Combined regional and general anesthesia for orthopedic spine fusion surgery

Abstract

The combination of epidural anesthesia and general anesthesia is a sophisticated technique that offers many advantages for the patient undergoing lumbar spine fusion. With a proper understanding of the physiological and pharmacological considerations of this technique, it can be used to aggressively lower blood pressure intraoperatively, minimizing blood loss and maximizing the condition of the surgical field. Optimal postoperative pain management can be achieved with minimal side effects. The circulatory and cardiac effects of epidural hypotension must be appreciated before embarking on the use of this technique. The extensive sympathetic blockade achieved must be controlled by support of the circulation with an infusion of epinephrine. The technique involves a combination of a high-level epidural anesthetic using bupivacaine or ropivacaine. For safety, this is started before the induction of general anesthesia. Continuous monitoring of both intraarterial and central venous pressures must be performed to avoid precipitous hypotension and sudden bradycardia. Mean arterial pressure is targeted and controlled in the 50 to 60 mm Hg range. A light, general anesthetic with a nitrous narcotic technique is used to supplement the epidural. Epidural anesthesia alone has been found to diminish intraoperative blood loss by significant volumes. Epidural hypotensive anesthesia with proper technique further reduces blood loss, decreases the incidence of deep venous thrombosis, and is associated with an extremely low complication rate. This has been shown by numerous studies on patients who had total hip arthroplasties. Extensive epidural anesthesia applied to lumbar spine fusion surgery theoretically can achieve these same advantageous outcomes. Copyright © 2000 by W.B. Saunders Company