NICHD Study Update: Does Prenatal Surgery of Myelomeningocele Improve Motor Development Beyond 2 Years Follow-Up?

BACKGROUND AND PURPOSE: 

• The initial report of the NICHD prenatal myelomeningocele study demonstrated improvement in the following   
  • Decreased hindbrain herniation and consequent need for shunting and improved distal neurologic function 
• Long-term outcomes have confirmed shunting benefit but data on neurologic and motor function outcomes were lacking  
• Farmer et al. (Am J Obstet Gynecol., 2018) report the 30-month outcomes for the entire cohort of patients randomized to either prenatal or postnatal repair of myelomeningocele 

METHODS: 

• Follow-up analyses of NICHD sponsored Management of Myelomeningocele Study 
• Women had been randomly assigned to undergo 
  • Standard postnatal repair 
  • Prenatal repair at <26 weeks gestation 
• Primary outcome of the study was a composite of mental development and motor function outcome at 30 days  
• Secondary outcomes 
  • Independent ambulation and the Bayley Sales of Infant Development (2nd edition) 
• Effects and Subgroups
  • Fetal leg movements 
  • Ventricle size 
  • Presence of hindbrain herniation 
  • Gender  
  • Location of the myelomeningocele lesion 
• Within the prenatal surgery group only, these and other baseline parameters were evaluated as predictors of 30-month motor and cognitive outcomes 
• Researchers also assessed if the presence or absence of a shunt at 1 year was associated with 30-month motor outcomes 

RESULTS: 

• Data from 183 subjects were analyzed  
• Prenatal repair improved the primary outcome  
  • Composite score of mental development and motor function was 199.4 ± 80.5 vs 166.7 ± 76.7 (P=.004) 
• Prenatal surgery resulted in improvements in the secondary outcomes of 
  • Independent ambulation (44.8% vs 23.9%, P=.004) 
  • Self-care score (20.8 vs 19.0, P=.006) 
  • Mean Bayley Scales of Infant Development, psychomotor development index (17.3% vs 15.1%, P=.03) 
• Prenatal surgery did not affect cognitive development at 30 months 
• Boys demonstrated slightly better improvement in functional level and psychomotor development index 
• Independent ambulation was associated with 
  • Patients receiving prenatal surgery 
  • The presence of in utero ankle, knee, and hip movement 
  • Absence of a sac over the lesion and a myelomeningocele lesion ≤L3  
• Postnatal motor function showed no correlation with either prenatal ventricular size or postnatal shunt placement 

CONCLUSION: 

• The full cohort data of 30-month cognitive development and motor function supported previous findings 
• Prenatal surgery of myelomeningocele improved motor function, mental development, independent ambulation, self care score 
• Indicators of independent ambulation were identified including presence of in utero joint movement and absence of sac over the lesion and a lesion ≤L3.  
• Future research should focus on longer-term follow up to school age  
• This study did not use fetoscopic methods, which also awaits further research  
  • Primary benefit of fetoscopy would be to avoid requirement for cesarean section

Learn More – Primary Sources: 

The Management of Myelomeningocele Study: full cohort 30-month pediatric outcomes.