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Yamaguchi I, Kanematsu Y, Shimada K, Yamamoto N, Korai M, Miyake K, Miyamoto T, Sogabe S, Shikata E, Ishihara M, Yamamoto Y, Kuroda K, Takagi Y. Evaluation of Serial Intra-Arterial Indocyanine Green Videoangiography in the Surgical Treatment of Cranial and Craniocervical Junction Arteriovenous Fistulae: A Case Series. Oper Neurosurg (Hagerstown) 2023; 25:292-300. [PMID: 37345942 DOI: 10.1227/ons.0000000000000796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 04/20/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Intravenous indocyanine green (IV-ICG) videoangiography is commonly performed to detect blood flow in the microscopic view. However, intra-arterial ICG (IA-ICG) videoangiography provides high-contrast imaging, repeatability within a short period of time, and clear-cut separation of the arterial and venous phases compared with IV-ICG. These features are useful for detecting retrograde venous drainage (RVD) and shunt occlusion in arteriovenous fistulae (AVF) surgery. This study aimed to investigate whether IA-ICG videoangiography can be repeatable within a short period of time and be useful for detecting RVD and shunt occlusion in cranial- and craniocervical junction (CCJ)-AVF surgery. METHODS Between January 2012 and December 2022, 50 patients were treated with endovascular or surgical intervention for cranial- and CCJ-AVF at Tokushima University Hospital. Of these, 5 patients (6 lesions) underwent open surgery with IA-ICG videoangiography in a hybrid operating room. We analyzed the data of these 5 patients (6 lesions). RESULTS There were 4/patient (median, range 2-12) and 3.5/lesion (median, range 2-10) intraoperative IA-ICG runs. IA-ICG videoangiography detected RVD in all patients. Clearance of IA-ICG-induced fluorescence was achieved within 30 seconds in all patients at each region of interest. After the disconnection of the fistulae, IA-ICG videoangiography and intraoperative digital subtraction angiography (DSA) confirmed the disappearance of RVD in all patients. There were no complications associated with IA-ICG videoangiography. CONCLUSION This study showed that IA-ICG videoangiography is repeatable within a short period of time before and after obliteration and can be useful for detecting RVD and shunt occlusion in cranial- and CCJ-AVF surgery. IA-ICG videoangiography also allows intraoperative DSA studies in a hybrid operating room. Considering the recent advancements in hybrid operating rooms, combining IA-ICG videoangiography with intraoperative DSA is a useful strategy for cranial- and CCJ-AVF surgery.
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Affiliation(s)
- Izumi Yamaguchi
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Yasuhisa Kanematsu
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Kenji Shimada
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Nobuaki Yamamoto
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Masaaki Korai
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Kazuhisa Miyake
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Takeshi Miyamoto
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Shu Sogabe
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Eiji Shikata
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Manabu Ishihara
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Yuki Yamamoto
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Kazutaka Kuroda
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Yasushi Takagi
- Department of Neurosurgery, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
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Vivanco-Suarez J, Sioutas GS, Matache IM, Muhammad N, Salem MM, Kandregula S, Jankowitz BT, Burkhardt JK, Srinivasan VM. Intraoperative angiography during neurosurgical procedures on patients in prone, three-quarters prone, and park-bench positions: tertiary single-center experience with systematic review and meta-analysis. J Neurointerv Surg 2023:jnis-2022-020035. [PMID: 37068942 DOI: 10.1136/jnis-2022-020035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/25/2023] [Indexed: 04/19/2023]
Abstract
BACKGROUND There is limited evidence about the role and effectiveness of intraoperative angiography (IOA) during neurosurgical procedures with patients in prone, three-quarters prone, and park-bench positions. OBJECTIVE To carry out a systematic review and meta-analysis of the literature to evaluate the safety and efficacy of IOA during neurosurgical procedures. METHODS We reviewed (between January 1960 and July 2022) all studies in which IOAs were performed during neurosurgical procedures with patients in either prone, three-quarters prone, or park-bench positions. Additionally, a cohort of patients from our institutional experience was included. Efficacy outcomes were the rate of successful angiography and the rate of surgical adjustment/revision after IOA. Safety outcomes were the rate of angiography-related complications and mortality. Data were analyzed using a random-effects meta-analysis of proportions, and statistical heterogeneity was assessed. RESULTS A total of 26 studies with 142 patients plus 32 subjects from our institution were included in the analysis. The rate of successful intraoperative angiography was 98% (95% CI 94% to 99%; I2=0%). The rate of surgical adjustment/revision was 18% (95% CI 12% to 28%; I2=0%). The rate of complications related to the angiography was 1% (95% CI 0% to 5%; I2=0%). There were no deaths associated with IOA. CONCLUSION We found that IOA performed with patients in prone, three-quarters prone, and park-bench positions is feasible and safe with a non-negligible rate of intraoperative post-angiographical surgical adjustment/revision. Our findings suggest that the performance of IOA to complement vascular neurosurgical procedures might have a valuable role in favoring patient outcomes.
