Serkan Simsek - Academia.edu (original) (raw)

Papers by Serkan Simsek

Neurosurgery, 2009

OBJECTIVE To evaluate the possible complications of overpenetrated C1 lateral mass screws and to ... more OBJECTIVE To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify and define a “safe zone” area anterior to the C1 vertebra. METHODS The study was performed on 10 cadavers and 50 random patients who had undergone computed tomographic scanning with contrast medium of the neck for other purposes. Atlas lateral mass screw trajectories were plotted, and the safe zone for screw placement anterior to the atlas vertebra was determined for each trajectory. RESULTS The trajectory of the internal carotid artery was measured from its medial wall. The trajectory of the internal carotid artery according to the ideal entrance point of the screw was 11.55 ± 4.55 degrees (range, 2–22 degrees) in the cadavers and 9.78 ± 4.55 degrees (range, −5 to 22 degrees) bilaterally in the patients. At 15 degrees (ideal screw trajectory), the thickness of the rectus capitis anterior muscle and longus capitis muscle was 6.69 ± 0.83 mm (range, 5.32–7.92 mm) in the cadavers and 7.29 ± 1.90 mm (range, 0.50–13.63 mm) bilaterally in the patients. The smallest distance from the internal carotid artery to the anterior cortex of the C1 vertebra was calculated as 4.33 ± 2.03 mm (range, 1.15–8.40 mm) bilaterally in the cadavers and 5.07 ± 1.72 mm (range, 2.15–8.91 mm) bilaterally in radiological specimens. CONCLUSION The internal carotid artery trajectory is lateral to the ideal entrance point of C1 lateral mass screws. The medial angulation of a screw placed in the lateral mass of C1 seemed to increase the margin of safety for the internal carotid artery. The rectus capitis anterior and longus capitis muscles may be thought of as a safe zone area for C1 lateral mass screws. At more than 25 degrees of medial angulation, the risk of perforation of the oropharyngeal wall increases.

Surgical Neurology, 2006

Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subar... more Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subarachnoid hemorrhage is more frequently reported in these patients. Spontaneous resolution of cSDH in patients with idiopathic subdural hematoma is uncommon. Case Description: We report a case of spontaneous cSDH in a patient with ITP, and we review the related cases in the literature. In our patient, the hematoma resolved spontaneously despite very low platelet levels. There also was an incidental left parietal convexity meningioma. A review of the literature is presented, and the management of the patients is discussed. Conclusion: In patients with ITP, cSDHs may resolve spontaneously or with medical treatment, and surgery might be deferred except in emergency conditions or in patients with normal neurological findings. Close neurological and radiological observation along with the medical treatment may be appropriate in the management of patients with normal neurological findings. D

Turkish neurosurgery, 2009

To date, few studies have addressed the subaxial vertebrectomy technique and related anatomical l... more To date, few studies have addressed the subaxial vertebrectomy technique and related anatomical landmarks in this method. Total spondylectomy is performed via piecemeal resection or en bloc removal in a one-stage procedure associated with stabilizing the spine and preserving neurological status. In this presentation, a circumferential total cervical tumor resection for subaxial cervical spine lesions was described. Two cases of subaxial cervical malignancy, one with primary C3 chondrosarcoma and the other with C4 lung adenosarcoma metastasis, were both treated by the anterior-posterior approach. The lesions could be removed macroscopically totally in both cases. The patients did well after surgery with preserved neurological status and they survived a considerable period without tumor recurrence. Subaxial total tumor resection can be performed safely while preserving vertebral arteries with adequate anatomical knowledge and careful surgical planning, and circumferential vertebrectom...

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2009

Although various posterior insertion angles for screw insertion have been proposed for C1 lateral... more Although various posterior insertion angles for screw insertion have been proposed for C1 lateral mass, substantial conclusions have not been reached regarding ideal angles and average length of the screw yet. We aimed to re-consider the morphometry and the ideal trajections of the C1 screw. Morphometric analysis was performed on 40 Turkish dried atlas vertebrae obtained from the Department of Anatomy at the Medical School of Ankara University. The quantitative anatomy of the screw entry zone, trajectories, and the ideal lengths of the screws were calculated to evaluate the feasibility of posterior screw fixation of the lateral mass of the atlas. The entry point into the lateral mass of the atlas is the intersection of the posterior arch and the C1 lateral mass. The optimum medial angle is 13.5 +/- 1.9 degrees and maximal angle of medialization is 29.4 +/- 3.0 degrees . The ideal cephalic angle is 15.2 +/- 2.6 degrees , and the maximum cephalic angle is 29.6 +/- 2.6 degrees . The op...

