Publications by authors named "Ali Karadag"

23 Publications

  • Page 1 of 1

The benefits of inferolateral transtubercular route on intradural surgical exposure using the endoscopic endonasal transclival approach.

Acta Neurochir (Wien) 2021 Apr 13. Epub 2021 Apr 13.

Department of Neurosurgery, Microsurgical Neuroanatomy Laboratory, Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey.

Background: Surgical access to the ventral pontomedullary junction (PMJ) can be achieved through various corridors depending on the location and extension of the lesion. The jugular tubercle (JT), a surgically challenging obstacle to access the PMJ, typically needs to be addressed in transcranial exposures. We describe the endoscopic endonasal transclival approach (EETCA) and its inferolateral transtubercular extension to assess the intradural surgical field gained through JT removal. We also complement the dissections with an illustrative case.

Methods: EETCA was surgically simulated, and the anatomical landmarks were assessed in eight cadaveric heads. Microsurgical dissections were additionally performed along the endoscopic surgical path. Lastly, we present an intraoperative video of the trans-JT approach in a patient with lower clival chordoma.

Results: The EETCA allowed adequate extracranial visualization and removal of the JT. The surgical bony window-obtained along the clivus and centered at the JT via the EETCA-measured 11 × 9 × 7 mm. Removal of the JT provided an improved intradural field within the lower third of the cerebellopontine cistern to expose an area bordered by the cranial nerves VII/VIII and flocculus superior and anterior margin of the lateral recess of the fourth ventricle and cranial nerves IX-XI inferiorly, centered on the foramen of Luschka.

Conclusions: Removal of the JT via EETCA improves exposure along the lower third of the cerebellopontine and upper cerebellomedullary cisterns. The inferolateral transtubercular extension of the EETCA provides access to the lateral recess of the fourth ventricle, in combination with the ventral midline pontomedullary region.
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http://dx.doi.org/10.1007/s00701-021-04835-xDOI Listing
April 2021

Microsurgical Management of the Middle Cerebral Artery Bifurcation Aneurysms: An Anatomic Feasibility Study.

ORL J Otorhinolaryngol Relat Spec 2021 Mar 15:1-9. Epub 2021 Mar 15.

Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA.

Background: The proper head positioning decreases the surgical complications by enabling a better surgical maneuverability. Middle cerebral artery (MCA) bifurcation aneurysms have been classified by Dashti et al. [Surg Neurol. 2007 May;67(5):441-56] as the intertruncal, inferior, lateral, insular, and complex types based on dome projection. Our aim was to identify the optimum head positions and to explain the anatomic variables, which may affect the surgical strategy of MCA bifurcation aneurysms.

Methods: The lateral supraorbital approach bilaterally was performed in the 4 cadaveric heads. All steps of the dissection were recorded using digital camera.

Results: The distal Sylvian fissure (SF) dissection may be preferred for insular type and the proximal SF dissection may be preferred for all other types. Fifteen degrees head rotation was found as the most suitable position for the intertruncal, lateral type and subtype of complex aneurysms related with superior trunk. Thirty degrees head rotation was found the most suitable position for the inferior type, insular type, and subtype of complex aneurysms related with inferior trunk.

Conclusions: The head positioning in middle cerebral bifurcation aneurysms surgery is a critical step. It should be tailored according to the projection and its relationship with the parent vessels of the middle cerebral bifurcation.
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http://dx.doi.org/10.1159/000514177DOI Listing
March 2021

Endoscopic endonasal transclival approach to the ventral brainstem: Radiologic, anatomic feasibility and nuances, surgical limitations and future directions.

J Clin Neurosci 2020 Mar 28;73:264-279. Epub 2020 Jan 28.

Department of Neurosurgery, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey.

