Servet Inci

Intracranial aneurysms and arterial hypertension: a review and hypothesis.

BACKGROUND Intracranial aneurysms and systemic arterial hypertension coexist in a high percentage of patients. The relationship between intracranial aneurysms and hypertension is poorly defined. METHODS Therefore, we reviewed the role of hypertension in the pathogenesis of saccular aneurysms as previously reported in clinical, experimental, and autopsy studies. RESULTS Among 24 relevant clinical and/or autopsy studies, the mean incidence of pre-existing hypertension was 43.5% in aneurysm patients compared to 24.4% in the normal population. Although definitive evidence is lacking, data from multiple types of investigations indicate that systemic arterial hypertension creates a greater risk for the development of intracranial aneurysms than previously believed. The underlying pathophysiological mechanism(s) are also poorly defined. CONCLUSIONS We propose a unifying hypothesis: Endothelial injury, occlusion of the vasa vasorum, and disruption of the synthesis of collagen and elastin are likely the most important factors in initiating the development of aneurysms. Chronic hypertension potentially affects all of these factors. Consequently, chronic hypertension may cause intimal thickening, necrosis of the tunica media, changes in the compositional matrix, and degeneration of the internal elastic lamina to develop in the arterial wall. These structural changes could cause a focal weakening in the arterial wall with resultant bulging. This theory accounts for the high incidence of intracranial aneurysms in the absence of any known associated hereditary or connective-tissue disease. Nor does it exclude the possibility of other etiological factors. From the perspective of prevention, however, it offers clear opportunities for prophylaxis.

Time-Level Relationship for Lipid Peroxidation and the Protective Effect of α-Tocopherol in Experimental Mild and Severe Brain Injury

OBJECTIVE Oxygen free radical-mediated lipid peroxidation has been proposed to be one of the major mechanisms of secondary damage in traumatic brain injury. The first purpose of this study was to establish the time-level relationship for lipid peroxidation in injured brain tissue. The second purpose was to examine the protective effect of alpha-tocopherol against lipid peroxidation. METHODS For this study, 65 guinea pigs in five groups were studied. Five of the animals were identified as a control group, and the remaining 60 animals were divided equally into four groups (Groups A, B, C, and D). Mild injury (200 g x cm) (Groups A and C) and severe injury (1000 g x cm) (Groups B and D) were produced by the method of Feeney et al. Alpha-tocopherol (100 mg/kg) was administered intraperitoneally before brain injury in Groups C and D. Five animals from each group were killed immediately after trauma, five after 1 hour, and the remaining five animals after 36 hours. Lipid peroxidation in traumatized brain tissues was assessed using the thiobarbituric acid method. RESULTS In all groups with traumatic brain injuries, levels of malondialdehyde, a lipid peroxidation product, were higher than in the control group. The amount of lipid peroxidation was increased by the severity of the trauma. Alpha-tocopherol significantly suppressed the rise in lipid peroxide levels in traumatized brain tissues. CONCLUSION This study demonstrates that lipid peroxidation is increased by the severity of trauma and that alpha-tocopherol has a protective effect against oxygen free radical-mediated lipid peroxidation in mild and severe brain injury.

Aneurysms of the distal anterior cerebral artery: Report of 14 cases and a review of the literature

BACKGROUND Distal anterior cerebral artery aneurysms are rare and compose about 4.5% of all intracranial aneurysms. They generally arise at the bifurcation of the pericallosal and callosomarginal arteries. Their surgical approach is different from those of other anterior circulation aneurysms. These aneurysms present some special difficulties for neurosurgeons, including narrow exposure in the interhemispheric fissure, dense adhesions between the cingulate gyri, difficulty in controlling the parent artery, and the association of multiple aneurysms and vascular anomalies. METHODS Between January 1975 and May 1996, 14 cases of saccular aneurysms of the distal anterior cerebral artery were operated at the University of Hacettepe. The clinical presentations, neuroradiological findings, and operative approaches of these aneurysms were analyzed. In addition, the clinical series and isolated case reports in the English literature were also extensively reviewed. RESULTS The incidence of the aneurysms in this location was 2.8% of a total of 494 surgically treated cases in our center. Of 14 patients, eight were women and six were men. Multiple aneurysms were found in five patients (35%). All patients were operated via the interhemispheric route. Thirteen patients had good outcome and one patient died. CONCLUSIONS We believe that all difficulties related to distal anterior cerebral artery aneurysms can be minimized with sufficient knowledge of microsurgery and surgical anatomy, using microtechniques and experience.

Treatment of a Superior Sagittal Sinus Dural Arteriovenous Fistula with Onyx: Technical Case Report

OBJECTIVE: The endovascular treatment of a complex superior sagittal sinus dural arteriovenous fistula with ethylene vinyl alcohol copolymer (Onyx) in one session is described. CLINICAL PRESENTATION: A 54-year-old man presented with dizziness and a bruit. A cerebral angiogram demonstrated a superior sagittal sinus dural arteriovenous fistula with a patent superior sagittal sinus that was supplied via multiple branches of the external carotid arteries bilaterally and the left anterior and middle cerebral arteries. Drainage was mainly through the superior sagittal sinus and, only in part, retrogradely through the cortical veins. A decision was made to proceed with endovascular treatment followed by surgery. INTERVENTION: Transarterial injection of one pedicle of middle meningeal artery on both sides with Onyx resulted in complete obliteration of the dural supply and some of the pial supply to the malformation without complications. The superior sagittal sinus remained patent. Based on this result, surgical treatment was cancelled. The residual pial supply had disappeared by the 10-month angiographic follow-up examination and the patient remained neurologically intact and without symptoms. CONCLUSION: Definitive treatment may be attained with Onyx in dural arteriovenous fistulas. The potential of Onyx for use as a permanent embolic agent in dural arteriovenous fistulae needs to be investigated.

