Fractures of the thoracolumbar spine sustained by soldiers in vehicles attacked by improvised explosive devices

Lumbar Spine Orientation Affects Compressive Fracture Outcome

PURPOSE

Understanding how spinal orientation affects injury outcome is essential to understand lumbar injury biomechanics associated with high-rate vertical loading.

METHODS

Whole-column human lumbar spines (T12-L5) were dynamically loaded using a drop tower to simulate peak axial forces associated with high-speed aircraft ejections and helicopter crashes. Spines were allowed to maintain natural lordotic curvature for loading, resulting in a range of orientations. Pre-test X-rays were used to quantify specimen orientation at the time of loading. Primary fracture types were identified (wedge, n = 6; burst, n = 4; hyperextension, n = 4) and compared for loading parameters and lumbar orientation.

RESULTS

Fracture type was dependent on peak acceleration, bending moment, Cobb angle, sagittal spinal tilt, and location of the applied load.

CONCLUSIONS

Lumbar spine orientation under high-rate axial acceleration affected the resulting fracture type. Analysis of pre-test X-rays revealed that spines that sustained wedge and burst fractures were oriented straighter at the time of loading. The load was applied centrally to T12 in spines with burst fractures, and anteriorly to T12 in spines with wedge fractures. Spines that sustained hyperextension fracture had lower peak accelerations, larger Cobb angles at the time of loading, and sustained larger extension moments. Fracture presentation is an important and understudied factor that influences biomechanical stability, clinical course, and long-term patient outcomes.

Factors Affecting the Situational Awareness of Armored Vehicle Occupants

In the field of armored vehicles, up to 70% of accidents are associated with low levels of situational awareness among the occupants, highlighting the importance of situational awareness in improving task performance. In this study, we explored the mechanisms influencing situational awareness by simulating an armored vehicle driving platform with 14 levels of experimentation in terms of five factors: experience, expectations, attention, the cueing channel, and automation. The experimental data included SART and SAGAT questionnaire scores, eye movement indicators, and electrocardiographic and electrodermal signals. Data processing and analysis revealed the following conclusions: (1) Experienced operators have higher levels of situational awareness. (2) Operators with certain expectations have lower levels of situational awareness. (3) Situational awareness levels are negatively correlated with information importance affiliations and the frequency of anomalous information in non-primary tasks. (4) Dual-channel cues lead to higher levels of situational awareness than single-channel cues. (5) Operators' situational awareness is lower at high automation levels.

Comparison of Adult Female and Male PMHS Pelvis and Lumbar Response to Underbody Blast

The goal of this study was to gather and compare kinematic response and injury data on both female and male whole-body Post-mortem Human Surrogates (PMHS) responses to Underbody Blast (UBB) loading. Midsized males (50th percentile, MM) have historically been most used in biomechanical testing and were the focus of the Warrior Injury Assessment Manikin (WIAMan) program, thus this population subgroup was selected to be the baseline for female comparison. Both small female (5th percentile, SF) and large female (75th percentile, LF) PMHS were included in the test series to attempt to discern whether differences between male and female responses were predominantly driven by sex or size. Eleven tests, using 20 whole-body PMHS, were conducted by the research team. Preparation of the rig and execution of the tests took place at the Aberdeen Proving Grounds (APG) in Aberdeen, MD. Two PMHS were used in each test. The Accelerative Loading Fixture (ALF) version 2, located at APG's Bear Point range was used for all male and female whole-body tests in this series. The ALF was an outdoor test rig that was driven by a buried explosive charge, to accelerate a platform holding two symmetrically mounted seats. The platform was designed as a large, rigid frame with a deformable center section that could be tuned to simulate the floor deformation of a vehicle during a UBB event. PMHS were restrained with a 5-point harness, common in military vehicle seats. Six-degree-of-freedom motion blocks were fixed to L3, the sacrum, and the left and right iliac wings. A three-degree-of freedom block was fixed to T12. Strain gages were placed on L4 and multiple locations on the pelvis. Accelerometers on the floor and seat of the ALF provided input data for each PMHS' feet and pelvis. Time histories and mean peak responses in z-axis acceleration were similar among the three PMHS groups in this body region. Injury outcomes were different and seemed to be influenced by both sex and size contributions. Small females incurred pelvis injuries in absence of lumbar injures. Midsized males had lumbar vertebral body fractures without pelvis injuries. And large females with injuries had both pelvis and lumbar VB fractures. This study provides evidence supporting the need for female biomechanical testing to generate female response and injury thresholds. Without the inclusion of female PMHS, the differences in the injury patterns between the small female and midsized male groups would not have been recognized. Standard scaling methods assume equivalent injury patterns between the experimental and scaled data. In this study, small female damage occurred in a different anatomical structure than for the midsized males. This is an important discovery for the development of anthropomorphic test devices, injury criteria, and injury mitigating technologies. The clear separation of small female damage results, in combination with seat speeds, suggest that the small female pelvis injury threshold in UBB events lies between 4 - 5 m/s seat speed. No inference can be made about the small female lumbar threshold, other than it is likely at higher speeds and/or over longer duration. Male lumbar spine damage occurred in both the higher- and lower lower-rate tests, indicating the injury threshold would be below the seat pulses tested in these experiments. Large females exhibited injury patterns that reflected both the small female and midsized male groups - with damaged PMHS having fractures in both pelvis and lumbar, and in both higher- and lower- rate tests. The difference in damage patterns between the sex and size groups should be considered in the development of injury mitigation strategies to protect across the full population.

The I-PREDICT 50th Percentile Male Warfighter Finite Element Model: Development and Validation of the Thoracolumbar Spine

Military personnel are commonly at risk of lower back pain and thoracolumbar spine injury. Human volunteers and postmortem human subjects have been used to understand the scenarios where injury can occur and the tolerance of the warfighter to these loading regimes. Finite element human body models (HBMs) can accurately simulate the mechanics of the human body and are a useful tool for understanding injury. In this study, a HBM thoracolumbar spine was developed and hierarchically validated as part of the Incapacitation Prediction for Readiness in Expeditionary Domains: an Integrated Computational Tool (I-PREDICT) program. Constitutive material models were sourced from literature and the vertebrae and intervertebral discs were hexahedrally meshed from a 50th percentile male CAD dataset. Ligaments were modeled through attaching beam elements at the appropriate anatomical insertion sites. 94 simulations were replicated from experimental PMHS tests at the vertebral body, functional spinal unit (FSU), and regional lumbar spine levels. The BioRank (BRS) biofidelity ranking system was used to assess the response of the I-PREDICT model. At the vertebral body level, the I-PREDICT model showed good agreement with experimental results. The I-PREDICT FSUs showed good agreement in tension and compression and had comparable stiffness values in flexion, extension, and axial rotation. The regional lumbar spine exhibited "good" biofidelity when tested in tension, compression, extension, flexion, posterior shear, and anterior shear (BRS regional average = 1.05). The validated thoracolumbar spine of the I-PREDICT model can be used to better understand and mitigate injury risk to the warfighter.

Combat Injury Profile in Urban Warfare

INTRODUCTION

Combat ground maneuvers consist of various platforms and have several environmental characteristics, influenced by the terrain, the operational mission, and the force's capabilities. This study assesses data on injuries sustained during urban warfare, aiming to evaluate the relationship between injury characteristics, maneuver platform, and personal protective gear on the battlefield.