The endoscopic endonasal transclival approach (EETA) is less invasive than traditional open approaches; however, there is currently limited data on the pre-operative features that may predict success of the EETA. Surgical landmarks and exposure of the EETA and expanded EETA are assessed. We retrospectively measured multiple anatomic features in 154 adult dry skulls, 22 C1 and C2 dry bone vertebrae, and 500 paranasal sinus computed tomography (CT) scans. We also dissected 13 formalin-fixed, silicone-injected adult cadaveric heads. Relevant qualitative and quantitative data were obtained with CT (n = 10) and cadaveric dissection (n = 13). They are expressed as mean (SD), as appropriate and compared with unpaired t tests. Categorical variables were compared with χ tests. We determined the prevalence of clival and sphenoid sinus anatomic variations and assessed potential exposure of the craniovertebral region, based on the relative position of the nasal bone tip, posterior point of the hard palate, and their relation to the position of C1 and C2. Depending on anatomic features, EETA should allow visualization of the ventral brainstem. The mean (SD) dimensions of the surgical window for EETA were 43.2 (5.1) × 18.3 (1.1) mm, in the craniocaudad and horizontal dimensions, respectively. The craniocaudad dimension enlarged to 60.2 (4.7) mm with expanded EETA. The EETA allowed satisfactory exposure for odontoid and C1 anterior arch resection (expanded EETA) in all specimens, regardless of the orientation of the palate. The combination of preoperative radiographic assessment and intraoperative considerations allows safe and effective application and facilitate selection of the most appropriate approach.
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http://dx.doi.org/10.1016/j.jocn.2020.01.012DOI Listing
March 2020

Neuroanatomical Aspects of the Temporo-Parieto-Occipital Junction and New Surgical Strategy to Preserve the Associated Tracts in Junctional Lesion Surgery: Fiber Separation Technique.

Turk Neurosurg 2019 ;29(6):864-874

Ege University, Faculty of Medicine, Department of Neurosurgery, Izmir, Turkey.

Aim: To describe the location of each white matter pathways around the temporo-parieto-occipital junction (TPOJ) and the dissections performed using focal fiber dissection and fiber separation techniques (FST). These areas play an important role in human language processing and high-level brain functions. Thus, it is important to identify the association of the fascicles as well as their courses to plan safe and effective surgical target vectors.

Material And Methods: Thirty formalin-fixed human hemispheres and two formalin-fixed human heads were dissected with focal fiber dissection and FST under 6-40x magnification using a surgical microscope and real-time magnetic resonance imaging navigation system. Two- and three-dimensional anatomical and surgical pictures were obtained and processed using high dynamic range photography (Photomatix) and were correlated to radiological images of the case with glioblastoma of the TPOJ.

Results: The trajectory and connectivity of these fibers as well as their surgical importance in performing FST in cadaver dissections were demonstrated with correlation of the surgical, radiological, and anatomical images.

Conclusion: The microanatomy of the TPOJ and related structures, emphasizing the position of each white matter pathway, has been described. Understanding the composition of each region is critical in preventing intraoperative brain injury that could lead to functional deficits.
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http://dx.doi.org/10.5137/1019-5149.JTN.26200-19.2DOI Listing
February 2020

Anal Extrusion of a Ventriculoperitoneal Shunt.

J Coll Physicians Surg Pak 2019 May;29(5):478-480

Department of Neurosurgery, Tepecik Research and Training Hospital, University of Health Sciences, Izmir, Turkey.

Ventriculoperitoneal shunt (VPS) placement is an effective and most frequently used surgical method in the treatment of hydrocephalus, but the mechanical and infective complications are often seen after this surgical procedure. Bowel perforation after VPS surgery is rarely seen complication that is reported ranging between 0.1% and 0.7% in the literature. We report a case of 10-month baby who was shunted at day three of her life and has presented to us with protruding distal end of the ventricular catheter through anus. Mechanism of migration of VPS is unclarified yet; nevertheless, children with myelomeningocele have weakness of the bowel muscles, which probably makes it more sensitive for perforation. Additionally, sharp and stiff end of the VPS, use of trocar by some surgeons, chronic irritation by the shunt, previous surgery, infection and silicone allergy are other possible reasons of bowel perforation. Peritonitis and ventriculitis have a high morbidity and mortality that may occur after VPS-related bowel perforations; hence, it should be managed rapidly and aggressively to reduce morbidity and mortality.
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http://dx.doi.org/10.29271/jcpsp.2019.05.478DOI Listing
May 2019

Klippel-Trenaunay-Weber Syndrome with Atypical Presentation of Cerebral Cavernous Angioma: A Case Report and Literature Review.

World Neurosurg 2019 Jun 21;126:354-358. Epub 2019 Mar 21.

Department of Radiology, Mayo Clinic, Jacksonville, Florida, USA; Department of Neurologic Surgery, Mayo Clinic, Jacksonville, Florida, USA.

Background: Klippel-Trenaunay-Weber syndrome (KTWS) is a rare syndrome characterized by the triad of cutaneous hemangiomas, venous varicosities, and osseous-soft tissue hypertrophy of the affected limb. Clinical manifestations, genetic testing, and radiologic imaging are the key steps in diagnosing this syndrome.

