Not everyone with a Chiari malformation requires surgery, but when a patient's individual circumstances warrant it, a neurosurgeon may recommend "decompression" surgery (known as a “decompressive suboccipital craniectomy and cervical laminectomy”). As its name suggests, the goal of this procedure is to reduce or eliminate the pressure on the spinal cord caused by the cerebellar tonsils. Nearly all patients who undergo decompression surgery enjoy partial or total improvement in their symptoms, with very little risk.
In decompression surgery, which is performed under general anesthesia, a neurosurgeon makes an incision in the back of the head and removes a small piece of the skull. After this first part of the surgery, the neurosurgeon will evaluate whether or not enough pressure has been relieved. If further decompression is necessary, surgery continues in a second step that involves opening the dura (duraplasty, durotomy), the tissue that covers and protects the brain and spinal cord. Opening the dura results in a more immediate and thorough reduction of pressure on the spinal cord. (See Pictures of Chiari.)
The decision to open the dura is made based upon a number of factors, including the patient's symptoms, the age, the presence or absence of syringomyelia, and the operative findings sometimes including the use of real-time Doppler ultrasonography. Traditional surgery with dural opening can take approximately three-four hours compared with the dural-sparing minimally invasive endoscopic surgery, which can take as little as two hours. The hospital stay for decompression surgery can be from one to five days, depending on the procedure used. At home recovery from Chiari surgery can take up to two or three weeks, during which the patient should restrict strenuous activity. Once the patient has recovered, he or she can generally resume normal activity. The neurosurgeon will make specific recommendations about ongoing activities, including contact sports. The good news is that the vast majority of Chiari patients can safely return to all their pre-operative activities. (See We Conquered Chiari: Patients and Parents Share Their Stories)
Patients who have had decompression surgery for Chiari should visit their neurosurgeon a few months after the procedure for an MRI to confirm that the pressure has been alleviated. Subsequent imaging will depend on the patient's symptoms and the results of the previous MRI. Patients rarely need additional procedures, but a neurosurgeon should monitor them for any signs of complications or a return of symptoms. The youngest patients – those under 3 years of age – have the greatest likelihood (approximately 15 percent) of repeat surgery due to their ability to have bone regrowth.
Weill Cornell Medicine conducts clinical trials for patients with Chiari malformation; please ask your physician about these studies and if you may be eligible.
Reviewed by Jeffrey Greenfield, Ph.D., M.D.
Last reviewed/last updated: April 2021