The Meniere attack: an ischemia/reperfusion disorder of inner ear sensory tissues.

We believe Meniere attacks arise as a chance association of endolymphatic hydrops and vascular risk factors for intracerebral ischemia. Hydrops acts as a variable Starling resistor upon the inner ear vasculature that is capable of inducing ischemic attacks only in people with reduced perfusion pressure in the ear. The unique characteristics of the attacks (loss of vestibular response and hearing acutely followed by a return to apparent normalcy over hours) are explained by the differential sensitivity of the inner ear tissues to transient ischemia, with the sensory tissues (dendrites, hair cells) vulnerable to hours-long ischemia/reperfusion injury, and the stria vulnerable to ischemia due to its high metabolic rate. Permanent hearing loss and vestibular damage after many attacks would result when small areas of irreversible sensory cell damage accumulate and become confluent. This theory is supported by the strong correlation of hydrops with Meniere attacks, the finding that autoregulation of cochlear blood flow is impaired in the hydropic ear, and studies demonstrating that symptoms and signs in people and in animal models vary with conditions that alter perfusion pressure in the inner ear. Induction of Meniere attacks in animal models requires both hydrops and a mechanism that reduces perfusion pressure, such as epinephrine injection or head dependency. There is a strong clinical association between Meniere attacks and disorders that increase the risk for cerebrovascular ischemia, such as migraine. The excitable tissues in the sensory structures have long been known to be more vulnerable to ischemia than the remaining aural tissues, and are now known to be vulnerable to excitotoxicity induced by ischemia/reperfusion. This correlates well with autopsy evidence of damage to dendrites and hair cells and with strial atrophy in late Meniere disease cases. If this hypothesis is confirmed, treatment of vascular risk factors may allow control of symptoms and result in a decreased need for ablative procedures in this disorder. If attacks are controlled, the previously inevitable progression to severe hearing loss may be preventable in some cases.

Osteochondroma of the convexity: pathologic-neuroimaging correlates of a lesion that mimics high-grade meningioma.

Intracranial chondromas are uncommon benign lesions usually attached to dura and located over the convexity of the skull. Osteochondromas are even rarer and additionally contain a benign bony component. Both lesions are reportedly difficult to distinguish from meningiomas on pre-operative neuroimaging studies, although few detailed pathologic-neuroimaging correlation studies have appeared in the literature, particularly for intracranial osteochondromas. A 33-year-old woman with a 4-year history of headaches presented with recent onset of left-sided muscle spasms and weakness. Two days prior to admission to our hospital, neuroimaging studies had shown a large right convexity mass with unusual multifocal bright signal intensities throughout an otherwise isointense mass. The bright signals were interpreted as showing multifocal hemorrhage and the mass was felt to be a convexity meningioma. However, subsequent catheter angiography characterized the lesion as being avascular. The mass was resected en bloc. Extensive histological sectioning revealed a benign osteochondroma predominantly composed of lobules of hypocellular cartilage. Microdissection of the different components revealed that the multifocal, spicule-like bright foci interpreted as hemorrhage on neuroimaging studies were instead foci of benign bone containing metaplastic bone marrow with trilineage hematopoietic cell populations and adipose tissue. Centrally, the hilum of the lesion contained avascular loose connective tissue. No recent or remote hemorrhage was identified anywhere in the lesion. Rare convexity osteochondromas may be mistaken for high-grade meningiomas on neuroimaging studies; their avascular nature, coupled with their complex signal pattern can serve as clues to the correct pre-operative diagnosis.

Neoplasms involving the central nervous system in the older old.

