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How would you code the following? It has been suggested to use codes 64640 and 77013, as these are not true paravertebral facet joints. Looking for clarification or suggestions. "The region of the medial branches at the L5/S1, S1, S2, and S3 levels were identified under CT. The overlying skin was then numbed using 1% lidocaine. Under CT guidance needles were advanced adjacent to these nerve sites. The ablation needles were placed, and motor testing was performed at four sites. No motor activity was appreciated. The sites were then numbed with Marcaine, and ablation of the L5/S1 facet as well as the S1-S2 and S3 sites along the SI joint was performed. Needles were removed, and sterile dressings were applied. IMPRESSION: Successful SI joint ablation."