Although C1 lateral mass fixation technique is frequently performed in upper cervical instabiliti... more Although C1 lateral mass fixation technique is frequently performed in upper cervical instabilities, it requires the guidance of fluoroscopic imaging. The fluoroscopy guidance is time-consuming and has the risks of accumulative radiation. Biplane fluoroscopy is also difficult in upper cervical pathologic conditions because of the use of cranial fixations. This study aimed to demonstrate that unicortical C1 lateral mass screws could be placed safely and rapidly without fluoroscopy guidance. Between 2002 and 2008, 32 C1 lateral mass screws were inserted in 17 consecutive patients with various pathologic conditions involving either atlantoaxial or occipitocervical instability. C1 screw lengths ranged from 18 to 32 mm. The atlantoaxial fixation was performed in 13 patients, and C1 lateral mass screws were added to the occipitocervical construct in 3 patients, to the posterior cervical construct in 2 patients, and to the cervicothoracic construct in 1 patient. In 2 patients, because C1 lateral mass screws could not be inserted unilaterally, C1 pedicle screw analogs were inserted. There were no screw malpositions or neurovascular complications related to screw insertion. Operation time and intraoperative bleeding of the isolated atlantoaxial fixations were retrospectively evaluated. The mean follow-up was 32.3 months (range, 7-59 months). No screw loosening or construct failure was observed within this period. Postoperatively, 4 patients complained of hypoesthesia, whereas one patient had superficial wound infection. C1 lateral mass screws may be used safely and rapidly in upper cervical instabilities without intraoperative fluoroscopy guidance and the use of the spinal navigation systems. Preoperative planning and determining the ideal screw insertion point, the ideal trajections, and the lengths of the screws are the most important points.

Journal of neurosurgery. Spine, 2013

The object of this investigation was to conduct a morphometric study in cadavers to determine ana... more The object of this investigation was to conduct a morphometric study in cadavers to determine anatomical structures, their relationships, and their morphometry for subaxial cervical spondylectomy. Forty sides of 20 cadavers were used for this study. Dissections were performed in 2 stages (anteriorly and posteriorly). Twenty-one morphometric measurements were performed for both sides of the C3-6 vertebrae. Data were analyzed statistically. Morphometry of the laminas, tuberculum posterius, pedicle, corpus, foramen transversarium, and processus costalis were measured. Detailed quantitative anatomical knowledge for operations requiring wide dissection and resection, such as cervical spondylectomy, lowers the morbidity rate.

Turkish neurosurgery, 2013

Aneurysmal bone cyst is a benign tumor-like bony lesion with a propensity to develop in the pedia... more Aneurysmal bone cyst is a benign tumor-like bony lesion with a propensity to develop in the pediatric population. It generally involves one vertebral level when localized to the spine. The degree of resection correlates highly with fewer recurrences. En bloc spondylectomy is the procedure of choice for this reason, but its high complication rate has led to the development of alternative surgical methods. This paper presents a three-level aneurysmal bone cyst that was excised totally in two stages, and the safety and efficacy of this method especially in the pediatric population are emphasized. This paper also states that anterior and posterior instrumented fusions are necessary in spite of the growing spine.

Turkish Neurosurgery, 2010

The cubital tunnel syndrome is widely considered as the second most frequent compression neuropat... more The cubital tunnel syndrome is widely considered as the second most frequent compression neuropathy in the upper extremities although the existence of a compressive cause has not been determined conclusively. As far as we know, operational photography of compression of the ulnar nerve at the elbow is almost never found in the literature. In this paper, operational and pathological photographs of the Osborne's ligament as a cause of ulnar entrapment neuropathy at the elbow are presented. There is still an ambiguity as to whether compressive or tractional etiology or both of these factors may occur progressively to be a factor in the development of neuropathy. This report may be considered as concrete evidence for the compressive etiology for ulnar neuropathies.

Neurosurgery, 2009

To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify a... more To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify and define a "safe zone" area anterior to the C1 vertebra. The study was performed on 10 cadavers and 50 random patients who had undergone computed tomographic scanning with contrast medium of the neck for other purposes. Atlas lateral mass screw trajectories were plotted, and the safe zone for screw placement anterior to the atlas vertebra was determined for each trajectory. The trajectory of the internal carotid artery was measured from its medial wall. The trajectory of the internal carotid artery according to the ideal entrance point of the screw was 11.55 +/- 4.55 degrees (range, 2-22 degrees) in the cadavers and 9.78 +/- 4.55 degrees (range, -5 to 22 degrees) bilaterally in the patients. At 15 degrees (ideal screw trajectory), the thickness of the rectus capitis anterior muscle and longus capitis muscle was 6.69 +/- 0.83 mm (range, 5.32-7.92 mm) in the cadavers and 7.29 +/- 1.90 mm (range, 0.50-13.63 mm) bilaterally in the patients. The smallest distance from the internal carotid artery to the anterior cortex of the C1 vertebra was calculated as 4.33 +/- 2.03 mm (range, 1.15-8.40 mm) bilaterally in the cadavers and 5.07 +/- 1.72 mm (range, 2.15-8.91 mm) bilaterally in radiological specimens. The internal carotid artery trajectory is lateral to the ideal entrance point of C1 lateral mass screws. The medial angulation of a screw placed in the lateral mass of C1 seemed to increase the margin of safety for the internal carotid artery. The rectus capitis anterior and longus capitis muscles may be thought of as a safe zone area for C1 lateral mass screws. At more than 25 degrees of medial angulation, the risk of perforation of the oropharyngeal wall increases.

