Researcher: Çavdar, Safiye
Loading...
Name Variants
Çavdar, Safiye
Email Address
Birth Date
43 results
Search Results
Now showing 1 - 10 of 43
Publication Metadata only Response to microsurgical anatomy of lumbosacral spinal roots(Springer, 2015) Çavdar, Safiye; Faculty Member; School of Medicine; 1995Publication Metadata only Surgical exposure gained in an extended retrosigmoid approach to the cerebellopontine angle compared to the traditional retrosigmoid approach(Turkish Neurosurgery Society, 2015) Ceylan, Davut; Tatarlı, Necati; Şeker, Aşkın; Kılıç, Türker; Çavdar, Safiye; Faculty Member; School of Medicine; 1995Aim: Retrosigmoid approach to the posterior fossa has been a popular and dependable approach for accessing the cerebellopontine angle (CPA) and petroclival region. Although this approach is commonly used, it requires cerebellar retraction and has limitations when the lesion is located ventral to the brainstem. The aim was to quantify the angle of view provided by extended retrosigmoid approach in comparison to the traditional approach. A secondary objective was to identify a strategic initial burr hole site for craniotomy. MaterIal and Methods: Ten adult human cadaver heads (20 sides) were used. First, traditional retrosigmoid approach was performed and the angle of exposure was measured on cranial computerized tomography (CT). Following, extended retrosigmoid approach was performed with mastoid bone drilling and reflection of venous sinuses. Angle of exposure was measured on CT. Two measurements of both approaches were compared. Results: Mean angle of view for the traditional retrosigmoid approach (31.4°±4.1°) was significantly smaller than that of the extended approach (46.0°±4.7°) (p< 0.001). Site of strategic burr hole was 5 mm below and 15 mm lateral to the asterion was defined. ConclusIon: Extended retrosigmoid approach offers neurosurgeons approximately 50% larger angle of view and shorter working distance than the traditional approach provides. This modification permits better access to the CPA and ventral brain stem without cerebellar retraction. / AMAÇ: Serebellopontin köşe ve petroklival alana ulaşım için retrosigmoid yaklaşım yaygın kullanılan ve güvenilir bir yöntemdir. Ancak bu yaklaşımda, özelliklede lezyonun beyin sapının ventralinde olduğu durumlarda serebellar retraksiyon gerektiğinden, yöntemin kısıtlamaları bulunmaktadır. Çalışmada amaç, genişletilmiş retrosigmoid (ERS) yaklaşımla kazanılan görüş açısının miktarının belirlenmesi ve geleneksel yöntemle (TRS) karşılaştırılmasıdır. İkincil amaç ise, bu yaklaşım için stratejik burr hole yerinin tespit edilmesidir. YÖNTEM ve GEREÇLER: on yetişkin insan kadavra kafası (20 bölge) kullanıldı. Önce TRS yaklaşımı uygulanarak elde edilen görüş açısı kranial BT kullanılarak ölçüldü. Daha sonra mastoid kemiğin drillenmesi ve venöz sinüslerin refleksiyonu ile ERS yaklaşımı uygulandı. Aynı ölçümler bu yöntemde de elde edildi. İki yaklaşımın ölçümleri karşılaştırıldı. BULGULAR: Geleneksel yaklaşımla elde edilen görüş açısı ortalaması (31,4°±4,1°), genişletilmiş yaklaşımla elde edilen değerden (46,0°±4,7°) istatiksel olarak anlamlı düzeyde düşük bulundu (p< 0,001). Stratejik burr hole alanı olarak asterionun 5 mm altı ve 15 mm laterali belirlendi. SONUÇ: ERS yaklaşımı, TRS yaklaşımına göre yaklaşık olarak %50 daha fazla görüş açısı kazandırmaktadır. Bu modifikasyon serebellar retraksiyon yapmadan CPA ve beyin sapının ventraline daha iyi ulaşım olanağı sağlamaktadır.Publication Metadata only The cerebello-hypothalamic and hypothalamo-cerebellar pathways via superior and middle cerebellar peduncle in the rat(Springer, 2018) Bay, Hüsniye Hacıoğlu; Çavdar, Safiye; Özgür, Merve; Kuvvet, Yasemin; Faculty Member; PhD Student; PhD Student; School of Medicine; Graduate School of Health Sciences; Graduate School of Health Sciences; 1995; N/A; N/AThe connections between the cerebellum and the hypothalamus have been well documented. However, the specific cerebellar peduncle through which the hypothalamo-cerebellar and cerebello-hypothalamic connections pass has not been demonstrated. The present study aims to define the specific cerebellar peduncle through which connects the cerebellum to specific hypothalamic nuclei. Seventeen male albino rats received 20-50-nl pressure injections of either Fluoro-Gold (FG) or biotinylated dextran amine (BDA) tracer into the superior (SCP), middle (MCP), and inferior (ICP) cerebellar peduncle. Following 7-10days of survival period, the animals were processed according to the appropriate protocol for the two tracers used. Labeled cells and axons were documented using light or fluorescence microscopy. The present study showed connections between the hypothalamus and the cerebellum via both the SCP and the MCP but not the ICP. The hypothalamo-cerebellar connections via the SCP were