Cervical spine surgeries do always have risks.
Especially in the area of the cranio-cervical junction there are structures which are very important for vital functions. Surgeries close to this area are particularly risky.
Every neurosurgeon has his own technique and material he likes the most. Every technique has advantages and disadvantages which have to be included in your decision.
It is very important to be informed about possible risks. Ask the surgeon as many questions as you have. It should be a very knowledgeable and experienced surgeon in case of cranio-cervical fusion.
A surgery must ALWAYS be the last resort after all non-invasive treatments have been tried without success.
Minimal invasive methods do often have lower risks. The incision is usually smaller, less structures are damaged and healing afterwards is easier.