HUMAN BLAST TBI IS TOO HETEROGENEOUS FOR ONE ANIMAL MODEL

1. Human Severe Blast TBI is
Too Heterogenous for One
Animal Model
Col Rocco A. Armonda, MD
National Capital Neurosurgery Consortium
Walter Reed Military Medical Center, Bethesda

3. Disclaimer/Disclosure
• The views expressed in this presentation are those of the
authors and do not reflect the official policy of the
Department of the Army, Navy, Department of Defense, or
U.S. Government.
• No Disclosures applicable to this presentation

4. Objective
• Delinate the Varied Patterns of Severe
Human Blast Injury
• Discuss the Prognosis of Severe Blast Injury
• Identify Mean of Improving our Models for
Predicting Injury/Outcome
• Introduce Bayseian Modeling as a Means to
improve our understanding of Human Blast
Injury

5. Gaining Wisdom...
" By three methods we may learn wisdom:
First, by reflection, which is noblest;
Second, by imitation, which is easiest; and
third by experience, which is the bitterest.
(Confucius)

6. ‘the road to Ruin...’
" There are three possible roads to ruin:
women, gambling and technology. The
most pleasant is with women, the
quickest is with gambling, but the surest
is with TECHNOLOGY! (Georges
Pompidou)

7. Bayes Theorem
• Initial Beliefs+ Recent Objective Data= New/
Improved Belief
• English Clergyman Thomas Bayes (18th Century)
• “The Theory That Would Not Die, How Bayes’
Rule Cracked the Enigma Code, Hunted Down
Russian Submarines and Emerged Triumphant
from Two Centuries of Controversy” by Sharon
McGrayne

8. Variables of Severe Human Blast Injury
• All Varies Depending on Characteristics of Explosion: Not one is alike!
• “Time, Distance, Shielding, Enclosures, Flying Fragments”
• Influence of Body Armour
• Protection/Amplification/Transmission of Energy Waves
• Effects of Terminal Ballistics on the Skull, Skull Base, Brain, and
Cerebrovasculature
• Influence of Associated Pulmonary, Extremity, Abdominal Injuries

9. Demographic
Characteris0cs
NEUROSURGERY
Consults:Severe
Head
Injury
513:357
Age
27
+
7.7
years
(18-­‐73)
Sex
(M:F)
350:7
Injury
Type
(CHI:PHI)
139:218
Mechanism:
207
Blast
17
GSW
123
Other
Branch
of
Service:
214
USA
8
USAF
75
USMC
7
USN

11. Initial CT Scan: IED Explosion <15 Minutes from
Injury Severe Cranial Base Injury

12. Immediate ICA Rupture Subsequent:"
Occlusion/Stroke

13. DELAYED PROBLEMS

17. Serial TCDs: Pre/Post
Angioplasty!
▲ ▲

20. Mechanisms
Primary Brain Injury"
Blunt
Penetrating (bullets and fragments)
Combination- Blast (overpressure, direct strike, fragments, acceleration/
deceleration injury)
Secondary Brain Injury"
Hypotension (SBP<90), doubles mortality
Hypoxia (PaO2<60)
Intracranial Hypertension (ICH)
Ischemia (blood flow)
Herniation (tissue damage)

23. Not as SIMPLE!
• Blast Injuries Flying Fragments, Blunt force trauma, Fragmented Bone...

27. Pseudoaneurysm from
Bone Fragments

28. Small Fragments Big
Injury

29. IED Explosions

30. Immediate CT:
What Lies Beneath?

31. Terminal Ballistics of Severe Blast Injury In
Humans:
Observations
• Edema is Diffuse
• Onset of Edema is Late
• Length of Increased ICP is PROLONGED!
• High Association with Delayed Cerebral-Vasospasm.
• Outcome is difficult to predict!!!!!!

34. Predicting Patient OUTCOME
• Poor Characteristics
• Associated Large Vessel Infarction: Defines Disability
• Penetration of Fragments/Injury Zone into Diencephalon: Defines Level of
Independent Recovery
• Multiple Lobes Involvement/Bihemisphere/Combined Infra/Supra tentorial
involvement: Survival/Long Term Independenence
• Severe Concomittant Pulmonary Dysfunction MAJOR MORTALITY!

38. • Post-Injury #6
Day#6

39. Tests
• CT, EEG, TCDs, MRI...
(institution dependent?)
• Labs, CXR?
• Bladder Pressure?
• ICP Waveform?

40. ICP and Abdominal
Pressure
• Abdominal
Compartment
Syndrome
• Increased ICP
• Increased Bladder
Pressure
• Decreased Urine
Output

50. Severe Blast Injury with
Under-Armour Injury

54. PBI Spherical Bolt
Transbasal Penetration

58. Serial TCD Changes

59. IA Nicardipine/
Microangioplasty

60. Conclusions
• Each Patient/Injury is Different!
• Balancing the Brain vs Lungs for best overall
outcomes
• The Model Must Adapt to New Information:
BAYSEIAN THEORUM
• Prevention of Delayed Insults Occult Vascular
Injury (Vasospasm, Dissection, TICA) Improves
Outcomes.
• Predict Based on combined Model + Real-Time
Data (continual update!).