MATERIALS AND METHODS

IDF soldiers injured infantry soldiers from the "Cast Lead" and the "Protective Edge" operations in the Gaza Strip (2008-2009 and 2014, respectively) were divided into four groups according to the maneuver platform and the environment: mounted infantry (armored and unarmored vehicle) and dismounted infantry (urban and open area). The primary outcome was the severity of the injury, and the secondary outcome was the injured body part.

RESULTS

Overall, 588 casualties were included in the final analysis, of whom 507 were dismounted infantry soldiers (265 in open terrain and 242 in urban area) and 81 were mounted infantry soldiers (20 in unarmored and 61 were injured in armored vehicles). The Injury Severity Score was similar in all subgroups. Open terrain subgroups were found to have fewer head injuries and higher levels of lower extremity injuries, similar to the unarmored vehicle group. More facial injuries were documented in the urban area group.

CONCLUSIONS

The Injury Severity Score was not influenced by environmental protection. Although we found differences in the injured body parts, further studies on the exact mechanism of injury are needed to elucidate further the relationship and differences between the various platforms used and injuries seen in urban warfare, aiming for tailor-made protection.

Landmine Injury Resulting in Comminuted Lumbar Facet Fracture as a Cause of Lumbar Stenosis and Spondylolisthesis

Lumbar facet fractures are rarely reported and have been linked to sports and spine surgery. We describe the case of a 77-year-old patient who sustained an injury from multiple landmine blasts during the Vietnam War. He had low back pain since that time, which was initially managed conservatively. However, the pain progressed over decades to severe neurogenic claudication that greatly restricted his quality of life. Neuroimaging revealed the presence of bone fragments impinging on the spinal canal at the L5/6 level (transitional anatomy) that resulted from a comminuted fracture of the lumbar facet at the inferior articular process. We performed an L5/6 decompressive laminectomy, with removal of these fragments, and posterior instrumented fusion, with substantial improvement in symptoms. This case illustrates a unique mechanism of lumbar facet fracture and the biomechanic origination, natural history, and optimal treatment of this entity. We expand on the spectrum of lumbosacral injuries associated with the combat blast injury that have only increased in prevalence in recent conflicts.

A comparison of fracture response in female and male lumbar spine in simulated under body blast component tests

Underbody blasts (UBB) from mines and improvised explosive devices in military combat can cause debilitating spine injuries to vehicle mounted soldiers. Due to the exclusion of females in combat roles in prior US Department of Defense policy, UBB exposure and injury have predominantly affected male soldiers. Recent policy changes have opened many combat roles to women serving in the US Military (Carter, 2015) and have increased the need to understand the injury potential for female Warfighters. The goal of this study was to investigate the fracture response of adult female lumbar spines compared to adult male spines in UBB relevant loading to identify potential differences in either fracture mechanism or force. Results are presented for 15 simulated UBB spine compression tests using three small female (SF), five large female (LF), and seven mid-sized male (MM) post-mortem human subjects (PMHS). These PMHS groups align to 5th- and 75th-percentile female and 50th-percentile males, based on height and weight from the 2012 Anthropometric Survey of U.S. Army Personnel (Gordon et al., 2014). Both small females and large females (similar in size to the males) were included to assess the role of size and/or sex in the response. Tests were conducted at Virginia Tech on a cam-driven linear compression rig, which included a 6-axis load cell and ram accelerometer to evaluate the fracture. Fracture was visualized through high-speed x-ray video. All female and male spines exhibited similar fracture initiation at the end plates and progression through the vertebral body. The resulting severe compression and burst fractures were representative of reported theatre injuries (Freedman et al., 2014). Mean axial fracture forces were -4182 ± 940 N (SF), -6225 ± 1180 N (LF), -5459 ± 1472 N (All Females) and -7993 ± 2445 N (MM). The SF group was found to have statistically significant differences in mean fracture force compared to both LF and MM groups, while no significant difference was found between LF and MM groups, although the mean force at initial fracture was lower for the LF group. The All-Females group Fz mean was significantly different from the MM group. These data suggest that the significant difference in weight between the SF and LF groups, did have an influence on the Fz outcome, when controlling for sex. Conversely, controlling for size in the LF and MM comparison, sex did influence the mean Fz, but was not statistically significant. Groups with combined sex and size differences, however, did show significant differences in mean Fz. Further study is warranted to understand whether sex or size has a larger effect on fracture force. Mean ram displacement (spine compression) values at fracture initiation were -6.0 ± 5.3 mm (SF), -4.4 ± 0.8 mm (LF), -5.0 ± 3.0 mm (All Females), -6.2 ± 4.5 mm (MM). Spine compression did not seem to be largely influenced by either sex or size, and none of the groups was found to have significant differences in mean displacement values.

How War Has Shaped Neurosurgery

Many strides have been made in neurosurgery during times of war, helping to improve the outcomes of patients in dire circumstances. World War I introduced the concepts of early operation for trauma, forward-operating hospitals, and galeal sutures as well as techniques for careful debridement. It laid the groundwork for neurosurgery to become a specialty within medicine as well. World War II brought about the use of expedited medical evacuation, mobile neurosurgical units, improved resuscitation strategies, cranioplasty, and early laminectomy with decompression. The Korean and Vietnam Wars built on concepts from World Wars I and II, helping to establish the importance of watertight dural closure, external drainage systems after cranial trauma, multidisciplinary care, and infection prevention strategies. In the post-Vietnam period, we have seen significant technological advances allowing neurosurgeons to move farther ahead than most throughout history could have imagined. The significance of secondary brain injury, vascular injury, and the underlying pathophysiology of traumatic insults has been elucidated over the years since the Vietnam War, allowing for great advances in the care of our patients. Each major war throughout history has contributed greatly to the specialty of neurosurgery, each with its own innovations culminating in guidelines, strategies, and standards of practice that allow us to deliver the highest standard of care to our patients.

Temporal corridors of forces and moments, and injuries to pelvis-lumbar spine in vertical impact simulating underbody blast

Pelvis and lumbar spine fractures occur in falls, motor vehicle crashes, and military combat events. They are attributed to vertical impact from the pelvis to the spine. Although whole-body cadavers were exposed to this vector and injuries were reported, spinal loads were not determined. While previous studies determined injury metrics such as peak forces using isolated pelvis or spine models, they were not conducted using the combined pelvis-spine columns, thereby not accounting for the interaction between the two body regions. Earlier studies did not develop response corridors. The study objectives were to develop temporal corridors of loads at the pelvis and spine and assess clinical fracture patterns using a human cadaver model. Vertical impact loads were delivered at the pelvic end to twelve unembalmed intact pelvis-spine complexes, and pelvis forces and spinal loads (axial, shear and resultant and bending moments) were obtained. Injuries were classified using clinical assessments from post-test computed tomography scans. Spinal injuries were stable in eight and unstable in four specimens. Pelvis injuries included ring fractures in six and unilateral pelvis in three, sacrum fractures in ten, and two specimens did not sustain any injuries to the pelvis or sacrum complex. Data were grouped based on time to peak velocity, and ± one standard deviation corridors about the mean of the biomechanical metrics were developed. Time-history corridors of loads at the pelvis and spine, hitherto not reported in any study, are valuable to assess the biofidelity of anthropomorphic test devices and assist validating finite element models.

