Post-Traumatic, Drug-Resistant Epilepsy and Review of Seizure Control Outcomes from Blinded, Randomized Controlled Trials of Brain Stimulation Treatments for Drug-Resistant Epilepsy.

BACKGROUND: Many post-traumatic epilepsy (PTE) patients become resistant to medications. Nervous stimulation as a treatment for drug-resistant epilepsy (DRE) is an active area of clinical investigation. OBJECTIVE: To summarize methods, reported seizure control outcome measures, and adverse events from blinded, randomized control trials (RCTs) for selected invasive brain stimulation (IBS) and non-invasive brain stimulation (NIBS) treatment options in patients with DRE. METHODS: PubMed was searched for articles from 1995-2014, using search terms related to the topics of interest. Available relevant articles reporting the outcomes of interest were identified and data was extracted. Articles in the reference lists of relevant articles and clinicaltrials.gov were also referenced. RESULTS: Eleven articles were analyzed with a total of 795 patients identified. Studies showed that select nervous stimulation treatments significantly reduced seizure frequency in patients with DRE.

Use of a Minimally Invasive Retractor System for Retrieval of Intracranial Fragments in Wartime Trauma.

OBJECTIVE: Wartime penetrating brain injury can result in deep-seated parenchymal and intraventicular shrapnel, bullets, and bone. Large fragments pose a risk of secondary injury from migration, infection, and metal toxicity. It has been recommended that aggressive removal of fragments be avoided. The goal of this study is to report our technique of minimally invasive removal of select deep-seated fragments using a tubular retractor system. METHODS: A retrospective review of our database of service members presenting with penetrating traumatic brain injuries incurred during Operations Iraqi Freedom and Enduring Freedom and treated at the Walter Reed Army Medical Center and the National Naval Medical Center was performed. Six individuals were identified in which the Vycor ViewSite retractor system (Vycor Medical, Boca Raton, Florida, USA) was used to remove a ventricular or deep intraparenchymal fragment. All patients were male and ranged in age from 21 to 29 years. Fragment location included the foramen of Monro; the atrium of the right lateral ventricle; parasagittally within the right occipital lobe; the occipital horn of the right lateral ventricle; the deep white matter of the dominant temporal lobe; and within the posterior right temporal lobe deep to the junction of the transverse and sigmoid dural venous sinuses. Fragments included in-driven bone, shrapnel from improvised explosive devices, and bullets. RESULTS: In all cases the fragment was successfully removed. No patient had worsening of their neurologic condition following surgery. CONCLUSION: Deep parenchymal and intraventricular fragments can be safely removed using a tubular retractor system.

Impalement brain injury from steel rod causing injury to jugular bulb: case report and review of the literature.

BACKGROUND: The management of impalement penetrating brain injuries (IPBI) from non-missile objects is extremely challenging, especially when vascular structures are involved. Cerebral angiography is a crucial tool in initial evaluation to assess for vascular injury as standard non-invasive imaging modalities are limited by foreign body artifact, especially for metallic objects. CASE STUDY: This study reports a case of an IPBI caused by a segment of steel rebar resulting in injury to the left jugular bulb and posterior temporal lobe. It describes the initial presentation, radiology, management and outcome in this patient and reviews the literature of similar injuries.

Triage and management of cranial injuries.

This article discusses basic head and intracranial CNS anatomy, cerebral physiology, and classifications of head injury. Management principles and the practice of head-injury evaluation are reviewed and supplemented by the presentation of selected head-injury scenarios. The optimal evaluation and treatment of the head-injured patient is predicated on initially following established ATLS principles and preventing secondary injury. Once specific injuries have been identified, maintenance of cerebral perfusion and oxygenation is the key to maximizing patient outcomes, and this often requires measurement and treatment of ICP values. When significant mass lesions are identified or ICP elevations become refractory to medical intervention, surgical intervention is necessary.

Cerebral hemodynamic changes after wartime traumatic brain injury.

Traumatic brain injury (TBI) is associated with the severest casualties from Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). From October 1, 2008, the U.S. Army Medical Department initiated a transcranial Doppler (TCD) ultrasound service for TBI; included patients were retrospectively evaluated for TCD-determined incidence of post-traumatic cerebral vasospasm and intracranial hypertension after wartime TBI. Ninety patients were investigated with daily TCD studies and a comprehensive TCD protocol, and published diagnostic criteria for vasospasm and increased intracranial pressure (ICP) were applied. TCD signs of mild, moderate, and severe vasospasms were observed in 37%, 22%, and 12% of patients, respectively. TCD signs of intracranial hypertension were recorded in 62.2%; 5 patients (4.5%) underwent transluminal angioplasty for post-traumatic clinical vasospasm treatment, and 16 (14.4%) had cranioplasty. These findings demonstrate that cerebral arterial spasm and intracranial hypertension are frequent and significant complications of combat TBI; therefore, daily TCD monitoring is recommended for their recognition and subsequent management.

