Intraoperative hyperventilation vs remifentanil during electrocorticography for epilepsy surgery - a case report.

BACKGROUND: Traditionally, intraoperative intracranial electroen-cephalography-recordings are limited to the detection of the irritative zone defined by interictal spikes. However, seizure patterns revealing the seizure onset zone are thought to give better localizing information, but are impractical due to the waiting time for spontaneous seizures. Therefore, provocation by seizure precipitants may be used with the precaution that spontaneous and provoked seizures may not be identical. OBJECTIVE: We present evidence that hyperventilation induced and drug induced focal seizures may arise from different brain regions in the same patient. METHODS: Hyperventilation and ultra short acting opioid remifentanil were used separately as intraoperative precipitatants of seizure patterns, while recording from subdural and intraventricular electrodes in a patient with temporal lobe epilepsy. Two different ictal onset zones appeared in response to hyperventilation and remifentanil. Both zones were resected and the patient has remained essentially seizure free for 1 year. Furthermore, this is the first description of hyperventilation used as an intraoperative seizure precipitant in human focal epilepsy.

Remifentanil-induced spike activity as a diagnostic tool in epilepsy surgery.

OBJECTIVES: To assess the value of remifentanil in intraoperative evaluation of spike activity in patients undergoing surgery for mesial temporal lobe epilepsy (MTLE). MATERIALS AND METHODS: Twenty-five patients undergoing temporal lobectomy for medically intractable MTLE were enrolled in the study. Electrocorticography (ECoG) recordings were performed on the intraventricular hippocampus and from the anterior inferior temporal and lateral neocortex before and after a 300 microg intravenous bolus of remifentanil. Spike activity was quantified as spike-count per minute. RESULTS: A significant increase (P < 0.005) in spike activity was observed after administration of remifentanil in 23 of 25 patients (92%). Furthermore, two patients who did not have any spike activity on the baseline ECoG developed spikes after administration of remifentanil. CONCLUSIONS: The results suggest that remifentanil can enhance spike activity in the epileptogenic zone and reveal otherwise concealed epileptogenic tissue in patients with MTLE. Thus, remifentanil may prove to be an important diagnostic tool during surgical treatment for intractable focal epilepsy.

Dopamine transporter imaging and the effects of deep brain stimulation in patients with Parkinson's disease.

PURPOSE: Single-photon emission computed tomography (SPECT) with [123I]FP-CIT is a marker for loss of presynaptic dopamine transporters in the striatum in Parkinson's disease (PD). We used [123I]FP-CIT SPECT in order to evaluate binding to the dopamine transporter before and after neurosurgical treatment with bilateral stimulation in the subthalamic nucleus (STN). METHODS: Thirty-five patients with levodopa-responsive PD were examined with [123I]FP-CIT SPECT pre-operatively (baseline scan: mean 3 months before surgery), and 3 and 12 months after surgery. RESULTS: Pre-operatively, all patients already had substantial signs of severe nigrostriatal neuronal loss as determined from the [123I]FP-CIT SPECT scans. One year after surgery the specific [123I]FP-CIT binding to the striatum was significantly reduced by 10.3% compared with the pre-operative baseline scan. The mean time span from the baseline scan before surgery to the follow-up scan 1 year after surgery was 16.2 months. Hence, the rate of reduction equals a mean annual reduction of 7.7%. A comparable control group of patients with PD who did not undergo surgery was also examined longitudinally. In this group the specific binding of [123I]FP-CIT was reduced by 6.7% per year. CONCLUSION: The specific binding of [123I]FP-CIT was reduced equally in the STN-stimulated patients and a group of non-operated PD patients with advanced disease. Our study does not support the notion that electrode implantation and STN stimulation exert a neuroprotective effect by themselves.

Papillary glioneuronal tumor--a new tumor entity.

Glioneuronal neoplasms of the CNS comprises a heterogeneous group of generally low-grade tumors expressing glial and neuronal cells of varying differentiation. Recently, a new variant of the glioneuronal tumors has been identified. We present a case of a glioneuronal tumor located in the left frontal lobe of a 16-year-old boy who developed seizures 6 months after brain concussion. MR scan demonstrated an irregular, but well circumscribed, mixed cystic and solid tumor with contrast enhancement in the solid part. Histology showed a papillary glioneuronal tumor. The tumor is indolent with no sign of recurrence after gross total resection.