Advancements in the treatment of traumatic spinal cord injury during military conflicts

Significant advancements in the treatment of spinal cord injury (SCI) were developed in the setting of military conflicts, partly due to the large numbers of injuries sustained by service members. No effective SCI treatment options existed into the early 20th century, and soldiers who sustained these injuries were usually considered untreatable. Extensive progress was made in SCI treatment during and after World War II, as physical therapy was increasingly encouraged for patients with SCI, multidisciplinary teams oversaw care, pathophysiology was better understood, and strategies were devised to prevent wound infection and pressure sores. Recent conflicts in Iraq and Afghanistan have caused a substantial rise in the proportion of SCIs among causes of casualties and wounds, largely due to new forms of war and weapons, such as improvised explosive devices. Modern military SCIs resulting from blast mechanisms are substantively different from traumatic SCIs sustained by civilians. The treatment paradigms developed over the past 100 years have increased survival rates and outcomes of soldiers with SCI. In this paper, the authors review the role of military conflicts in the development of therapeutic interventions for SCI and discuss how these interventions have improved outcomes for soldiers and civilians alike.

Curiosity or Underdiagnosed? Injuries to Thoracolumbar Spine with Concomitant Trauma to Pancreas

The pancreas is at risk of damage as a consequence of thoracolumbar spine injury. However, there are no studies providing prevalence data to support this assumption. Data from European hospitals documented in the TraumaRegister DGU^® (TR-DGU) between 2008–2017 were analyzed to estimate the prevalence of this correlation and to determine the impact on clinical outcome. A total of 44,279 patients with significant thoracolumbar trauma, defined on Abbreviated Injury Scale (AIS) as ≥2, were included. Patients transferred to another hospital within 48 h were excluded to prevent double counting. A total of 135,567 patients without thoracolumbar injuries (AIS ≤ 1) were used as control group. Four-hundred patients with thoracolumbar trauma had a pancreatic injury. Pancreatic injuries were more common after thoracolumbar trauma (0.90% versus (vs.) 0.51%, odds ratio (OR) 1.78; 95% confidence intervals (CI), 1.57–2.01). Patients with pancreatic injuries were more likely to be male (68%) and had a higher mean Injury Severity Score (ISS) than those without (35.7 ± 16.0 vs. 23.8 ± 12.4). Mean length of stay (LOS) in intensive care unit (ICU) and hospital was longer with pancreatic injury. In-hospital mortality was 17.5% with and 9.7% without pancreatic injury, respectively. Although uncommon, concurrent pancreatic injury in the setting of thoracolumbar trauma can portend a much more serious injury.

Influence of occupant collision state parameters on the lumbar spinal injury during frontal crash

Introduction

Developed a detailed finite element model of spine and validated with the experimental or cadaveric tests to gain insight on occupant safety.

Objectives

This study evaluates the influence of occupant collision state parameters such as height of the drop, occupant seating posture (occupant posture angle) and mass of the upper body on the risk of lumbar spinal injury during a frontal crash.

Methods

This parametric evaluation utilizing response surface methodology (RSM) performed. ANOVA was used to test the significance of parameters.

Results

Higher axial force of 3547 N is observed with higher dropping distance of 1500 mm. Similarly, higher strain and energy absorption were observed for the same dropping condition respectively.

Conclusion

The result shows that all the factors considered in the experiment contribute to the risk of spinal lumbar injury during the frontal crash. Among all, height of the drop and the occupant posture angle are the most significant parameters in determining the lumbar spinal injury of occupant. It is observed that the injury criteria are directly proportional to the posture angle of the seat and height of drop.

Mechanisms and timing of injury to the thoracic, lumbar and sacral spine in simulated underbody blast PMHS impact tests

During an underbody blast (UBB) event, mounted occupants are exposed to high rate loading of the spine via the pelvis. The objective of this study was to simulate UBB loading conditions and examine mechanisms of injury in the thoracic, lumbar and sacral spine. Fourteen instrumented, whole-body, postmortem human subject (PMHS) experiments were performed using the WSU-decelerative horizontal sled system. The specimens were positioned supine on a decelerative sled, which then impacted an energy absorbing system mounted to a concrete barrier. Variables included the peak velocity and time-to-peak velocity for seat and floor, and the presence or absence of personal protective equipment (PPE) and seat padding. Post-test CT scans and autopsies were performed to identify the presence and severity of injuries. Acceleration and angular rate data collected at vertebra T1, T5, T8, T12, and S1 were used to assess injury timing and mechanisms. Additionally, joint time-frequency analysis (JTFA) of the spinal Z acceleration of the sacrum and vertebrae was developed with the aim of verifying spinal fracture timing. Injuries observed in the spine were attributed to axial compression applied through the pelvis, together with flexion moment due to the offset in the center of gravity of the torso, and are consistent with UBB-induced combat injuries reported in the literature. The injury timing estimation techniques discussed in this study provide a time interval when the fractures are predicted to have occurred. Furthermore, this approach serves as an alternative to the estimation methods using acoustic sensors, force and acceleration traces, and strain gauges.

Developing a heuristic relationship to predict the spinal injury during vertical impact for autonomous vehicle and bio environment

BACKGROUND AND OBJECTIVE

Recent research and tested data suggested that spinal injuries occur more often in a frontal impact. Most of the published information is focused on the lumbar spinal injury with respect to axial compression force by varying the height of drops. Parametric studies on the lumbar spinal injury are very scanty. Therefore, the present investigation aimed to optimize the effects of drop height, torso weight and seat angle on the characterization of lumbar injury criteria METHODS: A detailed finite element model of a spine with multi-segmented spinal columns is developed and validated with the experimental or cadaveric tests using CORA evaluation. Hence, Dynamic loading studies or weight drop techniques were used to characterize the effect of drop height, seat angle and torso weight of the upper body on the lumbar spinal injury during a frontal impact. Parametric simulations were carried out using response surface methodology (RSM). Test of significance (p < 0.05) on the parameters was carried out using ANOVA. Desirability Function Approach is used to optimize the parameters for better safety design.

RESULTS

The result shows that all the factors considered in the experiment are related to the risk of lumbar spinal injury during the frontal impact. All the factors selected, the drop height, torso weight and the seat angle were the most prominent element in determining the lumbar spinal injury. The injury increased with the increase in the posture angle of the seat. Optimal parameters were determined for the better safety of the occupants as seat angle of 105°, drop height 500 mm and torso weight of 25 kg in vehicle design. During vertical impact, posterior undergoes maximum impact in the portions of vertebra and confirmed with the patient case study fracture of vertical drop incident.

CONCLUSIONS

This research insight gives an improved understanding of the parametric influence of design alternatives to minimize the risk of lumbar spinal injury in automotive vehicles. The optimal combination of drop height and the seat angle provides futuristic view on autonomous vehicle seat design.

Comparison of Human Surrogate Responses in Underbody Blast Loading Conditions

Impact biomechanics research in occupant safety predominantly focuses on the effects of loads applied to human subjects during automotive collisions. Characterization of the biomechanical response under such loading conditions is an active and important area of investigation. However, critical knowledge gaps remain in our understanding of human biomechanical response and injury tolerance under vertically accelerated loading conditions experienced due to underbody blast (UBB) events. This knowledge gap is reflected in anthropomorphic test devices (ATDs) used to assess occupant safety. Experiments are needed to characterize biomechanical response under UBB relevant loading conditions. Matched pair experiments in which an existing ATD is evaluated in the same conditions as a post mortem human subject (PMHS) may be utilized to evaluate biofidelity and injury prediction capabilities, as well as ATD durability, under vertical loading. To characterize whole body response in the vertical direction, six whole body PMHS tests were completed under two vertical loading conditions. A series of 50th percentile hybrid III ATD tests were completed under the same conditions. Ability of the hybrid III to represent the PMHS response was evaluated using a standard evaluation metric. Tibial accelerations were comparable in both response shape and magnitude, while other sensor locations had large variations in response. Posttest inspection of the hybrid III revealed damage to the pelvis foam and skin, which resulted in large variations in pelvis response. This work provides an initial characterization of the response of the seated hybrid III ATD and PMHS under high rate vertical accelerative loading.

