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Dive into the research topics where Nejat Isik is active.

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Featured researches published by Nejat Isik.


Journal of Clinical Microbiology | 2007

Nocardial Cerebral Abscess Associated with Mycetoma, Pneumonia, and Membranoproliferative Glomerulonephritis

Ilhan Elmaci; Durmus Senday; Gökalp Silav; Figen Ekenel; Naci Balak; Erdogan Ayan; Murat Akinci; Nejat Isik; Saadet Yazici

ABSTRACT Nocardial brain abscesses remain a clinical challenge. We successfully treated a patient with nocardial brain abscess, mycetoma, pneumonia, and glomerulonephritis. Nocardial soft tissue involvement, mycetoma, is well known. However, the fact that actinomycetoma can metastasize may not be as well appreciated. The association between nocardiosis and glomerulonephritis should be better clarified.


Pediatric Neurosurgery | 2010

Currarino Triad: Surgical Management and Follow-Up Results of Three Cases

Nejat Isik; Ilhan Elmaci; Bekir Gokben; Naci Balak; Nadir Tosyalı

The Currarino syndrome is a rare triad that is a combination of a presacral mass, a congenital sacral bony abnormality and an anorectal malformation. We present 4 children with complete Currarino triad who were diagnosed using MRI. Our aim was to report the neurosurgical management of Currarino syndrome in children. All of the patients had chronic constipation and pain in the lumbosacral region. In the plain radiograph, 3 patients had a sacral scimitar-shaped bony abnormality, and 1 patient had total sacral agenesis. There was a narrow anal canal or narrow ventrally displaced anus in all patients. Their anorectal malformations were characterized as anal stenoses (4 patients), associated with Hirschsprung’s disease in 2 cases. In 3 patients, MRI showed tethered cord syndrome in addition to the presacral mass. There was hydrocephalus in 1 patient. Anal stenosis was treated by anal dilatation. In 2 patients, rectal biopsy and temporary colostomy (2 patients) had been performed previously due to Hirschsprung’s disease. We performed a posterior procedure via lumbar and sacral partial laminectomy-laminoplasty and transdural ligation of the neck of the meningocele for anterior sacral meningoceles, or alternatively, tumor excision for other types of presacral lesions. Histopathologically, 3 were cases of anterior sacral meningoceles and 1 was a teratoma. One of them also had a spinal abscess. He required reoperation (twice) and appeared at the time to have improved with medical therapy. All patients improved and stabilized. There were no additional neurological deficits and no recurrence of the presacral mass over the follow-up period (6 years, on average). The family pedigree did not reveal any familial transmission pattern. In cases of Currarino triad, MRI can allow the characterization of the presacral masses. If it is an anterior sacral meningocele or a solid tumor without severe anorectal malformation, it can be managed with posterior lumbar and sacral procedures. Such approaches are performed easily by transdural ligation of the neck of the anterior sacral meningocele or through tumor excision.


Archive | 2008

Microsurgical treatment of unruptured intracranial aneurysms

Naci Balak; Cerci A; A. Şerefhan; K. Coşkun; Ramazan Sari; Nejat Isik; İlhan Elmaci

Summary Background. The natural history of unruptured cerebral aneurysms is not clearly defined. Method. Fifteen patients who were diagnosed with unruptured intracranial aneurysms and were surgically treated by clipping at our hospital during the years 2004–2005 were studied retrospectively. Findings. There was no mortality. Early morbidity in this study was 6.6%. One patient developed symptomatic vasospasm after the surgery. Conclusions. In this study, the microsurgical treatment of intracranial unruptured aneurysms was found to be a safe intervention and prevented the possibility of the patients developing subarachnoid haemorrhage, which has high mortality and morbidity.


British Journal of Neurosurgery | 2013

Long-term results and complications of the syringopleural shunting for treatment of syringomyelia: a clinical study

Nejat Isik; Ilhan Elmaci; Cerci Sa; Recep Basaran; Gura M; Kalelioglu M

Abstract Background. The use of drains in the treatment of syringomyelia has a simple and immediate appeal. Syringopleural shunting in syringomyelia has produced good short-term results, but limited information is available on long-term effects. We analyzed the complications and long-term outcomes after syringopleural shunting for syringomyelia. Clinical material and methods. Fourthy-four patients with large-sized syringomyelia underwent syringopleural shunting because of spinal cord compression between 1992 and 2010 in our clinic. Thirty-two patients had Chiari malformation type I (Group B), and 12 patients were associated with primary parenchymal cavitations (Group A). Their ages ranged from 14 to 71 years. Both craniovertebral decompression and syringopleural shunting were performed on 21 patients, whereas only syringopleural shunting was performed on another 21 patients. Results. The follow-up period ranged from 1 year to 17 years (mean: 9.1 years). There was no operative mortality. Early postoperative MRI revealed that syringes of 43 patients had collapsed. There were 9 (20.5%) minor complications in 9 patients, including temporary neurological deficits (6), respiratory distress (2) and headache (1). Seven (15.9%) serious complications [permanent neurological deficit (1), shunt migration (2), shunt misplacement (1), spinal instability (1), tethering (1), CSF over drainage (1)] were seen in five patients. Four of them were treated with a secondary operation. Three patients (3/9; 33.3%) who were treated by syringopleural shunt alone (Group B2) required craniovertebral decompression, although the shunt was functional. During long-term follow-up, three patients stabilized, five patients (11.3%) developed a worse neurological condition, and two of these patients died 10 and 7 years after surgery. Of all patients, 88.6% showed significant clinical improvement. Conclusions. Although there were complications and failures, syringopleural shunting produced satisfactory results at long-term follow-up.