from the lateral, dorsomedial, paraventricular, and posterior hypothalamic nuclei, and cerebello-hypothalamic connections were to the preoptic and lateral hypothalamic nuclei. The hypothalamo-cerebellar connections via the MCP were from the lateral, dorsomedial, ventromedial, and mammillary hypothalamic nuclei; and cerebello-hypothalamic connections were to the posterior, arcuate, and ventromedial hypothalamic nuclei. The hypothlamo-cerebellar connections were denser compared to the cerebello-hypothlamic connections via both the SCP and the MCP. The connection between the cerebellum and the hypothalamus was more prominent via the SCP than MCP. Both the hypothlamo-cerebellar and cerebello-hypothalamic connections were bilateral, with ipsilateral prepÖnderance. Reciprocal connections were with the lateral hypothalamic nucleus via the SCP and the ventromedial nucleus via the MCP were observed. Cerebellum takes part in the higher order brain functions via its extensive connections. The knowledge of hypothalamo-cerebellar and cerebello-hypothalamic connections conveyed within the SCP and MCP can be important for the lesions involving the MCP and SCP. These connections can also change the conceptual architecture of the cerebellar circuitry and deepen current understanding.Publication Metadata only Intradural communication between dorsal rootlets of spinal nerves: their clinical significance(Springer, 2015) Solmaz, Bilgehan; Tatarli, Necati; Ceylan, Davut; N/A; Keleş, Güven Evren; Çavdar, Safiye; Faculty Member; Faculty Member; School of Medicine; School of Medicine; N/A; 1995Background Anatomical and surgical textbooks give almost no attention to the intradural communications between dorsal rootlets of adjacent spinal nerves. These communications can be of significance in various neurosurgical procedures and clinical conditions of the region. Methods The spinal cord of six formaldehyde-fixed cadavers was dissected from C1–S5. The dorsal rootlets of the spinal nerves were exposed via a posterior approach and communications between adjacent spinal nerves were documented. Results The frequency of communication between adjacent dorsal rootlets of the spinal nerves showed variations among spinal levels. Thirty-eight dorsal rootlet communications were observed in six cadavers (12 sides) and 20 (52.6 %) were at cervical levels, 14 (36.8 %) at thoracic levels, and four (10.5 %) at lumbar levels. The majority of communications were observed on the left side (65.8 %). Communications were most frequently observed at cervical (C4–C5, C5–C6) and upper thoracic (T1–T2) levels and seen least frequently at lower thoracic and lumbar levels. No communications were observed at sacral levels. Five types of communication were observed: I. oblique ascending, II. oblique descending III. short Y, IV. long Y and V shaped. None of the communication extended beyond one segment at any spinal level. The occurrence of such dorsal rootlet communications ranged from 3 to 7 for each cadaver and the mean was 4.8±1.3. Histological sections from various levels of the dorsal rootlet communications showed that all consisted of myelinated fibers of varying diameters. Conclusions Such communications may lead to misinterpretation of the pathology on the basis of clinical signs and symptoms and also should be considered in rhizotomy.Publication Metadata only The contributions to the human dorsal column tracts from the spinal cord laminae(IMR Press, 2016) KirazlI, Özlem; Solmaz, Bilgehan; Çavdar, Safiye; Faculty Member; School of Medicine; 1995The dorsal column tracts (fasciculus gracilis and fasciculus cuneatus) are concerned with discriminative qualities of sensation. There are controversial descriptions related to the relations of dorsal column tracts with the dorsal horn laminae in text-books. The present study aims to define the laminae of the dorsal horn of the spinal cord that contribute fibers to the dorsal column tracts in the cervical, thoracic and lumbar spinal level. Series paraffin spinal cords sections of six formalin-embalmed adult human cadavers were evaluated. The present study shows that dorsal column tracts receive fiber contributions from laminae III and V and from Clarke's dorsal nucleus at varying spinal levels. At upper cervical levels (C1-C4) fiber contributions were from lamina V and few from lamina III, and at lower cervical levels (C5-C8) there were, in addition to these laminae, also contributions from the Clarke's dorsal nucleus. At upper thoracic levels (T1-T4) fiber contributions were from lamina V and few from Clarke's dorsal nucleus. At lower thoracic (T5-T12) and lumbar levels (L1-L5), in contrast, fiber contributions were only from Clarke's dorsal nucleus. The detailed knowledge of organization of the dorsal column tracts of the spinal cord may pave the way for future treatments of the spinal cord injuries.Publication Metadata only Does astrocyte gap junction protein expression differ during development in absence epileptic rats?