A numerical investigation of factors affecting lumbar spine injuries in frontal crashes

Recent field data analyses have shown that lumbar spine fractures occurred more frequently in late model vehicles than the early ones in frontal crashes. Therefore, the objective of this study was to investigate risk factors associated with lumbar spine fractures in frontal crashes. Parametric simulations were conducted using a set of validated vehicle driver compartment model, restraint system model, and a HIII mid-size male crash test dummy model. Risk factors considered in the study included occupant seating posture, crash pulse, vehicle pitch angle, seat design, anchor pre-tensioner, dynamic locking tongue, and shoulder belt load limiter. ANOVA and ANCOVA were used to test the statistical significance (p < 0.05). Simulation results showed that all the factors that reduced the risk of submarining increased the lumbar spine forces, indicating a direct conflict between submarining and lumbar spine fractures. Among all the factors selected, seat structure is the most significant factor in determining the lumbar spine force (p < 0.001). Crash pulse severity, time at which the peak crash deceleration reached, and pitch angle are also crucial for lumbar spine force. Specifically, increase in vehicle pitch angle increased lumbar spine force, but reduced injury measures to other body regions; while a crash pulse with early peak produced greater lumbar spine force than that with a late peak. On average, more reclined posture increased the lumbar spine force compared to upright posture, and decreases in the coefficient of friction between the pelvis and the seat cushion reduced the lumbar spine force. However, they are not statistically significant. This study provided better understanding of effects from design countermeasures to reduce occupant lumbar spine injuries in new generation of vehicle models.

Analysis Regarding the Risk of Injuries of Soldiers Inside a Vehicle during Accidents Caused by Improvised Explosive Devices

This article presents the description of the mechanism of selected dysfunctions of the human skeletal system and internal organs. The problem is wide and requires extensive experimental and numerical research. This article presents the outline of the problem regarding the creation of personal injuries of soldiers inside armored vehicles. The explanation of the mechanism of injuries caused as a result of strong effects of pulse forces, resulting from both the consequences of the wave of pressure created during an explosion, as well as high accelerations of the vehicle’s hull, is presented herein. Examples of the results of numerical analyses of the pressure wave impact from an explosion are presented in the Article. LS-Dyna software was used to perform the numerical calculations. The analyses were carried out using the Conwep algorithm implemented in the calculation code. The significance of calculation methods, thanks to which it is possible to recreate a simulation in which there is a risk of injuries of soldiers without posing a threat to their health and life, should be noted here. The main parts of the human body, such as the bottom limb, the pelvic belt, the cervical spine and the abdomen, have been considered. Mechanisms causing typical injuries of soldiers inside vehicles under which explosives are detonated have been analyzed for particular body parts through multiple numerical simulations. The analysis of the process of injury creation has been conducted on the basis of the statistical data regarding the most common injuries of soldiers. The validation process of numerical analyses was carried out using the results of experimental research.

Management of a high thoracic chance fracture

PURPOSE

Chance fracture of the high thoracic spine is rare, and its impact on the adjacent cervical spine can be important.

METHODS

We present the case of a 16-year-old male, who fell down from a 2 m height, in an unknown context as he has a mental retardation, and no witness saw the accident. Initial CT scan revealed a comminuted depressed fracture of the right parietal bone, associated with a chance fracture at the level of T3 with a kyphosis and bilateral lung contusion.

RESULTS

The patient underwent neurosurgical treatment for elevation and reconstruction of the parietal fracture; he also underwent, 2 days later, a posterior spinal correction and fusion with T1-to-T5 instrumentation. The patient returned to normal walking on day 7 with a satisfactory clinical and radiological result at 1 year.

CONCLUSION

Literature is sparse on the treatment of high thoracic chance fractures. The current case shows that early surgical management should prevent a secondary kyphotic deformity that may need a more aggressive treatment at a later stage.

Blast Injury in the Spine: Dynamic Response Index Is Not an Appropriate Model for Predicting Injury

BACKGROUND

Improvised explosive devices are a common feature of recent asymmetric conflicts and there is a persistent landmine threat to military and humanitarian personnel. Assessment of injury risk to the spine in vehicles subjected to explosions was conducted using a standardized model, the Dynamic Response Index (DRI). However, the DRI was intended for evaluating aircraft ejection seats and has not been validated in blast conditions.

QUESTIONS/PURPOSES

We asked whether the injury patterns seen in blast are similar to those in aircraft ejection and therefore whether a single injury prediction model can be used for both situations.

METHODS

UK military victims of mounted blast (seated in a vehicle) were identified from the Joint Theatre Trauma Registry. Each had their initial CT scans reviewed to identify spinal fractures. A literature search identified a comparison population of ejected aircrew with spinal fractures. Seventy-eight blast victims were identified with 294 fractures. One hundred eighty-nine patients who had sustained aircraft ejection were identified with 258 fractures. The Kruskal-Wallis test was used to compare the population injury distributions and Fisher's exact test was used to assess differences at each spinal level.

RESULTS

The distribution of injuries between blast and ejection was not similar. In the cervical spine, the relative risk of injury was 11.5 times higher in blast; in the lumbar spine the relative risk was 2.9 times higher in blast. In the thoracic spine, the relative risk was identical in blast and ejection. At most individual vertebral levels including the upper thoracic spine, there was a higher risk of injury in the blast population, but the opposite was true between T7 and T12, where the risk was higher in aircraft ejection.

CONCLUSIONS

The patterns of injury in blast and aircraft are different, suggesting that the two are mechanistically dissimilar. At most vertebral levels there is a higher relative risk of fracture in the blast population, but at the apex of the thoracic spine and in the lower thoracic spine, there is a higher risk in ejection victims. The differences in relative risk at different levels, and the resulting overall different injury patterns, suggest that a single model cannot be used to predict the risk of injury in ejection and blast.

CLINICAL RELEVANCE

A new model needs to be developed to aid in the design of mine-protected vehicles for future conflicts.

Effects of acceleration level on lumbar spine injuries in military populations

BACKGROUND CONTEXT

Clinical studies have indicated that thoracolumbar trauma occurs in the civilian population at its junction. In contrast, injury patterns in military populations indicate a shift to the inferior vertebral levels of the lumbar spine. Controlled studies offering an explanation for such migrations and the associated clinical biomechanics are sparse in literature.

PURPOSE

The goals of this study were to investigate the potential roles of acceleration loading on the production of injuries and their stability characteristics using a human cadaver model for applications to high-speed aircraft ejection and helicopter crashes.

STUDY DESIGN

Biomechanical laboratory study using unembalmed human cadaver lumbar spinal columns.

