Establishing the Physiology of Syringomyelia

The purpose of this study is to establish the mechanism of development and progression of
syringomyelia. Although syringomyelia usually accompanies anatomic abnormalities at the
craniocervical junction, the pathophysiology that relates these anatomic abnormalities to
syringomyelia development and progression is controversial. We have been testing the
hypothesis that progression of syringomyelia associated with the Chiari I malformation is
produced by the cerebellar tonsils partially occluding the subarachnoid space at the foramen
magnum and acting as a piston on the partially enclosed spinal subarachnoid space, creating
enlarged cervical subarachnoid pressure waves which compress the spinal cord from without,
not from within, and propagate syrinx fluid caudally with each heartbeat, which leads to
syrinx progression. We are also testing the hypothesis that development of syringomyelia
results from increased transit of CSF through the spinal cord parenchyma and into the
syrinx. Patients are treated with posterior fossa craniectomy, upper cervical laminectomy,
and duroplasty. We evaluate cerebrospinal fluid flow and pressure, syrinx size, neurologic
function, and the rate of entrance of CSF into the syrinx before and after surgery. These
studies and the intraoperative evaluation of the movement of the cerebellar tonsils and the
walls of the syrinx are providing data which elucidate the hydrodynamic mechanism of
development and progression of syringomyelia.

The best treatment for this type of syringomyelia has not been established. Present surgical
treatment results in disease stabilization in many, but not all patients, although objective
improvement is less common. Delayed deterioration is not uncommon. Correlation of the
anatomic and physiologic measurements should provide data which indicate the mode of
development and progression of syringomyelia and which may have implications for the optimal
treatment of syringomyelia.

- INCLUSION CRITERIA:

To be eligible to participate in this research study, the subject must:

Be 18 years of age or older.

Have syringomyelia.

Have a lesion that narrows the space for spinal fluid at the base of the skull or neck.
Prior surgery for syringomyelia does not result in exclusion from the study if there is
radiographic evidence of a syrinx and there is evidence of neurological deterioration
related to the syrinx.

Be able to give informed consent.

EXCLUSION CRITERIA:

The subject will not be eligible to participate in this research study if the subject:

Is pregnant (because X-rays might injure a fetus).

Cannot have an MRI scan as determined by the radiologist.

Has a problem with bleeding that cannot be corrected.

Is unable to understand the risks of the testing and surgical therapy.

Has a blood test for HIV (the virus that causes AIDS) that is positive, because a positive
HIV test would increase the risk of infection from research testing.