SICU Meeting

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SICU Meeting

• Blood supply of spinal cord

Ri ??? 2003/03/24
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Blood supply of spinal cord

• One anterior spinal artery
• Supply the ventral 2/3 spinal cord
• Paired posterior spinal artery
• Supply the dorsal 1/3 spinal cord

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Blood supply of spinal cord

• A series of segmental arteries which arise from
• aorta
• branches of the subclavian artery
• vertebral a ascending cervical a
• branches of internal iliac artery
• lumbar a lateral sacral a

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Blood supply of spinal cord

• Segmental arteries

Spinal branch
Anterior radicular artery
Posterior radicular artery
Anterior Spinal Artery
Posterior Spinal Artery
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Radicular artery

• Adamkiewicz artery
• Arteria radicularis magna
• greater anterior radicular artery
• perfuse the spinal cord distal to its junction
  with the ASA
• ASA above the ARM is smaller in diameter compared
  with that below the ARM

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Blood supply of spinal cord

• Anterior spinal artery
• ? Central artery
• most of the anterior gray columns
• the ventral portions of the dorsal gray columns
• ? Pial plexus
• peripheral rim of white matter of the anterior
  two-thirds of the cord

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Blood supply of spinal cord

• Paired posterior spinal arteries
• ? direct penetrating vessels
• ? Pial plexus
• ? the dorsal third of the cord

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Anterior spinal artery syndrome

• Anterior spinal artery infarction
• Cause
• atheromas involving the aorta
• complication of thoracoabdominal aneurysm repair
• collagen vascular disease (SLE, polyarteritis)
• syphilitic angiitis
• dissecting aortic aneurysm
• embolic infarction (bacterial endocarditis)
• neurotoxic effect of iodinated contrast material

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Anterior spinal artery syndrome

• Transient pain
• the neck or back both legs
• dysesthetic pain feet ? abdomen, rapidly
• Motor paralysis rapid onset of weakness
• unable to walk within minutes
• Paralysis of sphincteric function.
• Incontinence of urine and feces

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Anterior spinal artery syndrome

• Sensory impairment below the level of the lesion
• loss of pain and thermal sensation below the
  level of the lesion
• vibration and proprioception was spared
• sparing of posterior columns

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Anterior spinal artery syndrome

• Some patients regain substantial motor function,
  mainly in the first month but extending over a
  year

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Posterior spinal artery syndrome

• uncommon
• does not give rise to a stereotyped syndrome.

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Clinical importance of ARM

• ARM supplies most of the blood to ASA, and ASA
  supplies 2/3 of anterior spinal artery
• Importance in operation with descending thoracic
  and thoraco-abdominal aorta

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Adamkiewicz artery

• Does the Adamkiewicz artery originate from the
  larger segmental arteries?
• The Journal of thoracic and cardiovascular
  surgery, May, 1999

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Adamkiewicz artery

• n102 adult cadavers
• Effective Adamkiewicz artery
• T5 L2
• gt 0.5mm in diameter

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Adamkiewicz artery

• Number of Adamkiewicz arteries per cadaver
• one artery 74
• More than two arteries 26
• Laterality of the adamkiewicz arteries
• 72 from the ICA/LA on the left side
• 28 from the ICA/LA on the right side

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Adamkiewicz artery

• Vertebral level of the Adamkiewicz artery
• 91 T8L1
• Diameter of the Adamkiewicz artery
• 0.501.49 mm

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Adamkiewicz artery
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Adamkiewicz artery

• All lower ICAs and upper LAs should be preserved,
  even if they are narrow.

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Clinical importance of ARM

• Operation with descending thoracic and
  thoraco-abdominal aorta
• and
• Spinal cord ischemia
• prevention of spinal cord ischaemia during
  descending thoracic and thoracoabdominal aortic
  surgery
• European journal of Cardio-thoracic Surgery
• 19 (2001), 203-213

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Spinal cord ischemia

• thoracic and thoracoabdominal aortic surgery
• ? the rate of paraplegia or paraparesis
• 540

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Pathogenesis of spinal cord ischemia

• Immediate neurological complications
• hypoperfusion of spinal cored
• second to hypoxic damage
• Delayed neurological complication
• POD1POD21
• Reperfusion ? hyperemia and free radical
• ? edema ? reduced perfusion

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Major cause of spinal cord injury

• The duration and degree of ischemia
• cross clamping time lt15min --gt 0 paraplegia
• cross claming time gt 60 min --gt 25-100
• Failure to re-establish blood flow to the spinal
  cord after repair

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Pre-OP prevention

• Angiography
• identify the ARM in 85 of pts
• Must use less toxic contrast medium
• MRA
• 69 (18/26)
• European Journal of cardio-thoracic surgery
  18(2000) 104-111
• Multi-detector row helical CT
• 90 (63/70)
• Radiology 2002, 223 39-45

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Intra-OP prevention

• Evoked potential monitoring
• SSEP
• Post. tibial nerve (medial malleolus) ? scalp
• MEP (myogenic)
• Scalp (transcranial) ? muscle
• Effects of anaesthetic drug neuromuscular
  blocker
• sensitivity and specificity MEP gt SSEP

The annals of thoracic surgery. 74(5) S1873-6
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Intra-OP prevention

• Reduction of the duration of ischemia
• Crawford aortic inlay technique
• Single-clamp repair technique
• Sequential aoritc clamping technique
• Reduction of the severity of ischemia
• Passive shunts
• Left atrial to femoral artery bypass (LAFA)

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Intra-OP prevention

• Reduction of the severity of ischemia
• Drainage of CSF
• To maintain the perfusion pressure
• Hypothemia
• Decrease oxygen demand and the metabolic rate
• Inhibit the synthesis and release of
  neruotransmitter which induced apoptosis
• epidural cooling technique

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Pharmacologic prevention

• Neuroprotective agents
• Papaverine ( CSF drainage)
• Naloxone ( CSF drainage)

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Pharmacologic prevention

• AMPA/kainate antagonist NBQX
• A2A agonist ATL-146e
• L-carnitine
• Dextrorphan
• ATP-sensitive K channel opener Nicorandil
• Pentobarbital
• FK506
• Trimetazidine
• Riluzole
• Methylprednisolone vit. C vit. E