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Publication Open Access Rare and challenging extra-axial brain lesions: CT and MRI fndings with clinico-radiological differential diagnosis and pathological correlation(AVES Ibrahim Kara [email protected] 105/9 Buyukdere Cad Mecidiyekoy,Sisli, Istanbul 34394, 2014) Demir, Mustafa Kemal; Kurtkaya-Yapıcıer, Özlem Sahan; Onat, Elif; Toktaş, Zafer Orkun; Akakın, Akın; Urgun, Kamran; Kılıç, Türker; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kurtkaya-Yapicier, Özlem Sahan, Department of Pathology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Onat, Elif, Department of Pathology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Urgun, Kamran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyThere are many kinds of extra-axial brain tumors and tumor-like lesions, and definitive diagnosis is complicated in some cases. In this pictorial essay, we present rare and challenging extra-axial brain lesions including neuroenteric cyst, primary leptomeningeal melanomatosis, isolated du-ral neurosarcoidosis, intradiploic epidermoid cyst, ruptured dermoid cyst, intraventricular cavernoma, and cavernous hemangioma of the skull with imaging findings and clini-co-radiological differential diagnosis, including the pathologic correlation. Familiarity with these entities may improve diagnostic accuracy and patient management. © Turkish Society of Radiology 2014. © 2014 Elsevier B.V., All rights reserved.Publication Metadata only Locally aggressive de novo spinal fibromatosis: Case report and review of the literature(Turkish Neurosurgical Society [email protected], 2015) Ekşi̇, Murat Şakir; Türköz, Hüseyin Kemal; Özcan-Ekşi̇, Emel Ece; Akakın, Akın; Toktaş, Zafer Orkun; Konya, Deniz; Ekşi̇, Murat Şakir, UCSF School of Medicine, San Francisco, United States; Türköz, Hüseyin Kemal, Department of Pathology, Marmara Üniversitesi, Istanbul, Turkey; Özcan-Ekşi̇, Emel Ece, UCSF School of Medicine, San Francisco, United States; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyFibromatosis is a benign lesion, which originates from proliferating fibroblasts. Although fibromatosis is a benign tumor, it is locally aggressive and invasive. Spinal presentation of fibromatosis is very rare, and case reports are the only source of the clinical knowledge. Herein, we describe the oldest patient having spinal fibromatosis with de novo occurrence and aggressive nature. A 68-year-old female patient admitted to our outpatient clinic with low back pain and neurological claudication. On lumbar spine magnetic resonance imaging, she had spinal canal stenosis with a concomitant lesion in the left longissimus muscle. We did our best to resect the tumor, entirely. The pathology result was consistent with spindle cell lesion. The lesion recurred 6 months after the primary surgery. In the second surgery, we did en bloc resection. Pathology and immunohistochemical analysis results were consistent with fibromatosis. After the second surgery, she had adjuvant radiotherapy. There was nothing other than radionecrosis in the operation site, still after 2 years. In conclusion, radiological work-up is usually insufficient to make fibromatosis diagnosis and whole pathological specimen should be carefully evaluated to achieve the accurate diagnosis. Spinal fibromatosis is very rare and its treatment methods have not universally been conceptualized. However, adjuvant therapies are necessary after en bloc resection. © 2017 Elsevier B.V., All rights reserved.Publication Open Access Biological approaches to treating intervertebral disk degeneration: Devising stem cell therapies(Cognizant Communication Corporation [email protected] 3 Hartsdale Road Elmsford NY 10523-3701, 2015) Han, Inbo; Ropper, Alexander Eli; Konya, Deniz; Kabataş, Serdar; Toktaş, Zafer Orkun; Aljuboori, Zaid S.; Zeng, Xiang; Chi, John H.; Zafonte, Ross D.; Teng, Yang D.; Han, Inbo, Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States, Department of Neurosurgery, College of Medicine, Pochon CHA University, Pocheon, South Korea; Ropper, Alexander Eli, Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States, Department of Neurosurgery, Barrow Neurological Institute, Phoenix, United States; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kabatas, Serdar, Department of Neurosurgery, Reyap Hospital, Tekirdag, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Aljuboori, Zaid S., Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States, University of Louisville School of Medicine, Louisville, United States; Zeng, Xiang, Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States, Department of Neurosurgery, College of Medicine, Pochon CHA University, Pocheon, South Korea; Chi, John H., Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States; Zafonte, Ross D., Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Boston, United States; Teng, Yang D., Department of Neurosurgery, Brigham