Geriatric cancer patients present special challenges for clinicians. Few large series have been published in the last 20 years on the types of neoplasms that involve the central nervous system (CNS) in older individuals. To review types of neoplasms involving the central CNS that are currently being encountered by pathologists and neurosurgeons, we identified from our databases for the years 1992-2002, inclusive, patients 75 years or older who had symptomatic lesions requiring neurosurgical interventions. Retrospective characterization of tumors by immunohistochemistry, in situ hybridization, and fluorescence in situ hybridization was performed whenever possible and relevant to tumor type. Neurosurgical procedures (n=125) on 119 patients were identified; 90 patients were diagnosed as having neoplasms, with clot evacuation or infections being the most frequent non-neoplastic conditions necessitating surgery. Tumor types included glioblastomas (36 patients), meningiomas (16), pituitary adenomas (12), lymphomas or other hematological malignancies (8), anaplastic gliomas (5), metastases (6), head and neck malignancies with direct intracranial extension (3), and other miscellaneous tumor types (4). Compared with older literature series, we encountered a larger number of elderly patients with CNS lymphomas and fewer who came to surgery for CNS metastatic disease. In the "older old", glioblastomas are the most frequent symptomatic tumors necessitating surgical intervention. Glioblastomas in this aged cohort display the signature features of the small cell phenotype (62%), high cell cycle labeling indices (mean MIB-1-labeling index=25.1%), and either amplification of epidermal growth factor receptor or gain of chromosome 7 by fluorescence in situ hybridization (93% of assessable cases).

Cognition following bilateral implants of embryonic dopamine neurons in PD: a double blind study.

OBJECTIVES: To determine if bilateral transplantation of embryonic mesencephalic dopamine cells into the putamen of patients with PD significantly affected their cognitive functioning when compared with patients receiving sham surgery and to examine the effect of age on cognitive performance after implantation. METHODS: Forty patients (19 women, 21 men; age 34 to 75 years) with idiopathic PD of at least 7 years' duration (mean 14 years) who had disabling motor signs despite optimal drug management were randomly assigned to tissue implants or sham craniotomies in a double-blind design. Neuropsychological tests assessing orientation, attention, language, verbal and visual memory, abstract reasoning, executive function, and visuospatial and construction abilities were administered before and 1 year after surgery. Treatment groups did not differ at baseline in demographic, neuropsychological, motor, depression, or levodopa equivalent measures. RESULTS: Postsurgical change in cognitive performance was not significantly different for real or sham surgery groups. Performance in both groups remained unchanged at follow-up for most measures. CONCLUSIONS: Embryonic dopamine producing neurons can be implanted safely into the putamen bilaterally without impairing cognition in patients with PD, but within the first year, improved cognition should not be expected.

Transplantation of embryonic dopamine neurons for severe Parkinson's disease.

BACKGROUND: Transplantation of human embryonic dopamine neurons into the brains of patients with Parkinson's disease has proved beneficial in open clinical trials. However, whether this intervention would be more effective than sham surgery in a controlled trial is not known. METHODS: We randomly assigned 40 patients who were 34 to 75 years of age and had severe Parkinson's disease (mean duration, 14 years) to receive a transplant of nerve cells or sham surgery; all were to be followed in a double-blind manner for one year. In the transplant recipients, cultured mesencephalic tissue from four embryos was implanted into the putamen bilaterally. In the patients who received sham surgery, holes were drilled in the skull but the dura was not penetrated. The primary outcome was a subjective global rating of the change in the severity of disease, scored on a scale of -3.0 to 3.0 at one year, with negative scores indicating a worsening of symptoms and positive scores an improvement. RESULTS: The mean (+/-SD) scores on the global rating scale for improvement or deterioration at one year were 0.0+/-2.1 in the transplantation group and -0.4+/-1.7 in the sham-surgery group. Among younger patients (60 years old or younger), standardized tests of Parkinson's disease revealed significant improvement in the transplantation group as compared with the sham-surgery group when patients were tested in the morning before receiving medication (P=0.01 for scores on the Unified Parkinson's Disease Rating Scale; P=0.006 for the Schwab and England score). There was no significant improvement in older patients in the transplantation group. Fiber outgrowth from the transplanted neurons was detected in 17 of the 20 patients in the transplantation group, as indicated by an increase in 18F-fluorodopa uptake on positron-emission tomography or postmortem examination. After improvement in the first year, dystonia and dyskinesias recurred in 15 percent of the patients who received transplants, even after reduction or discontinuation of the dose of levodopa. CONCLUSIONS: Human embryonic dopamine-neuron transplants survive in patients with severe Parkinson's disease and result in some clinical benefit in younger but not in older patients.

An overview of central nervous system transplantation in human disease.

