Trauma Biomechanics: Introduction to Accidental Injury

178 Pages·2004·6.98 MB·English

by  PD Dr. Kai-Uwe Schmitt

Trauma Biomechanics
Kai-Uwe Schmitt . Peter F. Niederer· Felix Walz
Trauma Biomechanics
Introduetion to Aecidentallnjury
~ Springer
PD Dr. KAI-UWE SCHMITT
Prof. Dr. sc. techno PETER F. NIEDERER
Prof. Dr. med. FELIX WALZ
Institute for Biomedical Engineering
Swiss Federal Institute of Technology (ETH) and University of Zurich
Gloriastrasse 35
8092 Zurich
Switzerland
ISBN 978-3-540-22299-6 ISBN 978-3-662-05448-2 (eBook)
DOI 10.1007/978-3-662-05448-2
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Preface
The 2004 World Health Day is dedicated to the theme of road safety by the
World Health Organization (WHO) due mostly to the enormous socio
economic costs attributed to trafik accidents. More than 140,000 people are
injured, 3,000 killed, and 15,000 disabled for life everyday on the world's
roads. The field of trauma biomechanics, or injury biomechanics, uses the
principles of mechanics to study the response and tolerance level of
biological tissues under extreme loading conditions. Through an
understanding of mechanical factors that influence the function and
structure of human tissues, countermeasures can be developed to alleviate
or even eliminate such injuries.
This book, Trauma-Biomechanics, surveys a wide variety of topics in
injury biomechanics including anatomy, injury c1assification, injury
mechanism, and injury criteria. It is the first collection I am aware of that
lists regional injury reference values, or injury criterion, either currently in
use or proposed by both U.S. and European communities. Although the
book is meant to be an introduction for medical doctors and engineers who
are beginners in the field of injury biomechanics, sufficient references are
provided for those who wish to conduct further research, and even
established researchers will find it useful as a reference for finding the
biomechanical background of each proposed injury mechanism and injury
criterion. As more people become aware of and understand this subject, it
will someday lead to better mitigation and prevention of automotive related
injuries. I like this book very much and believe that you will find the same.
King H. Yang
Professor of Biomedical Engineering
and Mechanical Engineering
Director of Bioengineering Center
Wayne State University
Acknowledgements
The authors are gratefully indebted to several friends and colleagues, who
assisted in the development of this book through their scientific work,
comments and discussions. Particularly we would like to acknowledge the
contributions of Prof. Dr. Klaus Langwieder and Dr. Markus Muser.
Furthermore we would like to thank the members of the board of the
International Research Council on the Biomechanics of Impact (lRCOBI)
for their support.
Kai-Uwe Schmitt, Peter Niederer, Felix Walz
Contents
1 Introduction .............................................................................................. 1
2 Methods in Traurna-Biomechanics .......................................................... 7
2.1 Statistics, field studies, databases ...................................................... 7
2.2 Injury criteria, injury scales and injury risk ...................................... 9
2.3 Basic technical definitions and accident reconstruction ................. 13
2.4 Experimental models ....................................................................... 15
2.5 Crash testing .................................................................................... 18
2.5.1 Anthropomorphic test devices ................................................... 20
2.5.2 Standardised test procedures ..................................................... 27
2.6 Numerical methods ......................................................................... 32
2.7 References ....................................................................................... 36
3 Head Injuries .......................................................................................... 39
3.1 Anatomy ofthe head ....................................................................... 39
3.2 Injuries and injury mechanisms ...................................................... .41
3.3 Mechanical response ofthe head ................................................... .46
3.4 Injury criteria for head injuries ........................................................ 50
3.4.1 Head Injury Criterion (HIC) ...................................................... 51
3.4.2 Head Protection Criterion (HPC) .............................................. 52
3.4.3 3 ms criterion (a3ms) ................................................................. 53
3.4.4 Generalized Acceleration Model for Brain Injury Threshold ... 53
3.5 References ....................................................................................... 55
4 Spinal Injuries ......................................................................................... 57
4.1 Anatomy ofthe spine ...................................................................... 58
4.2 Injury mechanisms .......................................................................... 61
4.3 Biomechanical response and tolerances .......................................... 69
4.4 Injury criteria ................................................................................... 73
4.4.1 Neck injury criterion NIC ......................................................... 74
4.4.2 Nij neck injury criterion ............................................................ 75
VIII Contents
4.4.3 Neck protection criterion Nkm .................................................. 76
4.4.4 Intervetebra1 neck injury criterion (IV-NIC) ............................. 79
4.4.5 Neck displacement criterion (NDC) .......................................... 80
4.4.6 Lower Neck Load Index (LNL) ................................................ 81
4.4.7 Neck injury criteria in ECE and FMVSS .................................. 81
4.4.8 Corre1ating neck injury criteria to the injury risk ...................... 83
4.5 References ....................................................................................... 85
5 Thoracic Injuries ..................................................................................... 91
5.1 Anatomy ofthe thorax ..................................................................... 91
5.2 Injury mechanisms .......................................................................... 93
5.2.1 Rib fractures .............................................................................. 95
5.2.2 Lung injuries ............................................................................. 96
5.2.3 Injuries to other thoracic organs ................................................ 97
5.3 Biomechanica1 response .................................................................. 99
5.3.1 Fronta110ading .......................................................................... 99
5.3.2 Latera110ading ........................................................................ 10 4
5.4 Injury to1erances and criteria ......................................................... 105
5.4.1 Acceleration and force ............................................................ 107
5.4.2 Thoracic Trauma Index (TTI) ................................................. 107
5.4.3 Compression Criterion (C) ...................................................... 108
5.4.4 Viscous Criterion (VC) ........................................................... 108
