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Yoganandan N, Moore J, Westerhof TA, Flierman NA. Hybrid III Manikin Lumbar Spine Loading Under Vertical Impact. Mil Med 2024; 189:55-62. [PMID: 39160828 DOI: 10.1093/milmed/usae039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/11/2024] [Accepted: 02/02/2024] [Indexed: 08/21/2024] Open
Abstract
INTRODUCTION Clinical investigations have attributed lumbar spine injuries in combat to the vertical vector. Injury prevention strategies include the determination of spine biomechanics under this vector and developing/evaluating physical devices for use in live fire and evaluation-type tests to enhance Warfighter safety. While biological models have replicated theater injuries in the laboratory, matched-pair tests with physical devices are needed for standardized tests. The objective of this investigation is to determine the responses of the widely used Hybrid III lumbar spine under the vertical impact-loading vector. MATERIALS AND METHODS Our custom vertical accelerator device was used in the study. The manikin spinal column was mounted between the inferior and superior six-axis load cells, and the impact was delivered to the inferior end. The first group of tests consisted of matched-pair repeatability tests, second group consisted of adding matched-pair tests to this first group to determine the response characteristics, and the third group consisted of repeating the earlier two groups by changing the effective torso mass from 12 to 16 kg. Peak axial, shear, and resultant forces at the two ends of the spine were obtained. RESULTS The first group of 12 repeatability tests showed that the mean difference in the axial force between two tests at the same velocity across the entire range of inputs was <3% at both ends. In the second group, at the inferior end, the axial and shear forces ranged from 4.9-25.2 kN to 0.7-3.0 kN. Shear forces accounted for a mean of 11 ± 6% and 12 ± 4% of axial forces at the two ends. In the third group of tests with increased torso mass, repeatability tests showed that the mean difference in the axial force between the two tests at the same velocity across the entire range of inputs was <2% at both ends. At the inferior end, the axial and shear forces ranged from 5.7-28.7 kN to 0.6-3.4 kN. Shear forces accounted for a mean of 11 ± 8% and 9 ± 3% of axial forces across all tests at the inferior and superior ends. Other data including plots of axial and shear forces at the superior and inferior ends across tested velocities of the spine are given in the paper. CONCLUSIONS The Hybrid III lumbar spine when subjected to vertical impact simulating underbody blast levels showed that the impact is transmitted via the axial loading mechanism. This finding paralleled the results of axial force predominance over shear forces and axial loading injuries to human spines. Axial forces increased with increasing velocity suggesting the possibility of developing injury assessment risk curves, i.e., the manikin spine does not saturate, and its response is not a step function. It is possible to associate probability values for different force magnitudes. A similar conclusion was found to be true for both magnitudes of added effective torso mass at the superior end of the manikin spinal column. Additional matched-pair tests are needed to develop injury criteria for the Hybrid III male and female lumbar spines.
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Affiliation(s)
- Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jason Moore
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Tim A Westerhof
- Explosions Ballistics & Protection, TNO Netherlands, Netherlands
| | - Nico A Flierman
- Explosions Ballistics & Protection, TNO Netherlands, Netherlands
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Yoganandan N, Baisden J, Moore J, Pintar F, Vedantam A, Shabani S, Barnes D, Loftis K. Pelvis-Sacrum-Lumbar Spine Injury Characteristics From Underbody Blast Loading. Mil Med 2023; 188:393-399. [PMID: 37948210 DOI: 10.1093/milmed/usad168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/31/2023] [Accepted: 05/09/2023] [Indexed: 11/12/2023] Open
Abstract
INTRODUCTION Combat-related injuries from improvised explosive devices occur commonly to the lower extremity and spine. As the underbody blast impact loading traverses from the seat to pelvis to spine, energy transfer occurs through deformations of the combined pelvis-sacrum-lumbar spine complex, and the time factor plays a role in injury to any of these components. Previous studies have largely ignored the role of the time variable in injuries, injury mechanisms, and warfighter tolerance. The objective of this study is to relate the time or temporal factor using a multi-component, pelvis-sacrum-lumbar spinal column complex model. MATERIALS AND METHODS Intact pelvis-sacrum-spine specimens from pre-screened unembalmed human cadavers were prepared by fixing at the superior end of the lumbar spine, pelvis and abdominal contents were simulated, and a weight was added to the cranial end of the fixation to account for torso effective mass. Prepared specimens were placed on the platform of a custom vertical accelerator device and aligned in a seated soldier posture. An accelerometer was attached to the seat platen of the device to record the time duration to peak velocity. Radiographs and computed tomography images were used to document and associate injuries with time duration. RESULTS The mean age, stature, weight, body mass index, and bone density of 12 male specimens were as follows: 65 ± 11 years, 1.8 ± 0.01 m, 83 ± 13 kg, 27 ± 5.0 kg/m2, and 114 ± 21 mg/cc. They were equally divided into short, medium, and long time durations: 4.8 ± 0.5, 16.3 ± 7.3, and 34.5 ± 7.5 ms. Most severe injuries associated with the short time duration were to pelvis, although they were to spine for the long time duration. CONCLUSIONS With adequate time for the underbody blast loading to traverse the pelvis-sacrum-spine complex, distal structures are spared while proximal/spine structures sustain severe/unstable injuries. The time factor may have implications in seat and/or seat structure design in future military vehicles to advance warfighter safety.