Although its roots date back over a century, the field of neurotransplantation has been shaped mostly by advances over the past 30 years. Animal models of nigrostriatal disconnection in the 1970s allowed investigators to explore the feasibility of neural grafting. By the end of that decade, functional and behavioral effects had been demonstrated using fetal tissue grafts. In the 1980s, animal experimentation continued, as did clinical trials involving patients with idiopathic Parkinson's disease. Both autologous adrenal medullary tissue and fetal allografts were tested in the clinical setting, with the latter proving to yield superior results. Animal models of striatal cell loss provided the impetus for limited clinical trials in patients with Huntington's disease by the early 1990s, and work with both diseases continues today. Although much has been learned, neural grafting remains experimental. Broader applications are being explored even now, though, as transplant techniques are applied to animal models of dementia, spinal cord injury, cortical injury, and pain. Some very limited human trials have already begun in some of these areas. In this review some of the advances in the field are highlighted.

Outcome after urgent surgery for grade IV subarachnoid hemorrhage.

BACKGROUND: Outcome after subarachnoid hemorrhage (SAH) in patients presenting with poor clinical grade has historically been dismal. As a result, many poor-grade patients have been excluded from early, aggressive surgery. We present a consecutive series of 27 patients with acute (less than 24 h since clinical onset) Grade IV SAH treated with early surgery. METHODS: All patients were treated with immediate ventricular drainage, rigid hemodynamic control, early angiography and surgery within 24 h of presentation. Patients were followed for a minimum of 6 months and their outcomes categorized using a four-tiered scale: 1) independent and working, 2) impaired but independent, 3) severely impaired and dependent, and 4) dead. RESULTS: Seven patients died within 48 h of admission. The remaining 20 patients survived to discharge. At the time of discharge eight of these patients were considered to be impaired but independent and twelve were considered severely impaired and dependent. At follow-up, seven patients were independent and working, six were impaired but independent, five were severely impaired and dependent, and two severely impaired patients had subsequently died. CONCLUSIONS: We conclude that urgent surgery for poor-grade SAH can produce quality survival for a higher percentage of patients than is historically reported with delayed surgery.

Incidence of unsuspected blunt carotid artery injury.

OBJECTIVE: This study attempts to document the incidence of unsuspected blunt carotid artery injury (BCI) in a prospective series of consecutive blunt trauma patients undergoing angiographic evaluation of the aorta. Previous studies have included mainly patients who became symptomatic from BCI, thus documenting a "detected incidence." METHODS: During a 22-month period, all patients undergoing angiographic evaluation of the aorta after blunt trauma who were not felt to be at increased risk for BCI were included in the screening protocol. All patients initially suspected of BCI were studied outside the protocol. Angiographic evaluation of the carotid arteries was performed using nonselective contrast injections after aortic injury had been ruled out. RESULTS: The incidence of BCI among those patients screened under the protocol (n = 119) was 2.5% (3 of 119). Among all patients undergoing aortic evaluation at presentation (n = 171), the detected incidence of BCI was 3.5% (6 of 171). The detected incidence of BCI among all patients during the study period was 0.32% (10 of 3174). No risk factors for BCI were identified beyond the severity of trauma that led to aortic evaluation. CONCLUSION: The incidence of BCI found in those patients screened in this study, nearly 10 times the incidence of BCI in our blunt trauma population overall, suggests that these patients represent a subgroup on which to focus screening efforts, regardless of the diagnostic tools employed. The similarity between the angiographic incidence and the detected incidence of BCI in this study argues that few BCIs remain asymptomatic. All blunt trauma patients injured sufficiently to prompt aortic evaluation at presentation should be screened in some manner for BCI.

Unusual dural and skull-based mesenchymal neoplasms: a report of four cases.

Dural and skull-base mesenchymal neoplasms other than meningiomas are rare. We report four such tumors, some of which are uncommon even in nonintracranial sites, in three adults and one child. The adult tumors consisted of a synovial sarcoma of the third ventricle region in a 19-year-old woman, a leiomyoma of the suprasellar region in a 57-year-old woman, and an Epstein-Barr virus (EBV)-associated smooth muscle tumor of the cavernous sinus in a 35-year-old woman with acquired immunodeficiency syndrome (AIDS). The pediatric tumor was an EBV-associated leiomyosarcoma of the left dural transverse sinus in a 14-year-old girl with common variable immunodeficiency syndrome. All tumors were thought to be primary in their dural or skull-base locations. The two EBV-associated smooth muscle tumors in immunocompromised patients expand the locations for EBV-associated smooth muscle tumors to dural and skull-base sites, the synovial sarcoma is unique to the intracranial space, and the sellar leiomyoma represents the third reported sellar smooth muscle tumor.

