Upload
hadung
View
219
Download
0
Embed Size (px)
Citation preview
HEAD AND SPINAL INJURY TOLERANCE WITH NO DIRECT HEAD IMPACT
By
A. K. Ommaya, M . D . , F . R . C . S . and L. Thibault
This paper reviews the s tate of the art concerning tolerance for
injury to the central nervous sys tem when the head is not directly s truck.
Progress in this area of the biokinetics of impact has been hampered by
the diff iculty of sustained collaborative work in the three f ields which
must be coordinated in order to achieve adequate reliability o f data ;
namely, mathemat ical mode l s , experimental work with physical and animal
models and predictive val idation from human accident data .
After reviewing the four analytic models currently availab l e , this
paper wil l summarize the current knowledge concerning the o ther two areas
mentioned with special reference to experimental work conducted by the
author a t the National Inst itutes of Health.
M athema tical Mod e l s
1 . ADVANI . This mod e l i s of an elastic spherical she l l with a low
modulus elastic/visco-elastic core , subj ected to three types of loading :
1 . axisymmetric translational impact
2 . symmetric torsional impact
3 . whiplash type loading
The model drives numerical s o lutions for limiting desplacements , shear ,
and normal s tresses .
2 . HAYASHI . This i s a two dimensional model , consisting of elastic-
ally connected concentric r igid body cylinder s . The loading i s in the
sagittal p lane symmetry with angular acceleracion v s . t ime for the real
3 1 1
, , S ituation replaced by pulse wave eMAX for equivalent time duration tD .
The model derives resul tant shear Stress vs . eMAX tD and uses the
,
constitut ive relations to determine the critical level s for inj ury . The
data derived from this model was compared to our experimental data with
reasonabl e correspondence.
3. JOSEPH AND CRI SP . This model is of a spheroidal brain-skull
body having the mathema tical relat ionship x2 + 7 The loading used in this model was a cons tant angular velocity i . e . , a
s t eady rotational motion about any of 3 mutually orthogonal axe s . The
model derives expressions for mechanical s tresses , s trains and disp lace-
ments of the brain and uses the constitutive relations developed by
the data from the work of Galford and McElhaney.
4 . BYCROFT . This model is of the skull as a rigid spherical she l l
and of the brain a s a s impl e elastic solid . The loading is a full sine
and half-sine angular acceleration in the axisymmetric plane and it
derives expres s ions for shear s tress as a complex function of time and
radial posi tion in the mod e l . Holburn ' s sca l ing law is used and compared
to data obta ined from some of this authors experimenta l work
Experimental Work in the Rhesus Animal Mode l .
Two hypotheses which have s t imulated considerable research in the
field of head inj uries are a ssociated with the name of Holbourn and
Gurdj ian. Based on experiments with gelatin models of the brain
Holbourn believed that rotational components of inert ia l loading of
the head was the mos t s ignificant cause of diffuse effects on the
brain (e . g . cerebral concussion and contrecoup lesions ) . He dis
counted translational component s of inertia l loading claiming that the
resultant compre s s ion or rarefaction of the brain would not be s igni
ficantly inj uriou s . ( l , 2 ) Gurdj ian correctly pointed out that this
analysis neglected the effect o f the foramen magnum and the work of
this inves t igator and his colleagues over the past 25 years a t Wayne
S tate University has formed the basis o f the current standard tolerance
curve for head injury used by design engineers the world ove r . ( 3 , 4 )
Because this curve i s expressed i n terms o f translational acceleration
only it was impor tant to determine experimentally the precise individual
contribution of both translation and ro tation to the injury potential of
inert ial loading of the brain. Both hypothesi s accept that the contact
phenomena of impac t are the main cause of focal lesions at or near the
site of impact but differ on the relative s ignificance of the transla tional
and rotational component of inertial loading caused by impact . Our earlier
work had shown that pure inert ial loading produced by experimental whiplash
could produce cerebral concussion and surface haemorrhages of the brain
(primarily subarachnoid and subdural b leeding ) . < 5 , 6 ) Although the traumatic
unconsciousness thus produced by a combination o f head rotation and trans
la tion without direct impact was identical to that seen after head impac t ,
the l esions found in the brain differed in the two types o f inj ury . This
difference was primarily due to the presence of cerebral contusions , no t
explicable solely by the contact phenomena of impact . ( 7 )
This part o f the paper presents our current data obtained b y two new
techniques ; firstly the use of a special head holding device has a llowed us
to compare for the first time the inj urious effects of pure translational
3 1 3
acceleration of the head with head rotation at equivalent level s of input
acceleration and without the complicating effect of impact contac t
phenomena . (See Figure 1) Secondly, we have developed the somatosensory
evoked response (SER) as an in-vivo index of the onset and duration of
traumatic uncons c iousnes s and development of brain lesions . (See Figure 2)
We have evidence that cerebral concussion and diffuse lesions in the brain
are caused primarily by the rotational component of inertial loading while
cortical contusions , intracerebral haematomas and s imilar focal lesions
are primarily due to translation . (See Figure 3 ) At the levels of
acceleration tested , cerebral concussion was invariably produced by rotation
but no t by translation of the head . ( B , 9 ) These data will b e presented and
d iscussed . Implications of these data .
