Selective vulnerability of the lumbosacral spinal cord after cardiac arrest and hypotension.

Abstract

It is generally accepted that the gray matter in the watershed area of the midthoracic level of the spinal cord is the ischemic watershed zone of the spinal cord. We performed a retrospective study to reevaluate the frequency and distribution of spinal cord injury after a global ischemic event. Clinical files and neuropathology specimens of all adult patients with either a well-documented cardiac arrest or a severe hypotensive episode, as well as pathologically confirmed ischemic encephalopathy and/or myelopathy, were reviewed by an independent reviewer. Among 145 cases satisfying selection criteria, ischemic myelopathy was found in 46% of patients dying after either a cardiac arrest or a severe hypotensive episode. Among the patients with myelopathy, predominant involvement of the lumbosacral level with relative sparing of thoracic levels was observed in >95% of cardiac arrest and hypotensive patients. None of the examined patients developed neuronal necrosis limited to the thoracic level only. Our findings indicate a greater vulnerability of neurons in the lumbar or lumbosacral spinal cord to ischemia than other levels of the spinal cord.