O E Ozcan

Hacettepe University, Ankara, Ankara, Turkey

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Publications (81)113.16 Total impact

  • I M Ziyal · B Bilginer · Ö. Çelik · O E Ozcan · T Ozgen
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    ABSTRACT: Almost all meningiomas presenting with intracranial hemorrhage in the literature were admitted with symptoms relating to the hemorrhage and there were no prehemorrhage scans which demonstrated the actual size and apperance of the meningioma. This is a very rare report of a case with a tentorial meningioma documented with pre- and posthemorrhage scans.
    No preview · Article · Jan 2007 · Acta Neurochirurgica
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    ABSTRACT: Diagnosis of oligodendroglioma from other clear cell neoplasms of central nervous system (CNS) is still challenging despite advances in neuroradiology and molecular diagnostic tools. Herein, we present a 44-year-old male patient who had a diagnosis of right parietal oligodendroglioma grade II in 1994 which recurred in 2002. He presented with intratumoral hemorrhage and he underwent radical resection of tumor in 2003. Histopathological examination of the recurrent tumor showed anaplastic progression with confusing immunohistochemical (IHC) results; the tumor was positive for NeuN and synaptophysin staining. The question arisen was whether the recurrent tumor was an oligodendroglioma with neuronal differentiation or an extraventricular neurocytoma initially misdiagnosed as oligodendroglioma. Repeated IHC staining showed negative results for NeuN and synaptophysin. Chromosomal analysis revealed 1p/19q deletion, which led to the diagnosis ofanaplastic oligodendroglioma grade III. Accurate diagnosis of oligodendroglioma is crucial due to recent advances and promises in its treatment. Current diagnostic methods of oligodendroglial tumors are discussed in context of differentiating oligodendrogliomas from other clear cell neoplasms of CNS, especially from extraventricular neurocytomas.
    No preview · Article · Sep 2005 · Clinical neuropathology
  • G Bozkurt · I M Ziyal · A Akbay · D Dal · B Can · O E Ozcan
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    ABSTRACT: 'Silk cocoon' appearance on spinal angiography is pathognomonic to differentiate paragangliomas from several vascular tumors and malformations of cauda-filar region.
    No preview · Article · Feb 2005 · Acta Neurochirurgica
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    IM Ziyal · B Bilginer · OE Ozcan · R Basar · LN Sekhar · T Ozgen
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    ABSTRACT: In this study, the mobilization of all cranial nerves with drilling of several bony structure,cutting of ligaments, folds and dural attachments were performed via different skull baseapproaches.Twenty cadaveric head specimens filled with microfil were dissected bilaterally. On 5 dryskulls, important bony structures were also studied.We observed that the mobilization of the nerves II, III, VI, VIII, and XII were not easycomparing to other cranial nerves. The subfrontal parenchymal tissue should be removedand the olfactory nerve should be dissected for mobilization of the first cranial nerve. Themobilization of the nerves IV, V, VII, IX, and XI were dramatically remarkable after drillingof superior orbital fissure, foramen ovale, foramen rotundum, Fallopian canal, and jugularforamen.
    Full-text · Article · Dec 2004
  • I M Ziyal · K Ece · B Bilginer · G G Tezel · O E Ozcan
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    ABSTRACT: A 58-year-old male was admitted with headache to our neurosurgery clinic. His neurological examination revealed slight left hemiparesis. The radiological evaluation with contrast administred magnetic resonance imaging (MRI) scan demonstrated a right temporo-parietal ring enhancing mass lesion surrounded by edema which was resembling a typical glioma (Fig. 1). The patient was operated on via a temporo-parietal craniotomy and an arteriovenous malformation surrounded by abnormal glial tissue was observed during the exposure. A nidus supplied by several branches arising from the middle cerebral artery (MCA) was obvious. The venous drainage of the malformation was to the superficial venous system. The observed arterial feeders and the draining vein were coagulated and the nidus was macroscopically totally excised. The frozen examination from surrounding glial tissue revealed a high grade glioma. The tumor was also macroscopically totally excised. Postoperatively, the cerebral angiogram demonstrated a right temporal arteriovenous malformation with a centrally excised nidus. The remaining major feeders involved the angular gyrus and the posterior temporal arteries. The venous drainage was to the straight and sigmoid sinuses (Fig. 2). The final histopathological examination of the specimen revealed an arteriovenous malformation surrounded by a high grade glioma (Fig. 3). The patient refused a second operation for total removal of the AVM. Postoperatively, he is doing well with improvement of his left hemiparesis.
