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Öğe Beyond nimodipine: advanced neuroprotection strategies for aneurysmal subarachnoid hemorrhage vasospasm and delayed cerebral ischemia(Springer, 2024) Luzzi, Sabino; Bektaşoğlu, Pınar Kuru; Doğruel, Yücel; Güngör, AbuzerThe clinical management of aneurysmal subarachnoid hemorrhage (SAH)-associated vasospasm remains a challenge in neurosurgical practice, with its prevention and treatment having a major impact on neurological outcome. While considered a mainstay, nimodipine is burdened by some non-negligible limitations that make it still a suboptimal candidate of pharmacotherapy for SAH. This narrative review aims to provide an update on the pharmacodynamics, pharmacokinetics, overall evidence, and strength of recommendation of nimodipine alternative drugs for aneurysmal SAH-associated vasospasm and delayed cerebral ischemia. A PRISMA literature search was performed in the PubMed/Medline, Web of Science, ClinicalTrials.gov, and PubChem databases using a combination of the MeSH terms "medical therapy," "management," "cerebral vasospasm," "subarachnoid hemorrhage," and "delayed cerebral ischemia." Collected articles were reviewed for typology and relevance prior to final inclusion. A total of 346 articles were initially collected. The identification, screening, eligibility, and inclusion process resulted in the selection of 59 studies. Nicardipine and cilostazol, which have longer half-lives than nimodipine, had robust evidence of efficacy and safety. Eicosapentaenoic acid, dapsone and clazosentan showed a good balance between effectiveness and favorable pharmacokinetics. Combinations between different drug classes have been studied to a very limited extent. Nicardipine, cilostazol, Rho-kinase inhibitors, and clazosentan proved their better pharmacokinetic profiles compared with nimodipine without prejudice with effective and safe neuroprotective role. However, the number of trials conducted is significantly lower than for nimodipine. Aneurysmal SAH-associated vasospasm remains an area of ongoing preclinical and clinical research where the search for new drugs or associations is critical.Öğe Clival dural reconstruction via transnasal approaches:fat graft fixation technique(American Association of Neurological Surgeons, 2025) Luzzi, Sabino; Doğruel, Yücel; Güngör, Abuzer; Gürses, Muhammet Enes; Rahmanov, Serdar; Türe, Hatice; Türe, UğurOBJECTIVE CSF fistulas are the weak spots of transnasal endoscopic and microsurgical skull base approaches. An autologous fat graft is considered the best substrate for clival dural reconstruction via transnasal approaches. However, potential gravitational displacement of the graft may result in CSF leakage. The authors have developed and described herein the fat graft fixation (FGF) technique to secure the fat graft against dislocation after transclival resection of chor- domas invading the dura. METHODS Seventy-five patients with cranial chordomas underwent surgical treatment at the authors’ institution from September 2006 through June 2023. Of these, the authors collected demographic, clinical, radiological, surgical, and outcome data from 34 patients who underwent an endoscope-assisted microsurgical transclival approach via a transna- sal, sublabial, or sublabial transmaxillary extended corridor. The FGF reconstruction technique was progressively imple- mented to improve clival reconstruction, with a focus on the results. With a custom-made 8-mm 3/8 round atraumatic surgical suture needle, a 4/0 Vicryl stitch was placed through the adjacent dural borders. An abdominal autologous fat graft was then placed over the dural defect. One triple knot was tied to secure the graft and prevent its delayed gravita- tional displacement. The primary outcome was to determine if the FGF group had a higher rate of early or late oronasal CSF fistula compared to the unlocked free graft group. Secondary outcomes included tension pneumocephalus, surgical site infection, and meningitis. RESULTS The fat graft was not used in 8 (23.5%) of the 34 patients because the dura was intraoperatively intact. The unlocked free graft and FGF techniques were used in 20 (58.8%) and 6 (17.6%) patients, respectively. Of the 34 patients, no fistulas were observed in the group treated with the FGF technique, while 4 fistulas were found in the unlocked free graft group (p < 0.05), with 2 of these cases involving meningitis. Patients with a CSF fistula underwent a total of 7 surgi- cal procedures: 3 revision surgical procedures, 2 lumboperitoneal shunts, and 2 ventriculoperitoneal shunts. CONCLUSIONS In the authors’ preliminary experience, the FGF technique has shown promise in eliminating the risk of CSF fistula and other related complications after the transclival approach for clival chordomas involving the dura.https://thejns.org/doi/abs/10.3171/2024.11.FOCUS24560 ©AANS 2025, except where prohibited by US copyright law.