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Background: Thoracic surgery constitutes 2.5% of surgical procedures performed in theater, but the skills required are increasingly foreign to military surgeons. This study examines thoracic surgical workload in Iraq and Afghanistan to help define surgical training gaps., Methods: Retrospective analysis of Department of Defense Trauma Registry for all role 2 (R2) (forward surgical) and role 3 (R3) (theater) military facilities, from January 2002 to May 2016. The 95 thoracic surgical International Classification of Diseases-9th Rev.-Clinical Modification procedure codes were grouped into 10 categories based on anatomy or endoscopy. Select groups were further stratified by type of definitive procedure. Procedure groupings were determined and adjudicated by surgeon subject matter experts. Data analysis used Stata Version 15 (College Station, TX)., Results: Of the total procedures, 5,301 were classified as thoracic surgical procedures and were included in the present study. The majority of thoracic surgical procedures (4,645 [87.6%]) were recorded as being performed at R3 medical treatment facilities (MTFs). The thoracic surgical procedures groups with the largest proportions were: bronchoscopy (39.1%), thoracotomy (16.9%), diaphragm (15.6%), and lung (11.4%). The most common lung procedure subgroup, aside from not otherwise specified, was segmentectomy (28.8%). The R3 MTFs recorded nearly five times the number of lung procedures compared with R2 MTFs; with R3 MTFs recording more than eight times the number of lobectomies compared with R2 MTFs. Thoracic workload was variable over the 15-year study period., Conclusion: Thoracic surgical skills are necessary in the deployed environment to manage combat-related injuries. Given the current trends in training and specialization, development and sustainment of thoracic surgical skills is challenging in the deployed US trauma system and likely for other nations, and humanitarian surgical care as well. Current training and practice paradigms pose both training and sustainment challenges for surgeons who deploy to a combat zone., Level of Evidence: Therapeutic/Care Management IV.

Under direction from the Defense Health Agency, subject matter experts (SMEs) from the Joint Trauma System, Armed Forces Medical Examiner System, and civilian sector established the Military Trauma Mortality Review process. To establish the most empirically robust process, these SMEs used both qualitative and quantitative methods published in a series of peer-reviewed articles over the last 3 years. Most recently, the Military Mortality Review process was implemented for the first time on all battle-injured service members attached to the United States Special Operations Command from 2001 to 2018. The current Military Mortality Review process builds on the strengths and limitations of important previous work from both the military and civilian sector. To prospectively improve the trauma care system and drive preventable death to the lowest level possible, we present the main misconceptions and lessons learned from our 3-year effort to establish a reliable and sustainable Military Trauma Mortality Review process. These lessons include the following: (1) requirement to use standardized and appropriate lexicon, definitions, and criteria; (2) requirement to use a combination of objective injury scoring systems, forensic information, and thorough SME case review to make injury survivability and death preventability determinations; (3) requirement to use nonmedical information to make reliable death preventability determinations and a comprehensive list of opportunities for improvement to reduce preventable deaths within the trauma care system; and (4) acknowledgment that the military health system still has gaps in current infrastructure that must be addressed to globally and continuously implement the process outlined in the Military Trauma Mortality Review process in the future. LEVEL OF EVIDENCE: Level III.