5.4.5 Combined Thoracic Index (CTI) ............................................. 109
5.4.6 Other criteria ........................................................................... 110
5.5 References ..................................................................................... 110
6 AbdominalInjuries ............................................................................... 113
6.1 Anatomy of the abdomen .............................................................. 113
6.2 Injury mechanisms ........................................................................ 114
6.3 Testing the biomechanical response .............................................. 117
6.4 Injury tolerance ............................................................................. 119
6.4.1 Injury criteria ........................................................................... 120
6.5 Influence of seat be1t use ............................................................... 120
6.6 References ..................................................................................... 121
7 Injuries ofthe Pelvis and the Lower Extremities ................................. 123
7.1 Anatomy ofthe lower limbs .......................................................... 123
7.2 Injury mechanisms ........................................................................ 125
7.2.1 Injuries of the pe1vis and the proximal femur ......................... 130
7.2.2 Leg, knee and foot injury ........................................................ 132
7.3 Impact tolerance ofthe pelvis and the lower extremities .............. 134
Contents IX
7.4 Injury criteria ................................................................................. 137
7.4.1 Compression force .................................................................. 137
7.4.2 Femur Force Criterion (FFC) .................................................. 138
7.4.3 Tibia Index (TI) ....................................................................... 138
7.4.4 Other criteria ........................................................................... 139
7.5 References ..................................................................................... 139
8 Injuries ofthe Upper Extremities ......................................................... 141
8.1 Anatomy ofthe upper limbs .......................................................... 141
8.2 Injury incidences and mechanisms ................................................ 143
8.3 Impact tolerance ............................................................................ 145
8.4 Injury criteria and evaluation ofinjury risk from airbags ............. 146
8.5 References ..................................................................................... 148
9 Injury prevention .................................................................................. 151
9.1 Prevention ofhead injuries ............................................................ 152
9.2 Prevention ofsoft tissue neck injury ............................................. 153
9.2.1 Head restraint geometry and padding material ....................... 154
9.2.2 Self-aligning head restraint (SAHR) ....................................... 161
9.2.3 WHIPS seat ............................................................................. 162
9.2.4 Damping seat slide .................................................................. 162
9.2.5 WipGARD ............................................................................... 165
9.3 Prevention ofpelvic injuries and injuries ofthe lower extremities 166
9.4 Pedestrian injury countermeasures ................................................ 167
9.5 References ..................................................................................... 172
1 Introduction
The general idea of biomechanics is the application of the principles of
mechanics to biological systems. With respect to the living human,
biomechanics can be divided into several fields ofinterest ofwhich trauma
biomechanics is related to the analysis of the effects caused by mechanical
impact to the body, the so-called biomechanical response ofthe body. When
a load hits aperson, injury can result. Thus, trauma-biomechanics addresses
injuries and investigates the mechanisms that cause injury. Furthermore,
measures to prevent injury are developed. As such, trauma-biomechanics,
also called injury biomechanics, is a multidisiplinary research field uniting
engineering sciences, physics and medicine.
The same holds true for other aspects of biomechanics research such as
sports biomechanics or cellular biomechanics. While sports biomechanics
basically deals with the movement of the human body, cellular
biomechanics addresses the cellular response to a mechanical stimulus on
the microscopic scale. The knowledge obtained in such related areas greatly
contributes to trauma-biomechanics work and thus adds to the
interdisciplinary character of trauma-biomechanics.
Historically, systematic research dealing with failure of bones was
already conducted in the 19th century by Messerer, who determined the
fracture strength of human bones under static compression, tension, and
bending. However, the actual origin of trauma-biomechanics as we define it
today can be set in the time during World War 11. Observing many
accidents, predominantly in the field of military aviation, Hugh DeHaven,
the "Father of Biomechanics", started to analyse the underlying injury
mechanisms. In 1942, he published a first work titled "Mechanical Analysis
of Survival in Falls from Heights of 50 - 100 Feet". In the following years,
military aviation remained the focus of trauma-biomechanics and a lot of
the basic research like volunteer experiments to determine the
biomechanical response, the development of first anthropomorphic test
devices (dummies) and computer programmes used for mathematical
modelling of the human originate from this area.
K.-U. Schmitt et al., Trauma Biomechanics
© Springer-Verlag Berlin Heidelberg 2004
2 Introduction
Conceming the early days of automotive transportation, safety issues
were primarily considered to be a domain of the driver who was assumed to
be responsible for driving in a manner that would safeguard drivers,
passengers as weIl as occupants in other vehicles, bicyclists and
pedestrians. Restraint systems were thought of (Figure 1.1) but not widely
implemented until after World War 11. However, during the 1920s and
1930s car manufacturers constantly improved the vehicle design also with
respect to safety. Reliable and durable four-wheel breaking systems were
introduced and laminated safety glass replaced the plate glass that was used
for windshields. Further developments focused on lighting such as sealed
beam head lamps and the wheels by introducing tubeless tires. All-steel car
bodies were used instead of wooden structures and thus increased the
stiffness of the vehicles, but it was not until the 1950s that safety concepts
with a stiff passenger compartment and defined crumple zones were
realised. The steering column as a possible source of injury received early
attention, too, leading to the development of multi-part and energy
absorbing steering columns. In the 1950s and 1960s, enhanced efforts were
made towards high er safety standards in cars. These included
improvements of the crash worthiness of the instrument panel, the
development of restraint systems like the three-point belt and the airbag.
Furthermore, the terms active and passive safety were established and
Fig. 1.1 The seat belt patent (1903) by Gustave D. Lebau.