A report on neurosurgical workforce in the countries of the EU and associated states. Task Force "Workforce Planning", UEMS Section of Neurosurgery.

AIM: Aim of this report was to present recently collected data on neurosurgical workforce in the countries of the EU and associated states. METHODS: Data were obtained from 27 countries by means of a questionnaire developed by members of a working group of the UEMS Section of Neurosurgery (UEMS = Union Europénne des Médecins Spécialistes; European Union of Medical Specialists). Most data originate from 2005/2006. Results were discussed, amended, and approved by the countries' delegates of the UEMS Section of Neurosurgery. RESULTS: The number of Neurosurgeons (NS) per population varies considerably among these countries. The mean is one neurosurgeon per 99,152 population. The number of neurosurgical operations per population per year varies similarly with a mean of 1,642 operations per million population/year. Countries with fewer neurosurgeons per population tend to have less neurosurgical operations per population and vice versa. The average number of operations performed by one neurosurgeon per year (annual caseload) is between 56 and 300 with a mean of 154. A numerus clausus for neurosurgical training is reported in 13 countries, another 13 countries have no numerus clausus. The annual intake of new trainees is between 2.4 and 10.3% of the number of accredited neurosurgeons with a mean of approx. 5.2%. The average yearly loss rate due to retirement, sickness, other activities, etc. can only be estimated and lies in the range between 2.3 and 3.36% of the number of accredited NS. According to the figures provided by the countries, the total number of accredited NS in 2005/2006 was approx. 6,280 for a population of about 504.7 millions. These countries had an annual intake of approx. 332 new trainees.

Chordoid glioma of the third ventricle: confirmatory report of a new entity.

The term "chordoid glioma" was recently introduced to denote a circumscribed, apparently low-grade neoplasm arising in or preferentially involving the third ventricle of middle-aged women. We report biopsy and postmortem findings in a 60-year-old woman with symptoms of forgetfulness, headache, and lethargy. Neuroimaging showed a contrast-enhancing third ventricular mass with obstructive hydrocephalus. The tumor was subtotally resected. Microscopically, it consisted of clusters and strands of epithelioid cells in a mucoid matrix. Its margins were remarkably discrete and showed little tendency to infiltrate surrounding brain parenchyma. The majority of neoplastic cells were glial fibrillary acidic protein (GFAP) and vimentin positive, whereas S100 protein labeled only individual cells. Stains for epithelial membrane antigen (EMA) and cytokeratin were nonreactive. There was no evidence of neuroendocrine differentiation or expression of estrogen and progesteron receptors. Lymphoplasmacellular infiltrates were noted throughout the lesion and at the tumor-brain interface. The MIB-1 labeling index averaged 1.5%. At present, chordoid glioma is considered a glial neoplasm of uncertain histogenesis with distinct clinicopathologic features.

Influence of nitrovasodilators and cyclooxygenase inhibitors on cerebral vasoreactivity in conscious rabbits.

Since the nitric oxide (NO) and cyclooxygenase pathways have been suggested to have important roles in most vasodilations, our aim was to study the influence of cyclooxygenase inhibitors and nitrovasodilators on cerebrovascular reserve capacity. Corticocerebral blood flow was measured by hydrogen polarography during hypercapnia and acetazolamide stimuli in conscious rabbits. The measurements were repeated in the presence of N(omega)-nitro-L-arginine methyl ester (L-NAME) and indomethacin as nitric oxide synthase (NOS) and cyclooxygenase inhibitors. The effects of nitroglycerin and isosorbide-5-nitrate were also tested. L-NAME completely, while indomethacin markedly inhibited the hypercapnic corticocerebral blood flow response. Nitroglycerin and isosorbide-5-nitrate significantly attenuated hypercapnia elicited corticocerebral blood flow increase. The different treatments reduced only moderately the acetazolamide-induced corticocerebral blood flow response. These results lend support to the hypothesis that antithrombotic and antiinflammatory medication (cyclooxygenase inhibitors) and nitrovasodilator treatments could interfere with the measurement of cerebrovascular reactivity resulting in underestimation of the cerebrovascular reserve capacity in patients taking these drugs.

