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.

Outcome of isolated fetal talipes: A systematic review and meta-analysis.

INTRODUCTION: The aim of this systematic review was to explore the outcome of fetuses with a prenatal diagnosis of isolated talipes. MATERIAL AND METHODS: Medline, Embase, Cinahl, and Clinicaltrials.gov databases were searched. The outcomes explored were: associated anomalies detected at follow-up ultrasound examination; fetal magnetic resonance imaging (MRI) and birth; chromosomal abnormalities detected with standard and chromosomal microarray analysis, intrauterine, neonatal, and perinatal death, and termination of pregnancy; rate of surgical and nonsurgical treatment; neurodevelopmental outcome; and false-positive rate of prenatal diagnosis. Meta-analyses of proportions were used to combine data. RESULTS: Twenty-five studies (1567 fetuses) were included. Associated anomalies were detected in 7.8% (95% CI 0.1%-29.3%) of cases at follow-up ultrasound, and in 4.0% (95% CI 0.1%-13.2%) of cases, fetal MRI identified anomalies not detected at ultrasound assessment. Similarly, 7.0% (95% CI 3.4%-11.7%) of cases labeled as isolated talipes on prenatal imaging were found to have associated anomalies at birth. Abnormal karyotype was present in 3.6% (95% CI 1.7%-6.2%) of fetuses, whereas no anomaly was found at chromosomal microarray analysis, although this outcome was reported by only 1 study. Intrauterine death occurred in 0.99% (95% CI 0.4%-1.9%) of fetuses, whereas the corresponding figures for neonatal death and termination of pregnancy were 1.5% (95% CI 0.6%-2.6%) and 2.2% (95% CI 1.2%-3.4%), respectively. Surgical management of anomalies after birth was found in 41.7% (95% CI 27.0%-57.2%) of fetuses with isolated talipes, and 54.8% (95% CI 31.5%-77.0%) had nonsurgical management of the anomalies after birth. Abnormal neurodevelopmental outcome was reported in 7.6% (95% CI 1.0%-19.4%) of children, although this analysis was affected by the small number of included cases and short time of follow up. CONCLUSIONS: Isolated talipes detected on prenatal ultrasound carries a generally good prognosis. The incidence of additional abnormalities detected on fetal MRI, aneuploidy, or neurodevelopmental disability is relatively low. However, longitudinal ultrasound assessment during pregnancy and a thorough postnatal evaluation are recommended to rule out associated anomalies that may significantly impact short- and long-term prognosis.