Case Description: An 18-month-old boy was brought for follow-up brain magnetic resonance imaging (MRI) with a history of right lower limb hypertrophy, cutaneous varicosities, and hemangiomas diagnosed at birth. A baseline MRI at 12 months revealed multiple hemorrhagic lesions within the cerebrum, the largest in the right temporal lobe, which was treated surgically at the age of 18 months because of its rapid growth. This is the youngest patient with KTWS treated surgically for intracranial hemangiomas.

Conclusion: KTWS is a rare disease with a wide range of manifestations. Multisystemic evaluation of this group of patients should be performed to identify cavernous hemangiomas at the early stage of life and adequately treat them in the future. Treatment of KTWS patients with cavernous hemangiomas should not be different from the treatment of patients with any other hemangiomas, and surgical intervention should be considered on a case-to-case bases.
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http://dx.doi.org/10.1016/j.wneu.2019.03.132DOI Listing
June 2019

Hypoxia-Inducible Factor 1α and AT-Rich Interactive Domain-Containing Protein 1A Expression in Pituitary Adenomas: Association with Pathological, Clinical, and Radiological Features.

World Neurosurg 2019 Jan 5;121:e716-e722. Epub 2018 Oct 5.

Department of Pathology, Tepecik Research and Training Hospital, University of Health Sciences, Izmir, Turkey.

Background: Hypoxia-inducible factor (HIF) plays a major role in tumorigenesis and cancer progression. In hypoxic conditions, HIF is upregulated and has been shown to activate multiple genes required for cells to adapt to hypoxia. AT-rich interactive domain-containing protein 1A (ARID1A), a SWI/SNF (switch/sucrose nonfermentable) chromatin remodeling gene has context-dependent tumor-suppressive and oncogenic roles in cancer. We assessed the correlations between the expression and mutations of HIF1A and ARID1A in histopathologically confirmed pituitary adenomas.

Methods: We performed a retrospective analysis of 71 patients who had undergone surgery for pituitary adenoma. Patient demographic, radiological, and histopathological features were correlated with HIF1A and ARID1A expression.

Results: Most cases were HIF1A positive (62%). No significant correlation was found between HIF1A expression and age, gender, tumor size, bone erosion, hemorrhage, or Ki-67 index. An inverse correlation was demonstrated between HIF1A and cavernous sinus invasion (P = 0.035). ARID1A loss was found in 28.2% of pituitary adenomas. No significant correlation was found between ARID1A and any of the assessed variables.

Conclusions: In our patient cohort, we found that most pituitary adenomas expressed HIF1A. To the best of our knowledge, we are the first to assess the presence of ARID1A loss in pituitary adenomas, which occurred in 28.2% of cases. No individual demographic, imaging, or histopathological feature was predictive of ARID1A. Likewise, with the exception of an increased incidence of cavernous sinus invasion, no correlation was found with HIF1A. Given the prognostic value of these markers in other malignancies, their frequency in pituitary adenomas warrants further exploration of their potential role in pituitary adenoma treatment and outcome.
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http://dx.doi.org/10.1016/j.wneu.2018.09.196DOI Listing
January 2019

Superficial Siderosis of the Central Nervous System Due to Recurrent Surgeries of the Thoracic Spine: A Rare Case.

World Neurosurg 2018 Nov 27;119:384-388. Epub 2018 Aug 27.

Department of Neurosurgery, Tepecik Research and Training Hospital, University of Health Sciences, Izmir, Turkey.

Background: Superficial siderosis (SS) of the central nervous system is a rare condition caused by hemosiderin deposition in the subpial layers of the brain and spinal cord. Surgical complications are the primary factor for occurrence of secondary SS. We present a case of SS with an identified bleeding origin in the thoracic spine.

Case Description: A 58-year-old female patient experienced 9 months of continuous progressive dizziness, difficulty with mobilization, drop attacks, and lack of hearing. The patient also had an extensive history of thoracic spinal surgeries. She came to the hospital with gait imbalance. Gradient echo (GE) magnetic resonance imaging (MRI) confirmed hemosiderin deposition along the cerebellar folia and vermis. GE sequences are preferable in this diagnosis, because of higher sensitivity, and for detecting characteristic T2 hypointensity. The dural defect was repaired with an artificial dural patch in thoracal operation area. Clinical findings, imaging studies, intraoperative findings, and literature information are presented.

