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Publication Metadata only Posterior Cervical Keyhole Laminoforaminotomy: A Cadaveric Comparative Study to Evaluate Limits of Bony Resection(OXFORD UNIV PRESS INC, 2019) Bayoumi, Ahmed B.; Berk, Selim; Efe, Ibrahim E.; Bas, Elif Gulsah; Duran, Melissa; Yigit, Tolga; Erden, Agin; Kristal, Bruce S.; Kilic, Turker; Konya, Deniz; Toktas, Zafer Orkun; Bahcesehir University; Free University of Berlin; Humboldt University of Berlin; Charite Universitatsmedizin Berlin; Harvard University; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical SchoolBACKGROUND: The posterior cervical keyhole (KH) laminoforaminotomy has been described to involve the lateral portion of cervical laminae of the upper vertebra alone (small KH) or of both upper and lower vertebrae (large KH). OBJECTIVE: To microscopically compare the two keyhole techniques in terms of their ability to expose the corresponding cervical roots. METHODS: Ten cadaveric specimens were operated bilaterally from C3-4 to C6-7 level to expose a total of 80 nerve roots. The large KH was applied to the left side, the small KH to the right side. The maximal length of exposed nerve roots was measured under microscope. The virtual optimal KH surface area was determined using digital software. Each root was inspected for exposure of its root and axilla. RESULTS: The maximal exposed nerve root length on the large KH side was significantly larger than on the small KH side at C3-4, C5-6, and C6-7 levels (P=.031, P=.002, P=.003). No significance was reported for C4-5 (P=.06). We could expose right axillae in (3/40) and left axillae in (33/40, P<.001). Optimal keyhole surface areas were 37.9, 38.2, 38.7, and 46.2 mm(2) in craniocaudal order. CONCLUSION: Large KH defects involving both upper and lower laminae and facets can expose the roots to greater extent than small KHdefects at C3-4, C5-6, and C6-7 levels. Large KH defects may allow better exposure of nerve roots axillae than small KH defects.Publication Metadata only Proposal of a new radiological classification system for spinal meningiomas as a descriptive tool and surgical guide(ELSEVIER, 2017) Bayoumi, Ahmed B.; Laviv, Yosef; Yokus, Burhan; Efe, Ibrahim E.; Toktas, Zafer Orkun; Kilic, Turker; Demir, Mustafa K.; Konya, Deniz; Kasper, Ekkehard M.; Bahcesehir University; Harvard University; Harvard University Medical Affiliates; Beth Israel Deaconess Medical Center; Harvard Medical School; Free University of Berlin; Humboldt University of Berlin; Charite Universitatsmedizin Berlin; Bahcesehir UniversityObjectives: 1) To provide neurosurgeons and radiologists with a new quantitative and anatomical method to describe spinal meningiomas (SM) consistently. 2) To provide a guide to the surgical approach needed and amount of bony resection required based on the proposed classification. 3) To report the distribution of our 58 cases of SM over different Stages and Subtypes in correlation to the surgical treatment needed for each case. 4) To briefly review the literature on the rare non-conventional surgical corridors to resect SM. Patients and methods: We reviewed the literature to report on previously published cohorts and classifications used to describe the location of the tumor inside the spinal canal. We reviewed the cases that were published prior showing non-conventional surgical approaches to resect spinal meningiomas. We proposed our classification system composed of Staging based on maximal cross-sectional surface area of tumor inside canal, Typing based on number of quadrants occupied by tumor and Subtyping based on location of the tumor bulk to spinal cord. Extradural and extra-spinal growth were also covered by our classification. We then applied it retrospectively on our 58 cases. Results: 12 articles were published illustrating overlapping terms to describe spinal meningiomas. Another 7 articles were published reporting on 23 cases of anteriorly located spinal meningiomas treated with approaches other than laminectomies/laminoplasties. 4 Types, 9 Subtypes and 4 Stages were described in our Classification System. In our series of 58 patients, no midline anterior type was represented. Therefore, all our cases were treated by laminectomies or laminoplasties (with/without facetectomies) except a case with a paraspinal component where a costotransversectomy was needed. Conclusion: Spinal meningiomas can be radiologically described in a precise fashion. Selection of surgical corridor depends mainly on location of tumor bulk inside canal.Publication Metadata only Posterior Rigid Instrumentation of C7: Surgical Considerations and Biomechanics at the Cervicothoracic Junction. A Review of the Literature(ELSEVIER SCIENCE INC, 2018) Bayoumi, Ahmed B.; Efe, Ibrahim E.; Berk, Selim; Kasper, Ekkehard M.; Toktas, Zafer Orkun; Konya, Deniz; Bahcesehir University; Free University of Berlin; Humboldt University of Berlin; Charite Universitatsmedizin Berlin; Harvard University; Harvard University Medical Affiliates; Beth Israel Deaconess Medical Center; Harvard Medical SchoolBACKGROUND: The cervicothoracic junction is a challenging anatomic transition in spine surgery. It is commonly affected by different types of diseases that may significantly impair stability in