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Affiliation(s)
- Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jamie Baisden
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jason Moore
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Frank Pintar
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Aditya Vedantam
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Saman Shabani
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - David Barnes
- SURVICE Engineering Co., Aberdeen Proving Ground, Belcamp, MD 21005, USA
| | - Kathryn Loftis
- US Army DEVCOM Analysis Center, Aberdeen Proving Ground, MD 21005, USA
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Yoganandan N, Moore J, Humm JR, Baisden JL, Banerjee A, Pintar FA, Barnes DR, Loftis KL. Human pelvis injury risk curves from underbody blast impact. BMJ Mil Health 2023; 169:436-442. [PMID: 34711674 DOI: 10.1136/bmjmilitary-2021-001863] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 10/07/2021] [Indexed: 11/03/2022]
Abstract
INTRODUCTION Underbody blast loading can result in injuries to the pelvis and the lumbosacral spine. The purpose of this study was to determine human tolerance in this region based on survival analysis. METHODS Twenty-six unembalmed postmortem human surrogate lumbopelvic complexes were procured and pretest medical images were obtained. They were fixed in polymethylmethacrylate at the cranial end and a six-axis load cell was attached. The specimens were aligned in a seated soldier posture. Impacts were applied to the pelvis using a custom vertical accelerator. The experimental design consisted of non-injury and injury tests. Pretest and post-test X-rays and palpation were done following non-injury test, and after injury test medical imaging and gross dissections were done. Injuries were scored using the Abbreviated Injury Scale (AIS). Axial and resultant forces were used to develop human injury probability curves (HIPCs) at AIS 3+ and AIS 4 severities using survival analysis. Then ±95% CI was computed using the delta method, normalised CI size was obtained, and the quality of the injury risk curves was assigned adjectival ratings. RESULTS At the 50% probability level, the resultant and axial forces at the AIS 3+ level were 6.6 kN and 5.9 kN, and at the AIS 4 level these were 8.4 kN and 7.5 kN, respectively. Individual injury risk curves along with ±95% CIs are presented in the paper. Increased injury severity increased the HIPC metrics. Curve qualities were in the good and fair ranges for axial and shear forces at all probability levels and for both injury severities. CONCLUSIONS This is the first study to develop axial and resultant force-based HIPCs defining human tolerance to injuries to the pelvis from vertical impacts using parametric survival analysis. Data can be used to advance military safety under vertical loading to the seated pelvis.
