Delayed-Onset Neuropathological Complications From a Foramen Magnum and Occipital Crest-Focused Traumatic Brain Injury of the Vietnam War and Other Conflicts: Part II, Research Analysis.

INTRODUCTION: Much of the research impacting diagnosis, outcome, and treatment of traumatic brain injuries (TBIs) has favored time of consciousness criteria indicative of hemispheric blast focus alone. However, recent animal-based research has widely expanded the diagnostic knowledge base and potential treatment options. METHODS: Recent animal-based research findings of foramen magnum and occipital crest-focused blast injuries in laboratory rats were reviewed and compared to the Part I human case report. RESULTS: Comparing the human case report (Part I) to that of animal research studies found very similar neuropathological outcomes, many deep and delayed, and supports why non-cerebral-focused TBIs have gone unrecognized. The overpressure wave is funneled through skull openings of the foramen magnum, with the possibility of a rebound secondary contrecoup injury impacting the orbits, oral-nasal cavity, and ears resulting in additional occult axonal and white matter injury. CONCLUSIONS: Research analysis prompted by a human case report (Part I) has helped identify mechanisms that assist in recognizing and defining non-cerebral hemispheric-focused TBI injuries. Position of the head in relationship to the blast wave, the setting in which the blast occurs, and close diagnostic follow-up are critical to the recognition, diagnosis, and treatment of injuries that have otherwise gone unrecognized and unstudied in humans since the Vietnam War.

Delayed-Onset Neuropathological Complications From a Foramen Magnum and Occipital Crest Focused Traumatic Brain Injury of the Vietnam War and Other Conflicts: Part I, Case Report.

INTRODUCTION: The diagnosis of traumatic brain injuries is typically based on hemispheric blasts resulting in degrees of unconsciousness and associated cerebral injuries. This case report describes a Vietnam War era setting in which a traumatic blast wave struck the posterior cranium in the region of the foramen magnum, occipital crest, and other skull openings (orbit, oronasal, and ear) and the unique secondary clinical signs and symptoms experienced over time. MATERIALS AND METHODS: This case report describes secondary delayed-onset clinical signs and symptoms consistent with progressive decades-long physical and functional complications. The traumatic blast resulted in brief unconsciousness, decreased vision in left eye, confusion, right sided hemotympanum, deafness, severe tinnitus, severe nasopharynx pain and difficulty swallowing, pain in right posterior and occipital area of the head, and loss of dental amalgams. Subsequent exams revealed progressive hyperacusis, sea sickness, dysdiadochokinesis, diagnosis of 9th and 10th cranial nerve traumatic schwannomas, hyperdense changes to the frontal lobe white matter, progressive tinnitus, chronic vertigo, right-sided high-frequency hearing loss, progressive oculo-gyric crisis of Tumarkin-like seizures, left-sided chronic vitreous hemorrhage, and diminished right hemisphere performance of the brain based on neurophysiological assessment. No post-traumatic stress, depression, or other emotional or psychiatric difficulties were claimed. CONCLUSION: This case report, unique to the English language scientific literature, discusses in detail the secondary signs and symptoms of a foramen magnum and occipital crest focused-associated blast injury.

Delayed-Onset Neuropathological Complications From a Foramen Magnum and Occipital Crest Focused TBI of the Vietnam War and Other Conflicts: Part III, Critique of Existing TBI Criteria and Their Operational Controversies.

INTRODUCTION: In this report, we discuss the controversy of the diverse traumatic brain injury (TBI) categorization and taxonomy and the need to develop a new multidimensional and multidisciplinary categorization system that can be an aid in improved diagnostic and prognostic outcomes. Of interest, the heterogeneity of TBI marks the major obstacle to develop effective therapeutic interventions. Currently, the Glasgow Coma Scale has been utilized to guide in the prognosis and clinical management of TBI; it does not encompass the pathophysiological mechanisms leading to neurological deficits that can impede therapeutic interventions and consequently the failure of clinical trials. An unfortunate gap exists between advances in TBI research and existing U.S. Department of Defense (DoD) definitions, categorization, and management. Part I illustrates a unique posterior-focused TBI case report that does not fit any existing TBI definitions. Part II summarizes new animal-based TBI research that supports the case report as a legitimate TBI category. Part III critiques existing TBI criteria and their controversies. METHODS: Current DoD definitions and decision-making protocols based on concussion time alone are reviewed and compared to the myriad of additional TBI definitions that further illustrate the marked differences in definitions, especially in mild TBIs. RESULTS: The DoD definitions are not consistent with what academic research and science bring to the debate. With increasing world conflicts and wars, evaluators are not prepared to accept, evaluate, and properly manage those TBIs that are not associated with immediate levels of unconsciousness alone as the prime determinant of diagnosis and long-term severity. Despite comprehensive research, current understanding among decision-makers of progressive pathology of non-hemispheric TBIs remains limited, inconsistent, and confusing. CONCLUSIONS: This dilemma requires a multidisciplinary, science/medicine-led panel to actively reassess TBI criteria that take into consideration the latest research including non-cerebral hemispheric injuries. We recommend that DoD/Veterans Affairs establish a commission to regularly review the academic-related scientific evidence and incorporate these findings in a timely fashion into their operational definitions. This would guarantee that recognition, diagnosis, and follow-up of all TBIs are properly understood, managed, and documented.

Infratemporal fossa approach to the hypoglossal canal: practical landmarks for elusive anatomy.

OBJECTIVE: At the conclusion of the article the readers should be able to safely and reliably find the hypoglossal canal using the infratemporal fossa approach. HYPOTHESIS: Very little has been written on the regional anatomy of the hypoglossal canal as seen through a transtemporal approach. This project attempts to further define the anatomy of the hypoglossal canal and provide the surgeon with guidelines for reaching it. Our hypothesis is that the hypoglossal canal can be safely and consistently reached by way of the temporal bone with preservation of hearing and cranial nerves (CN) IX to XI. STUDY DESIGN: Prospective anatomic study. METHODS: The study was performed using cadaver temporal bones. Infratemporal fossa Fisch type-A dissections were performed. The hypoglossal canal was then completely exposed. The distance from the canal to the jugular bulb, carotid artery, round window, lateral canal, and roots of CN IX to XI were recorded. RESULTS: Fifteen temporal bones were dissected and measured. The position of the hypoglossal canal is consistently located anterior, inferior, and medial to the jugular bulb. The distance from midcanal to the jugular bulb and the roots of CN IX to XI at the posterior fossa dura was 5.3 mm +/- 0.82 and 7.1 mm +/- 2.49, respectively. The distance from the carotid artery where it meets the jugular vein to the midcanal was 15.3 mm +/- 2.09. The distance from the round window to the canal was 21.7 mm +/- 3.17. CONCLUSIONS: The hypoglossal canal can be consistently reached using the infratemporal fossa approach. Hearing and CN IX to XI can be preserved. The distance from the jugular bulb and roots of CN IX to XI can be used as guideposts. If a tumor is involving the bulb, then the carotid artery and the round window are the next most reliable indicators of position.