Transcript HWS DISTORSION

Whiplash injuries from a medical
perspective
Dr. Wolfram Hell
LMU Ludwig Maximilians University Munich
Institute 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
only Rear-end vehicle accidents
Netherlands:
0.5 Billion Euro/year
Great Britain:
600-800 Million Pounds/year
Switzerland:
>2 Mrd. SFR/year
Germany:
1-2 Mrd Euro/year (IFM-GDV)
USA:
10 Mrd. USD/year (IIHS)
Canada:
costs per vehicle- occupant
135 CDN$/year
Canada:
(cost reduction with better
seats approx. 54 CDN$/year)
Wealthy Countries with high compensation systems show very high economical loss
(Swizerland, Norway, Canada)
Rising Incidence of CSD Injury
40
35
35
30
29,5
25
26,9
% 20
15
20,3
10
5
0
1969
1974
1980
YEAR year
calender
traffic accidents, IFM-GDV German data material
1990
CSD Injury risk per vehicle type and weight
Folksam
GDV VS90
Ford Fiesta
Ford Fiesta
700 kg
VW Golf 1
800 kg
700 kg
VW Golf 1
800 kg
DB 190
DB 190
1200 kg
1200 kg
Opel Rekord
Opel Rekord
1200 kg
1200 kg
DB 124
DB 124
1400 kg
1400 kg
Volvo
Volvo
1400 kg
1400 kg
0
1 Injury2 Frequency
3
4
Injury
Frequency
source: IFM-GDV
weight factor and design factor
5
0
Injury Frequency
0,5
1
1,5
Injury
Frequency
2
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
0
1
2
clinical signs
NO subjective or objective symptoms
of the Cervical Spine
Cervical Spine Symptoms (subjective: pain, stiffness)
NO objective clinical signs
MICROLESION
Cervical Spine Symptoms AND
MUSCULO-SKELETTAL SIGNS
MACROLESION
Cervical Spine Symptoms AND
3
4
NEUROLOGICAL SIGNS
NEURAL DAMAGE / IRRITATION
Cervical Spine Symptoms AND
FRACTURE or DISLOCATION
Pathological correspondent, QTF
MICROLESION
QTF 1 single or multiple (ultra-)microskopic lesions
lesion is too small to cause muscular spasms
MACROLESION
QTF 2
Distorsion and soft tissue bleedings (joint capsules,
ligaments, tendons and muscles)
Secundary muscle spasm after soft tissue injury
NERVE CELL DAMAGE/ IRRITATION
QTF 3
Injuries of the neural system
caused by traumatic injury or secondary due to
Irritation caused by bleeding and inflammation
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
Neuropraxia
1
Local demyelinisation (neurons intact)
Complete recovery
Axonotmesis
2
Axons interrupted
Recovery complete or nearly complete
Neurotomesis
3
Axons and sheaths both interrupted
Recovery never complete
source: Foreman, Croft, Whiplash Injury
Williams & Wilkins, Baltimore, 1995
Suspected Pathology (Spine) I
• Zygapophysial joints
- synovial impingement
- hemarthrosis (a)
a
c
- joint capsule rupture/tear (b)
d
b
• Intervertebral disc
- tear of annulus fibrosus (c)
• Upper cervical ligaments
- tear of anterior ligament (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)
spinal cord within
spinal channel
e
space of cerebrospinal fluid
QTF and gender
rear-end collisions
gender - QTF (dv > 10 km/h)
driver N=92
100%
passenger N=38
4
4
80%
60%
83
69
69
92
40%
20%
9
9
0%
male n=47
19
22
4
female n=45
8
8
male n=12
female n=26
SOURCE: EU WHIPLASH 1 PROJECT – IFM-GDV
QTF 3
QTF 2
QTF 1
QTF 0
Visual Demonstration I
sled test (Clip) delta v 9,5 km/h
Injury mechanism at rear end collision
source: Felix Walz, modified
Phase 1
Phase 2
Phase 3
Translation and Extension
max Extension
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
EMG [mV]
120
A(h-T1) [g]
10
Semi
Sterno
8
A(h-T1)
100
6
80
4
60
2
0
40
-2
20
-4
0
-6
1
101
201
301
401
time [msec.]
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
Injury rates at rear-end collisions divided by manufacturer and type („Long Term
Injuries“ more than 6 weeks
Manufacturer
Rear end
collisions total
With injured
n
Per 1000
Long-term injured > 6
weeks
n
Per 1000
B- France
258
13
135
1
10
F- Germany
378
39
257
8
53
G- Germany
G - Germany
G- Germany
E- Germany
B- France
1087
523
229
177
252
115
88
30
18
21
294
433
380
400
328
25
18
8
7
10
64
89
101
156
156
lower middle class vehicles
SOURCE: IFM-GDV, statistics HuK Coburg Insurance 2000, damages
rating
good
medium
poor
Rear-End Impact Car Performance Statistics
Injury rates at rear-end collisions divided by manufacturer and type „Long Term
Injuries“ more than 6 weeks
Long-term injured
> 6 weeks
Per 1000
n
Per 1000
156
2
22
C- Germany
Upper middle class
Rear end
collisions
total
90
D- Germany
Small car
65
16
246
2
31
good
E- Germany
F- Germany
G- Germany
H- Germany
D- Germany
F- Germany
Upper middle class
Middle class
Middle class
Upper middle class
Middle class
Middle class
80
112
52
173
211
191
18
20
12
35
44
52
225
179
231
202
209
272
3
6
3
11
14
18
38
54
58
64
66
94
medium
Manufacturer
Weight class
With injured
n
14
SOURCE: IFM-GDV,
IFM-GDV statistics HuK Coburg Insurance 2000, damages
rating
poor
CSD- Long-Term injury
LONG TERM INJURIES SHOULD JUSTIFY HIGH PREVENTION EFFORTS
Ra tio of pe rsons re aching full recovery
if recovery takes more than 2
weeks for at least one
passenger then for all
occupants with CSD:
time to reach full recovery
n=253 persons in 208 cars
CSD and documented date of limit in earning capacity
1,0
in less than 70 days
50% will recover
,9
in 25% recovery will
take >6 months
,6
in 8% chronic
impairment
,3
,8
,7
,5
,4
,2
function
,1
0,0
censored
0
200
100
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)
Source: W2 Long Term Injury Analysis LMU
400
300
600
500
800
700
days after rear-end accident and diagnosis
900
Case example FATAL INJURY
seatback collapse after rear-end impact
Child behind driver was killed
Seatback collapse must be avoided
Source: FS 90 IFM-GDV
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!