The effect of skull and dura on brain volume regulation after hypo- and hyperosmolar fluid treatment.

This study was performed to determine the response of brain water and electrolytes to acute hypo-osmolality and hyperosmolality in animals with intact skulls and dura, in comparison with those subjected to extensive bilateral or unilateral craniectomy and opening of the dura. In rats, 4 to 5 weeks after extensive unilateral or bilateral craniectomy and opening of the dura, a 50-mOsm/kg decrease in plasma osmolality was produced by systemic administration of distilled water ("water intoxication"), or a 28-mOsm/kg increase in plasma osmolality was produced by systemic administration of either 1 M NaCl or 1 M mannitol in 0.34 M NaCl. Tissue water, Na. and K contents were determined after 120 minutes. Tissue water accumulation or water loss was proportional to the decrease or increase in plasma osmolality. The tissue water accumulation after "water intoxication," however, was less (40% of the predicted value) than that predicted for ideal osmotic behavior. The brain tissue was also found to shrink less than predicted on the basis of ideal osmotic behavior (40% of the predicted value after mannitol treatment, and 60% after NaCl administration). This nonideal osmotic response of the brain tissue is consistent with the finding in other studies and indicated a significant degree of volume regulation. Water and electrolyte changes did not differ between animals operated on and those not operated on, a fact which demonstrates that there are no effects of extensive skull and dura defects on tissue volume regulation under hypo- and hyperosmolar conditions encountered under clinical circumstances.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased concentration of atrial natriuretic factor in the cerebrospinal fluid of patients with aneurysmal subarachnoid hemorrhage and raised intracranial pressure.

Plasma and cerebrospinal fluid (CSF) atrial natriuretic factors/peptides (ANFs/ANPs) were measured in 26 patients with normal or raised intracranial pressure (ICP) by means of an instant radioreceptor assay. All 26 patients were suffering from aneurysmal subarachnoid hemorrhage (SAH), and 11 had also developed raised ICP (ICP greater than 20 mm Hg). In SAH patients with normal ICP, the plasma levels of ANF were 20 to 200 pg/ml (mean +/- SE, 89 +/- 68 pg/ml); in the 11 SAH patients with raised ICP, however, ANF levels were 14 to 262 pg/ml (mean 114 +/- 79 pg/ml). The difference was not statistically significant. The ANF/ANP plasma levels in 6 healthy volunteers were 15 to 167 pg/ml (mean 77 +/- 32 pg/ml). Although the ANF/ANP concentration in the CSF of patients with normal ICP did not reach the lower limit of detectability (i.e., 4 pg/ml) in any case, in those with elevated ICP it was 14 to 120 pg/ml (mean 49 +/- 37 pg/ml). This difference was statistically highly significant. The results of this preliminary study suggest that the ANF/ANP concentration in human CSF is 1 to 2 orders lower than that in the plasma and that there is no significant correlation between ANF/ANP levels in the CSF and the plasma. After SAH in patients with raised ICP, there was an accompanying increase in the ANF/ANP concentration in the CSF, but the ANF/ANP concentration in the plasma was not changed significantly. Accordingly, a central ANF/ANP release might be hypothesized to play a causative or adaptive role in the neuroendocrine regulation of ICP dynamics, although this may simply be an epiphenomenon.

Regulation of brain water and electrolyte contents: the possible involvement of central atrial natriuretic factor.