METHODS

Thoracolumbar columns from post-mortem human surrogates were procured, x-rays taken, intervertebral joints and bony components evaluated for degeneration, and fixed using polymethylmethacrylate. The inferior end was attached to a platform via a load cell and uniaxial accelerometer. The superior end was attached to the upper metal platform via a semi-circular cylinder. The pre-flexed specimen was preloaded to simulate torso mass. The ends of the platform were connected to the vertical post of a custom-designed drop tower. The specimen was dropped inducing acceleration loading to the column. Axial force and acceleration data were gathered at high sampling rates, filtered, and peak accelerations and inertia-compensated axial forces were obtained during the loading phase. Computed tomography images were used to identify and classify injuries using the three-column concept (stable vs. unstable trauma).

RESULTS

The mean age, total body mass, and stature of the five healthy degeneration-free specimens were 42 years, 73 kg, and 167 cm. The first two specimens subjected to peak accelerations of approximately 200 m/sec(2) were classified as belonging to high-speed aircraft ejection-type and the other three specimens subjected to greater amplitudes (347-549 m/sec(2)) were classified as belonging to helicopter crash-type loadings. Peak axial forces for all specimens ranged from 4.8 to 7.2 kN. Ejection-type loaded specimens sustained single-level injuries to the L1 vertebra; one injury was stable and the other was unstable. Helicopter crash-type loaded specimens sustained injuries at inferior levels, including bilateral facet dislocation at L4-L5 and L2-L4 compression fractures, and all specimens were considered unstable at least at one spinal level.

CONCLUSIONS

These findings suggest that the severity of spinal injuries increase with increasing acceleration levels and, more importantly, injuries shift inferiorly from the thoracolumbar junction to lower lumbar levels. Acknowledging that the geometry and load carrying capacity of vertebral bodies increase in the lower lumbar spine, involvement of inferior levels in trauma sparing the superior segments at greater acceleration inputs agree with military literature of caudal shift in injured levels. The present study offers an experimental explanation for the clinically observed caudal migration of spinal trauma in military populations as applied to high-speed aircraft ejection catapult and helicopter crashes.

The combat burst fracture study--results of a cohort analysis of the most prevalent combat specific mechanism of major thoracolumbar spinal injury

INTRODUCTION

In 2009-2010, military physicians hypothesized that a new pattern of spinal injury had emerged, resulting from improvised explosive device assault on up-armored vehicles, associated with a high rate of point of first contact fracture and neurological injury-the combat burst fracture. We sought to determine the incidence of all thoracolumbar (TL) burst fractures and combat burst fractures in 2009-2010 as compared to two antecedent years.

METHODS

A screening process identified all individuals who sustained TL burst fractures in the time-period studied. Demographics, injury-specific characteristics, mechanism of injury, surgical interventions and early complications were recorded. Incidence rates were calculated for the three time periods using total deployed troop-strength and number of LRMC combat admissions as denominators. The incidences of TL burst fractures within each year group and by mechanism were compared, and clinical characteristics and process of care were described.

RESULTS

Between 2007-2010, 65 individuals sustained a TL burst fracture. The incidence of these injuries in 2009-2010 was 2.1 per 10,000 soldier-years and accounted for 3.0 % of LRMC combat-casualty admissions, a significant increase from 0.6 % and 1.1 % in 2007-2008 and 2008-2009, respectively (p ≤ 0.001). In 2009-2010, US soldiers were 3.4-4.6 times more likely to sustain a TL burst fracture compared to 2008-2009 and 2007-2008 (p < 0.001), and the most common mechanism of injury was IED vs. vehicle (65 %)-the combat burst fracture mechanism. Neurological deficits were present in 43 % of TL burst fractures and 1/3 were complete injuries. Spinal fixation was performed in 68 % overall and 74 % of combat burst fractures.

CONCLUSIONS

There was a 3.4- to 4.6-fold increase in TL burst fractures in 2009-2010 compared to antecedent years. The primary driver of this phenomenon was the marked increased in combat burst fractures. Mitigating/preventing the mechanism behind this major spinal injury is a key research initiative for the US military. Level of Evidence III (Case-control).

Biomechanics of Thoracolumbar Burst and Chance-Type Fractures during Fall from Height

Study Design In vitro biomechanical study. Objective To investigate the biomechanics of thoracolumbar burst and Chance-type fractures during fall from height. Methods Our model consisted of a three-vertebra human thoracolumbar specimen (n = 4) stabilized with muscle force replication and mounted within an impact dummy. Each specimen was subjected to a single fall from an average height of 2.1 m with average velocity at impact of 6.4 m/s. Biomechanical responses were determined using impact load data combined with high-speed movie analyses. Injuries to the middle vertebra of each spinal segment were evaluated using imaging and dissection. Results Average peak compressive forces occurred within 10 milliseconds of impact and reached 40.3 kN at the ground, 7.1 kN at the lower vertebra, and 3.6 kN at the upper vertebra. Subsequently, average peak flexion (55.0 degrees) and tensile forces (0.7 kN upper vertebra, 0.3 kN lower vertebra) occurred between 43.0 and 60.0 milliseconds. The middle vertebra of all specimens sustained pedicle and endplate fractures with comminution, bursting, and reduced height of its vertebral body. Chance-type fractures were observed consisting of a horizontal split fracture through the laminae and pedicles extending anteriorly through the vertebral body. Conclusions We hypothesize that the compression fractures of the pedicles and vertebral body together with burst fracture occurred at the time of peak spinal compression, 10 milliseconds. Subsequently, the onset of Chance-type fracture occurred at 20 milliseconds through the already fractured and weakened pedicles and vertebral body due to flexion-distraction and a forward shifting spinal axis of rotation.

Surgical removal of metallic foreign body (shrapnel) from the lumbosacral spine and the treatment of chronic osteomyelitis: a case report

We report a case of a retired soldier who was severely injured by an explosion in 1993 during the war in Bosnia and Herzegovina. Among other wounds, he suffered an explosive wound in the lumbosacral spine with steel foreign body (shrapnel). A year after primary wound treatment, a purulent fistula appeared which was treated and stopped with antimicrobial therapy. Subsequently, fistula which was activated several times after the antibiotic therapy was discontinued, but in the last eight years, the fistula has been continuously present so the patient decided on surgery. During surgery, the shrapnel was removed from the lumbosacral spine and there was debridement of necrotic bone. During two weeks of peri-operative and postoperative period, chronic osteomyelitis was treated by intravenous ciprofloxacin and gentamycin, and after that by a combination of rifampicin and trimethoprim-sulfamethoxazole orally, for six months. The patient did not show any signs of infection after two years of follow-up.

Evaluation of immediate postoperative complications and outcomes among military personnel treated for spinal trauma in Afghanistan: a cohort-control study of 50 cases

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

The objective of the study was to compare neurological outcomes and complication rates between a series of combat-injured patients treated in Afghanistan (AFG) and those treated at Landstuhl Regional Medical Center (LRMC).

SUMMARY OF BACKGROUND DATA

At present, no studies have addressed the ideal timing and setting for surgical stabilization in combat-injured soldiers who sustain spinal trauma.

METHODS

Soldiers who sustained spine injuries while deployed to Afghanistan and who underwent surgery in theater or at LRMC between 2010 and 2011 were identified. Demographic information, injury-specific data, neurological status, type of surgical intervention, postoperative complications, and need for additional surgery were abstracted for all patients. Neurological improvement was the primary dependent variable. Secondary variables included the risk of developing complications and the need for additional surgery. Statistical analysis was performed using t tests, and the Fisher exact test was used for categorical variables.