[Reliability of recorded deaths from asthma in Denmark during a 1-year period 1994-1995]. / Pålideligheden af registrerede asthmadødsfald i Danmark i en 1-års-periode 1994-1995.

INTRODUCTION: The aim of this study was to evaluate the accuracy of death certificates over a one-year period, where asthma was given as the cause of death. METHODS: All medical information available was collected on 218 patients by reviewing hospital records, records from general practitioners, and sometimes by interviewing close relatives. A panel of four pulmonologists each examined the information and independently assessed the cause of death. RESULTS: Thirty-nine were excluded, as the cause of death could not be validated. In 16 (9%) of the subjects, asthma was judged to be the definite cause of death and in 12 (7%) a possible cause. Of 151 non-asthma deaths, but registered as asthma, 109 were judged to have suffered or died from COPD and 14 from heart disease. DISCUSSION: The accuracy of Danish death certification in asthma deaths is poor, especially in the elderly, where COPD is often classified as asthma. We conclude that the true mortality from asthma in Denmark is substantially lower than that officially recorded.

[Long-term oxygen therapy (LTOT) in chronic obstructive lung disease (COL)]. / Langtids oxygenterapi (LTOT) ved kronisk obstruktiv lungesygdom (KOL).

UNLABELLED: A substantive amendment to this systematic review was last made on 12 April 1999. Cochrane reviews are regularly checked and updated if necessary. BACKGROUND AND OBJECTIVES: To determine the effect of domiciliary oxygen therapy on survival and quality of life in patients with chronic obstructive pulmonary disease. SEARCH STRATEGY: Randomised controlled trials (RTCs) were identified using the Cochrane Airways Group Chronic Obstructive Pulmonary Disease (COPD) register using the search terms: home or domiciliary and oxygen. SELECTION CRITERIA: Any randomised controlled trial in patients with hypoxia and chronic obstructive pulmonary disease that compared long term domiciliary or home oxygen therapy with a control treatment. DATA COLLECTION AND ANALYSIS: Data extraction was performed independently by two reviewers. MAIN RESULTS: Four randomised controlled trials were identified. Data from none of these trials could be aggrigated because of differences in trial design and patient selection. Trial 1, continuous oxygen therapy versus nocturnal oxygen therapy: there was a significant improvement in mortality after 24 months (Peto odds ratio 0.45, 95% confidence interval 0.25 to 0.81). Trial 2, oxygen versus no oxygen: there was a significant improvement over five years in mortality in the group receiving oxygen (Peto odds ratio 0.42, 95% confidence interval 0.18 to 0.98). Trial 3, nocturnal oxygen versus no oxygen in patients with arterial desaturation at night: there was no difference in mortality at 36 months. Trial 4, long term oxygen versus no oxygen in moderate hypoxaemia: there was no effect on survival for up to three years of follow up. REVIEWERS' CONCLUSION: Long term oxygen therapy improves survival in a selected group of COPD patients with severe hypoxaemia (arterial PO2 less than 8.0 kPa). Long term oxygen does not appear to improve survival in patients with moderate hypoxia or those who only have arterial desaturation at night.

[An unusual case of intracranial lipomatosis and cerebral aneurysm]. / Et usaedvanligt tilfaelde af intrakraniel lipomatose og cerebralt aneurisme.

An unusual combination of a fusiform aneurysm on the middle cerebral artery branch to the central region and cortical lipomatosis is described. The etiology of lipomatous disorders in the brain are multiple. The possibility of a combined dysplasia based on maldifferentiation of primitive meninges and the arterial wall is suggested in this case. Treatment consisted in uneventful, microsurgical image-guided resection of the aneurysm using the Surgiscope robotic system.

[Neurosurgical treatment of trigeminal neuralgia. A comparative study of alcohol block, neurectomy and electrocoagulation]. / Neurokirurgisk behandling af trigeminusneuralgi. En sammenlignende undersøgelse af alkoholblokade, eksairese og elektrokoagulation.

