TY - JOUR
AU - Loftis, Kathryn L
AB - Abstract A recent study of all mounted vehicle underbody blast attacks found that 21% of Abbreviated Injury Scale Severity 2+ injuries in the Joint Trauma Analysis and Prevention of Injury in Combat network were injuries to the leg and ankle. To develop effective countermeasure systems for these attacks, the epidemiology and mechanisms of injury from this loading environment need to be quantified. The goal of this study was to develop a military correlate of an existing civilian case review framework, the Crash Injury Research and Engineering Network (CIREN), to consider the differences in military event types and the amount of available vehicle/attack information. Additional data fields were added to the CIREN process to cover military-specific data and “certainty” definitions in the proposed injury hypothesis were modified. To date, six group reviews have been conducted analyzing 253 injuries to the foot/ankle, tibia, femur, pelvis, and lumbar spine from 52 occupants. The familiar format and unclassified nature of the presentations allowed for the involvement of biomechanics experts from multiple disciplines. Under body blast, BioTab, CIREN INTRODUCTION In the conflicts in Iraq and Afghanistan, injury to the extremities occurred in approximately 80% of all battlefield attacks. Of the extremity injuries, fractures represented 26% of the total.1 Additionally, the prevalence of improvised explosive devices resulted in an increase in the number of Underbody Blast (UBB) attacks. A recent study of all mounted occupants in vehicle UBB attacks found that 21% of Abbreviated Injury Scale (AIS) severity 2+ injuries in the Joint Trauma Analysis and Prevention of Injury in Combat (JTAPIC) network were injuries to the leg and ankle.2 To develop effective countermeasure systems for these attacks, the epidemiology and causes of injury need to be documented. There are multiple studies that document the overall incidence of injury caused by explosions; however, these are broad injury descriptions and they do not specify underbody blast or cause of injury.3–6 There are a limited number of studies that investigate only UBB attacks but these studies also don’t provide the cause of injury.7,8 A case review methodology can identify potential causes of injury that can be replicated in a laboratory environment. The automotive safety community uses a defined methodology to conduct case reviews of real-world crash events to determine injury mechanism.9 These reviews are compiled in the Crash Injury Research and Engineering Network (CIREN) by the National Highway Traffic Safety Administration. The end goal for each of these case reviews is a BioTab, a structured record that describes the hypothesized injury mechanisms using set datafields.9 The BioTab methodology is a standard form that is familiar to injury biomechanics researchers; therefore, a military case review that leverages the automotive format would facilitate military injury mechanism discussion. Fundamental differences in the military environment and loading regime required modification of the CIREN BioTab. Another component of the case review process that had to be replicated is collaboration between clinicians, injury biomechanics researchers, and vehicle designers. Each of these groups has a unique and important point of view to be considered during discussions of how the injuries occurred with the intent to prevent these injuries in the future. The goal of this study was to develop a military BioTab and case review correlate from the existing civilian framework. METHODS BioTab Development Each field in the civilian BioTab was examined to revise language and fields based on its applicability to coding a military event. Just as an automotive crash has standard data fields, the military cases had similar standard fields. For each occupant, the following data fields were collected, when available.  - Event data: estimated blast size, overmatch status (blast size in relation to vehicle design), size of the blast crater, vehicle motion, road type, and road configuration.  - Vehicle data: vehicle type, vehicle damage, vehicle roll-over status, seat data (mounting, energy attenuation, stirrups), floor energy attenuation, location of the blast relative to the occupant, general vehicle layout, vehicle intrusion, occupant distribution.  - Occupant data: height, weight, age, sex, occupant position, occupant restraint status, AIS 2005 Update 2008 injury codes,10 images (CT scan, X-Ray, and magnetic resonance imaging), radiologist reports, other occupants, occupant restraint and personal protective equipment (PPE) status, PPE type, and PPE damage. After collection of the available data fields, the civilian BioTab was revised to include evidence and parameters specific to military UBB events. For the Injury Causation Scenario (ICS), much of the language was the same as the CIREN format, with the addition of a new source of energy: underbody blast. The ICS is the overall description of how the researchers thought the injury occurred. An example would be a calcaneus fracture due to the foot in contact with the rapidly deforming floor during underbody blast loading. The UBB was added so injuries could be attributed to the initial acceleration due to the blast. New ICS evidence fields and definition clarifications are listed below. Improper restraint use: Was there evidence of improper restraint use that caused this injury? Example: An occupant not attaching all belts in a five-point restraint system resulting in increased pelvis excursion. Non-optimal posture: Was there evidence the occupant was positioned in a way that caused the injury or resulted in increased severity? Example: An occupant that was lying across bench seats instead of seated in an upright posture. Vehicle dynamics: Was there evidence of vehicle motion that would have caused the injury (or increased the severity) or do the vehicle dynamics support the proposed ICS? Example: A roll-over case with neck injury due to roof strike or vertical load injury in UBB. Road conditions: Was there evidence that the condition of the road (i.e., smooth pavement versus rough, unpaved road) would have contributed to the injury? Increased excursion of unbelted occupant: Was there evidence of increased excursion due to unbelted status that caused or increased the severity of this injury? Example: An unbelted occupant with neck injury due to roof strike. The involved physical component (IPC) section only required minor revisions from the CIREN format. This field defines the vehicle component that is hypothesized to have interacted with the occupant. Using the same calcaneus example from above, the IPC would be the floor in that case. The IPC evidence parameters and definitions were adjusted to better reflect the military evidence that may be available from theater, but interior vehicle components were fairly standard between civilian and military. The fields that were revised or added were: Inferred contact: Was the component contact inferred? For the contact to be inferred, the case review team thought the occupant contacted a vehicle component based on the proposed injury causing scenario but there was no photographic evidence of a contact. This field is only populated if the answer is yes. In civilian automotive cases with extensive documentation of the vehicle interior, this field is less commonly used. For the military cases, the answer is frequently “yes” for this question due to lack of physical evidence of contact from vehicle investigation and pictures. Short/Tall Stature: Does the occupant anthropometry support the hypothesized IPC? There were no set values for stature, this section was marked based on engineering judgment combined with knowledge of the specific vehicle’s occupant space. In practice, it was infrequently selected. Example: A very tall occupant with neck injury and hypothesized roof interaction due to their height. This field was more relevant for the military cases because space inside the military vehicles is often tight, so there was a hypothesis that head/neck injuries could be caused by contact with the interior roof due to reduced headspace. Pre-impact movement: Does the pre-impact motion of the vehicle support the proposed IPC? Occupant proximity to IPC: Is the occupant in a position that predisposes them to IPC contact? This was also a more relevant evidence field for the military cases because some seating positions are surrounded by equipment in close proximity to the occupant, unlike standard civilian vehicles. Contributing factors were maintained from the civilian BioTab and some fields were added or the definition was expanded, as shown below. For all of these fields, the description of “contributed to the injury” encompasses the contribution of the defined parameter to the occurrence of the injury or a change in the severity of the injury. Age: Does the age of the occupant contribute to the injury? For military injury tracking purposes, this was marked for ages over 35 because of the generally young military population. It was also noted if age was believed to have contributed to the injury. In practice, this field served as a tracking variable and there were no cases where an injury was attributed to age. Comorbidity: Does the occupant have existing comorbidities that contributed to the injury? This information was often unavailable for the military occupants. Proximity to source of energy (SOE): Does the occupant’s proximity to the source of energy contribute to the injury? In many cases, this was established by examining the injuries of the other occupants in the vehicle, as well as analyzing the blast location versus the seating position of the military occupant. Unbelted case occupant: Does the occupant sustain a different or more serious injury than expected because they were