Öğe Creating a neuroanatomy education model with augmented reality and virtual reality simulations of white matter tract(874, 2024) Gürses, Muhammet Enes; Gökalp, Elif; Gecici, Neslihan Nisa; Güngör, Abuzer; Berker, Mustafa; Ivan, Michael E.; Komotar, Ricardo J.; Cohen-Gadol, Aaron A.; Türe, UǧurOBJECTIVE The utilization of digital technologies has experienced a notable surge, particularly in cases where access to cadavers is constrained, within the context of practical neuroanatomy training. This study evaluates augmented reality (AR)- and virtual reality (VR)-based educational models for neuroanatomy education. METHODS Three-dimensional models were created using advanced photogrammetry. VR- and AR-based educational models were developed by arranging these 3D models to align with the learning objectives of neurosurgery residents and second-year medical students whose cadaveric training was disrupted due to an earthquake in Turkey. Participants engaged with and evaluated the VR- and AR-based educational models, followed by the completion of a 20-item graded user experience survey. A 10-question mini-test was given to assess the baseline knowledge level prior to training and to measure the achievement of learning objectives after training. RESULTS Forty neurosurgery residents were trained with a VR-based educational model using VR headsets. An AR-based educational model was provided online to 200 second-year medical students for their practical neuroanatomy lesson. The average correct answer rates before the training were 7.5/10 for residents and 4.8/10 for students. These rates were significantly improved after the training to 9.7/10 for residents and to 8.7/10 for students (p < 0.001). Feedback from the users concurred that VR- and AR-based training could significantly enhance the learning experience in the field of neuroanatomy. CONCLUSIONS VR/AR-based educational models have the potential to improve education. VR/AR-based training systems can serve as an auxiliary tool in neuroanatomy training, offering a realistic alternative to traditional learning tools. © AANS 2024.Öğe External Auditory Canal Transillumination-Guided Middle Fossa Approaches: An Anatomical Feasibility Study(Lippincott Williams and Wilkins, 2025) Şahin, Mustafa; Güngör, Abuzer; Doǧruel, Yücel; Luzzi, Sabino; Yılmaz, Adem; Türe, UğurBACKGROUND AND OBJECTIVES: The middle fossa approaches are tremendously versatile for treating small vestibular schwannomas, selected petroclival meningiomas, midbasilar trunk aneurysms, and lesions of the petrous bone. Our aim was to localize the internal acoustic canal and safely drill the petrous apex with these approaches. This study demonstrates a new method to locate the internal acoustic canal during surgery in the middle fossa. METHODS: The microsurgical anatomy of the middle fossa floor was studied in 11 formalin-fixed and silicone-injected cadaveric heads. Extradural dissection of the skull base was completed from the posterior to the anterior side. A zero-degree rigid endoscope was inserted perpendicularly into the external auditory canal. The light beam was first directed through the tympanic membrane, avoiding injury to the tympanic membrane. The room lights were dimmed to provide a clearer view of the transilluminated bony area. Drilling was performed with transillumination guidance. RESULTS: The transilluminated area included the tympanic and mastoid tegmen up to the arcuate eminence. The nonilluminated area was bounded posteriorly by the arcuate eminence, laterally by the greater superficial petrosal nerve, and posteromedially by the petrous ridge. In all specimens, drilling the transition line between the Kawase triangle and the transilluminated area unroofed the internal auditory canal (IAC). No transillumination of the carotid canal was seen after anterior petrosectomy in any of the specimens. The entire contents of the IAC were preserved in both anterior petrosectomy and unroofing of the IAC. CONCLUSION: In this anatomical study, transillumination of the external auditory canal proved to be feasible, accurate, and safe in guiding the middle fossa approaches. The ease of implementation and cost-effectiveness of the technique may suggest a possible application in operative scenarios. © Congress of Neurological Surgeons 2025. All rights reserved.Öğe Human adapted prosomeric model: a future for brainstem tumor classification(Elsevier, 2024) Munoz-Gualan, Alberth Patricio; Güngör, Abuzer; Cezayirli, Phillip Cem; Rahmanov, Serdar; Gürses, Muhammet Enes; Puelles, Luis; Türe, UğurThis study reevaluates the conventional understanding of midbrain anatomy and neuroanatomical nomenclature in the context of recent genetic and anatomical discoveries. The authors assert that the midbrain should be viewed as an integral part of the forebrain due to shared genetic determinants and evolutionary lineage. The isthmo-mesencephalic boundary is recognized as a significant organizer for both the caudal midbrain and the isthmo-cerebellar area. The article adopts the prosomeric model, redefining the whole brain as neuromeres, offering a more precise depiction of brain development, including processes like proliferation, neurogenesis, cell migration, and differentiation. This shift in understanding challenges traditional definitions of the midbrain based on external brain morphology. The study also delves into the historical context of neuroanatomical models, including the columnar model proposed by Herrick in 1910, which has influenced our understanding of