Outcomes of Postnatal Myelomeningocele Repair in a Japanese Single-center Cohort: A Comparison with the Management of Myelomeningocele Study Trial

Fetal surgery for myelomeningocele is not yet standard practice in Japan. To establish baseline data for the outcomes of standard postnatal care for patients eligible for fetal surgery, we compared the results from our large, single-institution cohort with those of the Management of Myelomeningocele Study trial's postnatal group. We retrospectively reviewed 65 patients who underwent postnatal myelomeningocele repair at our center between 2002 and 2021. In our cohort, the myelomeningocele lesion level was thoracic in 18% of patients, L1-L2 in 12%, and L3 or below in 69%. Key outcomes, including the rate of cerebrospinal fluid shunt placement at 12 months and ambulation status at 30 months, were compared to the published data from the Management of Myelomeningocele Study postnatal cohort. The rate of cerebrospinal fluid shunt placement in our cohort (88%) and ambulation rates at 30 months (28%) showed no statistically significant difference from the Management of Myelomeningocele Study postnatal group (83%, p = 0.39, and 20%, p = 0.29, respectively). Our cohort had a significantly lower rate of shunt infection (0% vs. 9%, p = 0.02). However, the rates of surgery for symptomatic Chiari II malformation (18% vs. 5%, p = 0.01) and for tethered cord syndrome (9% vs. 1%, p = 0.03) were significantly higher in our cohort. The outcomes of modern postnatal myelomeningocele repair at a major Japanese center are largely consistent with the international benchmark set by the Management of Myelomeningocele Study trial. This study provides an essential baseline of data that will be indispensable for counseling families and for the objective evaluation of fetal surgery as it is introduced in Japan.