Whiplash injuries from a medical perspective
Dr. Wolfram Hell
LMU Ludwig Maximilians University MunichInstitute for Forensic Medicine
Medical-Biomechanical Accident Analysis MBU
Background: Grandfathers of dynamic seat testing: Dr. Markus Muser ETH-Zürich, Dr. Harald Zellmer Autoliv Germany with HIII, RID3, and BIORID
Estimated societal Costs of CSD Injury
seats approx. 54 CDN$/year)Canada: (cost reduction with better
Switzerland: >2 Mrd. SFR/year
Great Britain: 600-800 Million Pounds/year
Netherlands: 0.5 Billion Euro/year
Germany: 1-2 Mrd Euro/year (IFM-GDV)
Canada: costs per vehicle- occupant135 CDN$/year
USA: 10 Mrd. USD/year (IIHS)
only Rear-end vehicle accidents
Wealthy Countries with high compensation systems show very high economical loss (Swizerland, Norway, Canada)
Rising Incidence of CSD Injury
35
29,526,9
20,3
0
5
10
15
20
25
30
35
40
1969 1974 1980 1990
YEAR
%
calender year
traffic accidents, IFM-GDV German data material
CSD Injury risk per vehicle type and weight
Folksam
0 1 2 3 4 5
Volvo
DB 124
Opel Rekord
DB 190
VW Golf 1
Ford Fiesta
Injury Frequency
700 kg
800 kg
1200 kg
1200 kg
1400 kg
1400 kg
Injury Frequency
GDV VS90
0 0,5 1 1,5 2
Volvo
DB 124
Opel Rekord
DB 190
VW Golf 1
Ford Fiesta
Injury Frequency
700 kg
800 kg
1200 kg
1200 kg
1400 kg
1400 kg
Injury Frequency
source: IFM-GDV
weight factor and design factor
anatomy of the human spine structured bar
24 vertebra (7 cervical, 12 thoracic, 5 lumbar)
protection of the spinal cord
shock absorbing function for the brain
7 cervical vertebra
12 thoracic vertebra
5 lumbar vertebra
C1 - C7
T1 – T12
L1 – L5
cervical spine elements
upper Atlas and Axis (C1, C2)
middle C3 to C5
lower C6 to C7
most frequent site of injury and symptoms
Source:Sobota
Quebec Task Force- Results
• The initial diagnostics and documentation of CSD injuries is
insufficient
• Major Problem: different injury classification
• Lit. Analysis of 10.000 Publications shows, that only 400 can
withstand a critical View regarding Injury Definition and
Comparability
• Improved Medical Injury management (early detection and therapy
strategies for chronic cases) important
source: Spitzer et al, SPINE 1995
QTF Injury Severity
degree clinical signs
0NO subjective or objective symptoms of the Cervical Spine
1Cervical Spine Symptoms (subjective: pain, stiffness)
NO objective clinical signs
2Cervical Spine Symptoms ANDMUSCULO-SKELETTAL SIGNSMACROLESION
3Cervical Spine Symptoms AND
4
MICROLESION
NEUROLOGICAL SIGNSNEURAL DAMAGE / IRRITATION
Cervical Spine Symptoms ANDFRACTURE or DISLOCATION
Pathological correspondent, QTF
single or multiple (ultra-)microskopic lesionslesion is too small to cause muscular spasms
Distorsion and soft tissue bleedings (joint capsules,
ligaments, tendons and muscles)
Secundary muscle spasm after soft tissue injury
Injuries of the neural system
caused by traumatic injury or secondary due to
Irritation caused by bleeding and inflammation
QTF 1
QTF 2
QTF 3
MICROLESION
MACROLESION
NERVE CELL DAMAGE/ IRRITATION
QTF degree 1 and 2
muscular damage
• muscular sprain/tear
• healing within
days/weeks
• leaves scar, but no
permanent damage
source: Foreman, Croft, Whiplash Injuries
Williams & Wilkins, Baltimore, 1995
neck muscles
deep muscles of the cervical spine
might be primary site of injury
Musculus semispinalis capitis/cervicis and multifidus
Three stages of Nerval Injury
source: Foreman, Croft, Whiplash Injury
Williams & Wilkins, Baltimore, 1995
1
Neuropraxia
Local demyelinisation (neurons intact)
Complete recovery
2
Axonotmesis
Axons interrupted
Recovery complete or nearly complete
3
Neurotomesis
Axons and sheaths both interrupted
Recovery never complete
Suspected Pathology (Spine) I
• Zygapophysial joints
- synovial impingement
- hemarthrosis (a)
- joint capsule rupture/tear (b)
• Intervertebral disc
- tear of annulus fibrosus (c)
• Upper cervical ligaments
- tear of anterior ligament (d)
ac
b
d
Poorly seen in X-Ray and MRI
source : Barnsley, Lord, Bogduk, Clinical Review, Whiplash Injury, University of Newcastle,NSW, Australia 1994
Suspected Pathology (Spine) II
• Pressure gradient within spinal channel
- injury of nerve cells within spinal ganglia (e)
e space of cerebro-spinal fluid
spinal cord within spinal channel
QTF and gender
SOURCE: EU WHIPLASH 1 PROJECT – IFM-GDV
gender - QTF (dv > 10 km/h)
8
922
8
19
8369
92
69
49
44
0%
20%
40%
60%
80%
100%
male n=47 female n=45 male n=12 female n=26
QTF 3
QTF 2
QTF 1
QTF 0
driver N=92 passenger N=38
rear-end collisions
Visual Demonstration I
sled test (Clip) delta v 9,5 km/h
Injury mechanism at rear end collision
source: Felix Walz, modified
Phase 1
Translation and Extension
Phase 2
max Extension
Phase 3
Flexion Rebound
neck muscles during rear crash
sternocleidomastoid muscle and semispinalis capitis muscle show:
potential to influence kinematics and
to be primary site of injury due to excentric contraction
EMG during volunteer tests, dv 9,5 km/h
0
20
40
60
80
100
120
1 101 201 301 401
time [msec.]
