Comparison of Perineural Dexamethasone Versus Dexmedetomidine as Adjuvants to Erector Spinae Plane Block in Lumbar Spine Surgery: A Randomized, Double-blind, Controlled Trial

All participants will receive general anesthesia for surgery and, in addition, a nerve block on both sides of the lower back. The nerve block will be done with ultrasound guidance and will include ropivacaine plus either dexamethasone or dexmedetomidine. Patients will be randomly assigned to one of these two groups, and neither the patient nor the doctors checking pain after surgery will know which medication was used.

The main goal is to see how much opioid pain medicine patients need during the first 24 and 48 hours after surgery. Other things we will look at include how strong the pain is, how soon pain relief is necessary, if there are any side effects like nausea or low blood pressure, and if there are any complications related to the block.

This study will help doctors choose the best option to manage pain after spine surgery while reducing the need for opioids and their side effects.

Inclusion criteria

• Adults aged 18 to N/A (no limit)
• Scheduled for elective lumbar spine surgery (e.g., decompression or fusion) via posterior approach
• American Society of Anesthesiologists (ASA) physical status I-III
• Body weight ≥ 50 kg
• Ability to provide written informed consent
• Expected postoperative hospitalization of at least 48 hours

Exclusion criteria

• Known allergy or contraindication to ropivacaine, dexamethasone, or dexmedetomidine
• Infection at or near the site of block placement
• Coagulation disorders or current use of anticoagulant therapy (not discontinued per guidelines)
• Chronic opioid use or opioid dependence
• Neurological or psychiatric disorders interfering with pain assessment
• Diabetes mellitus with poorly controlled glycemia (e.g., HbA1c > 8%)
• Severe hepatic or renal dysfunction
• Body mass index (BMI) > 40 kg/m²
• Pregnancy or breastfeeding
• Refusal or inability to cooperate with the study protocol