2. Head and Facial Injury Scott Marquis, MD

3. Overview • Head injury • What to look for • Appropriate management • Facial injury • Review

4. Head and brain trauma • ~ 1,500,000 head injuries annually • ~ 230,000 hospitalized and survive • ~ 50,000 deaths • 1/3 all injury-related deaths • Severity • 75% mild • 10% moderate • 10% severe (35% mortality, 5% c-spine fx) • 80,000-90,000 significant long-term disability

5. Head & brain trauma • Risk Groups • Highest: Males 15-24 yrs of age • Very young children: 6 mos to 2 yrs of age • Young school age children • Elderly >75 yrs

6. Head injury • Broad and Inclusive Term • Traumatic insult to the head that may result in injury to soft tissue, bony structures, and/or brain injury • Blunt Trauma • Penetrating Trauma

7. Brain injury • “A traumatic insult to the brain capable of producing physical, intellectual, emotional, social and vocational changes” • Three broad categories • Focal injury • Cerebral contusion • Intracranial hemorrhage • Epidural hemorrhage • Subarachnoid hemorrhage • Diffuse Axonal Injury • Concussion

8. Mechanisms of head injury • Motor vehicle crashes, MVC • Most common cause of head trauma • Most common cause of subdural hematoma • Sports injuries • Falls • Common in elderly and in presence of alcohol • Associated with subdural hematomas • Penetrating trauma • Missiles more common than sharp projectiles

9. Categories of injury • Coup injury • Directly posterior to point of impact • More common when front of head struck • Contrecoup injury • Directly opposite the point of impact • More common when back of head struck

11. Categories of injury • Diffuse axonal injury (DAI) • Shearing, tearing or stretching of nerve fibers • More common with vehicle occupant and pedestrian • Focal injury • Limited and identifiable site of injury

12. Causes of brain injury • Direct (primary) causes • Impact • Mechanical disruption of cells • Vascular permeability or disruption • Indirect (secondary or tertiary) causes • Secondary • Edema, hemorrhage, infection, inadequate perfusion, tissue hypoxia, pressure • Tertiary • Apnea, hypotension, pulmonary resistance, ECG changes

13. The brain is enclosed in a box

14. Brain anatomy • Occupies 80% of intracranial space • Divisions • Cerebrum • Cerebellum • Brain Stem

15. Brain anatomy • Cerebral spinal fluid, CSF • Clear, colorless • Circulates throughout brain and spinal cord • Cushions and protects • Ventricles • Center of brain • Secrete CSF by filtering blood • Forms blood-brain barrier

16. Brain anatomy • Blood Supply • Vertebral arteries • Supply posterior brain (cerebellum and brain stem) • Carotid arteries • Most of cerebrum

18. Brain anatomy • Meninges • Dura mater: tough outer layer, separates cerebellum from cerebral structures, landmark for lesions • Arachnoid: web-like, venous vessels that reabsorb CSF • Pia mater: directly attached to brain tissue

21. Scalp lacerations • Scalp laceration or avulsion • Most common injury • Vascularity = diffuse bleeding • Generally does not cause hypovolemia in adults • Can produce hypovolemia in children

22. Scalp anatomy • Scalp • S: skin • C: connective tissue • A: aponeurosis (galea) • L: loose areolar tissue • P: pericranium • Scalp very vascular • major blood loss • watch kids and adults with prolonged extrication

23. Skull fracture

24. Skull fracture • Present in 60% of pts with severe head injury • Types: • Linear: usually incidental finding on CT • Depressed: mechanism is usually intense blow to scalp with object of small surface area. Surgical repair needed if depressed more than 5mm

25. Skull fracture • Types • Basilar: blow to temporal (most often), parietal, occipital area • Signs • Hemotympanum or bloody ear discharge • Rhinorrhea or otorrhea • Battle’s sign • Racoon’s eyes • Cranial nerve palsies

27. Closed head injuries • Focal • Contusion • Epidural hematoma • Subdural hematoma • Intracerebral • Diffuse (most common type of head injury) • Mild concussion • Classic concussion • Diffuse Axonal Injury (DAI)

29. Blood between skull and dura Usually arterial tear Middle meningeal artery Causes increased ICP Epidural hematoma

30. Epidural hematoma • Unconsciousness followed by lucid interval • Rapid deterioration • Decreased LOC, headache, nausea, vomiting • Hemiparesis, hemiplegia • Unequal pupils (dilated on side of clot) • Increase BP, decreased pulse (Cushing’s reflex)

32. Between dura mater and arachnoid More common Usually venous Bridging veins between cortex and dura Causes increased intracranial pressure Subdural Hematoma

33. Subdural hematoma • Slower onset • Increased ICP • Headache, decreased LOC, unequal pupils • Increased BP, decreased pulse • Hemiparesis, hemiplegia

34. Intracerebral hematoma • Usually due to laceration of brain • Bleeding into cerebral substance • Associated with other injuries • DAI • Neuro deficits depend on region involved and size • Repetitive with frontal lobe • Increased ICP

35. Concussion • Transient loss of consciousness • Retrograde amnesia, confusion • Resolves spontaneously without deficit • Usually due to blunt head trauma

37. Diffuse axonal injury • Tearing or shearing of nerve fibers at time of impact • Rapid acceleration-deceleration injury (MVA) • Functional or physiologic dysfunction • Not gross anatomic abnormality • Most common CT finding after severe head trauma

38. Diffuse axonal injury • Prolonged post-traumatic coma not due to mass lesion or ischemic insults • Coma begins at time of trauma • Usually evidence of decorticate or decerebrate posturing, autonomic dysfunction (HTN, fever)

40. Penetrating head injury • Severity depends on • Energy of missile • Path • Amount of scatter of bone and metal fragments • Presence of mass lesion • Accompanied by • Severe face and neck injuries • Significant blood loss • Difficult airway • Spinal instability

44. What the brain needs • High metabolic rate • Consumes 20% of body’s oxygen • Largest user of glucose • Requires thiamine • Can not store nutrients

45. More on brain workings • Perfusion • Cerebral blood flow (CBF) • Dependent upon CPP • Flow requires pressure gradient • Cerebral perfusion pressure (CPP) • Pressure moving the blood through the cranium • Autoregulation allows BP change to maintain CPP • CPP = mean arterial pressure (MAP) - intracranial pressure (ICP)

46. More on brain workings • Perfusion • Mean Arterial Pressure (MAP) • Largely dependent on cerebral vascular resistance (CVR) since diastolic is main component • Blood volume and myocardial contractility • MAP = diastolic + 1/3 pulse pressure • Usually require MAP of at least 60 mm Hg to perfuse brain

47. More on brain workings • Perfusion • Intracranial pressure (ICP) • Edema, hemorrhage • ICP usually 10-15 mm Hg • Cerebral perfusion pressure CPP = MAP - ICP

50. What goes wrong in head injury • As ICP  and approaches MAP, cerebral blood flow  • Results in  CPP • Compensatory mechanisms attempt to  MAP • As CPP , cerebral vasodilation occurs to  blood volume • This leads to further  ICP,  CPP and so on