This prospective, observational, non-randomized clinical study aims to evaluate the intraoperative and postoperative effects of opioid-free multimodal anesthesia compared with opioid-containing anesthesia methods in adult patients undergoing lumbar spinal surgery. Patients will be managed according to routine clinical practice and assigned to one of three groups based on the analgesic strategy used by the attending anesthesiologist: (1) opioid-free anesthesia using multimodal agents and/or erector spinae plane (ESP) block; (2) ESP block plus intraoperative opioids; or (3) opioid-based anesthesia without regional blocks.
The primary objective is to compare postoperative pain control and opioid requirements within the first 48 hours after surgery. Secondary objectives include evaluating opioid-related side effects such as nausea, vomiting, pruritus, constipation, delayed mobilization, urinary retention, and postoperative complications classified according to the Clavien-Dindo system. Standard postoperative analgesia, including intravenous morphine patient-controlled analgesia (PCA), acetaminophen, and NSAIDs, will be provided for all patients.
The study aims to determine whether an opioid-free multimodal analgesic approach can reduce opioid consumption and related adverse effects while maintaining adequate analgesia in patients undergoing lumbar spinal surgery.
Adults aged 18 to 75 years
Elective surgery only
Scheduled for elective lumbar spinal surgery (lumbar spinal stenosis and/or lumbar disc herniation)
ASA physical status I-III
Age younger than 18 or older than 75
Inability or unwillingness to provide informed consent
Severe psychiatric disease or cognitive impairment
Emergency surgery cases
Adult patients aged 18 to 75 years undergoing elective lumbar spine surgery for conditions such as lumbar spinal stenosis, lumbar disc herniation, degenerative spondylolisthesis, or lumbar disc degeneration at Marmara University Pendik Training and Research Hospital. All participants are surgical patients who meet the clinical indication for lumbar spinal procedures. No healthy volunteers are included. Patients are assigned to one of three observational cohorts based on the anesthesia technique chosen by the attending anesthesiologist in routine clinical practice.
Cohort
Prospective
Opioid-free Anesthesia
DrugA multimodal opioid-free anesthetic regimen including ESP block and agents such as acetaminophen, lidocaine, dexmedetomidine, ketamine, magnesium sulfate, and esmolol. No intraoperative opioids are given. Applies to Groups:Group 1 (Opioid-Free Anesthesia Group)
Erector Spinae Plane Block
Procedure/SurgeryBefore surgery, after endotracheal intubation of the patient in the prone position, a bilateral ultrasound-guided erector spinae plane block was performed at the vertebral level above the surgical site, using 20 mL of 0.25% bupivacaine per side in the lumbar region." Applies to Groups: * Group 2 (for patients who receive ESP) * Group 3 (ESP + Opioid Group)
Opioid based Anesthesia
DrugIntraoperative opioid analgesia (e.g., remifentanil infusion and/or morphine) administered according to standard clinical practice. Applies to Groups: * Group 3 (ESP + Opioid Group) * Group 1 (Opioid-Based Anesthesia Group)
Intraoperative ANI Monitoring
DeviceThe Analgesia Nociception Index (ANI) device is used intraoperatively to continuously assess autonomic nervous system responses to nociceptive stimuli. ANI values are recorded in all participants and compared across anesthetic cohorts for evaluation of intraoperative analgesic adequacy.
Bispectral Index Monitoring
DeviceContinuous intraoperative depth of anesthesia monitoring using the Bispectral Index (BIS) device. BIS values are recorded throughout the procedure to assist in titration of anesthetic agents and to standardize anesthesia depth across study cohorts. The BIS device is used for monitoring only, and no device-related investigational procedures are performed.
Postoperative Opioid Consumption in the First 48 Hours
Total cumulative opioid consumption (morphine equivalents) within the first 48 postoperative hours, recorded via intravenous patient-controlled analgesia (PCA) and rescue opioid boluses. This measure evaluates the analgesic effectiveness of opioid-free versus opioid-containing intraoperative anesthesia strategies.
Postoperative Pain Intensity Assessed by Numerical Rating Scale (NRS)
Pain intensity will be measured using the Numerical Rating Scale (NRS), ranging from 0 (no pain) to 10 (worst imaginable pain). Assessments will be recorded at predefined postoperative time points.
Incidence of Opioid-Related Adverse Effects
Presence of nausea, vomiting, pruritus, constipation, urinary retention, sedation, and respiratory depression. Adverse effects will be compared among the three anesthesia groups.
Postoperative Complications According to the Clavien-Dindo Classification
Postoperative complications will be graded according to the Clavien-Dindo classification system (Grade I-V). Any deviation from the normal postoperative course will be recorded and classified, and the highest Clavien-Dindo grade observed during the follow-up period will be used for analysis.Complications were prospectively recorded and classified according to the Clavien-Dindo classification.
Time to First Analgesic Request
Time elapsed from arrival in the recovery unit to the first patient request for additional analgesia, with analgesic requests recorded at 6-hour intervals over a 48-hour postoperative period.
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