Postoperative pain after posterior lumbar stabilization surgery is related to soft tissue and muscle dissection and to manipulations and removal at the operation site. Most patients complain of severe pain at rest during the first 24 h after surgery. This pain increases considerably with mobilization because of the reflex spasm of paraspinal muscles that is triggered by the primary wound pain. During the following 48-72 h, postoperative back pain is generally moderate at rest, whereas it remains severe on movement and produces discomfort that can interfere with patient mobilization and, possibly, with discharge time. Despite the favourable effects of analgesia in the early postoperative period, this drug association may produce a number of well-known side effects, such as nausea, vomiting, respiratory depression, sedation, renal abnormality, and upper gastrointestinal and operative site bleeding. Local anesthetic infiltration of the surgical wound is a useful method in the treatment of postoperative pain after various surgical procedures. Ropivacaine is an interesting molecule for infiltration because of its vasoconstrictive properties and decreased neuro- and cardiotoxicity compared with bupivacaine.