This herniation can, and often does
, get worse. If you are diagnosed with Chiari 1, you generally will be told how
far the herniation extends in millimeters. At around 8 mm, doctors start considering surgery. This isn't a set number and can be more or less, often the decision is made because of possibe damage to the spine - syringomyelia ( a blockage of spinal fluid that can lead to paralysis) is often (almost always) eventually assoiciated with Chiari.