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Affiliation(s)
- Juan Vivanco-Suarez
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Georgios S Sioutas
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Irina-Mihaela Matache
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Physiology, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
| | - Najib Muhammad
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mohamed M Salem
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sandeep Kandregula
- Department of Neurosurgery, LSU Health Shreveport, Shreveport, Louisiana, USA
| | - Brian T Jankowitz
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jan-Karl Burkhardt
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Visish M Srinivasan
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Takamiya S, Yamazaki K, Tokairin K, Osanai T, Shindo T, Seki T, Fujimura M. Intraoperative Identification of the Shunt Point of Spinal Arteriovenous Malformations by a Selective Arterial Injection of Saline to Subtract Signals of Indocyanine Green: Technical Note. World Neurosurg 2021; 151:132-137. [PMID: 34004358 DOI: 10.1016/j.wneu.2021.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND It is crucial to identify a shunt point for spinal arteriovenous malformation (AVM) treatment. For this purpose, some intraoperative supports have been reported-intravenous injection of indocyanine green (ICG), selective arterial injection of ICG, and selective arterial injection of saline with a high frame rate digital camera. However, there are difficulties in accurately identifying the shunt point, especially if the lesion has multiple feeders. The aim of this technical note was to report a novel method, selective arterial injection of saline to subtract signals of ICG, to precisely identify perimedullary arteriovenous fistula shunt points having multiple feeding arteries. METHODS After exposing the lesion, a 4-F catheter was cannulated into the origins of the segmental artery. ICG was injected intravenously as a first step, and then heparinized saline solution was flushed from the catheter. RESULTS Compared with other methods, this method could identify the exact shunt point and was effective for certain shunt point obliterations. CONCLUSIONS Despite having similar invasiveness, selective arterial injection of saline to subtract signals of ICG is superior to previously described techniques, such as selective arterial injection of ICG. Therefore, it will be useful in spinal arteriovenous malformation surgical treatment.
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Affiliation(s)
- Soichiro Takamiya
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan.
| | - Kazuyoshi Yamazaki
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kikutaro Tokairin
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Toshiya Osanai
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Takashi Shindo
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Toshitaka Seki
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Miki Fujimura
- Department of Neurosurgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Sasaki K, Endo H, Niizuma K, Nishijima Y, Osawa S, Fujimura M, Tominaga T. Efficacy of intra-arterial indocyanine green angiography for the microsurgical treatment of dural arteriovenous fistula: A case report. Surg Neurol Int 2020; 11:46. [PMID: 32257572 PMCID: PMC7110105 DOI: 10.25259/sni_588_2019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 02/26/2020] [Indexed: 11/04/2022] Open
Abstract
Background In this study, we report a case of dural arteriovenous fistula (dAVF) that was successfully treated using intra-arterial indocyanine green (IA-ICG) videoangiography during open surgery. Moreover, the findings of IA-ICG videoangiography were compared with those of intraoperative digital subtraction angiography (DSA). Case Description A 72-year-old male patient with a history of hypertension, hyperlipidemia, and thrombocytosis presented with generalized seizure. DSA revealed Cognard Type III dAVF in the superior wall of the left transverse sinus, which was fed by a single artery (the left occipital artery [OA]) and drained into a single vein (the left temporal cortical vein), without drainage into a venous sinus. Since transarterial embolization was considered challenging due to the tortuosity of the left OA, surgical interruption of the shunt was performed by craniotomy. After excising the feeding artery, we were unable to observed dAVF on intraoperative DSA. However, IA-ICG videoangiography revealed the remaining shunt, which was fed by the collateral route from the feeding artery. The shunting point and draining vein were then surgically resected to eliminate the shunt. The shunt was not observed during the second IA-ICG videoangiography conducted after resection. Conclusion ICG videoangiography is a better method compared with DSA in terms of visualizing fine vascular lesions. In contrast to the typical intravenous administration, selective IA-ICG can be repeatedly injected at a minimal dose. IA-ICG is a useful intraoperative tool that can be used to evaluate the elimination of the dAVF.