brain structure. Furthermore, the study has clinical implications, affecting neuroanatomy, neurodevelopmental studies, and the diagnosis and treatment of brain disorders. It emphasizes the need to integrate molecular research into human neuroanatomical studies and advocates for updating neuroanatomical terminology to reflect modern genetic and molecular insights. The authors propose two key revisions. First, we suggest reclassifying the isthmo-cerebellar prepontine region as part of the hindbrain, due to its role in cerebellar development and distinct location caudal to the genetically-defined midbrain. Second, we recommend redefining the anterior boundary of the genetically-defined midbrain to align with genetic markers. In conclusion, the authors highlight the importance of harmonizing neuroanatomical nomenclature with current scientific knowledge, promoting a more precise and informed understanding of brain structure, which is crucial for both research and clinical applications related to the human brain.Öğe Medical management of chronic subdural hematoma with low-dose hydrocortisone: a case series(Springer Science and Business Media Deutschland GmbH, 2024) Gürses, Muhammet Enes; Ülgen, Meriç; Gökalp, Elif; Gecici, Neslihan Nisa; Güngör, Abuzer; Türe, Hatice; Türe, UğurChronic subdural hematomas (cSDH) are often managed with a burr-hole craniostomy and drainage, but surgery is associated with elevated mortality, morbidity, and recurrence. Despite reports of steroid use for such patients, its efficacy and feasibility are still debated. We present our patient series treated with low-dose hydrocortisone. We retrospectively reviewed data from patients treated with hydrocortisone between 2017 and 2023. Demographics, clinical and radiological data were collected. Of 27 patients identified, nine required a burr-hole craniotomy for an average volume of 120.23 cm3, average midline shift of 9 mm, and neurological deficits. Eighteen met the criteria for inclusion. The mean age was 78.5 years; 13 were male. None had severe symptoms requiring urgent intervention. Except for one with a Karnofsky Performance Scale score of 70, all could maintain normal activity before treatment. The mean baseline volume was 52.6 cm3. Midline shift, present in six, averaged 6.8 mm. Patients underwent treatment for an average of 5.15 months. Nine had complete resolution within 3 months, while nine required longer treatment, including one who needed 9 months for a re-bleed after a fall. Paired t-tests indicated significant reductions in hematoma volumes at the second week (p = 0.01), first month (p < 0.0001), and third month (p < 0.0001) of treatment. No complications occurred and the post-treatment Karnofsky scores ranged from 90 to 100. Treatment for cSDH should be tailored to the patient. Low-dose hydrocortisone is safe and effective in asymptomatic patients, those with mild to moderate symptoms, and those who are either unsuitable for or decline surgical intervention. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Öğe Microsurgical Resection of a PediatricTegmentum Tumor Through the Paramedian Supracerebellar Transtentorial Approach with the Tentorial Cut Technique: 2-Dimensional Operative Video(Lippincott Williams and Wilkins, 2024) Rahmanov, Serdar; Doǧruel, Yücel; Güngör, Abuzer; Türe, UǧurThe brainstem contains a highly complex group of nuclei and major white matter tracts within a small volume.1 The complex nature of its anatomy creates challenges for surgery in this area, impeding the standardization of approaches. Therefore, the concept of the "safe entry zone" should be considered with caution, and the strategy for each patient should be tailored based on the relevant subunit of the brainstem and individual patient characteristics. The critical parameter to target in patients is achieving the highest possible extent of resection while preserving function.1 The paramedian supracerebellar transtentorial approach is usually suitable for midbrain lesions. This approach allows for targeting tegmental tumors through the posterolateral midbrain surface.1 It is typically performed through a paramedian suboccipital craniotomy, ideally with the patient in the semisitting position, and is now considered a standard and safe approach.2 In patients with a spontaneous atrial right-to-left shunt, lateral or semilateral positions are viable alternatives, with the semilateral preferred for intraoperative magnetic resonance imaging.1 The cerebellar hemispheric tentorial bridging veins are usually located in the surgical route, narrowing the surgical corridor.3 Sacrifice or unintended rupture of these veins can sometimes lead to unexpected serious complications. Therefore, it is essential to preserve these veins during supracerebellar approaches.3 In this study, we demonstrate the resection of a pediatric tegmentum tumor through the left-sided paramedian supracerebellar transtentorial approach. In addition, we show the tentorial cut technique used to preserve the cerebellar hemispheric tentorial bridging veins. The patient's parents consented to the procedure and to the publication of his image. © 2024 Lippincott Williams and Wilkins. All rights reserved.