(Wiley, 2022) Özkan, Mazhar; N/A; Sur, İlknur Erdem; Çavdar, Safiye; PhD Student; Faculty Member; Faculty Member; Graduate School of Health Sciences; School of Medicine; School of Medicine; N/A; N/A; 1995Intercellular communication via gap junctions (GJs) has a wide variety of complex and essential functions in the CNS. In the present developmental study, we aimed to quantify the number of astrocytic GJs protein connexin 30 (Cx30) of genetic model of absence epilepsy rats from Strasbourg (GAERS) at postnatal P10, P30, and P60 days in the epileptic focal areas involved in the cortico-thalamic circuit. We compared the results with Wistar rats using immunohistochemistry and western blotting. The number of Cx30 immunopositive astrocytes per unit area were quantified for the somatosensory cortex (SSCx), ventrobasal (VB), and lateral geniculate (LGN) thalamic nuclei of the two strains and Cx30 western blot was applied to the tissue samples from the same regions. Both immunohistochemical and western blot results revealed the presence of Cx30 in all regions studied at P10 in both Wistar and GAERS animals. The SSCx, VB, and LGN of Wistar animals showed progressive increase in the number of Cx30 immunopositive labeled astrocytes from P10 to P30 and reached a peak at P30; then a significant decline was observed from P30 to P60 for the SSCx and VB. However, in GAERS Cx30 immunopositive labeled astrocytes showed a progressive increase from P10 to P60 for all brain regions studied. The immunohistochemical data highly corresponded with western blotting results. We conclude that the developmental disproportional expression of Cx30 in the epileptic focal areas in GAERS may be related to the onset of absence seizures or may be related to the neurogenesis of absence epilepsy.Publication Metadata only The supraorbital keyhole approach(Lippincott Williams and Wilkins (LWW), 2015) Tatarli, Necati; Ceylan, Davut; Seker, Askin; Solmaz, Bilgehan; Kilic, Turker; Çavdar, Safiye; Faculty Member; School of Medicine; 1995Aim: The major aim of the present anatomical study was to demonstrate the anatomical structures that can be visualized using the supraorbital keyhole approach, both endoscopically and microscopically, from an eyebrow incision to intracranial structures. Furthermore, it defines an optimal craniotomy for surgery. Methods: Fine dissection was performed on each side of 5 formalin-fixed adult cadavers according to the surgical procedures of the supraorbital keyhole approach, and each step was documented both endoscopically and microscopically. Furthermore, the distance between the superior temporal line and the supraorbital notch/foramen was measured from the 10 total sides of the 5 cadavers and from the 118 sides of the 59 autopsies. Results: Tumors and aneurysms of the anterior cranial fossa can be visualized during the supraorbital keyhole approach. The average distance between the superior temporal line and the supraorbital notch/foramen was measured. The distance obtained from the autopsies on the 25 females was 31.56 +/- 4.03 mm on the right side and 31.04 +/- 5.40 mm on the left side. The average distance obtained from the autopsies on the 34 males was 34.00 +/- 4.59 mm on the right side and 33.59 +/- 5.41 mm on the left side. There was no statistically significant difference between right and left in the female and male autopsies or between sexes. Conclusions: This anatomical study showed that structures in the anterior and middle cranial fossa can be reached via the supraorbital keyhole craniotomy approach with minimal brain retraction and adequate exposure and with minimal craniotomy size.Publication Metadata only Comparison of cerebral ventricular volumes and cortical thicknesses in normal rats and Genetic Absence Epilepsy (GAERS): A developmental study(Pergamon-Elsevier Science Ltd, 2018) Kirazlı, Özlem; Bay, Hüsniye Hacıoğlu; Çakmak, Yusuf Özgür; Onat, Filiz; Çavdar, Safiye; Faculty Member; School of Medicine; 1995Ventricular enlargement and cortical atrophy have been associated with various central nervous system diseases. The aim of the present study was to measure the volumes of the lateral (LV) and third (3V) ventricles and to determine the cortical thickness for the motor (MCx), somatosensory (SSCx), visual (VCx) and auditory (AuCx) cortex and the striatum of Wistar rats, in a developmental series at 10, 20, 30, and 60 days postnatal, and to compare them with similar data from genetic absence epilepsy rats from Strasbourg (GAERS). Serial sections were taken from the brains of Wistar and GAERS animals and were Nissl stained. Photographs were taken from specific sections of the brain for measurements of ventricular