What is the link between chiari malformation and syringomyelia?

Sometimes: Sometimes both are present. Look for other when one is found.

CSF dynamics: Chiari may alter the flow of cerebrospinal fluid at the cervico-cranial junction and may cause fluid pulsations and widening of the central canal. Theories abound but no definite mechanism has been confirmed. Usually the chiari and syrinx are diagnosed together so it is hard to tell if they are congenital, or if the chiari is causative.

Chiari: Additionally, though i sometimes recommend observation with some chiari patients, those with syringomyelia i offer surgical decompression.