Cervical Aa. Dissection Flashcards
Vertebral Aa. Anatomy
- arises from the subclavian aa.
Comprised of 4 segments:
- V1-Extraosseous
- V2-Foraminal Segment
- V3-Extraspinal
- V4-Intradural Segment
V1-Extraosseous
origin to the C6 transverse foramen
V2-Foraminal Segment
C6-C1 foramina
V3-Extraspinal
exit of C1 to foramen; magnum dura
V4-Intradural Segment
magnum dura to basilar aa. junction
Describe the age-related changes in the cervical IV disc
the cervical vertebral discs become bipartite with age/degeneration
What arteries branch off the vertebral aa. before it joins with the basilar aa.?
- labyrinthine aa.
- anterior inferior cerebellar aa. (AICA)
- anterior spinal aa.
Pontine Aa.
supplies the pons
Labyrinthine Aa.
supplies cranial n. VII and VIII
Anterior and Posterior Inferior Cerebellar Aa.
supply the cerebellum
Superior Cerebellar Aa.
supplies the cerebellum, pons, and pineal gland
Posterior Cerebral Aa.
contributes to the blood supply of the temporal and occipital lobes, thalamus, lentiform nucleus, midbrain, geniculate bodies, pineal gland, choroid plexuses
Anterior Spinal Aa.
supplies the anterior 2/3rds of spinal cord
What is the most common vertebral aa. variant?
Persistent First Intersegmental Aa.
occurs when the vertebral aa. ascends through the vertebral foramen instead of the transverse foramen
Intimal Tear
vessel intima tears, flapping into the lumen
Dissection
a defect in the intima causes bleeding into the vessel wall forming a false lumen; flow compromise and possible thrombus formation
What are the three layers of an artery?
- intima
- media
- adventitia
Pseudoaneurysms
blood escapes through the vessel wall, forming an extravascular hematoma, a cavity can form w/in the hematoma
in some cases this causes obstruction of the lumen, resulting in occlusion by mural thrombosis
Transection
most severe; usually fatal
What are the cerebrovascular complications of VAD?
- stroke = 63%
- TIA = 14%
- Subarachnoid hemorrhage = 10%
Vertebral Aa. Lesions
- decreased blood flow not from stretching
- often results from impingement of vessel between C2 transverse foramen exit and C1 lateral mass edge
PICA obstruction causes:
lateral medullary syndrome infarct
Anterior Spinal Aa. causes
spinal cord ischemia
Vertebral Aa. dissections occur more in _____ patients, while Carotid Aa. dissections occur more in _______ patients
older; younger
Where is the most common type of extracranial internal carotid dissection?
2-3 cm above the bifurcation
Lateral Medullary Syndrome (Wallenberg’s)
- usually a result of vertebral aa. origin; less w/ PICA
- ipsilateral Horner syndrome
- pain and temperature sensation loss of the face
- weakness of palate, pharynx, and vocal cords
- cerebellar ataxia
- contralateral hemibody pain and temperature loss
What are the two imaging modalities listed in the ACR Appropriateness Criteria for suspected cervical aa. dissection?
CTA and MRA
What is the duration of the onset of S/Sx after Rx?
- immediate = 62.5%
- 5-30 mins = 12.5%
- 30 mins - 48 hours = 19%
- 48 hours to 7 days = 3%
- more than 1 wk = 1.5%
- not available = 1.5%
Risk of CVA is high in the 1st ___ weeks after CAD
two
Sx of Cervical Aa Dissection
- headache
- neck pain
- visual disturbance
- dizziness
- UE paresthesia
- facial paresthesia
- LE paresthesia
Carotid Aa Dissection usually begins with:
- ipsilateral neck pain or HA
- partial Horner’s Syndrome
- typically follows with retinal or cerebral ischemia
S/Sx of VAD/CVA
- occipitocervical pain
- dizziness, vertigo, light-headedness
- nausea and vomitins
- numbness, usually hemifacial
- ataxia, unsteady gait
- diplopia or other visual deficit
Vertebral Aa CVA Presentation
- ipsilateral Horner’s Syndrome
- ilsilateral limb ataxia
- contralateral analgesis of trunk and limbs
- ipsilateral CN IX-Xii abnormalities
Horner’s Syndrome
- anisocoria (ipsilateral pupil dilation)
- miosis (ipsilateral pupil constriction)
- ptosis (lid droop-Mueller’s muscle weakness)
- apparent enophthalmos
- facial anhidrosis and flushing
- sympathetic loss
Crossed Cheiro-oral Syndrome
- sensory disturbance unilateral peri-oral w/ contralateral hand/fingers
- suggestive of medullary involvement
- often occurs before Wallenberg syndrome (24-48 hrs.)
- predictor of CVA
Bow Hunter’s Syndrome most often affects which segments?
V2 and V3
S/Sx of Bow Hunter’s Syndrome
- syncope/near syncope
- drop attacks
- vertigo
- dizziness
- ataxia
- impaired vision
Etiology of Vertebral Artery Incident
- spontaneous = 43%
- cervical manipulation = 31%
- trivial trauma = 16%
- major trauma = 10%
What is the effect of cervical rotation on the vertebral aa?
blood flow in the contralateral aa. is reduced; however, the velocity increases d/t the Venturi tube effect
What segment of the vertebral aa. is most susceptible to mechanical forces during manipulation?
V-3; usually an injury to the intima between C1-C2 which propagates to V-3
What is the primary shortcoming of most studies examining the effect of vertebral aa testing on the vessel?
none of the studies have actually looked at the vessel’s ability to withstand the HLVA thrust
What are the problems with the available evidence on CAD?
- difficult to establish associations in rare events
- likely to be under-reported
- data mining and analysis can often identify or predict rare events
- cannot determine impact and probabilistic causal inference
Risk Factors for Cervical Aa CVA
- recent head or neck trauma
- neck manual therapy
- recent infection
- craniocervical vascular anomaly
- family hx of CVA
5Ds And 3Ns
- Diplopia
- Dizziness
- Drop Attacks
- Dysarthria
- Dysphagia
- Ataxia
- Nausea
- Numbness
- Nystagmus
What are the most frequent symptoms in the clinical presentation of VAD?
- visual disturbance
- dizziness
- imbalance
T/F: A hypoplastic vertebral artery (HVA) has an increased risk of CVA
True
What other injuries are associated with VAI in patients following trauma?
- facet dislocation w/ or w/o fxs
- C1-3 fx
- Type III odontoid fxs
- distraction MOI