and Women's Hospital, Boston, United States, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital Network, Boston, United States, Division of SCI Research, VA Medical Center, United StatesIntervertebral disk (IVD) degeneration is a common, chronic, and complex degeneration process that frequently leads to back pain and disability, resulting in a major public health issue. In this review we describe biological therapies under preclinical or clinical development with an emphasis on stem cell-based multimodal approaches that target prevention and treatment of IVD degeneration. Systematical review of the basic science and clinical literature was performed to summarize the current status of devising biological approaches to treating IVD degeneration. Since the exact mechanisms underlying IVD degeneration have not yet been fully elucidated and conservative managements appear to be mostly ineffective, current surgical treatment focuses on removal of the pathological disk tissues combined with spinal fusion. The treatment options, however, often produce insufficient efficacy and even serious complications. Therefore, there have been growing demands and endeavors for developing novel regenerative biology-guided strategies for repairing the IVD via delivery of exogenous growth factors, introduction of therapeutic genes, and transplantation of stem cells, or combinatorial therapies. Overall, the data suggest that when applied under a recovery neurobiology principle, multimodal regimens comprising ex vivo engineered stem cell-based disks hold a high potential promise for efficacious clinical translations. © 2017 Elsevier B.V., All rights reserved.Publication Metadata only Anterior transpedicular screw fixation of cervical spine: Is it safe? Morphological feasibility, technical properties, and accuracy of manual insertion(American Association of Neurological Surgeons, 2015) Köktekir, Ender; Toktaş, Zafer Orkun; Şeker, Aśkin N.; Akakin, Akin In; Konya, Deniz; Kilic, Turker D.; Köktekir, Ender, Department of Neurosurgery, Selçuk Üniversitesi, Selçuklu, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Şeker, Aśkin N., Department of Neurosurgery, Marmara Üniversitesi, Istanbul, Turkey; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyOBJECT: Due to lack of construct stability of the current anterior cervical approaches, supplemental posterior cervical approaches are frequently employed. The use of an anterior-only approach with anterior transpedicular screws (ATPSs) has been proposed as a means of providing 3-column fixation. This study was designed to investigate the feasibility of anterior transpedicular screw (ATPS) fixation of cervical spine, to obtain the morphological measurements for technical prerequisites, and to evaluate the accuracy of the ATPS using fluoroscopy. METHODS: The study included both radiological and anatomical investigations. The radiological investigations were based on data from cervical spine CT scans performed in 65 patients. Technical prerequisites of ATPS were calculated using OsiriX for Mac OS. In the anatomical part of the study, 30 pedicles (C3-7) from 6 formalin-preserved cadavers were manually instrumented. Measurements obtained included pedicle width (PW), pedicle height (PH), pedicle transverse angle (PTA), distance of the entry point from the midline (DEPM), and distance of the entry point from the superior endplate (DEPSEP). The authors also analyzed screw position in the manually instrumented vertebrae. RESULTS: The mean PW and PH values showed a tendency to increase from C-3 to C-7 in both males and females. The means were significantly larger for both PW and PH in males than in females at all levels (p = 0.001). The overall mean PTA value was significantly lower at C-7 (p < 0.0001). The mean value for the distance of entry point from the midline (DEPM) represented a point at the contralateral side of the pedicle for every level except C-7. The mean DEPSEP values showed significant differences between all levels (p < 0.0001). Seven of the 30 screws were identified as breaching the pedicle (23.3%), these screw malplacements were seen at C-3 (3 screws), C-4 (2 screws), and C-5 (2 screws). CONCLUSIONS: The morphological measurements of this study demonstrated that ATPS fixation is feasible in selected cases. They indicate that ATPS insertion using a fluoroscopy-assisted pedicle axis view is safe at the C-6 and C-7 levels, but the results at the other levels did not prove the safety of this technique. © 2018 Elsevier B.V., All rights reserved.Publication Metadata only Kyphectomy and Pedicular Screw Fixation with Posterior-Only Approach in Pediatric Patients with Myelomeningocele(S. Karger AG, 2015) Kaplan, Sümeyye Çoruh; Ekşi̇, Murat Şakir; Bayri, Yasar; Toktaş, Zafer Orkun; Konya, Deniz; Kaplan, Sümeyye Çoruh, Department of Neurosurgery, Bismil Devlet Hastanesi, Diyarbakir, Turkey; Ekşi̇, Murat Şakir, UCSF School of