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Öğe Anterior transpedicular screw fixation of cervical spine: Is it safe? Morphological feasibility, technical properties, and accuracy of manual insertion(AMER ASSOC NEUROLOGICAL SURGEONS, 2015) Koktekir, Ender; Toktas, Zafer Orkun; Seker, Askin; Akakin, Akin; Konya, Deniz; Kilic, TurkerOBJECT 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.Öğe The Effect of Bevacizumab on Spinal Epidural Fibrosis in a Postlaminectomy Rat Model(TURKISH NEUROSURGICAL SOC, 2012) Karatay, Mete; Erdem, Yavuz; Koktekir, Ender; Erkoc, Yavuz Seim; Caydere, Muzaffer; Bayar, Mehmet AkifAIM: Spinal epidural fibrosis is an inherent result of surgical trauma after laminectomy. The conditions in which epidural fibrosis is excessive are in the etiology of failed back syndrome. There have been many attempts to prevent formation of epidural fibrosis. Bevacizumab which is an anti-angiogenic medication, inhibits the effect of VEGF and thereby decreases the new blood vessel formation and as a result prevents adhesions. This study shows the effect of bevacizumab on spinal epidural fibrosis developing after laminectomy in rats. MATERIAL and METHODS: In this study, 20 Wistar rats were used. Rats were divided into two groups; a control group, and a bevacizumab group. Three-level laminectomy was performed on the rats. Rats in the control group only had the laminectomy. In the bevacizumab group, 2.5 mg/kg bevacizumab diluted in 0.9% NaCl with a factor of 1:10 impregnated on cotton was applied on the dura topically for 5 minutes. Three weeks later, rats were sacrificed for histopathologic examination. Epidural fibrosis tissue was graded following sacrifice. RESULTS: Statistically, it was found that the bevacizumab group had significantly less epidural fibrosis compared to the control group (p<0.05). CONCLUSION: Bevacizumab reduced the spinal epidural fibrosis significantly that developed in rats after laminectomy via its anti-VEGF effect by blocking VEGF receptors.Öğe The Effects of Electrocautery on Peripheral Nerve: An Experimental Study(THIEME MEDICAL PUBL INC, 2016) Karalezli, Nazim; Koktekir, Ender; Yildirim, Serhat; Toy, Hatice; Oz, Mehmet; Yuceturk, AydinBackground The aim of this study was to assess the usability of an electrocautery device as nerve stimulator and to investigate histopathologically the adverse effects of electrocautery at low power on rat sciatic nerves. Methods A total of 36 female Sprague-Dawley albino rats were divided into six groups according to the power applied to their sciatic nerves (1, 2, 3, 4, 5 and 6 W, respectively). Pathologic changes were studied by microscopic examination and scored (no change = 0, mild = 1, moderate = 2, severe = 3). Multiple comparisons were provided for all groups by the Bonferroni test (one-way analysis of variance). A p value < 0.05 was accepted as statistically significant. Results The average scores were 2.66 +/- 0.51, 3.66 +/- 0.51, 5.83 +/- 1.83, 10.0 +/- 1.78, 11.0 +/- 1.54, and 13.8 +/- 0.89 in groups 1 to 6, respectively. Significant differences were found between all groups (p < 0.01), except between groups 1 and 2, groups 2 and 3, and groups 4 and 5 (p > 0.05) Variable motor responses and foot deformities were observed at the different power levels. Conclusion Although electrocautery devices provoke motor responses if getting in contact with peripheral nerves as do nerve stimulators, their use induces histopathologically adverse effects even at the lowest power. Their use around peripheral nerves should be avoided.Öğe Intramedullary schwannoma of conus medullaris with syringomyelia(ELSEVIER SINGAPORE PTE LTD, 2017) Karatay, Mete; Koktekir, Ender; Erdem, Yavuz; Celik, Haydar; Sertbas, Idris; Bayar, Mehmet AkifIntramedullary schwannomas of the spinal cord are rare tumors. They are most commonly observed in the cervical region; however, few have been described in the conus medullaris. The association of intramedullary schwannomas with syringomyelia is also rare. In this report, we present a case of intramedullary schwannoma of the conus medullaris with syringomyelia, which was treated surgically. (C) 2017 Asian Surgical Association and Taiwan Robotic Surgical Association. Publishing services by Elsevier B.V.