Dynamic Biomechanical Findings on Shaken Baby Syndrome/Lethal Minor Falls
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FROM: Injury Biomechanics Researcher: Chris Van Ee, PhD
TO: The Honorable Court
SUBJECT: Dynamic Biomechanical Findings on SBS-LMF
DATE: March 3, 2008
1. Accepted Findings Will Assist Court:
The purpose of this document is to assist the Court with its understanding of
two injury causation mechanisms that have caused significant disputes within the
medico- legal communities.
These injury mechanisms are SBS (Shaken Baby Syndrome) and LMF (lethal [-6’]
minor falls with severe head impact). Impact and injury biomechanics is the
study of the mechanics of how injury occurs. In that respect, biomechanics is in
a unique position to aid in the understanding of how falls or shaking can result
in serious or fatal head injury.
While many in the medico- legal communities have debated these injury causation
mechanisms, the Court is advised that most medical doctors are not trained in
our scientific discipline and do not access our databases nor study our
peer-reviewed research.
Indeed, as our findings show, there is no credible debate in our discipline over
certain Inconvenient Truths”, truths that some have ignored or distorted.
This is not to say that all the answers are in, for they most assuredly are not.
There is a great deal of study ongoing regarding the understanding of infant and
adolescent head injury. However, the studies to date have allowed for great
advances in the understanding of head injury and the development of state of the
art safety devices and interventions. Indeed their success is predicated on an
accurate understanding of head injury. Some of the applications of the work of
injury biomechanics include automotive child safety seats, helmets, advanced
airbags, playground surface materials, and crib design. In the development of
products or safety interventions it is important to understand how injury takes
place and identify the governing factors. The intervention can then be designed
to affect the governing factors as to eliminate or mitigate the resulting
injury. Based on the reliable scientific data that is currently available and
used for the understanding of pediatric head injury in other applications the
following statements can be made.
Dynamic Biomechanical Findings March 7, 2008 Page 2 of 4
2. SBS/LMF Findings From Biomechanical Tests and Studies:
(A) Scientific testing has shown that head acceleration levels from
anterior/posterior human shaking of a normal 0- to 2-year-old child in the
sagittal plane results in head acceleration and force levels that are much lower
than those which are associated with traumatic head injury. Repeated testing of
this hypothetical has shown that the head accelerations associated with shaking
are far below the level associated with injury and there is no quality data to
support the SBS brain injury mechanism. Thus shaking, even if done in a fit of
anger, is not expected to result in head dynamics sufficient to cause direct
intracerebral trauma.
(B) Human shaking (id.) may cause lethal brain stem and cervical spine injuries
in a 0-to 2-year-old child, as the forces necessary for these injuries are well
below the level needed for fatal brain injuries and are consistent with the
forces that can be produced in shaking. Put another way, these neck injuries
would be expected in any hypothetical-superhuman-strength case of SBS where
superhuman dynamics resulted in head accelerations leading to intercerebral
trauma (if SBS were valid, which it is not).
(C) If a 0- to 2-year-old child accidentally falls from a height of six feet and
impacts head- first on a hard sur face such as carpeted cement, the sudden
impact has the potential to generate sufficient head accelerations to cause
fatal intracerebral injuries. Whether any given fall is fatal depends on a host
of variables and the fall mechanics which are different in each accident, but
the potential head dynamics that result from a 6 foot high fall could far exceed
the tolerance associated with fatal head injury.
(D) Intentionally impacting a 0- to 2-year-old child’s head against a hard
surface could easily cause fatal brain injuries that would mimic those of a fall
and today’s science cannot distinguish accidental from non-accidental impacts of
falls of similar magnitude, barring extraordinary signs, e.g., grip marks or
eye-witness accounts.
(E) The foregoing findings are based on principles universally accepted within
my field and concern scientific subject matters that I am willing to testify on
in this case. The findings are overwhelmingly supported by the following
reference list of biomechanical tests and studies.
3. References of Scientific Validation:
(A) Duncan M. Laboratory note: On the tensile strength of the fresh adult
foetus. BMJ 1874;2:763–764.
(B) Ommaya AK, Faas F, Yarnell P. Whiplash injury brain damage. JAMA 204
1968;285-289.
(C) Ommaya AK, Yarnell P. Subdural hematoma after whiplash injury. Lancet
1969;257.
