Blast Injury Science and Engineering: A Guide for Clinicians and Researchers

Foreword
Preface
Contents
Part I: Basic Science and Engineering
1: Section Overview
2: The Fundamentals of Blast Physics
2.1 Explosives and Blast: A Kinetic Effect
2.2 Explosive Systems: The Explosive Train
2.3 Energy Levels and Energy Distribution
2.4 Formation and Velocity of Fragments
2.5 Shock and Stress Transmission
2.5.1 Wave Type
2.5.2 Magnitude of the Wave
2.5.3 Impedance: A Property of the Material
2.5.4 Wave Transmission Across Interfaces
2.5.5 The Solid–Air Interface
2.6 Blast Waves
2.6.1 Change in Impedance of a Gas in a Blast Wave
2.6.2 Reflected Waves
2.6.3 Temperature Rise
2.7 Comparing Explosive Scenarios: Scaled Distance and TNT Equivalence
2.8 The Three-Dimensional World and the Physical Basis of Blast and Fragment Injury
2.9 Summary/Conclusion
References
Further Reading
3: Biomechanics in Blast
3.1 Overview
3.2 Terminology in Biomechanics
3.2.1 Biomechanics of Motion
3.2.2 Forces
3.2.3 Newton’s Laws and Kinetics
3.2.4 Functional Anatomy
3.3 Biomechanics of Force Transmission
3.3.1 Muscle Forces
3.3.2 Forces in Joints
3.4 Bringing it All Together: Forensic Biomechanics of Blast
References
Further Reading
4: Behaviour of Materials
4.1 Introduction
4.2 Materials
4.2.1 Metals
4.2.1.1 Microstructure
4.2.1.2 Imperfections
4.2.1.3 Hardening
4.2.1.4 Main Industrial Alloys
Steel
Cast Iron
Copper Alloys
Alloys of Light Metals
4.2.2 Ceramics
4.2.3 Polymers
4.2.3.1 Thermoplastics
4.2.3.2 Thermosets
4.2.3.3 Elastomers or Rubbers
4.2.4 Composites
4.2.5 Biological Materials
4.2.5.1 Biological Fluids
Protoplasm
Mucus
Synovial Fluid
4.2.5.2 Biological Solids
Actin and Elastin
Collagen
4.3 Stress Analysis
4.3.1 Introduction: General Terms
4.3.2 Stress and Strain Tensors
4.3.2.1 Stress
4.3.2.2 Strain
4.3.3 Stress States
4.3.4 Engineering Properties of Materials
4.4 Beyond Linear Elasticity
4.4.1 Hyperelasticity
4.4.2 Viscoelasticity
4.4.3 Plasticity and Failure
4.4.3.1 Plasticity
4.4.3.2 Failure
4.4.3.3 Equations of State
4.4.3.4 Shock Loading
4.4.3.5 Compaction and Unloading
4.5 Dynamic Loading
4.5.1 Elastodynamics: The Wave Equation
4.5.2 Design for Strength and Endurance: Fatigue Strength
4.5.2.1 Design of Parts and Structures
4.5.2.2 Fatigue
4.6 Summary
Further Reading
5: Fundamentals of Computational Modelling
5.1 Introduction
5.2 Computational Continuum Mechanics: Overview
5.3 Material, Spatial and Other Descriptions
5.3.1 Lagrangian Representation
5.3.2 Eulerian Representation
5.3.3 Other Forms of Spatial Integration
5.4 Implicit Finite Element Analysis
5.4.1 Meshing/Discretisation
5.4.2 Shape Functions
5.4.3 Strains and Stresses / Constitutive Laws (See Chap. 4 for More Details)
5.4.4 Formulation
5.4.4.1 Internal and External Energy: Principle of Virtual Work
5.4.4.2 Assemble
5.4.4.3 Solve
5.4.5 Evaluation of the Stiffness Matrix: Numerical Quadrature
5.4.5.1 Mapping of Elements from the s- to the x-Space: The Jacobian
5.4.6 Recover Strain and Stress
5.4.7 Overview of the Linear Static FE Method
5.4.8 Non-linear Finite Element Formulation
5.5 Explicit FEA for Dynamic Systems
5.5.1 The Single Degree of Freedom System (SDOF)
5.5.1.1 Formulation
5.5.1.2 Closed-Form Solution
5.5.1.3 Numerical Solution with Explicit Time-Stepping: The Linear Acceleration Method
