Do Perineural Dexamethasone and Dexmedetomidine Improve Analgesia and Inflammatory Response After Lumbar Spine...

Postoperative pain after lumbar spine surgery often requires substantial opioid use. Perineural adjuvants such as dexamethasone and dexmedetomidine are increasingly used to prolong the duration of regional blocks and improve analgesic quality; however, their comparative effects remain uncertain. Ultrasound-guided erector spinae plane block (ESPB) is widely used as part of multimodal analgesia, but the selection of perineural adjuvants remains uncertain.

(1) Does adding adjuvants (dexamethasone or dexmedetomidine) to the ESPB result in longer time to first rescue opioid? (2) Do patients who received adjuvants have lower total opioid consumption in the first 48 hours after surgery, and do they have lower pain scores? (3) Does dexamethasone or dexmedetomidine result in lower postoperative systemic inflammatory indices?

This study was conducted at a tertiary academic referral center specializing in spine surgery. In this prospective, randomized, triple-blinded controlled trial, between March 2024 and December 2025, a total of 103 patients were assessed for eligibility. Of these, 94 were randomized. Four patients were excluded after randomization because of intraoperative changes in surgical plan or hemodynamic instability, leaving 96% (90) of adult patients undergoing posterior lumbar decompression with instrumented fusion. These patients were randomly assigned to receive ESPB in three groups: the ropivacaine alone (control), the ropivacaine plus dexamethasone, and the ropivacaine plus dexmedetomidine groups. The primary outcome was time to first rescue opioid administration. Secondary outcomes included cumulative opioid consumption within 48 hours, postoperative pain scores, and systemic inflammatory markers (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic immune-inflammation index). Patients were followed for 48 hours postoperatively.

Patients receiving dexamethasone or dexmedetomidine required rescue opioids later than those receiving ropivacaine alone. The mean ± SD time to first opioid administration was 6.2 ± 0.8 hours with ropivacaine alone versus 12.7 ± 2.7 hours with dexamethasone (mean difference 6.6 hours [95% confidence interval (CI) 5.6 to 7.7]; p < 0.001) and 15.5 ± 2.0 hours with dexmedetomidine (mean difference 9.6 hours [95% CI 8.5 to 10.5]; p < 0.001). Postoperative pain scores were reduced in both adjuvant groups at all assessed time points. Compared with dexmedetomidine and ropivacaine alone, dexamethasone was associated with lower postoperative systemic inflammatory indices, indicating greater attenuation of the inflammatory response.

Dexamethasone and dexmedetomidine demonstrate distinct and complementary effects when used as adjuvants to ESPB in lumbar spine surgery. Dexmedetomidine primarily enhances early postoperative analgesia, whereas dexamethasone more effectively reduces cumulative opioid consumption and systemic inflammation. These findings support a clinically actionable, mechanism-informed approach to selecting ESPB adjuvants according to the desired temporal analgesic profile and risk of prolonged postoperative opioid requirement.

Level I, therapeutic study.