1 . The standard tolerance curve for head injury wil l have to be modified
to take into account the role of rotation .
2 . With this model for clo sed head injury it is pos s ible to test hypotheses
for head inj ury mechanisms with precision and ease .
3 . lt i s now possible to analyse the c l inical phenomena of head inj ury (coma ,
amnesia and post-traumat ic sequelae) in a reproducible primate mode l .
4 . Our work to date makes i t poss ible to re-define cerebral concuss ion in a
way such that the clinical and experimental data are reconciled . This
hypothes i s will be discussed .
5 . The technique o f SER recording i s directly applicable to man for the
development of an ' on-line ' in-vivo index of severity of head injury a s
well a s a research tool to unravel the mechanisms of neural trauma in
the human .
Results With A Phys ical Model Using The Technique Of Moire Analysi s O f Strain.
In collaboration with Dr . A. J . Durelli o f Catholic University , we are
currently performing experiments on four hal f skull s o f the squirrel monkey ,
rhesus monkey , chimpanzee and the human . These half sku l l s are f illed with
a s ilicon material with physical properties approaching that of brain on
which a grating has been printed and the entire surface i s covered with a
lexan plate . These models are subj ected to linear and rotational acceler
ations and the Moire pat terns of the resulant deformation are analyized to
determine the relative displacement o f points in the plane o f symmetry of
the brain mode l . This wil l be the f ir s t s tep in the determinat ion o f
strains , velocities , and accelerations t o which each point is subj ected in
the proce s s of indirect impac t . Prel iminary resul t s of these experiments
sha l l also be reviewed in this paper . Finally the paper wil l at tempt to
correlate the available human injury data in this type of injury s ituation
with the current available data from the models and possible directions
for future work will be outlined .
3 1 5
Trans
lation
R
ota
tio
n
Arm
�
An
imo
! R
es
tro
int
/ C
ho
ir
\
HE
AD
A
CC
EL
ER
AT
ING
D
EV
ICE
Link
age
1
Fi
gu
re
1
11--'.
Solen
oid
1 1 1.>
-1
Com
Prof
i :e
......,.
Disk
Brake
-.
..... E l
ec tri
c Mo
tor
a S
pe
ed
C
on
tro
l
S R - ! O
CONCUSSION O�JLY N O LES!O\ CONTRALATERAL MEDiAL E�ECTRCDE
---1 6 4 1:.sec
MINUTES
220
60
5 1
25
20
1 8
1 6
1 4
1 1
9
8
7
6
5
4
3
2
PRE I M PACT
�---
1 2 5 5 :i' S 2 :
F i gu r e 2
SL- 1 1
NO CONCUSS!O�·J ;.JQ L.C.SiO� RIGHT ��E01,'.;N ;.;c.; v E Si . '.\JL.4TION
LEFT LATERAL ELECTRODE
MINUTES
60
45
35
25
20 �V J\
1 5 -� �V /\ 12 �V
9
5
3 v� 2 �
PRE IMPACT
�
CONTROL �
� 500 UV �--
6 4 msec
3 1 7
Key ._
Sub
du
rol
blo
od
•••
••
• S
ubo
roch
noid
blo
od
�� Co
rtic
ol
cont
usio
n
"„
• •
Pe
tech
iol
hem
orr
hog
e
·[D�
�
-
' '
c���
A �
i���·
·� ''-
.,,,---
· -... /)
\-'0:�
- z� 7
\�j�J�
l�/
�
l 0
b
c
TRAN
SLATE
D b�
�l7�
. „..,_
�/f"
_,,/ �
--
Fi
gu
re
3
Num
be
r in
dic
ote
s lr
eq
uenc
y o
l o
ccur
renc
e �-
..-- _
_ __.-
--@
90
-100
7.o
l o
nim
ols
4
- �-- --, \
0
75-9
0/.
�-
. • �,,(,Y
:_ .. 0
50-75
7. , __
. �
(])
le"
tho
" 50t
Mid
hoo • •"'�
1 RO
TATED
�·�
-.
..:__.:...::..;/
��
;(
f
c K-
- ���::;;:
� .
,._ ...
. . ..
...... �"'
'z. „,,,..-
... : -..
