Ophthalmologic complications associated with prone positioning in spine surgery.

Visual impairment and blindness associated with general anesthesia and prone positioning in spine surgery have been increasing in incidence over the past several decades. Corneal abrasion, the most common ophthalmologic injury, is usually self-limiting. However, prolonged surgical procedures (>7 hours) associated with acute blood loss anemia, hypotension, and hypoxia may lead to posterior ischemic optic neuropathies. Direct pressure to the periorbital region of the eye can cause increased intraocular pressure and blindness as the result of central retinal artery occlusion. Hypoxia and cerebral embolism are associated with occipital cortical infarct or cortical blindness. The prognosis for visual recovery from ischemic neuropathy and retinal artery occlusion is poor. Cortical blindness usually improves to varying degrees. Effective treatment of perioperative amaurosis is lacking and usually ineffective, making prevention the cornerstone of management. To best prevent permanent ophthalmologic complications associated with prone positioning during spine surgery, orthopaedic surgeons should be aware of pathophysiology and related risks associated with spine surgery in the prone position, and initiate preventive measures and predictable treatment options.