The intraventricular administration of 0.2 or 2 micrograms of synthetic rat atrial natriuretic factor (syn rANF), sequence 101-126 of the precursor, prevented the water accumulation elicited in rat brain by a systemic hypoosmolar fluid load and led to a statistically significant sodium loss from the nervous tissue, while the potassium content remained unaltered. Similar syn rANF administration to rats not treated with a hypoosmolar fluid load caused no significant change in the water, potassium, and sodium content of the hemispheres. In this experiment, a primary systemic action of centrally administered syn rANF with ensuing secondary changes in brain ion and water homeostasis seems unlikely, as the serum osmolality and sodium and potassium concentrations remained unaltered. Thus, a central influence of the intraventricularly administered hormone upon the water and ion balances of the nervous tissue can be hypothesized. The significant loss of sodium may reflect the primary role of volume regulation of the nervous tissue, i.e., the loss of extracellular osmols such as Na+ in response to a hypoosmolar environment. These data lend further support to the concept that a central neuroendocrine system regulates brain ion and volume homeostasis. The possible role of ANF in the management of brain edema should be considered.

Effects of intraventricularly injected isoosmolar glycerol on brain water and electrolytes in the rat.

The infusion of isoosmolar glycerol (0.35 mol/dm-3) into the ventricles of laboratory rats for 120 minutes led to an increase in the serum osmolality by 11 mosm/kg and to hypernatremia. The brain water content of the cerebral hemispheres decreased by 0.9% (P less than 0.05). A corresponding intraventricular infusion of saline or d-glucose did not cause significant changes in these parameters. These findings support the view that glycerol, even in a dose incapable of creating a major osmotic gradient between plasma and brain, could have a beneficial effect in the control of intracranial volume-pressure perturbations. It is hypothesized that, besides acting as an osmotic dehydrating agent in certain concentrations, glycerol influences the central neuroendocrine system responsible for brain ion and volume homeostasis. By its presumed reduction of central and peripheral vasopressin release through lowering the cerebrospinal fluid sodium concentration, it may help in decreasing the brain water content.

Significance of the rate of systemic change in blood pressure on the short-term autoregulatory response in normotensive and spontaneously hypertensive rats.

Cerebral autoregulation, the physiological regulatory mechanism that maintains a constant cerebral blood flow (CBF) over wide ranges of arterial blood pressure, was investigated in normotensive and spontaneously hypertensive rats by means of laser-Doppler flowmetry. Systemic arterial hypertension was produced at rates ranging from 0.02 mm Hg/second to 11 mm Hg/second by constant infusion of epinephrine and norepinephrine. Systemic arterial hypotension was produced at rates ranging from -0.03 mm Hg/second to -12 mm Hg/second, either by bleeding the animals into a reservoir or by compressing the abdomen. In those cases with a low rate of change in systemic arterial blood pressure (SABP), the measurements lasted for 5 +/- 2 minutes, and in those with a high rate of change in SABP, measurements lasted for 40 +/- 30 seconds. The purpose was to record the time of onset and course of autoregulation in the basal ganglia in response to slow or rapid changes in SABP. CBF in the basal gray matter remained at baseline values (i.e., autoregulation was functioning) if the rate of increase of SABP did not exceed a critical value (0.10 mm Hg/second in the normotensive rats; 0.35 mm Hg/second in the spontaneously hypertensive rats). When hypertension was produced at faster rates, CBF followed arterial blood pressure passively, and no autoregulatory response was observed for 2 +/- 1 minutes. Hypotension did not change the baseline CBF when it was not produced at a rate faster than -0.4 mm Hg/second in normotensive rats and -0.15 mm Hg/second in spontaneously hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurements of regional cerebral blood flow and blood flow velocity in experimental intracranial hypertension: infusion via the cisterna magna in rabbits.

