Characterization of combat-related spinal injuries sustained by a US Army Brigade Combat Team during Operation Iraqi Freedom

The top-cited military relevant spine articles

Introduction

Historically musculoskeletal injury has substantially affected United States (US) service members. Lumbosacral spine injuries are among the most common sites of injury for service members across all US military branches and usually presents with pain in the lower back and extremities. The aim of this study is to identify and describe the 50 most-cited articles relevant to military medicine on the subject of the spine.

Methods

In April 2020 Web of Science was used to search the key words: spinal cord injury, spine, thoracic spine, lumbar spine, cervical spine, sacrum, sacral, cervical fusion, lumbar fusion, sacral fracture, combat, back pain, neck pain, and military. Articles published from 1900 to 2020 were evaluated for relevance to military spine orthopaedics and ranked based on citation number. The 50 most-cited articles were characterized based on country of origin, journal of publication, affiliated institution, topic, military branch, and conflict.

Results

1900 articles met search criteria. The 50 most-cited articles were cited 24 to 119 times and published between 1993 and 2017. 30 articles (60%) originated in the United States. Aviation, Space, and Environmental Medicine accounted for the most frequent (n = 10) destination journal followed by Spine (n = 8). 37 institutions contributed to the top 50 most-cited articles. The most common article type was clinically focused retrospective analysis 36% (n = 18), clinically focused cohort study 10% (n = 5), and clinically focused cohort questionnaire, cross-sectional analysis, and randomized study 8% each (n = 4). 90% of articles were non-surgical (n = 45). The US Army had the greatest number of associated articles. Operation Iraqi Freedom and Operation Enduring Freedom were the most-cited conflicts.

Conclusion

The 50 most-cited articles relevant to military spine orthopaedics are predominantly clinically focused, arising from the US, and published in Aviation, Space, and Environmental Medicine, Spine, and The Spine Journal.

Investigating Research Hotspots of Combat-related Spinal Injuries: A 30-year Bibliometric Analysis Study

INTRODUCTION

Spinal cord injuries often lead to significant motor and sensory deficits, as well as autonomic dysfunction. Compared with normal spinal injuries, combat-related spinal injuries (CRSIs) are usually more complex and challenging to treat because of multiple traumas, firing-line treatments, and arduous initial treatments on a battlefield. Yet numerous issues remain unresolved about clinical treatment and scientific research. The enhancement of CRSI diagnosis and treatment quality by military surgeons and nurses is imperative. The objective of this study is to identify the frontiers, hotspots, and trends among recent research, summarize the development process of clinical trials, and visualize them systematically.

MATERIALS AND METHODS

We collected publications from CRSI based on the Core Collection of Web of Science for 30 years from January 1, 1993 to May 1, 2023.Visualizations of the knowledge maps were produced using VOSviewer and CiteSpace software. We examined annual trends of publications and distribution patterns, the number of publications, as well as the research hotspots.

RESULTS

Among 201 documents, it was found that there was a stable upward trend in publications. There were 2 rapid growth stages during the 30 years. Among all countries, the USA contributed the most publications, along with the highest influence and the most international cooperation. Military Medicine was the journal of the maximum publications, whereas the Spine journal was the most influential one. Keyword co-occurrence analysis and trend topics analysis revealed that these articles focused 5 distinct categories for CRSI.

CONCLUSIONS

As the first bibliometric study focused on CRSI, we demonstrated the evolution of the field and provided future research directions. We summarized the hotspots and 5 clusters published. This would serve as a useful guide for clinicians and scientists regarding CRSI global impacts.

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.

