Not everyone with Chiari Malformation requires surgery, but when a patient's individual circumstances warrant it, we recommend decompression surgery – clinically known as a decompressive suboccipital craniectomy and cervical laminectomy.
The goal of the procedure is to significantly reduce or eliminate pressure on the spinal cord caused by pressure from the cerebellar tonsils. Nearly all patients who undergo decompression surgery enjoy partial or total improvement in their symptoms with negligible risk.
During decompression surgery, the neurosurgeon makes an incision in the back of the head and removes a small piece of the skull. Most of the decompressive effect on the brainstem occurs after the bone removal. But in some cases, it is not enough.
If the determination is made that further decompression is necessary, an additional step involving opening the dura (short for dura mater) may be done. The dura is the thick lining that surrounds the brain and spinal cord creating a closed system. Spinal fluid inside this system regulates pressure and helps to cushion these structures.
The decision is based on a number of other factors, including the patient's symptoms, their age and the presence or absence of syringomyelia. The decision is an important one because temporarily opening the dura increases the possibility, however small, of contamination.
For many years, it was a standard procedure for surgeons to open the dura lining to further relieve pressure. And for many surgeons, this is still the case.
There is no universal “best practice” agreed to by neurosurgeons regarding the decision to open or not open the dura. “In cases involving syringomyelia or severe Chiari malformation our tendency is to open the dura,” Dr. Krumerman explained.
Dr. Jackson summarized the DNS philosophy, “Our considerable experience in performing chiari malformation surgery over many years has shown us that this decision is best made on a case-by-case basis – often during surgery when we can see exactly what’s going on.”