unbelted? For the military cases, the seatbelt or harness system was assumed to be properly worn unless it was specifically stated otherwise. Improper PPE use: Does improper PPE use contribute to the injury? For the military cases, PPE use was assumed to be properly worn unless there was evidence otherwise. Large threat size: Are the injuries different or more severe because this blast was larger? For the current study, the threat size was estimated in theater and checked by comparing vehicle damage from theater to an event with a known size. This parameter can be changed based on the scope of the dataset analyzed. For the current dataset, a large threat size indicated that it was larger than the expected threat for the vehicle testing using the Warrior Injury Assessment Manikin (WIAMan) but still not so large that the vehicle lost structural integrity. Intrusion: Did intrusion contribute to the injury? Intrusion was defined as any deformation of the vehicle material that resulted in a portion of the vehicle deforming into the occupant space. An example would be a vehicle foot well that deforms upward by 5 cm. The existence and magnitude of intrusion were often difficult to determine. Hull breach: Did vehicle hull breach (a hole through the outer surface into the occupant compartment of the vehicle) contribute to the injury? Hull breach can occur with or without intrusion. Secondary rollover: Did the vehicle experience a roll-over after the blast event that contributed to the injury? Loose cargo: Did the occupant’s interaction with loose cargo contribute to the injury? A new section was added to the military cases to capture information about the mitigating factors that were available for the occupant. Definitions and examples are below. Seat: Description of the vehicle/seat interface and the type of energy attenuation mechanism of the seat, if available. Floor: Description of the floor type and energy attenuation mechanisms. Foot stirrups: Were foot stirrups, a device to get feet off the floor, available? Helmet type: What helmet was the occupant wearing at the time of injury? Helmet: Helmet damage that would support the ICS or injury mechanism. Other (specify): Any other energy mitigating systems available for occupant protection that were pertinent to the injury. For the injury mechanism section of the BioTab, no changes were made from the CIREN format.9 Compared to the detailed vehicle documentation in CIREN, the military vehicle information was severely limited due to the austere and often hostile environment encountered during data collection. To provide a range of uncertainty values, the CIREN confidence definitions were modified to allow for a larger range of confidence levels in the military case reviews. Specifically, for military cases contact evidence could be inferred for certain and probable confidence. This was a subjective assessment by the case review team but derived by group consensus. Cases where the confidence was high were generally straight forward injuries similar to those the researchers were familiar with based on their automotive injury expertise or experimental testing. As an example, floor loading of the foot resulting in calcaneus fracture with a regional compressive mechanism has been demonstrated experimentally.11 Cases that had a more complex loading environment generally resulted in a lower confidence level. Upper extremity injuries generally have lower confidence because of the increased excursion and the variety of structural interaction. Case Review Process After development of the military BioTab, it was applied to military UBB cases that were gathered by the JTAPIC program. The case reviews were developed with two levels of releasability (classified and limited release). The classified version allowed qualified participants to see details about the attack and vehicle damage. The limited release version was created to relay pertinent information to academic partners without disclosing vehicle vulnerabilities. The case reviews started with an overview slide that included a general vehicle and occupant injury diagrams.12 This slide presented seating position relative to the blast, other occupant locations, and the general pattern of injuries (Fig. 1). The vehicle diagram was simplified to relay as much information as possible to the academic partners without disclosing sensitive information. FIGURE 1. Open in new tabDownload slide General vehicle illustration (A) and a VisualAID injury diagram (B). Both of these are based on a notional case and are for illustration purposes only. (UNK, unknown; RTD, return to duty; LTD, limited duty; KIA, killed in action). Following the overview slide, a full listing of all recorded occupant injuries was included. Injuries that were an AIS 1 or 2 were not reviewed with a formal case review unless they involved a fracture. Cases with no radiological evidence or vehicle information were not reviewed. Just as