Chiari malformation

Chiari malformation

Anesthetic relevance	Moderate
Anesthetic management	Avoid increased ICP
Specialty	Neurology
Signs and symptoms
Diagnosis
Treatment	Surgical decompression
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A Chiari malformation is an elongated cerebellar vermis that herniates through the foramen magnum, compressing the brain stem. Chiari malformations are classified as Type I-IV based upon on the extent of herniation.

Anesthetic implications

Intraoperative management

• Avoid increased ICP

Related surgical procedures

• Craniocervical decompression

Pathophysiology

• Type I: Only the cerebellar tonsils extend into the foramen magnum
  • Most common, may be asymptomatic
• Type II: Cerebellar tonsils and brainstem tissue extend into foramen magnum
  • Also known as an Arnold-Chiari malformation
  • Associated with myelomeningocele
• Type III: Herniation of cerebellum, brain stem and possibly the fourth ventricle through the foramen magnum
• Type IV: Cerebellar hypoplasia
  • Typically does not survive past infancy

Signs and symptoms

• Headache (especially after valsalva)
• Neck Pain
• Balance problems
• Weakness
• Decreased sensation

Common pediatric presentations include:

• Dysphagia
• Recurrent aspiration
• Stridor
• Apneic episodes
• Lack of gag reflex
• Often associated with syringomyelia and therefore arm weakness and sensory deficits

Diagnosis

• MRI

Treatment

Surgery

• Chiari malformations can be surgically treated with a craniocervical decompression

• Type I Chiari malformations may be asymptomatic and not require treatment
• The timing of surgery depends on the severity of the malformation and associated symptoms

Prognosis

• Variable depending on the severity of the malformation and the success of surgery