Surgical Neurology, 2006

Background: In the management of basilar invagination, traction therapy may help by pulling down ... more Background: In the management of basilar invagination, traction therapy may help by pulling down the odontoid process away from the brain stem that may result in clinical and radiological improvement. We aimed to discuss the role of the halo vest apparatus traction on the reduction of severe anterior compression pathologies in basilar invagination. Case Description: We describe a simple and safe cervical traction method by the halo vest apparatus that is followed by rigid posterior occipitocervical fixation and foramen magnum decompression in a patient who presented with basilar invagination and symptoms of severe brain stem compression. An MR-suitable halo vest apparatus was used for reduction of the deformity. The reduction of the basilar invagination was achieved gradually by distracting the halo crown in stages. Conclusion: The halo vest apparatus can be safely used in complex craniocervical junction anomalies. An effective cervical traction can be performed in basilar invagination, and reduction of the deformity may be achieved without the risk of overdistraction. In some cases, even partial reduction of the deformity may facilitate brain stem and spinal cord relief without any need of posterior decompression. Patients may benefit from ambulatory functions because bed rest is eliminated in this procedure. Neurovascular structures and the degree of the reduction can be observed on MRIs when an MR-suitable device is used.

Surgical Neurology, 2006

Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subar... more Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subarachnoid hemorrhage is more frequently reported in these patients. Spontaneous resolution of cSDH in patients with idiopathic subdural hematoma is uncommon. Case Description: We report a case of spontaneous cSDH in a patient with ITP, and we review the related cases in the literature. In our patient, the hematoma resolved spontaneously despite very low platelet levels. There also was an incidental left parietal convexity meningioma. A review of the literature is presented, and the management of the patients is discussed. Conclusion: In patients with ITP, cSDHs may resolve spontaneously or with medical treatment, and surgery might be deferred except in emergency conditions or in patients with normal neurological findings. Close neurological and radiological observation along with the medical treatment may be appropriate in the management of patients with normal neurological findings. D

Surgical Neurology, 2009

Background: The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasos... more Background: The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasospasm in a rabbit model of SAH. Methods: Thirty-four New Zealand white rabbits were allocated into 3 groups randomly. Subarachnoid hemorrhage was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH [n = 12]), (2) SAH only (n = 12), and (3) SAH plus RLX (n = 10). Basilar artery lumen areas and arterial wall thickness were measured to assess vasospams in all groups. Results: There was a statistically significant difference between the mean basilar artery crosssectional areas and the mean arterial wall thickness measurements of the control and SAH-only groups (P b .05). The difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements in the RLX-treated group was statistically significant (P b .05). The difference between the SAH group and the SAH + RLX group was also statistically significant (P b .05). Conclusions: These findings demonstrate that RLX has marked vasodilatatory effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this SERM drug could be used as possible anti-vasospastic agent in patients without major adverse effects.

Surgical Neurology, 2008

Background: Increasing evidence implicates voltage-dependent sodium and potassium channels, in ad... more Background: Increasing evidence implicates voltage-dependent sodium and potassium channels, in addition to calcium channels of various types, in the pathophysiological development of cerebral vasospasm. This study investigated the ability of LTG, an antiepileptic drug with multi-ion channel inhibition properties, to prevent cerebral vasospasm and subsequent neural ischemia in a rabbit model of SAH. Methods: Thirty-five New Zealand white rabbits were assigned to 1 of 3 groups: (1) control (no SAH, saline injection); (2) SAH alone; (3) SAH + LTG, 20 mg/kg daily. Animals were killed 72 hours after SAH, then basilar artery lumen areas and arterial wall thickness were measured in all groups. The histological sections of the CA1 and CA3 regions and dentate gyri of the hippocampi were evaluated semiquantitatively for neural tissue degeneration. Results: In the SAH group, the mean luminal cross-sectional area of the basilar artery was reduced by 62% after SAH as compared with the non-SAH controls (P b .0001). After SAH, the vasospastic response was attenuated by 36% in animals treated with 20 mg/kg of LTG compared with the SAH group (P b .005). The mean luminal cross-sectional areas of the basilar artery were 279 000 ± 27 000 μm 2 in the control group, 173 000 ± 17 600 μm 2 in the SAH group, and 236 000 ± 10 000 μm 2 in the SAH + LTG group. The differences between the SAH group and the LTG-treated group were statistically significant (P b .0001). Histological examination was done in 12 control, 12 SAH, and 9 SAH + LTG-treated animals. The mean degeneration score for the control group and SAH + LTG group was statistically significant (P = .012). The difference between the SAH group and SAH+ LTG group was also statistically significant (P = .006). Conclusions: These findings demonstrate that oral administration of LTG has marked neuroprotective effect and significantly attenuates cerebral vasospasm after SAH, thus providing additional support for the role of non-L-type calcium channels and voltage-dependent sodium channels in vasospasm.

Surgical Neurology, 2007

Background: Atlantoaxial subluxation secondary to a paravertebral (retropharyngeal) abscess is a ... more Background: Atlantoaxial subluxation secondary to a paravertebral (retropharyngeal) abscess is a well known but rare event in children. Case Description: The authors describe the clinical and radiologic findings of a case of 6-year-old child who presented with acute torticollis (duration, 4 days). Type 2 atlantoaxial rotatory fixation and upper cervical paravertebral (retropharyngeal) abscess were diagnosed on radiologic examination. Laboratory test results showed positive agglutination titer for Brucella melitensis, in the rate of 1/640 dilution. This is the first reported case of Brucella-related atlantoaxial subluxation in a child in the pediatric literature. The patient was treated successfully with anti-inflammatory drugs, Brucellaspecific antibiotic regimen, and Philadelphia collar application. Possibly, effusion of the atlantoaxial joint, due to Brucella infection, led to the laxity of the ligaments and contributed to subluxation. Conclusions: Brucella abscess should be kept in mind for the differential diagnosis of retropharyngeal mass, and the torticollis may be the only presenting sign. The authors recommend a trial of medical treatment with adequate dosages for a reasonable length of time and immobilization before considering surgical intervention for the spinal paravertebral Brucella abscess and related atlantoaxial subluxation. D