CIREN utilized a multidisciplinary group to review cases, the military BioTab coding and review involved expertise from multiple groups. Using the details from the military case, the injury lists, and biomechanics knowledge, each relevant injury was coded with the new military BioTab structure to record the injury mechanism. RESULTS Using this novel military BioTab format (Appendix A) to record injury mechanism and causation, military cases were formally reviewed for the first time. To date, six group reviews have been conducted analyzing 52 occupants with 253 injuries to the foot/ankle, tibia, femur, pelvis, and lumbar spine, the most commonly injured body regions. From these injuries, 221 biotabs were completed. The 32 injuries without a biotab fell into the following groups: no radiology was provided, the provided radiology did not show the injury, it was a low severity injury (i.e., ankle sprain), or it was a transverse process fracture in the spine. The biotab confidence distribution for the ICS included six cases with a “certain,” 167 with “probable,” and 45 with “possible” out of 221 BioTabs. The expertise represented by the case review participants included:  - Warfighter injury biomechanics and survivability (Warrior Injury Assessment Manikin [WIAMan] Engineering Office, Army Research Laboratory [ARL] Warfighter Survivability Branch).  - Military vehicle capabilities (ARL Engineering Assessment Branch).  - Military safety systems (Tank Automotive Research Development and Engineering Center, Diversified Technical Systems, Inc).  - Injury biomechanics and automotive safety (Academic partners: Applied Physics Laboratory of Johns Hopkins, Duke University, Medical College of Wisconsin, the Ohio State University, Virginia Tech, University of Michigan, University of Virginia, Wake Forest University, Wayne State)  - Orthopedic injury and medical expertise (academic partners: Wake Forest University). DISCUSSION The necessity of providing limited vehicle information for security purposes made it difficult for academic partners to understand the vehicle damage and potential occupant interactions. To better understand the military vehicle environment, ARL sponsored a static display to allow researchers to view and interact with military vehicles. The standard in-theater Warfighter PPE was provided to demonstrate the size and weight of the additional equipment worn in the military vehicles. Every effort should be made to have additional academic partners with the necessary clearance to view the full, classified dataset for future case reviews. The relative lack of familiarity of the academic researchers with military vehicles (compared to their knowledge of civilian automobiles) was also compensated for by involving ARL’s military vehicle specialists. These individuals were able to provide insight into the protection systems of the vehicle involved in the event. These experts were also able to assess how the events compared to vehicle design evaluations. The lack of information about an event was considered a limitation for these cases studies. Unlike the civilian environment, there were many factors that contributed to reduced information from the vehicles. As an example, no standard photographs of the damaged vehicles were taken to support this research study. In the CIREN cases, there is a standard set of photographs to document vehicle information. Even with the increased level of uncertainty, there were only two events that resulted in an “unknown” code for the injury causation scenario in three BioTabs. Therefore, the reduced level of information did not contribute to a large number of cases with unknown injury causation scenarios. Given that over 78% of the coded BioTabs had a “probable” or greater confidence level, this method of recording injury mechanism is useful for investigating military injury scenarios, even given the reduced information that is available. Another finding of this study was that while the fracture patterns were qualitatively different compared to automotive injuries, many of the regional mechanisms of injury were similar. This similarity and the relatively simplistic regional mechanisms of injury contributed to the ability of the case review group to classify the majority of the cases with a probable or certain level of certainty. For future work, the results from these case reviews can be used to inform experimental testing. These laboratory test configurations can be used to verify that the causes of injury determined in the BioTab can be replicated in the lab. Also, the fracture patterns from these experiments can be compared to the in-theater occupants to determine if the resulting lab injuries are similar to the experimental tests. CONCLUSIONS A military version of BioTab was created and refined through collaborative case reviews, which included the revision and addition of fields from the existing civilian BioTab. The familiar format and