The goal of this prospective controlled randomized clinical trial is to compare two intraoperative anesthetic patient management in Spinal surgery for idiopathic scoliosis. In particular in one Group of adolescent patients, the Erector Spinae (ESP) Block (an ultrasound-guided regional anesthesia technique) will be performed in addition to general anesthesia before surgical incision, while in the other Group the usual care (only General anesthesia, no Application of regional Block) will be applied. The fact that the ESP block acts on the dorsal branches of the spinal nerves, which innervate the paraspinal and vertebral muscles, makes this technique useful in the pain management of spine surgery. The main questions the study aims to answer are: 1. Verify if the pain measured in the two comparison groups in the first 24 postoperative hours is lower in the ESP Group. 2. Verify if the quantity of e.v opioid used intraoperatively, is lower in ESP Group 3. Verify if in ESP Group the Quantity of additional analgesics calculated by self-administered PCA doses of morphine (patient-controlled analgesia) in the first 24 hours postoperatively is lower than those administered in the usual care Group. 4. Verify if there are some differences between the two studied groups as regard the: Time to resume walking (expressed in hours from post-operative awakening); bowel movement recovery time (expressed in hours from post-operative awakening); Hospitalization time (expressed in days from the date of surgery until discharge).