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Dive into the research topics where Mahmut Akyuz is active.

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Featured researches published by Mahmut Akyuz.


Neuroradiology | 2009

CT angiography and perfusion imaging in patients with subarachnoid hemorrhage: correlation of vasospasm to perfusion abnormality

Ayse Aralasmak; Mahmut Akyuz; Can Özkaynak; Timur Sindel; Recai Tuncer

IntroductionWe retrospectively evaluated computed tomography angiography (CTA) and perfusion imaging (CTP) of patients with aneurysmal subarachnoid hemorrhage (SAH) for any correlation between degree of vasospasm and perfusion deficit.Materials and methodsSequentially performed CTP and CTA of 41 patients at least at the third day of postbleeding were reviewed for vasospasm and perfusion deficit throughout the anterior and middle cerebral arteries and corresponding territories. Vasospasm was noted comparing the contralateral normal ones or extradural components of the vessel itself and graded to negative, mild, moderate, and severe as luminal narrowing none, <25%, between 25% and 50%, and ≥50%, respectively. CTP abnormality was noted using cerebral blood flow and volume and mean transit time maps.ResultsOf 41 patients, 20 had no vasospasm; 15 had mild to moderate and six had severe vasospasm. Three of 20 patients with no vasospasm (15%), four of 15 patients with mild to moderate vasospasm (26%), and five of six patients with severe vasospasm (83%) had perfusion abnormality. Perfusion abnormalities noted were ischemia, infarction, and hyperperfusion. Perfusion abnormality without vasospasm was observed in the watershed areas and adjacent to sulcal clots.ConclusionIn SAH patients, if there is a macrovascular vasospasm with luminal narrowing ≥50%, there is a high likelihood (83%) of perfusion abnormality in the territory of the vasospastic vessel. There may also be perfusion abnormality without macrovascular vasospasm in the watershed areas or in the vicinity of sulcal clots.


Acta Neurochirurgica | 2002

Complications of closed continuous lumbar drainage of cerebrospinal fluid.

S. C. Açıkbaş; Mahmut Akyuz; Saim Kazan; Recai Tuncer

Summary. Sixty three patients who had a lumbar subarachnoid catheter placed for closed continuous cerebrospinal fluid drainage and the complications are presented. The drain was successful in achieving the desired goal in 59 patients (93,6%). The complications are mainly divided into 3 groups; A – complications related to alterations in CSF drainage rate, B – complications due to mechanical failure of the catheter, C – infection. The overall complication rate is found to be 44,4%. Overdrainage, pneumocephalus and meningitis are found to be the most severe complications, but most of these complications are reversible with early recognition. Unfortunately one patient died following meningitis and hepatic failure. Lumbar subarachnoid drainage is a safe method unless the development of any neurological findings should prompt rapid discontinuation of lumbar drainage and immediate radiographic evaluation.


British Journal of Neurosurgery | 2004

A thoracic complication of ventriculoperitoneal shunt: symptomatic hydrothorax from intrathoracic migration of a ventriculoperitoneal shunt catheter.

Mahmut Akyuz; T UÇar; Ethem Göksu

Thoracic complications of ventriculoperitoneal (VP) shunt are very rare. We report an unusual case of VP shunt intrathoracic migration, associated with symptomatic hydrothorax. The patient was successfully managed with revision. We reviewed the 10 cases reported in the literature and discussed the mechanism of shunt – tip migration.


Acta Neurochirurgica | 2006

The effects of fenestration of the interpeduncular cistern membrane arousted to the opening of lamina terminalis in patients with ruptured ACoA aneurysms: a prospective, comparative study