Medicine, San Francisco, United States; Bayri, Yasar, Department of Neurosurgery, Marmara Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyPurpose: Defective posterior spinal arch and paraspinal musculature lead to progressive kyphosis in patients with myelomeningocele. Kyphosis decreases the patients' functional status and quality of life. To correct or prevent further deterioration, different surgical techniques have been introduced. Our aim is to present our clinical experience in kyphectomy and pedicle screw fixation with a posterior-only approach in pediatric patients with myelomeningocele and to discuss the technique with a review of the literature. Materials and Methods: Four patients with lumbar and 2 patients with thoracolumbar kyphosis (female:male ratio = 1:5) secondary to myelomeningocele were operated between January 2009 and October 2012. The median age was 5.5 years (range = 3-10 years). The criteria of the patient selection for the procedure were progression of kyphosis angle, impaired truncal balance and cosmetic deformity. In this retrospective study, we performed chart reviews for demographic and clinical data. We measured the pre- and postoperative kyphosis angles by using the Cobb method on lateral x-rays. Results: The mean preoperative kyphosis angle was 114.3° (range = 91-136°). The mean operative time was 171.7 min (range = 110-220 min). The mean intraoperative blood loss was 450 cc (range = 300-700 cc). The postoperative mean kyphosis angle was 28.2° (range = 13-33°). Five patients had skin breakdown. After osteofusion was established, those 5 patients' instrumentations were explanted. No acute or immediate postoperative complications occurred. Other complications were pneumonia and urinary tract infection. In the long term, 2 patients died due to pneumonia and slit-ventricle syndrome, respectively. Conclusions: Kyphectomy and pedicle screw instrumentation with the posterior-only approach dramatically reduces the kyphosis angle that develops in patients with myelomeningocele. The method itself is less time-consuming and leads to less intraoperative blood loss compared to other methods used for this patient population. Skin breakdown is the most common short-term complication. © 2016 Elsevier B.V., All rights reserved.Publication Metadata only Association of collagen I, IX and vitamin D receptor gene polymorphisms with radiological severity of intervertebral disc degeneration in Southern European Ancestor(Springer Verlag [email protected], 2015) Toktaş, Zafer Orkun; Ekşi̇, Murat Şakir; Yilmaz, Baran; Demir, Mustafa Kemal; Özgen, Serdar; Kilic, Turker D.; Konya, Deniz; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Ekşi̇, Murat Şakir, UCSF School of Medicine, San Francisco, United States; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Özgen, Serdar, Department of Neurosurgery, Acıbadem Mehmet Ali Aydınlar Üniversitesi, Istanbul, Turkey; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyPurpose: Several genomic loci have been previously found to be associated with intervertebral disc degeneration, so far. Data are mostly derived from northern European countries whereas data derived from Southern European Ancestor are limited. This study aimed to evaluate the association between radiological disease severity of lumbar disc degeneration and certain genetic loci in a sample of participants from Southern Europe. Methods: Seventy-five patients with mild to severe lumbar disc degeneration and 25 healthy controls were enrolled into the study. In each subject, each lumbar intervertebral disc was separately examined to obtain a total radiological score for disease severity. In addition, single-nucleotide polymorphisms of predefined genetic samples were analyzed in all participants: COL1A1 Sp1, COL9a2 Trp2, COL9a3 Trp3, and VDR TaqI. Results: Degeneration scores were significantly worse in cases with COL1A1 Sp1, COL9a3 Trp3, and VDR TaqI mutations, however, COL9a2 Trp2 mutation was not associated with a difference in the severity of disc degeneration. In addition, subjects with mutation in more than one gene sample (n = 20) had significantly worse degeneration scores than the remaining study participants (n = 80) (17.70 ± 2.72 vs. 21.81 ± 1.81, p < 0.001). Conclusion: Single-nucleotide polymorphisms occurring in COL1A1, COL9a3 and VDR genes seem to be associated with the development of lumbar disc degeneration in this cohort, possibly with even more pronounced association when multiple mutations are present in the same individual. By further prospective twin studies in associated genes and analyses of their relationship with environmental factors in an internationally sampled large cohort will make a more clear-minded conclusion about their association with disc degeneration, which would yield better appreciation and clinical planning of some predisposed people for these pathologies. © 2016 Elsevier B.V., All rights reserved.Publication