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Chiari Malformation


Chiari malformation is a congenital anomaly that occurs in the head area where the brain and spinal cord meet. It is also called Arnold Chiari malformation. There are 4 types. The most common type 1 is seen, followed by type 2 chiari malformation. The incidence in the population is less than 1 in a thousand. Most of the cases do not have any complaints or findings. Chiari malformation is usually diagnosed incidentally by taking an MRI of that area.


  • Type I is the most common form of Chiari malformations. Usually it watches silently. Anatomy is disturbed in the skull base and upper spine region. The cerebellum hangs down from the base of the skull. This downward shift obstructs the CSF circulation between the spinal cord and the intracranial. In this way, it may cause fluid accumulation in the spinal cord called syringomyelia or hydromyelia. Skull base developmental anomaly may accompany in 30 to 50% of Chiari type 1 cases. (Klippel-Feil deformity, spina-bifida okkulta, scoliosis-hydromyelia)

  • Type II Chiari malformation may be associated with Hydrocephalus. Hydrocephalus is a condition caused by an overproduction or malabsorption of the cerebrospinal fluid (CSF) that fills the chambers in the brain. The increased fluid increases the pressure in the head and expands towards the skull bones, causing a wider view than normal.




If the cerebrospinal fluid (CSF) creates a cavity in the spinal cord, it is called syringomyelia or hydromyelia. When the cavity starts to widen, it stretches the nerve fibers and starts to damage it. After a certain period of time, complaints and findings occur. It is thought to occur after the cerebellum blocks the passage of the CSF.

Hydromyelia can be defined as the abnormal enlargement of the central canal in the spinal cord.


Symptoms in Chiari Malformation


  • Headache.

  • Neck pain

  • Feeding and swallowing difficulties.

  • Loss of strength in the arms.

  • Loss of sensation in the arms and legs.

  • Loss of balance

  • Abnormal eye movements.

  • Growth retardation.

  • Weak cry.

  • Respiratory problems

  • Sleep apnea



Diagnosis of Chiari Malformation


Computed Tomography (CT): It consists of images obtained by shaping the data obtained using X-rays on a computer. It shows the inside of the skull and bone structures well.
Magnetic Resonance Imaging (MRI): It is the best diagnostic imaging method. Information about the brain, cerebellum, brainstem, spinal cord can be viewed. In these structures, MRI is preferred over CT.
Somatosensory evoked responses (SSEP): It is an electrical test that provides information about the function by controlling the passage of the stimulus through the cerebrospinal cord and nerves.

A typical case of Chiari Malformation is seen in the MR image below.


Chiari Malformation Treatment


The patient is evaluated with signs and symptoms. Asymptomatic patients are routinely followed up at regular intervals. If symptoms begin, the treatment of chiari malformation is surgery. One of the basic operations is to relieve the area where the base of the cerebellum compresses the brainstem and spinal cord. This relief is provided by removing a small part of the skull base bone, which is located deep in the neck muscles, mostly with the spine part along with it (Posterior fossa decompression surgery).

Dr. Tamer Tekin

Chiari Malformasyonu Tedavisi
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