EMG [mV]
-6
-4
-2
0
2
4
6
8
10A(h-T1) [g]Semi
Sterno
A(h-T1)
maximum Amplitude of sternocleidomastoid muscle during
head/head-restraint contact
afterwards rising activity of semispinalis capitis muscle reaching
Maximum at 200ms (Rebound Phase)
Arguments against dynamic seat test
• We do not know the injury exactly, so a test does not make much sense
• We also do also not know the exact lung cancer pathology, but nevertheless smoking is a serious risk factor
• Neck movement and forces are also significant risk factors
• If neck movement and forces are reduced,
CSD injury logically must also be reduced
Low Cost car seat
improved car seat
LAB test vs. Accidentiology
• Does the dynamic seat test really measure seat
performance ?
• Only real accident analysis can answer this: Seat test ranking should be comparable to real accident ranking. Serious basic research with high case numbers necessary
• Continuous monitoring important
Rear-End Impact Car Performance Statistics
SOURCE: IFM-GDV, statistics HuK Coburg Insurance 2000, damages
With injured Long-term injured > 6
weeks Manufacturer Rear end
collisions total n Per 1000 n Per 1000
rating
B- France 258 13 135 1 10 good
F- Germany 378 39 257 8 53
G- Germany 1087 115 294 25 64 medium
G - Germany 523 88 433 18 89 G- Germany 229 30 380 8 101 E- Germany 177 18 400 7 156 B- France 252 21 328 10 156
poor
Injury rates at rear-end collisions divided by manufacturer and type („Long Term Injuries“ more than 6 weeks
lower middle class vehicles
Rear-End Impact Car Performance Statistics
SOURCE: IFM-GDVSOURCE: IFM-GDV, statistics HuK Coburg Insurance 2000, damages
Injury rates at rear-end collisions divided by manufacturer and type „Long Term Injuries“ more than 6 weeks
With injured Long-term injured
> 6 weeks Manufacturer Weight class Rear end collisions
total n Per 1000 n Per 1000 rating
C- Germany Upper middle class 90 14 156 2 22
D- Germany Small car 65 16 246 2 31
E- Germany Upper middle class 80 18 225 3 38
good
F- Germany Middle class 112 20 179 6 54
G- Germany Middle class 52 12 231 3 58
H- Germany Upper middle class 173 35 202 11 64 D- Germany Middle class 211 44 209 14 66
medium
F- Germany Middle class 191 52 272 18 94 poor
CSD- Long-Term injury
if recovery takes more than 2 weeks for at least one passenger then for all
occupants with CSD:
in less than 70 days 50% will recover
in 25% recovery will take >6 months
in 8% chronic impairment
time to reach full recovery
n=253 persons in 208 cars
CSD and documented date of limit in earning capacity
days after rear-end accident and diagnosis
900
800
700
600
500
400
300
200
100
0
Ra
tio o
f pe
rso
ns
rea
ch
ing
full
reco
ve
ry
1,0
,9
,8
,7
,6
,5
,4
,3
,2
,10,0
function
censored
LONG TERM INJURIES SHOULD JUSTIFY HIGH PREVENTION EFFORTS
Source: W2 Long Term Injury Analysis LMU
time until reduction of earning capacity reaches 0%,all 253 CS-Patients in 208 rear-end impacts (at least one occupant with documented CSD injury suffering for more than 14 days)
Case example FATAL INJURY
Source: FS 90 IFM-GDV
seatback collapse after rear-end impact
Child behind driver was killed
Seatback collapse must be avoided
OOP Dummy
Out of Position (OOP) ΔV 9,5 km/h
OOP volunteer
comparison Dummy vs. volunteer (OOP)
50 ms 100 ms 150 ms 200 ms
Outlook
• Volunteers and dummies react differently in OOP
• muscular response and injury need more basic research
• As well higher QTF classes (neurological injury and facet
joint injury) advanced research
• Injury Criteria (NIC, Nkm, Rebound Velocity) need
improvement and better validation
• Optimisation up to one point must be avoided so different
tests should be performed (or one random test)
Outlook
• Females are the highest risk group• female dummy should be essential
• Stiffer cars (more aggressive pulse) could compensate the effects from improved seats
• Do not shoot first (blind) without having a well reflected program and answer questions afterwards
Thank you for your attention!