Conclusions: Performance of an open neurosurgical procedure to repair a dural defect in the presence of MRI confirmed that superficial siderosis is an optimal method and a crucial step to ensure the safe resolution of the condition and to break the circle of emergency admissions of a patient with a dural defect and a history of multiple spinal surgeries.
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http://dx.doi.org/10.1016/j.wneu.2018.08.140DOI Listing
November 2018

Recurrent Osteoma Overlying a Methylmethacrylate Bone Cement Cranioplasty: A Rare Case.

J Coll Physicians Surg Pak 2018 Jun;28(6):S102-S103

Department of Neurosurgery, Saglik Bilimleri University, Tepecik Research and Training Hospital, Izmir, Turkey.

Osteomas are generally benign tumors of the skull that affect all age groups and are diagnosed in the fourth or fifth decade of life, and are rare in childhood. Surgical resection is curative and malignant transformation is very rare. A 12-yearboy who had undergone a craniotomy for resection of a parietal osteoma four years ago, followed by a cranioplasty with methylmethacrylate bone cement, presented to our clinic with an expanding mass overlying the cranioplasty. Upon reoperation, the mass was totally excised, and the parietal cranial defect was repaired using methylmethacrylate bone cement. On histologic examination, the mass was found to be a recurrent osteoma overlying the methylmethacrylate bone cement. In this report, we discuss the etiologies of recurrence of osteoma and treatment options of these rare cases. We believe that this recurrence resulted from contamination of the surgical area and cranioplasty materials with osteoma material. Extensive washing of the cranioplasty materials and perioperative area may prevent recurrence of such tumors.
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http://dx.doi.org/10.29271/jcpsp.2018.06.S102DOI Listing
June 2018

Surgical Management in Cervical Spondylotic Myelopathy Due to Alkaptonuria.

World Neurosurg 2018 May 3;113:308-311. Epub 2018 Mar 3.

Department of Neurosurgery, Saglik Bilimleri University, Tepecik Research and Training Hospital, Izmir, Turkey. Electronic address:

Background: Ochronotic arthropathy related to alkaptonuria is a rare condition. Cervical spine involvement with myelopathic features has been even more rarely described, particularly related to atlantoaxial instability. As such, little is known about the optimal surgical management in these patients.

Case Description: We described the first case, to our knowledge, of a patient with alkaptonuria and related cervical spondylotic myelopathy from pannus formation at the atlantoaxial joint. We describe our choices in surgical management of this rare condition in a patient with an excellent outcome.

Conclusion: Ochronotic cervical spondylotic myelopathy is a rare condition and may require additional considerations in surgical treatment compared to more common causes of cervical spondylotic myelopathy. In our case, we elected for decompression with posterior occipitocervical screw fixation and were able to achieve neurologic recovery with no complications, currently at 2-year follow-up.
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http://dx.doi.org/10.1016/j.wneu.2018.02.148DOI Listing
May 2018

A Rare History: an Intracranial Nail Present for Over a Half-Century.

Acta Medica (Hradec Kralove) 2017;60(3):124-126

Tepecik Research and Training Hospital, Department of Neurosurgery, Izmir, Turkey.

We present a rare case of a patient with a persistent headache for many years found to have an intracranial nail present for nearly 65 years. The nail was found entering approximately 1 cm from the midline on the left side, passing below the superior sagittal sinus, with the tip 1.5 mm right of the frontal horn of the lateral ventricle. Treatment strategies designed to optimize outcome for intracranial foreign bodies and possible complications are discussed in this report. We also discuss the decision for surgical intervention for foreign bodies and the relevance of position of the foreign body.
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http://dx.doi.org/10.14712/18059694.2018.5DOI Listing
April 2018

Neurological recovery after traumatic Cauda Equina syndrome due to glass fragments: An unusual case.

Ulus Travma Acil Cerrahi Derg 2018 Jan;24(1):82-84

Department of Neurosurgery, Health Sciences University, Tepecik Research and Training Hospital, İzmir-Turkey.

Penetrating spinal injuries with foreign bodies are exceedingly rare. To date, pathological problems due to glass fragments in the spinal canal have rarely been reported. In this report, the case presenting with a back laceration, leg pain, and leg weakness was found to have glass frag-ments in the spinal canal at the L2-L3 level by lumbar computed tomography and magnetic resonance imaging. After L2 total laminectomy and retrieval of the glass fragments, the dura was re-paired. The patient was discharged from the hospital after complete neurological recovery. In cases of spinal canal injuries due to foreign bodies, early operative decompression of the neural elements is the treatment of choice. Patients with Cauda Equina syndrome due to glass fragments have a good prognosis for functional recovery.
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http://dx.doi.org/10.5505/tjtes.2017.40583DOI Listing
January 2018

Mammillothalamic and Mammillotegmental Tracts as New Targets for Dementia and Epilepsy Treatment.

