Chiari Malformation - Symptoms, Causes, & Treatment

By: Neda Brinster

Sharma, Rohit. “Chiari Malformations: Radiology Reference Article.” Radiopaedia Blog RSS, radiopaedia.org/articles/chiari-malformations.

Background - What is it?

Chiari Malformation is a rare congenital disorder that occurs when cerebellar tissue is pushed down into the spinal canal, through the foramen magnum. This is due to raised intracranial pressure, most likely caused by structural defects to the skull, specifically the hypoplastic occipital bone. The expansion of the cerebellum, or cerebellar tonsil herniation, disrupts the flow of cerebrospinal fluid, or CSF, throughout the brain, which can lead to the development of severe neurological symptoms.

Symptoms - Do I have it?

Depending on the neural structures that are compressed or crowded, neurological symptoms may vary. General symptoms for Chiari Malformation I include neck pain, dizziness, headaches, limited range of motion, or sleep apnea. Most patients with presenting symptoms will undergo decompression surgery to restore CSF flow.

Surgical Approach - How is it fixed?

The most common surgical approach is suboccipital craniectomy decompression, which includes numerous variations depending on compression severity. Craniotomy decompression removes a piece of the skull to stop compression and restore cerebrospinal fluid. At times, when CSF flow is not restored, a duraplasty will also be performed. A duraplasty is a procedure in which part of the dura, the covering of the brain, is removed. A pericranium or synthetic graft is then placed, which extends the dura to allow the brain to expand, reducing pressure. Another method is burning part of the cerebellar tonsils, which do not directly affect total functions of the brain. This will also allow for more space for CSF flow.

Complications - What can happen after?

Although many patients have a relief of symptoms, possible surgical complications may occur. Some of which include CSF leakage, meningitis, neurological deficits, neck pain, headaches, and more. Depending on the severity / invasiveness of the surgery, these complications will vary.

Learn more about Chiari Malformation with this video!

References:

“Chiari Malformation.” AANS, www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Chiari-Malformation#:~:text=Chiari%20malformation%20is%20the%20leading,flow%20at%20the%20foramen%20magnum. Accessed 13 Aug. 2023.

McClugage SG, Oakes WJ. The Chiari I malformation. J Neurosurg Pediatr. 2019 Sep 1;24(3):217-226. doi: 10.3171/2019.5.PEDS18382. PMID: 31473667.

Giannakaki V, Wildman J, Thejaswini K, Pexas G, Nissen J, Ross N, Mitchell P. Foramen Magnum Decompression for Chiari Malformation Type 1: Is There a Superior Surgical Technique? World Neurosurg. 2023 Feb;170:e784-e790. doi: 10.1016/j.wneu.2022.11.119. Epub 2022 Nov 29. PMID: 36455845