Effects of Different Doses of Esketamine on Postoperative Analgesia and Recovery Quality in Lumbar Decompression Surgery: A Randomized Controlled Trial Focusing on the Advantages of Sub-Anesthetic Doses

Abstract Background: The optimal esketamine dose for opioid-sparing analgesia in lumbar decompression surgery remains controversial, particularly regarding its dose-dependent effects on recovery quality and safety. Methods: In this single-center, parallel-group, assessor-blinded randomized controlled trial, 120 patients were allocated via computer-generated randomization (1:1:1:1) to four groups:Group N: Sufentanil2.5µg/kg (control);Groups S1–S3: Esketamine 0.25/0.5/1.0 mg/kg + sufentanil 1.5µg/kg.Primary outcomes included postoperative analgesic consumption, rescue analgesia requirements, and 12-hour VAS scores. Secondary outcomes comprised stress markers and adverse events. Results: No significant differences were observed in rescue analgesia frequency among groups (P > 0.05). However, Group S1 (0.25 mg/kg esketamine) demonstrated significantly lower VAS scores versus Group N (mean difference − 1.8, 95% CI − 2.1 to − 1.5; P < 0.001) and a lower incidence of psychiatric symptoms than Group S3 (6.67% vs. 20.0%; RR 0.33, P = 0.032). Stress markers showed no dose-dependent trends (P > 0.05). While overall adverse event rates were comparable (P > 0.05), high-dose esketamine (S3) was associated with increased hypotension and dissociative symptoms (P < 0.05). Conclusions: Esketamine 0.25 mg/kg effectively reduces sufentanil consumption, prolongs analgesia, and achieves an optimal balance between efficacy and safety in lumbar decompression surgery. Trial registration: ChiCTR-2500095890, 15 January 2025.