Background: Motor vehicle-related (MVR) incidents are important causes of morbidity among deployed US service members (SMs). Nonbattle MVR injuries are usually similar to civilian MVR injuries, while battle MVR injuries are often unique due to the blast effects from precipitating explosive mechanisms. Our primary objective was to describe the characteristics and trends of nonfatal MVR injuries sustained by deployed US SMs. A second objective was to assess the association between mechanism of injury (i.e., explosive vs. nonexplosive) and limb amputation., Methods: We conducted a retrospective cross-sectional analysis using data from the Department of Defense Trauma Registry collected from October 2001 to December 2018. Descriptive statistics were reported stratified by mechanism of injury (explosive vs. nonexplosive). The association between mechanism of injury and limb amputation was assessed using logistic regression models., Results: There were 3,119 US casualties who sustained nonfatal MVR injuries, 2,380 (76.3%) SMs sustained nonexplosive MVR injuries while 739 (23.7%) sustained explosive MVR injuries. Of all MVR casualties, 2,085 (66.9%) were in Iraq or Syria and 1034 (33.1%) in Afghanistan. The annual prevalence of nonfatal MVR battle casualties was highest in Iraq and Syria from 2003 to 2009 and Afghanistan from 2009 to 2014, ranging overall 15 to 50 MVR casualties per 1,000 wounded in action. There were 92 limb amputations associated with MVR incidents. Compared with nonexplosive MVR mechanisms, explosive MVR mechanisms had higher association with limb amputation (adjusted odds ratio, 2.6; confidence interval, 1.7-3.9), even after adjusting for injury year and Injury Severity Score (AOR, 2.1; confidence interval: 1.4-3.4)., Conclusion: Motor vehicle-related incidents are an important cause of injury in US military operations. Compared with nonexplosive MVR incidents, explosive MVR incidents result in more severe injuries, and have a higher associated risk of limb amputation. Continued efforts to improve injury prevention through protective equipment and medical training specific to MVR injuries are needed., Level of Evidence: Prognostic and epidemiological study, Level III.

Background: Timely and optimal care can reduce mortality among critically injured combat casualties. US military Role 2 surgical teams were deployed to forward positions in Afghanistan on behalf of the battlefield trauma system. They received prehospital casualties, provided early damage control resuscitation and surgery, and rapidly transferred casualties to Role 3 hospitals for definitive care. A database was developed to capture Role 2 data., Methods: A retrospective review and descriptive analysis were conducted of battle-injured casualties transported to US Role 2 surgical facilities in Afghanistan from February 2008 to September 2014. Casualties were analyzed by mortality status and location of death (pretransport, intratransport, or posttransport), military affiliation, transport time, injury type and mechanism, combat mortality index-prehospital (CMI-PH), and documented prehospital treatment., Results: Of 9,557 casualties (median age, 25.0 years; male, 97.4%), most (95.1%) survived to transfer from Role 2 facility care. Military affiliation included US coalition forces (37.4%), Afghanistan National Security Forces (23.8%), civilian/other forces (21.3%), Afghanistan National Police (13.5%), and non-US coalition forces (4.0%). Mortality differed by military affiliation (p < 0.001). Among fatalities, most were Afghanistan National Security Forces (30.5%) civilian/other forces (26.0%), or US coalition forces (25.2%). Of those categorized by CMI-PH, 40.0% of critical, 11.2% of severe, 0.8% of moderate, and less than 0.1% of mild casualties died. Most fatalities with CMI-PH were categorized as critical (66.3%) or severe (25.9%), whereas most who lived were mild (56.9%) or moderate (25.4%). Of all fatalities, 14.0% died prehospital (pretransport, 5.8%; intratransport, 8.2%), and 86.0% died at a Role 2 facility (posttransport). Of fatalities with documented transport times (median, 53.0 minutes), most (61.7%) were evacuated within 60 minutes., Conclusions: Role 2 surgical team care has been an important early component of the battlefield trauma system in Afghanistan. Combat casualty care must be documented, collected, and analyzed for outcomes and trends to improve performance., Level of Evidence: Therapeutic/Care Management, level IV.

Background: Approximately 4.5% of surgical procedures performed at Role 2 (R2) (forward surgical) and Role 3 (R3) (theater) medical treatment facilities can be classified as neurosurgical. These procedures are foreign to the routine daily practice of the military general surgeon. The purpose of this study was to examine the neurosurgical workload in Iraq and Afghanistan in order to inform the future predeployment neurosurgical training needs of nonneurosurgical providers., Methods: Retrospective analysis of the Department of Defense Trauma Registry for all R2 and R3 medical facilities, from January 2002 to May 2016. The 103 neurosurgical International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes identified were grouped by anatomic location. Select groups were further subdivided. Data analysis used Stata version 14 (College Station, TX)., Results: A total of 7,509 neurosurgical procedures were identified. The majority (7,244 [96.5%]) occurred at R3 theater hospitals. Cranial procedures were the most common at both R2 (120, 45.3%) and R3 (4,483 [61.9%]), with craniotomy/craniectomy the most frequent procedure. Spine procedures were performed almost exclusively at R3, with 61.1% being fusions/stabilizations and 26.9% being spinal decompression alone. Neurosurgical caseload was variable over the 15-year study period, dropping to almost zero in 2016., Conclusions: Neurosurgical procedures were performed primarily at larger R3 theater hospitals where neurosurgeons were assigned if present in theater; however, more than 100 cranial procedures were performed at forward R2 where neurosurgeons were not deployed. Considering that neurosurgeons are not everywhere available within the war zone, deploying general surgeons should have familiarity with trauma neurosurgery., Level of Evidence: Epidemiologic study, level III; Care Management, level IV.

