Abstract
BACKGROUND: Positioning for neuraxial anesthesia in geriatric lower extremity fracture surgery is painful and can destabilize hemodynamics. Sedation-analgesia must balance effective analgesia with respiratory safety and physiologic stability. METHODS: This single-center retrospective cohort study included patients aged ≥65 years undergoing lower extremity fracture surgery under spinal anesthesia who received S-ketamine plus dexmedetomidine (Group A, n = 48) or S-ketamine plus propofol (Group B, n = 46). Primary outcomes included a numerical rating scale (NRS) positioning pain score of 0-10 and an ordinal posture quality score measured at five stages (T1-T5). Repeated measures were analyzed using mixed-effects models (group, stage, group×stage; random: patient) with covariate adjustment. Stage-wise contrasts were Holm-corrected. RESULTS: A total of 100 records were screened, and 94 patients were analyzed. Group×stage interactions were significant for pain and posture quality. Group A had lower pain during the most noxious stages (T3-T5; adjusted differences -0.42 to -0.50) and higher odds of better posture quality (OR 2.30-2.70). Physiological differences were modest and stage-specific, with slightly higher SpO(2) and lower heart rate (HR)/mean arterial pressure (MAP) at T2-T3. Postoperative NRS differed only at 12 h. Adverse events were infrequent; delirium was identified from routine documentation without a standardized instrument (0/48 vs. 2/46). CONCLUSION: In this retrospective cohort, dexmedetomidine-based sedation with S-ketamine was associated with improved comfort and cooperation during spinal positioning compared with propofol-based sedation, while adverse events were infrequent in both groups.