Lorri A. Lee, M.D.K., Domino, MD,MPH, K. Posner, PhD, et al.
One of the most devastating iatrogenic complications that can occur perioperatively is postoperative visual loss (POVL). Data from the American Society of Anesthesiologists (ASA) POVL Registry has provided important information on the perioperative characteristics of patients who developed ischemic optic neuropathy (ION) after spine surgery. However, it is unclear from these data if co-existing diseases, gender, hematocrit, blood pressure management, and other factors increase the risk of developing ION because there are no denominator data. We therefore propose to evaluate potential risk factors for ION after spine surgery using a multi-center randomized case control study in which patients with ION from the ASA POVL Registry (n = 80) will be compared to matched controls who did not develop ION after spine surgery. Determination of risk factors for perioperative ION after spine surgery could potentially identify 1) high risk pre-existing patient characteristics; and 2) perioperative events that may increase the risk of ION such as blood pressure management, type of fluid replacement, blood transfusion / hematocrit management, anesthesia / prone duration, or and use of vasopressors. These data could also be used to determine the odds ratio for developing ION for every additional hour of anesthesia and every liter of blood loss. These results could be used by both spine surgeons and anesthesiologists to improve patient safety by influencing appropriate patient selection and perioperative anesthetic and surgical management of prolonged spine operations with the goal of reducing the incidence of this devastating complication. Pharmacokinetics of Intrathecal Drug Infusions.