Öğe Neglected tracts of the brainstem: transverse peduncular tract of Gudden and taenia pontis(American association of neurological surgeons, 2024) Rahmanov, Serdar; Güngör, Abuzer; Gülsuna, Beste; Munoz-Gualan, Alberth PatricioOBJECTIVE The anatomy and function of the brainstem have fascinated scientists for centuries; however, the brain- stem remains one of the least studied regions of the human brain. As the authors delved into studying this structure, they observed a growing tendency to forget or neglect previously identified structures. The aim of this study was to describe two such structures: the transverse peduncular tract, also known as the Gudden tract, and the taenia pontis. The authors analyzed the potential effects of neglecting these structures during brainstem surgery and the implications for clinical practice. METHODS After removal of the arachnoid and vascular structures, 20 human brainstem specimens were frozen and stored at -16 degrees C degrees C for 2 weeks, according to the method described by Klingler. The specimens were then thawed and dissected with microsurgical techniques. The results of microsurgical fiber dissection at each step were photographed. RESULTS This study revealed two previously neglected or forgotten structures within the brainstem. The first is the transverse peduncular tract of Gudden, which arises from the brachium of the superior colliculus. This tract follows an arcuate course along the lateral and ventral surfaces of the midbrain, perpendicular to the cerebral peduncle, and terminates in the nuclei of the transverse peduncular tract within the interpeduncular fossa. The second structure is the taenia pontis, which originates contralaterally in the interpeduncular fossa. It becomes visible at the level of the pontomesencephalic sulcus and extends to the base of the lateral mesencephalic sulcus, where it divides into several thin bundles. Along the interpeduncular sulcus, between the superior and middle cerebellar peduncles, it reaches the parabrachial recess and enters the cerebellum. CONCLUSIONS Recently, with increasing understanding and expertise in brainstem research, surgical approaches to this area have become more common, emphasizing the importance of a detailed knowledge of the brainstem. The two structures mentioned in this paper are described in history books and were widely studied in the 19th century but have not been mentioned in modern literature. The authors propose that a deeper understanding of these structures may prove valuable in neurosurgical practice and help reduce patient comorbidity.Öğe Selective amygdalohippocampectomy via the paramedian supracerebellar-transtentorial approach for mediobasal temporal epilepsy(American association of neurological surgeons, 2024) Doğruel, Yücel; Rahmanov, Serdar; Güngör, Abuzer; Türe, UğurSelective amygdalohippocampectomy via the pterional transsylvian approach is a feasible option for many patients with mediobasal temporal epilepsy. However, it may be insufficient for patients when the posterior hippocampal region is involved. The paramedian supracerebellar transtentorial approach offers precise anatomical orientation when expos-ing the entire length of the mediobasal temporal region, including the fusiform gyrus. In addition, this approach allows selective amygdalohippocampectomy without any neocortical damage. This video presents the successful treatment of a patient with posterior hippocampal sclerosis and mediobasal temporal epilepsy through the paramedian supracerebellar transtentorial approach.Öğe Sublabial transmaxillary approach to the inferior aspect of the orbit(American Association of Neurological Surgeons, 2025) Doǧruel, Yücel; Güngör, Abuzer; Türe, Hatice; Türe, UǧurOBJECTIVE The objective was to demonstrate the surgical steps and outcomes of the sublabial transmaxillary microsurgical approach with endoscopic assistance to treat lesions in the inferior aspect of the orbit, as well as to describe the use of patient-specific 3D models to facilitate surgical preparation and improve experience with the technique. METHODS The authors' study evaluated data from patients who underwent an endoscope-assisted sublabial transmaxillary approach for inferior orbital lesions. For 2 patients, 3D models were created for preoperative planning and assessment of the approach. Surgical steps comprised osteotomy to access the maxillary sinus, bony resection of the orbital floor, opening of the periorbital fascia, and dissecting and removing the lesion, followed by closure. The neuroendoscope was used to inspect the surgical cavity between each step. RESULTS The study included 5 patients with varying visual field defects and proptosis who underwent the sublabial transmaxillary microsurgical approach with endoscopic assistance. Complete resection was achieved in all, and all patients reported improvement in visual field defects and proptosis after the procedure. No complications were observed except for transient unilateral maxillary edema noted around the incision site in 3 patients during the early postoperative period, which resolved within a few days. Histopathological examination confirmed the diagnosis of cavernous malformation in all patients. CONCLUSIONS The sublabial transmaxillary approach is a direct and safe method to resect cavernous malformations at the inferior aspect of the orbit. It reduces the risk of complications associated with lateral, transcranial, and transnasal approaches that may cross critical structures. The microsurgical approach provides the benefit of two-handed dissection for lesions embedded in orbital fat, which can be challenging because of adhesions to surrounding tissues. The use of 3D models can facilitate surgical planning and enhance familiarity with the approach. © AANS 2025.