The purpose of this research study is to evaluate patient outcomes following treatment with the SPRINT® Peripheral Nerve Stimulation (PNS) System for chronic posterior sacroiliac joint complex (PSIJC) pain. The PNS system is a temporary nerve stimulator, which provides non-surgical treatment that reduces pain by sending electrical pulses to the nerves that carry signals to/from your spinal cord. SPRINT PNS system is currently FDA approved to treat pain after surgery, pain after trauma, and pain that is difficult to treat. The study will consist of 3 total visits for each participant, over the course of roughly 6 months.