5.5.2 Explicit FE and Hydrocode Techniques
5.6 Verification, Validation and Sensitivity Studies in FEA
5.6.1 Verification
5.6.2 Validation
5.6.3 Sensitivity / Uncertainty Quantification
5.7 Conclusion
Further Reading
6: Fundamentals of Blast Biology and Physiology
6.1 Basic Cellular Biology
6.1.1 Nucleus
6.1.2 Cytoplasm
6.1.3 Cell Membrane
6.2 The Biological Hierarchy
6.3 Understanding the Cellular Effect of Blast
6.3.1 The Effect of Blast on the Cell Membrane
6.3.2 The Effect of Blast on Cytoplasm
6.3.3 The Effect of Blast on the Nucleus
6.4 Whole Cell Response
6.4.1 Cell Viability
6.4.2 Mechanotransductive Pathways Within the Cell
6.4.3 Cell Interactions with Its Environment: The Inside-Out—Outside-In Concept
6.5 Summary
References
Part II: Weapons Effects and Forensics
7: Section Overview
8: Weapon Construction and Function
8.1 Introduction
8.2 Small Arms Ammunition
8.3 Mortars
8.4 Grenades
8.5 Artillery Shells
8.6 Fuzes
8.7 Munition Components
8.8 What is an IED?
8.9 IED Components
8.9.1 Main Charge
8.9.2 Container
8.9.3 Switch
8.9.4 Power Source
8.9.5 Initiator
8.9.6 Enhancements
8.10 Using IEDs to Attack Personnel
8.11 Summary
9: Blast Injury Mechanism
9.1 Blast Injury Mechanisms
9.1.1 Overview
9.1.2 Primary Blast Injury
9.1.3 Secondary Blast Injury
9.1.4 Tertiary Blast Injury
9.1.5 Quaternary Blast Effects
9.1.6 Cause of Death After Explosions
9.2 Weapons
9.2.1 Blast Weapons
9.2.2 Fragmentation Weapons
9.2.3 Blast and Fragmentation Effects
9.2.4 Mines
9.2.5 Anti-Personnel Devices
9.2.6 Anti-Vehicle Devices
9.2.7 Improvised Explosive Device
9.3 Environmental Factors
9.3.1 Open
9.3.2 Confined Spaces
9.3.3 Structural Collapse
9.3.4 Deck Slap
9.4 Suicide Bombings
9.5 Summary
References
10: Analysis of Explosive Events
10.1 The Examination of Post-Blast Scenes
10.1.1 Introduction
10.1.2 Coordination of the Post-Blast Scene
10.1.3 Optimal Capture of Forensic Evidence
10.1.4 Access Control and Cordoning
10.1.5 Explosives, Seat of Explosion, Device Identification
10.1.6 Zoning and Detailed Recording
10.1.7 Forensic Intelligence and Evidence
10.1.8 Conclusion
10.2 Case Study 1: Modelling the Blast Environment and Relating this to Clinical Injury: Experience From the 7/7 Inquest
10.2.1 Introduction
10.2.2 Approach
10.2.2.1 Work Strands
10.2.2.2 Model Design and Risk Reduction
10.2.2.3 Resources
10.2.2.4 Challenges: Quality of Information
10.2.3 Conclusion
10.3 Case Study 2: Injury Mechanism and Potential Survivability Following the 1974 Birmingham Pub Bombings
10.3.1 Introduction
10.3.2 Overview
10.3.3 Approach
10.3.3.1 Multidisciplinary Team Approach
10.3.3.2 Challenges: Missing Clinical Information
10.3.4 Findings
10.3.5 Conclusions
Annex 1
References
11: Injury Scoring Systems
11.1 Introduction
11.2 Why Score Injury?
11.3 Types of Injury Scoring Systems
11.3.1 Physiological Scores
11.3.2 Anatomical
11.3.3 Combined Scores
11.4 Limitations of Contemporary Current Scores
11.4.1 Military Specific Scores
11.4.2 The Ideal Scoring System?
11.5 Conclusions
References
Part III: Clinical Problems
12: Section Overview
Reference
13: The Immune and Inflammatory Response to Major Traumatic Injury
13.1 Introduction
13.2 Redefining the SIRS:CARS Paradigm
13.3 Mitochondrial-Derived Damage Associated Molecular Patterns: Therapeutic Targets for the Treatment of Post-Injury Immune Dysfunction?