RESULTS

Between 2010 and 2011, 30 individuals were treated in AFG, and 20 received surgery at LRMC. Neurological improvement occurred in 10% of AFG patients and 5% of those treated at LRMC. Complications occurred in 40% of AFG patients and in 20% of the LRMC group. Twenty-three percent of AFG patients required additional spine surgery after leaving Afghanistan. There was no statistical difference in neurological improvement between the AFG and LRMC groups (P=0.64). Soldiers who received surgery in AFG were at significantly increased risk of requiring additional procedures (P=0.03).

CONCLUSIONS

Soldiers treated in theater did not have statistically higher rates of neurological improvement as compared with those treated at LRMC. Patients treated in-theater were at elevated risk for the need for additional surgery. This study is among the first to evaluate clinical outcomes after surgical intervention for war-related spinal trauma.

LEVEL OF EVIDENCE

Level III (case-control).

The unusual chance fracture: case report & literature review

The Chance fracture represents a spinal lesion caused by a flexion-distraction injury pattern. We describe a rare case of a male driver admitted at the Emergencies of our Institution, level A Trauma center. The was involved in an automobile accident without wearing a seatbelt. Radiological findings of plain radiography and computed tomography (CT) demonstrated a horizontal fracture extending across the vertebral body to the posterior elements with loss of vertebral height at the anterior aspect of T12. Based on these findings, the diagnosis of a T12 Chance fracture was established. The patient was treated conservatively with a thoracolumbar orthosis, without any subsequent disabilities. Although Chance fractures are rare lesions, they should always be considered in spinal injuries, even in cases of motor-vehicle accidents where no seatbelt is used.

Identical fracture patterns in combat vehicle blast injuries due to improvised explosive devices; a case series

Background

In November 2008, a surgical team from the Red Cross Hospital Beverwijk, the Netherlands, was deployed in Afghanistan for three months to attend in the army hospital of Kandahar.

During their stay, four incidents of armored personnel carriers encountering an improvised explosive device were assessed. In each incident, two soldiers were involved, whose injuries were strikingly similar.

Case presentation

The described cases comprise paired thoracic vertebral fractures, radial neck fractures, calcaneal fractures and talar fractures. Moreover, the different types of blast injury are mentioned and related to the injuries described in our series. Acknowledging the different blast mechanisms is important for understanding possible injury patterns.

Conclusion

From this case series, as well as the existing literature on injury patterns caused by blast injuries, it seems appropriate to pay extra attention to bodily areas that were injured in other occupants of the same vehicle. Obviously, the additional surveillance for specific injuries should be complementary to the regular trauma work-up (e.g., ATLS).

Initial predictors associated with outcome in injured multiple traumatic limb amputations: a Kandahar-based combat hospital experience

INTRODUCTION

Improvised explosive devices (IEDs) are the defining mechanism of injury during Operation Enduring Freedom. This is a retrospective analysis of initial management for IED blast injuries presenting with bilateral, traumatic, lower-extremity (LE) amputations with and without pelvic and perineal involvement.

METHODS

A database of trauma admissions presenting to a North Atlantic Treaty Organization (NATO) Role 3 combat hospital in southern Afghanistan over a 7-month period was created to evaluate the care of this particular injury pattern. Patients were included if they were received from point of injury with at least bilateral traumatic LE amputations and had vital signs with initial resuscitation efforts.

RESULTS

Thirty-two presented with double LE amputations (36%) and nine with triple amputations (10%). After excluding 10 patients who failed to meet the inclusion criteria, 22 patients were analysed. The mean age was 29 years, and the average ISS and admission haemoglobin were 22 and 11.3mgl(-1), respectively. Patients received an average of 54 units of blood products and underwent 1.6 operations with a mean operative time of 142.5min. The pattern of injury was associated with an increase in the total blood products required for resuscitation (pelvis n=12, p=0.028, gastrointestinal tract (GI) n=14, p=0.02, perineal n=15, p=0.036). There was no relationship between ISS or admission haemoglobin and the need for massive transfusion. Low Glasgow Coma Scale (GCS) was associated with increased 30-day mortality. Hollow viscus injury and operative hemipelvectomy were also associated with mortality.

CONCLUSIONS

Early 30-day follow-up demonstrated that IED injuries with bilateral LE amputations with and without pelvic and perineal involvement are survivable injuries. Standard measures of injury and predictors of survival bore little relationship to observed outcomes and may need to be re-evaluated. Long-term follow-up is needed to assess the extent of functional recovery and overall morbidity and mortality.

Multiple associated injuries are common with spine fractures during war

BACKGROUND CONTEXT

The nature of concomitant injuries associated with spine fractures in American military personnel engaged in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF) has been poorly documented in the literature.

PURPOSE

To characterize the incidence and epidemiology of associated injuries (AIs) in American military personnel with spine fractures sustained during OEF and OIF from 2001 to 2009.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

American military personnel who were injured in a combat zone and whose medical data were abstracted in the Joint Theater Trauma Registry (JTTR).

OUTCOME MEASURES

Not applicable.

METHODS

The JTTR was queried using International Statistical Classification of Disease, Ninth Revision codes to identify all individuals who sustained spine injuries in OEF or OIF from October 2001 to December 2009. Medical records of all identified service members were abstracted to ensure accuracy and avoid duplication. Demographic information, including sex, age, and military rank, were obtained for all patients. Information regarding fracture type, spine region, mechanism of injury, and the presence of AIs was collected for all patients.

RESULTS

Seventy-eight percent of patients with a spine fracture sustained at least one AI, with an average of 3.4 AIs per patient. Musculoskeletal injuries were most common, followed by chest, abdomen, and traumatic brain injuries. Most patients were injured by an explosive mechanism (62%). Head and face traumas were more common with cervical fractures, chest with thoracic injuries, and abdominopelvic injuries with lumbosacral fractures. Pelvis and acetabulum fractures were common after helicopter crashes, tibia/fibula injuries after explosions, thoracoabdominal injuries after gunshot wounds, and traumatic brain injuries after falls. Most patients (76%) sustained multiple spine fractures.

CONCLUSION

Spine fractures sustained in OEF and OIF have high rates of AIs. Musculoskeletal AIs are the most common, but visceral injuries adjacent to the spine fracture frequently occur. Multiple spine injuries are more prevalent after military trauma.

Military penetrating spine injuries compared with blunt

BACKGROUND CONTEXT

The nature of blunt and penetrating injuries to the spine and spinal column in a military combat setting has been poorly documented in the literature. To date, no study has attempted to characterize and compare blunt and penetrating spine injuries sustained by American servicemembers.

PURPOSE

The purpose of this study was to compare the military penetrating spine injuries with blunt spine injuries in the current military conflicts.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

All American military servicemembers who have been injured while deployed in Iraq (Operation Iraqi Freedom) and Afghanistan (Operation Enduring Freedom) whose medical data have been entered into the Joint Theater Trauma Registry (JTTR).

METHODS

The JTTR was queried for all American servicemembers sustaining an injury to the spinal column or spinal cord while deployed in Iraq or Afghanistan. These data were manually reviewed for relevant information regarding demographics, mechanism of injury, surgical intervention, and neurologic injury.

