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Papers by Ahmet Kayhan

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of The Synergistic Effect of Combined Transforaminal and Caudal Epidural Steroid Injection in Recurrent Lumbar Disc Herniations

Research paper thumbnail of Assessing the connectional anatomy of superior and lateral surgical approaches for medial temporal lobe epilepsy

Journal of Clinical Neuroscience

Research paper thumbnail of Multi-level anterior cervical decompression in multi-level cervical spondylotic myelopathy without extending the corpus resection: a cadaveric study of a novel surgical technique

Research paper thumbnail of The Expression of MIR17HG Protein as a Potential Therapeutic Target in Meningioma

Research paper thumbnail of Can preoperative neutrophil to lymphocyte, lymphocyte to monocyte, or platelet to lymphocyte ratios differentiate glioblastoma from brain metastasis?

Research paper thumbnail of Preoperative systemic inflammatory markers in different brain pathologies: an analysis of 140 patients

Research paper thumbnail of Serum Endocan and Preoperative Systemic Inflammatory Markers in Patients with Epilepsy

Research paper thumbnail of An Exceptional Neurosurgical Presentation of a Patient with Osteopetrosis

World neurosurgery, 2018

Osteopetrosis (OP) is a varied clinical condition caused by malfunction or insufficient developme... more Osteopetrosis (OP) is a varied clinical condition caused by malfunction or insufficient development of osteoclasts, or both. Neurologic findings can occur because of osteopetrotic conditions restricting neural foramina through which the spinal cord, cranial nerves, or major vascular structures traverse the skull. Renal tubular acidosis (RTA) is a well-documented condition with OP. However, Chiari I malformation is rarely reported concomitantly with OP. We present a patient with a known RTA who was admitted with a rapid progressive tetraparesis within 24 hours. Clinical and radiologic evaluation of the patient revealed OP with RTA together with Chiari I malformation and holocord hydromyelia. Management of the patient was started with correction of severe hypokalemia (K: 1.4 mEq/L), which resulted in dramatic improvement in tetraparesis. Two days later, a posterior fossa bone decompression with ventriculoperitoneal shunt placement during the same session led to prominent decrease in s...

Research paper thumbnail of Surgical Management of Sphenoid Sinus Lateral Recess Cerebrospinal Fluid Leaks: A Single Neurosurgical Center Analysis of Endoscopic Endonasal Minimal Transpterygoid Approach

World neurosurgery, 2018

To review the results of sphenoid sinus lateral recess (SSLR) cerebrospinal fluid (CSF) leaks tre... more To review the results of sphenoid sinus lateral recess (SSLR) cerebrospinal fluid (CSF) leaks treated with the endoscopic endonasal minimal transpterygoid approach (EEMTPA) and to discuss the surgical technique and outcomes. We performed a retrospective analysis of 13 cases who underwent SSLR CSF leak repair through the EEMTPA in our clinic between September 2008 and December 2017. Demographic and etiological features with reconstruction and surgical outcomes were examined. Mean follow-up time was 6.1 years. In regard to etiology, the SSLR CSF leaks included 9 patients with spontaneous, 2 patients with traumatic, and 2 with iatrogenic causes. CSF leak was at the left lateral recess in 8 cases and at right lateral recess in 5 cases. Nine patients had empty sella syndrome, and 11 patients had meningoencephaloceles in addition to SSLR CSF leaks. All patients underwent surgery through the EEMTPA, and a multilayer closure with tissue overlay grafts were used for reconstruction. A pedicle...

Research paper thumbnail of Seizure Outcome of Patients with Magnetic Resonance Imaging-Negative Epilepsies: Still An Ongoing Debate

World neurosurgery, Jan 19, 2017

Surgical results regarding MRI-negative epilepsy were presented and related clinical and histopat... more Surgical results regarding MRI-negative epilepsy were presented and related clinical and histopathological parameters were discussed. Thirty-six MRI-negative epilepsy patients were retrospectively analyzed. Histopathological specimens were re-reviewed by 2 blind neuropathologists and re-classified based on the current classifications. The mean age at surgery and seizure onset was 24.5 years and 9.3 years, respectively. Eight patients were younger than 18 years. Mean duration of seizures was 15.3 years. All but 2 underwent invasive monitorization. Eighteen patients had hypometabolism on FDG-PET with temporal lobe involvement in majority (66.7%). Hypometabolism was found in all patients with hippocampal sclerosis (HS), which was present in 50% and 66.7% of focal cortical dysplasia (FCD) type I and II patients, respectively. The frontal lobe resection was the most frequent type of operation followed by resections in temporal, parietal and occipital lobes. In 7 patients, multilobar rese...