Clinical Anatomy | 2010

Microsurgical and histomorphometric study of the occipital sinus: quantitative measurements using a novel approach of stereology.

Naci Balak; Gökhan Ersoy; Ünal Uslu; Necmettin Tanriover; Leyla Tapul; Gürsel Çetin; Nejat Isik; Ilhan Elmaci

Quantitative descriptions of the occipital sinus are lacking in the extant medical literature. Posterior fossa duras with the superior sagittal sinus, the inferior and superior petrosal sinuses were dissected and taken out from fresh human cadavers by cutting at the superior sagittal sinus, the marginal sinuses and the petrosal sinuses bilaterally. The length of the occipital sinuses was measured using calipers. A 0.5‐cm section of the occipital sinus was cut out at its midpoint and prepared for measurements of the perimeter and diameter using a stereology workstation. The sinuses were also examined qualitatively using a surgical microscope. There was no occipital sinus in 6.6% of total 30 cases. Multiple occipital sinuses were seen in 10%. In one specimen, the sinus seemed incomplete, failing to reach the marginal sinuses. Some specimens gave the impression that more than one occipital sinus was present, nevertheless, careful dissection showed connections. The breadth of the sinus steadily narrowed downward in direction of foramen magnum. The inner wall with many fibrous bridges was tight, except the lateral parts that were easily separated into two dural sheets. The length of the sinus varied from 10 to 37 mm. The inner diameter (feret maximum) varied from 0.33 to 7.06 mm at midpoint. The breadth of the multiple sinuses did not exceed the mean of our series except in one case. The occipital sinus, which is generally ellipsoid in shape, functions in the majority of cases as a thin, single midline sinus. It may have less resistant recesses laterally. Clin. Anat. 23:386–393, 2010.


Pediatric Neurosurgery | 2009

Chiari Malformation Type III and Results of Surgery: A Clinical Study

Nejat Isik; Ilhan Elmaci; Gökalp Silav; M. Çelik; M. Kalelioğlu

Background: The characteristics of Chiari malformation type III and its treatment are evaluated in this study. Radiological and surgical findings were correlated and the benefits of the therapy are discussed. Methods: Eight patients (6 males, 2 females) with Chiari malformation type III were studied. All patients underwent surgery to remove encephalocele along with neural tissue and to repair the dura and the skin. Associated pathologies such as hydrocephalus, tethered cord syndrome and syringomyelia were also surgically treated. Follow-up was based on the evaluation of postoperative motor and mental development, as well as on magnetic resonance imaging findings. Results: Ventriculoperitoneal shunt malfunction in 2 patients was the only surgical complication. One patient died 10 days after the operation, 7 patients survived, and the outcome of 2 patients was quite poor because of severe mental retardation and neurological deficits at the beginning. In the remaining patients, motor and mental development was normal, and the neurological outcome was satisfactory. Conclusion: Surgery in the newborn period, initial severity of neurological deficits, the presence of intermittent apnoea, delayed treatment of hydrocephalus and the amount of neuronal tissue within the excised encephalocele were determined as unfavourable prognostic factors for the outcome. If the appropriate surgical procedure is done at the right time, the outcome of the Chiari malformation type III patient can be satisfactory with a low mortality rate.


Neurocirugia | 2013

Microsurgical management of non-neurofibromatosis spinal schwannoma

Murat Altaş; Cerci A; Gökalp Silav; Ramazan Sari; Kenan Coşkun; Naci Balak; Nejat Isik; İlhan Elmaci

INTRODUCTION The aim of this study is to assess the clinical properties and surgical results of patients diagnosed with spinal schwannomas without neurofibromatosis (NF) properties. PATIENTS AND METHODS The data obtained from 35 patients who underwent resection of spinal schwannomas were analyzed. All cases with neurofibromas and those with a known diagnosis of NF Type 1 or 2 were excluded. 35 patients underwent surgery for spinal schwannoma at our institution between January 1997 and 2010. The data were gathered retrospectively from medical records and included clinical presentation, tumor location and post-operative complications. All cases were surgically excised, and they were confirmed to be schwannomas by pathologists with histopathological sections in paraffin stained with hematoxylin-eosin. RESULT We treated 35 (20 males and 15 females) patients with spinal schwannomas. The mean age of the patients was 47.2 (between 13 and 76) years. Of the cases, six schwannomas were located in the cervical spine, four in the thoracic spine, two in cervico-thoracic area, 10 in the thoraco-lumbar area and 13 in the lumbar spine. Two patients had malignant schwannomas that were recurrent. Of the 35 cases, the schwannomas were intradural-extramedullary in 30 cases (86%), intradural-intramedullar in 2 cases (6%), and extradural in 3 cases (9%). CONCLUSION Spinal schwannomas may occur at any level of the spinal axis and are most frequently intradural-extramedullary. The most common clinical presentation is pain. Most of the spinal schwannomas in non-NF patients can be resected completely without or with minor post-operative deficits. This knowledge may help us to create a strategy for total resection of a spinal schwannomas.