Öğe Intraorbital Epidermoid Cyst: A 5-Year-Old With Exophthalmos and Strabismus(Lippincott Williams & Wilkins, 2012) Ekinci, Bengu; Koktekir, Ender; Kal, Ali; Karalezli, Aylin; Erinanc, HilalA 5-year-old girl with right exophthalmos and esotropia presented to ophthalmology outpatient clinics. Orbital computed tomography revealed a 20-to 30-mm oval soft tissue mass lying superolateral to the right lateral rectus muscle in the orbit. The patient was operated on by a neurosurgical team, the csyt was removed totally, and examination of the pathologic specimen, which reveals the epidermoid cyst, was performed. After the operation, exophthalmos and esotropia were improved, and visual acuity was increased. Although itis seen as a rare entity in the orbit, epidermoid cyst must be considered during the investigation of exophthalmos.Öğe A Long Term Evaluation of Result of Surgically Treated Lower Cervical Spine Trauma of 83 Patients: A Retrospective Study(JOURNAL NEUROLOGICAL SCIENCES, 2013) Celik, Haydar; Koktekir, Ender; Karatay, Mete; Erdem, Yavuz; Gokcek, Cevdet; Yasitli, Ugur; Bayar, Mehmet AkifObjective: Retrospective evaluation of 83 patients who were surgically treated for lower cervical spine trauma. Materials and Methods: We retrospectively evaluated the 83 patients who operated because of lower cervical spine trauma in Ankara Training and Research Hospital Neurosurgery Clinic. All patients demographic data, type of trauma, cause of trauma, time of surgery, preoperative and postoperative neurologic grades were carefully evaluated. Only those who were closely followed up at least for 1 year, were included in the evaluation. The impact of surgical treatment on neurological status was assessed by using Frankel scale. Neurological improvement was assessed as mild, moderate and significant in respect to upgrade in Frankel scale in one step, two step and three or four step, respectively. Results: The number of male patients was 61 (73.5%) and the number of female patients was 22 (26.5%) The mean age was 45.1(+/-2,4). 49 patients had the other system injuries at the time of trauma. The most common cause of trauma was traffic accident (62,6%) and the most common mechanism was flexion injury (59%). The most common type of injury was dislocation (74,7%) and the C5 was the most frequently affected vertebra due to the trauma. 48 patients had various neurologic deficits at the time of admission (57,8%). Of these 48 patients 33 patients were surgically treated within the first 24 hours (68,75%) whereas 15 patients operated 24 hours later (31,25%). A total of 10 patients showed neurological improvement (12,04%). Although mild and moderate neurologic improvements were seen in patients who received early (<24 hours) or late (>24 hours) surgery, significant improvement was observed in patients who received surgery within 24 hours. The surgical approaches were anterior, posterior and combined in 73, 6 and 4 patients, respectively. Conclusion: Our study results indicate that the early surgical decompression and stabilization should be performed as soon as possible in patients with incomplete spinal cord injury. We also concluded that only anterior approach is an effective method in most patients who have cervical spinal trauma.Öğe Proptosis, Congestion, and Secondary Glaucoma Due to Carotid-Cavernous Fistula After Embolization(LIPPINCOTT WILLIAMS & WILKINS, 2011) Ekinci, Bengu; Koktekir, Ender; Kal, Ali; Karalezli, AylinCarotid-cavernous fistulas (CCFs) are traumatic or spontaneously occurring communications between the carotid artery and the cavernous sinus. Carotid-cavernous fistulas can be due to a direct connection or indirect connections between the carotid artery system and the cavernous sinus. According to the etiologic classification, they may be of traumatic or spontaneous origin, and according to the angiography classification, they may be of direct or dural. Most CCFs are of spontaneous origin, and these are reported as frequently self-healing lesions. Spontaneous CCFs are mostly secondary to arteriosclerotic changes, which explains the increased ratio of elderly patients. Traumatic CCFs are usually of high-flow type and need intervention. The symptoms are various usually correlated to the size and type of venous drainage. The most frequent symptoms on presentation are proptosis, conjunctivitis, and chemosis; however, this picture may be complicated by optic nerve edema, cranial nerve palsies, and intracranial hemorrhage. We report a case with right low-flow dural CCF, which has worsened after angiography and recovered totally soon after endovascular embolization process.