The objective was to assess the present condition of patients previously treated with neurosurgical procedures for trigeminal neuralgia (TN). Between 1976 and 1991, 383 patients were treated for TN at the Department of Neurosurgery, Hvidovre Hospital. The latest surgical intervention performed was radiofrequency coagulation (64%), neurectomy (18%), alcohol block (16%), trigeminal tractotomy (1%), and microvascular decompression (1%). Questionnaires were sent to 316 patients treated neurosurgically for trigeminal neuralgia during the 16 year period. After radiofrequency coagulation, neurectomy and alcohol block, 83, 51 and 42% respectively experienced a pain free postoperative period. At present 49, 17 and 18% were without pain and 33, 21 and 36% had less pain compared with the preoperative state. Sequelae were described in 65, 57 and 49% of the patients. The four most common sequelae were hypaesthesia, paraesthesia, eye complaints, and dysaesthesia. If relevant pharmacotherapy has been tried without benefit, radiofrequency coagulation may still be considered as a treatment of trigeminal neuralgia.

[Allergen decontamination and public sector]. / Allergisanering og offentlig forvaltning.

Reduction of allergen exposure is one way to reduce exacerbations in allergic asthma. According to Danish legislation, the local authorities have to support initiatives which can reduce clinically relevant inhouse allergen exposure. A case of grotesque bureaucracy and ignorance of basic allergological facts is presented. Local administration confused allergy to cat dander with allergy to house dust mite and two appeal boards only reviewed legal aspects, not medical. After inquiry by the ombudsman, the case was reviewed by one appeal board and the patient was granted help. After three years the patient had moved to another district and the case was started all over again. It is recommended that direct contact between physicians should be preferred, in order to avoid misinterpretation of specialist statements. Original documents should always be requested to avoid transcription errors. Local public administration should respect legislation and improve the quality of their medical advisors.

How many neurosurgeons do we want to educate in Europe annually? The Danish proposal.

The neurosurgical population consists of professors, consultants, specialised senior registrars, and doctors in training (senior registrars, trainees and young doctors to be educated as neurosurgeons). Knowing number and size of the neurosurgical departments in each European country, the number of staff members, the politics of retirement (age, educational level) and the age of every neurosurgeon it is possible to calculate the exact number of trainees needed per year to maintain a state of balance in every single European country. With Denmark as a model we based our assessments partly on a simple calculation model of the exact annual number of neurosurgical trainees or senior registrars and partly used an actuary flow model for calculation. In Denmark with 5 neurosurgical departments, 5.2 mill. population and a retirement age of 70, we have an average of 1-2 newcomers per year and maintain a bulk of 10 senior registrars in education. Thus there will be a balance between intake of newcomers and retirement, of course with some unknown factors as unforeseen dismissal or resignation, death rate among neurosurgeons and transfer to private practice.

Hypoglosso-facial nerve anastomosis.

The hypoglosso-facial nerve anastomosis (HFA) is a valuable surgical procedure for the treatment of certain types of facial paralysis. HFA was performed 1 to 22 months after resection of an acoustic neurinoma in 32 patients where the operation was complicated by unilateral facial palsy. 56% of these patients obtained excellent facial function, and a total of 66% were satisfied and would have repeated the operation even with their present knowledge about the disadvantages. The recovery of facial function after any nerve anastomosis or plastic procedure is never perfect but HFA usually results in symmetry of the face in response and animation of the face during conversation. HFA is most effective when used as soon as possible after facial palsy has developed, provided a sufficient time has passed for any possible spontaneous recovery. This waiting period should not exceed six months. If the operation is done promptly the results improve, probably because only slight atrophy has occurred in the facial muscles. The disadvantages of HFA are hemiatrophy of the tongue, mass movement of the face and, in some instances, hypertonia of the face. The advantages are improved facial tone with ameliorated cosmetic result, protection of the eye, intentional facial movements controlled by the tongue, and movements associated with physiological function of the tongue.

Phosphorous and proton spectroscopy in relation to near incarceration and incarceration of the human brain.

