Browsing by Author "Dere, Umit Akin"

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Cervical Spinal Ependymoma With Hemorrhage in a Renal Transplant Patient
(2022) Sahinturk, Fikret; Dere, Umit Akin; Kirnap, Mahir; Sonmez, Erkin; Altinors, Nur; Ozen, Ozlem; Haberal, Mehmet; https://orcid.org/0000-0002-0471-3177; https://orcid.org/0000-0002-6678-6224; 30251937; AAI-7972-2021; N-1435-2014
Ependymomas are the most common intramedullary spinal tumors in adults and constitute around 20% of all spinal tumors in adults. There are 3 subgroups of ependymomas according to World Health Organization classification: subependymoma or myxopapillary (grade 1), ependymoma (grade 2), and anaplastic (grade 3). Therapy for patients is aimed at safe and total surgical removal and, in selected cases, postoperative radiotherapy. Bleeding from a spinal ependymoma, with subsequent urgent surgery, is extremely rare. Here, we present a case of a renal transplant patient who had a cervical ependymoma. Although a considerable volume of peritumoral blood was observed during surgery, the patient had no neurologic deficits and no signs of deterioration.
Characterizing the Intraoperative Microelectrode Recording-Induced Microlesion Effect on Motor Symptoms in Patients with Parkinson's Disease Undergoing Deep Brain Stimulation of the Subthalamic Nucleus
(2019) Aygun, Dursun; Dere, Umit Akin; Yildiz, Onur; Temel, Yasin; Kocabicak, Ersoy; 30649828
AIM: To investigate microelectrode recording (MER)-induced microlesion effect (MLE) on the motor symptoms of 30 patients with Parkinson's disease (PD) who underwent deep brain stimulation of the subthalamic nucleus. MATERIAL and METHODS: MER-induced MLE was evaluated based on the difference between tremor, rigidity, and bradykinesia scores in the preoperative off-state and intraoperative state following MER and before test stimulation. RESULTS: MLE scores improved by 21.7% [left (L) side] and by 13.6% [right (R) side] from baseline (p<0.05). Tremor scores improved by 31.5% (L) and by 14.2% (R) (p<0.05), rigidity scores improved by 17.3% (L) and by 14.2% (R) (p<0.05) and bradykinesia scores improved by 20.6% (L) and by 11.5% (R) (p<0.05) from baseline. There was no significant difference between MLE and the number of microelectrodes used (p> 0.05). CONCLUSION: MER-induced MLE improved motor symptoms and was not correlated with the number of microelectrodes used during the procedure.
Effects of Quercetin on Chronic Constriction Nerve Injury in an Experimental Rat Model
(2016) Civi, Soner; Emmez, Gokcen; Dere, Umit Akin; Borcek, Alp Ozgun; Emmez, Hakan; https://orcid.org/0000-0002-1055-5152; 26960544; U-2400-2018
Flavonoids are popular substances in the literature, with proven effects on cardiovascular, neoplastic and neurodegenerative diseases. Antioxidant effect is the most pronounced and studied one. Among thousands of flavonoids, quercetin (QUE) is a prototype with significant antioxidant effects. This study aims to demonstrate the effects of QUE in an experimental rat model of chronic constriction injury (CCI). A two-level study was designed with 42 adult Wistar rats that were randomly assigned to different groups. In the first part, animals in sham, control, quercetin, morphine and gabapentine groups received chronic constriction injury to their sciatic nerves and received a single dose of QUE, morphine and gabapentine. In the second part, different dose regimens of QUE were administered to different groups of animals. Pre-injury and post-injury assessments for mechanical hypersensitivity, thermal sensitivity, locomotor activity and anxiety were recorded and statistical comparisons were performed between different groups. Comparison of QUE with morphine and gabapentine has revealed significant effects of this agent in the current chronic constriction injury model. QUE was significantly superior to Gabapentine and morphine in terms of alleviating mechanical and thermal hypersensitivity. Additionally, pre-injury administration of QUE for 4 days demonstrated long-term effectiveness on mechanical hypersensitivity. This preliminary report the on effects of QUE in a chronic constriction injury model proved significant effects of the agent, which should be supplemented with different studies using different dose regimens.
