Background and Aims Postoperative pain after spine surgeries is a common type of acute, neuropathic pain with difficult to control. Systematic Lidocaine one of analgesic modalities that can be used to manage this type of pain. It has anti- inflammatory and analgesic benefits by decreasing the release of cytokines, and blocking the neural transmission. Human opiorphin inhibits the destruction of endogenous natural peptide, enkephalins, which releases physiologically in painful conditions, and can be used as objective indicator of acute pain. The aim of the study is to evaluate the role of using I.V Lidocaine infusion in declining the postoperative level of opiorphine and narcotic requirements.

Methods The study is a prospective; double blinded, randomized, controlled clinical trial, conducted at Assiut University hospital, Egypt. Forty Patients underwent major spine surgery were randomly allocated into equal groups. In first group, each patient received intra-operative lidocaine infusion whereas each patient in control group had a normal saline with equal volume and rate of lidocaine infusion. Analgesic requirements were monitored for 24 hours after surgery and two blood samples (preanesthetic induction and immediately after stopping Lidocaine infusion) were obtained from each patient to determine the level of Opiorphin. These blood samples were collected in plasma tubes, and Human ELISA kits was used to measure its level.

Conclusions In addition, its safety, our study suggests a significant role of systemic lidocaine infusion as an adjuvant in reducing the postoperative narcotic consumption and Opiorphin level in spine surgeries.