13.4 Does Major Traumatic Injury Drive Accelerated Ageing of the Immune System?
13.5 The Post-Injury Immune Response as an Indicator of Patient Outcome
13.6 Future Directions
References
14: Foot and Ankle Blast Injuries
14.1 Introduction
14.2 The Issue
14.3 Amputation or Limb Salvage
14.4 Improving Outcomes Following Limb Salvage
14.5 Future Research
References
15: Traumatic Amputation
15.1 The Issue
15.2 Limitations of Current Injury Mechanism Theory
15.3 The Study
15.4 The Outcomes
15.5 Further Laboratory Studies
15.6 Association to Pelvic Blast Injury
References
16: Pelvic Blast Injury
16.1 Introduction
16.2 UK Military Experience
16.3 Mechanism of Injury
16.4 Pelvic Fracture Classification
16.5 Bleeding Following Pelvic Trauma
16.6 Injury Mitigation
16.7 Research Direction of the Centre for Blast Injury Studies
16.8 Conclusion
References
17: Blast Injury to the Spine
17.1 Introduction
17.2 Injury Patterns
17.2.1 Mounted Blast Injury Patterns
17.2.2 Dismounted Blast Injury Patterns
17.3 Mechanism of Blast Spinal Injuries
17.3.1 Mounted
17.3.2 Dismounted
17.4 Markers for Fatality
17.5 Associated Injuries
17.6 Outcomes
17.7 Summary
References
18: Primary Blast Lung Injury
18.1 Introduction
18.2 Epidemiology
18.3 Pathophysiology
18.4 Diagnosis
18.5 Acute Respiratory Distress Syndrome (ARDS)
18.6 Management
18.7 Future Therapy
References
19: Blast Injuries of the Eye
19.1 Primary Ocular Blast Injuries
19.2 Secondary Blast Injuries
19.3 Closed Globe Injuries
19.4 Traumatic Retinal Tears and Detachments
19.5 Tertiary Blast Injuries
19.6 Quaternary Blast Injury
19.7 Quinary Blast Injuries
19.8 Summary and Incidence
References
20: Hearing Damage Through Blast
20.1 Introduction
20.2 Blast Damage to the Outer Ear
20.3 Middle Ear Damage
20.4 Blast-Induced Impairment of the Inner Ear
20.5 Damage to the Central Nervous System
20.6 Conclusion
References
21: Torso injury from Under Vehicle Blast
21.1 Introduction
21.2 The Clinical Problem
21.3 Pattern of Injury
21.4 Mechanism of Injury
21.5 Biomechanics of Under Vehicle Blast Torso Injury
21.6 Injury Tolerance
21.7 The Future
References
22: Blast Traumatic Brain Injury
22.1 Introduction and Background
22.2 The Clinical Problem
22.2.1 Minor Blast Traumatic Brain Injury
22.2.2 Moderate to Severe Blast Traumatic Brain Injury
22.3 Current Research/Management
22.3.1 Minor Blast Traumatic Brain Injury
22.3.2 Moderate to Severe Blast Traumatic Brain Injury
22.4 Future Focus
22.4.1 Minor Blast Traumatic Brain Injury
22.4.2 Moderate to Severe Blast Traumatic Brain Injury
References
23: Heterotopic Ossification After Blast Injury
23.1 Introduction/Background
23.1.1 Background
23.1.2 HO After Blast Injury
23.1.3 Mechanism of Formation
23.1.4 Cellular and Genetic Mechanisms
23.2 The Clinical Problem and Current Management
23.2.1 Clinical Burden
23.2.2 Barrier to Rehabilitation
23.2.3 Lack of Prophylaxis
23.2.4 Surgical Management
23.3 Current Research
23.3.1 Novel Preventative Therapies
23.3.2 Risk Stratification and Early Detection
23.3.3 Animal Modelling
23.3.4 Direct Skeletal Fixation/Intraosseous Fixation of Prostheses
23.4 Future Research Focus
References
24: Pathological Cascades Leading to Heterotopic Ossification Following Blast Injury
