Project Summary/Abstract More than 10% of the U.S. population seeks care for spine pain each year with rates of surgical procedures on the rise. One of the most challenging yet common sequelae of lumbar spine surgery is chronic post-surgical pain (CPSP). CPSP is associated with poor physical function and remains difficult to treat. Indeed, it is frequently treated with opioid medications, despite evidence that long term opioid use for the treatment of chronic pain may not be effective and may increase the risk of overdose-related death. Therefore, the need to prevent the transition from acute to chronic post-surgical pain is great, especially for patients undergoing lumbar spine surgery. Acceptance and Commitment Therapy (ACT) is a psychosocial intervention that has been effective in improving physical function and quality of life among patients with chronic pain as well treating opioid use disorders. Thus, it stands to reason that ACT may be a promising tool for the prevention of CPSP and long-term opioid use. It has also been modified into brief formats in order increase adherence and minimize treatment barriers such as cost and access. The present study aims to adapt and modify a brief presurgical ACT intervention aimed at preventing the transition to CPSP and reducing long-term opioid use. We will then assess the acceptability, feasibility, and preliminary efficacy of the finalized intervention to prevent the transition to CPSP and reduce post-surgical opioid use six months following lumbar spine surgery. Finally, we will identify psychosocial and psychophysical phenotypes associated with response to this intervention. Together, this study will afford me the opportunity to gain training in treatment development and implementation and development and execution of clinical trial while advancing my long-term goal of developing mechanistically-based nonpharmacologic interventions to prevent the development of CPSP and reduce the risk of long-term opioid use.