Outcomes of 33 patients from the wars in Iraq and Afghanistan undergoing bilateral or bicompartmental craniectomy.

OBJECT: There are no published long-term data for patients with penetrating head injury treated with bilateral supratentorial craniectomy, or supra- and infratentorial craniectomy. The authors report their experience with 33 patients treated with bilateral or bicompartmental craniectomy from the ongoing conflicts in Iraq and Afghanistan. METHODS: An exploratory analysis of Glasgow Outcome Scale (GOS) scores at 6 months in 33 patients was performed. Follow-up lasting a median of more than 2 years was performed in 30 (91%) of these patients. The association of GOS score with categorical variables was explored using the Wilcoxon rank-sum test or Kruskal-Wallis analysis of variance. The Spearman correlation coefficient was used for ordinal/continuous data. To provide a clinically meaningful format to present GOS scores with categorical variables, patients with GOS scores of 1-3 were categorized as having a poor outcome and those with scores of 4 and 5 as having a good outcome. This analysis does not include the patients who died in theater or in Germany who underwent bilateral decompressive craniectomy because those figures have not been released due to security concerns. RESULTS: All patients were men with a median age of 24 years (range 19-46 years) and a median initial Glasgow Coma Scale (GCS) score of 5 (range 3-14). At 6 months, 9 characteristics were statistically significant: focus of the initial injury, systemic infection, initial GCS score, initial GCS score excluding patients with a GCS score of 3, GCS score on arrival to the US, GCS score on dismissal from the medical center, Injury Severity Score, and patients with cerebrovascular injury. Six factors were significant at long-term follow-up: focus of initial injury, systemic infection, initial GCS score excluding patients with a GCS score of 3, GCS score on arrival to the US, and GCS score on dismissal from the medical center. At long-term follow-up, 7 (23%) of 30 patients had died, 5 (17%) of 30 had a GOS score of 2 or 3, and 18 (60%) of 30 had a GOS score of 4 or 5. CONCLUSIONS: In this selected group of patients who underwent bilateral or bicompartmental craniectomy, 60% are independent at long-term follow-up. Patients with bifrontal injury fared best. Systemic infection and cerebrovascular injury corresponded with a worse outcome.

The evolution of the treatment of traumatic cerebrovascular injury during wartime.

The approach to traumatic craniocervical vascular injury has evolved significantly in recent years. Conflicts prior to Operations Iraqi and Enduring Freedom were characterized by minimal intervention in the setting of severe penetrating head injury, in large part due to limited far-forward resource availability. Consequently, sequelae of penetrating head injury like traumatic aneurysm formation remained poorly characterized with a paucity of pathophysiological descriptions. The current conflicts have seen dramatic improvements with respect to the management of severe penetrating and closed head injuries. As a result of the rapid field resuscitation and early cranial decompression, patients are surviving longer, which has led to diagnosis and treatment of entities that had previously gone undiagnosed. Therefore, in this paper the authors' purpose is to review their experience with severe traumatic brain injury complicated by injury to the craniocervical vasculature. Historical approaches will be reviewed, and the importance of modern endovascular techniques will be emphasized.

Neurovascular anatomy: a practical guide.

Students of cerebrovascular anatomy and physiology tend to model their learning based on normal patterns of blood flow. As such, the focus tends toward arterial physiology and pathology with less than adequate understanding of the significance of the venous system. This article presents a different approach to neurovascular anatomy, starting with the venous system and demonstrating both normal and pathologic states. It reviews the cerebral circulation with attention to the microsurgical relationships, angiographic patterns, and fusion of dual-volume imaging. The importance of bony, sulcal, and ventricular anatomy is presented as it relates to the angiographic representation of pathologic lesions. Examples are given of anatomic variants seen with the operating microscope, biplanar angiography, and three-dimensional rotational angiography." Note that in the synopsis and throughout the article, first person usage has been changed to third person per journal style.

Techniques and devices in neuroendovascular procedures.

The management of patients who have cerebrovascular disorders is challenging. Historically, treatments have been limited to medical therapy and open surgical procedures. Our current ability to treat complex vascular disorders in a minimally invasive fashion is improving at a remarkable rate because of advances in neuroendovascular technology. As treatment options in patients with cerebral aneurysms, cerebral arteriovenous malformations, ischemic stroke, and intracranial stenosis continue to increase, patient morbidity and mortality continue to decline. This article reviews and discusses many of the currently available techniques and devices in the neuroendovascular arena.

Role of hyperbaric oxygen therapy in the treatment of bacterial spinal osteomyelitis.

