concerning extension…

the case.

You receive a BAT call about a 31 year-old male who has come off his bicycle after running into a stationary car at ~30 km/hour. Bystanders report that he was thrown 3-5m and had a loss of consciousness of ~3 minutes without witnessed seizure activity.

On arrival, he is alert but confused (GCS E4 V4 M6). He is haemodynamically normal with the only injuries noted on primary survey being a significant left forehead haematoma and midline cervical tenderness at C5-7. His upper and lower limb neurological assessment, as well as his cranial nerve exam is normal.

You order him a CT brain and cervical spine as part of his trauma assessment…

[DDET What are the significant findings here ??]

The CT brain shows significant left frontal contusions.

CT C-spine shows a fracture of C6 involving the left facet joint with extension into the transverse foramen.

Here are the more detailed CT’s…

httpv://www.youtube.com/watch?v=vUZtH38sG1o

httpv://www.youtube.com/watch?v=31eRTgX87aw

[/DDET]

[DDET What about the vertebral artery ??]

Good question.

Vertebral Artery Injury.

• Occurs in ~0.1% of trauma patients (includes carotid & vertebral vessel injury).
  • ~1% of asymptomatic patients of blunt trauma & up to 2.7% of patients w/ Injury Severity Score ≥16.
  • >70% of vertebral artery injuries are associated w/ cervical spine fractures.
  • Majority are diagnosed after the development of secondary CNS ischaemia.
• Mechanism.
  • May follow mild events such as sudden rotation or hyperextension of neck.
  • Can occur from yoga, coughing or vomiting.
  • Seen more frequently in people with underlying pathology of vessel wall (eg. connective tissue disorders).
• The vertebral arteries are susceptible to mechanical injury due to relationship to neighbouring bony structures & ligaments.
  • Most susceptible to injury at the entrance into the transverse foramen (C6) & at C1-2.
  • Occurs due to shearing forces at junctions between fixed & mobile segments.
  • Intimal disruption may lead to complete thrombotic occlusion, subintimal haematoma, dissection and pseudoaneurysm formation.
• Diagnosis is often delayed as 17-35% of patients do not develop neurological signs for > 24 hours after injury.
  • Concomitant intoxication & head-injury can further delay diagnosis.
• Mortality 8-18%.

[/DDET]

[DDET Who should be screened for blunt VAI ?]

Patients of significant blunt head trauma with;

• GCS ≤ 8
• Basilar skull fracture
• Diffuse axonal injury
• Le Fort II or III facial fractures
• Facial haemorrhage
• Expanding neck haematoma
• Attempted hanging with anoxic brain injury
• Focal neurological signs that cannot be explained by the CT-brain.

[/DDET]

[DDET Which patterns of cervical spine fracture predict blunt VAI ?]

C-spine fracture:

• C1-C3
• Extension into foramen transversarium
• Subluxation or rotational component

[/DDET]

[DDET How do we screen for VAI ?]

• Catheter-based angiography (DSA)
  • Remains ‘gold standard’.
  • Risks include embolism, bleeding & reaction to contrast.
• CT-angiography
  • Multislice (8 or greater) just as good as formal angio.
  • Sn 97.7%, Sp 100% – compared to catheter angiography.
• MRI
  • Accurately diagnoses dissection, without risks associated with conventional angiography.
  • Provides other information also [eg. cerebral ischaemia, cord contusion, spinal ligamentous injury, size of thrombus].
• Ultrasound
  • Not adequate for screening. Poor sensitivity.

[/DDET]

[DDET The story continues…]

Given the mechanism of injury and the fracture through the transverse foramen, you order him a carotid and vertebral CT angiogram…

  

… which demonstrates interruption of flow in the left vertebral artery consistent with dissection.

[/DDET]

[DDET How should these be treated ?!?]

Generally based on the following Biffl et al Grading System…

• Grade I & II injuries should be treated w/ antithrombotic agents such as heparin or aspirin.
  • Heparin & antiplatelet therapy can be used with equivalent results.
  • Heparin started w/out a bolus.
  • Warfarin therapy should follow w/ target INR of 2-3 (for 3-6 months).
• Grade III injuries rarely resolve with observation or heparinisation.
  • Invasive therapy should be considered.
• Repeat imaging (CT-A) should be performed for grades I-III injuries at 7-10 days post-injury.

[/DDET]

[DDET References.]

1. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th Edition.
2. Rosenʼs Emergency Medicine. Concepts and Clinical Approach. 7th Edition
3. Bromberg WJ et al. Blunt cerebrovascular injury practice management guidelines: The eastern association for the surgery of trauma. J Trauma. 2010; 68; 471-477
4. Cothren CC et al. Cervical spine fracture patterns predictive of blunt vertebral artery injury. J Trauma. 2003 Nov;55(5):811-3.
5. Mueller CA et al. Vertebral artery injuries following cervical spine trauma: a prospective observational study. Eur Spine J. 2011 Dec;20(12):2202-9.
6. Desouza RM et al. Blunt traumatic vertebral artery injury: a clinical review. Eur Spine J. 2011 Sep;20(9):1405-16.
7. Biffl WL, Moore EE, Offner PJ, Brega KE, Franciose RJ, Burch JM. Blunt carotid arterial injuries: implications of a new grading scale. J Trauma. 1999;47:845– 853.

[/DDET]