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!