- Visit 1 (week -2): Pre-treatment screening (180 min). Participants will complete the informed consent process and are evaluated for inclusion/exclusion criteria. A medical/pain history and physical examination will be completed and participants will be asked to assess current back pain intensity on a VAS scale (0-100mm, no pain to worst possible pain). Participants complete questionnaires and return within 2 weeks for baseline MR imaging scans. Blood will be drawn for a baseline screen to obtain a complete blood count, chemistry panel, and liver function tests. Participants will be asked to discontinue their current pain medications 14 days (2 weeks) prior to their baseline visit and take only acetaminophen rescue medication during this time.