Perioperative ulnar neuropathies have long been attributed to inappropriate arm positioning and padding during operations and have resulted in many lawsuits.

A recent Canadian lawsuit is described and the literature regarding perioperative ulnar and other focal neuropathies reviewed.

The evidence strongly suggests that ulnar nerve damage is usually sustained in the postoperative rather than the intraoperative period. There is no evidence that positioning or padding of the arm during the operation prevents perioperative ulnar neuropathies.

There should generally be no basis for a claim against medical or nursing staff or hospitals when an ulnar neuropathy develops following anesthesia and surgery.

In Alzheimer’s disease (AD) the olfactory system, including the olfactory bulb, a limbic paleocortex is severely damaged. The occurrence of early olfactory deficits and the presence of senile plaques and neurofibrillary tangles in olfactory bulb were reported previously by a few authors. The goal of the present study was to analyze the occurrence of AD-type degenerative changes in the peripheral part of the olfactory system and to answer the question whether the frequency and severity of changes in the olfactory bulb and tract are associated with those of the cerebral cortex in AD.

In 110 autopsy cases several cortical areas and the olfactory bulb and tract were analyzed using histo- and immunohistochemical techniques. Based on a semiquantitative analysis of cortical senile plaques, neurofibrillary tangles and curly fibers, the 110 cases were divided into four groups: 19 cases with severe (definite AD), 14 cases with moderate, 58 cases with discrete and 19 control cases without AD-type cortical changes.

The number of cases with olfactory involvement was very high, more than 84% in the three groups with cortical AD-type lesions. Degenerative olfactory changes were present in all 19 definite AD cases, and in two of the 19 controls. The statistical analysis showed a significant association between the peripheral olfactory and cortical degenerative changes with respect to their frequency and severity (P<0.001). Neurofibrillary tangles and neuropil threads appear in the olfactory system as early as in entorhinal cortex.

The results indicate a close relationship between the olfactory and cortical degenerative changes and indicate that the involvement of the olfactory bulb and tract is one of the earliest events in the degenerative process of the central nervous system in AD.

Medical students in Canada must make career choices by their final year of medical school. Selection of students for a career in neurosurgery has traditionally been based on marks, reference letters and personal interviews. Studies have shown that marks alone are not accurate predictors of success in medical practice; personal skills and attributes which can best be assessed by letters of reference and interviews may be more important. This study was an attempt to assess the importance of, and ability to teach, personal skills and attitudes necessary for successful completion of a neurosurgical training program.

A questionnaire was sent to 185 active members of the Canadian Neurosurgical Society, asking them to give a numerical rating of the importance of 22 personal skills and attributes, and their ability to teach those skills and attributes. They were asked to list any additional skills or attributes considered important, and rate their ability to teach them.

Sixty-six (36%) questionnaires were returned. Honesty, motivation, willingness to learn, ability to problem solve, and ability to handle stress were the five most important characteristics identified. Neurosurgeons thought they could teach problem solving, willingness to consult informed sources, critical thinking, manual dexterity, and communication skills, but honesty, motivation, willingness to learn and ability to handle stress were difficult or impossible to teach.

Honesty, motivation, willingness to learn, ability to problem solve and handle stress are important for success in a neurosurgical career. This information should be transmitted to medical students at “Career Day” venues. Structuring letters of reference and interviews to assess personal skills and attributes will be important, as those that can’t be taught should be present before the start of training.

To explore the somatosensory cortical responses to natural moving tactile stimulation in adult subjects using magnetoencephalography.

We measured cortical somatosensory magnetic evoked fields (SEFs) to moving tactile stimuli by a brush over the right thumb once every 1.5 s in seven subjects. Electric SEFs with various intensity or simulated jitter were used for comparison.

Tactile SEFs in primary somatosensory cortex (SI) consisted of two deflections: N24mT and P55mT. Electric SEFs consisted of N24mE, P30mE, P40mE, and P55mE. The amplitude of N24mT was only 34% ± 12% of N24mE, whereas P55mT and P55mE were of about the same size. With increased jitter or decreased intensity, attenuation of electric SEFs was more clearly found in early deflection than late deflection.

Natural moving tactile stimulation produced simpler cortical somatosensory waveforms in comparison with electric SEFs, partly related to less sharp intensity and stimulation jitter with moving tactile stimulation. We propose that of all the afferent fibers conveying the early deflection, the low threshold components participate the generation of the late deflection.

