Myelomeningocele: the management of the associated hydrocephalus

The pathogenesis of the hydrocephalus associated with myelomeningocele (MMC) has been the subject of an extensive number of studies. The contemporary reduction of the incidence of the Chiari II malformation and of the associated active hydrocephalus after closure of the spinal defect in utero is in line with previous studies suggesting a prominent role of the posterior cranial fossa abnormalities, where even the increased venous pressure might be at least mostly a consequence of the constriction of the posterior cranial fossa structures. Pure absorptive abnormalities however coexist, the main ones documented to be abnormal cisternal spaces and peculiar cerebrospinal fluid chemical features.

We reviewed the pertinent literature concerning the pathogenesis and management of the hydrocephalus associated to MMC. We also reviewed our personal experience in managing the hydrocephalus in such patients through an endoscopic third ventriculostomy.

The literature review demonstrated an overall reduction in more recent series of children with MMC needing to be treated for the associated hydrocephalus postnatally, questioning the role of the prenatal care of the disease in this context. Less severe conditions and a more conservative neurosurgical attitude have certainly contributed to the reduction of the reported active postnatal hydrocephalus rate. Long-term cognitive evaluation of the children with MMC that we managed with an endoscopic third ventriculocisternostomy (ETV) as primary as well as secondary procedure did not demonstrate significant differences in the outcome compared with non-complicated extrathecally shunted children, favouring ETV as a valuable option in this subset of patients.