Perioperative visual loss (POVL) is a devastating injury that has been reported infrequently after nonocular surgery. The most common cause of POVL is ischemic optic neuropathy (ION). Increasing numbers of cases of ION are being reported after spine surgery, but the etiology of postoperative ION remains poorly understood. After a MEDLINE search of the literature, we reviewed published case reports of ION, specifically those reported after spine surgery performed with the patient in the prone position. Most of the cases involved posterior ION (PION, n = 17), and the remainder anterior (AION, n = 5). Most patients had no or few preoperative vascular disease risk factors. All except one PION and 2 of 5 AION cases reported symptom onset within the first 24 hours after surgery. Visual loss was frequently bilateral (40% of AION, 47% of PION cases). Mean operative time exceeded 450 minutes. The lowest average intraoperative mean arterial blood pressure was 64 mm Hg and the mean lowest intraoperative hematocrit was 27%. The average blood loss was 1.7 L for AION and 5 L for PION patients. PION patients received an average of 8 L of crystalloid solution and 2.2 L of colloid intraoperatively. This compilation of case reports suggests that a combination of prolonged surgery in the prone position, decreased ocular perfusion pressure, blood loss and anemia/hemodilution, and infusion of large quantities of intravenous fluids are some of the potential factors involved in the etiology of postoperative ION. However, levels of blood pressure and anemia intraoperatively were frequently at levels considered acceptable in anesthesia practice. The etiology of postoperative ION remains incompletely understood. Potential strategies to avoid this complication are discussed.
From the *Pritzker School of Medicine, University of Chicago, Chicago, Illinois; †Departments of Ophthalmology, Neurology, and Neurosurgery, Emory University, Atlanta, Georgia; and ‡Departments of Ophthalmology and Visual Science, and §Anesthesia and Critical Care, University of Chicago, Chicago, Illinois.
Received for publication May 26, 2004; accepted August 2, 2004.
Supported in part by National Institutes of Health Grants EY10343 (S.R.), and EY06360 (Department of Ophthalmology, Emory University); and Research to Prevent Blindness, Inc. (Department of Ophthalmology, Emory University). Dr. Ho is the recipient of Student Research Fellowships from the American Heart Association and the American Academy of Neurology. Dr. Newman is the recipient of a Research to Prevent Blindness Lew R. Wasserman Merit Award.
Reprints: Steven Roth, MD, Department of Anesthesia and Critical Care, University of Chicago, 5841 South Maryland, MC 4028, Chicago, IL 60637 (e-mail: email@example.com).