This prospective, randomized controlled trial aims to compare the analgesic efficacy of lumbar paravertebral block (L-PVB) and lumbar erector spinae plane block (L-ESPB) in elderly patients undergoing lumbar spine surgery. Effective postoperative pain management in this population is essential due to increased susceptibility to opioid-related adverse effects.

Participants aged 65 years and older will be randomly assigned to receive either bilateral L-PVB or bilateral L-ESPB in addition to standardized general anesthesia. The primary objective is to evaluate differences in postoperative opioid consumption within the first 48 hours after surgery. Secondary outcomes include pain intensity, intraoperative opioid use, time to mobilization, length of hospital stay, and incidence of opioid-related adverse events.

Lumbar spine surgery is associated with significant postoperative pain, particularly in elderly patients, who are at increased risk of opioid-related adverse effects such as respiratory depression, sedation, delirium, and delayed mobilization. Regional anesthesia techniques may improve postoperative analgesia and reduce opioid requirements in this population.

The lumbar paravertebral block (L-PVB) is a well-established technique providing segmental analgesia by targeting spinal nerves in the paravertebral space. The erector spinae plane block (L-ESPB), a newer interfascial plane block, has gained popularity due to its technical simplicity and favorable safety profile. However, comparative data on their effectiveness in lumbar spine surgery, especially in elderly patients, remain limited.

This study is designed as a prospective, randomized, controlled trial comparing L-PVB and L-ESPB in patients aged 65 years and older undergoing elective lumbar spine surgery under general anesthesia. Participants will be randomly allocated in a 1:1 ratio to receive either bilateral L-PVB or bilateral L-ESPB with a standardized dose of local anesthetic.

All patients will receive a standardized general anesthesia protocol and multimodal analgesia regimen. Postoperative pain management will follow a uniform protocol across both groups.

The primary endpoint is total opioid consumption within 48 hours after surgery, expressed as intravenous morphine equivalents. Secondary endpoints include intraoperative opioid consumption, postoperative pain scores at predefined time points, time to first mobilization, length of hospital stay, use of rescue analgesia, and incidence of opioid-related adverse effects. Exploratory analyses will include assessment of inflammatory markers.

Inclusion Criteria:

• ge ≥65 years
• Scheduled for elective lumbar spine surgery
• American Society of Anesthesiologists (ASA) physical status I-III
• Ability to assess pain using the Numeric Rating Scale (NRS)
• Provision of written informed consent

Exclusion Criteria:

• Refusal to participate
• Chronic opioid therapy
• Coagulation disorders
• Use of anticoagulant therapy contraindicating regional anesthesia
• Infection at the planned needle insertion site
• Allergy to ropivacaine or other study-related medications
• Severe hepatic failure
• Severe renal failure
• Cognitive impairment preventing reliable pain assessment
• Inability to cooperate with study procedures
• Extensive reoperation or surgery of unusually large extent that may interfere with outcome assessment
• Contraindications to general anesthesia or regional anesthesia

Individual participant data (IPD) underlying the results reported in this study, after de-identification, will be made available to researchers upon reasonable request. The shared data will include demographic data, intervention allocation, and outcome measures.

Data will be available beginning 6 months after publication of the primary results and will remain available for up to 5 years.

Access to the data will be provided to researchers who submit a methodologically sound proposal. Requests will be reviewed by the principal investigator. Data will be shared after approval of a data access agreement.