- 1. 18 years old, or older 2. Unilateral or Bilateral LBP or Buttocks Pain for greater than six months with a 3 day average VAS greater or equal to 4 on a 1-10 scale 3. Tenderness over the SI joint 4. 75% or greater relief of pain (with return to baseline) during the local anesthetic phase of two separate, one fluoroscopically guided intra-articular SI joint injection and one lateral branch block (see Appendix A) 5. Stable medications for pain for the last seven days 6. Have used at least 3 alternative treatments for pain without success (se 7. BMI less than 35.0