RESULTS

A total of 598 servicemembers sustained injuries to the spine or spinal cord. Isolated blunt injuries were recorded in 396 (66%) servicemembers and 165 (28%) sustained isolating penetrating injuries. Thirty servicemembers (5%) sustained combined blunt and penetrating injuries to the spine. The most commonly documented injuries were transverse process fractures, compression fractures, and burst fractures in the blunt-injured servicemembers versus transverse process fractures, lamina fractures, and spinous process fractures in those injured with a penetrating injury. One hundred four (17%) servicemembers sustained spinal cord injuries, comprising 10% of blunt injuries and 38% of penetrating injuries (p<.0001). Twenty-eight percent (28%) of blunt-injured servicemembers underwent a surgical procedure compared with 41% of those injured by penetrating mechanisms (p=.4). Sixty percent (n=12/20) of blunt-injured servicemembers experienced a neurologic improvement after surgical intervention at follow-up compared with 43% of servicemembers (n=10/23) who underwent a surgical intervention after a penetrating trauma (p=.28). Explosions accounted for 58% of blunt injuries and 47% of penetrating injuries, whereas motor vehicle collisions accounted for 40% of blunt injuries and 2% of penetrating injuries. Concomitant injuries to the abdomen, chest, and head were common in both groups.

CONCLUSIONS

Blunt and penetrating injuries to the spinal column and spinal cord occur frequently in the current conflicts in Iraq and Afghanistan. Penetrating injuries result in significantly higher rates of spinal cord injury and trend toward increased rates of operative interventions and decreased neurologic improvement at follow-up.

Wartime spine injuries: understanding the improvised explosive device and biophysics of blast trauma

The improvised explosive device (IED) has been the most significant threat by terrorists worldwide. Blast trauma has produced a wide pattern of combat spinal column injuries not commonly experienced in the civilian community. Unfortunately, explosion-related injuries have also become a widespread reality of civilian life throughout the world, and civilian medical providers who are involved in emergency trauma care must be prepared to manage casualties from terrorist attacks using high-energy explosive devices. Treatment decisions for complex spine injuries after blast trauma require special planning, taking into consideration many different factors and the complicated multiple organ system injuries not normally experienced at most civilian trauma centers. Therefore, an understanding about the effects of blast trauma by spine surgeons in the community has become imperative, as the battlefield has been brought closer to home in many countries through domestic terrorism and mass casualty situations, with the lines blurred between military and civilian trauma. We set out to provide the spine surgeon with a brief overview on the use of IEDs for terrorism and the current conflicts in Iraq and Afghanistan and also a perspective on the biophysics of blast trauma.

Complications associated with military spine injuries

BACKGROUND CONTEXT

To assess the presence of complications associated with spine injuries in the Global War on Terror.

PURPOSE

To characterize the effect of complications in and around the battlefield during Operation Enduring Freedom and Operation Iraqi Freedom from 2001 to 2009.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

American servicemembers sustaining spine injury during combat.

METHODS

Extracted medical records of warriors identified by the Joint Theater Trauma Registry from October 2001 to December 2009. Complications were defined as unplanned medical events that required further intervention. Complications were classified as major or minor and further subdivided among groups, including surgical and nonsurgical management, mounted (in an armored vehicle) or dismounted at the time of injury, and blunt or penetrating trauma.

RESULTS

Major complications were encountered in 55 servicemembers (9%), and 38 (6%) sustained minor complications. Forty-four percent (n=24) of those with major complications had more than one complication. Eleven servicemembers sustained three or more complications. There were five intraoperative complications, and 50 occurred in the perioperative period. Intraoperative complications included gastrointestinal injury, dural tear, and instrument malposition. Among patients who sustained complications, precipitating spinal injuries occurred primarily in combat (n=43 [78%]) and resulted from blunt (18) or penetrating (25) mechanisms. Complications occurred in 10 (3%) of those treated nonoperatively and 45 (25%) of those receiving surgery. Complications were higher in the dismounted group (80%) as compared with those who were mounted in vehicles at the time of injury (20%). Thirty-five percent (n=24) of surgically treated, dismounted, and penetrating injured servicemembers had complications. Seventeen percent (n=8) of surgically treated and blunt injured mounted servicemembers and 20% (n=13) of dismounted servicemembers had complications. Among the dismounted and nonspinal cord-injured servicemembers, both blunt (p=.002) and penetrating injured (p<.0005) treated with surgery were correlated with complications. Only the dismounted servicemembers with spinal cord injuries because of a penetrating mechanism were also at an increased risk for complications (p<.0005).

CONCLUSIONS

Patients treated with surgery appear to be at increased complication risk regardless of the mechanism of injury. Uparmored vehicles may safeguard servicemembers from spine injuries and complications associated with their treatment. This may be reflective of the fact that less severe spinal and concomitant injuries are sustained in the precipitating trauma because of the protection afforded by the vehicle. Dismounted soldiers had more complications in all groups regardless of type of management or injury mechanism.

Are spine injuries sustained in battle truly different?

BACKGROUND CONTEXT

The severity and prognosis of combat-related injuries to the spine and spine injuries sustained unrelated to direct combat have not been previously compared. Differences may have implications on tactics, treatment strategies, and directions for future research.

PURPOSE

Compare the severity and prognosis of battle and nonbattle injuries to the spine.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

American military personnel who were injured in a combat zone and whose medical data were abstracted in the Joint Theater Trauma Registry (JTTR).

METHODS

The JTTR was queried using International Statistical Classification of Diseases, Ninth Revision codes to identify all individuals who sustained battle and nonbattle injuries to the neck, back, spinal column, or spinal cord in Operation Iraqi Freedom or Operation Enduring Freedom from October 2001 to December 2009. Medical records of all identified servicemembers were individually reviewed. Demographic information, including sex, age, military rank, date of injury, and final disposition, was obtained for all patients. Spinal injuries were categorized according to anatomic location, associated neurologic involvement, precipitating mechanism of injury (MOI), and concomitant wounds. These data points were compared for the groups battle spine injuries (BSIs) and nonbattle spine injuries (NBSIs).

RESULTS

Five hundred two servicemembers sustained a total of 1,834 battle injuries to the spinal column, including 1,687 fractures (92%), compared with 92 servicemembers sustaining 267 nonbattle spinal column injuries, with 241 (90%) fractures. Ninety-one BSI servicemembers (18% of patients) sustained spinal cord injuries (SCIs) with 41 (45%) complete SCIs, compared with 13 (14% of patients) nonbattle SCIs with six (46.2%) complete injuries (p=.92). The reported MOI for 335 BSI servicemembers (66.7%) was an explosion compared with one NBSI explosive injury. Eighty-four patients (17%) sustained gunshot wounds (GSWs) in battle compared with five (5.2%) nonbattle GSWs. Fifteen patients (3.0%) sustained a battle-related fall compared with 29 (30%) nonbattle-related falls. Battle spine injury servicemembers underwent significantly higher rates of surgical interventions (p<.0001), were injured by high-energy injury mechanisms at a significantly greater rate (p<.0001), and demonstrated a trend toward lower neurologic recovery rates after SCI (p=.16).

CONCLUSIONS

Battle spine injury and NBSI are separate entities that may ultimately have disparate long-term prognoses. Nonbattle spine injury patients, although having similar MOIs compared with civilian spinal trauma, maintain a different patient demographic. Further research must be directed at accurately quantifying the long-term disabilities of all spine injuries sustained in a combat theater, whether they are the result of battle or not.

The effect of vehicle protection on spine injuries in military conflict

BACKGROUND CONTEXT

To evaluate the effect of critical time periods in vehicle protection on spine injuries in the Global War on Terror.

PURPOSE

To characterize the effect of method of movement on and around the battlefield during Operation Enduring Freedom and Operation Iraqi Freedom from 2001 to 2009 in terms of its impact on the incidence and severity of spinal fractures sustained in combat.

