Fifty (fifty) patients undergoing elective lumbar spine surgery were randomized to receive bilateral TiPVB with bupivacaine 0.20% plus 4 mg dexamethasone per side (n = 25) or bupivacaine 0.20% plus saline per side (n = 25), in addition to standardized general anesthesia and PCA protocols. The primary outcome was time to first analgesic requirement. Secondary outcomes included total morphine consumption over 24 hours, VAS pain scores (0–10) at prespecified time points, hemodynamics/sedation, and adverse events (PONV, pruritus, respiratory depression). Outcomes were assessed up to 24 hours postoperatively. Overall, the results of the study revealed that dexamethasone significantly prolonged analgesia (mean ~18.4 h vs 8.7 h) and reduced morphine use (mean ~3.1 mg vs 8.4 mg), with lower VAS scores after 6 hours and similar safety. These findings suggest that adding 4 mg perineural dexamethasone to bupivacaine in TiPVB enhances early postoperative analgesia after lumbar spine surgery without increasing adverse events.