The Importance of Trauma in Traumatic Brain Injury

The Injury Event Dictates Injury Outcome

Bryan Pfister, PhDProfessor and Chair, Biomedical Engineering

Associate Director, Center for Injury Biomechanics, Materials and Medicine

Namas Chandra, DirectorBryan Pfister, Assoc. Director

Thanks to colleagues/students and funding agenciesThanks to millions of soldiers who guard our freedom

In Vitro Model – Stretch InjuryShock Tubes - Blast Injury

Drop Tower- Blunt InjuryAnimal Models

Unique Facilities

Peak

Rise time

Traumatic Brain Injury

Blunt Injury

Inertial LoadingDiffuse Injury

BlastInjury

Margulies et. al. 1990

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Mechanics of TBI• Head rotations lead

to significant shear deformations of brain tissue.

• Bulk shearing often translates to a localized stretching of individual neurons and their processes.

Magou et.al. 2011 J NeurotraumaSmith and Meaney 2000 NeuroscientistMeaney et.al. 1995 J Neurotrauma

DAIDiffuse Axonal Injury

Widespread injuryto axons.

Stretch leads to cellular damage.

Traumatic Axonal Stretch Injury

mTBIRepair

orDysfunction?Smith and Meaney 2000 Neuroscientist

In Vitro TBI Model Traumatic Axonal Stretch Injury

Magou et.al. 2011 J Neurotrauma

What type of loading and tissue deformation is realistic?

Concussion / Blunt Head Injury Modeling

Human Scale Model

(PMHS)

Impactor• Interchangeable body• Variable impact speed 3mph 5mph

Skull-Brain-Neck Surrogate• PVC human skull• 20% ballistic gel with markers• Hybrid III anthropomorphic neck• Adjustable impact orientation Crown Front

Blunt Injury Experimental Setup

Impact Direction Affects Deformation

Analysis: Motion tracking and strain computations

Shear strain - 3mph impact

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ε1 ε2 γmax

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Contour maps of mean maximum strains

Contour maps of strain rates associated with maximum strainsData displayed is for 5mph impacts

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ε1 ε2 γmax. . .

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Different Rates of Deformation

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Modeling Variations in Injury

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Credits

Grant SupportNIH-NINDS

National Science FoundationNew Jersey Commission on Brain injury Research

In vitro modeling:Joshua Berlin

------Alexandra Adams

George ‘Dino’ Magou

In vivo modeling:Viji Santhakumar

Kevin Pang------

Mathew LongAswati ArvindEric Neuberger

Human surrogate modeling:Abdus Ali

Michael HannaBrian Swenson

Blast Injury:Namas ChandraMaciej Skotak

Rama Rao