ED Physical Therapy for Chronic Low Back Pain

This trial is ancillary to an ongoing single-center physician-randomized trial of an embedded physical therapy intervention versus usual care in ED patients with acute low back pain (NEED-PT, NCT04921449), comparing a primary outcome of pain-related functioning and a secondary outcome of opioid use at three months. The main trial aims to enroll up to 360 participants with acute low back pain, defined as ≤ 30 days in duration and no history of lumber surgery or chronic low back pain. Using the same procedures and physician-randomization assignments as the main trial, this ancillary trial will enroll an additional 200 participants with chronic low back pain (i.e. non-acute low back pain) in order to obtain initial point estimates for the outcomes of interest and assess participant enrollment and retention rates in this population. The ancillary trial's sample size of 200 participants is an estimate of patient accrual over the anticipated remaining duration of the main trial (i.e., there is not a separate power calculation for this ancillary trial given its exploratory nature), and the actual number accrued may differ depending on the main trial's actual end date.