Effects of Micromachining on Anti-oxidant Elution from a Mechanically-Adaptive Polymer

Intracortical microelectrodes (IMEs) can be used to restore motor and sensory function as a part of brain-computer interfaces in individuals with neuromusculoskeletal disorders. However, the neuroinflammatory response to IMEs can result in their premature failure, leading to reduced therapeutic efficacy. Mechanically-adaptive, resveratrol-eluting (MARE) neural probes target two mechanisms believed to contribute to the neuroinflammatory response by reducing the mechanical mismatch between the brain tissue and device, as well as locally delivering an antioxidant therapeutic. To create the mechanically-adaptive substrate, a dispersion, casting, and evaporation method is used, followed by a microfabrication process to integrate functional recording electrodes on the material. Resveratrol release experiments were completed to generate a resveratrol release profile and demonstrated that the MARE probes are capable of long-term controlled release. Additionally, our results showed that resveratrol can be degraded by laser-micromachining, an important consideration for future device fabrication. Finally, the electrodes were shown to have a suitable impedance for single-unit neural recording and could record single units in vivo.

Treatment of gunshot wounds of the spine using full-endoscopic surgery: analysis of a small clinical series

Objective. To assess the effectiveness of the treatment of gunshot wounds of the spine using percutaneous full-endoscopic technique.

Material and Methods. Three patients with gunshot shrapnel wounds of the spine were treated using percutaneous full endoscopy.

Results. The patients underwent a removal of foreign bodies (metal fragments) at the cervical, thoracic and lumbosacral levels of the spine using percutaneous full endoscopic surgery. The operations were carried out without complications, with minimal additional trauma to soft tissues and the spinal motion segment. In all three cases, there was a positive dynamics in the form of regression of the pain syndrome. There were no infectious complications.

Conclusion. The successful use of percutaneous full endoscopy in the surgical treatment of blind shrapnel wounds of the spine is shown. The results indicate the expediency of further research and development of this area to address the issue of introducing the technique into the routine practice of treating gunshot wounds both in peacetime in neurosurgical hospitals and centers of spinal neurosurgery, and in wartime at the stages of specialized care.

Human Thoracolumbar Spine Tolerance to Injury and Mechanisms From Caudo-Cephalad Loading: A Parametric Modeling Study

The aims of this investigation were to delineate the internal biomechanics of the spine under vertical impact vector and assess the probability of injury. Male and female whole-body human finite element models were used. The restrained occupants were positioned on the seat, and caudo-cephalad impacts were applied to the base. Different acceleration-time profiles (50-200 ms pulse durations, 11-46 g peak accelerations) were used as inputs in both models. The resulting stress-strain profiles in the cortical and cancellous bones were evaluated at different vertebral levels. Using the peak transmitted forces at the thoracolumbar disc level as the response variable, the probability of injury for the male spine was obtained from experimental risk curves for the various pulses. Results showed that the shorter pulse durations and rise times impart greater loading on the thoracolumbar spine. The analysis of von Mises stress and strain distributions showed that the compression-related fractures are multifaceted with contributions from both the cortical and cancellous bony components of the body. Profiles are provided in the paper. The intervertebral disc may be involved in the fracture mechanism, because it acts as a medium of load transfer between adjacent vertebrae. Injury risks for the shortest pulse was 63%, and for the widest pulse it was close to zero, and injury probabilities for other pulses are given. The present modeling study provides insights into the mechanisms of internal load transfer and describes injury risk levels from caudal to cephalad impacts.

Devastating neurologic injuries in the Syrian war

Background

Since 2011, hundreds of thousands of Syrians have been displaced and injured due to the ongoing Syrian civil war. In this study, we report the prevalence of neurologic injuries in a major rehabilitation center on the Turkish-Syrian border where death and injury tolls continue to rise.

Method

Based on several on-site visits from 2013 to 2016, medical practitioners collected data from patients in the major rehabilitation center on the border of Turkey and Syria. The clinical data, which included the type and cause of injury, laterality, paralysis, areas injured, and treatment offered, were analyzed.

Results

A total of 230 patients were identified as having sustained a neurologic injury, 221/230 (96.1%) male and 9/230 (3.91%) female, ranging from ages 2-52 years. A total of 305 total injuries were documented over the course of a 4-year analysis due to several patients having multiple injuries. Gunshot wounds were the dominant mechanism of injury in 125/230 (54.3%) patients. Patients more frequently sustained single injuries 152/230 (66.1%) than multiple injuries 78/230 (33.9%). Peripheral nerve injuries were the most prevalent injuries, at 92.5% of all neurologic injuries (282/305), specifically injury to the radial nerve, at 19.1% (54/282) of peripheral injuries. Patients with spinal cord injuries made up 20/230 (8.7%) of all patients, with thoracic spine injuries composing 50% (10/20). Traumatic brain injuries were the least prevalent, 3/230 (1.3%), with an equal distribution of subtypes.