Pediatric Neurosurgery, 2006

Atlantoaxial rotatory fixation is an uncommon disorder of childhood, which can be treated conserv... more Atlantoaxial rotatory fixation is an uncommon disorder of childhood, which can be treated conservatively when diagnosed early. Although spontaneous correction occasionally occurs, most of the patients usually benefit from collar or traction therapies. If there is no intervention or if all external therapeutic modalities fail, the deformity may become chronic and irreducible. In such rare cases, surgical correction and stabilization are needed to prevent future head and neck deformity or facial asymmetry. In this report we describe a novel surgical technique used in a pediatric case presenting with delayed type 2 atlantoaxial rotatory fixation, in whom all external reduction methods had failed. The patient's deformity was treated by occiput-C2 pedicle polyaxial screw stabilization. This technique is effective for reducing the atlantoaxial fixation in children.

Neurosurgery, 2006

WE STUDY HISTORY in an attempt to achieve a wide perspective of life and reality. Spinal disorder... more WE STUDY HISTORY in an attempt to achieve a wide perspective of life and reality. Spinal disorders, particularly spine traumas and their complications, have been one of the most challenging problems throughout the history of medicine and, indeed, throughout the history of humanity. The pioneers and founders of scientific medicine committed much of their lives to understanding these disorders. There is a paucity of historical documentation. From the extraordinary efforts of early practitioners, we may glean insight relevant to the more effective treatment of such debilitating disorders. Ibn Sina (Avicenna), who lived in the medieval period, was one such physician. His principal book of medicine, The Canon, played a fundamental role in the practice of medicine in the Eastern and Western worlds between the 11th and 17th centuries. In this book, published in the 11th century, he provided detailed accounts of spinal disorders and strategies for their management. Here, we provide a brief review of Avicenna's most significant points concerning spinal diseases and their treatment from the chapters of the Canon. Although, there are not basic differences from Hippocratic knowledge, this book contains some original contributions.

Neurological Research, 2009

The aim of this study was to investigate the ability of topiramate (TPM) to prevent neural injury... more The aim of this study was to investigate the ability of topiramate (TPM) to prevent neural injury in a rabbit model of subarachnoid hemorrhage (SAH). The effect of TPM on cerebral vasospasm was also evaluated. Fifty-three New Zealand white rabbits were allocated into three groups randomly. SAH was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH (n=18); (2) SAH only (n=17); (3) SAH + TPM (n=18). Hippocampal sections were evaluated for neural tissue degeneration, using the previously described neural degeneration scoring system. The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corp., former Intergen) was used to assess apoptosis in the hippocampal sections and the effect of TPM on the apoptotic response. Basilar artery lumen areas and arterial wall thickness were also measured in all groups. There was a statistically significant difference between the mean degeneration scores of the control and SAH only groups (p<0.05). The level of neural degeneration in TPM treated group was significantly lower compared with SAH only group (p<0.05), but not significantly higher than the control group (p>0.05). There were no statistically significant differences between arterial cross-sectional area and arterial wall thickness measurements of the SAH group and SAH + TPM group. These findings demonstrate that TPM has marked neuroprotective effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this antiepileptic drug could be used as a possible neuroprotective agent in patients without major adverse effects.

Journal of Neurosurgery, 2000

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2008

The sulcus of the vertebral artery is located behind the lateral mass of the atlas and in some ca... more The sulcus of the vertebral artery is located behind the lateral mass of the atlas and in some cases is converted into a foramen by anomalous ossification known as the posterior ponticulus (osseous bridge). This study involved anatomical observations of 158 isolated anatomical specimens of dry C1 vertebrae. The incidence and types of posterior osseous bridging were identified for the 158 dry samples of atlas vertebrae. In nine (5.6%) dry C1 vertebrae, partial osseous bridging was detected (bilaterally in eight vertebrae and unilaterally on the left in one). Complete osseous bridging (arcuate foramen) was observed in six (3.8%) dry C1 vertebrae (bilaterally in one vertebra, unilaterally on the left in three, and on the right in two). Awareness of the types of posterior osseous bridging of C1 in craniocervical junction surgery is essential, and may be helpful in surgical interventions in this region.

Acta Neurochirurgica, 2007

Background. Though cerebral vasospasm is one of the most serious complications of subarachnoid ha... more Background. Though cerebral vasospasm is one of the most serious complications of subarachnoid haemorrhage (SAH), its complex pathogenesis is poorly understood and available clinical treatment options are unsatisfactory. This study was designed to examine the efficacy of leflunomide, an immunomodulatory agent with inhibitory properties, on vascular smooth muscle cell proliferation and inflammation in a rabbit cerebral vasospasm model.