    No preview · Article · Feb 2004 · Acta Neurochirurgica
  • M Berker · S Gulsen · O E Ozcan
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    ABSTRACT: ¶We report a case of 57 year-old man with documented posttraumatic acute subdural hematoma and a linear temporal bone fracture. He suffered from a blunt head injury and presented with sudden loss of consciousness. Within 2 hours he became alert and oriented. Follow-up CT scan of brain 2 hours after the initial one showed resolution and redistribution of the subdural hematoma. To our knowledge, this is the first case in the literature about spontaneous resolution of an acute subdural hematoma in a patient with a linear fracture and the fastest resolution period. In this article, the authors discuss the underlying pathophysiology of this uncommon phenomenon.
    No preview · Article · Sep 2003 · Acta Neurochirurgica
  • M Berker · O Cataltepe · O E Ozcan
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    ABSTRACT: A series of 16 children (nine males, seven females) with traumatic epidural haematoma of the posterior fossa (TEHPF) is presented. All patients had a history of mild to moderate trauma to the occiput. The causes were falls in 15 and traffic accident in one case. Four of the 16 cases had depressed fractures of the occipital bone. Surgical intervention was performed in all cases. In 14 patients the outcome was good, one patient had moderate disability and one died. Our study revealed that early diagnosis and urgent surgical intervention may give the patient a chance of total recovery and craniotomy with haematoma evacuation is an appropriate surgical technique as in the case of supratentorial extradural hematoma.
    No preview · Article · Jul 2003 · British Journal of Neurosurgery
  • I M Ziyal · O E Ozcan · E Deniz · G Bozkurt · O Ismailoğlu

    No preview · Article · Mar 2003 · Acta Neurochirurgica
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    ABSTRACT: Basilar artery fenestrations are most commonly located in the proximal basilar trunk close to the vertebrobasilar junction and may harbor saccular aneurysms. Surgical treatment of such aneurysms has been reported in several cases previously, despite the difficulty of the surgical approach. Endovascular treatment may provide a more convenient treatment alternative in such cases. This case is also interesting in that two discrete aneurysms arise from each limb of the fenestration. A 20-year-old man presented with acute subarachnoid hemorrhage. He had two kissing aneurysms at the fenestrated proximal basilar artery as demonstrated by MRA and selective angiography. The two aneurysms were successfully treated with GDCs via the contralateral vertebral arteries. One-year control angiogram showed stable occlusion. Aneurysms at the fenestrated basilar artery may be effectively treated with endovascular coil occlusion. The occurrence of multiplicity and the treatment alternatives are discussed, with relevant literature review.
    No preview · Article · Aug 2002 · Surgical Neurology
  • T Ozgen · N Akalan · O E Ozcan · K Benli · S Palaoglu

    No preview · Article · Apr 2002 · Acta Neurochirurgica
  • B Cirak · M Alptekin · S Palaoglu · O E Ozcan · T Ozgen
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    ABSTRACT: Although lumbar spinal stenosis syndrome is extremely common, considerable controversy continues to surround its classification, diagnosis, and treatment. In this article, we retrospectively analyzed the clinical, radiological, and surgical characteristics of 300 patients operated on in our clinics with the diagnosis of lumbar spinal stenosis. Surgical therapy and outcome are discussed with respect to the known facts. After clinical and radiological evaluation, 300 patients were diagnosed with lumbar spinal stenosis. All patients underwent laminectomy and bilateral foraminotomy at the stenotic level. Surgical outcomes were evaluated as very good, good, same, and poor according to the clinical findings. Ninety percent of the surgically treated patients demonstrated very good and good outcomes. Our conclusion in lumbar spinal stenosis diagnosed by objective clinical and radiological findings is that decompressive laminectomy and extensive foraminotomy without instrumentation allow a good outcome.