Cerebral blood flow velocity, as measured in the intracranial segment of the internal carotid artery by transcranial Doppler sonography via the transorbital route, and regional cerebral blood flow and volume in corresponding cortical areas, as measured by the hydrogen clearance technique, were recorded for eight New Zealand White rabbits subjected to infusion via the cisterna magna to elevate intracranial pressure. In the lower range of autoregulation, that is, at perfusion pressures between 80 and 40 mm Hg and even lower, the changes in cerebral blood flow velocity and cerebral blood flow showed a strong correlation (0.86) under conditions of standard pCO2 (PaCO2 = 35 +/- 2 mm Hg). Autoregulation was exhausted at 40 mm Hg, and the cerebrovascular resistance was minimal. Below this perfusion pressure, the cerebral blood flow and volume dropped sharply, whereas the cerebrovascular resistance gradually increased, indicating that, despite the maximally dilated resistance vessels, intracranial hypertension causes vascular resistance to increase, possibly via blocking of the venous outflow. Our results confirmed that noninvasive and easily (even at bedside) applicable measurements of changes in cerebral blood flow velocity could be a substitute for the cumbersome and expensive isotope measurements of cerebral blood flow in patients with intracranial hypertension.

Evaluation of cerebral vasoreactivity by SPECT and transcranial Doppler sonography using the acetazolamide test.

rCBF SPECT with 99mTc-HMPAO was performed prospectively in 29 patients (3 controls and 26 stroke patients) as well as TCD studies in 20 patients (3 controls and 17 stroke patients) before and after 1 g i.v. acetazolamide. The sensitivity of rCBF SPECT increased from 62% to 77% after acetazolamide provocation in stroke patients. In patients with a reversible neurological deficit, the sensitivity under resting conditions was 50% which increased to 71%, while in cases with a permanent deficit it increased from 75% to 83%. In the evaluation of the cerebrovascular reserve capacity the results of rCBF SPECT and TCD coincided in 91% of the hemispheres. The correlation was statistically significant.

Intraventricular hemorrhage as a false localizing sign of a thoracolumbar arteriovenous malformation: case report.

BACKGROUND: Spinal arteriovenous malformation (SAVM) is a relatively rare disease characterized by a high incidence of intramedullary and subarachnoid haemorrhage. When the hemorrhage is profuse and the SAVM is in the cervical region the symptoms (disturbance of consciousness, papilledema, cranial nerve palsies, and convulsions) may be so severe and rapid in their onset that they may be mistaken for intracranial hemorrhage. We report here on a patient with a SAVM at T10-12, which bled intracranially, mainly intraventricularly, and resulted first in respiratory arrest and unconsciousness. CASE DESCRIPTION: The patient had been well until he was 28 years old when, during intercourse, he suffered a terrible headache and suddenly lost consciousness, with a transient respiratory arrest. He was also noted to have right hemiparesis. A computed tomography scan demonstrated intraventricular hemorrhage. After a 24-hour period of artificial ventilation the patient regained consciousness and the right arm paresis completely recovered, but a gradual worsening of the motor function of the left leg developed. Digital subtraction angiography did not demonstrate any intracranial source of bleeding, whereas spinal angiography revealed a SAVM located at the medullary cone, which was totally removed by surgery. CONCLUSION: The case reported here raises several important issues. First, the advisability of spinal magnetic resonance imaging in the investigation of intraventricular (and subarachnoid) hemorrhage in patients with no demonstrable intracranial source. Secondly, the benefits of early diagnosis and reestablishment of the spinal cord circulation before the onset of thrombosis and the progressive phase of myelopathy. Finally, the necessity of complete obliteration and treatment of SAVMs even in patients with fixed neurologic deficits, because rebleeding of lower thoracic or lumbar SAVMs can lead to impairment at a higher level with severe or lethal consequences.

Fluorescein angiography in the surgical treatment of cerebral ischemic lesions.

The present paper summarizes our experiences with intraoperative fluorescein angiography in 50 external carotid artery-internal carotid artery bypass operations. This technique has provided precise localization of the ischemic lesion and aided in selecting the sites and direction of the anastomoses to be performed, as well as in checking the patency of the anastomoses and the area supplied by them. A comparison of X-ray angiography with fluorescein angiography indicates the reliability of the latter in the estimation of the area supplied by the anastomosis.

Stenoses of the distal segments of the internal carotid artery.