World Neurosurg 2018 02 10;110:133-144. Epub 2017 Nov 10.

Department of Neurosurgery, Istanbul University, Cerrahpasa Faculty of Medicine, Istanbul, Turkey.

Background: Recently, neuromodulation through deep brain stimulation (DBS) has appeared as a new surgical procedure in the treatment of some types of dementia and epilepsy. The mammillothalamic and mammillotegmental tracts are involved among the new targets. To our knowledge, a review article focused specifically on these mammillary body efferents is lacking in the medical literature. Their contribution to memory is, regrettably, often overlooked.

Methods: A review of the relevant literature was conducted.

Results: There is evidence that mammillary bodies can contribute to memory independently from hippocampal formation, but the mechanism is not yet known. Recent studies in animals have provided evidence for the specific roles of these mammillary body efferents in regulating memory independently. In animal studies, it has been shown that the disruption of the mammillothalamic tract inhibits seizures and that electrical stimulation of the mammillary body or mammillothalamic tract raises the seizure threshold. In humans, DBS targeting the mammillary body through the mammillothalamic tract or the stimulation of the anterior thalamic nucleus, especially in the areas closely related to the mammillothalamic tract, has been found effective in patients with medically refractory epilepsy. Nonetheless, little knowledge exists on the functional anatomy of the mammillary body efferents, and their role in the exact mechanism of epileptogenic activity and in the memory function of the human brain.

Conclusions: A comprehensive knowledge of the white matter anatomy of the mammillothalamic and mammillotegmental tracts is crucial since they have emerged as new DBS targets in the treatment of various disorders including dementia and epilepsy.
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http://dx.doi.org/10.1016/j.wneu.2017.10.168DOI Listing
February 2018

A Case of Pseudoaneurysm of the Internal Carotid Artery Following Endoscopic Endonasal Pituitary Surgery: Endovascular Treatment with Flow-Diverting Stent Implantation.

Acta Medica (Hradec Kralove) 2017;60(2):89-92

Department of Neurosurgery, Saglik Bilimleri University, Tepecik Research and Training Hospital, Izmir, Turkey.

Internal carotid artery (ICA) pseudoaneurysm is a rare complication of endoscopic endonasal surgery occurring in 0.4-1.1% of cases. Pseudoaneurysms can subsequently result in other complications, such as subarachnoid hemorrhage, epistaxis, and caroticocavernous fistula with resultant death or permanent neurologic deficit. In this case, we illustrate endovascular treatment with a flow-diverting stent for an ICA pseudoaneurysm after endoscopic endonasal surgery for a pituitary adenoma in a 56-year-old male. Surgery was complicated by excessive intraoperative bleeding and emergent CT angiography confirmed an iatrogenic pseudoaneurysm on the anteromedial surface of the ICA. The pseudoaneurysm was treated endovascularly with flow-diverting stent implantation only. Follow-up CT angiography after three months demonstrated occlusion of the pseudoaneurysm.
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http://dx.doi.org/10.14712/18059694.2017.100DOI Listing
June 2018

Primary Sacral Hydatid Cyst Causing Cutaneous Fistula.

J Coll Physicians Surg Pak 2017 May;27(5):311-312

Department of Neurosurgery, Ankara Research and Training Hospital, Ankara, Turkey.

Echinococcus granulosus and Echinococcus multilocularis are the causes of hydatid disease and the main characteristic is endemic. Generally, it affects the liver and lungs. Spinal hydatidosis accounts for less than 1% of the cases. Vertebral hydatidosis is usually silent and a slowly progressive disease with a long latent period. Another rare form is the primary sacral hydatid cyst. Generally, patients suffer from back pain and neural compression symptoms. A 43-year woman was admitted with left leg pain and a fluid leakage from a cutaneous fistula on the left hip. It was diagnosed on MRI as a bilateral cystic lesion which eroded the first sacral wing, extending to the paravertebral region and left intervertebral for a men. We present a case with fluid leakage from cutaneous fistula.
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http://dx.doi.org/2620DOI Listing
May 2017

Fiber Connections of the Supplementary Motor Area Revisited: Methodology of Fiber Dissection, DTI, and Three Dimensional Documentation.