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Neurosurgery Intensive Care Unit Infections; Single Center Retrospective Study

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of The Synergistic Effect of Combined Transforaminal and Caudal Epidural Steroid Injection in Recurrent Lumbar Disc Herniations

Research paper thumbnail of Assessing the connectional anatomy of superior and lateral surgical approaches for medial temporal lobe epilepsy

Journal of Clinical Neuroscience

Research paper thumbnail of Multi-level anterior cervical decompression in multi-level cervical spondylotic myelopathy without extending the corpus resection: a cadaveric study of a novel surgical technique

Research paper thumbnail of The Expression of MIR17HG Protein as a Potential Therapeutic Target in Meningioma

Research paper thumbnail of Can preoperative neutrophil to lymphocyte, lymphocyte to monocyte, or platelet to lymphocyte ratios differentiate glioblastoma from brain metastasis?

Research paper thumbnail of Preoperative systemic inflammatory markers in different brain pathologies: an analysis of 140 patients

Research paper thumbnail of Serum Endocan and Preoperative Systemic Inflammatory Markers in Patients with Epilepsy

Research paper thumbnail of An Exceptional Neurosurgical Presentation of a Patient with Osteopetrosis

World neurosurgery, 2018

Osteopetrosis (OP) is a varied clinical condition caused by malfunction or insufficient developme... more Osteopetrosis (OP) is a varied clinical condition caused by malfunction or insufficient development of osteoclasts, or both. Neurologic findings can occur because of osteopetrotic conditions restricting neural foramina through which the spinal cord, cranial nerves, or major vascular structures traverse the skull. Renal tubular acidosis (RTA) is a well-documented condition with OP. However, Chiari I malformation is rarely reported concomitantly with OP. We present a patient with a known RTA who was admitted with a rapid progressive tetraparesis within 24 hours. Clinical and radiologic evaluation of the patient revealed OP with RTA together with Chiari I malformation and holocord hydromyelia. Management of the patient was started with correction of severe hypokalemia (K: 1.4 mEq/L), which resulted in dramatic improvement in tetraparesis. Two days later, a posterior fossa bone decompression with ventriculoperitoneal shunt placement during the same session led to prominent decrease in s...

Research paper thumbnail of Surgical Management of Sphenoid Sinus Lateral Recess Cerebrospinal Fluid Leaks: A Single Neurosurgical Center Analysis of Endoscopic Endonasal Minimal Transpterygoid Approach

World neurosurgery, 2018

To review the results of sphenoid sinus lateral recess (SSLR) cerebrospinal fluid (CSF) leaks tre... more To review the results of sphenoid sinus lateral recess (SSLR) cerebrospinal fluid (CSF) leaks treated with the endoscopic endonasal minimal transpterygoid approach (EEMTPA) and to discuss the surgical technique and outcomes. We performed a retrospective analysis of 13 cases who underwent SSLR CSF leak repair through the EEMTPA in our clinic between September 2008 and December 2017. Demographic and etiological features with reconstruction and surgical outcomes were examined. Mean follow-up time was 6.1 years. In regard to etiology, the SSLR CSF leaks included 9 patients with spontaneous, 2 patients with traumatic, and 2 with iatrogenic causes. CSF leak was at the left lateral recess in 8 cases and at right lateral recess in 5 cases. Nine patients had empty sella syndrome, and 11 patients had meningoencephaloceles in addition to SSLR CSF leaks. All patients underwent surgery through the EEMTPA, and a multilayer closure with tissue overlay grafts were used for reconstruction. A pedicle...

Research paper thumbnail of Seizure Outcome of Patients with Magnetic Resonance Imaging-Negative Epilepsies: Still An Ongoing Debate

World neurosurgery, Jan 19, 2017

Surgical results regarding MRI-negative epilepsy were presented and related clinical and histopat... more Surgical results regarding MRI-negative epilepsy were presented and related clinical and histopathological parameters were discussed. Thirty-six MRI-negative epilepsy patients were retrospectively analyzed. Histopathological specimens were re-reviewed by 2 blind neuropathologists and re-classified based on the current classifications. The mean age at surgery and seizure onset was 24.5 years and 9.3 years, respectively. Eight patients were younger than 18 years. Mean duration of seizures was 15.3 years. All but 2 underwent invasive monitorization. Eighteen patients had hypometabolism on FDG-PET with temporal lobe involvement in majority (66.7%). Hypometabolism was found in all patients with hippocampal sclerosis (HS), which was present in 50% and 66.7% of focal cortical dysplasia (FCD) type I and II patients, respectively. The frontal lobe resection was the most frequent type of operation followed by resections in temporal, parietal and occipital lobes. In 7 patients, multilobar rese...

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Cervical Cord Injury With Sharp Device: A Case Report

İstanbul Kanuni Sultan Süleyman Tıp Dergisi, 2015

Research paper thumbnail of Neurosurgery Intensive Care Unit Infections; Single Center Retrospective Study

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