Fetal hydrocephalus

Abstract

Fetal hydrocephalus is a dynamic process. Its natural progression is not completely understood, but it is almost always associated with other intracranial and extracranial anomalies. Fetal hydrocephalus might begin as mild ventriculomegaly and progress to a more serious state. Mild ventricular enlargement without an increase in head size might be a normal variant. Careful prenatal evaluation is always indicated when the diagnosis of ventricular enlargement has been made, and it should include a detailed anatomic survey and genetic amniocentesis. Therapeutic options need to be discussed in detail with the patient. If multiple associated anomalies--especially other CNS anomalies--are present, the prognosis for a viable outcome is dismal. If isolated hydrocephalus is seen, gender determination is appropriate in the consideration of X-linked hydrocephalus secondary to aqueductal stenosis. Communicating hydrocephalus can also be mistaken for obstructive ventriculomegaly, but it can usually be excluded by demonstration of dilation of the subarachnoid cistern. There is a small subset of fetuses that have isolated hydrocephalus that might benefit from prenatal surgical intervention. Feasibility studies are in progress to assess the therapeutic benefit of this type of therapy. Gestational age requirements and strict criteria are being evaluated. As with the multiple therapies discussed in this issue, many interventions are becoming more and more feasible, and antenatal surgery is likely to be limited only by the ability to think imaginatively and to act creatively.

A Prospective Study of Fetuses with Isolated Ventriculomegaly Investigated by Antenatal Sonography and In Utero MR Imaging

“…It is widely accepted that severe categories of VM are associated with higher risks of poor clinical outcome, 12 and indeed recent studies have questioned whether mild VM (trigone measurements of 10 -12 mm) is truly abnormal if it is an isolated finding. 13,14 For example, in a study of 176 cases, Gaglioti et al 7 showed that a fetus with isolated VM had a 97.7% chance of being alive at 2 years if the VM was mild, an 80% chance with moderate VM, and a 33.3% chance with severe VM. Of those that were alive, neurodevelopmental outcome was normal in 93% of mild cases, 75% of moderate, and 62.5% of severe VM cases.…”

Fetal Therapy for Isolated Aqueductal Stenosis

“…Placed by ultrasound guidance similar to vesicoamniotic or thoracoamniotic shunts (thereby avoiding the maternal morbidity associated with laparotomy and hysterotomy), they had a tendency to obstruct and to migrate [7]. A single published series of patients who underwent ventriculoamniotic shunt placement by hysterotomy documented a lower shunt failure rate [29]. However, the need for hysterotomy negatively impacts upon the overall risk-benefit assessment.…”

Management of Hydrocephalus

“…Most experts define fetal ventriculomegaly as a lateral ventricular atrial measurement of greater than 15mm.Ventriculomegaly is "isolated" when the fetus has no other anomalies (15)(16). The prevalence of ventriculomegaly is less than 2 percent, but reports vary widely within that range (17).…”