Induced hypervolemia and inotropic support for acute cerebral arterial insufficiency: an underused therapy.

BACKGROUND: Hypervolemia and induced systemic hypertension are generally considered the standard approach to the treatment of vasospasm. Despite evidence in favor of its efficacy, this therapy is used rarely in acute cerebrovascular occlusion. We present a case supporting this treatment paradigm. CASE DESCRIPTION: A patient developed aphasia and hemiplegia 8 h after carotid endarterectomy caused by embolic occlusion of the middle cerebral artery. Hyperdynamic/hypervolemic therapy was instituted. Serial angiograms filmed over the next 8 h demonstrated reperfusion of the hemisphere, through collateral flow. The patient's symptoms resolved. CONCLUSIONS: We believe this case demonstrates the effectiveness of hypervolemia and inotropic support in the treatment of acute embolic stroke by inducing dilatation of the leptomeningeal collateral circulation.

T2-weighted three-dimensional turbo spin-echo MR of intracranial aneurysms.

A T2-weighted three-dimensional turbo spin-echo sequence is described that accurately depicted the anatomy of 18 intracranial aneurysms in 10 patients.

Pineal region choroid plexus papilloma treated with stereotactic radiosurgery: a case study.

The treatment of a patient with a third-ventricular choroid plexus papilloma is described. This relatively unusual lesion was treated with stereotactic radiosurgery. Follow-up at 17 months demonstrates substantial reduction in tumor volume and an excellent clinical outcome. The treatment of this patient suggests that radiosurgery may be an effective alternative to open surgical resection.

Genotypic variations of type III collagen in patients with cerebral aneurysms.

It has been hypothesized that either qualitative or quantitative abnormalities in type III collagen may be involved in the pathogenesis of cerebral aneurysms. The current study investigated allele frequencies for the type III collagen gene in patients with cerebral aneurysms. A diallelic Ava II polymorphism defined the type III collagen gene. The smaller of the two alleles was found in 11 of 19 aneurysm patients (58%) versus two of 15 controls (13%) (p = .006). The overall frequency of this allele was 0.34 in aneurysm patients versus 0.10 in controls (p = .011). This significant difference in allele frequency suggests that genotypic variations in the type III collagen gene may be etiologically related to aneurysm formation.

Rhabdomyolysis following spinal cord injury: case report.

Rhabdomyolysis is commonly seen in association with multisystem trauma. We report an unexpected case of rhabdomyolysis and subsequent renal insufficiency after spinal cord injury unassociated with acute muscular injury. Immobilization, in conjunction with mild systemic hypoperfusion, was the suspected cause. Due to the likelihood of muscle catabolism, the difficulties of diagnosing soft tissue injury, and the impact of any decrease in renal reserve in patients with spinal cord injuries, surveillance for laboratory evidence of rhabdomyolysis in patients with neurologically complete spinal cord injuries appears warranted.

Traumatic brain injury associated with an intradiploic epidermoid cyst: case report.

We present a case of an intradiploic epidermoid cyst with an unusual complication. After a minor fall, a patient with a large right parietal epidermoid suffered a traumatic brain injury caused by the transfer of the force of the fall through the cyst contents to the brain and by transdural herniation of the cyst contents into brain parenchyma. Elective resection of intradiploic epidermoids associated with large bony defects is recommended to avoid this apparently rare but potentially dangerous complication of an otherwise benign condition.

Implantation of fetal tissue for the management of Parkinson's disease: a technical note.

A relatively simple method for implanting fetal tissue within the human basal ganglia is described. Stereotactic techniques are used to deposit 14 to 16 strands of fetal mesencephalic tissue in a linear array within the putamen bilaterally. To eliminate the need for targeting each needle pass independently, we have devised a novel rotating template/micromanipulator apparatus that can be mounted on a Cosman-Roberts-Wells stereotactic frame. The template contains two parallel columns of nine holes, all spaced at 4-mm intervals. It can be aligned to the longitudinal axis of the putamen and targeted with coordinates for the center point of the putamen. Surgery is performed on an awake patient. Short-term morbidity (4-6 wk) in the form of variability of Parkinsonian signs, particularly "off" symptoms and mild confusion, appears to be the rule with simultaneous bilateral implants.