24.1 Introduction
24.2 Key Molecular Markers of Heterotopic Ossification
24.3 Signalling Pathways in Acquired Heterotopic Ossification
24.4 Discussion and Future Therapeutic Targets
References
25: Fracture Non-Union After Blast Injury
25.1 Introduction
25.2 The Clinical Problem
25.3 Current Management
25.3.1 Nonsurgical Management of Non-Union
25.3.2 Surgical Management of the Non-Union
25.4 Future Research Foci and Needs
25.4.1 Mechanical Environment Enhancement
25.4.2 Biological Environment Enhancement
References
26: Orthopaedic-Related Infections Resulting from Blast Trauma
26.1 Introduction
26.2 Clinical Problem
26.2.1 Osteomyelitis
26.2.2 Fracture Non-Union
26.2.3 Late Amputation
26.2.4 Organisms
26.3 Current Treatment and Management Strategies
26.3.1 Antibiotics
26.3.2 Irrigation
26.3.3 Debridement
26.3.4 Compartment Syndrome
26.3.5 Skeletal Fixation
26.3.6 Negative Pressure Wound Therapy
26.4 Future Research Directions
26.4.1 Clinical
26.4.2 PreClinical
26.4.3 Novel Therapies
26.5 Summary
References
Part IV: Modelling and Mitigation
27: Section Overview
28: In Silico Models
28.1 Introduction
28.2 Axelsson Model for Blast Loading of the Chest Wall
28.3 Projectile Flight and Penetration
28.4 Fragment Penetration to the Neck
28.5 The Lower Extremity in Tertiary Blast
28.6 Defining the Parameters of Energy-Attenuating Vehicle Seats
28.7 Conclusion
References
29: In-Silico Modelling of Blast-Induced Heterotopic Ossification
29.1 Background
29.2 The Effect of the Mechanical Environment on HO
29.3 Computational Bone Remodelling Applied to Heterotopic Ossification
29.3.1 Computational Bone Remodelling
29.3.2 Application to Heterotopic Ossification
29.4 Simulating the Formation of Characteristic HO Morphologies
29.5 Discussion and Future Perspective
References
30: Physical Experimental Apparatus for Modelling Blast
30.1 Introduction
30.2 Primary Blast
30.2.1 The Shock Tube
30.2.2 The Split-Hopkinson Pressure Bar (SHPB)
30.2.3 Other Devices
30.3 Secondary Blast
30.3.1 Gas Gun
30.3.2 Other Devices
30.4 Tertiary Blast
30.4.1 Drop Towers
30.4.2 Solid-Blast Injury Simulators
30.5 Conclusions
References
31: In Vitro Models of Primary Blast: Organ Models
31.1 Introduction
31.2 Brain
31.3 Lung
31.4 Abdominal Organs
31.5 Eye
31.6 Summary
References
32: Modelling Blast Brain Injury
32.1 In Silico Models
32.2 Ex Vivo Models
32.3 In Vitro Models
32.4 In Vivo Animal Models
32.4.1 Animal Species
32.4.2 Generation of Overpressure Waves
32.4.2.1 Free-Field Explosives
32.4.2.2 Blast Tubes
32.4.2.3 Shock Tubes
32.4.3 Critical Aspects
32.4.3.1 Anaesthesia and Analgesia
32.4.3.2 Pressure Wave Characteristics
32.4.3.3 Animal Head Orientation Relative to the Direction of the Pressure Wave
32.4.3.4 Head Mobile Versus Head Restrained
32.4.3.5 Head Only Blast Exposure (Thorax Protection) Versus Whole Body Blast Exposure (no Thorax Protection)
32.4.3.6 Single Blast Versus Repeated Blasts
32.4.3.7 Outcomes
32.5 Conclusion
References
33: Post Mortem Human Tissue for Primary, Secondary and Tertiary Blast Injury
33.1 Benefits of Using PMHS
33.2 Issues with Using PMHS
33.3 Examples of Using PMHS for Blast Injury Research
33.4 Conclusion
References
