Development and Validation of a Clinical Prediction Score for Poor Postoperative Pain Control Following Elective Spine Surgery

Abstract

Abstract INTRODUCTION Approximately, 30% to 64% of people suffer from poorly controlled pain following spine surgery leading to patient dissatisfaction and poor outcomes. The ability to identify these patients before surgery may be useful to facilitate patient education and the development of personalized clinical-care pathways to improve postoperative pain management. METHODS Adult patients were consecutively enrolled through the Canadian Spine Outcomes and Research Network registry and were included if they underwent inpatient elective cervical or thoracolumbar spine surgery. The outcome was poor postoperative pain control defined as the mean numeric rating scale for pain >4 in the first 24-h after surgery. A split-sample design was used to develop and validate the prediction model. The prediction model was transformed into a risk-based score and simplified to a 3-tier Calgary Postoperative Pain after Spine Surgery (CAPPS) score to maximize clinical utility. RESULTS Of 1300 patients, 57% had poorly controlled pain following spine surgery. Seven significant predictors were associated with poor pain control: younger age, female sex, preoperative daily opioid medication use, higher preoperative neck or back pain intensity, higher PHQ-9 depression score, > = 3 motion segment operation, and fusion surgery. Notably, chronic pain and minimally invasive surgery were not associated with pain control status. The model was discriminative (c-statistics 0.74 [95% CI = 0.71-0.77]) and accurate (Hosmer-Lemeshow goodness-of-fit, P = .99) at predicting the outcome. Patients classified to low-, high-, and extreme-risk groups by the CAPPS score had 32%, 63%, and 85% predicted probability of developing poor postoperative pain control, respectively. This closely mirrored the observed probability of 37%, 62%, and 81% in the same risk-groups for poor pain control in the validation cohort. CONCLUSION This internally validated CAPPS score based on 7 easily acquired characteristics accurately predicted the probability of developing poor pain control after spine surgery. This score can be used to develop personalized preoperative and perioperative treatment strategies to improve pain outcomes.