Pediatric Neurosurgery

Head Injury

• Introduction
• Incidence
• Types of Head Injury
• Current Knowledge & Management
• Long-term Sequellae
• Prevention

INTRODUCTION

• Motor vehicle crashes #1 cause of TBI, SCI, and seizures
• 600-700 children die each year
• 75,000 children are injured

INCIDENCE

• Trauma is the leading cause of death in children.
• 11,000 children die from trauma annually
• Of those, >80% had a severe head injury
• In children ages 1-15, more died from trauma than all other causes…COMBINED

CSF DRAINAGE VS ICP MONITORING

• Therapeutic vs. Diagnostic
• Hydrocephalus vs. Elevated ICP
• Infection vs. CSF Diversion
• Acute vs. Chronic

SECONDARY INJURY FIRST TIER THERAPIES

• Hypoxia
• Hypotension
• Hypocapnea
• Late Bleed
• Increased Intra-cranial Pressure

HYPOXIA

• Requires emergent intubation
• However, person intubating must be cognizant that there is a 5% incidence of cervical spine injury
• Too much oxygen is impossible in the acute phase
• Minimize PEEP to minimize afterload

HYPOTENSION

• Concern in reduced CPP
• CPP>60 required in adults
• Children may well tolerate >50mmHg
• Fluid resuscitation is cornerstone in trauma
• CPP = MAP - ICP

HYPOCAPNEA

• Optimal pCO2 = 25-35
• >35 causes vasodilation and increases ICP
• <25 causes vasoconstriction and increases the incidence of cerebral ischemia from 29% to 73% as measured by Xenon CT

LATE BLEED

• Abrupt increase in intracranial pressure,
  • unrelated to external influences,
  • poorly responsive to usual measure
• Requires head CT
• Treatment is surgical

INCREASED INTRACRANIAL PRESSURE

• Paralysis, sedation, intubation
• CSF Drainage
• Mannitol (0.5-1g/kg IV)
• Hyperventilate to pCO2 25-30

SECONDARY INJURY SECOND TIER THERAPIES

• Hypertension
• Hypothermia
• Barbiturate coma
• Decompressive craniectomy
• Reducing blood viscosity
• Reducing Hyperexcitation

HYPERTENSION

• If CVP normal, next step is Phenylephrine or Dopamine
• Goal is CPP>50mmHg
• CPP=MAP-ICP-CVP

HYPOTHERMIA

• Initially suggested by Phelps in 1897
• Mild Hypothermia to 32-34 0C
• Lower causes coagulopathy
• 5-10% CMRO2 change per 0 C
• Hyperthermia injures BBB

BARBITURATE COMA

• Decrease CMRO2 and CNS lactate and glutamate
• EEG burst suppression or levels
• Survival, but poor outcome
• Arterial hypotension common
• Recent success in small series

REDUCING BLOOD VISCOSITY

• Mannitol reduces blood viscosity. Concern re renal damage with serum osmolarity >320
• Hypertonic saline can also be used to increase serum sodium, which artefactually drops with Mannitol
• Albumin and urea are infrequently used

REDUCING HYPEREXCITATION

• Felt to be significant cause of secondary injury due to increased metabolism without compensatory increased CBF
• Glutamate antagonists
• GABA agonists
• Oxygen radical scavengers

1. Ong et al, Pediatric Neurosurg;(1996 Jun) v24 p285-91

CT FINDINGS IN N.A.T.

• Interhemispheric falx hemorrhage
• Sub-dural hemorrhage
• Large, non-acute extra-axial fluid collection
• Basal ganglia edema
• p<0.05 for above per Hymel et al, Pediatr Radiol; (1997 Sep) v27 n9 p743-7.

SEIZURES

• Increase CBF and ICP
• Higher incidence with lower GCS
• 20% if cerebral contusion
• Immediate seizures not recurrent
• Prophylactic anticonvulsant use
• Treat for 7-10 days

SEQUELLAE

• Cognitive
• Higher level comprehension
• Motor
• Fine motor usually more involved