Introduction: In spina bifida aperta (SBA), fetal myelomeningocele (MMC) closure can reduce shunt dependency and preserve segmental neuro-muscular function. Fetal MMC closure is performed by open and fetoscopic techniques. Comparative neuromuscular outcome data are incomplete. Muscle ultrasound density parameters (dMUD) can non-invasively quantify muscle damage by the MMC. We compared neuormuscular outcome parameters between fetal-open, fetoscopic and postnatal MMC surgery.
Methods: We investigated 30 age- and lesion-matched pairs: I. 17 matched-pairs of fetal open (Katowice, Poland) versus neonatal (Groningen, Netherlands) operations [median age 2 years; MMC L4] and II. 13 matched-pairs of fetoscopic (Bonn, Germany) versus neonatal (Groningen, Netherlands) operations [median age 1 year; MMC L3]. dMUD=[MUDcaudal-to-MMC(calf)] minus [MUDcranial-to-MMC(biceps/quadriceps)].1
Results: Neuromuscular segmental difference between I. fetal-open vs postnatal operation, respectively: median +1 dermatome (range -2-5) for sensory function; p=0.02. Motor function and dMUD: 25 (-10-71) vs 18 (-13-61), NS. Shunt-dependency: 4/17 vs 14/17; p<0.05. II. fetoscopic vs postnatal operation: +2 myotomes (range -0.5-4) and +2 dermatomes (range -1.5-5); dMUD: 15 (-9-68) vs 26 (5-39), shunt-dependency: 4/13 vs 12/13, all p<0.05.1 Fetoscopic operation seemed associated with more segmental neuroprotection (sensory and motor function) than fetal-open operation: +2 (-1.5-5) vs +0.25 (-2.5-6) segments, respectively, p=0.04.
Conclusion/Discussion: In SBA, open fetal and fetoscopic MMC closure techniques are both associated with neuro-protection (compared with postnatal MMC closure), with potentially the strongest effect in the fetoscopic group. Before clinical implementation, these data should be carefully interpreted against the risk of complications in mother and child.

Reference:
1. Verbeek RJ et al. Dev Med Child Neurol 2012;54:15-22.