PROJECT SUMMARY Acute and chronic musculoskeletal (MSK) pain are important health concerns across the lifespan, and surgery is a chief inciting event for subsequent persistent pain. Eighty percent of adolescents undergoing major MSK surgery report severe acute pain, and 20% develop chronic postsurgical pain. Having chronic pain in childhood and adolescence increases risk for a continued negative trajectory of MSK pain and poor health outcomes in adulthood, contributing to the national pain crisis. This K24 award will provide critical support for Dr. Rabbitts, a NIAMS-supported Associate Professor of Anesthesiology and Pain Medicine at the University of Washington (UW). The candidate's programmatic research has focused on developing innovative methods to identify biopsychosocial contributors to acute and chronic pain following MSK surgery in adolescents. During the course of this award, she will complete currently supported research: R01AR073780 which aims to increase understanding of the transition from acute to chronic postsurgical pain and the causal mechanisms involved, and UH3HD102038 (HEAL clinical trial) which evaluates the effectiveness of an mHealth perioperative psychosocial intervention to reduce acute and chronic pain in adolescents undergoing major musculoskeletal surgery. The candidate will expand her interprofessional mentoring program to build a strong and diverse cohort of pain scientists equipped to develop and implement long-term solutions to the MSK pain crisis through prevention. This K24 will also allow extension of the candidate's perioperative research program through training in sleep methodologies and building new collaborations to forge a novel research direction focused on sleep. The specific aims of the two new research studies proposed are to: 1) test pain processing as a mediator in the relationship between adolescent sleep immediately following surgery and subsequent MSK pain at 2 months after spine surgery, and 2) to determine feasibility of peri-operative melatonin in youth undergoing MSK surgery. The four projects will provide mentees with rigorous methodological training in a broad range of pain research assessment and intervention methods. This will capitalize on the wealth of opportunities available at SCRI and UW to actively engage promising trainees in the candidate's role as a physician-scientist, including via the SCRI Pediatric Pain Research Postdoctoral Fellowship and the UW T32 Training Program in Anesthesiology and Perioperative Medicine Research. Release from clinical activities provided by this award will allow the candidate to expand mentees at the fellow level, while enhancing mentorship skills, to equip a new generation of pain researchers with necessary scientific and professional skills, resiliency, and commitment to pain science, to make a sustained impact on the pain crisis. The K24 will also accelerate the candidate's research momentum informing the Type II renewal of her R01 and a new U01 ef...