this region. The seventh cervical vertebra (C7) is an atypical cervical vertebra with unique anatomic features compared to subaxial cervical spine (C3 to C6). C7 has relatively broader laminae, larger pedicles, smaller lateral masses, and a long nonbifid spinous process. These features allow a variety of surgical methods for performing posterior rigid instrumentation in the form of different types of screws, such as lateral mass screws, pedicle screws, transfacet screws, and intralaminar screws. Many biomechanical studies on cadavers have evaluated and compared different types of implants at C7. METHODS: We reviewed PubMed/ Medlineby using specific combinations of keywords to summarize previously published articles that examined C7 posterior rigid instrumentation thoroughly in an experimental fashion on patients or cadavers with additional descriptive radiologic parameters for evaluation of the optimum surgical technique for each type. RESULTS: A total of 44 articles were reported, including 22 articles that discussed anatomic considerations (entry points, sagittal and axial trajectories, and features of screws) and another 22 articles that discussed the relevant biomechanical testing at this transitional region if C7 was directly involved in terms of receiving posterior rigid implants. CONCLUSIONS: C7 can accommodate different types of screws, which can provide additional benefits and risks based on availability of bony purchase, awareness of surgical technique, biomechanics, and anatomic considerations.Publication Metadata only Vertebral artery loops in surgical perspective(SPRINGER, 2016) Eksi, Murat Sakir; Toktas, Zafer Orkun; Yilmaz, Baran; Demir, Mustafa Kemal; Ozcan-Eksi, Emel Ece; Bayoumi, Ahmed B.; Yener, Yasin; Akakin, Akin; Konya, Deniz; University of California System; University of California San Francisco; Bahcesehir University; Bahcesehir University; Antalya Ataturk State Hospital; Medical Park Hospitals GroupVertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature. In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases. We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency. Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries.Publication Metadata only Antidepressants in Spine Surgery: A Systematic Review to Determine Benefits and Risks(KOREAN SOC SPINE SURGERY, 2019) Bayoumi, Ahmed B.; Ikizgul, Oyku; Karaali, Ceren Nur; Bozkurt, Selma; Konya, Deniz; Toktas, Zafer Orkun; Bahcesehir University; McMaster University; McMaster University Hospital; Bahcesehir University; Bahcesehir UniversityAntidepressant drugs can be advantageous in treating psychiatric and non-psychiatric illnesses, including spinal disorders. However, spine surgeons remain unfamiliar with the advantages and disadvantages of the use of antidepressant drugs as a part of the medical management of diseases of the spine. Our review article describes a systematic method using the PubMed/Medline database with a specific set of keywords to identify such benefits and drawbacks based on 17 original relevant articles published between January 2000 and February 2018, this provides the community of spine surgeons with available cumulative evidence contained within two tables illustrating both observational (10 studies, three cross-sectional, three case-control, and four cohort studies) and interventional (seven randomized clinical trials) studies. While tricyclic antidepressants (e.g., amitriptyline) and duloxetine can be effective in the treatment of neuropathic pain caused by root compression, venlafaxine may be more appropriate for patients with spinal cord injury presenting with depression and/or nociceptive pain. Despite the potential associated consequences of a prolonged hospital stay, higher cost, and controversial reports regarding the lowering of bone mineral density in the elderly, antidepressants may improve patient satisfaction and quality of life following surgery, and reduce postoperative pain and risk of delirium. The preoperative treatment of preexisting psychiatric diseases, such as anxiety and depression, can improve outcomes for patients with spinal cord injury-related disabilities, however, a preoperative platelet function assay is advocated prior to major spine surgical procedures to protect against significant intraoperative blood loss, as serotonergic antidepressants (e.g., selective serotonin reuptake inhibitors) and bupropion can increase the likelihood of bleeding intraoperatively due to drug-induced platelet dysfunction. This comprehensive review of this evolving topic can assist spine surgeons in better understanding the benefits and risks of antidepressant drugs to optimize outcomes and avoid potential hazards in a spine surgical setting.Publication Metadata only Vertebral artery loops in surgical perspective(Springer Verlag [email protected], 2016) Ekşi̇, Murat Şakir; Toktaş, Zafer Orkun; Yilmaz, Baran; Demir, Mustafa Kemal; Özcan-Ekşi̇, Emel Ece; Bayoumi, Ahmed B.; Yener, Yasin; Akakin, Akin In; Konya, Deniz; Ekşi̇, Murat Şakir, UCSF School of Medicine, San Francisco, United States; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yilmaz, Baran, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Özcan-Ekşi̇, Emel Ece, Department of Physical Medicine and Rehabilitation, Antalya