Hi, I have gone through your question and understand your concerns. Arnold-Chiari malformation if symptomatic, is treated by surgery. Surgery consists on decompression of posterior fossa, i.e. removing a part of bone in your back part of your head, cutting and releasing outer and, in certain cases, middle coverings of the brain ( dura and arachnoid), putting a graft on it, relieving in this manner cerebellum ( small brain) and brainstem. It is a brain surgery and these types of operations carry risks also. Risks include cerebrospinal fluid leakage, wound infection, recurring of Arnold-Chiari malformation, rarely brain structures damage. Hope this answers your question. If you have additional questions or follow up questions then please do not hesitate in writing to us. I will be happy to answer your questions.