To describe the clinical and laboratory findings in cases of neonatal herpes simplex virus (HSV) encephalitis.

Neonatal HSV encephalitis is a devastating infection which requires a high degree of clinical suspicion and rapid initiation of antiviral therapy.

We performed a retrospective search for all cases of HSV encephalitis within the two Saskatchewan pediatric tertiary care centers for the period of 1985-2001. Only those patients with consistent clinical presentations along with direct evidence of presence of HSV, such as positive cerebrospinal fluid (CSF) viral cultures, positive polymerase chain reaction (PCR) for HSV from CSF, or positive immunoglobulin G against HSV from neonatal blood, were selected.

Five male and four female infant patients were identified. At a mean age of presentation of 24±20 days, seizures occurred in six neonates, lethargy in six neonates, temperature changes in five neonates, and apnea in three neonates. Examination of CSF demonstrated an initial monocytosis or lymphocytosis, elevated CSF protein and depressed CSF glucose in 100% of patients. Electroencephalography (EEG) was abnormal in 100% of patients. Initial computerized tomography was abnormal in 55% of patients. Clinical follow-up over an average of two years demonstrated developmental delay in four patients and upper motor neuron findings in four patients. No patients suffered from postencephalitic epilepsy or mortality.

Neonatal HSV encephalitis most commonly presents with seizures, lethargy, and dysthermia. Cerebrospinal fluid testing and EEG have 100% sensitivity in cases with laboratory confirmation of HSV presence. Improvements in morbidity and mortality as compared to previous reports may relate to better recognition of this illness and acyclovir therapy. The lack of postinfection epilepsy in our series may also relate to better recognition and acyclovir therapy within this series of patients.

Human T-cell lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in British Columbian Coastal Natives has, to date, been a clinical and laboratory diagnosis. However, magnetic resonance imaging (MRI) abnormalities have been well-described in other populations in which HAM/TSP is endemic.

In order to assess the usefulness of MRI as a diagnostic tool in this population, we compared scans of HAM/TSP patients with those of HTLV-I positive non-HAM/TSP British Columbian Coastal Natives (carriers) and multiple sclerosis patients presenting with progressive paraparesis.

The typical nonspecific findings of thoracic cord atrophy and increased signal in the periventricular and subcortical white matter on T2-weighted images were confirmed in the HAM/TSP patients. Despite a lack of specificity of the MRI findings between HAM/TSP patients and HTLV-I carriers, criteria that could effectively differentiate HAM/TSP patients from multiple sclerosis patients with similar clinical presentations were determined.

Clinical and radiological correlations suggest that longitudinal MRI investigations charting the course of HAM/TSP may reveal the clinical significance of these lesions and further define the role of MRI in the diagnosis of this entity. Magnetic resonance imaging is an important supplement to immunological and clinical data in differentiating multiple sclerosis from HAM/TSP.

To describe a novel therapeutic strategy for the treatment of “blister-like” aneurysms of the distal internal carotid artery (ICA). Direct surgical treatments of these fragile lesions have been associated with generally poor outcomes.

Two consecutive patients presenting with acute subarachnoid hemorrhage from “blister-like” aneurysms were treated with preliminary balloon occlusion of the ICA, followed by surgical trapping of the ICA beyond the aneurysm.

The treatment resulted in complete thrombosis of both aneurysms with no clinical complications.

This combined endovascular-neurosurgical approach offers a controlled, safer alternative to primary surgical therapy of “blister-like” aneurysms.

Several animal models of cerebral ischemia have been developed to investigate both pathophysiology and pharmacological treatment. The aim of this study was to verify the prognostic value of EEG power spectra analysis in a two-vessel plus hypotension rat model of transient global ischemia.

Spontaneously hypertensive rats (SHRs) and Wistar Kyoto rats (WKYs) were subjected to 20 min bilateral common carotid artery occlusion plus hypotension by sodium nitroprusside followed by reperfusion for seven days. Sham-operated animals served as controls. The changes after ischemia in EEG power spectra, and their relations with neuronal damage and astrocytic response were investigated.