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Affiliation(s)
- Keisuke Sasaki
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan
| | - Hidenori Endo
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan
| | - Kuniyasu Niizuma
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan.,Department of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Biomedical Engineering, Tohoku University, Japan.,Departments of Neurosurgical Engineering and Translational Neuroscience, Graduate School of Medicine, Tohoku University, Japan
| | - Yasuo Nishijima
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan
| | - Shinichiro Osawa
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan
| | - Miki Fujimura
- Department of Neurosurgery, Kohnan Hospital, Sendai, Japan
| | - Teiji Tominaga
- Departments of Neurosurgery, Graduate School of Medicine, Tohoku University, Japan
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Haynes J, Nossek E, Shapiro M, Chancellor B, Frempong-Boadu A, Peschillo S, Alves H, Tanweer O, Gordon D, Raz E. Radial Arterial Access for Thoracic Intraoperative Spinal Angiography in the Prone Position. World Neurosurg 2020; 137:e358-e365. [PMID: 32032790 DOI: 10.1016/j.wneu.2020.01.208] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 01/26/2020] [Accepted: 01/27/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Verification of complete occlusion or resection of neurovascular lesions is often performed using intraoperative angiography. Surgery for spinal vascular lesions such as arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) is typically performed with the patient in the prone position, making intraoperative angiography difficult. No standardized protocol is available for intraoperative angiography during spinal surgery with the patient in the prone position. We have described our experience using radial artery access for intraoperative angiography in thoracic spinal neurovascular procedures performed with the patient in the prone position. METHODS We reviewed the data from all patients who had undergone surgical resection of spinal vascular lesions in the prone position with radial artery vascular access for intraoperative angiography. The patients were treated in a hybrid endovascular operating room. RESULTS A total of 4 patients were treated in the prone position using transradial artery access intraoperative angiography for confirmation of complete resection of the vascular lesions. Of the 4 patients, 2 had undergone surgery for a dural AVF, 1 for a pial AVF, and 1 for an AVM of the filum terminale. None of the patients had experienced any procedural complications. CONCLUSION Radial artery access for intraoperative angiography during spinal neurovascular procedures in which selective catheterization of a thoracic branch is necessary is feasible, safe, and practical.
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Affiliation(s)
- Joseph Haynes
- University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Erez Nossek
- Department of Neurosurgery, New York University School of Medicine, New York, New York, USA
| | - Maksim Shapiro
- Section of Neurointerventional Radiology, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Bree Chancellor
- Section of Neurointerventional Radiology, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Anthony Frempong-Boadu
- Department of Neurosurgery, New York University School of Medicine, New York, New York, USA
| | - Simone Peschillo
- Department of Neurosurgery, University of Catania, Catania, Italy
| | - Hunter Alves
- Department of Neurosurgery, New York University School of Medicine, New York, New York, USA
| | - Omar Tanweer
- Department of Neurosurgery, New York University School of Medicine, New York, New York, USA
| | - David Gordon
- Department of Neurosurgery, New York University School of Medicine, New York, New York, USA
| | - Eytan Raz
- Section of Neurointerventional Radiology, Department of Radiology, New York University School of Medicine, New York, New York, USA.