Mahmut Akyuz; Recai Tuncer

SummaryBackground. The incidence of chronic hydrocephalus requiring shunt placement is a well-known and common complication of aneurysmal subarachnoid hemorrhage (aSAH). It was suggested that fenestration of the lamina terminalis (LT) during microsurgery for aSAH may be associated with a reduced rate of shunt-dependent chronic hydrocephalus (SDCH). We analyzed that, fenestrations of the LT and Liliequist membrane (LM) would reduce rate of SDCH and improve rate of favorable outcome. Methods. 145 patients who were analyzed in the study were treated in our department with ruptured anterior communicating artery (ACoA) aneurysms. We compared the rate of shunting and clinical outcome in patients in whom only fenestration of the LT (Group 1) was performed with that in patients in whom fenestrations of both the LT and LM (Group 2) were performed. Results. Chronic hydrocephalus requiring shunting amounted to 9.8% (7 patients) in Group 1 and 4% (3 patients) in Group 2 (p = 0.203). Also, there were no differences in the rate of shunt dependent hydrocephalus between the two groups in patients with Fisher’s CT grades 3 (p = 0.343) and 4 (p = 0.667), and HH grades 4 (p = 0.306) and 5 (p = 0.361). Favorable clinical outcomes were observed with rates of 74.6% in Group 1 and 79.7% in Group 2 (p = 0.693). Also there were no differences in the rates of favorable clinical outcome between the two groups in patients with Fisher’s CT grades 3–4, HH grades 4–5. Conclusions. Our study shows that fenestration of the LM coupled with the opening of the LT reduced-relatively-the incidence of SDCH; this however was not significant. This positive effect was particularly noticeable in patients in whom a cisternal “overflow” was observed at surgery when opening the LM. This corresponded to cases with ventricular dilatation and a IVth ventricle with clots.


Acta Neurochirurgica | 2004

Angiographic follow-up after surgical treatment of intracranial aneurysms

Mahmut Akyuz; Recai Tuncer; S. Yılmaz; Timur Sindel

SummaryThis study was undertaken to evaluate the long-term angiographic outcome of surgically treated aneurysms. In addition, the incidence of recurrent aneurysms, the fate of residual aneurysms and the de novo formation of aneurysms were evaluated. Moreover, morphological conditions such as dilatation, stenosis or irregularity in temporarily clipped vascular segments were analyzed.166 aneurysms were operated on in 136 patients and these 166 aneurysms subsequently underwent late follow-up angiography. Late angiographic follow-up review was obtained at a mean of 46.6±11.5 months postsurgery (range 36–85 months). Out of the 7 aneurysms with known residua, 5 residual aneurysms were determined as unchanged, 1 residual aneurysm as spontaneous thrombosis and 1 residual aneurysm as enlarged. No recurrent aneurysm was found, however two de novo aneurysms were found. During the surgery of 85 anuerysms, 137 vascular segments clipped temporarily were evaluated in terms of morphological changes in postoperative and long-term angiograms. No morphological changes were determined in any vascular segments.These anatomical long-term results confirm the long-term efficacy of aneurysm clipping, when perfect. Small residual aneurysms can be followed with periodically performed angiography.


Turkish Neurosurgery | 2009

Effect of early bilateral decompressive craniectomy on outcome for severe traumatic brain injury.

Mahmut Akyuz; Tanju Uçar; Cem Açikbas; Saim Kazan; Murat Yilmaz; Recai Tuncer

AIM Debate continues as to whether decompressive craniectomy (DC) is an effective treatment for severe traumatic brain injury (STBI). DC is mostly used as a second tier treatment option. The aim of this study was determined whether early bilateral DC is effective as a first tier treatment option in patients with STBI. MATERIAL AND METHODS The study compared two groups. Group 1 comprised 36 STBI patients for whom control of intracranial pressure (ICP) was not achieved with conservative treatment methods according to radiological and neurological findings. These patients underwent bilateral or unilateral DC as a second tier treatment. Group 2 comprised 40 STBI patients who underwent early bilateral DC as a first tier treatment. RESULTS Group 2 patients had a mean better outcome than Group 1 patients especially for patients with a GCS 6-8. Postoperative ICP was lower in Group 2 patients than Group 1 patients. CONCLUSION This study indicates that early bilateral DC can be effective for controlling ICP in STBI patients. It is likely the favorable outcome results for Group 2 patients reflects the relatively short time between trauma and surgery. Therefore, these data indicate early bilateral DC can be considered as a first tier treatment in STBI patients.