34: Surrogates: Anthropometric Test Devices
34.1 Introduction
34.2 A Brief History of ATDs
34.3 ATDs Used to Assess Occupant Safety in Blast
34.3.1 The Hybrid III ATD
34.3.2 The Eurosid-2RE ATD (ES-2re)
34.3.3 The MIL-lx
34.3.4 Warrior Injury Assessment Manikin
34.3.5 Frangible, Single-Use Surrogates
34.4 Injury Risk Assessment
34.5 Summary
References
Further Reading
35: Physical Models for Assessing Primary and Secondary Blast Effects
35.1 Introduction
35.2 Physical Models for Primary Blast Experiments
35.3 Physical Models for Assessing the Effectiveness of Secondary Blast
35.3.1 Single Fragment Testing
35.3.2 Combined Blast/Fragmentation Investigations
References
36: Tertiary Blast Injury and its Protection
36.1 Introduction
36.2 Vehicles
36.3 Infrastructure
References
37: Optimising the Medical Coverage of Personal Armour Systems for UK Armed Forces Personnel
37.1 Introduction
37.1.1 Essential and Desirable Medical Coverage
37.1.2 Vulnerable Anatomical Structures
37.2 Medical Coverage Definitions by Body Region
37.2.1 Head and Face
37.2.2 Neck
37.2.3 Torso
37.2.4 Upper Arm
37.2.5 Pelvis and Thigh
37.3 Computerised Comparisons in the Anatomical Coverage Provided by Different Armour Designs
37.4 Coverage of Personal Armour Issued to UK Armed Forces Personnel
37.4.1 Coverage Provided by Hard Plates as Shown in COAT
37.4.2 Medical Coverage Provided by the VIRTUS Helmet
37.4.3 Quantifying the Coverage Provided by Side Plates
37.4.4 Optimising the Coverage of Arm Protection
37.5 Conclusions
References
Part V: Rehabilitation
38: Section Overview
39: Survive to Thrive
39.1 An Anecdote of Adjustment
39.2 Short Biography
40: Rehabilitation Lessons from a Decade of Conflict
40.1 The Rehabilitation Challenge
40.2 Principles of Military Rehabilitation
40.2.1 Early Assessment
40.2.2 Exercise-Based Rehabilitation
40.2.3 Cross-Disciplinary Working: The Interdisciplinary Team
40.2.4 Active Case Management
40.2.5 Rapid Access to Specialist Opinion/Investigations
40.3 Hospital-Based Rehabilitation of the Blast-Injured Amputee
40.3.1 Early Rehabilitation in Critical Care
40.3.2 Early Function and Progress to Ward-Based Rehabilitation
40.3.3 The Rehabilitation Coordinating Officer
40.3.4 Innovating Practice
40.3.5 Pain Management
40.4 Military Rehabilitation of the Blast-Injured Amputee
40.4.1 Measuring Progress
40.4.2 Periodic Intensive Residential Rehabilitation (PIRR)
40.4.3 Prosthetics: Practical Lessons Learned
40.4.4 Prosthetic Rehabilitation Programme
40.4.4.1 Bilateral Amputees
40.4.4.2 Unilateral Amputees
40.4.4.3 Other Considerations
40.4.4.4 Osseointegration/Direct Skeletal Fixation (DSF)
40.4.5 The Challenge of Transition
40.5 Conclusion
References
41: Prosthetics and Innovation
41.1 Introduction
41.2 Prosthetic Hardware
41.2.1 Upper Limb Prostheses
41.2.2 Lower Limb Prosthetics
41.3 Prosthetic Control
41.3.1 Body-Powered Systems
41.3.2 Commercial Actuated Prosthesis Control
41.4 Research Oriented Actuated Prosthesis Control
41.4.1 Regression-Based Continuous Control
41.4.2 Control Systems Based on Invasive EMG Systems
41.4.3 Alternative Control Approaches
41.5 Sensory Feedback
41.5.1 Non-invasive Sensory Feedback
41.5.2 Invasive Sensory Feedback