Öğe Role of Tenoxicam in The Prevention of Postlaminectomy Peridural Fibrosis in Rats(2013) Karatay, Mete; Celik, Haydar; Koktekir, Ender; Karatay, Eylem; Sertbas, Idris; Yılmaz, Ali; Caydere, MuzafferAmaç: Spinal cerrahi sonrası peridural fibrozis bazı durumlarda başarısız bel sendromunun altında yatan neden olabilir. Peridural fibrozisin engellenmesi amacıyla bir çok materyal denenmiştir. Nonsteroidal anti-inflamatuar ilaçlar (NSAIDs) inflamatuar ve fibroblastik yanıtı engellerler. En etkili nonsteroidal anti-inflamatuar ilaçlardan biri olan tenoksicam bir oxicam türevidir. Bu çalışma tenoksicamın topikal uygulamasının ratlarda laminektomi sonrası gelişen spinal peridural fibrozisi önlemede etkili bir yol olduğunu göstermektedir. Yöntem ve Gereç: Bu çalışmada 20 adet Wistar cinsi rat kullanıldı. Kontrol ve tenoxicam olmak üzere ratlar 2 ayrı gruba ayrıldı. Ratlara 3 seviye laminektomi yapıldı. Kontrol grubuna sadece laminektomi yapıldı. Tenoxicam kullanılan gruba ise pamuğa emdirilmiş 0.5 mg/kg tenoxicam, 0.9% NaCl ile 1:10 sulandırılarak cerrahi alanda dura üzerine topikal olarak 5 dakika süre ile uygulandı. Üç hafta sonra, ratlar histopatolojik inceleme için öldürüldü ve peridural fibrozis dokusu sınıflandırıldı. Bulgular: Kontrol grubu ile karşılaştırıldığında ameliyat sonrası üçüncü hafta tenoxicam kullanılan grupta peridural fibrozisin istatiksel olarak anlamlı derecede azaldığı görüldü (p0,05). Sonuç: Tenoxicam laminektomi yapılmış ratlarda gelişen spinal peridural fibrozisi anlamlı derecede azaltmıştır.Öğe Role of Tenoxicam in The Prevention of Postlaminectomy Peridural Fibrosis in Rats(JOURNAL NEUROLOGICAL SCIENCES, 2013) Karatay, Mete; Celik, Haydar; Koktekir, Ender; Karatay, Eylem; Sertbas, Idris; Yilmaz, Ali; Caydere, MuzafferAim: The reason behind failed back syndrome in some cases may be peridural fibrosis following spinal surgery. Many attempts have been shown to stop formation of peridural fibrosis. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the inflammatory and fibroblastic response. One of the most effective nonsteroidal anti-inflammatory drugs is tenoxicam, an oxicam derivative. This study suggests that topical application of tenoxicam is an effective way of preventing spinal peridural fibrosis developing after laminectomy in rats. Material and Methods: In this study, 20 Wistar rats were used. Rats were divided into two groups; a control group, and a tenoxicam group. Three-level laminectomy was implemented on the rats. Rats in the control group only had the laminectomy. In the tenoxicam group, 0.5 mg/kg tenoxicam, which was watered down in 0.9% NaCl with a factor of 1:10 soaked on cotton, was applied on the dura topically for 5 minutes. Three weeks later, rats were killed for histopathologic examination and peridural fibrosis tissue was classified afterwards. Results: Statistically, it was found that three weeks after surgery, the tenoxicam group had significantly less peridural fibrosis compared to the control group (p<0.05). Conclusion: Tenoxicam significantly reduced the spinal peridural fibrosis that developed in rats after laminectomy.Öğe Simultaneous Transsphenoidal and Transventricular Endoscopic Approaches for Giant Pituitary Adenoma With Hydrocephalus(LIPPINCOTT WILLIAMS & WILKINS, 2015) Koktekir, Ender; Karabagli, Hakan; Ozturk, KayhanThe surgical management of giant pituitary adenomas is challenging. Although most pituitary adenomas, even those with suprasellar extension, can be resected using the transsphenoidal surgery alone, the transcranial approach is still needed for approximately 1% to 4% of these tumors. The transcranial approach is usually used in large adenomas with hourglass configuration and adenomas with firm consistency impeding the adjunctive measures, which are used for delivering the suprasellar part of the tumor into the sellar area and thereby obscure the tumor resection by transsphenoidal route. In this report, we describe the successful use of transventricular endoscope as an adjunctive measure to remove giant pituitary adenoma from transsphenoidal route and discuss the limitations of this new technique. We concluded that this technique would be used safely in selected cases. Case selection and surgical strategies should be based on preoperative magnetic resonance imaging findings, ventricular size, and the availability of experienced surgeons.