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Affiliation(s)
- Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - J Moore
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - J R Humm
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - J L Baisden
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - A Banerjee
- Biostatistics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - F A Pintar
- Joint Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - D R Barnes
- SURVICE Engineering, Belcamp, Maryland, USA
| | - K L Loftis
- DEVCOM, Aberdeen Proving Ground, Maryland, USA
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Ye Z, Zong Z, Zhong X, Jia Y, Jiang R, Yang H, Zhou X, Du W. Characterization of Combined Blast- and Fragment-Induced Pelvic Injuries and Hemostatic Resuscitation in Rabbits. J Surg Res 2023; 285:158-167. [PMID: 36680876 DOI: 10.1016/j.jss.2022.12.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 12/01/2022] [Accepted: 12/24/2022] [Indexed: 01/20/2023]
Abstract
INTRODUCTION To establish a blast- and fragment-induced pelvic injury animal model in rabbits, observe its injury characteristics, and explore the effects of hemostatic resuscitation combined with damage control surgery (DCS) with respect to this injury model. METHODS Forty-eight rabbits were randomly allocated to four groups: group A rabbits were subjected to pelvic injury, group B rabbits to pelvic injury + DCS, group C rabbits to pelvic injury + DCS + resuscitation with Hextend, and group D rabbits to pelvic injury + DCS + Hextend + hemostatic resuscitation with tranexamic acid, fibrinogen concentrate, and prothrombin complex concentrate. Simulated blast and fragment-induced pelvic injury was produced by a custom-made machine. We implemented CT scanning and necropsy to assess the injury state and calculated the coefficient of variation (CV) of the cumulative abbreviated injury scale (AIS) to assess the reproducibility of the animal model. Immediately after instrumentation (0 h), and 1 h, 2 h, 4 h, and 8 h after injury, blood samples were taken for laboratory tests. RESULTS We found that severe pelvic injury was produced with an AIS CV value of 10.32%, and the rabbits demonstrated severe physiologic impairment and coagulo-fibrinolytic derangements with high mortality. In rabbits of group D, however, physiologic and coagulo-fibrinolytic parameters were significantly enhanced with improved organ function and lowered mortality when compared with the other three groups. CONCLUSIONS We herein established in rabbits a blast- and fragment-induced pelvic injury animal model that exhibited high reproducibility, and we demonstrated that hemostatic resuscitation plus DCS was effective in improving the outcome.
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Affiliation(s)
- Zhao Ye
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care & Department of Orthopedics, XinQiao hospital, Army Medical University
| | - Zhaowen Zong
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care & Department of Orthopedics, XinQiao hospital, Army Medical University.
| | - Xin Zhong
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
| | - Yijun Jia
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
| | - Renqing Jiang
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
| | - Haoyang Yang
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
| | - Xiaolin Zhou
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
| | - Wenqiong Du
- State Key Laboratory of Trauma, Burn and Combined Injury, Department for combat casualty care training, Training base for Army health care, Army Medical University
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Preliminary Considerations for Crime Scene Analysis in Cases of Animals Affected by Homemade Ammonium Nitrate and Aluminum Powder Anti-Personnel Landmines in Colombia: Characteristics and Effects. Animals (Basel) 2022; 12:ani12151938. [PMID: 35953927 PMCID: PMC9367463 DOI: 10.3390/ani12151938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/20/2022] [Accepted: 07/23/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Anti-personnel landmines are a major problem in countries that are subject to internal conflicts of a military or public order nature. They also continue to be a great threat to the population and biodiversity, even in post-conflict stages. Those most often used by armed groups are simple or homemade antipersonnel landmines that are designed without any type of technical regulations and standardized production systems. Their low-cost manufacturing and the use of easily accessible explosive substances for agricultural use, such as ammonium, have allowed their indiscriminate use, turning them into a huge public health problem. They are only detected when people or animals activate them, because they do not contain any materials that are detectable by traditional means. The scant literature on these artifacts focuses on injuries caused to humans, and only incidentally on field work. The objective of our study was to describe the behavior of a controlled explosion of a homemade antipersonnel landmine, and to verify the effects caused by the explosion on fauna and the environment. The results enable us to provide guidelines that may be implemented during field investigations, in which forensic veterinarians and related disciplines participate. Abstract During the armed conflict in Colombia, homemade improvised antipersonnel landmines were used to neutralize the adversary. Many active artifacts remain buried, causing damage to biodiversity by exploding. The extensive literature describes the effects and injuries caused to humans by conventional landmines. However, there is considerably less information on the behavior and effects of homemade antipersonnel landmines on fauna and good field investigation practices. Our objectives were to describe the characteristics of a controlled explosion of a homemade antipersonnel landmine (using ammonium nitrate as an explosive substance), to compare the effectiveness of some evidence search patterns used in forensic investigation, and to determine the effects on a piece of an animal carcass. The explosion generated a shock wave and an exothermic reaction, generating physical effects on the ground and surrounding structures near the point of explosion. The amputation of the foot in direct contact with the device during the explosion and multiple fractures were the main effects on the animal carcass. Finally, it was determined that finding evidence was more effective in a smaller search area. Many factors can influence the results, which must be weighed when interpreting the results, as discussed in this manuscript.
