Chiari III Malformation: Quantification of Long-term Outcome After Early Surgery.

Chiari malformation type III is a rare and severe congenital disorder characterized by herniation of posterior fossa contents into a posterior encephalocele and by other abnormalities. It is associated with a high rate of early mortality and survivors suffer from neurologic deficits and mental retardation. There is only very limited data available on long-term outcome after surgery, and in general there is a lack of quantification of disability. In this technical note, we present the case of a female newborn diagnosed already during pregnancy with a Chiari malformation type III. Surgical management and a proposal for comparable standardized test battery for long-term outcome was presented. A caesarean section was performed at 37 + 1 weeks of gestation, followed by surgical repair of the meningoencephalocele and placement of a ventriculoperitoneal shunt. Despite an uncomplicated postoperative course, development was markedly delayed. At the last follow-up at 40 months, the patient exhibited severe deficits, including a total IQ of 65 (below the 1st percentile), along with significant impairments in memory and metacognitive development, as assessed by the Behavior Rating Inventory of Executive Function. The prenatal diagnosis of Chiari malformation type III is a challenge both with regard to parent counseling and treatment decisions. It is necessary to document the postoperative development of these patients with various degrees of disability according to standardized tests on long-term follow-up to gain more insight for future decision-making.