In 31 of 51 patients with stenosis of the distal segments of the internal carotid artery, the first symptom was a transient ischemic attack. In spite of the high incidence of angiographically proved emboli, 46 patients remained in good neurological condition. Aspirin was given to all patients. In 4 patients a total occlusion developed, causing severe neurological deficit. This indicates that the danger of occlusion is significantly higher than that of embolization. External carotid-internal carotid artery bypass was carried out in 23 patients; occlusion developed during the postoperative observation period in 4 patients without any neurological consequences. It can be concluded that an EC/IC bypass operation is the method of choice in treating patients with severe distal stenosis or recent mural thrombi.

[Hydrocephalus following subarachnoid hemorrhage]. / L'hydrocéphalie après hémorragie sous-arachnoïdienne.

Post-hemorrhagic hydrocephalus was studied in two homogeneous series including 410 patients, 320 of whom had ruptured intracranial aneurysms. Ventricular dilatation was more frequently observed in the patients with subarachnoid hemorrhage from ruptured aneurysm (44%) than in those in whom no vascular malformation was detected by the four vessel angiography (21%). Moreover, hydrocephalus was over twice as frequent in high grading (76-64%) than in low grade patients (31-35%). Ventricular dilatation was revealed in 58-52% of A.Co.A., in 39-30% of C.I.A. and in 20-21% of M.C.A. Altogether 51 patients underwent continuous ventricular drainage (EVD): 54% improved significantly, but fatal recurrent hemorrhage took place on drainage in half of them. On these grounds, it would appear that EVD may be indicated only in grade IV and, occasionally, in Grade III patients on condition that early radical surgery is carried out as soon as significant improvement is attained, without waiting for an entirely satisfactory grading. In this way, devastating hemorrhages on drainage could be prevented in the last patients of our series. Chronic disturbances of CSF dynamics calling for permanent shunting proved exceedingly rare in our patients.

[The effect of carotid endarterectomy on the reserve capacity of cerebral blood flow velocity]. / Carotis endarterectomia hatása az agyi rezisztenciaerek rezervkapacitására.

Cerebral blood flow velocity was measured by transcranial Doppler sonography at rest and during cerebral vasodilatation evoked with acetazolamide in 14 patients before and after carotid endarterectomy. Before surgery the vasoreactivity in the affected middle cerebral artery territories was reduced and abnormal (asymptomatic side: 35.9 +/- 25.6% [mean +/- SD; n = 14]; symptomatic side: 25.6 +/- 10.7%), but the difference between the two hemispheres was not significant however, vasoreactivity was normalized 5 days after surgery (asymptomatic side: 46.9 +/- 22.3% symptomatic side: 58.9 +/- 23%) (p < 0.001). The increase in cerebral reserve capacity and changes in Gosling's index of pulsatility correlated significantly in both hemispheres (p < 0.02). This findings indicate an improved perfusion reserve on the fifth day following carotid endarterectomy in patients with an internal carotid artery diameter reduction of at least 70%.

[Clinical significance of lumbosacral transitional vertebrae (Bertolotti syndrome)]. / A lumbosacralis átmeneti csigolyák kóroki szerepéröl (Bertolotti syndroma).

500 lumbosacral plain x-ray injured patients and 1000 myelography of patients suffering from low back pain and nerve root sign were reviewed to evaluate the rate of transitional lumbosacral vertebra. This anomaly appeared in 4.6% in the normal population. The rate of the transitional vertebra in patients with nerve root syndrome was double (8.4%) whereas that with lumbar disc herniation four time as many as in the normal population. The data demonstrate that the asymmetrical anomalies have more clinical significance. The authors consider, that the role of the transitional vertebra is twofold: it can be consider primary in low back and sciatic pain, but in the formation of lumbar disc herniation is secondary. They find the analysis of the lumbosacral plain x-ray is necessary even in cases with CT and MRI.

[Management of trigeminal neuralgia by microvascular decompression]. / Trigeminus neuralgia kezelése microvascularis dekompresszióval.