Öğe Solitary Metastasis of Renal Cell Carcinoma to the Third Ventricle Mimicking a Colloid Cyst: Case Report(TURKISH NEUROSURGICAL SOC, 2015) Karatay, Mete; Koktekir, Ender; Erdem, Yavuz; Celik, Haydar; Bayar, Mehmet AkifColloid cysts are the most common third ventricle lesions and metastasis to this area is rare. We presented a case of solitary metastasis from a renal cell carcinoma to the third ventricle choroid plexus mimicking a colloid cyst. A 53-year-old man, who had a history of renal cell carcinoma 12 years ago, was operated for single third ventricle lesion and hydrocephalus via a transcallosal approach. Total removal could not be performed due to intraoperative massive bleeding. Histological examination revealed a metastatic renal cell carcinoma.The patient died on the postoperative 13th day because of bleeding from the residual tumor. Stereotactic radiosurgery and ventriculoperitoneal shunting might be favorable in such cases in order to avoid serious complications.Öğe An Unusual Mechanism of Delayed Intracerebral Hemorrhage After Ventriculoperitoneal Shunting: Case Report(Ege University Press, 2012) Koktekir, Ender; Tatarlı, Necati; Ceylan, Davut; Karabağlı, Hakan; Akdemir, GökhanWe present a case of delayed intracerebral hemorrhage that developed seven years after initial ventriculoperitoneal shunt surgery. A seven-year-old boy was admitted to emergency when he experienced sudden headache and vomiting. Computed tomography (CT) scanning showed an intracerebral hemorrhage around the ventricular catheter that cannot be explained by known predisposing factors such as head trauma, coexisting bleeding disorder, occult vascular malformation, and intratumoral hemorrhage. The presumed mechanism in this case is that the ventricular catheter caused contusion of cerebral tissue because the shunt tube at the neck had stretched during the growing up of the child.Öğe An Unusual Mechanism of Delayed Intracerebral Hemorrhage After Ventriculoperitoneal Shunting: Case Report(2012) Koktekir, Ender; Tatarli, Necati; Ceylan, Davut; Karabaglı, Hakan; Akdemir, GökhanBu olgu sunumunda ventriküloperitoneal şant cerrahisinden 7 yıl sonra geç gelişen bir intraserebral hemoraji olgusunu sunuyoruz. 7 yaşında erkek hasta acil servise ani başlayan baş ağrısı ve kusma şikayetleri ile başvurdu. Bilgisayarlı beyin tomografi incelemesi,ventriküler katater etrafında intraserebral hemoraji varlığını gösteriyordu. Hastanın öyküsü,labaratuvar bulguları ve radyolojik incelemelerinde intraserebral hemorajiye neden olabilecek kafa travması, kanama diyatezi, vasküler malformasyon ve intratümoral hemoraji saptanmadı. Bu vakada intraserebral hemorajiye yol açan tahmini mekanizma, çocuğun büyüme döneminde boyun bölgesinde gerilmiş olan şant tüpü nedeni ile ventriküler kataterin gerilmesi ile oluşan serebral dokunun kontüzyonuydu.Öğe Vascular Silicone Injection of Fresh Cadaveric Cow Cranium: Alternative Training Model For The Human Brain(JOURNAL NEUROLOGICAL SCIENCES, 2015) Tatarli, Necati; Suslu, Hikmet Turan; Ceylan, Davut; Seker, Askin; Karabagli, Hakan; Koktekir, Ender; Ozdogan, SelcukBackground: Anatomical and physiological variations of the human brain's vascular system can be observed via silicone injection of the arterial and venous systems. As a novel method, the injection of a fresh cadaveric cow cranium with silicone is an alternative to using the human brain for microanatomical studies. Objective: To report on an improved method for the colored silicone injection of a fresh cadaveric cow cranium using a silicone injection technique. Methods: Five fresh cow crania were injected as an alternative to human brains for microanatomical dissection, in which the preparation consisted of the irrigation of the major vessels and the injection of colored silicone. Cannulation of the internal carotid arteries and the internal jugular veins with catheters was performed, and the vasculature was irrigated with water (major arteries and veins). The fixation of the specimen with either formaldehyde or alcohol, and the colored injection of the arteries and veins with red and blue silicone, respectively, was then performed. Results: The silicone injections resulted in the deeper penetration of the colored solutions into the small cerebral vessels and mesenchymal structures of the fresh cadaveric cow crania. Of the five injected specimens, four exhibited successful injections, while one had suboptimal results. Conclusion: Silicone injection of the cadaveric cow brain, based on the anatomical and physiological assessment of the vasculature of the specimen for microanatomical studies, is suggested as an alternative to using human brain specimens.
