Safety and efficacy of dexmedetomidine in combination with ropivacaine for lumbar paravertebral block in posterior lumbar surgery: a randomized controlled trial

To evaluate the analgesic synergistic effect of ropivacaine lumbar paravertebral block (LPB) on patients undergoing lumbar surgery under general anesthesia, and to investigate whether dexmedetomidine as a local anesthetic adjuvant can further enhance analgesic efficacy, suppress perioperative stress-induced inflammatory responses, and improve postoperative recovery quality. A total of 120 patients scheduled for elective posterior lumbar surgery were enrolled and randomly assigned to three groups (n = 40 each) using a random number table. All patients underwent general anesthesia. Prior to anesthesia induction, the L group and DL group received ultrasound-guided bilateral lumbar paracentesis (LPB). The L group received 15 mL of 0.375% ropivacaine per side, while the DL group received 15 mL of 0.375% ropivacaine containing 0.5 µg/kg dexmedetomidine per side. The C group did not receive nerve block. The primary outcome measure was intraoperative sufentanil dosage, while secondary outcomes included postoperative numeric rating scale (NRS) scores for rest and activity, 15-item quality of recovery (QoR-15) scores, serum levels of inflammatory and stress markers, and the incidence of perioperative adverse events. Overall significant differences in intraoperative propofol and sufentanil doses were observed among the three groups (all adjusted P < 0.05). Post-hoc pairwise comparisons showed that Group L and Group DL had significantly lower intraoperative propofol and sufentanil doses compared with Group C (all Bonferroni-adjusted P < 0.0167). Furthermore, the doses of both agents were significantly lower in Group DL than in Group L (all Bonferroni-adjusted P < 0.0167). Compared with Group C, Groups L and DL demonstrated significantly reduced intraoperative sufentanil dosage, markedly lower NRS scores at all postoperative time points, significantly higher QoR-15 scale scores, and significantly lower serum levels of inflammatory and stress markers (all P < 0.05 after adjustment). All these outcomes in Group DL showed significant improvement compared to Group L (all P < 0.05 after adjustment). No statistically significant differences were observed in perioperative adverse event rates among the three groups (P > 0.05). Lopivacaine LPB effectively optimizes perioperative management for patients undergoing lumbar surgery. The addition of dexmedetomidine as an adjuvant further enhances analgesic efficacy, prolongs analgesia duration, suppresses perioperative stress-induced inflammatory responses, significantly improves early postoperative recovery quality, and demonstrates favorable short-term safety.