Ninety patients undergoing posterior lumbosacral spine fixation were randomized to receive either dexmedetomidine plus bupivacaine (n=30), bupivacaine alone (n=30), or saline (n=30) for bilateral ultrasound-guided erector spinae plane block (ESPB). Pain management included IV paracetamol and patient-controlled morphine analgesia. Outcomes included active and passive pain scores (VAS), opioid consumption, need for rescue analgesia, and incidence of side effects, assessed over 48 hours. Overall, the results revealed that the dexmedetomidine-bupivacaine group had significantly lower pain scores, reduced opioid use, fewer rescue analgesia needs, and fewer opioid-related side effects. These findings suggest that adding dexmedetomidine enhances the efficacy and duration of ESPB for postoperative analgesia in spine surgery without increasing adverse events.