J Vis Exp 2017 05 23(123). Epub 2017 May 23.

Department of Neurosurgery, University of Minnesota.

The purpose of this study is to show the methodology for the examination of the white matter connections of the supplementary motor area (SMA) complex (pre-SMA and SMA proper) using a combination of fiber dissection techniques on cadaveric specimens and magnetic resonance (MR) tractography. The protocol will also describe the procedure for a white matter dissection of a human brain, diffusion tensor tractography imaging, and three-dimensional documentation. The fiber dissections on human brains and the 3D documentation were performed at the University of Minnesota, Microsurgery and Neuroanatomy Laboratory, Department of Neurosurgery. Five postmortem human brain specimens and two whole heads were prepared in accordance with Klingler's method. Brain hemispheres were dissected step by step from lateral to medial and medial to lateral under an operating microscope, and 3D images were captured at every stage. All dissection results were supported by diffusion tensor imaging. Investigations on the connections in line with Meynert's fiber tract classification, including association fibers (short, superior longitudinal fasciculus I and frontal aslant tracts), projection fibers (corticospinal, claustrocortical, cingulum, and frontostriatal tracts), and commissural fibers (callosal fibers) were also conducted.
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http://dx.doi.org/10.3791/55681DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5608134PMC
May 2017

C1 lateral mass screw insertion from the caudal-dorsal to the cranial-ventral direction as an alternate method for C1 fixation: A quantitative anatomical and morphometric evaluation.

J Clin Neurosci 2017 Aug 15;42:176-181. Epub 2017 May 15.

Department of Radiology, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address:

Object: C1 lateral mass screw has been widely used for fixation of the upper cervical spine. However, traditional fixation methods are not without complication. Morphometric measurement of an alternative approach is conducted.

Methods: Three-dimensional CT scans of the cervical spine obtained in 100 adults were evaluated, and key measurements were determined for screw entry points, trajectories, and screw lengths for placement of a C1 screw via this alternate approach. Additional measures were included to account for relevant anatomic variation, including the size of the dangerous lateral zone of the C1 entry point and depth of the atlantooccipital joint surface. Twenty dried atlantal specimens were evaluated to determine corresponding ex vivo measurements.

Results: The mean maximum angle of medialization was 20.8°±2.8° (right) and 21.1°±2.8° (left), as measured in the axial CT images. Sagittal CT images show the mean maximum superior angulation was 24.7°±4.3° (right) and 24°±4.0° (left), and the mean minimum superior angulation was 13.6°±4.4° (right) and 13.6°±3.9° (left). The mean screw length within the lateral mass was 21.2±1.9mm (right) and 21.3±2.0mm (left). Given an additional 10-15mm needed for rod adaptation, an ideal screw length of 30-35mm was determined.

Conclusion: The C1 insertion caudally from the C2 nerve root may become an alternate method. Preoperative consideration of the ideal screw insertion point, trajectory, and length are vital for safe and effective surgical intervention.
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http://dx.doi.org/10.1016/j.jocn.2017.04.041DOI Listing
August 2017

Cortical Bone Trajectory Screw for Lumbar Fixation: A Quantitative Anatomic and Morphometric Evaluation.

World Neurosurg 2017 Jul 3;103:694-701. Epub 2017 May 3.

Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA.

Background: Lumbar cortical bone trajectory (CBT) screw constructs provide an alternative method of pedicle screw fixation in minimally invasive spine surgery. In this study, we explored the CBT technique in further anatomic detail. The primary aims were to evaluate variations in anatomy relevant to CBT screw placement and to determine optimal screw location, trajectory, and length using measures obtained from computed tomography (CT) scans.

Methods: One hundred CT scans of the lumbar spine were reviewed, and 14 total measurements of entry points, trajectories, and lengths for placement of CBT screws were evaluated.

Results: Across all lumbar levels, the mean right pedicle-pars interarticularis junction length ranged from 7.58 ± 1.18 mm to 8.37 ± 1.42 mm, and the mean left pedicle-pars interarticularis junction length ranged from 7.95 ± 1.42 mm to 8.6 ± 1.74 mm. The pedicle-pars interarticularis junction from L1 to L5 was deemed too small for a 5-mm-diameter CBT screw in 35%, 24%, 17%, 17%, and 19%, respectively, on the right, and in 30%, 17%, 17%, 17%, and 20%, respectively, on the left. The average length of a screw placed along the cranial cortical bone of the pedicle ranged from 27 ± 2.5 mm to 30.5 ± 3.4 mm, and the angle of the screw with respect to the vertebral body endplate ranged from 44 ± 4.1° to 48 ± 6.2°.