Dynamic Biomechanical Findings March 7, 2008 Page 3 of 4
(D) Mertz HJ, Patrick LM. Strength and response of the human neck. In: Proc of
the 15th Stapp Car Crash Conference; Warrendale, PA; Society of Automotive
Engineers 1971; SAE paper #710855:2903–28.
(E) Mohan D, Bowman BM, Snyder RG, et al. A biomechanical analysis of head
impact injuries to children. J Biom Engng 1979;101:250-260.
(F) Stürtz G. Biomechanical data of children. In: Proc. 24th Stapp Car Crash
Conference; Warrendale, PA; Society of Automotive Engineers 1980; SAE paper
#801313:525-59.
(G) Stürtz G. Correlation of dummy- loadings with real injuries of children by
repetition tests. In: Proc. Vth International IRCOBI Conference; Bron, France;
IRCOBI 1986:121-131.
(H) Weber W. Experimental studies of skull fractures in infants. Z Rechtsmed
1984; 92:87–94.
(I) Weber W. Biomechanical fragility of the infant skull. Z Rechtsmed
1985;94:93– 101.
(J) Duhaime A-C, Gennarelli TA, Thibault LE, Bruce DA, Margulies SS, Wiser R.
The shaken baby syndrome: a clinical, pathological and biomechanical study. J
Neurosurg 1987;66:409-15.
(K) Melvin JW, Injury Assessment Reference Values for the CRABI 6-Month Infant
Dummy in a Rear-Facing Infant Restraint with Airbag Deployment. SAE Paper #
950872, 1995.
(L) Irwin AL, Mertz HJ. Biomechanical Bases for the Crabi and Hybrid III Child
Dummies, SAE Paper # 973317.
(M) Tylko S, D Dalmotas. Assessment if Injury Risk to Children from Side
Airbags, 44th Stapp Car Crash Conference, 2000-01-SC02.
(N) Margulies SS, Thibault KL. Infant skull and suture properties: measurements
and implications for mechanisms of pediatric head injury. J Biom Eng 2000;122:
364-371.
(O) Accidental Injury, Alan M. Nahum (Editor), John Melvin (Editor), Springer
Verlag; 2nd edition, ISBN: 0387988203, 2001.
(P) Hagedorn AV, Rhule DA Daniel A. Rhule, Child injury tolerance through case
reconstruction, International Technical Conference on the Enhanced Safety of
Vehicles, 2001-06-0026.
(Q) Prange MT, Coats B, Raghupathi R, et al. Rotational loads during inflicted
and accidental infant head injury. J Neurotr 2001; Abst. D8;18:1142. Dynamic
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(R) Plunkett J. Fatal pediatric head injuries caused by short distance falls. Am
J Forens Med Pathol. 2001;22:1-12. (included due biom. Reconstruction of
videotape accident).
(S) Ommaya AK, Goldsmith W, Thibault LE. Biomechanics and neuropathology of
adult and paediatric head injury. Br J Neurosurg 2002;16-220-42.
(T) Klinich, K. D.; Hulbert, G. M.; Schneider, L. W. 2002. Estimating infant
head injury criteria and impact response using crash reconstruction and finite
element modeling. Stapp Car Crash Journal, Vol. 46, SAE Paper #2002-22-0009.
(U) Prange MT, Coats B, Duhaime A-C, Margulies SS. Anthropomorphic simulations
of falls, shakes, and inflicted impacts in infants. J Neurosurg 2003; 99:143-50
(V) Prange MT, Luck JF, Dibb A, Van Ee CA, Nightingale RW, Myers BS. 2004.
Mechanical properties and anthropometry of the human infant head.. Stapp car
crash journal. Vol. 48
(W) Goldsmith W, Plunkett J. A biomechanical analysis of the causes of traumatic
brain injury in infants and children. Am J Forens Med Pathol 2004;25:89-100. (X)
2005, NPSC, Fall surfaces tests.
(Y) Bandak FA. Shaken baby syndrome: a biomechanics analysis of injury
mechanisms. Forens Sci Int 2005;151:71-79, including comments in
2006:164,278–279.
(Z) Prange M, Newberry W, Moore T, Peterson D, Smyth B, Corrigan C. Inertial
neck injuries in children involved in frontal collisions. SAE 2007 World
Congress; Warrendale, PA; Society of Automotive Engineers; SAE paper
#2007011170.
(AA) Monson K, Sparrey C, Cheng L, Van Ee C, Manley G. Head exposure levels in
pediatric falls. NNS 2007; abstract.
By: ___________________Chris Van Ee, PhD