A Multi-center Study of Genomic and Psychological Factors Affecting Postoperative and Chronic Pain in Children Undergoing Invasive (Spine) Surgery

Safe and effective analgesia is an important unmet medical need in children. Despite efforts to promote non-pharmacologic interventions, drug treatment remains the standard of care for children experiencing severe pain following surgery. Inadequate pain relief after invasive surgery, and side effects from analgesics such as morphine occur frequently in up to 50% of children. A study of patient controlled analgesia (PCA) morphine use after spine surgery in adolescents observed a 45% incidence of postoperative nausea and vomiting and 7% incidence of respiratory depression. Presently, evidence-based dosing guidelines for opioid therapy have not been ascertained in the pediatric patient population, and remains a trial and error method. Despite aggressive pain management after spine surgery, findings showed that neither children's pain nor their analgesic use diminished significantly over time. As such, there is a critical knowledge gap in the medical literature that significantly impacts the pediatric pain management. Moreover, chronic postsurgical pain (CPSP, defined as pain attributable to the surgical procedure lasting for more than 2 months after surgery critically impacts 13-30% of children having surgery, and leads to chronic pain as adults imposing extraordinary annual costs on the health care system ($560-635 billion). It has been recently shown that pain unpleasantness predicts the transition from acute to moderate/severe persistent post-surgical pain, whereas anxiety sensitivity predicts the maintenance of moderate/severe post-surgical pain from 6 to 12 months after surgery. Spine fusion in adolescents is a particularly painful surgery with 15% incidence of pain even 5 years after surgery, and hence will serve as a good surgical model to evaluate the behavioral and genetic predictors of chronic postoperative pain. In recognition of this therapeutic challenge the investigators plan to evaluate the determinants of inter-individual differences in opioid analgesic responsiveness, adverse effects, pain perception and predictors of chronic postoperative pain in children.