Background: Vascular surgery constitutes approximately 6.5% of surgical procedures performed for combat injuries, yet general surgeons are increasingly unfamiliar with vascular surgery. This study examines the frequency and type of vascular surgical procedures performed during recent US Military operations from 2002 to 2016., Methods: A retrospective analysis of the Department of Defense Trauma Registry was performed for all Role (R)2 and R3 medical treatment facilities (MTFs), from January 2002 to May 2016. A total of 106 International Classification of Diseases-9th Rev.-Clinical Modification (ICD-9-CM) procedure codes were categorized as vascular and were included in the present analysis. Procedure codes were separated by anatomic location and procedure type. Ligation as part of an amputation was excluded. Grafts were further subdivided by type: synthetic, autologous, and unknown. Procedure grouping and categorization were determined by subject matter experts. Data analysis used Stata Version 14 (College Station, TX)., Results: A total of 25,816 vascular surgical procedures were identified at R2 and R3 MTFs. Role 3 MTFs reported more than four times the number of procedures compared to R2 MTFs. The most common anatomic locations documented were extremity (64.96%) and not otherwise specified (28.1%). The most common procedures overall were amputation (33.36%) and fasciotomy (18.83%). The most common graft type was autologous (68.87%), and the least common was synthetic (5.69%)., Conclusion: While amputation, fasciotomy, and ligation were the most common vascular procedures performed for combat trauma, the need for definitive repair including grafting is common at both R2 and R3 MTFs. Vascular surgery therefore remains a necessary skill set for the deployed US Military surgeon; military general surgeons need to train and sustain their vascular skills, including proficiency at amputation and fasciotomy., Level of Evidence: Epidemiologic study, level III.

Background: Abdominal surgery constitutes approximately 13% of surgical procedures performed for combat injuries. This study examines the frequencies and type of abdominal surgical procedures performed during recent US Military operations., Methods: A retrospective analysis of the Department of Defense Trauma Registry was performed for all Role 2 (R2) and Role 3 (R3) medical treatment facilities (MTFs), from January 2002 to May 2016. The 273 International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes that were identified as abdominal surgical procedures were stratified into 24 groups based on anatomic and functional classifications and then grouped by whether they were laparoscopic. Procedure grouping and categorization were determined, and adjudicated if necessary, by subject matter experts. Data analysis used Stata version 14 (College Station, TX)., Results: A total of 26,548 abdominal surgical procedures were identified at R2 and R3 MTFs. The majority of abdominal surgical procedures were reported at R3 facilities. The largest procedure group at both R2 and R3 MTFs were procedures involving the bowel. There were 18 laparoscopic procedures reported (R2: 4 procedures, R3: 14 procedures). Laparotomy not otherwise specified was the second largest procedure group at both R2 (1,060 [24.55%]) and R3 (4,935 [22.2%]) MTFs. Abdominal caseload was variable over the 15-year study period., Conclusions: Surgical skills such as open laparotomy and procedures involving the bowel are crucial in war surgery. The abundance of laparotomy not otherwise specified may reflect inadequate documentation, or the plethora of second- and third-look operations and washouts performed for complex abdominal injuries. Traditional elective general surgical cases (gallbladder, hernia) were relatively infrequent. Laparoscopy was almost nonexistent. Open abdominal surgical skills therefore remain a necessity for the deployed US Military General Surgeons; this is at odds with the shifting paradigm from open to laparoscopic skills in stateside civilian and military hospitals., Level of Evidence: Epidemiologic study, level III.

Level of Evidence: Observational/retrospective/historic controls, level IV.