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Yu JX, Hong T, Krings T, He C, Ye M, Sun LY, Zhai XD, Xiang SS, Ma YJ, Bian LS, Ren J, Tao PY, Li JW, Yang F, Li GL, Ling F, Zhang HQ. Natural history of spinal cord arteriovenous shunts: an observational study. Brain 2019; 142:2265-2275. [PMID: 31211368 DOI: 10.1093/brain/awz153] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 03/28/2019] [Accepted: 04/15/2019] [Indexed: 11/12/2022] Open
Abstract
Abstract
The natural history of intradural spinal cord arteriovenous shunts is unknown. We performed an observational study in a consecutive patient cohort with symptomatic intradural spinal cord arteriovenous shunts who were admitted to three institutes to investigate the clinical course of this complex disease, which would provide valuable evidence to inform clinical decision-making. The clinical course of patients with symptomatic intradural spinal cord arteriovenous shunts from initial presentation to occurrence of clinical deterioration, initiation of treatment, or last follow-up was analysed. Patients with at least 1 month of observation were included in this study. Clinical onset and deterioration patterns were divided into acute and gradual. Annual and cumulative rates of clinical deterioration as well as their risk factors were analysed using Kaplan-Meier life table analysis and Cox proportional hazards model. To assess risks and benefits of treatment, post-treatment clinical courses were further assessed. Four hundred and sixty-six patients with a mean observational period of 36.9 ± 58.8 months were included; 56.7% of patients presented with acute onset, of whom 77.3% experienced spontaneous recovery. Age of onset older than 28 years, initial modified Aminoff and Logue scale of >3, mid-thoracic lesions and non-ventral lesions were independent predictors of failure for spontaneous recovery. The annual risk of general, acute and gradual clinical deterioration after onset was 30.7%, 9.9% and 17.7%, respectively. Risk of deterioration was highest in the early period after initial onset. Acute onset was the only independent risk factor [hazard ratio 1.957 (95% confidence interval, CI 1.324–2.894); P = 0.0008] of acute deterioration and gradual onset was the strongest predictor [hazard ratio 2.350 (95% CI 1.711–3.229); P < 0.0001] of the gradual deterioration among all the stratifying factors. After invasive treatment, complete obliteration was achieved in 37.9% of patients (138 of 364) and improved or stable clinical status was noted in 80.8% of patients. Forty-two patients (11.5%) experienced permanent complications. Overall post-treatment deterioration rate was 8.4%/year, and 5.3%/year if permanent complications were excluded. The natural history of symptomatic spinal cord arteriovenous shunts is poor, especially in the early period after onset, and early intervention is thus recommended. Initial onset pattern significantly affects the natural history of the lesion, which prompts a differentiated treatment strategy.
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Affiliation(s)
- Jia-Xing Yu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Tao Hong
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Timo Krings
- Division of Neuroradiology, Department of Medical Imaging, Toronto Western Hospital, Toronto, Canada
| | - Chuan He
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Ming Ye
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Li-Yong Sun
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Xiao-Dong Zhai
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Si-Shi Xiang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Yong-Jie Ma
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Li-Song Bian
- Department of Neurosurgery, Beijing Haidian Hospital, Beijing, China
| | - Jian Ren
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Peng-Yu Tao
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Jing-Wei Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Fan Yang
- Department of Neurosurgery, Beijing United Family Hospital, Beijing, China
| | - Gui-Lin Li
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Feng Ling
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
| | - Hong-Qi Zhang
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
- International Neuroscience Institute (China-INI), Beijing, China
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Hamauchi S, Osanai T, Seki T, Kawabori M, Okamoto M, Hida K, Houkin K. Intraoperative real-time identification of abnormal vessels within the bright field by superselective arterial injection of saline and its slow-motion recording using a high frame rate digital camera during surgical treatment of spinal arteriovenous shunts: technical note. J Neurosurg Spine 2018; 29:576-581. [PMID: 30095384 DOI: 10.3171/2018.3.spine1854] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 03/29/2018] [Indexed: 11/06/2022]
Abstract
The authors describe a novel method of observing blood flow in abnormal vessels with slow-motion video during surgical treatment of spinal arteriovenous shunts. The method is based on the use of superselective angiography with saline for visualizing abnormal vessels in bright field and commercially available high frame rate digital camera for recording slow-motion video.
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Affiliation(s)
- Shuji Hamauchi
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
| | - Toshiya Osanai
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
| | - Toshitaka Seki
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
| | - Masahito Kawabori
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
| | - Michinari Okamoto
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
| | - Kazutoshi Hida
- 2Department of Neurosurgery, Sapporo Azabu Neurosurgical Hospital, Sapporo, Hokkaido, Japan
| | - Kiyohiro Houkin
- 1Department of Neurosurgery, Hokkaido University Graduate School of Medicine; and
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