The EEG analysis revealed that in SHRs and WKYs, ischemia produced a dramatic increase in delta activity and a decrease in theta, beta and alpha activities derived from both cortical and hippocampal areas. EEG activity reverted to normal values more quickly in WKYs than in SHRs which did not recover cortical and hippocampal alpha and beta activities even at six days of reperfusion. SHRs presented more severe damage and intense astrocytosis than WKYs in almost all the brain regions analyzed. In SHRs, hippocampal delta activity was positively correlated with the degree of neuronal necrosis and astrocytic activation, whereas theta, alpha and beta activities correlated negatively. No correlations were found in WKYs.

These data indicate that the hippocampal bioelectrical activity recorded in SHRs from the beginning of reperfusion could be useful for predicting the ischemic outcome and evaluating the effects of pharmacological interventions.

Cerebral aneurysms are the predominant cause of spontaneous subarachnoid hemorrhage (SAH). However, if an aneurysmal cause has been excluded, there remains but a short list of other potential etiologies. Cerebral neoplasms are clearly on this list but are most commonly meningiomas or metastatic lesions. This article details a case of a neoplasm that presented exclusively with SAH.

A 40-year-old male presented with a SAH with normal cerebral angiography. The initial magnetic resonance image revealed a lesion in the right insula thought to be resolving hemorrhage. Subsequent images, however, revealed the mass to be enlarging.

Craniotomy and resection of the lesion established a diagnosis of a malignant oligodendroglioma.

An affirmation is made that patients experiencing ’angiographically-negative’ SAH should undergo MRI, occasionally on a serial basis, to exclude other etiologies for hemorrhage, including neoplasia.

The radiographic identification of pineal cysts has increased dramatically within the last two decades due to the advent of magnetic resonance imaging. Pineal cysts are often found incidentally with only a minority of these lesions ever becoming symptomatic and requiring treatment. Many theories attempting to explain the pathogenesis of these cysts exist.

We describe a case of a 12-year-old girl who presents with a pineal hemorrhage of unknown etiology with associated hydrocephalus.

Her hydrocephalus was initially treated with an external ventricular drain followed by a third ventriculostomy. She had no evidence of elevated beta human chorionic gonadotropin or alpha-fetoprotein within the serum or cerebrospinal fluid. Follow-up imaging at seven weeks revealed resolution of her hemorrhage, however, there was development of a progressive cystic lesion within the pineal region. In order to make a definitive tissue diagnosis, a supracerebellar infratentorial surgical approach with complete resection was performed. During the resection, brownish fluid was aspirated from the cyst and the cyst wall was removed. The pathological diagnosis was a pineal cyst.

Although cases have been described of pineal apoplexy with an underlying cyst, this case describes the development of a progressive pineal cyst secondary to a hemorrhage. This case demonstrates that pineal hemorrhage may be a promotor for the development or progression of pineal cysts.

Meningiomas of the anterior cranial fossa frequently present with impaired visual function. Recognition of this entity in the differential diagnosis of painless, progressive, and asymmetric optic neuropathy is important since reversal of visual loss is possible given timely surgical excision of the tumour.

A 76-year-old man presented with no perception of light in his right eye and a reduced visual acuity of 20/60 in his left eye with a markedly constricted visual field. His visual deterioration had progressed over the previous three months and was not associated with headache. Ophthalmoscopy showed normal optic discs. MRI scanning showed a large frontal basal meningioma, which was subsequently resected.

The patient noticed an immediate improvement in his vision in his right eye. Visual acuity in his right eye improved to 20/50 at six weeks postoperatively and to 20/25 at five months, with corresponding improvement of the visual field.

Complete monocular blindness due to tumour compressing or distorting the anterior visual pathways does not preclude recovery following timely decompressive surgery, especially when the appearance of the optic disc is normal.

Organophosphate intoxication can cause some well-known life threatening acute neurological complications such as seizures, paralysis, neuromuscular and cardiac conduction disorders. Less often, a predominantly motor and delayed axonal neuropathy can occur. This syndrome is due to inhibition of neuropathy target esterase.

A 30-year-old woman attempted suicide by drinking approximately 1000mg/kg dimethyl-2,2-dichloro vinyl phosphate (DDVP). After a muscarinic and cholinergic syndrome lasting four days, she developed a purely motor distal axonal polyneuropathy on the fifth week after ingestion confirmed by electroneuromyography and sural nerve biopsy. Neurological examination and electroneuromyography revealed a slight recovery at the end of the 21st month.

This case of late onset polyneuropathy caused by organophosphate intoxication had unusual features such as intact sensory nerves and worse prognosis when compared to previously reported cases.