volume, cortical and striatal thickness. The image-j computer program was used for the volume and thickness measurements. The data was statistically analyzed by 3-way ANOVA using SPSS 15. Comparison of the measurements of GAERS and Wistar animals showed no statistically significant differences at any of the developmental stages regarding the ventricular (LV and 3V) volumes. However, at P60 and P30 of the MCx, P30 of the SSCx, P20 of the VCx and AuCx showed a significantly thinner cortical thickness in the GAERS than in the Wistar animals. The striatal measurements showed significant decrease in thickness of the striatum at P30 and P60. Further, brain size measurements (between the two temporal poles) showed significant decrease in the size at P30 and P60 of GAERS animals. The presence of thinner cortical and striatal thicknesses and smaller brain size in GAERS animals may suggests that these changes could be involved in the mechanism of epileptogenicity or be a result of the epileptogenicity.Publication Metadata only A variation of the cords of the brachial plexus on the right and a communication between the musculocutaneous and median nerves on the left upper limb: a unique case(Thieme Medical Publishers, 2013) Tatarli, Necati; Ceylan, Davut; Hacioglu, Husniye; Uygun, Seda; Seker, Askin; Çavdar, Safiye; Keleş, Güven Evren; Faculty Member; Faculty Member; School of Medicine; School of Medicine; 1995; N/ADuring routine anatomical dissection of the upper extremity of a 64-year-old cadaver for educational purposes, we observed variations in the brachial plexus on each side. On the right an anomaly of cord formation was present and on the left there was a communication between the musculocutaneous nerve (MCN) and median nerve (MN). On the right side the brachial plexus showed two trunks, superior (C5 and C6) and inferior (C7, C8, and T1); the middle trunk was absent. The superior trunk bifurcated into anterior and posterior divisions, the anterior division continued as the lateral cord forming the MCN. The posterior division gave off the subscapular branch. The inferior trunk trifurcated into radial, median, and ulnar nerves. The radial nerve gave off the axillary and thoracodorsal nerves. The ulnar nerve gave off the median cutaneous nerves of the arm and forearm. The median nerve received a small ascending branch from the MCN. On the right side, there was a communicating branch from the MCN to the MN in the lower third of the arm region. This communicating branch also gave rise to a muscular branch to the brachialis muscle and the lateral cutaneous nerve of forearm. No additional heads of the biceps brachii muscle were observed in either upper limb. Knowledge of the variations of the brachial plexus in humans can be valuable for operations of the shoulder joint and its repair for providing an effective block or treatment for anesthetists and also for explaining otherwise incomprehensible clinical signs for neurologists.Publication Metadata only Comparison of numbers of interneurons in three thalamic nuclei of normal and epileptic rats(Springer, 2014) Bay, Husniye Hacioglu; Yıldız, Sercan D.; Akakin, Dilek; Sirvanci, Serap; Onat, Filiz; Çavdar, Safiye; Faculty Member; School of Medicine; 1995The inhibitory sources in the thalamic nuclei are local interneurons and neurons of the thalamic reticular nucleus. Studies of models of absence epilepsy have shown that the seizures are associated with an excess of inhibitory neurotransmission in the thalamus. In the present study, we used light-microscopic gamma-aminobutyric acid (GABA) immunocytochemistry to quantify the interneurons in the lateral geniculate (LGN), ventral posteromedial (VPM), and ventral posterolateral (VPL) thalamic nuclei, and compared the values from normal Wistar rats and genetic absence epilepsy rats from Strasbourg (GAERS). We found that in both Wistar rats and GAERS, the proportion of interneurons was significantly higher in the LGN than in the VPM and VPL. In the LGN of Wistar rats, 16.4% of the neurons were interneurons and in the GAERS, the value was 15.1%. In the VPM, the proportion of interneurons was 4.2% in Wistar and 14.9% in GAERS; in the VPL the values were 3.7% for Wistar and 11.1% for the GAERS. There was no significant difference between Wistar rats and the GAERS regarding the counts of interneurons in the LGN, whereas the VPM and VPL showed significantly higher counts in GAERS. Comparison of the mean areas of both relay cells and interneuronal profiles showed no significant differences between Wistar rats and GAERS. These findings show that in the VPL and the VPM there are relatively more GABAergic interneurons in GAERS than in Wistar rats. This may represent a compensatory response of the thalamocortical circuitry to the absence seizures or may be related to the production of absence seizures.