41.6 Surgical Techniques for Improved Prosthetic Experience
41.7 Conclusion and Future Outlook
References
42: Orthotics
42.1 Introduction
42.2 Device Type
42.3 Custom Dynamic Orthoses
42.4 Design Considerations
42.5 Training, Evaluation, and Outcomes
42.6 Summary
References
43: Sockets and Residuum Health
43.1 Introduction
43.2 Prosthetic Devices
43.2.1 Transtibial
43.2.2 Transfemoral
43.2.3 Through-Knee (Knee Disarticulation)
43.2.4 Socket Construction
43.2.5 Liners
43.2.6 Socket Suspension
43.2.6.1 Cuff Mechanisms
43.2.6.2 Harness Suspension
43.2.6.3 Sub-Atmospheric Pressure Suspension
Suction
Vacuum-Assisted Suspension
43.2.7 Socks
43.2.8 Orientation/Alignment
43.2.9 Components
43.3 Overview of Amputee Issues
43.3.1 Fit and Pressure Distribution
43.3.2 Volume Fluctuation
43.3.3 Temperature and Thermoregulation
43.3.4 Skin Conditions and Infection
43.3.5 Other Musculoskeletal Pathologies Related to the Socket
43.4 Understanding and Optimising Socket Fit
43.4.1 Qualitative Assessment
43.4.2 Computational Methods and Socket Fit
43.4.3 Sensing Methods
43.4.3.1 Strain Gauges
43.4.3.2 Piezoresistive Sensors
43.4.3.3 Piezoelectric Sensors
43.4.3.4 Capacitive Sensors
43.4.3.5 Optical Fibre Sensors
43.4.3.6 Optoelectronic Sensors
43.4.3.7 Sensor Mounting Techniques
43.4.4 Optimisation of Interfacial Stresses
43.4.5 Accounting for Volume Fluctuation
43.4.6 Heat Management
43.4.7 Surgical Methods
43.4.7.1 Transtibial
43.4.7.2 Transfemoral
43.5 Summary
References
44: Bone Health in Lower-Limb Amputees
44.1 Introduction to the Mechanics of Bone Structure and Prediction in Finite Element Modelling
44.2 Bone Changes in Amputees
44.2.1 General Trends of Decreased Bone Density
44.2.2 Mechanisms of Bone Loss
44.2.3 Aetiology of Bone Loss in Amputees
44.3 Clinical Study on Bone Changes in Amputees
44.4 Computational Modelling of Stress and Strain in Amputees
44.5 Discussion
References
45: Musculoskeletal Health After Blast Injury
45.1 Introduction
45.2 Prevalence of Joint Health and Secondary Injuries
45.3 The Relationship Between Movement Biomechanics and Joint Health
45.3.1 Lower Limb Joint Mechanics and Osteoarthritis
45.3.2 Low-Back Mechanics and Pain
45.4 Implications for Rehabilitation and Future Directions
45.5 Conclusion
References
46: Biomechanics of Blast Rehabilitation
46.1 Loading the Musculoskeletal System
46.1.1 Musculoskeletal Capacity
46.2 Computational Modelling to Analyse Musculoskeletal Loading
46.3 Examples
46.3.1 Biomechanics and Osteoarthritis in Amputees
46.3.2 Optimising Prosthetic Parameters
46.3.3 Functional Electrical Stimulation Interventions
46.4 Conclusion
References
47: Pain
47.1 Pathophysiology
47.1.1 Introduction
47.1.2 Definitions
47.1.3 Acute Versus Chronic Pain
47.1.4 The Role of Nervous System Inflammation
47.1.5 Peripheral Nerve Injury (PNI)
47.1.6 Phantom Limb Pain (PLP)
47.1.7 A Current Conceptual Model of PNI and NeuP
47.1.8 Patient Assessment
47.1.9 Clinical Correlates
47.2 Treatment
47.2.1 Introduction
47.2.2 Immediate Response
47.2.3 Perioperative Care
47.2.4 Chronic Pain and Rehabilitation
47.2.4.1 Introduction
47.2.4.2 Treatment
47.2.4.3 Comorbidities
47.2.4.4 Prognosis
47.3 Summary
References
Glossary
Index