Metadata only Immature ganglioneuroma of the thoracic spine with lipomatous component: A rare cause of scoliosis(Elsevier Inc. [email protected], 2015) Demir, Mustafa Kemal; Kurtkaya-Yapicier, Özlem Sahan; Toktaş, Zafer Orkun; Yilmaz, Baran; Konya, Deniz; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kurtkaya-Yapicier, Özlem Sahan, Department of Pathology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey[No abstract available]Publication Metadata only Gamma Knife treatment of low-grade gliomas in children(Springer Verlag [email protected], 2015) Ekşi̇, Murat Şakir; Yilmaz, Baran; Akakin, Akin In; Toktaş, Zafer Orkun; Kaur, Ahmet Cemil; Demir, Mustafa Kemal; Kilic, Turker D.; Ekşi̇, Murat Şakir, University of California, San Francisco, San Francisco, United States; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kaur, Ahmet Cemil, Department of Pathology, Medical Park Göztepe Hospital, Istanbul, Turkey; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyBackground: Low-grade gliomas have good overall survival rates in pediatric patients compared to adults. There are some case series that reported the effectiveness and safety of Gamma Knife radiosurgery, yet they are limited in number of patients. We aimed to review the relevant literature for pediatric low-grade glial tumors treated with stereotactic radiosurgery, specifically Gamma Knife radiosurgery, and to present an exemplary case. Case description: A 6-year-old boy was admitted to clinic due to head trauma. He was alert, cooperative, and had no obvious motor or sensorial deficit. A head CT scan depicted a hypodense zone at the right caudate nucleus. The brain magnetic resonance imaging (MRI) depicted a mass lesion at the same location. A stereotactic biopsy was performed. Histopathological diagnosis was low-grade astrocytoma (grade II, World Health Organization (WHO) classification, 2007). Gamma Knife radiosurgery was applied to the tumor bed. Tumor volume was 21.85 cm3. Fourteen gray was given to 50 % isodose segment of the lesion (maximal dose of 28 Gy). The tumor has disappeared totally in 4 months, and the patient was tumor-free 21 months after the initial treatment. Discussion and conclusion: The presented literature review represents mostly single-center experiences with different patient and treatment characteristics. Accordingly, a mean/median margin dose of 11.3–15 Gy with Gamma Knife radiosurgery (GKRS) is successful in treatment of pediatric and adult low-grade glial tumor patients. However, prospective studies with a large cohort of pediatric patients should be conducted to make a more comprehensive conclusion for effectiveness and safety of GKRS in pediatric low-grade glial tumors. © 2015 Elsevier B.V., All rights reserved.Publication Metadata only Lumbar Spinal Immature Ganglioneuroma with Conus Medullaris Invasion: Case Report(S. Karger AG, 2015) Yilmaz, Baran; Toktaş, Zafer Orkun; Akakln, Akln; Demir, Mustafa Kemal; Kurtkaya-Yapicier, Özlem Sahan; Konya, Deniz; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akakln, Akln, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kurtkaya-Yapicier, Özlem Sahan, Department of Pathology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyGanglioneuroma (GN) is a benign rare tumor that originates from neural crest cells. It shares a common histogenic family with ganglioneuroblastoma and neuroblastoma and represents the most benign and differentiated form of the group. The most common locations of the GNs are the mediastinum and retroperitoneum. We report an extremely rare case of lumbar spinal GN with conus medullaris invasion and extradural paraspinal extension. A 10-year-old girl presented with a history of worsening lower-back pain and an intermittent tingling sensation in the left leg. Neurological examination revealed reduced sensation in the left L2-L5 dermatomes. Magnetic resonance imaging revealed an intra- and extradural mass extending from the D11 to L5 vertebral body level. There was conus medullaris invasion by the tumor. After L1-L5 laminotomies, the patient underwent tumor resection. Histopathological diagnosis was immature GN. GNs occurring within the spinal column are rare and may grow to a large size. Despite the size and the common involvement of both intra- and extraspinal compartments, the prognosis is usually excellent after complete excision using microsurgical techniques. © 2016 Elsevier B.V., All rights reserved.Publication Metadata only Gorham's disease - Vanishing bone of the cervical spine(Elsevier Inc. [email protected], 2016) Demir, Mustafa Kemal; Kurtkaya-Yapicier, Özlem Sahan; Toktaş, Zafer Orkun; Yilmaz, Baran; Akakin, Akin In; Konya, Deniz; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kurtkaya-Yapicier, Özlem Sahan, Department of Pathology, Acıbadem Mehmet Ali Aydınlar Üniversitesi, Istanbul, Turkey; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey[No abstract available]