Background: Reducing time from injury to care can optimize trauma patient outcomes. A previous study of prehospital transport of US military casualties during the Afghanistan conflict demonstrated the importance of time and treatment capability for combat casualty survival., Methods: A retrospective descriptive analysis was conducted to analyze battlefield data collected on US military combat casualties during the Iraq conflict from March 19, 2003, to August 31, 2010. All casualties were analyzed by mortality outcome (killed in action, died of wounds, case fatality rate) and compared with Afghanistan conflict. Detailed data for those who underwent prehospital transport were analyzed for effects of transport time, injury severity, and blood transfusion on survival., Results: For the total population, percent killed in action (16.6% vs. 11.1%), percent died of wounds (5.9% vs. 4.3%), and case fatality rate (10.0 vs. 8.6) were higher for Iraq versus Afghanistan (p < 0.001). Among 1,692 casualties (mean New Injury Severity Score, 22.5; mortality, 17.6%) with detailed data, the injury mechanism included 77.7% from explosions and 22.1% from gunshot wounds. For prehospital transport, 67.6% of casualties were transported within 60 minutes, and 32.4% of casualties were transported in greater than 60 minutes. Although 97.0% of deaths occurred in critical casualties (New Injury Severity Score, 25-75), 52.7% of critical casualties survived. Critical casualties were transported more rapidly (p < 0.01) and more frequently within 60 minutes (p < 0.01) than other casualties. Critical casualties had lower mortality when blood was received (p < 0.01). Among critical casualties, blood transfusion was associated with survival irrespective of transport time within or greater than 60 minutes (p < 0.01)., Conclusion: Although data were limited, early blood transfusion was associated with battlefield survival in Iraq as it was in Afghanistan., Level of Evidence: Performance improvement and epidemiological, level IV.

Background: Most combat casualties who die, do so in the prehospital setting. Efforts directed toward alleviating prehospital combat trauma death, known as killed in action (KIA) mortality, have the greatest opportunity for eliminating preventable death., Methods: Four thousand five hundred forty-two military casualties injured in Afghanistan from September 11, 2001, to March 31, 2014, were included in this retrospective analysis to evaluate proposed explanations for observed KIA reduction after a mandate by Secretary of Defense Robert M. Gates that transport of injured service members occur within 60 minutes. Using inverse probability weighting to account for selection bias, data were analyzed using multivariable logistic regression and simulation analysis to estimate the effects of (1) gradual improvement, (2) damage control resuscitation, (3) harm from inadequate resources, (4) change in wound pattern, and (5) transport time on KIA mortality., Results: The effect of gradual improvement measured as a time trend was not significant (adjusted odds ratio [AOR], 0.99; 95% confidence interval [CI], 0.94-1.03; p = 0.58). For casualties with military Injury Severity Score of 25 or higher, the odds of KIA mortality were 83% lower for casualties who needed and received prehospital blood transfusion (AOR, 0.17; 95% CI, 0.06-0.51; p = 0.002); 33% lower for casualties receiving initial treatment by forward surgical teams (AOR, 0.67; 95% CI, 0.58-0.78; p < 0.001); 70%, 74%, and 87% lower for casualties with dominant injuries to head (AOR, 0.30; 95% CI, 0.23-0.38; p < 0.001), abdomen (AOR, 0.26, 95% CI, 0.19-0.36; p < 0.001) and extremities (AOR, 0.13; 95% CI, 0.09-0.17; p < 0.001); 35% lower for casualties categorized with blunt injuries (AOR, 0.65; 95% CI, 0.46-0.92; p = 0.01); and 39% lower for casualties transported within one hour (AOR, 0.61; 95% CI, 0.51-0.74; p < 0.001). Results of simulations in which transport times had not changed after the mandate indicate that KIA mortality would have been 1.4% higher than observed, equating to 135 more KIA deaths (95% CI, 105-164)., Conclusion: Reduction in KIA mortality is associated with early treatment capabilities, blunt mechanism, select body locations of injury, and rapid transport., Level of Evidence: Therapy, level III.