Conclusion

This study and critical analysis of the devastation in Syria suggests the desperate need for emergency aid.

Preliminary female cervical spine injury risk curves from PMHS tests

The human cervical spine sustains compressive loading in automotive events and military operational activities, and the contact and noncontact loading are the two primary impact modes. Biomechanical and anatomical studies have shown differences between male and female cervical spines. Studies have been conducted to determine the human tolerance in terms of forces from postmortem human subject (PMHS) specimens from male and female spines; however, parametric risk curves specific to female spines are not available from contact loading to the head-neck complex under the axial mode. This study was conducted to develop female-spine based risk curves from PMHS tests. Data from experiments conducted by the authors using PMHS upright head-spines were combined with data from published studies using inverted head-spines. The ensemble consisted of 20 samples with ages ranging from 29 to 95 years. Except one, all specimens sustained neck injuries, consisting of fractures to cervical vertebrae, and disruptions to the intervertebral disc and facet joints, and ligaments. Parametric survival analysis was used to derive injury probability curves using the compressive force, uncensored for injury and right censored for noninjury data points. The specimen age was used as the covariate. Injury probability curves were derived using the best fit distribution, and the ± 95% confidence interval limits were obtained. Results indicated that age is a significant covariate for injury for the entire ensemble. Peak forces were extracted for 35, 45, and 63 (mean) years of age, the former two representing the young (military) and the latter, the automobile occupant populations. The forces of 1.2 kN and 2.9 kN were associated with 5% and 50% probability of injury at 35 years. These values at 45 years were 1.0 kN and 2.4 kN, and at 63 years, they were 0.7 kN and 1.7 kN. The normalized widths of the confidence intervals at these probability levels for the mean age were 0.74 and 0.48. The preliminary injury risk curves presented should be used with appropriate caution. This is the first study to develop risk curves for females of different ages using parametric survival analysis, and can be used to advance human safety, and design and develop manikins for military and other environments.

Musculoskeletal Injuries in Iraq and Afghanistan: Epidemiology and Outcomes Following a Decade of War

The combined wars in Afghanistan and Iraq represent the longest ongoing conflicts in American military history, with a combined casualty estimate of >59,000 service members. The nature of combat over the last decade has led to precipitous increases in severe orthopaedic injuries, including traumatic amputations and injuries to the spine. Nearly 75% of all injuries sustained in combat now are caused by explosive mechanisms, and fractures comprise 40% of all musculoskeletal injuries. Injuries to the axial skeleton are more frequent among personnel exposed to combat, and spinal trauma is identified in nearly 40% of those killed. Musculoskeletal injuries are expensive and generate some of the highest rates of long-term disability. Noncombat musculoskeletal injuries are endemic within deployed military service members and occur at a greater than threefold rate compared with combat musculoskeletal injuries. Service members with musculoskeletal injuries or behavioral health conditions, such as posttraumatic stress disorder, depression, and psychosis, and those occupying a low socioeconomic status, have an increased risk of inferior outcomes.

Reoperation after in-theater combat spine surgery

BACKGROUND CONTEXT

The ideal timing of surgical decompression or stabilization following combat-related spine injury remains unclear.

PURPOSE

The study aims to determine the etiology and factors related to reoperation following evacuation to the United States after undergoing in-theater spine surgery.

STUDY DESIGN

This is a retrospective analysis.

PATIENT SAMPLE

The sample includes 13 patients with combat-related spine injuries undergoing revision spine surgery.

OUTCOME MEASURES

The outcome measures were time to arrival in the United States, time to reoperation, indications for revision, operative details, further revision surgery, infection rate, complications after reoperation, and most recent clinical follow-up information.

