Predictors of Postoperative Pain Trajectories in Adolescent Idiopathic Scoliosis

Study Design. Prospective observational study. Objective. To determine the typical trajectory of pain during the first 6 months after spinal fusion surgery for adolescent idiopathic scoliosis (AIS) and the extent to which certain demographic, medical, and psychological variables modify this trajectory. Summary of Background Data. Pain after spinal fusion surgery for AIS may not improve predictably with elapsed healing time, and limited data exist on predictors of the course of pain during the initial months after surgery. Methods. Fifty patients ages 11 to 17 (mean = 14.5, standard deviation = 1.9) with AIS and undergoing posterior spinal fusion surgery comprised the study sample. Pain outcomes were assessed at 4 time points after surgery (2-week, 6-week, 3-month, and 6-month postsurgery). Preoperative predictor variables comprising demographics, baseline Cobb angle, body mass index, baseline pain, and psychological variables (anxiety, negative mood, and confidence in ability to control pain) were assessed 2 weeks before surgery. Perioperative predictor variables comprising pain, pain coping efficacy, negative mood, surgery length, length and lowest level of fusion, and analgesic use were assessed by self-report or record review. Multilevel growth models were used to evaluate hypotheses pertaining to predictors of pain trajectories. Results. Pain level on average declined predictably with days since surgery (b = -0.14 to -0.19, P < 0.01). For 22% of adolescents, pain was at or above baseline levels through 6 months after surgery. Greater baseline pain and anxiety predicted slower improvement in pain, whereas greater confidence in ability to control pain predicted more rapid declines in pain. None of the demographic or medical variables reliably modified postsurgical pain trajectories. Conclusion. Although pain typically declines predictably with healing time from spinal fusion surgery for AIS, higher preoperative levels of pain and anxiety may be risk factors for chronic postsurgical pain whereas greater pain coping efficacy may help optimize postsurgical pain outcomes.