Pulmonary embolism in neurosurgical patients.

BACKGROUND Pulmonary embolism continues to be a frequent cause of morbidity and mortality in neurosurgical practice. This study was designed to investigate the presence of signs and/or symptoms helpful for an early diagnosis of pulmonary embolism and to evaluate the safety of heparin treatment in neurosurgical patients. METHOD We retrospectively reviewed 37 patients with pulmonary embolism among 6081 operated patients within the past 8 years at the Department of Neurosurgery, University of Hacettepe. RESULTS The overall incidence of pulmonary embolism was 0.42% and the mortality rate was 59.4%. The patients with cerebrovascular lesions had a significantly higher risk of pulmonary embolism compared with other neurosurgical pathologies. All patients were treated with heparin and subsequent oral warfarin therapy. None had intracranial or intraspinal bleeding while receiving anticoagulant therapy. CONCLUSIONS This study demonstrates that pulmonary embolism has a high mortality rate and heparin therapy can be used safely and without fear of intracranial or intraspinal bleeding.

Solitary Dural Plasmacytoma

Solitary intracranial plasmacytomas are exceedingly rare. Before this case report, only 14 cases of solitary dural and 4 cases of intracerebral plasmacytomas had been reported in the literature. We present a case of solitary plasmacytoma originating from the right frontal dura mater in a 52-year-old man; we also review the literature on the previous cases. To our knowledge, our patient is the first patient with a solitary dural plasmacytoma to be examined with magnetic resonance imaging.

Nimodipine attenuates lipid peroxidation during the acute phase of head trauma in rats

Abstract Oxygen free radical-mediated lipid peroxidation is one of the major mechanisms of secondary damage in traumatic brain injury. We assessed the effects of nimodipine on lipid peroxidation 1 h after head trauma in rats. Nimodipine (1.5 µg/kg IV bolus injection) was given immediately after head trauma by either the carotid artery or the jugular vein. Placebo treated rats received saline by the same routes. Control rats received head trauma only. Sham-operated rats were the group without head trauma. Malondialdehyde (MDA), which is the end product of lipid peroxidation, was measured as an indicator of oxygen free radical formation in the brain tissue. The mean values for MDA in sham operated rats were 92.4±4.9 nanomoles/gram wet weight (nmol/gww) of brain tissue. In the control group, MDA content of the brain tissue was 120.8±9.4 nmol/gww. In placebo treated rats, the results were similar. In the groups receiving nimodipine via carotid artery or jugular vein, the mean values were 101.1±6.9 and 106.5±6.0 nmol/gww, respectively. These results indicate that nimodipine caused a significant decrease in lipid peroxidation when given in the acute phase of head trauma in rats. This occurred regardless of the route of injection.

Aneurysmal bone cyst of the frontal bone

Aneurysmal bone cyst rarely affects the skull. We report two cases of aneurysmal bone cyst of the frontal bone. One of the cases is associated with pregnancy. The association of pregnancy with aneurysmal bone cyst and enlargement of the aneurysmal bone cyst during the pregnancy have been discussed.

Horner's syndrome due to jugular venous ectasia

Horners syndrome may be caused by a lesion anywhere along the three-neuron pathway from the hypothalamus to the eye. This syndrome has been reported secondary to numerous causes to date. In this paper, we describe an extremely rare case of Horners syndrome due to jugular venous extasia demonstrated by computed tomography and intravenous digital subtraction angiography.

Lipid peroxidation in cerebral tumors

BACKGROUND Serum and tissue concentrations of tumor markers or some metabolites are considered to be helpful in diagnosis and follow-up of the central nervous system (CNS) disease. However, markers currently available are not sufficiently sensitive and specific to be used as actual diagnostic tools. Differentiation between the malignant and benign lesions of the CNS is very important, both for determining the optimum therapeutic approach and to predict morbidity and mortality of the disease. Accurate diagnosis of a malignant disease is mostly performed through a surgical resection and histopathologic evaluation. Free oxygen radicals (FOR) are thought to take part in oncogenesis and cellular differentiation. We explored whether FORs can be used as diagnostic tumor markers. METHODS We investigated the concentration of malondialdehyde (MDA) in the serum and tumor tissue of patients with glial tumor. We have studied 30 patients with malign glial tumor (grades III and IV astrocytoma), 30 patients with low grade glial tumor, 28 healthy individuals, and 10 patients with nontumorous lesions (lobectomy for epilepsy). RESULTS Patients with CNS tumors showed higher serum MDA concentration compared to control groups (epilepsy patients and healthy subjects). These patients had a higher tumor tissue MDA concentration compared to lobectomy tissue from epilepsy patients. Serum and tissue MDA concentrations were also higher in the malignant glial tumor group compared to the low grade glial tumor group. CONCLUSIONS Although not specific, tissue and serum concentrations of FORs can be used as a marker to detect the presence and grade of CNS tumors. Further studies are needed to determine the optimum cutoff value for use of serum and tissue MDA concentrations in brain tumors.