Epidemiology of psychiatric disorders sustained by a U.S. Army brigade combat team during the Iraq War

The article of record as published may be found at http://dx.doi.org/10.1016/j.genhosppsych.2010.10.007This study was designed to describe the epidemiology of psychiatric illnesses experienced by soldiers in a combat environment, which has been previously underreported.Approved for public release; distribution is unlimited

Non-emergent orthopaedic injuries sustained by soldiers in Operation Iraqi Freedom

The article of record as published may be found at http://dx.doi.org/10.2106/JBJS.K.00129The majority of soldiers deployed to the theater of combat operations return safely after completion of the deployment. Many of these soldiers sustain non-emergent musculoskeletal injuries that initially are treated nonoperatively and ultimately require surgery following their combat tour.Approved for public release; distribution is unlimited

The Influence of Musculoskeletal Conditions, Behavioral Health Diagnoses, and Demographic Factors on Injury-Related Outcome in a High-Demand Population

The article of record as published may be found at http://dx.doi.org/10.2106/JBJS.M.01050Background: The extent to which musculoskeletal injuries and sociodemographic factors impact long-term out- come remains unknown. The purpose of this study was to provide a prognostic analysis of the influence of muscu- loskeletal conditions, behavioral health diagnoses, and patient-based characteristics on outcomes among a longitudinal cohort. Methods: This is a longitudinal observational study of the population of an Army brigade deployed to Iraq from 2006 to 2007. The 4087 soldiers who survived the deployment were followed for forty-eight months and were observed for the development of chronic musculoskeletal conditions, behavioral health disorders, and inability to remain in active service as indicated by the findings of the Physical Evaluation Board. The influence of demographic factors, behavioral health conditions, and deployment-related musculoskeletal injuries on the capacity to remain in the military was assessed using Poisson multivariate analysis and receiver operating characteristic curves. Results: The mean age of the cohort was twenty-seven years (range, eighteen to fifty-two years). One hundred and sixty- three soldiers sustained combat-related musculoskeletal trauma, and 587 soldiers had musculoskeletal injuries not related to battle. Three hundred and seventy-four soldiers (9%) were found to be unfit by the Physical Evaluation Board, with 236 soldiers (63%) referred for at least one musculoskeletal condition. Of these 236 soldiers, 116 (49%) also had a behavioral health diagnosis. Multivariate regression analysis revealed that junior enlisted rank (incidence rate ratio, 9.7 [95% confidence interval, 3.1 to 30.3]), senior enlisted rank (incidence rate ratio, 5.6 [95% confidence interval, 1.8 to 17.7]), behavioral health diagnosis (incidence rate ratio, 7.4 [95% confidence interval, 5.6 to 9.6]), age of eighteen to twenty-three years (incidence rate ratio, 1.6 [95% confidence interval, 1.2 to 2.3]), and male sex (incidence rate ratio, 2.5 [95% confidence interval, 1.2 to 5.0]) were significant predictors of referral to the Physical Evaluation Board for a musculoskeletal condition. A prognostic model developed using receiver operating characteristic curves and the risk factors of musculoskeletal injury, presence of a psychiatric condition, and lower rank explained 78% (95% confidence interval, 77% to 80%) of the risk of being found unfit by the Physical Evaluation Board. Conclusions: Musculoskeletal conditions, psychological diagnoses, and lower rank (socioeconomic status) were identified as potent predictors of inferior outcome in this study. Targeting at-risk patients within populations may improve results. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence

Combat musculoskeletal wounds in a US Army brigade combat team during Operation Iraqi Freedom

The article of record as published may be found at http://dx.doi.org/10.1097/TA.0b013e3181edebedBackground: A prospective, longitudinal analysis of musculoskeletal combat injuries sustained by a large combat-deployed maneuver unit has not previously been performed. Methods: A detailed description of the musculoskeletal combat casualty care statistics, distribution of wounds, and mechanisms of injury incurred by a US Army Brigade Combat Team during “The Surge” phase of Operation Iraqi Freedom was performed using a centralized casualty database and an electronic medical record system. Results: Among the 4,122 soldiers deployed, there were 242 musculoskeletal combat wounds in 176 combat casualties. The musculoskeletal combat casualty rate for the Brigade Combat Team was 34.2 per 1,000 soldier combat-years. Spine, pelvis, and long bone fractures comprised 55.9% (33 of 59) of the total fractures sustained in combat. Explosions accounted for 80.7% (142 of 176) of all musculoskeletal combat casualties. Musculoskeletal combat casualty wound incidence rates per 1,000 combat-years were as follows: major amputation, 2.1; minor amputation, 0.6; open fracture, 5.0; closed fracture, 6.4; and soft-tissue/neurovascular injury, 32.8. Among musculoskeletal combat casualties, the likelihood of a gunshot wound causing an open fracture was significantly greater (45.8% [11 of 24]) when compared with explosions (10.6% [15 of 142]) (p 0.0006). Long bone amputations were more often caused by explosive mechanisms than gunshot wounds. Conclusions: A large burden of complex orthopedic injuries has resulted from the combat experience in Operation Iraqi Freedom. This is because of increased enemy reliance on explosive devices, the use of individual and vehicular body armor, and improved survivability of combat-injured soldiers

An approach to enhance efficiency of dem modelling of soils with crushable grains

In this study oedometric compression tests of hydrocarbon coke, Fontainebleau sand and silica sand are simulated in three dimensions using breakable particles. The method adapts a rigorous breakage criterion for elasto-brittle spheres to represent failure of grains isolated between platens or within granular masses. The breakage criterion allows for the effect of particle bulk and contact properties to be treated separately. A discrete fragmentation multigenerational approach is applied as a spawning procedure. The number of particles quickly increases during the simulation, but is kept manageable by systematic fine exclusion and upscaling. Fine exclusion leads to mass losses between generations, but that loss is accounted for outside the mechanical model. Sensitivity analysis shows that it is enough to keep 53% of the crushed particle mass within the mechanical model to correctly reproduce experimental macroscopic behaviour. Practical upscaling rules are proposed for (a) contact stiffness, (b) breakage criteria and (c) grain size distribution, and validated simulating the same test, reducing by half the initial number of particles. The results are promising as both the mechanical and grading evolution are well captured with two orders of magnitude savings in computing efficiency.Peer ReviewedPostprint (published version