Neurosurgery, 2009

OBJECTIVE To evaluate the possible complications of overpenetrated C1 lateral mass screws and to ... more OBJECTIVE To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify and define a “safe zone” area anterior to the C1 vertebra. METHODS The study was performed on 10 cadavers and 50 random patients who had undergone computed tomographic scanning with contrast medium of the neck for other purposes. Atlas lateral mass screw trajectories were plotted, and the safe zone for screw placement anterior to the atlas vertebra was determined for each trajectory. RESULTS The trajectory of the internal carotid artery was measured from its medial wall. The trajectory of the internal carotid artery according to the ideal entrance point of the screw was 11.55 ± 4.55 degrees (range, 2–22 degrees) in the cadavers and 9.78 ± 4.55 degrees (range, −5 to 22 degrees) bilaterally in the patients. At 15 degrees (ideal screw trajectory), the thickness of the rectus capitis anterior muscle and longus capitis muscle was 6.69 ± 0.83 mm (range, 5.32–7.92 mm) in the cadavers and 7.29 ± 1.90 mm (range, 0.50–13.63 mm) bilaterally in the patients. The smallest distance from the internal carotid artery to the anterior cortex of the C1 vertebra was calculated as 4.33 ± 2.03 mm (range, 1.15–8.40 mm) bilaterally in the cadavers and 5.07 ± 1.72 mm (range, 2.15–8.91 mm) bilaterally in radiological specimens. CONCLUSION The internal carotid artery trajectory is lateral to the ideal entrance point of C1 lateral mass screws. The medial angulation of a screw placed in the lateral mass of C1 seemed to increase the margin of safety for the internal carotid artery. The rectus capitis anterior and longus capitis muscles may be thought of as a safe zone area for C1 lateral mass screws. At more than 25 degrees of medial angulation, the risk of perforation of the oropharyngeal wall increases.

Surgical Neurology, 2006

Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subar... more Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subarachnoid hemorrhage is more frequently reported in these patients. Spontaneous resolution of cSDH in patients with idiopathic subdural hematoma is uncommon. Case Description: We report a case of spontaneous cSDH in a patient with ITP, and we review the related cases in the literature. In our patient, the hematoma resolved spontaneously despite very low platelet levels. There also was an incidental left parietal convexity meningioma. A review of the literature is presented, and the management of the patients is discussed. Conclusion: In patients with ITP, cSDHs may resolve spontaneously or with medical treatment, and surgery might be deferred except in emergency conditions or in patients with normal neurological findings. Close neurological and radiological observation along with the medical treatment may be appropriate in the management of patients with normal neurological findings. D

Turkish neurosurgery, 2009

To date, few studies have addressed the subaxial vertebrectomy technique and related anatomical l... more To date, few studies have addressed the subaxial vertebrectomy technique and related anatomical landmarks in this method. Total spondylectomy is performed via piecemeal resection or en bloc removal in a one-stage procedure associated with stabilizing the spine and preserving neurological status. In this presentation, a circumferential total cervical tumor resection for subaxial cervical spine lesions was described. Two cases of subaxial cervical malignancy, one with primary C3 chondrosarcoma and the other with C4 lung adenosarcoma metastasis, were both treated by the anterior-posterior approach. The lesions could be removed macroscopically totally in both cases. The patients did well after surgery with preserved neurological status and they survived a considerable period without tumor recurrence. Subaxial total tumor resection can be performed safely while preserving vertebral arteries with adequate anatomical knowledge and careful surgical planning, and circumferential vertebrectom...

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2009

Although various posterior insertion angles for screw insertion have been proposed for C1 lateral... more Although various posterior insertion angles for screw insertion have been proposed for C1 lateral mass, substantial conclusions have not been reached regarding ideal angles and average length of the screw yet. We aimed to re-consider the morphometry and the ideal trajections of the C1 screw. Morphometric analysis was performed on 40 Turkish dried atlas vertebrae obtained from the Department of Anatomy at the Medical School of Ankara University. The quantitative anatomy of the screw entry zone, trajectories, and the ideal lengths of the screws were calculated to evaluate the feasibility of posterior screw fixation of the lateral mass of the atlas. The entry point into the lateral mass of the atlas is the intersection of the posterior arch and the C1 lateral mass. The optimum medial angle is 13.5 +/- 1.9 degrees and maximal angle of medialization is 29.4 +/- 3.0 degrees . The ideal cephalic angle is 15.2 +/- 2.6 degrees , and the maximum cephalic angle is 29.6 +/- 2.6 degrees . The op...

Although C1 lateral mass fixation technique is frequently performed in upper cervical instabiliti... more Although C1 lateral mass fixation technique is frequently performed in upper cervical instabilities, it requires the guidance of fluoroscopic imaging. The fluoroscopy guidance is time-consuming and has the risks of accumulative radiation. Biplane fluoroscopy is also difficult in upper cervical pathologic conditions because of the use of cranial fixations. This study aimed to demonstrate that unicortical C1 lateral mass screws could be placed safely and rapidly without fluoroscopy guidance. Between 2002 and 2008, 32 C1 lateral mass screws were inserted in 17 consecutive patients with various pathologic conditions involving either atlantoaxial or occipitocervical instability. C1 screw lengths ranged from 18 to 32 mm. The atlantoaxial fixation was performed in 13 patients, and C1 lateral mass screws were added to the occipitocervical construct in 3 patients, to the posterior cervical construct in 2 patients, and to the cervicothoracic construct in 1 patient. In 2 patients, because C1 lateral mass screws could not be inserted unilaterally, C1 pedicle screw analogs were inserted. There were no screw malpositions or neurovascular complications related to screw insertion. Operation time and intraoperative bleeding of the isolated atlantoaxial fixations were retrospectively evaluated. The mean follow-up was 32.3 months (range, 7-59 months). No screw loosening or construct failure was observed within this period. Postoperatively, 4 patients complained of hypoesthesia, whereas one patient had superficial wound infection. C1 lateral mass screws may be used safely and rapidly in upper cervical instabilities without intraoperative fluoroscopy guidance and the use of the spinal navigation systems. Preoperative planning and determining the ideal screw insertion point, the ideal trajections, and the lengths of the screws are the most important points.

