1. Regarding the blood supply to the spinal cord and its clinical relevance during aortic surgery:
- A.The artery of Adamkiewicz typically arises between T9 and T12 in the majority of individuals.
- B.The anterior spinal artery supplies the posterior one-third of the spinal cord, including the dorsal columns.
- C.Spinal cord perfusion pressure is calculated as distal mean aortic pressure minus the higher of CSF pressure or central venous pressure.
- D.Autoregulation of spinal cord blood flow is maintained during hypoxia and hypercapnia, ensuring constant perfusion.
- E.CSF drainage during thoracic aortic aneurysm repair aims to reduce CSF pressure and thereby improve spinal cord perfusion pressure.
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- A.TRUE
Why: The great radicular artery (artery of Adamkiewicz) is the major blood supply to the lower two-thirds of the spinal cord and originates between T9 and T12 in approximately 75% of cases.
- B.FALSE
Why: The anterior spinal artery supplies the anterior two-thirds of the spinal cord, including the motor tracts; the posterior spinal artery supplies the dorsal sensory columns.
- C.TRUE
Why: Spinal cord perfusion pressure is defined as distal mean aortic pressure minus CSF pressure or central venous pressure, whichever is greatest.
- D.FALSE
Why: During hypoxia or hypercapnia, autoregulation of spinal cord blood flow is lost, and flow becomes linearly related to perfusion pressure.
- E.TRUE
Why: CSF pressure often increases with aortic cross-clamping; draining CSF reduces this pressure and improves spinal cord perfusion pressure, lowering ischemic risk.