The risks of this procedure are minimal. Theoretically, there is a risk of nerve damage to the larger spinal nerve where medial branch of the dorsal ramus originates. However, 3-step safety precautions are taken to avoid this and true nerve damage is quite rare. At one particular level, the C2-3 level, you may experience a patch of numbness at the base of your skull after the procedure. This is expected after a neurotomy of the third occipital nerve (TON).
It is not uncommon to experience increased localized neck pain for 1-2 weeks from the time of the procedure.
As with any injection procedure, there is a remote risk of bleeding or infection.