Suggested indications and contraindications for the C2 nerve block and RFA procedure
| Indications | Contraindications |
|---|---|
| Occipital neuralgia for >6 weeks | Coagulopathy (INR > 1.5, platelets <50) |
| Ipsilateral arthrosis of the lateral C1–C2 facet joint on CT and/or MR imaging with C1–C2 foraminal stenosis | Known vertebral artery variant crossing at C1–C2 along the needle trajectory |
| Lack of response to conservative management (medication and/or occipital nerve block) | Contrast allergya |
Note:—RFA indicates radiofrequency ablation; INR, international normalized ratio.
↵a Relative contraindication because preoperative noncontrast MRA may be performed.