METHODS

This is a retrospective analysis of patients undergoing spine surgery designated as injured during the Global War on Terrorism between July 2003 and July 2013. Inpatient and outpatient medical records, operative reports, and imaging studies were reviewed.

RESULTS

The mean time to index surgery was 1.6 days. The mechanisms of injury included five gunshot wounds, three improvised explosive devices (IED), two helicopter crashes, one motor vehicle accident, and two other mechanisms (fall and crush injury). The mean injury severity score (ISS) was 22.7 (range: 13-45). There were six cervical, seven thoracic, eight lumbar, and two sacral injuries, with a mean of 1.8±1.0 spinal regions injured per patient. Twelve patients had a spinal cord injury, four of which were AIS (American Spinal Association Impairment Scale). Three patients underwent spinal stabilization on the date of injury, and one patient had three separate spine surgeries while downrange before arrival. Four patients underwent fixation in theater. There was a mean of 5.5 days from injury to arrival in the United States, and the mean time to revision fixation was 11.2 days post-index surgery (range: 4-14 days). Revision indications included instability or progressive kyphosis (N=6), and two of these patients had decompression without instrumentation downrange. Other indications included inadequate decompression (N=4), infection, persistent drainage, and epidural hematoma. At a mean of 5.5-year follow-up, all patients were medically retired from service, with minimal neurologic improvement.

CONCLUSIONS

Our study found that instability or progressive kyphosis and incomplete decompression were the most common indications for reoperation after evacuation to the United States. Our data provide additional understanding of the potential etiologies of failure and reoperation following in-theater combat spine surgery, and may help avoid such complications.

Identifying Spinal Injury Patterns in Underbody Blast to Develop Mechanistic Hypotheses

STUDY DESIGN

A retrospective case series of UK victims of blast injury.

OBJECTIVE

To identify the injury patterns in the spine caused by under-vehicle blast, and attempt to derive the mechanism of those injuries.

SUMMARY OF BACKGROUND DATA

The Improvised Explosive Device has been a feature of recent conflicts with frequent attacks on vehicles, leading to devastating injuries. Vehicle design has evolved to reduce the risk of injury to occupants in underbody blast, where the device detonates beneath the vehicle. The mechanism of spinal injury in such attacks is not well understood; understanding the injury mechanism is necessary to produce evidence-based mitigation strategies.

METHODS

A Joint Theatre Trauma Registry search identified UK victims of blast between 2008 and 2013. Each victim had their initial scan reviewed to classify spinal fractures.

RESULTS

Seventy-eight victims were identified, of whom 53 were survivors. There were a total of 284 fractures, including 101 thoracolumbar vertebral body fractures and 39 cervical spine fractures. Most thoracolumbar fractures were wedge compression injuries. Most cervical spine fractures were compression-extension injuries.The most common thoracic and lumbar body fractures in this group suggest a flexed posture at the time of injury. Most cervical spine fractures were in extension, which might be compatible with the head having struck another object.

CONCLUSION

Modifying the seated posture might reduce the risk of thoracolumbar injury, or allow the resulting injury patterns to be controlled. Cervical spine injuries might be mitigated by changing vehicle design to protect the head.

LEVEL OF EVIDENCE

N/A.

Current concepts in penetrating and blast injury to the central nervous system

Aim

To review the current management, prognostic factors and outcomes of penetrating and blast injuries to the central nervous system and highlight the differences between gunshot wound, blast injury and stabbing.

Methods

A review of the current literature was performed.

Results

Of patients with craniocerebral GSW, 66–90 % die before reaching hospital. Of those who are admitted to hospital, up to 51 % survive. The patient age, GCS, pupil size and reaction, ballistics and CT features are important factors in the decision to operate and in prognostication. Blast injury to the brain is a component of multisystem polytrauma and has become a common injury encountered in war zones and following urban terrorist events. GSW to the spine account for 13–17 % of all gunshot injuries.

