Spine surgery often causes severe postoperative pain. Currently, our hospital routinely uses ropivacaine for local infiltration analgesia (lasting 6-8 hours). This study evaluates liposomal bupivacaine, a novel long-acting local anesthetic providing up to 72 hours of pain relief, in patients undergoing posterior lumbar spine surgery. Through a randomized controlled design, we will compare the two drugs' effects on pain control within 72 hours and opioid consumption. Both regimens are guideline-recommended and safe.