Ataturk State Hospital, Antakya, Turkey; Bayoumi, Ahmed B., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yener, Yasin, Department of Anesthesiology, Medical Park Göztepe Hospital, Istanbul, Turkey; Akakin, Akin In, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyPurpose: Vertebral artery loop is a congenital or acquired anomaly. Vertebral artery loops are incidentally diagnosed during evaluation of neck problems and trauma. We aimed to present the incidence of VA loops using magnetic resonance angiography in consecutive patients and discuss epidemiological data including the gender, age, location, signs and symptoms, treatment approaches and outcomes of VA loops via analyzing literature. Methods: In the first leg of our two-legged study, consecutive patients were evaluated using magnetic resonance angiography to detect any medial loop of vertebral arteries. The study period was from October 2015 to March 2016. In the second leg, academic databases about medial loop of vertebral artery were screened. Case reports, case series, abstracts and references of relevant literature were searched manually to avoid any missing cases. Results: We evaluated 239 consecutive patients using magnetic resonance angiography. Twenty-one patients were excluded from the study due to inadequate image acquisition, aplastic vertebral artery and/or concomitant vertebral artery stenosis. Medial loop of V2 vertebral artery was observed in 13 patients (5.9 %): 9 with left, 2 with right and 2 with bilateral medial V2 loop. Patients with medial V2 loop were significantly older than patients with straight vertebral arteries (70.30 vs. 62.36, p = 0.028). In the literature analysis, VA loops were more commonly observed at V2 segment (90.5 %). Vertebral artery loops were mostly diagnosed at the 5th and 6th decades of life predominantly in females. The most common signs and symptoms were radiculopathy and/or neck pain, and signs and symptoms of vertebrobasilar insufficiency. Conclusions: Concise pre-operative evaluation of the vertebral arteries is essential to avoid the injury of undiagnosed VA loops during surgery, which might result in catastrophic circumstances. Further evaluation of the vertebral arteries using MR angiography is required, especially in elder age, before cervical spine surgeries. © 2017 Elsevier B.V., All rights reserved.Publication Metadata only Proposal of a new radiological classification system for spinal meningiomas as a descriptive tool and surgical guide(Elsevier B.V., 2017) Bayoumi, Ahmed B.; Laviv, Yosef; Yokus, Burhan; Efe, Ibrahim Efecan; Toktaş, Zafer Orkun; Kilic, Turker D.; Demir, Mustafa Kemal; Konya, Deniz; Kasper, Ekkehard Matthias; Bayoumi, Ahmed B., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Laviv, Yosef, Division of Neurosurgery, Harvard Medical School, Boston, United States; Yokus, Burhan, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Efe, Ibrahim Efecan, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey, Department of Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Demir, Mustafa Kemal, Department of Radiology, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kasper, Ekkehard Matthias, Division of Neurosurgery, Harvard Medical School, Boston, United StatesObjectives 1) To provide neurosurgeons and radiologists with a new quantitative and anatomical method to describe spinal meningiomas (SM) consistently. 2) To provide a guide to the surgical approach needed and amount of bony resection required based on the proposed classification. 3) To report the distribution of our 58 cases of SM over different Stages and Subtypes in correlation to the surgical treatment needed for each case. 4) To briefly review the literature on the rare non-conventional surgical corridors to resect SM. Patients and methods We reviewed the literature to report on previously published cohorts and classifications used to describe the location of the tumor inside the spinal canal. We reviewed the cases that were published prior showing non-conventional surgical approaches to resect spinal meningiomas. We proposed our classification system composed of Staging based on maximal cross-sectional surface area of tumor inside canal, Typing based on number of quadrants occupied by tumor and Subtyping based on location of the tumor bulk to spinal cord. Extradural and extra-spinal growth were also covered by our classification. We then applied it retrospectively on our 58 cases. Results 12 articles were published illustrating overlapping terms to describe spinal meningiomas. Another 7 articles were published reporting on 23 cases of anteriorly located spinal meningiomas treated with approaches other than laminectomies/laminoplasties. 