Mortality Following Hospital Admission for US Active Duty Service Members Diagnosed With Penetrating Traumatic Brain Injury, 2004–2014

Investigation of dynamic responses of skin simulant against fragment impact through experiments and concurrent computational modeling

Perforation of the skin by fragment impact is a key determinant of the severity of an injury and incapacitation during modern asymmetric warfare. Computational models validated against experimental data are thus desired for simulating the responses of a skin simulant against fragment impact. Toward this end, experiments and concurrent computational modeling were used to investigate the dynamic responses of the skin simulant against fragment impact. Fragment simulating projectiles (FSPs) of masses 1.10 g and 2.79 g were considered herein, and the responses of the skin simulant were investigated in terms of the threshold velocity, energy density, peak displacement, and failure mechanisms. The results illustrate numerous salient aspects. The skin simulant failure involved cavity shearing followed by elastic hole enlargement, and these results were sensitive to the strain rate. The best agreement between the simulated and experimental results was achieved when the input stress-strain curves to the simulation were based on the full spectrum of strain rates. When a single stress-strain curve corresponding to a specific strain rate was used as the input, the threshold velocity and peak displacement of the skin simulant were either underpredicted or overpredicted depending on the strain rate considered. The threshold velocity was also sensitive to the input failure strain; here, the best agreement was obtained when the failure strain was based on the theoretical limiting strain. When the FSP materials were changed to plastics, the threshold velocities increased by up to 33%; however, the energy densities and generated stresses exceeded the contusion and laceration thresholds of the skin.

Injury-Transplantation Interval-Dependent Amelioration of Axonal Degeneration and Motor Deficit in Rats with Penetrating Traumatic Brain Injury

Penetrating traumatic brain injury (pTBI) is increasingly survivable, but permanently disabling as adult mammalian nervous system does not regenerate. Recently, our group demonstrated transplant location-dependent neuroprotection and safety of clinical trial-grade human neural stem cell (hNSC) transplantation in a rodent model of acute pTBI. To evaluate whether longer injury-transplantation intervals marked by chronic inflammation impede engraftment, 60 male Sprague-Dawley rats were randomized to three sets. Each set was divided equally into two groups: 1) with no injury (sham) or 2) pTBI. After either 1 week (groups 1 and 2), 2 weeks (groups 3 and 4), or 4 weeks after injury (groups 5 and 6), each animal received 0.5 million hNSCs perilesionally. A seventh group of pTBI animals treated with vehicle served as the negative control. All animals were allowed to survive 12 weeks with standard chemical immunosuppression. Motor capacity was assessed pre-transplant to establish injury-induced deficit and followed by testing at 8 and 12 weeks after transplantation. Animals were euthanized, perfused, and examined for lesion size, axonal degeneration, and engraftment. Compared to vehicle, transplanted groups showed a trend for reduced lesion size and axonal injury across intervals. Remote secondary axonal injury was significantly reduced in groups 2 and 4, but not in group 6. The majority of animals showed robust engraftment independent of the injury-transplant time interval. Modest amelioration of motor deficit paralleled the axonal injury trend. In aggregate, pTBI-induced remote secondary axonal injury was resolved by early, but not delayed, hNSC transplantation.

Penetrating injuries in Germany - epidemiology, management and outcome an analysis based on the TraumaRegister DGU®

Background

The management of penetrating wounds is a rare challenge for trauma surgeons in Germany and Central Europe as a result of the low incidence of this type of trauma. In Germany, penetrating injuries are reported to occur in 4–5 % of the severely injured patients who are enrolled in the TraumaRegister DGU® (trauma registry of the German Trauma Society). They include gunshot injuries, knife stab injuries, which are far more common, and penetrating injuries of other origin, for example trauma caused by accidents. The objective of this study was to assess the epidemiology and outcome of penetrating injuries in Germany, with a particular focus on the level of care provided by the treating trauma centre to gain more understanding of this trauma mechanism and to anticipate the necessary steps in the initial treatment.

