Can one spinal injection cut opioid use after chest surgery?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adults aged 18 years or older. * Patients scheduled for elective open thoracotomy under general anesthesia. * Patients undergoing thoracotomy through a standard posterolateral or anterolateral thoracotomy incision. * Patients eligible to receive surgeon-performed intercostal nerve blockade as part of the standard postoperative analgesic protocol. * American Society of Anesthesiologists (ASA) physical status I-III. * Ability to understand the study procedures and comply with the study assessments. * Provision of written informed consent before enrollment. Exclusion Criteria: * Age \<18 years. * Emergency or urgent thoracic surgery. * Video-assisted thoracoscopic surgery (VATS), robotic-assisted thoracic surgery, or other minimally invasive procedures without an open thoracotomy. * Previous thoracic surgery on the operative side that may significantly alter thoracic wall innervation. * Contraindication to neuraxial anesthesia or intrathecal morphine, including: * Coagulopathy or clinically significant bleeding disorder. * Therapeutic anticoagulation precluding neuraxial procedures. * Local infection at the intended puncture site or systemic infection. * Known hypersensitivity to morphine or other study medications. * Severe spinal anatomical abnormalities preventing safe intrathecal access. * Increased intracranial pressure or other contraindications to spinal anesthesia. * Chronic opioid use or long-term opioid therapy before surgery. * Pre-existing chronic pain requiring regular analgesic medication. * Severe pre-existing pulmonary disease that would substantially interfere with postoperative pulmonary function assessment. * Pre-existing neurological or neuromuscular disease that could affect respiratory function, pain assessment, or mobilization. * Severe hepatic or renal dysfunction that could significantly affect opioid metabolism or elimination. * Pregnancy or breastfeeding. * Inability to communicate adequately or reliably report pain or complete the Quality of Recovery-15 (QoR-15) questionnaire. * Inability to perform reliable preoperative or postoperative pulmonary function testing. * Any condition judged by the investigator to make participation unsafe or to interfere substantially with study outcomes. * Refusal to participate or withdrawal of informed consent.