Neurobehavioural outcomes of penetrating and tangential gunshot wounds to the head

The Medical Costs of Firearm Injuries in the United States: A Systematic Review

BACKGROUND

Firearm injury poses a significant public health burden in the United States.

OBJECTIVES

The purpose of this systematic review was to provide a comprehensive accounting of the medical costs of firearm injuries in the United States.

METHODS

A systematic literature review was conducted to identify studies published between January 1, 2000 and July 13, 2022 that reported medical costs of firearm injuries. A search of Embase, PubMed, and the Cochrane Library databases was performed by a medical librarian. The National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was used to evaluate for risk of bias. Health care-related charges and costs per firearm injury were presented and trends were identified.

RESULTS

Sixty-four studies were included in the analysis. Study sample sizes ranged from 18 to 868,483 patients. Reported costs per injury ranged from $261 to $529,609. The median cost reported was $27,820 (interquartile range [IQR] $15,133-$40,124) and median charge reported was $53,832 (IQR $38,890-$98,632). Studies that divided initial hospitalization costs and follow-up medical costs identified that initial hospitalization accounts for about 60% of total costs.

CONCLUSIONS

We found a significant volume of literature about the medical costs of firearm injury, which identified a highly heterogeneous cost burden. A significant amount of cost burden occurs after the index hospitalization, which is the only cost reported in most studies. Limitations of this study include reporting bias that favors hospitalized patients as well as a large focus on hospital charges as measurements of cost identified in the literature.

Age-related trends in intracranial injury outcomes

BACKGROUND

Age is an important prognostic indicator of outcomes following traumatic brain injuries. This study examines how outcomes for traumatic brain injuries in the acute care setting have changed during a recent 10-year period.

METHODS

Population-level data broken down by age group was obtained from the Agency for Healthcare Research and Quality Web site for the years 2000 to 2009. Linear regression was used to determine trends in age-specific discharge volume, mortality rate, discharge disposition, and cost. Population and cost estimates were adjusted using census data and consumer price index.

RESULTS

It was found that discharges for intracranial injuries have been increasing, with the most marked increase in the population older than 65 years, which cannot be accounted for by population age distribution changes. There were overall improvements in outcomes including decreased in-hospital mortality rates for all age groups and increased home discharges for those 18 to 44 years and older than 85 years. This came at an average annual cost increase of $1,071 dollars per patient.

CONCLUSION

Acute care outcomes for intracranial injuries have been improving at a cost of $1,071 per patient per year.

LEVEL OF EVIDENCE

Economic and decision analysis, level IV.

A tangential gunshot wound to the head: case report and review of the literature

BACKGROUND

Patients with tangential gunshot wounds (TGSWs) commonly present with a good Glasgow Coma Scale score and without a history of loss of consciousness. Typically, the bullet does not breach the skull, however, there is a considerable force directed into the brain, and these patients are best treated as sustaining a moderate-to-severe blunt head injury. These patients require observation and repeat imaging. Physicians should be aware of this entity as these patients can deteriorate in a delayed fashion.

OBJECTIVES

The authors present a case of a TGSW to the head in a neurologically intact patient. The initial post-injury computed tomography (CT) scan showed a very small subdural hematoma (SDH) with no overlying fracture of the skull. A delayed CT scan performed 4 h after arrival to the Emergency Department and 6 h after injury demonstrated an increase in size of the SDH, new traumatic subarachnoid hemorrhage, and bilateral cerebral contusions. Clinically, the patient showed worsening of her neurological examination. She underwent aggressive non-surgical treatment for increased intracranial pressure with almost complete recovery.

CONCLUSION

Although patients with TGSWs are typically in good condition upon presentation, these injuries are not always trivial, and these patients should have, at minimum, a non-contrast brain CT scan to evaluate underlying damage to the brain and skull. In addition, a delayed CT scan and close observation on a neurosurgical service are indicated.

