Spinal manipulation showed no advantage over standard medical care, and adding spinal manipulation to supported self-management did not provide any additional benefit. Supported self-management combined with spinal manipulation also resulted in reduced disability relative to medical care. Adding spinal manipulation to supported self-management did not provide additional benefit beyond self-management alone. Spinal manipulation alone provided no clear benefit, highlighting the importance of self-management–focused strategies rather than symptom-driven interventions alone. Spinal Manipulation and Clinician-Supported Biopsychosocial Self-Management for Acute Back Pain: The PACBACK Randomized Clinical Trial.