Arnold-Chiari malformation
Pronunciation: AR-nold kee-AH-ree
Hindbrain herniation commonly associated with spina bifida requiring neurosurgical evaluation.
Full Definition
Arnold-Chiari malformation, specifically Type II, involves herniation of the cerebellar vermis and brainstem through the foramen magnum into the cervical spinal canal. This condition is present in virtually all cases of open spina bifida and contributes to hydrocephalus development. The malformation affects cerebrospinal fluid flow and can cause brainstem compression, leading to respiratory and swallowing difficulties. Prenatal repair of spina bifida has been shown to reverse some features of the Chiari malformation, reducing the need for postnatal shunting.
Usage
Usage note: Distinguish between Type I (adult-onset) and Type II (associated with spina bifida) when editing clinical documentation.
In Context
- "The Arnold-Chiari malformation showed significant improvement on postnatal imaging following prenatal repair." — Follow-up surgical report
- "Severe Arnold-Chiari malformation may contraindicate fetal surgery due to poor prognosis." — Multidisciplinary team discussion notes