S is for Syringomyelia This condition is the most common issue associated with Chiari. Do you have Syringomyelia? How long? This is a condition where fluid-filled cysts (syrinx) form in the spinal cord. They can also form in the brainstem (syringobulbia). Syringomyelia is rare with 8.4 in 100,000 people having it. Chiari is the most common cause, but it can also be post-traumatic, from other conditions like tethered cord, rumour or idiopathic (unknown origin).