Postoperative delirium is one of the most frequent adverse events following elective non-cardiac surgery and is associated with cognitive impairment at discharge, as well as in-hospital and long-term mortality, however, despite being a well-recognized problem there is a dearth of effective interventions for prevention and management. A modifiable risk factor associated with postoperative delirium is poor postoperative pain control, and by improving the pain regimen the investigators may be able to decrease the incidence and/or severity of postoperative delirium. In this study, the investigators seek to study whether a postoperative intravenous infusion of lidocaine, known to improve pain control in other contexts, can decrease the risk of postoperative delirium and other opioid-related side effects, following major reconstructive spinal surgery.