Apmis | 2015

Correlation between SPARC (Osteonectin) expression with immunophenotypical and invasion characteristics of pituitary adenomas

Mustafa Onoz; Recep Basaran; Berrin Gucluer; Nejat Isik; Tuncay Kaner; Aydin Sav; Ilhan Elmaci

Pituitary adenomas are the third most common intracranial tumors. Invasive adenomas account for only 0.1–0.2% of pituitary tumors. SPARC is a matrix glycoprotein that plays a role in progression and invasiveness of neoplasms. In this study, we examined the potential role of SPARC in invasive pituitary adenomas. Forty pituitary adenomas have been examined with histopathological and immunohistochemical techniques. The cohort has been classified into two groups as invasive (n = 25) and non‐invasive (n = 15) utilizing the Hardy classification. Formalin fixed tissues have been stained with hematoxylin eosin. Ki‐67, p53, and SPARC monoclonal antibodies have been used. We did not detect any significant difference on Ki‐67, SPARC, and p53 expression patterns correlating with the pathological subtype or invasiveness. Only 24% of invasive adenomas had Ki‐67 levels over 1%. A total of 67.7% non‐invasive adenomas had Ki‐67 levels below 1%. We did not detect any relation between SPARC levels and invasiveness of pituitary adenomas. Absence of significant SPARC expression in tumor progression, sellar dilatation, erosion and destruction suggest that SPARC scores are not related with invasiveness or progressiveness of pituitary adenomas.


Journal of Pediatric Neurosciences | 2014

Desmoplastic infantile ganglioglioma: Report of an unusual case with a cranial defect

Recep Basaran; Fatma Betul Cakir; Nejat Isik; Aydin Sav; Ilhan Elmaci

Desmoplastic infantile ganglioglioma (DIG) is a rare tumor that typically occurs in infants under the age of 24 months. These tumors commonly have a good prognosis after surgical resection despite their aggressive radiological appearances. Clinical signs are due to the large size of the tumor and include increased head circumference, bulging fontanel, sunset sign and seizures. We report an unusual DIG case who presented with parietal bulging associated with a bony defect. The patient was thought to have a leptomeningeal cystic formation, but on his cranial magnetic resonance imaging (MRI), we observed a centrally and homogeneously gadolinium-enhanced lesion fixed to the dura by its solid component. A surgical gross total resection was performed, and no residual tumor was observed on follow-up.


Turkish Neurosurgery | 2014

The Acute and Delayed Effects of Vagal Nerve Stimulation on an Absence Epilepsy Model in WAG/Rij.

Ramazan Uyar; Cezmi Çağrı Türk; Nejat Isik; Müfit Kalelioğlu; Filiz Onat; Memet Ozek

AIM Vagal nerve stimulation (VNS) is an effective method of treatment for epilepsy patients either unresponsive to medical therapy or not suitable for resective surgeries. We designed an experimental study on Wistar Albino Glaxo rats from Rijswijk (WAGRij) to investigate the effects of VNS on a non-convulsive epilepsy model. MATERIAL AND METHODS The experiment was performed on six WAG/Rij rats, a validated strain for genetic absence seizures. The animals were underwent VNS and the effects were investigated on electroencephalography (EEG) recordings at 22, 24, 26 hours of stimulation and 15 days after the cessation, for duration of spike and wave complexes (SWC), the numbers, mean duration of SWC and frequencies in an hour. RESULTS EEG recordings demonstrated that the mean duration of SWC was 353.1 seconds and the number of activity per hour was 62 at the baseline. There were statistically significant decreases in the total duration of SWC and the number of activities (61.8% and 78% decrease, respectively). There were no significant decreases in the mean duration of SWC and the frequencies. CONCLUSION The acute stimulation of the vagal nerve caused a statistically significant decrease both in overall duration of SWC and the number of complexes in an hour. Moreover, the positive effects seemed to last even 15 days after the cessation of the stimulation. Further studies focusing on different stimulation parameters and delayed effects of the VNS on human absence seizures are warranted.

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Ilhan Elmaci

Johns Hopkins University

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Recep Basaran

Istanbul Medeniyet University

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Ilhan Elmaci

Johns Hopkins University

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Murat Altaş

Mustafa Kemal University

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Mustafa Efendioglu

Istanbul Medeniyet University

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Nihal Isik

Bahçeşehir University

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Tuncay Kaner

Istanbul Medeniyet University

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Mustafa Onoz

Memorial Hospital of South Bend

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