4 Types, 9 Subtypes and 4 Stages were described in our Classification System. In our series of 58 patients, no midline anterior type was represented. Therefore, all our cases were treated by laminectomies or laminoplasties (with/without facetectomies) except a case with a paraspinal component where a costotransversectomy was needed. Conclusion Spinal meningiomas can be radiologically described in a precise fashion. Selection of surgical corridor depends mainly on location of tumor bulk inside canal. © 2018 Elsevier B.V., All rights reserved.Publication Metadata only Posterior Rigid Instrumentation of C7: Surgical Considerations and Biomechanics at the Cervicothoracic Junction. A Review of the Literature(Elsevier Inc. [email protected], 2018) Bayoumi, Ahmed B.; Efe, Ibrahim Efecan; Berk, Selim; Kasper, Ekkehard Matthias; Toktaş, Zafer Orkun; Konya, Deniz; Bayoumi, Ahmed B., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Efe, Ibrahim Efecan, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey, Department of Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany; Berk, Selim, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kasper, Ekkehard Matthias, Division of Neurosurgery, Harvard Medical School, Boston, United States; Toktaş, Zafer Orkun, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyBackground: The cervicothoracic junction is a challenging anatomic transition in spine surgery. It is commonly affected by different types of diseases that may significantly impair stability in this region. The seventh cervical vertebra (C7) is an atypical cervical vertebra with unique anatomic features compared to subaxial cervical spine (C3 to C6). C7 has relatively broader laminae, larger pedicles, smaller lateral masses, and a long nonbifid spinous process. These features allow a variety of surgical methods for performing posterior rigid instrumentation in the form of different types of screws, such as lateral mass screws, pedicle screws, transfacet screws, and intralaminar screws. Many biomechanical studies on cadavers have evaluated and compared different types of implants at C7. Methods: We reviewed PubMed/Medline by using specific combinations of keywords to summarize previously published articles that examined C7 posterior rigid instrumentation thoroughly in an experimental fashion on patients or cadavers with additional descriptive radiologic parameters for evaluation of the optimum surgical technique for each type. Results: A total of 44 articles were reported, including 22 articles that discussed anatomic considerations (entry points, sagittal and axial trajectories, and features of screws) and another 22 articles that discussed the relevant biomechanical testing at this transitional region if C7 was directly involved in terms of receiving posterior rigid implants. Conclusions: C7 can accommodate different types of screws, which can provide additional benefits and risks based on availability of bony purchase, awareness of surgical technique, biomechanics, and anatomic considerations. © 2018 Elsevier B.V., All rights reserved.Publication Metadata only Posterior cervical keyhole laminoforaminotomy: A cadaveric comparative study to evaluate limits of bony resection(Oxford University Press, 2019) Bayoumi, Ahmed B.; Berk, Selim; Efe, Ibrahim Efecan; Baş, Elif Gülşah; Duran, Melissa; Yigit, Tolga; Erden, Agin; Kristal, Bruce S.; Kilic, Turker D.; Konya, Deniz; Bayoumi, Ahmed B., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey, Faculty of Medicine, Bahçeşehir Üniversitesi, Istanbul, Turkey; Berk, Selim, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Efe, Ibrahim Efecan, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey, Department of Neurosurgery, Charité – Universitätsmedizin Berlin, Berlin, Germany; Baş, Elif Gülşah, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Duran, Melissa, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Yigit, Tolga, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Erden, Agin, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Kristal, Bruce S., Department of Medicine, Brigham and Women's Hospital, Boston, United States, Department of Medicine, Harvard Medical School, Boston, United States; Kilic, Turker D., Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, Turkey; Konya, Deniz, Department of Neurosurgery, Bahçeşehir Üniversitesi, Istanbul, TurkeyBACKGROUND: The posterior cervical keyhole (KH) laminoforaminotomy has been described to involve the lateral portion of cervical laminae of the upper vertebra alone (small KH) or of both upper and lower vertebrae (large KH). OBJECTIVE: To microscopically compare the two keyhole techniques in terms of their ability to expose the corresponding cervical roots. METHODS: Ten cadaveric specimens were operated bilaterally from C3-4 to C6-7 level to expose a total of 80 nerve roots. The large KH was applied to the left side, the small KH to the right side. The maximal length of exposed nerve roots was measured under microscope. The virtual optimal KH surface area was determined using digital software. Each root was inspected for exposure of its root and axilla. RESULTS: The maximal exposed nerve root length on the large KH side was significantly larger than on the small KH side at C3-4, C5-6, and C6-7 levels (P = .031, P = .002, P = .003). No significance was reported for C4-5 (P = .06). We could expose right axillae in (3/40) and left axillae in (33/40, P < .001). Optimal keyhole surface areas were 37.9, 38.2, 38.7, and 46.2 mm2 in craniocaudal order. CONCLUSION: Large KH defects involving both upper and lower laminae and facets can expose the roots to greater extent than small KH defects at C3-4, C5-6, and C6-7 levels. Large KH defects May allow better exposure of nerve roots axillae than small KH defects. © 2021 Elsevier B.V., All rights reserved.