Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency care for severe breathing difficulty, ongoing choking, sudden major weakness, loss of consciousness, or sudden neurological symptoms such as facial drooping or difficulty speaking.
Contact the treating team promptly for worsening weakness, repeated falls, increasing numbness, new swallowing problems, drainage or swelling at a surgical incision, fever after surgery, or a major change in bladder or bowel control.
Follow-up is based on symptoms, age, examination findings, and whether a syrinx or another associated condition is present.
Care may involve primary care, neurology, neurosurgery, rehabilitation, sleep medicine, or other specialists.
At routine visits, discuss changes in headaches, balance, swallowing, sleep, strength, sensation, hand function, and bladder or bowel control.
Children may also need monitoring for scoliosis, growth, school difficulties, and changes in motor development.
Routine headaches or stable long-term symptoms can usually be discussed at a scheduled visit unless their pattern changes significantly.
The article also says
After surgery, follow the care team’s instructions about wound care, activity, return to work or school, and imaging.
Recovery time varies.
Improvement may be gradual, and some symptoms may remain even when cerebrospinal fluid flow has improved.
Every sign above is quoted from the sofidex article on Arnold-chiari malformation. If you are not sure, err upward — it is always reasonable to be checked.