Conclusions: Improved anatomic knowledge relevant to CBT screw placement for lumbar fixation offers the potential for improving outcomes and reducing complications. Moreover, detailed analysis of the anatomy of the pedicle-pars interarticularis junction via preoperative CT can aid in determining the ideal fixation method.
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http://dx.doi.org/10.1016/j.wneu.2017.03.137DOI Listing
July 2017

Transcortical selective amygdalohippocampectomy technique through the middle temporal gyrus revisited: An anatomical study laboratory investigation.

J Clin Neurosci 2016 Dec 4;34:237-245. Epub 2016 Aug 4.

Department of Neurosurgery, University of Minnesota, Mayo Building, 4th floor 420 Deliware St., SE Minneapolis, MN 55455, USA.

The anterior temporal lobectomy (ATL) and selective amygdalohippocampectomy (SelAH) have been used for surgical treatment of mesial temporal lobe epilepsy. We examined the comprehensive white matter tract anatomy of the temporal lobe to gain an insight into the trans-middle temporal gyrus, a lateral approach which has been commonly used. The transmiddle temporal gyrus approach was performed in a stepwise manner on cadaveric human heads to examine the traversing white matter pathways through it and the structures located in the temporal horn. We reviewed the literature to compare the trans-middle temporal gyrus approach with other SelAH techniques based on surgical outcomes. There does not appear to be a significant difference in seizure outcome between SelAH and ATL. However, the SelAH provides a better neuropsychological outcomes than the ATL in selected patients. Each SelAH approach has individual advantages and disadvantages. Based on our anatomical study, in the transcortical amygdalohippocampectomy technique through the middle temporal gyrus the white matter pathways to be encountered. In the temporal horn, the collateral eminence, hippocampus, lateral ventricular sulcus, choroidal fissure, inferior choroidal point, choroid plexus, fimbria of the fornix, and amygdala are exposed. The subpial dissection is performed along the lateral ventricular sulcus from the collateral eminence on lateral side and from the choroidal fissure on medial side by microdissector for en bloc resection of the hippocampus proper. The trans-middle temporal gyrus approach is commonly used in treatment of mesial temporal lobe epilepsy patients. A better anatomical and functional understanding of the structures of the temporal lobe is crucial for safer and more accurate surgery.
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http://dx.doi.org/10.1016/j.jocn.2016.05.035DOI Listing
December 2016

Microsurgical and Tractographic Anatomy of the Supplementary Motor Area Complex in Humans.

World Neurosurg 2016 Nov 28;95:99-107. Epub 2016 Jul 28.

Department of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA. Electronic address:

Objective: To evaluate the microsurgical anatomy of the fiber tract connections of the supplementary motor area (SMA) and pre-SMA, and examine its potential functional role with reference to clinical trials in the literature.

Methods: Ten postmortem formalin-fixed human brains (20 sides) and 1 cadaveric head were prepared following Klingler's method. The fiber dissection was performed in a stepwise fashion, from lateral to medial and also from medial to lateral, under an operating microscope, with 3D images captured at each stage. Our findings were supported by in vivo magnetic resonance imaging tractography in 2 healthy subjects.

Results: The connections of the SMA complex, composed of the pre-SMA and the SMA proper, are composed of short "U" association fibers and the superior longitudinal fasciculus I, cingulum, claustrocortical fibers, callosal fibers, corticospinal tract, frontal aslant tract, and frontostriatal tract. The claustrocortical fibers may play an important role in the integration of motor, language, and limbic functions of the SMA complex. The frontostriatal tract connects the pre-SMA to the putamen and caudate nucleus, and also forms parts of both the internal capsule and the dorsal external capsule.

Conclusions: The SMA complex has numerous connections throughout the cerebrum. An understanding of these connections is important for presurgical planning for lesions in the frontal lobe and helps explain symptoms related to SMA injury.
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http://dx.doi.org/10.1016/j.wneu.2016.07.072DOI Listing
November 2016

A Cystic Mass does not Always Mean Hydatid Cyst in Endemic Areas.

Eurasian J Med 2014 Feb;46(1):64-6

Department of Pediatric Surgery, Sisli Etfal Training and Research Hospital, Istanbul, Turkey.

