All surgeries, even the most minor, carry a risk of complications. Spinal surgery has these risks and a few others because of the location and the complexity of the surgeries.
The usual types of complications are infections, blood clots in the legs, pneumonia, and bleeding. But, because it’s spinal surgery, there is also the possibility of nerve damage from either the surgery itself, the instruments, bleeding during surgery, or several other factors. The best thing would be to discuss the possible complications and see what your mother’s doctor says about the different risks.