Öğe The supracerebellar suprapineal approach: a novel method to separate cadaveric brain hemispheres and preserve the midline structures(Kare publishing, 2024) Munoz-Gualan, Alberth Patricio; Güngör, Abuzer; Romano-Albornoz, Monica; Gürses, Muhammet Enes; Elias, Çimen; Topçam, Arda; Ramanov, Serdar; Türe, UğurObjectives: To describe a novel technique for dissecting cadaver brains without damaging medial brain structures and surfaces, ensuring preservation for neuroanatomical study and training. Methods: Ten adult cadaveric brains were dissected using the supracerebellar suprapineal approach under an operative microscope with 6x to 40x magnification. This approach allowed for the separation of the brain into two hemispheres while providing direct visualization of the third ventricle and preserving midline structures. Results: The supracerebellar suprapineal approach enabled accurate and feasible dissection of the hemispheres without causing damage to the medial brain structures. All midline structures, including the third ventricle, were preserved, producing high-quality specimens for anatomical study. Conclusion: The supracerebellar suprapineal approach offers a significant advancement in the technique for hemispheric brain dissection, ensuring the preservation of medial brain structures and providing superior specimens for neurosurgical training and study.Öğe Thrombosed posterior inferior cerebellar artery aneurysm mimicking a medulla oblongata cavernous malformation: 2-dimensional operative video(Lippincott williams & wilkins, 2024) Doğruel, Yücel; Rahmanov, Serdar; Güngör, Abuzer; Türe, UğurThe incidence of posterior inferior cerebellar artery (PICA) aneurysms is estimated to be between 0.5% and 3% of total aneurysm cases.(1) Most patients with these aneurysms typically present with subarachnoid hemorrhage, although there are instances in which patients may present with symptoms resulting from mass effect exerted on the brain stem or lower cranial nerves.(1,2) Treatment options for PICA aneurysms include endovascular procedures, surgical clipping, or bypass techniques.(2) Surgical treatment is considered more effective for partially thrombosed aneurysms compared with endovascular approaches.(3) In addition, endovascular coiling of these aneurysms carries the potential risk of coilmigration and subsequent reopening of the aneurysm lumen.(4) In certain instances, thrombosed PICA aneurysms have the potential to simulate the radiological characteristics of alternative pathologies, such as cavernous malformations or brainstem tumors.(5-7) This situation can result in misdiagnosis and inappropriate management. We present the case of a patient who exhibited symptoms of imbalance and dysfunction in the lower cranial nerves. Magnetic resonance imaging findings indicated a possible cavernous malformation in the medulla oblongata. However, further investigation revealed that the underlying cause was a thrombosed PICA aneurysm. The patient was successfully treated through surgical clipping.Öğe Virtual anatomical atlas of the deep brain nuclei(Springer science and business media deutschland GmbH, 2024) Sevgi, Umut Tan; Güngör, Abuzer; Erol, Gökberk; Canbolat, Çağrı; Middlebrooks, Erik H.; Sönmez, Osman Fikret; Doğruel, Yücel; Türe, UğurThis study aims to improve understanding of the anatomy of the deep brain nuclei relevant to deep brain stimulation as well as stereotactic lesioning procedures, including radio frequency, high-focused ultrasound, and radiosurgery. We created interactive, three-dimensional virtual models from cadaveric dissections and radiological segmentation. We used five brain specimens (ten hemispheres) obtained from routine autopsies, prepared according to Klingler's method. Dissections were done from lateral to medial, medial to lateral, and superior to inferior to expose deep brain stimulation targets and adjacent structures. Using photogrammetry, we scanned the specimens to create detailed three-dimensional models. These models were uploaded to an online platform for free global access. Radiological models were also generated from atlas-based regions using the Montreal Neurological Institute template. We produced 16 high-quality cadaveric models at various stages of dissection. These and the radiological models were examined and interacted with through augmented reality and virtual reality headsets. This approach allowed comprehensive visual access to the anatomical structures and delineated their spatial relationships. These three-dimensional models provide detailed anatomical representations that can enhance anatomical orientiation, improve spatial perception, and serve as valuable educational tools for clinicians and students.