unclassified nature of the presentations allowed for involvement of biomechanics experts from multiple disciplines. The creation of a military BioTab has led to the identification of critical injury mechanisms for Warfighters exposed to an UBB attack. This data collection tool can be used to assess injury mechanism in military vehicles for any project in the future to further the understanding of military injury mechanisms. Supplementary Material Supplementary material is available at Military Medicine online. Previous Presentations Presented as a poster at the 2017 Military Health System Research Symposium, August 2017, Kissimmee, FL; abstract # MHSRS-17-1731. Funding WIAMan Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-14-2-0053. This supplement was sponsored by the Office of the Secretary of Defense for Health Affairs. Acknowledgments We would like to acknowledge the assistance and data provided by the Joint Trauma Analysis and Prevention of Injury in Combat, which allowed for the completion of injury mechanism analysis. WIAMan Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-14-2-0053. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. References 1 Loftis KL , Gillich PJ: Trauma comparison of civilian automotive with military combat injuries. Short Communications from AAAM’s 58th Annual Scientific Conference . Traffic Inj Prev 2014 ; 15 ( sup1 ): S238 – -S269 . Google Scholar Crossref Search ADS PubMed WorldCat 2 Owens BD , Kragh JF Jr., Wenke JC, Macaitis J, Wade CE, Holcomb JB: Combat wounds in operation Iraqi Freedom and operation Enduring Freedom . J Trauma Acute Care Surg 2008 ; 64 ( 2 ): 295 – 299 . Google Scholar Crossref Search ADS WorldCat 3 Belmont P.J. , Schoenfeld A.J., Goodman G: Epidemiology of combat wounds in Operation Iraqi Freedom and Operation Enduring Freedom: orthopaedic burden of disease . J Surg Orthop Adv 2010 ; 19 : 2 – 7 . Google Scholar PubMed OpenURL Placeholder Text WorldCat 4 Dougherty A.L. , Mohrle C.R., Galarneau M.R., Woodruff S.I., Dye J.L., Quinn K.H: Battlefield extremity injuries in Operation Iraqi Freedom . Injury 2009 ; 40 : 772 – 777 . Google Scholar Crossref Search ADS PubMed WorldCat 5 Johnson B.A. , Carmack D., Neary M., Tenuta J., Chen J: Operation Iraqi Freedom: the Landstuhl Regional Medical Center experience . J Foot Ankle Surg 2005 ; 44 : 177 – 183 . Google Scholar Crossref Search ADS PubMed WorldCat 6 Owens B.D. , Kragh J.F. Jr., Wenke J.C., Macaitis J., Wade C.E., Holcomb J.B: Combat wounds in operation Iraqi Freedom and operation Enduring Freedom . J Trauma 2008 ; 64 ( 2 ): 295 – 299 . Google Scholar Crossref Search ADS PubMed WorldCat 7 Alvarez J. ( 2011 ) Epidemiology of blast injuries in current operations. In RTO-MP-HFM-207- Survey of Blast Injury across the Full Landscape of Military Science. In: Proceedings of RTO Human Factors and Medicine Panel (HFM) Symposium, Halifax, Nova Scotia, October 3–5. 8 Vasquez K.B. , Brozoski F.T., Logsdon K.P., Chancey V.C: Retrospective analysis of injuries in underbody blast events: 2007–2010 . Mil Med 2018 ; 183 ( suppl_1 ): 347 – 352 . Google Scholar Crossref Search ADS PubMed WorldCat 9 Schneider LW , Rupp JD, Scarboro M, et al. : BioTab – a new method for analyzing and documenting injury causation in motor-vehicle crashes . Traffic Inj Prev 2011 ; 12 ( 3 ): 256 – 265 . Google Scholar Crossref Search ADS PubMed WorldCat 10 Association for the Advancement of Automotive Medicine . Abbreviated Injury Scale 2005 Update 2008. Barrington, Illinois, Association for the Advancement of Automotive Medicine, 2008 . 11 Danelson K.A. , Kemper A.R., Mason M.J, et al. : Comparison of ATD to PMHS response in the under-body blast environment. Stapp Car Crash J 2015 ; 59 : 445 – 520 . Google Scholar PubMed OpenURL Placeholder Text WorldCat 12 Kulaga AR , Gillich PJ: Investigation Of Integrating Three-Dimensional (3-D) Geometry Into The Visual Anatomical Injury Descriptor (Visual AID) Using WebGL, Summer Research Technical Report, Survivability/Lethality Analysis Directorate, U.S. Army Research Laboratory, Aberdeen Proving Ground, August, 2011 . Available at www.dtic.mil/get-tr-doc/pdf?AD=ADA558601; accessed April 6, 2018. Author notes The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. Published by Oxford University Press on behalf of Association of Military Surgeons of the United States 2019. This work is written by (a) US Government employee(s) and is in the public domain in the US. Published by Oxford University Press on behalf of Association of Military Surgeons of the United States 2019.
TI - A Military Case Review Method to Determine and Record the Mechanism of Injury (BioTab) from In-Theater Attacks
JF - Military Medicine
DO - 10.1093/milmed/usy396
DA - 2019-03-01
UR - https://www.deepdyve.com/lp/oxford-university-press/a-military-case-review-method-to-determine-and-record-the-mechanism-of-mUzXQSbcw3
SP - 374
EP - 378
VL - 184
IS - Supplement_1
DP - DeepDyve
ER -