 SIJ Sensory Block: Eligible study subjects will initially undergo a lidocaine block of the PSN at the lateral crest under ultrasound guidance. Their index pain intensity prior to the block must be 210. Under ultrasound guidance, 0.5 mL of 2 lidocaine will be injected from the inferomedial border of the PSIS to the third transverse sacral tubercle at approximately 1.5 cm intervals along the skin surface. Following the local anesthetic block, the subject will be asked to complete a pain diary for 6 hours. Specifically, their baseline pain will be reassessed and their ability to perform functional activities will also be assessed over that time period. The results of this block will be compared to the results of conventional blocks done under fluoroscopy. 