Background: Tranexamic acid (TXA) has been previously reported to have a mortality benefit in civilian and combat-related trauma, and was thus added to the Joint Theater Trauma System Damage Control Resuscitation Clinical Practice Guideline. As part of ongoing system-wide performance improvement, the use of TXA has been closely monitored. The goal was to evaluate the efficacy and safety of TXA use in military casualties and provide additional guidance for continued use., Methods: A total of 3,773 casualties were included in this retrospective, observational study of data gathered from a trauma registry. The total sample, along with three subsamples for massive transfusion patients (n = 784), propensity-matched sample (n = 1,030), and US/North Atlantic Treaty Organization (NATO) military (n = 1,262), was assessed for administration of TXA and time from injury to administration of TXA. Outcomes included mortality and occurrence of pulmonary embolism and deep vein thrombosis. Multivariable proportional hazards regression models with robust standard error estimates were used to estimate hazard ratios (HR) for assessment of outcomes while controlling for covariates., Results: Results of univariate and multivariate analyses of the total sample (HR, 0.97; 95% confidence interval [CI], 0.62-1.53; p = 0.86), massive transfusion sample (HR, 0.84; 95% CI, 0.46-1.56; p = 0.51), propensity-matched sample (HR, 0.68; 95% CI, 0.27-1.73; p = 0.34), and US/NATO military sample (HR, 0.76; 95% CI, 0.30-1.92; p = 0.48) indicate no statistically significant association between TXA use and mortality. Use of TXA was associated with increased risk of pulmonary embolism in the total sample (HR, 2.82; 95% CI, 2.08-3.81; p < 0.001), massive transfusion sample (HR, 3.64; 95% CI, 1.96-6.78; p = 0.003), US/NATO military sample (HR, 2.55; 95% CI, 1.73-3.69; p = 0.002), but not the propensity-matched sample (HR, 3.36; 95% CI, 0.80-14.10; p = 0.10). TXA was also associated with increased risk of deep vein thrombosis in the total sample (HR, 2.00; 95% CI, 1.21-3.30; p = 0.02) and US/NATO military sample (HR, 2.18; 95% CI, 1.20-3.96; p = 0.02)., Conclusion: In the largest study on TXA use in a combat trauma population, TXA was not significantly associated with mortality, due to lack of statistical power. However, our HR estimates for mortality among patients who received TXA are consistent with previous findings from the CRASH-2 trial. At the same time, continued scrutiny and surveillance of TXA use in military trauma, specifically for prevention of thromboembolic events, is warranted., Level of Evidence: Therapeutic, level IV.

Background: Relatively few publications exist on surgical workload in the deployed military setting. This study analyzes US military combat surgical workload in Iraq and Afghanistan to gain a more thorough understanding of surgical training gaps and personnel requirements., Methods: A retrospective analysis of the Department of Defense Trauma Registry was performed for all Role 2 (R2) and Role 3 (R3) military treatment facilities from January 2001 to May 2016. International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes were grouped into 18 categories based on functional surgical skill sets. The 189,167 surgical procedures identified were stratified by role of care, month, and year. Percentiles were calculated for the number of procedures for each skill set. A literature search was performed for publications documenting combat surgical workload during the same period., Results: A total of 23,548 surgical procedures were performed at R2 facilities, while 165,619 surgical procedures were performed at R3 facilities. The most common surgical procedures performed overall were soft tissue (37.5%), orthopedic (13.84%), abdominal (13.01%), and vascular (6.53%). The least common surgical procedures performed overall were cardiac (0.23%), peripheral nervous system (0.53%), and spine (0.34%).Mean surgical workload at any point in time clearly underrepresented those units in highly kinetic areas, at times by an order of magnitude or more. The published literature always demonstrated workloads well in excess of the 50th percentile for the relevant time period., Conclusions: The published literature on combat surgical workload represents the high end of the spectrum of deployed surgical experience. These trends in surgical workload provide vital information that can be used to determine the manpower needs of future conflicts in ever-changing operational tempo environments. Our findings provide surgical types and surgical workload requirements that will be useful in surgical training and placement of medical assets in future conflicts., Level of Evidence: Epidemiologic study, level III; Care management, level III.