Penetrating ballistic-like brain injury in the rat: differential time courses of hemorrhage, cell death, inflammation, and remote degeneration

Acute and delayed cerebral injury was assessed in a recently developed rat model of a penetrating ballistic-like brain injury (PBBI). A unilateral right frontal PBBI trajectory was used to induce survivable injuries to the frontal cortex and striatum. Three distinct phases of injury progression were observed. Phase I (primary injury, 0-6 h) began with immediate (<5 min) intracerebral hemorrhage (ICH) that reached maximal volumetric size at 6 h (27.0 +/- 2.9 mm(3)). During Phase II (secondary injury, 6-72 h), a core lesion of degenerate neurons surrounding the injury track expanded into peri-lesional areas to reach a maximal volume of 69.9 +/- 6.1 mm(3) at 24 h. The core lesion consisted of predominately necrotic cell death and included marked infiltration of both neutrophils (24 h) and macrophages (72 h). Phase III (delayed degeneration, 3-7 days) involved the degeneration of neurons and fiber tracts remote from the core lesion including the thalamus, internal capsule, external capsule, and cerebral peduncle. Overall, different time courses of hemorrhage, lesion evolution, and inflammation were consistent with complementary roles in injury development and repair, providing key information about these mediators of primary, secondary, and delayed brain injury development. The similarities/differences of PBBI to other focal brain injury models are discussed.

Severity level and injury track determine outcome following a penetrating ballistic-like brain injury in the rat

Penetrating ballistic brain injury (PBBI) is a high-energy transfer wound causing direct damage to the cerebrum. Outcome is directly related to the ballistic's anatomical path and degree of energy transfer. In this study we evaluated differences in outcome induced by altering the 'projectile' paths and severity levels of a simulated bullet wound using a newly characterized rat model of PBBI. Severity levels (5, 10, and 15%) were compared across three distinct injury paths: (1) unilateral 'frontal', (2) 'bilateral' hemispheric, and (3) unilateral 'caudal' (including cerebellum/midbrain). Outcome was assessed by differences in mortality rate and motor dysfunction (e.g. neurological and balance beam deficits). Results indicated that outcome was dependent not only on the severity level of PBBI (P<0.001, r=0.535) but also brain regions injured (P<0.001, r=0.398). A unilateral caudal injury was associated with the highest degree of mortality (up to 100%) and motor dysfunction (64-100% disability). Bilateral hemispheric injuries were also potentially fatal, while the best outcomes were associated with a unilateral frontal injury (no mortality and 14-39% motor disability). These data closely resemble clinical reports of ballistic wounds to the head and further validate the rat PBBI model with the ultimate intent to investigate novel therapeutic approaches for diagnosis and treatment of the neuropathological damage associated with PBBI.

Characterization of a New Rat Model of Penetrating Ballistic Brain Injury

Penetrating brain injury (PBI) is a leading cause of mortality and morbidity in modern warfare and accounts for a significant number of traumatic brain injuries worldwide. Here we characterize the pathophysiology of a new rat model of PBI that simulates the large temporary cavity caused by energy dissipation from a penetrating bullet round. Male Sprague-Dawley rats (250-300 g) were subjected to a simulated ballistic wound to the right frontal hemisphere implemented by an inflatable penetrating probe. Three levels of injury severity were compared to control animals. Neurological and physiological outcome was assessed over a 3-day recovery period and brain tissue collected at 72 h for histopathological evaluation. Brain-injured regions included the ipsilateral frontal cortex and striatum with volumetric increases in intracranial hemorrhage (5-18 mm3) and lesion size (9-86 mm3) related to severity. Similarly, hemispheric swelling increased (3-14%) following PBI, associated with a significant rise in intracranial pressure. Astrogliosis was present in regions adjacent to the core-injury along with microglial and leukocyte infiltration. Injury remote to the lesion was observed in the cerebral peduncle that may have accounted, in part, for observed neurological deficits. Neurological and balance beam testing revealed sensorimotor deficits that persisted through 72 h. Severe electroencephalographic disturbances included the occurrence of cortical spreading depression, slow-waves, and brain seizure activity. In conclusion, this rat PBI model replicates diverse, salient features of clinical PBI pathology, generates reproducible and quantifiable measures of outcome, and is scalable by injury severity, rendering it an attractive vehicle for experimental brain trauma research.