We report 3 cases of 31P and 1H MR spectroscopy (MRS) performed at different stages on patients with clinical signs of near or fulminant incarceration of the brain. The measurements were made on a whole body, 1.5 T scanner. 1H-MRS was obtained with the STEAM sequence and 31P-spectra were obtained using the chemical shift imaging technique. Medical treatment including controlled ventilation and sedation of the patients was carried out during the examination. The first patient was evaluated on days 6 and 10 after evacuation of an acute subdural haematoma. An intracranial pressure of 35 mm Hg was registered during the first examination. The 2nd patient had suffered a spontaneous intracerebral haemorrhage and showed clinical signs of imminent incarceration during the examination. The 3rd patient showed clinical signs of incarceration just prior to the examination. In the 1st patient 1H-MRS showed a 3-fold increase in the concentration of choline-containing compounds and a small decrease in N-acetyl aspartate from the 1st to the 2nd examination, which we interpret as a loss of neurones. In case 2 only small changes in metabolism could be detected, indicating that, despite signs of imminent clinical incarceration, the energy supply to the brain was substantial. 1H-MRS of the 3rd patient showed massive lactate concentration, and 31P-MRS revealed the total absence of high-energy phosphorous compounds leaving only one single peak of inorganic phosphate, indicating irreversible brain death.

[Preoperative EEG in medically intractable epilepsy]. / Praeoperativt eeg ved medicinsk intraktabel epilepsi.

The aim of the preoperative neurophysiological investigations is to identify the primary epileptogenic focus and its relation to functional cortical areas. The investigations include interictal and ictal extracranial (scalp) electroencephalography (EEG) and invasive methods (depth, subdural, foramen ovale electrodes and peroperative electrocorticography). If an epileptic focus is located in the anterior part of the temporal lobe by the use of scalp EEG, this is normally regarded as sufficient for an anterior lobectomy. However, because of poor spatial resolution by scalp EEG, it is difficult to separate mesial from lateral foci, identify the exact extent of posterior temporal or extra-temporal foci, identify the primary focus in patients with bilateral abnormalities and identify cases with minor scalp EEG-changes. As invasive EEG shows higher spatial resolution and gives an opportunity to evaluate functional areas, invasive EEG has significant advantages in these patients. Use of invasive EEG bears a slightly increased risk and discomfort to the patient, but is necessary in the presurgical evaluation of some patients suffering from medically intractable epilepsy.

Diagnostic imaging in fracture of lumbar vertebral ring apophyses.

The findings at plain radiography, myelography, CT, and MR imaging in 3 cases of fracture of the lumbar vertebral ring apophysis are presented. Familiarity with this entity is important in evaluating low back pain in children and young adults. Conventional radiographs and/or MR imaging may suggest ring apophysis fracture; CT will confirm and classify the diagnosis.

Fracture of the lumbar vertebral ring apophysis imitating disc herniation.

Three cases of fracture of the lumbar ring apophysis representing type I, II, and III are described in detail and the natural history of these fractures is discussed. The symptoms of apophyseal fractures are usually low back pain, sciatica, tension signs, and neurological deficits, thus imitating the symptoms of lumbar disc herniation. Plain radiography and magnetic resonance are often inconclusive and computed tomography is essential for the true diagnosis. An explanation of the different types of fractures, based on the osteogenesis of the human vertebra, is proposed. Recognition of these fractures is essential for proper planing of surgery, and apophyseal ring fractures must be suspected when children and young adults show signs of lumbar disc herniation.

Regional cerebral blood flow in pigs estimated by microspheres.

Regional cerebral blood flow in anaesthetized pigs is determined with the microsphere method. Five regions of cortical grey matter and three white subcortical areas in each hemisphere are examined together with anatomically classic structures. The validity of the biopsies was confirmed by freeze drying of the tissue. Three flow measurements in a group of six animals showed large interindividual variations whereas regions with the same structure in the particular animal showed a high degree of uniformity. Symmetrical regions in the two hemispheres were similar with a coefficient of variation between sides of less than 5%. The coefficient of variation of the particular flow measurements were 15%. The different brain structures have four discernible flow levels. White subcortical matter has three different flow values and forms together with medulla oblongata and hippocampus the low flow area. Flow in grey cortical matter is of the same magnitude as in unanaesthetized animals and constitutes together with thalamus, mesencephalon, pons and cerebellar hemispheres the intermediate flow level. The high flow areas are nucleus caudatus and lentiformis together with the cerebellar vermis. The choroid plexus, pituitary gland and pineal gland all have very high flow values and seem, in contrast to the rest of the brain, insensitive to the CO2-tension in arterial blood and global cerebral metabolism. Microsphere estimation of regional blood flow seems to be an appropriate technique for evaluating regional cerebral blood with a high degree of spatial resolution in repeated flow measurements.