Background: A Role 2 registry (R2R) was developed in 2008 by the US Joint Trauma System (JTS). The purpose of this project was to undertake a preliminary review of the R2R to understand combat trauma epidemiology and related interventions at these facilities to guide training and optimal use of forward surgical capability in the future., Methods: A retrospective review of available JTS R2R records; the registry is a convenience sample entered voluntarily by members of the R2 units. Patients were classified according to basic demographics, affiliation, region where treatment was provided, mechanism of injury, type of injury, time and method of transport from point of injury (POI) to R2 facility, interventions at R2, and survival. Analysis included trauma patients aged ≥18 years or older wounded in year 2008 to 2014, and treated in Afghanistan., Results: A total of 15,404 patients wounded and treated in R2 were included in the R2R from February 2008 to September 2014; 12,849 patients met inclusion criteria. The predominant patient affiliations included US Forces, 4,676 (36.4%); Afghan Forces, 4,549 (35.4%); and Afghan civilians, 2,178 (17.0%). Overall, battle injuries predominated (9,792 [76.2%]). Type of injury included penetrating, 7,665 (59.7%); blunt, 4,026 (31.3%); and other, 633 (4.9%). Primary mechanism of injury included explosion, 5,320 (41.4%); gunshot wounds, 3,082 (24.0%); and crash, 1,209 (9.4%). Of 12,849 patients who arrived at R2, 167 (1.3%) were dead; of 12,682 patients who were alive upon arrival, 342 (2.7%) died at R2., Conclusion: This evaluation of the R2R describes the patient profiles of and common injuries treated in a sample of R2 facilities in Afghanistan. Ongoing and detailed analysis of R2R information may provide evidence-based guidance to military planners and medical leaders to best prepare teams and allocate R2 resources in future operations. Given the limitations of the data set, conclusions must be interpreted in context of other available data and analyses, not in isolation., Level of Evidence: Epidemiologic study, level IV.

Background: The Military Injury Severity Score (mISS) was developed to better predict mortality in complex combat injuries but has yet to be validated., Methods: US combat trauma data from Afghanistan and Iraq from January 1, 2003, to December 31, 2014, from the US Department of Defense Trauma Registry (DoDTR) were analyzed. Military ISS, a variation of the ISS, was calculated and compared with standard ISS scores.Receiver operating characteristic curve, area under the curve, and Hosmer-Lemeshow statistics were used to discriminate and calibrate between mISS and ISS. Wilcoxon-Mann-Whitney, t test and χ tests were used, and sensitivity and specificity calculated. Logistic regression was used to calculate the likelihood of mortality associated with levels of mISS and ISS overall., Results: Thirty thousand three hundred sixty-four patients were analyzed. Most were male (96.8%). Median age was 24 years (interquartile range [IQR], 21-29 years). Battle injuries comprised 65.3%. Penetrating (39.5%) and blunt (54.2%) injury types and explosion (51%) and gunshot wound (15%) mechanisms predominated. Overall mortality was 6.0%.Median mISS and ISS were similar in survivors (5 [IQR, 2-10] vs. 5 [IQR, 2-10]) but different in nonsurvivors, 30 (IQR, 16-75) versus 24 (IQR, 9-23), respectively (p < 0.0001). Military ISS and ISS were discordant in 17.6% (n = 5,352), accounting for 56.2% (n = 1,016) of deaths. Among cases with discordant severity scores, the median difference between mISS and ISS was 9 (IQR, 7-16); range, 1 to 59. Military ISS and ISS shared 78% variability (R = 0.78).Area under the curve was higher in mISS than in ISS overall (0.82 vs. 0.79), for battle injury (0.79 vs. 0.76), non-battle injury (0.87 vs. 0.86), penetrating (0.81 vs. 0.77), blunt (0.77 vs. 0.75), explosion (0.81 vs. 0.78), and gunshot (0.79 vs. 0.73), all p < 0.0001. Higher mISS and ISS were associated with higher mortality. Compared with ISS, mISS had higher sensitivity (81.2 vs. 63.9) and slightly lower specificity (80.2 vs. 85.7)., Conclusion: Military ISS predicts combat mortality better than does ISS., Level of Evidence: Prognostic and epidemiologic study, level III.