Subdural hematoma induced by cerebrospinal fluid drainage

A 50-year-old man underwent replacement of the descending thoracic aorta for a DeBakey type III-b chronic dissecting aortic aneurysm. During the surgery, lumbar cerebrospinal fluid (CSF) drainage with a 10 cm H₂O pop-off pressure was used to protect against spinal cord ischemia. During cardiopuhnonary bypass, the patient’s pupils were isocoric, but anisocoric at end of the operation. As computed tomography of the brain showed right subdural hematoma, neurosurgical drainage was instituted emergently. Although some neurological deficit remained, the patient recovered well and was discharged. This case provides a strong reminder that CSF drainage for spinal cord protection against ischemia might induce subdural hematoma, which can be catastrophic during an operation for thoracoabdominal aortic aneurysm.