Materials and methods

Since 2009, the TraumaRegister DGU® has been used to assess not only whether a trauma was penetrating but also whether it was caused by gunshot or stabbing. Data were taken from the standard documentation forms that participating German hospitals completed between 2009 and 2018. Excluded were patients with a maximum abbreviated injury scale (MAIS) score of 1 with a view to obtaining a realistic idea of this injury entity, which is rare in Germany.

Results

From 2009 to 2018, there were 1123 patients with gunshot wounds, corresponding to a prevalence rate of 0.5 %, and 4333 patients with stab wounds (1.8 %), which were frequently caused by violent crime. The high proportion of intentionally self-inflicted gunshot wounds to the head resulted in a cumulative mortality rate of 41 % for gunshot injuries. Stab wounds were associated with a lower mortality rate (6.8 %). Every fourth to fifth patient with a gunshot or stab wound presented with haemorrhagic shock, which is a problem that is seen during both the prehospital and the inhospital phase of patient management. Of the patients with penetrating injuries, 18.3 % required transfusions. This percentage was more than two times higher than that of the basic group of patients of the TraumaRegister DGU®, which consists of patients with a MAIS ≥ 3 and patients with a MAIS of 2 who died or were treated on the intensive care unit.

Conclusions

In Germany, gunshot and stab wounds have a low incidence and are mostly caused by violent crime or attempted suicides. Depending on the site of injury, they have a high mortality and are often associated with major haemorrhage. As a result of the low incidence of these types of trauma, further data and analyses are required in order to provide the basis for evaluating the long-term quality of the management of patients with stab or gunshot wounds.

Estimates of Long-Term Disability Among US Service Members With Traumatic Brain Injuries

BACKGROUND

Traumatic brain injury (TBI) is a significant health issue in the US military. The purpose of this study was to estimate the probability of long-term disability among hospitalized service members (SMs) with TBIs, using the South Carolina Traumatic Brain Injury and Follow-up Registry (SCTBIFR) model developed on civilian hospitalized patients.

METHODS

We identified military patients in military or civilian hospitals or theater level 3 to 5 military treatment facilities (MTFs) whose first TBI occurred between October 1, 2013, and September 30, 2015. TBI-related disability at 1-year post-hospital discharge was estimated using regression coefficients from the SCTBIFR.

RESULTS

Among the identified 4877 SMs, an estimated 65.6% of SMs with severe TBI, 56.2% with penetrating TBI, 31.4% with moderate TBI, and 12.0% with mild TBI are predicted to develop long-term disability. TBI patients identified at theater level 4 and 5 MTFs had an average long-term disability rate of 56.9% and 61.1%, respectively. In total, we estimate that 25.2% of all SMs hospitalized with TBI will develop long-term disability.

CONCLUSION

Applying SCTBIFR long-term probability estimates to US SMs with TBIs provides useful disability estimates to inform providers and health systems on the likelihood that particular subgroups of TBI patients will require continued support and long-term care.

Human neural stem cell transplant location-dependent neuroprotection and motor deficit amelioration in rats with penetrating traumatic brain injury

BACKGROUND

Penetrating traumatic brain injury induces chronic inflammation that drives persistent tissue loss long after injury. Absence of endogenous reparative neurogenesis and effective neuroprotective therapies render injury-induced disability an unmet need. Cell replacement via neural stem cell transplantation could potentially rebuild the tissue and alleviate penetrating traumatic brain injury disability. The optimal transplant location remains to be determined.

METHODS

To test if subacute human neural stem cell (hNSC) transplant location influences engraftment, lesion expansion, and motor deficits, rats (n = 10/group) were randomized to the following four groups (uninjured and three injured): group 1 (Gr1), uninjured with cell transplants (sham+hNSCs), 1-week postunilateral penetrating traumatic brain injury, after establishing motor deficit; group 2 (Gr2), treated with vehicle (media, no cells); group 3 (Gr3), hNSCs transplanted into lesion core (intra); and group 4 (Gr4), hNSCs transplanted into tissue surrounding the lesion (peri). All animals were immunosuppressed for 12 weeks and euthanized following motor assessment.