STUDY DESIGN/SETTING

Retrospective study.

PATIENT SAMPLE

Mounted and dismounted American servicemembers who were injured during combat.

METHODS

Extracted medical records of servicemembers identified in the Joint Theater Trauma Registry from October 2001 to December 2009. Methods of movement were defined as mounted or dismounted. Two time periods were compared. Cohorts were created for 2×2 analysis based on method of movement and the time period in which the injury occurred. Time period 1 and 2 were separated by April 1, 2007, which correlates with the initial fielding of the modern class of uparmored fighting vehicles with thickened underbelly armor and a V-shaped hull. Our four comparison groups were Dismounted in Time Period 1 (D1), Dismounted in Time Period 2 (D2), Mounted in Time Period 1 (M1), and Mounted in Time Period 2 (M2).

RESULTS

In total, 1,819 spine fractures occurred over the entire study period. Four hundred seventy-two fractures (26%) were sustained in 145 servicemembers who were mounted at the time of injury, and 1,347 (74%) were sustained by 404 servicemembers who were dismounted (p<.0005). The incidence of fractures in the dismounted cohort (D1+D2) was significantly higher than in the mounted cohort (M1+M2) in both time periods (D1 vs. M1, 13.75 vs. 3.95/10,000 warrior-years [p<.001] and D2 vs. M2, 11.15 vs. 4.89/10,000 warrior-years [p<.0001]). In both the mounted and dismounted groups, the thoracolumbar (TL) junction was the most common site of injury (36.1%). Fractures to the TL junction (T10-L3) increased significantly from Time Period 1 to 2 (34% vs. 40% of all fractures, respectively, p=.03). Thoracolumbar fractures were significantly more severe in that there were more Arbeitsgemeinschaft fur Osteosynthesefragen/Magerl Type A injuries versus all TL fractures, 1.75 versus 2.68/10,000 or 27% of all spine fractures in Time Period 1 versus 40% in Time Period 2 (p=.007). Furthermore, there were significantly fewer minor fractures (spinous process and transverse process fractures) (p<.0001). In Time Period 2, significantly more TL spine fractures were classified as major fractures, according to the Denis classification system, in both the mounted and dismounted groups; M1 group, 61 of 226 (27%) versus the M2 group, 86 of 246 (34%) (p<.0005) and 173 of 786 (22%) in the D1 group versus 193 of 561 (34%) in the D2 group. The spinal cord injury (SCI) incidence did not change in the mounted groups in Time Period 1 (7 of 71, 9.9%) versus Time Period 2 (7 of 74, 9.5%) (p=.935). In the dismounted groups, SCI actually decreased from D1 (55 of 228, 24%) to D2 (28 of 176, 16%) (p=.0428).

CONCLUSIONS

The incidence of spine fractures and SCI is significantly higher in dismounted operations. The data suggest that current uparmored vehicles convey greater protection against spinal fracture compared with dismounted operations in which servicemembers are engaged on foot, outside their vehicles. The TL junction is at greatest risk for spine fractures sustained in mounted and dismounted combat operations. Recently, the incidence of TL fractures, especially severe fractures, has significantly increased in mounted operations. Although there has been an increased incidence of TL spine fractures, in context of the number of servicemembers deployed in support of Operation Enduring Freedom/Operation Iraqi Freedom, these severe fractures still represent a relatively rare event.

Spinal injuries after improvised explosive device incidents: implications for Tactical Combat Casualty Care

BACKGROUND

Tactical Combat Casualty Care aims to treat preventable causes of death on the battlefield but deemphasizes the importance of spinal immobilization in the prehospital tactical setting. However, improvised explosive devices (IEDs) now cause the majority of injuries to Canadian Forces (CF) members serving in Afghanistan. We hypothesize that IEDs are more frequently associated with spinal injuries than non-IED injuries and that spinal precautions are not being routinely employed on the battlefield.

METHODS

We examined retrospectively a database of all CF soldiers who were wounded and arrived alive at the Role 3 Multinational Medical Unit in Kandahar, Afghanistan, from February 7, 2006, to October 14, 2009. We collected data on demographics, injury mechanism, anatomic injury descriptions, physiologic data on presentation, and prehospital interventions performed. Outcomes were incidence of any spinal injuries.

RESULTS

Three hundred seventy-two CF soldiers were injured during the study period and met study criteria. Twenty-nine (8%) had spinal fractures identified. Of these, 41% (n = 12) were unstable, 31% (n = 9) stable, and 28% indeterminate. Most patients were injured by IEDs (n = 212, 57%). Patients injured by IEDs were more likely to have spinal injuries than those injured by non-IED-related mechanisms (10.4% vs. 2.3%; p < 0.01). IED victims were even more likely to have spinal injuries than patients suffering blunt trauma (10.4% vs. 6.7%; p = 0.02). Prehospital providers were less likely to immobilize the spine in IED victims compared with blunt trauma patients (10% [22 of 212] vs. 23.0% [17 of 74]; p < 0.05).

CONCLUSIONS

IEDs are a common cause of stable and unstable spinal injuries in the Afghanistan conflict. Spinal immobilization is an underutilized intervention in the battlefield care of casualties in the conflict in Afghanistan. This may be a result of tactical limitations; however, current protocols should continue to emphasize the judicious use of immobilization in these patients.

Use of imaging in trauma decision-making

Damage Control Radiology describes the process where imaging aids the decision making process in a trauma setting and is an important part of Damage Control Surgery and Resuscitation. This article outlines how radiology fits in to the primary and secondary surveys and discusses the role of imaging modalities such as ultrasound and CT. The importance of deployed radiology to aid rapid diagnosis and decision making is described.

A New PMHS Model for Lumbar Spine Injuries During Vertical Acceleration

Ejection from military aircraft exerts substantial loads on the lumbar spine. Fractures remain common, although the overall survivability of the event has considerably increased over recent decades. The present study was performed to develop and validate a biomechanically accurate experimental model for the high vertical acceleration loading to the lumbar spine that occurs during the catapult phase of aircraft ejection. The model consisted of a vertical drop tower with two horizontal platforms attached to a monorail using low friction linear bearings. A total of four human cadaveric spine specimens (T12-L5) were tested. Each lumbar column was attached to the lower platform through a load cell. Weights were added to the upper platform to match the thorax, head-neck, and upper extremity mass of a 50th percentile male. Both platforms were raised to the drop height and released in unison. Deceleration characteristics of the lower platform were modulated by foam at the bottom of the drop tower. The upper platform applied compressive inertial loads to the top of the specimen during deceleration. All specimens demonstrated complex bending during ejection simulations, with the pattern dependent upon the anterior-posterior location of load application. The model demonstrated adequate inter-specimen kinematic repeatability on a spinal level-by-level basis under different subfailure loading scenarios. One specimen was then exposed to additional tests of increasing acceleration to induce identifiable injury and validate the model as an injury-producing system. Multiple noncontiguous vertebral fractures were obtained at an acceleration of 21 g with 488 g/s rate of onset. This clinically relevant trauma consisted of burst fracture at L1 and wedge fracture at L4. Compression of the vertebral body approached 60% during the failure test, with -6,106 N axial force and 168 Nm flexion moment. Future applications of this model include developing a better understanding of the vertebral injury mechanism during pilot ejection and developing tolerance limits for injuries sustained under a variety of different vertical acceleration scenarios.