Journal of Biomedical Optics | 2009

Intra-operative brain tumor detection using elastic light single-scattering spectroscopy: a feasibility study

Murat Canpolat; Mahmut Akyuz; Güzide Ayşe Gökhan; Elif Inanc Gurer; Recai Tuncer

We have investigated the potential application of elastic light single-scattering spectroscopy (ELSSS) as an adjunctive tool for intraoperative rapid detection of brain tumors and demarcation of the tumor from the surrounding normal tissue. Measurements were performed on 29 excised tumor specimens from 29 patients. There were 21 instances of low-grade tumors and eight instances of high-grade tumors. Normal gray matter and white matter brain tissue specimens of four epilepsy patients were used as a control group. One low-grade and one high-grade tumor were misclassified as normal brain tissue. Of the low- and high-grade tumors, 20 out of 21 and 7 out of 8 were correctly classified by the ELSSS system, respectively. One normal white matter tissue margin was detected in a high-grade tumor, and three normal tissue margins were detected in three low-grade tumors using spectroscopic data analysis and confirmed by histopathology. The spectral slopes were shown to be positive for normal white matter brain tissue and negative for normal gray matter and tumor tissues. Our results indicate that signs of spectral slopes may enable the discrimination of brain tumors from surrounding normal white matter brain tissue with a sensitivity of 93% and specificity of 100%.


Acta Neurochirurgica | 2004

Primary primitive neuro-ectodermal tumor of cauda equina with intracranial seeding.

Mahmut Akyuz; A. N. Demiral; Inanç Gürer; Tanju Uçar; Recai Tuncer

SummaryPrimitive neuro-ectodermal tumor (PNET) of the cauda equina is a rare entity. 18 cases have been reported in the literature so far, including 4 cases with intracranial seeding. Moreover parenchymal involvement of brain has never been reported as a form of intracranial seeding from PNET of the cauda equina. A 31 year-old female patient, with PNET of cauda equina showing intracranial seeding 6 months after surgery, is presented in this report. To our knowledge, this is the first adult case of spinal cord PNET with parenchymal involvement of brain. The histopathological, clinical and radiological findings as well as treatment of the patient were evaluated.


Neurocirugia | 2007

Bilateral abducens nerve palsy following ruptured anterior communicating artery aneurysm: report of 2 cases

Ethem Göksu; Mahmut Akyuz; D. Gürkanlar; Recai Tuncer

Isolated abducens nerve palsies associated with intracranial aneurysms have rarely been reported. Their association with anterior communicating artery (ACoA) is even rarer. Intracisternal clot formation and elevated intracranial pressure has been proposed to be the responsible mechanisms. Herewith, we report two cases of bilateral abducens palsies following ruptured ACoA aneurysms and speculated the possible mechanisms. Opening of Liliequists membrane provides clinical improvement due to CSF release.


Wiener Klinische Wochenschrift | 2006

Epithelioid hemangioendothelioma derived from the spine region: Case report and review of the literature

Güzide Ayşe Gökhan; Mahmut Akyuz; Inanç Gürer; Recai Tuncer

ZusammenfassungEpitheloide Hämangioendotheliome (EHE) sind seltene Gefäßtumore, die im Allgemeinen im Weichteilgewebe entstehen. Primäre Knochen EHEs, besonders solche im Wirbelsäulenbereich, sind sehr selten. Wir präsentieren den Fall eines 30-jährigen Mannes, der mit lumbalen Schmerzen, Gehproblemen, Harninkontinenz und einem tauben Gefühl in der kaudalen Region stationär aufgenommen wurde. Die Röntgenaufnahme zeigte einen lytischen Prozess am Wirbelkörper L2 und einen Kollaps des Wirbelkörpers L1. Es wurden eine operative Entfernung des Wirbels L1 und eine totale Resektion des Tumors durchgeführt. Die histopathologische und immunhistochemische Untersuchung des Tumorgewebes unterstützte die Diagnose des EHE. In dem vorliegenden Bericht wird der nach unserem Wissen fünfte Fall eines EHE in der Wirbelsäule mit allen klinisch-pathologischen Befunden in der Literatur präsentiert.SummaryEpithelioid hemangioendotheliomas (EHE) are rare vascular tumors which generally originate from soft tissues and visceral organs. Primary bone EHEs, especially those occurring in the spine region, are extremely rare. Our case is that of a 30-year-old man who was admitted to hospital with low back pain, difficulty in walking, post-voiding urinary incontinence and numbness in the caudal area. X-ray showed a lytic process affecting the vertebra L2 and collapse of L1. Vertebrectomy of L1 and gross total tumor resection were performed. Histopathological and immunohistochemical findings of the tumor tissue supported the diagnosis of EHE. The case, which to the best of our knowledge is only the fifth such reported case, is presented with its clinicopathological findings and a review of the literature.

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