Exam 3 - Lecture 5 Flashcards
Cerebral circulation does a great job of autoregulating just like
spinal circulation
3 fairly large arteries that run longitudinally down spine
1 anterior spinal artery and 2 posterior spinal arteries.
Source of blood for posterior spinal arteries near the top of cord comes from
Vertebral arteries and cerebral arteries
Specific cerebellar arteries that supply posterior spinal arteries
Posteroinferior cerebellar artery and and anteroinferior cerebellar artery
Feed vessel that connects intercostal artery to anterior and posterior spinal arteries
anterior and posterior Radicular arteries
Radicular arteries are also called
medullary and segmental arteries
can even combine both, or all 3 into one named artery. Segmental medullary radicular artery!
As we get lower in cord, the posterior arteries are supplied by
intercostal -> radicular arteries
Branching of feed vessels is ________ and ________
inconsistent; varies person to person.
Sometimes just from one side, sometimes just to front or back, higher or lower, etc. VERY INCONSISTENT
Typically, each side of cord has _________ radicular artery.
Just 1. Either goes to posterior or anterior, not both. Very seldomly breaks into two to supply both posterior and anterior.
Smaller arteries on outer surface of cord
coronal arteries
Spinal cord does not have ______ like the brain.
Collateral circulation (like circle of Willis)
Do coronal arteries wrap around entire cord?
No.
Difference with venous/artery placement
there is a posterior spinal vein in the posterior medial fissure
Intercostal arteries branch off of the
aorta
Route from thoracic aorta to cord (varies from level to level, but this is generalized possiblity) and how many arteries are typically per level?
Intercostal artery -> dorsal branch -> spinal branch -> radicular artery
just 1.
Where does spinal branch artery sit?
Branches off intercostal artery and sits on top of spinal root ganglia
What keeps the ribcage healthy and perfused?
Intercostal artery
Decently large arteries that come off abdominal aorta
Renal arteries
Big juicy artery that comes off abdominal aorta
Mesenteric artery
If we need to repair an aortic aneurysm, need to _________ the aorta and will cause _________ and may lead to things like ________
Clamp; downstream ischemia; acute renal failure (anything that is supplied below the clamp)
Anterior spinal artery covers ____ of the cord tissue blood supply.
75%
Posterior spinal arteries cover _____ of the cord tissue blood supply.
25% or 12.5% per posterior artery
It is correct to assume that ________ supplies more of the blood in the spinal cord.
Anterior spinal artery
How many anterior feed vessels in the neck of the spinal cord?
Typically, 2 per level of cord
How many anterior feed vessels in the thorax of the spinal cord?
Typically 2-3 per level of cord
How many anterior feed vessels in the lumbar area of the spinal cord?
Typically 1-2 per level of cord
Super important anterior feed artery that provides blood supply to the lower 2/3rds of the spinal cord
“Great” radicular artery of Adamkiewicz
The Great radicular artery comes in from the ______ side of the patient. Why?
Left. Because of the aorta.
The single level where the great radicular artery is located if you could only pick one? Range of vast majority of people? Overall total range?
T10
T9-T12
T5 - L5
Great radicular artery of Adamkiewicz is abbreviated as
GRA
If aneurysm is at the lower section of the aorta and you cross clamp below GRA
Then you should be good, as majority of blood supply goes through GRA, and it is not cut off.
If aneurysm is at the lower section of the aorta and you cross clamp above GRA
Then it is a cause of concern for patient waking up paralyzed since spinal cord isn’t getting normal blood supply.
What would be beneficial before operating on an Aortic Aneurysm if you have time?
Do imaging to see where GRA is, but often times an aortic aneurysm is an emergency.
Usually, the _______ is the most concerning with ischemic spinal cord injuries.
Motor function. Typically, sensory function isn’t as effected.
Generally, the _____ your GRA is, the safer it is for an aortic aneurysm repair.
The higher up. If its super low, more risk since youre more likely to clamp above it.
Perfusion pressure for cerebrum is (equation)
MAP - ICP
A high ICP will be an impediment to blood flow.
ICP is more or less of a concern for cord perfusion?
Less. its more flexible so its less effected by ICP.
When cross-clamping aorta, you should also be concerned about
CSF pressure.
How much does aorta cross clamping increase CSF pressure?
usually by about 10mm Hg, which would double the ICP to 20.
How to avoid CSF pressure rise during aorta clamp?
Put in a drain for CSF
Why are sensory deficits not a concern when waking up from an aorta aneurysm repair?
Because the posterior part of the cord isnt supplied with blood from the aorta.. only the anterior part of the cord is.
Things you could do to help with ischemia before aneurysm repair
Reduce inflammation and slow down metabolic rate of the cord so they chew through energy reserves better.
Whats another risk with aorta repair once the clamp is no longer needed? Why? How can you prevent this?
Reperfusion injury. The blood vessels are wide open, and the sudden rush of massive blood flow when the clamp is released can cause injury as it gets overwhelmed. Reduce oxygen levels or release clamp in a graded approach.
What causes rust on steel car?
Oxygen
what keeps oxygen induced damages in check?
Antioxidants