Adolescent idiopathic scoliosis (AIS) surgery is a major pediatric procedure requiring multidisciplinary management. Enhanced recovery after surgery (ERAS) programs have been developed to minimize the consequences of surgical stress, to optimize pain control and to promote the early recovery of the patient's autonomy. Such programs have largely proved their benefits in adults. In pediatrics, it is still poorly developed and evaluated. The main objective of this Before/After study was to implement an ERAS program after spine surgery and to evaluate its impact on the length of hospital stay and postoperative recovery after surgery for Adolescent Idiopathic Scoliosis.Methods: after validation by medical and paramedical teams, the ERAS protocol was applied to all adolescents undergoing a posterior spinal fusion (PSF). In association with the implementation of protocolized multimodal measures for early rehabilitation, the program included an intrathecal injection of morphine before surgical skin incision. Postoperative multimodal analgesia included two epidural catheters inserted at the end of the surgery to cover both the thoracic and lumbar areas. After approval by the local ethics committee and declaration to the CNIL, retrospective data from 73 adolescents undergoing a PSF surgery for AIS between january 2015 and january 2017 (Before ERAS) were compared with those of patients benefiting from the ERAS program since april 2018 (After ERAS). Patients undergoing a PSF surgery to correct neuromuscular scoliosis were not included in the analysis. After a descriptive analysis, two comparable populations (Before and After ERAS groups) were defined using a propensity score. The main outcome was the length of hospitalization. Time to first solid food intake, time to first ambulation, time to bowel movement and time for Foley catheter removal were also analyzed. Results: over the study period, 65 PSF surgeries benefited from the ERAS protocol, 35 of which were for AIS (30 neuromuscular scoliosis surgeries were not analyzed). After application of a propensity score, 32 patients per group were selected for the final analysis. The demographic and surgical characteristics of the Before and After ERAS groups were comparable. Implementation of the ERAS program was associated with a significant 25% reduction in the mean length of stay (8.97±1.38 days before ERAS vs 6.64±0.93 days after ERAS; p