Journal of neurosurgery. Spine, 2013

The object of this investigation was to conduct a morphometric study in cadavers to determine ana... more The object of this investigation was to conduct a morphometric study in cadavers to determine anatomical structures, their relationships, and their morphometry for subaxial cervical spondylectomy. Forty sides of 20 cadavers were used for this study. Dissections were performed in 2 stages (anteriorly and posteriorly). Twenty-one morphometric measurements were performed for both sides of the C3-6 vertebrae. Data were analyzed statistically. Morphometry of the laminas, tuberculum posterius, pedicle, corpus, foramen transversarium, and processus costalis were measured. Detailed quantitative anatomical knowledge for operations requiring wide dissection and resection, such as cervical spondylectomy, lowers the morbidity rate.

Turkish neurosurgery, 2013

Aneurysmal bone cyst is a benign tumor-like bony lesion with a propensity to develop in the pedia... more Aneurysmal bone cyst is a benign tumor-like bony lesion with a propensity to develop in the pediatric population. It generally involves one vertebral level when localized to the spine. The degree of resection correlates highly with fewer recurrences. En bloc spondylectomy is the procedure of choice for this reason, but its high complication rate has led to the development of alternative surgical methods. This paper presents a three-level aneurysmal bone cyst that was excised totally in two stages, and the safety and efficacy of this method especially in the pediatric population are emphasized. This paper also states that anterior and posterior instrumented fusions are necessary in spite of the growing spine.

Turkish Neurosurgery, 2010

The cubital tunnel syndrome is widely considered as the second most frequent compression neuropat... more The cubital tunnel syndrome is widely considered as the second most frequent compression neuropathy in the upper extremities although the existence of a compressive cause has not been determined conclusively. As far as we know, operational photography of compression of the ulnar nerve at the elbow is almost never found in the literature. In this paper, operational and pathological photographs of the Osborne's ligament as a cause of ulnar entrapment neuropathy at the elbow are presented. There is still an ambiguity as to whether compressive or tractional etiology or both of these factors may occur progressively to be a factor in the development of neuropathy. This report may be considered as concrete evidence for the compressive etiology for ulnar neuropathies.

Neurosurgery, 2009

To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify a... more To evaluate the possible complications of overpenetrated C1 lateral mass screws and to identify and define a "safe zone" area anterior to the C1 vertebra. The study was performed on 10 cadavers and 50 random patients who had undergone computed tomographic scanning with contrast medium of the neck for other purposes. Atlas lateral mass screw trajectories were plotted, and the safe zone for screw placement anterior to the atlas vertebra was determined for each trajectory. The trajectory of the internal carotid artery was measured from its medial wall. The trajectory of the internal carotid artery according to the ideal entrance point of the screw was 11.55 +/- 4.55 degrees (range, 2-22 degrees) in the cadavers and 9.78 +/- 4.55 degrees (range, -5 to 22 degrees) bilaterally in the patients. At 15 degrees (ideal screw trajectory), the thickness of the rectus capitis anterior muscle and longus capitis muscle was 6.69 +/- 0.83 mm (range, 5.32-7.92 mm) in the cadavers and 7.29 +/- 1.90 mm (range, 0.50-13.63 mm) bilaterally in the patients. The smallest distance from the internal carotid artery to the anterior cortex of the C1 vertebra was calculated as 4.33 +/- 2.03 mm (range, 1.15-8.40 mm) bilaterally in the cadavers and 5.07 +/- 1.72 mm (range, 2.15-8.91 mm) bilaterally in radiological specimens. The internal carotid artery trajectory is lateral to the ideal entrance point of C1 lateral mass screws. The medial angulation of a screw placed in the lateral mass of C1 seemed to increase the margin of safety for the internal carotid artery. The rectus capitis anterior and longus capitis muscles may be thought of as a safe zone area for C1 lateral mass screws. At more than 25 degrees of medial angulation, the risk of perforation of the oropharyngeal wall increases.

Surgical Neurology, 2006

Background: In the management of basilar invagination, traction therapy may help by pulling down ... more Background: In the management of basilar invagination, traction therapy may help by pulling down the odontoid process away from the brain stem that may result in clinical and radiological improvement. We aimed to discuss the role of the halo vest apparatus traction on the reduction of severe anterior compression pathologies in basilar invagination. Case Description: We describe a simple and safe cervical traction method by the halo vest apparatus that is followed by rigid posterior occipitocervical fixation and foramen magnum decompression in a patient who presented with basilar invagination and symptoms of severe brain stem compression. An MR-suitable halo vest apparatus was used for reduction of the deformity. The reduction of the basilar invagination was achieved gradually by distracting the halo crown in stages. Conclusion: The halo vest apparatus can be safely used in complex craniocervical junction anomalies. An effective cervical traction can be performed in basilar invagination, and reduction of the deformity may be achieved without the risk of overdistraction. In some cases, even partial reduction of the deformity may facilitate brain stem and spinal cord relief without any need of posterior decompression. Patients may benefit from ambulatory functions because bed rest is eliminated in this procedure. Neurovascular structures and the degree of the reduction can be observed on MRIs when an MR-suitable device is used.

