Future directions in brain injury research.

This paper reviews the potential future directions that are important for brain injury research, especially with regard to concussion. The avenues of proposed research are categorized according to current concepts of concussion, types of concussion, and a global schema for globally reducing the burden of concussion.

Combat injury coding: a review and reconfiguration.

Background: The current civilian Abbreviated Injury Scale (AIS), designed for automobile crash injuries, yields important information about civilian injuries. It has been recognized for some time, however, that both the AIS and AIS-based scores such as the Injury Severity Score (ISS) are inadequate for describing penetrating injuries, especially those sustained in combat. Existing injury coding systems do not adequately describe (they actually exclude) combat injuries such as the devastating multi-mechanistic injuries resulting from attacks with improvised explosive devices (IEDs).

Neuropathological findings in disabled survivors of a head injury.

We investigated how the occurrence and severity of the main neuropathological types of traumatic brain injury (TBI) influenced the severity of disability after a head injury. Eighty-five victims, each of whom had lived at least a month after a head injury but then died, were studied. Judged by the Glasgow Outcome Scale (GOS), before death 35 were vegetative, 30 were severely and 20 were moderately disabled.

Severe-to-fatal head injuries in motor vehicle impacts.

Severe-to-fatal head injuries in motor vehicle environments were analyzed using the United States Crash Injury Research and Engineering Network database for the years 1997-2006. Medical evaluations included details and photographs of injury, and on-scene, trauma bay, emergency room, intensive care unit, radiological, operating room, in-patient, and rehabilitation records. Data were synthesized on a case-by-case basis.

Experimental study of blast-induced traumatic brain injury using a physical head model.

This study was conducted to quantify intracranial biomechanical responses and external blast overpressures using physical head model to understand the biomechanics of blast traumatic brain injury and to provide experimental data for computer simulation of blast-induced brain trauma. Ellipsoidal-shaped physical head models, made from 3-mm polycarbonate shell filled with Sylgard 527 silicon gel, were used. Six blast tests were conducted in frontal, side, and 45 degrees oblique orientations.

Withdrawal of life support in critically ill neurosurgical patients and in-hospital death after discharge from the neurosurgical intensive care unit. Clinical article.

Object: The aim of this study was to examine the variables influencing the mode and location of death in patients admitted to a neurosurgical intensive care unit (NICU), including the participation of a newly appointed neurointensivist (NI).

Methods: Data from all patients admitted to a university hospital NICU were prospectively collected and compared between 2 consecutive 19-month periods before and after the appointment of an NI.

Results: One thousand eighty-seven patients were admitted before and 1279 after the NI's appointment.

A finite element study of blast traumatic brain injury - biomed 2009.

An idealized finite element human head model was constructed to study biomechanical responses in the brain due to blast overpressure loading from a blast of 10 kg TNT at 1 meter. Brain strain in the coup and contrecoup regions were 4-7x higher than the central region, and high brain strain (15%) large deformation (4 mm) occurred in the brainstem region, indicating a higher probability of injury in the peripheral brain and brainstem regions due to blast overpressure loading.

Traumatic brain injury after frontal crashes: relationship with body mass index.

Background: Previous studies had demonstrated that injury severity and risk of death after motor-vehicle crashes are related to human body characteristics. The purpose of this study was to clarify the relationship between body mass index (BMI) and head injury severity in front seat passengers after a frontal collision.

Methods: Data from all front seat occupants with at least one injury, older than 16 years old involved in a frontal collision from 1993 to 2005 were retrieved from the National Automotive Sampling System (NASS) database.

Association of contact loading in diffuse axonal injuries from motor vehicle crashes.

Background: Although studies have been conducted to analyze brain injuries from motor vehicle crashes, the association of head contact has not been fully established. This study examined the association in occupants sustaining diffuse axonal injuries (DAIs).

Methods: The 1997 to 2006 motor vehicle Crash Injury Research Engineering Network database was used.

How to test brain and brain simulant at ballistic and blast strain rates.

Mechanical properties of brain tissue and brain simulant at strain rate in the range of 1000 s-1 are essential for computational simulation of intracranial responses for ballistic and blast traumatic brain injury. Testing these ultra-soft materials at high strain rates is a challenge to most conventional material testing methods. The current study developed a modified split Hopkinson bar techniques using the combination of a few improvements to conventional split Hopkinson bar including: using low impedance aluminum bar, semiconductor strain gauge, pulse shaping technique and annular specimen.

Influence of angular acceleration-deceleration pulse shapes on regional brain strains.

Recognizing the association of angular loading with brain injuries and inconsistency in previous studies in the application of the biphasic loads to animal, physical, and experimental models, the present study examined the role of the acceleration-deceleration pulse shapes on region-specific strains. An experimentally validated two-dimensional finite element model representing the adult male human head was used. The model simulated the skull and falx as a linear elastic material, cerebrospinal fluid as a hydrodynamic material, and cerebrum as a linear viscoelastic material.

In vitro and in vivo characterization of neurally modified mesenchymal stem cells induced by epigenetic modifiers and neural stem cell environment.

