal talipes, and this effect was correlated with sac size. The presence of a larger sac in fetuses with open spinal dysraphism may result in additional injury through mechanical stretching of the nerves, suggesting another acquired mechanism of injury to the exposed spinal tissue. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Subsequent pregnancy outcomes after open maternal-fetal surgery for myelomeningocele

BACKGROUND

Open maternal-fetal surgery for fetal myelomeningocele results in reduction in neonatal morbidity related to spina bifida but may be associated with fetal, neonatal, and maternal complications in subsequent pregnancies.

OBJECTIVE

The objective of this study was to ascertain obstetric risk in subsequent pregnancies after open maternal-fetal surgery for fetal myelomeningocele closure.

STUDY DESIGN

An international multicenter prospective observational registry created to track and report maternal, obstetric, fetal/neonatal, and subsequent pregnancy outcomes following open maternal-fetal surgery for fetal myelomeningocele was evaluated for subsequent pregnancy outcome variables. Institutional Review Board approval was obtained for the registry.

RESULTS

From 693 cases of open maternal-fetal surgery for fetal myelomeningocele closure entered into the registry, 77 subsequent pregnancies in 60 women were identified. The overall live birth rate was 96.2%, with 52 pregnancies delivering beyond 20 weeks gestational age and median gestational age at delivery of 37 (36.3-37.1) weeks. The uterine rupture rate was 9.6% (n = 5), resulting in 2 fetal deaths. Maternal transfusion was required in 4 patients (7.7%).

CONCLUSION

The risk of uterine rupture or dehiscence in subsequent pregnancies with associated fetal morbidity after open maternal-fetal surgery is significant, but is similar to that reported for subsequent pregnancies after classical cesarean deliveries. Future pregnancy considerations should be included in initial counseling for women contemplating open maternal-fetal surgery.