...... -·�
.......
r' •• • ./'
\ ' ;
) ." ��
'/
/ c �
t 1
"-\
f�[":��;J
� ��:'
r'·'�f1'/
-. -••• .1
'• • ..
....----' 2
'
2 '
\&�)
f
� ....... �·-1·;��
:" .
;�.>'-, „ „
... · "' � .
. �-
�
Xi�) ----(i )
. .
;��->
1 " .
•
��r �·f+�
' )" ;-_·�
{ , �'
";•
, .„'.·
) �-
,;.,
.„
4)
•. " :.
./" --
. �
. .,.
· �.;�
.... „.<.
_ „.
d ,... ..
.. ,...... �··
··i ; ... ·„
... ···
�
,./; „;„•
" ) : 1
• „ . .....
\ ,�
· / .,.
..-:. . !
t ••
-,,, ____
\• ..
. 1· „
.. .,
• "I
. ' .--
7 !-<( -•
--\;
t(,.. �
�
'.
(-.. ,.1
, �
C:::-) _ C
-'
• �
·-=-
"' /
... .. '
�··
, h ,„(
) ',
„�·;i
:-
--\
' \
1 ' 1
{ ) (
� . „
,...--
•
1 jA
. . .i'
\ ... „�
i <
V �
' ,
, -
.. \
\ ("-A.Z.
j \
u.}'-i
/ :
· „ ---
, -
\ -:: , l
l: �
--#
·-
· 2
··� •• -...... •
f (c
J"t9..U
.ü
�� �'"' „ �
\' )t 1
.·rj·..,�
.
'\•, „ � · JR.\t:fj
� •
v<: :.-.
..�--:> l
l: )·
.' u;.�
4. • 2.
,
· .. ·' �
�
�:._„.
•·
Bibl iography
1 . Advani , S . H . , Owings , R . P . and Schuck, L . Z . : Response Evaluation of Translational and Rotational Head Injury Models . Shock and Vibration Digest . October , 1 9 7 2
2 . Hayashi , Tsuyoshi . Brain Shear Theory of Head Injury due to Rotat ional Impac t . Journal of the Faculty of Engineering. U. Tokyo . (B) . Val . 3 0 , No . 4 . 1 9 7 0 .
3 . Joseph, P . D . and Crisp , J .D . C . : On the evaluation of Mechanical Stresses in the Human Brain while in motion . Brain Research . Val . 26 15-3 5 , 1 9 7 2 .
4 . Bycrof t , G . N . : Acceleration .
Mathematical Model of a Head subj ected to Angular In press (Journal o f Biomechanics) .
5 . Holbourn, A . H . S . : Mechanics o f Head Injuries . Lancet 2 : 438 . 1943 .
6 . Holbourn , A . H . S . : Mechanics of Brain Inj ur ie s . British Medical Bulletin 3 : 1 4 7 , 1 945 .
7 . Gurdj ian , E . S . , Lissner , H . R . , Hodgson, V . R . et a l : Mechanisms of Head Inj ury . Clinical Neurosurgery 12 : 1 1 2 , 1966 .
8 . Gurdj ian, E . S . , Rober t s , V . L . and Thomas , L .M . : Tolerance curves of acceleration and intracranial pressure and protec tive index in experimental head inj ury . Journal Trauma 6 : 600-604 , 1966 .
9 . Ommaya , A . K . , Hirsch, A . E . and Martinez , J . : The role of "whiplash" in cerebral concussion. Proceedings of lOth S tapp Car Crash Conferenc e , 197-203 , 1966 .
1 0 . Ommaya , A . K . , Faas , F . and Yarne l l , P . : Whiplash injury and brain damage : An experimental study . JAMA 204 : 285-28 9 , 1968 .
1 1 . Ommaya , A . K . , Brugg , R . L . and Naumann, R . A . : Coup and contre-coup inJ ury : observations on the mechanics of visible brain injuries in the rhesus monkey . J . Neurosurgery 35 : 503-516 , 1971 .
1 2 . Gennare l li , T . , Thibaul t , L . and Ommaya , A . K . : Comparison of translational and rotational head motions in experimental cerebral concussion . Proceedings of 15th Stapp Car Crash Conference , 797-803, 1 9 71 .
13 . Gennarell i , T . , Thibault , L . and Ommaya , A . K . : Pathophysiologie responses to rotat ional and translational acceleration of the head . Proceedings of 16th S tapp Car Crash Conferenc e , 296-308 , 1972 .
14 . Ommaya , A . K . et al : Traumatic unconsciousne s s : Mechanisms of Brain Injury in violent shaking of the head . Proceedings American Assoc . Neurological Surgeons . Paper No . 3 6 , 1973 .
3 1 9