Central nervous system findings on fetal magnetic resonance imaging and outcomes in children with spina bifida.

OBJECTIVE: To estimate the relationship between fetal magnetic resonance imaging (MRI) findings of ventriculomegaly, cerebellar herniation, extraaxial space effacement and adverse outcomes in children with spina bifida. METHODS: This was a review of all pregnancies with spina bifida referred for fetal MRI from 2001 to 2007 and cared for postnatally at our spina bifida referral center. Degree of cerebellar herniation was based on lowest cervical vertebral level reached. Extraaxial space was considered effaced if too small to be measured above or below the tentorium cerebelli. Bladder dysfunction was termed high risk if renal damage was present or urodynamic studies indicated increased risk for renal damage. Ambulation was assessed in children age 3 years or older. Statistical analyses included chi square, Mantel-Haenszel test, and logistic regression. RESULTS: Magnetic resonance imaging was performed in 36 pregnancies with fetal spina bifida at 276 weeks with subsequent delivery at 381 weeks. Outcomes were assessed at 3.2 years (range 2.4–5.1); 23 children were age 3 years or older. If the cerebellum was above the foramen magnum or had herniated to C2, C3, or C4, respectively, childhood seizures occurred in 0%, 7%, 21%, and 100%; high-risk bladder dysfunction in 33%, 33%, 71%, and 100%; and inability to ambulate independently in 20%, 70%, and 100% (no C4 cases) all P<.05. Ventriculomegaly, cerebellar herniation, and extraaxial space effacement were significantly associated with the need for ventriculoperitoneal shunt; however, 94% of children required shunt placement. CONCLUSION: In fetuses with spina bifida, worsening cerebellar herniation on MRI was significantly associated with childhood seizure activity, high-risk bladder dysfunction, and lack of independent ambulation.