ISCHEMIC OPTIC NEUROPATHY AFTER LUMBAR SPINE SURGERY

Objective: Study of clinical features of ischemic optic neuropathy (IO N) developing as a complication of multilevel lumbar spine surgery. De sign: Review of all cases of ION that developed within 2 weeks of spin e surgery at two academic institutions from 1990 to 1992, and a review of adequately reported cases of ION after other nonophthalmic procedu res. Results: Four new cases are reported in patients who ranged in ag e from 41 to 65 years. All four had undergone uneventful but prolonged (8 to 9 hours) spine surgery, during which blood pressure was deliber ately maintained between 84 and 100 mm Hg systolic and 45 to 65 mm Hg diastolic to reduce bleeding. Hemoglobin values fell 30 to 78 g/L duri ng surgery. Arteriosclerotic risk factors, including systemic hyperten sion, diabetes, coronary artery disease, and smoking, were present in three cases. There was no evidence of orbital soft-tissue injury, reti nal artery occlusion, or other neurologic deficits. The combination of hypotension and anemia has been noted in most of the 30 previously we ll-documented cases of ION after other nonophthalmic procedures. Concl usions: Multilevel lumbar laminectomy should be added to the list of p rocedures that may produce ION as an isolated complication. Deliberate hypotension maintained for long operative periods in patients with ar teriosclerotic risk factors may be the cause.