Surgical Neurology, 2006

Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subar... more Background: cSDH is a rare form of bleeding in patients with ITP. Intracerebral hematoma or subarachnoid hemorrhage is more frequently reported in these patients. Spontaneous resolution of cSDH in patients with idiopathic subdural hematoma is uncommon. Case Description: We report a case of spontaneous cSDH in a patient with ITP, and we review the related cases in the literature. In our patient, the hematoma resolved spontaneously despite very low platelet levels. There also was an incidental left parietal convexity meningioma. A review of the literature is presented, and the management of the patients is discussed. Conclusion: In patients with ITP, cSDHs may resolve spontaneously or with medical treatment, and surgery might be deferred except in emergency conditions or in patients with normal neurological findings. Close neurological and radiological observation along with the medical treatment may be appropriate in the management of patients with normal neurological findings. D

Surgical Neurology, 2009

Background: The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasos... more Background: The aim of this study was to investigate the ability of a SERM, RLX, to prevent vasospasm in a rabbit model of SAH. Methods: Thirty-four New Zealand white rabbits were allocated into 3 groups randomly. Subarachnoid hemorrhage was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH [n = 12]), (2) SAH only (n = 12), and (3) SAH plus RLX (n = 10). Basilar artery lumen areas and arterial wall thickness were measured to assess vasospams in all groups. Results: There was a statistically significant difference between the mean basilar artery crosssectional areas and the mean arterial wall thickness measurements of the control and SAH-only groups (P b .05). The difference between the mean basilar artery cross-sectional areas and the mean arterial wall thickness measurements in the RLX-treated group was statistically significant (P b .05). The difference between the SAH group and the SAH + RLX group was also statistically significant (P b .05). Conclusions: These findings demonstrate that RLX has marked vasodilatatory effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this SERM drug could be used as possible anti-vasospastic agent in patients without major adverse effects.

Surgical Neurology, 2008

Background: Increasing evidence implicates voltage-dependent sodium and potassium channels, in ad... more Background: Increasing evidence implicates voltage-dependent sodium and potassium channels, in addition to calcium channels of various types, in the pathophysiological development of cerebral vasospasm. This study investigated the ability of LTG, an antiepileptic drug with multi-ion channel inhibition properties, to prevent cerebral vasospasm and subsequent neural ischemia in a rabbit model of SAH. Methods: Thirty-five New Zealand white rabbits were assigned to 1 of 3 groups: (1) control (no SAH, saline injection); (2) SAH alone; (3) SAH + LTG, 20 mg/kg daily. Animals were killed 72 hours after SAH, then basilar artery lumen areas and arterial wall thickness were measured in all groups. The histological sections of the CA1 and CA3 regions and dentate gyri of the hippocampi were evaluated semiquantitatively for neural tissue degeneration. Results: In the SAH group, the mean luminal cross-sectional area of the basilar artery was reduced by 62% after SAH as compared with the non-SAH controls (P b .0001). After SAH, the vasospastic response was attenuated by 36% in animals treated with 20 mg/kg of LTG compared with the SAH group (P b .005). The mean luminal cross-sectional areas of the basilar artery were 279 000 ± 27 000 μm 2 in the control group, 173 000 ± 17 600 μm 2 in the SAH group, and 236 000 ± 10 000 μm 2 in the SAH + LTG group. The differences between the SAH group and the LTG-treated group were statistically significant (P b .0001). Histological examination was done in 12 control, 12 SAH, and 9 SAH + LTG-treated animals. The mean degeneration score for the control group and SAH + LTG group was statistically significant (P = .012). The difference between the SAH group and SAH+ LTG group was also statistically significant (P = .006). Conclusions: These findings demonstrate that oral administration of LTG has marked neuroprotective effect and significantly attenuates cerebral vasospasm after SAH, thus providing additional support for the role of non-L-type calcium channels and voltage-dependent sodium channels in vasospasm.

Surgical Neurology, 2007

Background: Atlantoaxial subluxation secondary to a paravertebral (retropharyngeal) abscess is a ... more Background: Atlantoaxial subluxation secondary to a paravertebral (retropharyngeal) abscess is a well known but rare event in children. Case Description: The authors describe the clinical and radiologic findings of a case of 6-year-old child who presented with acute torticollis (duration, 4 days). Type 2 atlantoaxial rotatory fixation and upper cervical paravertebral (retropharyngeal) abscess were diagnosed on radiologic examination. Laboratory test results showed positive agglutination titer for Brucella melitensis, in the rate of 1/640 dilution. This is the first reported case of Brucella-related atlantoaxial subluxation in a child in the pediatric literature. The patient was treated successfully with anti-inflammatory drugs, Brucellaspecific antibiotic regimen, and Philadelphia collar application. Possibly, effusion of the atlantoaxial joint, due to Brucella infection, led to the laxity of the ligaments and contributed to subluxation. Conclusions: Brucella abscess should be kept in mind for the differential diagnosis of retropharyngeal mass, and the torticollis may be the only presenting sign. The authors recommend a trial of medical treatment with adequate dosages for a reasonable length of time and immobilization before considering surgical intervention for the spinal paravertebral Brucella abscess and related atlantoaxial subluxation. D