Mesenchymal stem cell (MSC)-mediated tissue regeneration is a promising strategy to treat several neurodegenerative diseases and traumatic injuries of the central nervous system. Bone marrow MSCs have great potential as therapeutic agents, since they are easy to isolate and expand and are capable of producing various cell types, including neural cells. Recently we developed a highly efficient methodology to produce neural stem-like and neural precursor-like cells from mice bone marrow-derived MSCs that eventually differentiate into neuronal- and glial-like cells in vitro.

Chest deflections and injuries in oblique lateral impacts.

A majority of laboratory-driven side-impact injury assessments are conducted using postmortem human subjects (PMHS) under the pure lateral mode. Because real-world injuries occur under pure and oblique modes, this study was designed to determine chest deflections and injuries using PMHS under the latter mode. Anthropometrical data were obtained and x-rays were taken.

New rat model for diffuse brain injury using coronal plane angular acceleration.

A new experimental model was developed to induce diffuse brain injury (DBI) in rats through pure coronal plane angular acceleration. An impactor was propelled down a guide tube toward the lateral extension of the helmet fixture. Upon impactor-helmet contact, helmet and head were constrained to rotate in the coronal plane.

High-speed 3-D kinematics from whole-body lateral impact sled tests.

While lateral impact sled studies have been conducted to determine injuries, injury mechanisms, and derive human tolerance using post mortem human subject (PMHS) for the chest and pelvis regions of the human body, there is a paucity of three-dimensional (3-D) motions at high-speeds. Since out-of-position occupants respond with 3-D motions even under pure frontal and lateral impacts, it is important to determine such kinematics at high-speeds in the temporal domain. Consequently, the objective of the study was to determine lateral impact-induced 3-D temporal motions at 1,000 frames per sec.

Regional brain strains and role of falx in lateral impact-induced head rotational acceleration.

The objective of the present investigation is to determine localized brains strains in lateral impact using finite element modeling and evaluate the role of the falx. A two-dimensional finite element model was developed and validated with experimental data from literature. Motions and strains from the stress analysis matched well with experimental results.

Biomechanical correlates of mild diffuse brain injury in the rat.

The relationship between diffuse brain injury (DBI) occurrence and impact biomechanics is well documented. Previous studies attempted to develop injury thresholds based on various biomechanical parameters and have demonstrated inconsistent results. The spectral nature of DBI requires robust metrics capable of predicting injury occurrence and severity.

Mechanics of fresh, refrigerated, and frozen arterial tissue.

Arterial grafts and experimental soft tissues are commonly preserved using refrigeration and freezing. The present study was designed to investigate effects of common storage protocols on arterial mechanics. Porcine aortas were axially distracted to failure implementing fresh, refrigerated, and frozen storage conditions.

Experimental model for civilian ballistic brain injury biomechanics quantification.

Biomechanical quantification of projectile penetration using experimental head models can enhance the understanding of civilian ballistic brain injury and advance treatment. Two of the most commonly used handgun projectiles (25-cal, 275 m/s and 9 mm, 395 m/s) were discharged to spherical head models with gelatin and Sylgard simulants. Four ballistic pressure transducers recorded temporal pressure distributions at 308kHz, and temporal cavity dynamics were captured at 20,000 frames/second (fps) using high-speed digital video images.

Biomechanical characterization of internal layer subfailure in blunt arterial injury.

Blunt carotid artery injuries occur in 0.3% of blunt injured patients and may lead to devastating neurological consequences. However, arterial mechanics leading to internal layer subfailure have not been quantified.

AIS 2005: a contemporary injury scale.

To determine and to quantify outcome from injury demands that multiple factors be universally applied so that there is uniform understanding that the same outcome is understood for the same injury. It is thus important to define the variables used in any outcome assessment. Critical to defining outcomes is the need for a universal language that defines individual injuries.

Brain strains in vehicle impact tests.

The purpose of this research was to use vehicle impact test data and parametric finite element analysis to study the contribution of translational accelerations (TransAcc) and rotational accelerations (RotAcc) on strain-induced head injuries. Acceleration data were extracted from 33 non-contact vehicle crash tests conducted by the US Department of Transportation, National Highway Traffic Safety Administration. A human finite element head model was exercised using head accelerations from the nine accelerometer package placed inside the driver dummy in these tests.

Lateral impact injuries with side airbag deployments--a descriptive study.

The present study was designed to provide descriptive data on side impact injuries in vehicles equipped with side airbags using the United States National Automotive Sampling System (NASS). The database was queried with the constraint that all vehicles must adhere to the Federal Motor Vehicle Safety Standards FMVSS 214, injured occupants be in the front outboard seats with no rollovers or ejections, and side impacts airbags be deployed in lateral crashes. Out of the 7812 crashes in the 1997-2004 weighted NASS files, AIS > or = 2 level injuries occurred to 5071 occupants.

Role of translational and rotational accelerations on brain strain in lateral head impact.

Translational and rotational accelerations from blunt head impact can induce excessive brain strain and cause traumatic brain injuries. However, it is not clear which acceleration plays a major role in the mechanism. The current study used the SIMon human finite element head model (FEHM) and delineated the contributions of these accelerations using post mortem human subject (PMHS) lateral head impact experimental data.