Chronic postsurgical pain (CPSP) refers to pain that occurs or increases after surgery and lasts longer than 3 months. Severe acute postoperative pain is one of the major risk factors of CPSP. Spinal correction surgery is associated with severe pain due to large trauma and long duration. Ketamine and esketamine are N-methyl-D-aspartate receptor antagonists; they have antihyperalgesic effects and may reduce CPSP. Dexmedetomidine is an alpha 2-adrenoceptor agonist with sedative, anxiolytic, and analgesic effect; it is frequently used as an adjuvant to postoperative analgesia. In a previous trial of 200 patients after scoliosis correction surgery, mini-dose esketamine-dexmedetomidine in combination with opioids significantly improved analgesia and sleep quality but did not reduce CPSP. The authors speculate that increasing esketamine dose in the combination may further improve analgesia and, therefore, reduce the occurrence of CPSP.
Patients aged ≥18 years and body weight≥40 kg;
Scheduled to undergo scoliosis correction with pedicle screw fixation;
Required patient-controlled intravenous analgesia (PCIA) after surgery.
Preoperative sick sinus syndrome, severe sinus bradycardia (heart rate <50 beats per minute), atrioventricular block grade II or above without pacemaker, congenital heart disease, arrhythmia, or other serious cardiovascular diseases with a New York Heart Association class ≥III;
Patients with moderate or severe obstructive sleep apnea diagnosed preoperatively or according to the STOP-Bang score;
History of hyperthyroidism or pheochromocytoma;
History of schizophrenia, epilepsy, myasthenia gravis;