Pediatric Neurosurgery, 2006

Atlantoaxial rotatory fixation is an uncommon disorder of childhood, which can be treated conserv... more Atlantoaxial rotatory fixation is an uncommon disorder of childhood, which can be treated conservatively when diagnosed early. Although spontaneous correction occasionally occurs, most of the patients usually benefit from collar or traction therapies. If there is no intervention or if all external therapeutic modalities fail, the deformity may become chronic and irreducible. In such rare cases, surgical correction and stabilization are needed to prevent future head and neck deformity or facial asymmetry. In this report we describe a novel surgical technique used in a pediatric case presenting with delayed type 2 atlantoaxial rotatory fixation, in whom all external reduction methods had failed. The patient's deformity was treated by occiput-C2 pedicle polyaxial screw stabilization. This technique is effective for reducing the atlantoaxial fixation in children.

Neurosurgery, 2006

WE STUDY HISTORY in an attempt to achieve a wide perspective of life and reality. Spinal disorder... more WE STUDY HISTORY in an attempt to achieve a wide perspective of life and reality. Spinal disorders, particularly spine traumas and their complications, have been one of the most challenging problems throughout the history of medicine and, indeed, throughout the history of humanity. The pioneers and founders of scientific medicine committed much of their lives to understanding these disorders. There is a paucity of historical documentation. From the extraordinary efforts of early practitioners, we may glean insight relevant to the more effective treatment of such debilitating disorders. Ibn Sina (Avicenna), who lived in the medieval period, was one such physician. His principal book of medicine, The Canon, played a fundamental role in the practice of medicine in the Eastern and Western worlds between the 11th and 17th centuries. In this book, published in the 11th century, he provided detailed accounts of spinal disorders and strategies for their management. Here, we provide a brief review of Avicenna's most significant points concerning spinal diseases and their treatment from the chapters of the Canon. Although, there are not basic differences from Hippocratic knowledge, this book contains some original contributions.

Neurological Research, 2009

The aim of this study was to investigate the ability of topiramate (TPM) to prevent neural injury... more The aim of this study was to investigate the ability of topiramate (TPM) to prevent neural injury in a rabbit model of subarachnoid hemorrhage (SAH). The effect of TPM on cerebral vasospasm was also evaluated. Fifty-three New Zealand white rabbits were allocated into three groups randomly. SAH was induced by injecting autologous blood into the cisterna magna. The treatment groups were as follows: (1) sham operated (no SAH (n=18); (2) SAH only (n=17); (3) SAH + TPM (n=18). Hippocampal sections were evaluated for neural tissue degeneration, using the previously described neural degeneration scoring system. The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corp., former Intergen) was used to assess apoptosis in the hippocampal sections and the effect of TPM on the apoptotic response. Basilar artery lumen areas and arterial wall thickness were also measured in all groups. There was a statistically significant difference between the mean degeneration scores of the control and SAH only groups (p<0.05). The level of neural degeneration in TPM treated group was significantly lower compared with SAH only group (p<0.05), but not significantly higher than the control group (p>0.05). There were no statistically significant differences between arterial cross-sectional area and arterial wall thickness measurements of the SAH group and SAH + TPM group. These findings demonstrate that TPM has marked neuroprotective effect in an experimental model of SAH in rabbits. This observation may have clinical implications suggesting that this antiepileptic drug could be used as a possible neuroprotective agent in patients without major adverse effects.

Journal of Neurosurgery, 2000

Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia, 2008

The sulcus of the vertebral artery is located behind the lateral mass of the atlas and in some ca... more The sulcus of the vertebral artery is located behind the lateral mass of the atlas and in some cases is converted into a foramen by anomalous ossification known as the posterior ponticulus (osseous bridge). This study involved anatomical observations of 158 isolated anatomical specimens of dry C1 vertebrae. The incidence and types of posterior osseous bridging were identified for the 158 dry samples of atlas vertebrae. In nine (5.6%) dry C1 vertebrae, partial osseous bridging was detected (bilaterally in eight vertebrae and unilaterally on the left in one). Complete osseous bridging (arcuate foramen) was observed in six (3.8%) dry C1 vertebrae (bilaterally in one vertebra, unilaterally on the left in three, and on the right in two). Awareness of the types of posterior osseous bridging of C1 in craniocervical junction surgery is essential, and may be helpful in surgical interventions in this region.

Acta Neurochirurgica, 2007

Background. Though cerebral vasospasm is one of the most serious complications of subarachnoid ha... more Background. Though cerebral vasospasm is one of the most serious complications of subarachnoid haemorrhage (SAH), its complex pathogenesis is poorly understood and available clinical treatment options are unsatisfactory. This study was designed to examine the efficacy of leflunomide, an immunomodulatory agent with inhibitory properties, on vascular smooth muscle cell proliferation and inflammation in a rabbit cerebral vasospasm model.