Conclusions

Urgent resuscitation, correction of coagulopathy and early surgery with wide cranial decompression may improve the outcome in selected patients with severe craniocerebral GSW. More limited surgery is undertaken for focal brain injury due to GSW. A non-operative approach may be taken if the clinical status is very poor (GCS 3, fixed dilated pupils) or GCS 4–5 with adverse CT findings or where there is a high likelihood of death or poor outcome. Civilian spinal GSWs are usually stable neurologically and biomechanically and do not require exploration. The indications for exploration are as follows: (1) compressive lesions with partial spinal cord or cauda equina injury, (2) mechanical instability and (3) complications. The principles of management of blast injury to the head and spine are the same as for GSW. Multidisciplinary specialist management is required for these complex injuries.

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.

Dynamic Responses of Intact Post Mortem Human Surrogates from Inferior-to-Superior Loading at the Pelvis

During certain events such as underbody blasts due to improvised explosive devices, occupants in military vehicles are exposed to inferior-to-superior loading from the pelvis. Injuries to the pelvis-sacrum-lumbar spine complex have been reported from these events. The mechanism of load transmission and potential variables defining the migration of injuries between pelvis and or spinal structures are not defined. This study applied inferior-to-superior impacts to the tuberosities of the ischium of supine-positioned five post mortem human subjects (PMHS) using different acceleration profiles, defined using shape, magnitude and duration parameters. Seventeen tests were conducted. Overlay temporal plots were presented for normalized (impulse momentum approach) forces and accelerations of the sacrum and spine. Scatter plots showing injury and non-injury data as a function of peak normalized forces, pulse characteristics, impulse and power, loading rate and sacrum and spine accelerations were evaluated as potential metrics related to pathological outcomes with the focus of examining the role of the pulse characteristics from inferior-to-superior loading of the pelvis-sacrum-lumbar spine complex. Interrelationships were explored between non-fracture and fracture outcomes, and fracture patterns with a focus on migration of injuries from the hip-only to hip and spine to spine-only regions. Observations indicate that injury to the pelvis and or spine from inferior-to-superior loading is associated with pulse and not just peak velocity. The role of the effect of mass recruitment and injury migration parallel knee-thigh-hip complex studies, suggest a wider application of the recruitment concept and the role of the pulse characteristics.

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).

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).

Incidence and morbidity of concomitant spine fractures in combat-related amputees

BACKGROUND CONTEXT

High-energy blasts are the most frequent cause of combat-related amputations in Operations Iraqi and Enduring Freedom (OIF/OEF). The nondiscriminating effects of this mechanism often result in both appendicular and axial skeletal injuries. Despite this recognized coincident injury pattern, the incidence and consequence of spine fractures in trauma-related combat amputees are unknown.

PURPOSE

This study sought to determine the incidence and morbidity of the associated spine fractures on patients with traumatic lower extremity amputation sustained during OIF/OEF.

STUDY DESIGN/SETTING

Retrospective case control.

PATIENT SAMPLE

Two hundred twenty-six combat-related lower extremity amputees presenting to a single institution and injured between 2003 and 2008 were included for analysis.

OUTCOME MEASURES

Physiologic and functional outcome measures were used to determine the influence of spine fractures on combat amputees. Physiologic measures included intensive care unit (ICU) admission rates, injury severity score (ISS), rate of narcotic/neuropathic pain use, and heterotopic ossification (HO) rates. Functional outcome measures included return-to-duty rates and ambulatory status at final follow-up.

METHODS

Data from 300 consecutive combat-related lower extremity amputations were retrospectively reviewed and grouped. Group 1 consisted of amputees with associated spine fractures, and Group 2 consisted of amputees without spine fractures. The results of the two groups were compared with regard to initial presentation and final functional outcomes.

RESULTS

A total of 226 patients sustained 300 lower extremity amputations secondary to combat-related injuries, the most common mechanism being an improvised explosive device. Twenty-nine of these patients had a spine fracture (13%). Group 1 had a higher ISS than Group 2 (30 vs. 19, p<.001). Group 1 patients were also more likely to be admitted to the ICU (86% vs. 46%, p<.001). Furthermore, Group 1 patients had a significantly higher rate of HO in their residual limbs (82% vs. 55%, p<.005).

