Mechanisms of coup and contrecoup injury during trauma to the brain

Mechanisms of coup and
contrecoup injury during
trauma to the brain
Andrew McLaughlin
Whiplash
• https://www.youtube.com/watch?v=Vqlkpt9d89g
• Brain is seen to make contact with skull, leading to injury
• Sudden acceleration or deceleration responsible
• Different than if skull contacts an object
Definition of Terms
Coup Injury
Contrecoup Injury
• Occurs during blow to
the head
• Occurs during blow to
the head
• Site of initial impact
• Site opposite the initial
impact
• Likely caused by skull
inbending or fracture
• Many theories for
mechanism
Review of Skull/Brain Interface
• Skull is a relatively hard, bony interface
• Meninges protect the brain from direct contact
• Dura Mater
• Arachnoid – subarachnoid space contains CSF, blood vessels
• Pia Mater
Coup Injury
• Depression of the skull impacts brain
(clear mechanism)
• Typically seen when stationary skull
is struck by a moving object
• Focal injuries usually resulting in
cerebral contusion/hemorrhage
Contrecoup Injury
• Mechanism is far less easily understood
• Widely recognized as having greater severity
• Often seen when moving skull impacts an immovable/external
object
• Similarly results in focal injury and cerebral
contusion/hemorrhage
Theories for Contrecoup Injury
• Positive Pressure Theory
• Rotational Shear Stress Theory
• Angular Acceleration Theory
• CSF Displacement Theory
• Negative Pressure (Cavitation) Theory
Positive Pressure Theory
• During movement, the brain lags at the back of the skull while
the CSF pools near the front (lessening coup injury)
• Upon impact, compressive waves transmit across the brain
and cause it to press against the back of the skull
• Problems: CSF is more dense than brain, meninges would stop
brain from migrating towards the back
Rotational Shear Stress Theory
• Takes into account non-linear forces, significant rotational
movement during traumatic injury
• Combination of rotational and linear movements cause stress
to tear wherever it is greatest
• Problems: does not explain contrecoup, injuries likely from
irregular bone
Angular Acceleration Theory
• During angular acceleration, objects attached to another
accelerate more slowly
• Similar to positive pressure theory, specifically explains injury
to frontal lobe when falling backwards
• Brain accelerates more slowly than skull and is pushed up
against frontal portion
• Problems: does not explain linear contrecoup injuries,
meninges would counter most differences in acceleration, CSF
is more dense
CSF Displacement Theory
• One of the most recent theories, based on fact that CSF is
more dense than the brain
• Upon sudden deceleration, the CSF displaces the brain
backwards so initial contact will be with contrecoup surface
• In falling backwards, the initial contact will be with narrow,
irregular surface and involve a small surface area of the brain
• Problems: CSF composes only 150mL of volume, does not take
lateral/angular movement into account
2004 CSF Displacement
•
•
•
•
Paper by Drew and Drew, Neurocritical Care
Modeled brain and CSF off balloon in water
First picture immediately before impact, second 1 sec. after
Shows initial movement is in the backwards direction
Negative Pressure Theory
• Also known as the cavitation theory, generally most popular in
nature
• Upon sudden deceleration, the brain moves forward creating
tensile stress through negative pressure at the contrecoup site
• The cavitation of the brain pulls apart the contrecoup area
• Problems: CSF is more dense and would move forwards first
2012 Cavitation Study
• Goeller et al, Journal of Neurotrauma
• Modeled brain using sophisticated polycarbonate ellipsoid
• Filled ellipsoid with degassed water for CSF and Sylard gel for
brain tissue
• Recorded pressure in the CSF and skull deformation
• Results indicated cavitation as a likely cause of damage
Best Candidate?
• Positive pressure, rotational shear stress, and angular
acceleration theories seem either inaccurate or incomplete
• 2004 study suggests rudimentary evidence for CSF
displacement theory
• 2012 study implies cavitation theory most likely
Occurrence of Contrecoup Injury
• 2012 study used as a model of the effect of a blast wave from
an improvised explosive device (IED)
• 2014 Case Study (Sato et al., Legal Medicine)
• 54 y.o. alcoholic woman found dead from traumatic basal
subarachnoid hemorrhage (TBSAH)
• Fell and bruised left posterior parietal region, but the
hemorrhage appears to have been most serious in right
cerebellum
• Cerebellum usually tightly packed into posterior fossa, alcoholism
led to atrophy (assessed by Purkinje cell loss and stumbling gait)
allowing for increased movement and resulting contrecoup injury
• Proposed as the first recorded instance of contrecoup TBSAH
Subarachnoid Hematoma (notice arteries still intact)
(A) Right cerebellar contusion (arrows) (B) Histological exam shows tissue damage
References
• Images
• Types of Neurologic Damage
http://www.northeastern.edu/nutraumaticbraininjury/what-is-tbi/types-ofdamage/ (accessed Apr 17, 2015).
• medicallegalart. Coup-Contrecoup Injury. YouTube, 2011.
• Brain Anatomy http://www.mayfieldclinic.com/PE-AnatBrain.htm#.VTEFXvnF-PU
(accessed Apr 17, 2015).
• Meninges Catalog
http://vanat.cvm.umn.edu/neurHistAtls/cataPages/cataMen.html (accessed Apr
17, 2015).
• Ways the Brain is Injured http://www.braininjury.com/injured.shtml (accessed Apr
17, 2015).
• Journal Articles
• Bhateja, A.; Shukla, D.; Devi, I. B.; Kolluri, V. S. The Indian Journal of Neurotrauma
2009, 6 (2), 115–118.
• Drew, L. B.; Drew, W. E. Neurocritical Care 2004, 1 (3), 385–390.
• Goeller, J.; Wardlaw, A.; Treichler, D.; O’Bruba, J.; Weiss, G. Journal of
Neurotrauma 2012, 29 (10), 1970–1981.
• Jin, X.; Mao, H.; Yang, K. H.; King, A. I. Annals of Biomedical Engineering 2014, 42
(4), 812–821.
• Goggio, A. F. Journal of Neurology, Neurosurgery & Psychiatry 1941, 4 (1), 11–22.
• Sato, T.; Tsuboi, K.; Nomura, M.; Iwata, M.; Abe, S.; Tamura, A.; Tsuchihashi, H.;
Nishio, H.; Suzuki, K. Legal Medicine 2014, 16 (2), 92–94.
Questions? Comments?