Within the medical community, there is a tendency to describe all cystic lesions in the liver and lungs as Hydatid disease (HD) in areas with HD endemics. This approach may sometimes cause a misdiagnosis. We have three cases with children aged between seven, seven and ten year old, all of whom had been diagnosed, via radiologic imaging, with HD cysts and started on treatment without confirmation. The true diagnoses of these cases were undifferentiated embryonal sarcoma (UES) in two and oesophageal duplication in one case, respectively. The indirect haemagglutination assays (IHA) were obtained in two of them. Although their results were negative, albendazole treatment was started in all cases. Confirmatory tests should be run in dubious cases. An IHA test can aid the diagnosis, although its effectiveness is limited. The possibility of false positive and negative results always exists, especially in lung cysts. A percutanous biopsy is strongly advised for differential diagnosis.
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http://dx.doi.org/10.5152/eajm.2014.13DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4261446PMC
February 2014

Classification of percutaneous nephrolithotomy complications using the modified clavien grading system: looking for a standard.

Eur Urol 2008 Jan 24;53(1):184-90. Epub 2007 Jul 24.

Department of Urology, Haseki Teaching and Research Hospital, Istanbul, Turkey.

Objectives: A classification (modified Clavien system) has been proposed to grade perioperative complications. We reviewed our experience with percutaneous nephrolithotomy (PNL), grading the complications according to this new classification.

Methods: A total of 811 PNLs were performed between 2003 and 2006, and charts were retrospectively reviewed focusing on complications observed. According to the modified Clavien classification system, perioperative complications were stratified into five grades. Grade 1 defined all events that, if left untreated, would have a spontaneous resolution or needed a simple bedside intervention. Grade 2 complications required specific medication, including antibiotics and blood transfusion. Grade 3 complications necessitated surgical, endoscopic, or radiologic intervention (3a without general anesthesia, 3b under general anesthesia). Neighboring organ injuries and organ failures were classified as grade 4, and death was considered a grade 5 complication. Kidney stones treated with PNL were also classified as simple and complex and complication rates were compared.

Results: A total of 255 perioperative complications were observed in 237 (29.2%) patients. There were 33 grade 1 (4%), 132 grade 2 (16.3%), 54 grade 3a (6.6%), 23 grade 3b (2.8%), 9 grade 4a (1.1%), and 3 grade 4b (0.3%) complications, and 1 death (0.1%). Most complications were related to bleeding and urine leakage. Grade 2 and 3a complications were significantly more common in patients with complex renal stones.

Conclusions: A graded classification scheme for reporting the complications of PNL may be useful for monitoring and reporting outcomes. However, minor modifications concerning auxiliary treatments are needed and further studies are awaited.
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http://dx.doi.org/10.1016/j.eururo.2007.06.049DOI Listing
January 2008

Congenital lobar emphysema: a clinicopathologic evaluation of 14 cases.

Eur J Pediatr Surg 2003 Apr;13(2):108-11

Department of Paediatric Surgery, Sişli Children's Hospital, Istanbul, Turkey.

Controversy still exists concerning the diagnosis and treatment of congenital lobar emphysema (CLE). Although surgical removal of the affected lobe is the most commonly accepted form of treatment, detection of milder or even asymptomatic cases is usually followed by a more conservative management of patients, i. e. non-surgical treatment and follow-up. We therefore decided to evaluate our patients with CLE, placing special emphasis on treatment and diagnostic techniques. We also evaluated quantitative analyses of alveolar diameters. Fourteen children with CLE were analysed retrospectively, including age, sex, clinical picture, localisation, diagnostic and surgical modalities and histopathologic diagnosis. The alveolar diameters of affected lobes were compared with those of the lobectomised patients with other non-obstructive respiratory diseases. All children but one had severe respiratory distress as an initial symptom. All patients, except newborns, had a history of pulmonary infection. All cases underwent thoracic CT examination as the main radiologic method. In all of the patients, only one lobe was affected. We found an obvious mediastinal shift and atelectasis of adjacent lobes due to compression of the affected lobe. The affected lobe was therefore surgically removed in all of the children. In one case, we had to carry out a partial lobectomy to reduce the duration of the operation, due to an intraoperative fall of oxygen saturation. All of the children had an uneventful clinical course postoperatively. The alveolar diameters of the cases with CLE were significantly greater than those of the control patients. We think that the majority of cases with CLE have too severe respiratory distress to avoid surgical removal of affected lobe. Conservative management should be reserved only for patients with milder symptoms or no distress at all.
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http://dx.doi.org/10.1055/s-2003-39589DOI Listing
April 2003