CONCLUSIONS

The incidence of spine fractures in combat-related amputees is 13%. The results suggest that combat-related amputees with spine fractures are more likely to sustain severe injuries to other body systems, as indicated by the significantly higher ISS and rates of ICU admission. This group also had a significantly higher rate of HO formation, which may be attributable to the greater local and/or systemic injuries sustained by these patients.

Spinal injuries in United States military personnel deployed to Iraq and Afghanistan: an epidemiological investigation involving 7877 combat casualties from 2005 to 2009

STUDY DESIGN

Retrospective analysis of a prospective data set.

OBJECTIVE

Determine the incidence and epidemiology of combat-related spinal injuries for the wars in Afghanistan and Iraq.

SUMMARY OF BACKGROUND DATA

Recent studies have identified a marked increase in the rate of combat-related spine trauma among casualties in Afghanistan and Iraq. Limitations in these previous works, however, limit their capacity for generalization.

METHODS

A manual search of casualty records stored in the Department of Defense Trauma Registry was performed for the years 2005 to 2009. Demographic information, nature of spinal wounding, injury mechanism, concomitant injuries, year, and location of injury were recorded for all soldiers identified as having sustained combat-related spine trauma. Incidence rates were constructed by comparing the frequencies of spine casualties against defense manpower deployment data. Multivariate Poisson regression was used to identify statistically significant factors associated with spinal injury.

RESULTS

In the years 2005 to 2009, 872 (11.1%) casualties with spine injuries were identified among a total of 7877 combat wounded. The mean age of spine casualties was 26.6 years. Spine fractures were the most common injury morphology, comprising 83% of all spinal wounds. The incidence of combat-related spinal trauma was 4.4 per 10,000, whereas that of spine fractures was 4.0 per 10,000. Spinal cord injuries occurred at a rate of 4.0 per 100,000. Spinal cord injuries were most likely to occur in Afghanistan (incident rate ratio: 1.96; 95% confidence interval: 1.68-2.28), among Army personnel (incident rate ratio: 16.85; 95% confidence interval: 8.39-33.84), and in the year 2007 (incident rate ratio: 1.90; 95% confidence interval: 1.55-2.32). Spinal injuries from gunshot were significantly more likely to occur in Iraq (17%) than in Afghanistan (10%, P = 0.02).

CONCLUSION

The incidence of spine trauma in modern warfare exceeds reported rates from earlier conflicts. The study design and population size may enhance the capacity for generalization of our findings.

LEVEL OF EVIDENCE

3.

Cervical spine injury biomechanics: Applications for under body blast loadings in military environments

BACKGROUND

While cervical spine injury biomechanics reviews in motor vehicle and sports environments are available, there is a paucity of studies in military loadings. This article presents an analysis on the biomechanics and applications of cervical spine injury research with an emphasis on human tolerance for underbody blast loadings in the military.

METHODS

Following a brief review of published military studies on the occurrence and identification of field trauma, postmortem human subject investigations are described using whole body, intact head-neck complex, osteo-ligamentous cervical spine with head, subaxial cervical column, and isolated segments subjected to differing types of dynamic loadings (electrohydraulic and pendulum impact devices, free-fall drops).

FINDINGS

Spine injuries have shown an increasing trend over the years, explosive devices are one of the primary causal agents and trauma is attributed to vertical loads. Injuries, mechanisms and tolerances are discussed under these loads. Probability-based injury risk curves are included based on loading rate, direction and age.

INTERPRETATION

A unique advantage of human cadaver tests is the ability to obtain fundamental data to delineate injury biomechanics and establish human tolerance and injury criteria. Definitions of tolerances of the spine under vertical loads based on injuries have implications in clinical and biomechanical applications. Primary outputs such as forces and moments can be used to derive secondary variables such as the neck injury criterion. Implications are discussed for designing anthropomorphic test devices that may be used to predict injuries in underbody blast environments and improve the safety of military personnel.

