Posterior fossa decompression for Chiari malformation

Chiari malformation is a condition in which brain tissue extends into the spinal canal. Occurring when part of the skull is small or misshapen, it forces the brain downward; Chiari malformation may be congenital, it may develop over time, or it may be the result of trauma to the skull.

Though there is no cure for Chiari malformation, treatment through surgery has proven to be an effective means of managing the symptoms. A posterior fossa decompression is the surgical procedure performed to remove the bone at the back of the skull and spine. The dura overlying the tonsils is opened and a patch is sewn to expand the space, similar to letting out the waistband on a pair of pants. The goals of surgery are to stop or control the progression of symptoms caused by tonsillar herniation, to relieve compression of the brainstem and spinal cord, and to restore the normal flow of cerebrospinal fluid (CSF). The surgery takes about 2 to 3 hours and recovery in the hospital usually lasts 2 to 4 days.

After surgery, you can expect headache and neck pain from the incision that may last several weeks. You will gradually be able to do more of your everyday activities as you heal and recover, but initially you should not lift anything more than five pounds and should rest as much as possible. Full recovery may take four to six weeks, depending on your general health.

The results of your decompression surgery depend on the severity of the Chiari malformation and the extent of any previous brain and nerve injury before treatment. Exertional headache and neck pain respond well to decompressive surgery as do most of the brainstem signs (e.g., swallowing problems, facial pain/numbness, voice changes, tinnitus, eye problems, dizziness). Recovery of sleep problems, memory, and spinal cord signs (e.g., numbness or tingling in hands and feet, muscle weakness) take longer and may not completely return to normal. Risk of increasing head and neck pain is minimal.