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Suchoń S, Burkacki M, Joszko K, Gzik-Zroska B, Wolański W, Sławiński G, Tavares JMRS, Gzik M. Lower Leg Injury Mechanism Investigation During an IED Blast Under a Vehicle Using an Anatomic Leg Model. Front Bioeng Biotechnol 2021; 9:725006. [PMID: 34869249 PMCID: PMC8635724 DOI: 10.3389/fbioe.2021.725006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Attacks with improvised explosive device (IED) constituted the main threat to, for example, Polish soldiers in Iraq and Afghanistan. Improving safety during transport in an armored vehicle has become an important issue. The main purpose of the presented research is to investigate the mechanism of lower leg injuries during explosion under an armored vehicle. Using a numerical anatomic model of the lower leg, the analysis of the leg position was carried out. In all presented positions, the stress limit of 160 (MPa) was reached, which indicates bone damage. There is a difference in stress distribution in anatomic elements pointing to different injury mechanisms.
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Affiliation(s)
- Sławomir Suchoń
- Department of Biomechatronics, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
| | - Michał Burkacki
- Department of Biomechatronics, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
| | - Kamil Joszko
- Department of Biomechatronics, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
| | - Bożena Gzik-Zroska
- Department of Biomaterials and Medical Devices Engineering, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
| | - Wojciech Wolański
- Department of Biomechatronics, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
| | - Grzegorz Sławiński
- Faculty of Mechanical Engineering, Institute of Mechanics and Computational Engineering, Military University of Technology, Warszawa, Poland
| | - João Manuel R S Tavares
- Departamento de Engenharia Mecânica, Faculdade de Engenharia, Instituto de Ciência e Inovação em Engenharia Mecânica e Engenharia Industrial, Universidade do Porto, Porto, Portugal
| | - Marek Gzik
- Department of Biomechatronics, Faculty of Biomedical Engineering, Silesian University of Technology, Zabrze, Poland
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Rankin IA, Nguyen TT, McMenemy L, Clasper JC, Masouros SD. The Injury Mechanism of Traumatic Amputation. Front Bioeng Biotechnol 2021; 9:665248. [PMID: 33937220 PMCID: PMC8082077 DOI: 10.3389/fbioe.2021.665248] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
Traumatic amputation has been one of the most defining injuries associated with explosive devices. An understanding of the mechanism of injury is essential in order to reduce its incidence and devastating consequences to the individual and their support network. In this study, traumatic amputation is reproduced using high-velocity environmental debris in an animal cadaveric model. The study findings are combined with previous work to describe fully the mechanism of injury as follows. The shock wave impacts with the casualty, followed by energised projectiles (environmental debris or fragmentation) carried by the blast. These cause skin and soft tissue injury, followed by skeletal trauma which compounds to produce segmental and multifragmental fractures. A critical injury point is reached, whereby the underlying integrity of both skeletal and soft tissues of the limb has been compromised. The blast wind that follows these energised projectiles completes the amputation at the level of the disruption, and traumatic amputation occurs. These findings produce a shift in the understanding of traumatic amputation due to blast from a mechanism predominately thought mediated by primary and tertiary blast, to now include secondary blast mechanisms, and inform change for mitigative strategies.
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Affiliation(s)
- Iain A Rankin
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Thuy-Tien Nguyen
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Louise McMenemy
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Academic Department of Military Surgery and Trauma, Royal Centre for Defence Medicine, ICT Centre, Birmingham Research Park, Birmingham, United Kingdom
| | - Jonathan C Clasper
- Department of Bioengineering, Imperial College London, London, United Kingdom.,Department of Trauma and Orthopaedic Surgery, Frimley Park Hospital, Surrey, United Kingdom
| | - Spyros D Masouros
- Department of Bioengineering, Imperial College London, London, United Kingdom
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