The experience with a series of 28 posterior fossa exploration and microvascular decompression for trigeminal neuralgia is presented. All the patients were treated with carbamazepine previously and some of them were operated on by destructive methods. The diagnostic work-up consisted of an accurate history, CT or MRI in all cases, and recently (in 17 cases) the vascular compression of the trigeminal nerve was demonstrated directly by MR angiography in the plane of the trigeminal nerve. Microvascular decompression was performed through a suboccipital retromastoid craniotomy. At the operations 21 arterial, 4 venous, 2 combined (arterial + venous) and 1 arachnoid band compression were found. The mean follow up was 30 months. Immediate pain relief was achieved in all cases but one, and there were two recurrences 6 and 12 months later (both of them were venous compression), which have been controllable medically since then. There were 3 permanent hypaesthesia of the face (one of them loss of corneal reflex), 2 hypacusis, 1 cerebrospinal fluid leakage and 1 cerebellar edema as complications. Microvascular decompression is a safe and effective treatment for trigeminal neuralgia and advised if the medical treatment is failed, the patient suitable for general anaesthesia, and there is the evidence of vascular compression of trigeminal nerve on MR angiography.

[Symptomatic glial cysts of the pineal gland: report of two cases and review of the literature]. / A corpus pineale symptomaticus glialis cystái: két eset ismertetése és irodalmi áttekintés.

Referring to two individual cases, the authors review clinical, radiological and histological features of benign glial cysts of the pineal gland. Both patients were young females with aggravating headaches and with convulsions in one case. Symptoms were referable to a space-occupying cystic mass of the pineal gland. On histology, both lesions proved to be non neoplastic cysts without an epithelial lining. Their histogenesis and low growth potential were reinforced by immunohistochemical analysis of pineal antigens and proliferation markers. Glial cysts of the pineal gland are not infrequent, but symptomatic occurrences are exceptional. Most glial cysts are of dysontogenic or degenerative origin. Sometimes, however, the role of hormonal influences or paraneoplastic factors must be considered. Symptoms caused by glial cysts of the pineal gland are non-specific and radiologic imaging technics may contribute little to etiologic diagnosis. Pineal cysts are curable by surgical resection or stereotactic decompression. Whatever the diagnostic approach, emphasis must be laid on the histologic examination in order to avoid unnecessarily aggressive treatment.

[Cavernous angioma of the central nervous system]. / A központi idegrendszer cavernosus angiomáiról.

The developmental and morphological characteristics, clinical course, diagnostic and therapeutic possibilities of cavernous angiomas of the central nervous system are summarized on the basis of the literature. The clinical courses of 27 patients with cavernous angiomas are presented. The surgical treatment of cavernous angiomas has had a good outcome when the indications and microsurgical principles were adhered to. Special attention should be paid to cavernous angiomas located near or inside the ventricles because of the danger they may cause.

[Results of surgical treatment in hemifacial spasm--the role of MR-angiography in detecting microvascular compression]. / Hemifacialis spasmus mútéti kezelésének eredménye MR-angiográfiával kimutatott microvascularis kompresszió esetén.

The authors evaluated the follow-up results of microvascular decompression (sec. Janetta) in 8 patients with hemifacial spasm (HFS). Indication was based on there dimensional time of flight magnetic resonance angiography with 0.5T Elscint Gyrex V Dix equipment. Contrast material was administered in every case and maximum intensity projection and thin slice reconstruction were performed in three standard directions. Vascular contact with the facial nerve in the entry zone was identified on the symptomatic side in 10 patients. No contact was detected in 2 cases. Microvascular decompression was performed in 8 cases. The surgical and neuroradiological findings were identical in every cases. Five patients were completely free of HFS immediately after surgery, and another 2 patients became free of HFS during the next few weeks. Only 1 patient had uncured symptoms. In conclusion, the authors suggest that microvascular decompression of the facial nerve may evolve as the method of choice if vascular contact is proved by 3D TOF MRA.