The nature and incidence of musculoskeletal combat wounds in Iraq and Afghanistan (2005-2009)

OBJECTIVES

This investigation sought to describe orthopaedic wounds sustained by service members deployed to Iraq or Afghanistan from 2005 to 2009.

DESIGN

Retrospective review of prospective data.

SETTING

: Joint Theater Trauma Registry (JTTR).

PATIENTS

The 6092 musculoskeletal casualties contained in the JTTR.

INTERVENTION

The JTTR was queried to identify all personnel sustaining musculoskeletal injuries in the period 2005-2009. Demographic information, injury mechanism, and nature of wounds were determined for all individuals. Deployment data for all service members were obtained through the Defense Manpower Data Center and the incidence of orthopaedic injuries and wounding patterns was assessed.

MAIN OUTCOME MEASUREMENTS

Pairwise comparisons were made to identify statistically significant differences in incidence, and significant associations, between injury mechanism and injuries/wounding patterns.

RESULTS

The JTTR contained data on 6092 musculoskeletal casualties with 17,177 wounds. Seventy-seven percent of all casualties sustained a musculoskeletal wound. The incidence of musculoskeletal combat casualties was 3.06 per 1000 deployed personnel per year, with fractures occurring in 3.41 per 1000 and soft-tissue wounds most commonly encountered (4.04 per 1000). Amputations represented 6% of all combat wounds. Most musculoskeletal wounds were caused by explosive blast (P < 0.001), as were nearly all traumatic amputations.

CONCLUSIONS

This study represents the most complete description of the scope of orthopaedic war trauma. It also presents injury-specific incidences that have not previously been described for musculoskeletal combat casualties. Musculoskeletal casualties may occur in 3 of every 1000 personnel deployed per year.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

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.

Evaluation and management of combat-related spinal injuries: a review based on recent experiences

BACKGROUND CONTEXT

The current approach to the evaluation and treatment of military casualties in the Global War on Terror is informed by medical experience from prior conflicts and combat encounters from the last 10 years. In an effort to standardize the care provided to military casualties in the ongoing conflicts, the Department of Defense (DoD) has published Clinical Practice Guidelines (CPGs) that deal specifically with the combat casualty sustaining a spinal injury. However, the combat experience with spine injuries in the present conflicts remains incompletely described.

PURPOSE

To describe the CPGs for the care of the combat casualty with suspected spine injuries and discuss them in light of the published military experience with combat-related spinal trauma.

STUDY DESIGN

Literature review.

METHODS

A literature review was conducted regarding published works that discussed the incidence, epidemiology, and management of combat-related spinal trauma. The CPGs, established by the DoD, are discussed in light of actual military experiences with spine trauma, the present situation in the forward surgical teams and combat support hospitals treating casualties in theater, and recent publications in the field of spine surgery.

RESULTS

In the conventional wars fought by the United States between 1950 and 1991 (Korea, Vietnam, Gulf War I), the incidence of spine injuries remained close to 1% of all combat casualties. However, in the Global War on Terror, the enemy has relied on implements of asymmetric warfare, including sniper attacks, ambush, roadside bombs, and improvised explosive devices. The increase in explosive mechanisms of injury has elevated the number of soldiers exposed to blunt force trauma and, consequently, recent publications reported the highest incidence of combat-related spinal injuries in American military history. Wounded soldiers are expeditiously evacuated through the echelons of care but typically do not receive surgical management in theater. The current CPGs for the care of soldiers with combat-related spinal injuries should be re-examined in light of data regarding the increasing number of spine injuries, new injury patterns, such as lumbosacral dissociation and low lumbar burst fractures, and recent reports within the field of spine surgery as a whole.

CONCLUSIONS

American and coalition forces are sustaining the highest spine combat casualty rates in recorded history and previously unseen injuries are being encountered with increased frequency. While the CPGs provide useful direction in terms of the evaluation and management of combat casualties with spine injuries, such recommendations may warrant periodic re-evaluation in light of recent combat experiences and evolving scientific evidence within the spine literature.

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.

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.