Intrathecal Morphine and Opioid Consumption After Thoracotomy

Thoracotomy is associated with some of the most severe postoperative pain of any surgical procedure. Inadequate analgesia restricts inspiratory effort and impairs the ability to cough, predisposing patients to atelectasis, retained secretions and pneumonia, delaying mobilisation, and contributing to the development of chronic post-thoracotomy pain.

Intercostal nerve blockade, performed by the surgeon under direct vision before chest closure, is a widely used and technically reliable component of analgesia after thoracotomy. Its effect is nevertheless limited by the duration of action of the local anaesthetic, so that analgesic coverage may become inadequate during the remainder of the first postoperative day, when opioid requirements are typically highest. Thoracic epidural analgesia provides more prolonged coverage but is constrained by technical failure, catheter displacement, haemodynamic effects and contraindications related to anticoagulation.

Intrathecal morphine represents an alternative means of extending analgesia. It is a single-shot technique that is technically straightforward, carries a low failure rate, requires no indwelling catheter, and produces neither motor nor sensory blockade, thereby permitting early mobilisation. Whether adding intrathecal morphine to an intercostal block confers additional benefit in open thoracotomy has not been established: existing thoracotomy trials are small, more recent data derive predominantly from video-assisted thoracoscopic surgery, quality of recovery has not been assessed with a validated patient-reported instrument, and postoperative pulmonary function has been characterised only by single bedside flow measurements rather than comprehensive spirometry.

In this randomised controlled trial, all adults undergoing elective thoracotomy receive an intercostal nerve block together with standard multimodal analgesia. Patients are randomly allocated to receive, in addition, a single dose of intrathecal morphine or no intrathecal injection.

The primary outcome is total opioid consumption during the first 24 postoperative hours, expressed as intravenous morphine equivalents. Secondary outcomes comprise pain intensity at rest and on coughing, assessed with a visual analogue scale at seven time points over 24 hours; quality of recovery, assessed with the Quality of Recovery-15 (QoR-15) questionnaire at 24 hours; preoperative and postoperative pulmonary function (FVC, FEV1, FEV1/FVC, PEF and FEF25-75); time to first analgesic requirement; time to first mobilisation; and the incidence of opioid-related adverse effects.

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.