    No preview · Article · Aug 2001 · Neurosurgical Review
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    ABSTRACT: The outcome of patients with pituitary adenomas who were treated surgically with or without postoperative radiotherapy was analyzed. The purpose of this study was to determine the factors that strongly influence (A) tumor control, (B) the efficacy of surgery, and (C) radiotherapy based on the hormonal activity of adenomas and its invasion characteristics. Between 1982-1996, 684 patients with the diagnosis of pituitary adenoma were operated on. The mean age was 38 years and the mean follow-up time was 40.5 months. A total of 516 patients who were followed for more than 1 year were studied to analyze the effect of treatment modalities and invasion characteristics on tumor control. There were 297 patients with prolactinomas, 118 patients with somatotropinomas, 45 with corticotropinomas, 17 with mixed adenomas, two with thyrotropinomas, and 205 with null cell adenomas. All patients were classified according to Hardy's modified radiological classification scheme and analyzed in invasive and noninvasive groups individually based on this classification system. In the early postoperative period, 230 of these patients were given conventional radiotherapy with a mean dose of 4400 cGy. The following factors were analyzed for prognostic significance in tumor control: the effects of surgery and radiotherapy based on tumor types and invasion characteristics, the existence of histologically proven invasion of the dura mater overlying the sellar floor, and the early results of topical bromocriptine application in macroprolactinoma patients. Overall surgical complications and mortality rate were similar to those of large series reported in the literature. Except for the invasive somatotropinomas and null cell adenomas, statistical analysis demonstrated the ineffectiveness of radiotherapy on tumor control. We did not detect any positive correlation between the recurrence rate and mean recurrence time or dural invasion of the sellar floor. Topical bromocriptine application seemed to improve tumor control in 21 selected macroprolactinoma patients. Conventional radiotherapy is not as effective as expected, considering its adverse effects. The increased side effects of radiotherapy in cases with supra-parasellar extension, especially to the optic pathway and hypothalamus, limit its benefits, which could be demonstrated only in invasive somatotropinomas and null cell adenomas. In contrast with our current beliefs, tumoral infiltration of the sellar dura mater is not a prognostic factor for recurrence and therefore should not be a criterion for radiotherapy after surgery. Topical application of bromocriptine into the sellar cavity after tumor removal seems to provide superior results compared with the conventional treatment modalities.
    No preview · Article · Apr 2000 · Surgical Neurology
  • H K Oge · F Söylemezoglu · N Rousan · O E Ozcan
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    ABSTRACT: Spinal extradural angiolipomas are distinct, benign, and rare lesions composed of mature lipocytes admixed with abnormal blood vessels. They account for 0.14% of all spinal axis tumors. The case described here was a 72-year-old patient presenting with a history of paraparesis, hypoesthesia under the T2 level, hyperreflexia, and urinary overflow incontinence that appeared within 7 days after the administration of a coronary vasodilator drug regimen. The spinal magnetic resonance scan showed a lipomatous mass with signal void lesions, suggesting a vascular component of the tumor. The patient improved rapidly after surgical resection of the epidural tumor and decompression of the cord. According to the present literature, the duration of neurological symptoms ranges from 1 to 180 months (mean 28 months). But this patient's neurological deterioration took place 4 days before hospitalization. We believe that this can be explained by the increased tumor blood volume caused by vasodilator drugs, which in turn exerted a pulsatile compressive effect on the cord.
    No preview · Article · Sep 1999 · Journal of Spinal Disorders
  • T Ozgen · H H Oruckaptan · O E Ozcan · B Acikgoz
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    ABSTRACT: We performed this retrospective analysis to determine the efficacy of surgery and radiotherapy over hormonal and volumetric control of prolactinomas, many of which had failed during dopa-agonist therapy. In the same analysis, the efficiency of topical bromocriptine application as a preliminary study was compared with standard treatment modalities. Between 1982-1997, 429 prolactinoma patients who underwent surgery at Hacettepe University Neurosurgery Department and at Bayindir Medical Center were included in this study. All patients were classified according to Hardy's classification scheme and were further divided into 'invasive' and 'non-invasive' groups based on this radiological classification system. The mean follow-up time was 38.4 months. One hundred and thirty five patients had peroperative bromocriptine application into the sellar cavity and these, either receiving radiotherapy (RT) or not, were analysed separately from the other 294 patients. In the early post-operative period, 104 of these patients were given conventional radiotherapy with median dose of 4500 cGy. We focused on the effects of surgery and radiotherapy over volumetric and hormonal tumour control on the basis of invasion characteristics and the early results of topical bromocriptine application in macroprolactinoma patients; and compared our results with the literature. Statistical analysis revealed that radiotherapy was not effective over hormonal and volumetric tumour control for prolactinomas. We did not observe any correlation to dural invasion of the sellar floor, recurrence, and the disease-free survival time. Topical bromocriptine application seemed to improve the volumetric control in 135 selected macroprolactinoma patients but not hormonal response compared with the standard treatment modalities. Conventional radiotherapy is not as effective as expected for prolactinomas and should not be preferred considering its adverse effects. Tumoural infiltration of the sellar dura mater is not a prognostic criterion for recurrence expectation and, therefore, should not be a criterion for radiotherapy after surgery. After subtotal removal, postoperative dopa-agonist therapy should be considered even if the patient was intolerant or resistant to previous treatment since surgery seems to improve patients' drug tolerance and cooperation due probably to the lower dose requirement. The early results of topical bromocriptine application seem to improve volumetric tumour control but this should not be accepted as a judgement since we need to wait for later results and to expand the sample size for more reliable interpretation.
