Background: Fourth ventricle (FV) dilatation is increasingly diagnosed in premature infants with posthemorrhagic hydrocephalus (PHH) following ventriculoperitoneal shunt (VPS) insertion. Information is limited, however, on its incidence, imaging, risk factors and long term clinical manifestations.
Objective: To determine the incidence of FV dilatation in preterm infants with PHH following VPS, describe its MRI features, identify neonatal and neurosurgical risk factors, and determine neuro-developmental outcome.
Methods: We retrospectively evaluated 31 infants, who developed PHH and required a VPS insertion. On follow-up MRI (age >2 years), we measured the diameter and / or area of the FV, pons, medulla, and cerebellar hemispheres. We then performed neuromotor and developmental evaluation (Battelle Developmental Inventory II).
Results: A moderate to severe FV dilatation (area >70mm2) was found in 19 (61%) infants. Mean FV area was larger in infants who manifested neurosurgical complications in comparison to those without (674.4±817 mm2 v.s. 193.1±178.7 mm2,P=0.03). Mean FV area was significantly correlated to total developmental score (r=-0.4, p=0.014(, and cognitive sub scores (r=-0.4, p=0.035), but not to motor sub scores. Pons diameter and the cerebellar area were significantly correlated to total developmental score (pons: r=0.6, p= <0.001, cerebellum: r=0.5, p=0.005(, cognitive sub score (pons: r=0.6, p=0.001, cerebellum: r=0.4, p=0.015), and motor sub score (pons: r=0.6, p=0.01, cerebellum: r=0.4, p=0.02).
Conclusions: FV dilatation is relatively common in infants with PHH following VPS insertion. It is accompanied by reduction in cerebellar and brainstem dimensions and correlates with poor neurodevelopmental outcome. The value of FV drainage should be assessed in future prospective trials.