RESULTS

In Gr2, penetrating traumatic brain injury effect manifests as porencephalic cyst, 22.53 ± 2.87 (% of intact hemisphere), with p value of <0.0001 compared with uninjured Gr1. Group 3 lesion volume at 17.44 ± 2.11 did not differ significantly from Gr2 (p = 0.36), while Gr4 value, 9.17 ± 1.53, differed significantly (p = 0.0001). Engraftment and neuronal differentiation were significantly lower in the uninjured Gr1 (p < 0.05), compared with injured groups. However, there were no differences between Gr3 and Gr4. Significant increase in cortical tissue sparing (p = 0.03), including motor cortex (p = 0.005) was observed in Gr4 but not Gr3. Presence of transplant within lesion or in penumbra attenuated motor deficit development (p < 0.05) compared with Gr2.

CONCLUSION

In aggregate, injury milieu supports transplanted cell proliferation and differentiation independent of location. Unexpectedly, cortical sparing is transplant location dependent. Thus, apart from cell replacement and transplant mediated deficit amelioration, transplant location-dependent neuroprotection may be key to delaying onset or preventing development of injury-induced disability.

LEVEL OF EVIDENCE

Preclinical study evaluation of therapeutic intervention, level VI.

Gender Differences in Outcomes after Traumatic Brain Injury among Service Members and Veterans

This scoping study describes the range of outcomes in traumatic brain injury (TBI) studies of military service members and veterans addressing gender differences. A secondary purpose is to identify differences in outcomes between male and female participants in such studies. We searched PubMed, CiNAHL, and PsycInfo databases for relevant articles. Two reviewers independently screened results. Of 822 unique titles and abstracts screened for eligibility, 55 full articles were reviewed, with 29 studies meeting full inclusion criteria. Twenty of the 29 included studies used retrospective designs and all but two used data collected from Veterans Affairs or Department of Defense health care settings. TBI was diagnosed by self-report, screening, and evaluation procedures, and medical record documentation. Ten different outcome categories were identified among the included studies. In general, female service members and veterans have not been well represented in TBI outcomes research. Evidence suggests that female veterans with mild TBI (mTBI) report more neurobehavioral symptoms and use more outpatient services than male veterans. Studies also indicate that female veterans with TBI are more frequently diagnosed with depression. Additional research is essential to support precision treatment recommendations for female veterans with TBI, as women represent a growing proportion of the patients served by the Veterans Health Administration. LEVEL OF EVIDENCE: IV.

Role of Toll-like receptor mediated signaling in traumatic brain injury

The mechanisms underlying secondary brain damage following traumatic brain injury (TBI) remain unclear. A great many studies have demonstrated that inflammatory cascades contribute to brain damage through the activation of immune/inflammatory responses, including the increased release of cytokines and chemokines, and the recruitment of leukocytes. The cells and tissues damaged by primary mechanical injury release a number of endogenous factors acting as damage-associated molecular patterns (DAMPs), which initiate and perpetuate noninfectious inflammatory responses through transduction signaling pathways. Toll-like receptors (TLRs) are a transmembrane receptor family that can recognize the specific DAMPs released from damaged cells and recruit a set of adaptors leading to the activation of downstream kinases and nuclear factors which regulate the expression of inflammatory genes. The activation of inflammatory responses mediated by TLR signaling is closely associated with brain tissue damage and neurological dysfunction following TBI. TLRs and their downstream protein kinases may be potential targets for the treatment of TBI. Modulation of TLR-mediated signaling may attenuate brain damage and improve TBI outcome. In this review, we briefly discuss the role of TLR-mediated signaling in TBI and the new treatments targeting TLR signaling. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".