    No preview · Article · Feb 1999 · Acta Neurochirurgica
  • T. Suzer · K. Tahta · H. Celik · O.E. Ozcan
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    ABSTRACT: The purpose of this study was to investigate the preventive effect of Ticlopidine on thrombus formation after surgical arterial injury. The model of microsurgical carotid endarterectomy was performed on the common carotid arteries in rats. Twenty rats were equally divided into two groups: a control group that received no drugs and a Ticlopidine-treated group (100mg/kg orally 3 hours before surgery). The vessels were prepared for scanning electron microscopy and were evaluated based on the platelet aggregates at the endarterectomized site. The Mann-Whitney U test identified a statistically significant difference between the control group and the drug-treated group (U=82.50, p< 0.05). This study proves that Ticlopidine has a preventive effect on platelet aggregation in endarterectomized carotid arteries and that it can be used to reduce postoperative thrombus formation after carotid endarterectomy.
    No preview · Article · Jan 1999
  • S Inci · O E Ozcan · K Kilinç
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    ABSTRACT: 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. 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. 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. 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.
    No preview · Article · Sep 1998 · Neurosurgery
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    ABSTRACT: NF-2 is an extremely rare form of neurofibromatosis (NF) characterized by central system (CNS) neural crest-derived tumors and frequently cafe au lait spots (CLS). The purpose of this study was to report the clinical and imaging findings of seven patients with this disorder and to stress that value of surgical treatment in its management. Seven patients between 8 and 32 years of age who had NF-2 were included in the study. Clinical charts, surgical and pathological findings, and imaging studies were reviewed retrospectively. Patients were followed up for to 142 months. Clinical evaluation and neuroimaging studies detected the clinical criteria of NF-2 in all patients. Two deaths occurred after surgical intervention in our series. None of the patients suffered from recurrent tumor following surgery. Our results show that NF-2 is an uncommon entity which has a good prognosis after surgical intervention, in spite of the presence of multiple cranial and/or spinal lesions.
    No preview · Article · Feb 1998 · Neurosurgical Review
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    ABSTRACT: A review of nasopharyngeal carcinomas (NPCs) treated in the Hacettepe University Hospitals is presented. One hundred twenty-four patients between the ages of 3 years and 72 years were managed in the period 1968-1992. Of these cases, 48 had only cranial nerve (CN) involvement on admission. The most commonly affected CNs were the VIth and the Vth, in that order. The prognostic significance of this finding is obvious, because early diagnosis and treatment is vital in a cancer patient. This study includes retrospective analysis of 124 patients with NPC. The patients were investigated with respect to clinical and radiological diagnosis and outcome. Our results also show that CN involvement in NPC usually requires careful neuro-otological examination. It is suggested that increased knowledge and understanding of the disease among neurosurgeons, neurologists and ENT surgeons would improve the prognosis of patients with NPC.
    No preview · Article · Feb 1998 · Neurosurgical Review
  • Mehmet Turgut · Kadir Tahta · O E Ozcan · B Onol
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    ABSTRACT: Oligodendrogliomas are relatively rare tumors that arise from the oligodendrocyte or its precursors. The role of postoperative radiotherapy (RT) in these tumors still remains unclear. Data concerning a study on 77 histologically verified cases of oligodendrogliomas of the brain among a total number of 1884 cases of an intracranial glioma treated at the Hacettepe Medical Centre between 1964 and 1991 were reviewed and analyzed (6.5%). One patient died in the early postoperative period and 8 patients in pediatric age group with an aggressive from of the tumor died within 6 months of treatment. The results suggest that oligodendrogliomas which arise in childhood primarily in the intraventricular region should be considered potentially more malignant than other lesions of this type. Because of this, we believe that postoperative radiotherapy is necessary to prevent the recurrences.
    No preview · Article · Feb 1998 · Neurosurgical Review
  • M Turgut · O E Ozcan · V Bertan
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    ABSTRACT: Meningiomas are relatively uncommon in childhood. They represent 1 to 2% of all intracranial tumours of infancy and childhood. During the last 30-year period, from 1964 to 1993, 13 children with a diagnosis of meningioma were operated on at the Department of Neurosurgery, Hacettepe University School of Medicine. The meningiomas in the paediatric age group were characterized by multiplicity (23%), frequent association with neurofibromatosis (23%), intraventricular location (8%), and the presence of a cystic component in the tumour tissue (23%). These findings in children differ from those in adults. This study constitutes a retrospective analysis of these cases and a review of the literature.
    No preview · Article · Jan 1998 · British Journal of Neurosurgery