Pathophysiology of isolated lateral ventriculomegaly in shunted myelodysplastic children.

Eight myelodysplastic children developed isolated lateral ventriculomegaly following shunt insertion for progressive hydrocephalus after closure of a myelomeningocele. In all patients a low-pressure distal slit valve (Uni-shunt) system preceded development of an isolated contralateral ventricle. Six of 8 children required a second contralateral shunt for a symptomatic isolated ventricle. Magnetic resonance imaging demonstrated a collapsed ventricle ipsilateral to the shunt secondary to distortion of the foramen of Monro. This was clearly depicted using three-dimensional color reconstructions of the ventricular anatomy. Low-pressure distal slit valves should be avoided in myelodysplastic children to prevent postshunt ventricle isolation.