OBJECT: Hyperbaric oxygen therapy (HBO) is used as primary and/or adjunctive therapy in the treatment of various clinical conditions complicated by local hypoxia. It may have therapeutic potential in the treatment of neurosurgical infections such as spinal osteomyelitis that are associated with significant morbidity rates. The purpose of this study was to evaluate the efficacy of HBO therapy in the treatment of spinal osteomyelitis. METHODS: The clinical records of patients diagnosed with spinal osteomyelitis who received HBO therapy during their treatment at the authors' institution over the past 10 years were retrospectively reviewed. Six adult patients were identified. Four patients had recently undergone spinal surgery and secondary spinal osteomyelitis had developed. These patients received adjunctive HBO therapy due to significant comorbidities and risk factors for poor healing. RESULTS: All patients remained symptom and infection free over the subsequent follow-up period. Two patients had primary spinal osteomyelitis that had recurred despite a full course of appropriate antimicrobial therapy. Infection control was achieved after HBO therapy in 1 patient. The mean follow-up period for the study group was 2.9 years (range 5 months to 5 years). CONCLUSIONS: Hyperbaric oxygen therapy enabled infection cure in 5 of 6 patients with spinal osteomyelitis complicated by medical comorbidities or the failure of primary therapy. These results show that HBO may be a useful adjunctive therapeutic modality in the treatment of spinal osteomyelitis, particularly when there are medical comorbidities that increase the risk of poor healing. Hyperbaric oxygen therapy may also be beneficial in patients with relapsing primary spinal osteomyelitis after standard therapy has failed.

Seizure termination by acidosis depends on ASIC1a.

Most seizures stop spontaneously; however, the molecular mechanisms that terminate seizures remain unknown. Observations that seizures reduced brain pH and that acidosis inhibited seizures indicate that acidosis halts epileptic activity. Because acid-sensing ion channel 1a (ASIC1a) is exquisitely sensitive to extracellular pH and regulates neuron excitability, we hypothesized that acidosis might activate ASIC1a, which would terminate seizures. Disrupting mouse ASIC1a increased the severity of chemoconvulsant-induced seizures, whereas overexpressing ASIC1a had the opposite effect. ASIC1a did not affect seizure threshold or onset, but shortened seizure duration and prevented seizure progression. CO2 inhalation, long known to lower brain pH and inhibit seizures, required ASIC1a to interrupt tonic-clonic seizures. Acidosis activated inhibitory interneurons through ASIC1a, suggesting that ASIC1a might limit seizures by increasing inhibitory tone. Our results identify ASIC1a as an important element in seizure termination when brain pH falls and suggest both a molecular mechanism for how the brain stops seizures and new therapeutic strategies.

Functional connections within the human inferior frontal gyrus.

The highly convoluted and cytoarchitectonically diverse inferior frontal gyrus (IFG) of humans is known to be critically involved in a wide range of complex operations including speech and language processing. The neural circuitry that underlies these operations is not fully understood. We hypothesized that this neural circuitry includes functional connections within and between the three major IFG subgyri: the pars orbitalis, pars triangularis, and pars opercularis. To test this hypothesis we employed electrical stimulation tract-tracing techniques in 10 human patients undergoing surgical treatment for intractable epilepsy. The approach involved delivering repeated bipolar electrical stimuli to one site on the IFG while recording the electrical response evoked by that stimulus from a 64-contact grid overlying more distant IFG sites. In all subjects, stimulation of a site on one subgyrus evoked polyphasic potentials at distant sites, either on the same subgyrus or on an adjacent subgyrus. This provided prima facie evidence for a functional connection between the site of stimulation and the sites of the evoked response. The averaged evoked potentials tended to aggregate as response fields. The spatial spread of a response field indicated a divergent projection from the site of stimulation. When two or more sites were stimulated, the resulting evoked potentials exhibited different waveforms while the respective response fields could overlap substantially, suggesting that input from multiple sites converged but by engaging different neural circuits. The earliest deflection in the evoked potential ranged from 2 to 10 msec. No differences were noted between language-dominant and language-nondominant hemispheres.

Hearing suppression induced by electrical stimulation of human auditory cortex.

In the course of performing electrical stimulation functional mapping (ESFM) in neurosurgery patients, we identified three subjects who experienced hearing suppression during stimulation of sites within the superior temporal gyrus (STG). One of these patients had long standing tinnitus that affected both ears. In all subjects, auditory event related potentials (ERPs) were recorded from chronically implanted intracranial electrodes and the results were used to localize auditory cortical fields within the STG. Hearing suppression sites were identified within anterior lateral Heschl's gyrus (HG) and posterior lateral STG, in what may be auditory belt and parabelt fields. Cortical stimulation suppressed hearing in both ears, which persisted beyond the period of electrical stimulation. Subjects experienced other stimulation-evoked perceptions at some of these same sites, including symptoms of vestibular activation and alteration of audio-visual speech processing. In contrast, stimulation of presumed core auditory cortex within posterior medial HG evoked sound perceptions, or in one case an increase in tinnitus intensity, that affected the contralateral ear and did not persist beyond the period of stimulation. The current results confirm a rarely reported experimental observation, and correlate the cortical sites associated with hearing suppression with physiologically identified auditory cortical fields.