Intracranial chondroma without meningeal attachment
(2018) Dere, Umit Akin; Oktay, Kadir; Arslan, Murat; Kesen, Sevcihan; Ciftci, Tufan; 0000-0002-6678-6224; 29766963
Intracranial Fungal Infection After Solid-Organ Transplant
(2018) Sahinturk, Fikret; Demirkaya, Hamiyet; Dere, Umit Akin; Sonmez, Erkin; Altinors, Nur; Moray, Gokhan; Haberal, Mehmet; 0000-0002-0471-3177; 0000-0002-6678-6224; 0000-0002-5693-3542; 0000-0003-2498-7287; 0000-0002-3462-7632; 29528023; AAI-7972-2021; N-1435-2014; AAI-8820-2021; AAE-1041-2021; AAJ-8097-2021
Neurologic complications after solid-organ transplant reveal a great spectrum of pathologies. Intracranial hemorrhages, cerebral ischemic lesions, infarctions, lymphoproliferative disorders, and infections, including aspergillosis, have been observed after liver transplant. Fungi constitute nearly 5% of all central nervous system infections, mainly occurring in immunocompromised patients. The most common causative agent is Aspergillus species. It presents either as maxillary sinusitis or pulmonary infection. Brain involvement of Aspergillus carries a high rate of mortality. Aspergillosis presents in the forms of meningitis, mycotic aneurysms, infarctions, and mass lesions. Aspergillosis does not have a specific radiologic appearance. Parenchymal aspergillosis has heterogenous signal intensity (hypointense on T1-weighted and hyperintense on T2-weighted images). Here, we present 3 patients who underwent solid-organ transplant and developed central nervous system aspergillosis. Different modalities of neurosurgical intervention were performed in combination with chemotherapy as part of their fungal therapy.
Sacral Spine Eosinophilic Granuloma in an Adult Patient: A Case Report of Unusual Age and Location
(2018) Dere, Umit Akin; Aslan, Ayfer; Kaymaz, A. Memduh
Eosinophilic granuloma one of a triad of diseases under Langerhans' cell histiocytosis as known as Histiocytosis X, is a rare disorder characterized with uncontrolled proliferation of histiocytes, mostly seen among children and adolescents instead of adults. Although the clinical picture is well defined, there are still unclear aspects on etiology, histology and prognosis. Here we are presenting our experiences on a case of eosinophilic granuloma interestingly in an adult patient. She was admitted with back and hip pain. After her diagnosis of sacral spine osteolytic tumor, the biopsy was performed in our clinic and her histopathology was resulted as eosinophilic granuloma. In this paper we are presenting the clinical and hystopathological features of esonophilic granuloma. We aimed to contribute an additional data to the literature on eosinophilic granuloma presented with an atypical localization and age. According to current literature, there are only few reports on both adults and sacrum affected with eosinophilic granuloma.
Stereotaxic Biopsy Experience
(2020) Dere, Umit Akin; Sahinturk, Fikret; Sonmez, Erkin; Gulsen, Salih; Yilmaz, Cem; Altinors, Mehmet Nur
Aim: To review the outcomes and complications of stereotactic biopsy procedures performed at Neurosurgery Department of Baskent University and make an overall evaluation of the stereotactic biopsy system. Materials and Methods: Medical files of 151 patients who underwent stereotaxic biopsy procedure between 1996 and 2018 were retrospectively analyzed.The , age and gender of the patients, intracranial localization of the lesion and histopathologic diagnosis were evaluated. Result: The series included 84(55.6%) males and 67 (44.4%) females. The average age was 47.7 and the age spectrum was between 26-84 years of age. In 102 cases (67.55%) lesions had lobar localization and in 42 lesions (27.82%) the pathology was deep seated lesion. In 7(4.6 %) there were multiple lesions. A histopathologic diagnosis was obtained in 125 (82.79 %) cases. In 16 (%10.59 %) it was reported as brain tissue and in 10 cases (6.62 %) the histopathologic diagnosis was gliosis. A second stereotactic bipsy procedure was performed in 8 cases while in one patient a third biopsy became necessary. Thirteen patients underwent craniotomy and tumor excision as further therapy. Conclusion: Stereotactic biopsy sampling of intracranial space occupying lesions is a safe, simple and highly diagnostic method. In some cases it may contribute to further therapy. The problems encountered are inconclusive diagnosis, inadequate representation of the specimen due to its limited nature and some technical difficulties.
Vertebral Body Lipoma An Unusual Pathology Treated With Kyphoplasty
(2018) Sahinturk, Fikret; Dere, Umit Akin; Sonmez, Erkin; Altinors, Nur; Terzi, Aysen; 0000-0002-0471-3177; 0000-0002-6678-6224; 0000-0002-5693-3542; 0000-0002-1225-1320; 30226833; AAI-7972-2021; N-1435-2014; AAI-8820-2021; F-7546-2013
Study Design. Case report. Objective. This case report is unique since this is the first vertebral lipom case that was treated by kyphoplasty alone. Summary of Background Data. Vertebral lipoma is extremely rare and our search of the English literature has revealed 20 patients in 16 reports. Methods. A 32-year-old female patient was admitted to our neurosurgery department with the chief complaint of low back pain that had lasted nearly 1 year. A lumbar MR suggested a hemangioma and the patient was operated on. Results. On microscopic examination, the lesion was seen to have a widely infiltrating appearance of mature fat tissue between bone trabeculae diagnosis was intraosseous lipoma. Conclusion. We believe that the management should be surgical total removal of the lesion even in incidentally found cases in order to obtain histologic diagnosis and pain relief.