Group-based trajectory analysis of acute pain after spine surgery and risk factors for rebound pain

Group-based trajectory models are increasingly being applied in clinical research to map the developmental course of symptoms and assess heterogeneity in response to clinical interventions. In this review, we provide a nontechnical overview of group-based trajectory and growth mixture modeling alongside a sampling of how these models have been applied in clinical research. We discuss the challenges associated with the application of both types of group-based models and propose a set of preliminary guidelines for applied researchers to follow when reporting model results. Future directions in group-based modeling applications are discussed, including the use of trajectory models to facilitate causal inference when random assignment to treatment condition is not possible.

Severe pain after surgery remains a major problem, occurring in 20-40% of patients. Despite numerous published studies, the degree of pain following many types of surgery in everyday clinical practice is unknown. To improve postoperative pain therapy and develop procedure-specific, optimized pain-treatment protocols, types of surgery that may result in severe postoperative pain in everyday practice must first be identified. This study considered 115,775 patients from 578 surgical wards in 105 German hospitals. A total of 70,764 patients met the inclusion criteria. On the first postoperative day, patients were asked to rate their worst pain intensity since surgery (numeric rating scale, 0-10). All surgical procedures were assigned to 529 well-defined groups. When a group contained fewer than 20 patients, the data were excluded from analysis. Finally, 50,523 patients from 179 surgical groups were compared. The 40 procedures with the highest pain scores (median numeric rating scale, 6-7) included 22 orthopedic/trauma procedures on the extremities. Patients reported high pain scores after many "minor" surgical procedures, including appendectomy, cholecystectomy, hemorrhoidectomy, and tonsillectomy, which ranked among the 25 procedures with highest pain intensities. A number of "major" abdominal surgeries resulted in comparatively low pain scores, often because of sufficient epidural analgesia. Several common minor- to medium-level surgical procedures, including some with laparoscopic approaches, resulted in unexpectedly high levels of postoperative pain. To reduce the number of patients suffering from severe pain, patients undergoing so-called minor surgery should be monitored more closely, and postsurgical pain treatment needs to comply with existing procedure-specific pain-treatment recommendations.

Pain is a subjective and multidimensional experience that is often inadequately managed in clinical practice. Effective control of postoperative pain is important after anesthesia and surgery. A systematic review was conducted to identify the independent predictive factors for postoperative pain and analgesic consumption. The authors identified 48 eligible studies with 23,037 patients included in the final analysis. Preoperative pain, anxiety, age, and type of surgery were four significant predictors for postoperative pain. Type of surgery, age, and psychological distress were the significant predictors for analgesic consumption. Gender was not found to be a consistent predictor as traditionally believed. Early identification of the predictors in patients at risk of postoperative pain will allow more effective intervention and better management. The coefficient of determination of the predictive models was less than 54%. More vigorous studies with robust statistics and validated designs are needed to investigate this field of interest.