Details of a Researcher - Akiyama, Takenori

Papers - Akiyama, Takenori

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A questionnaire-based survey to evaluate and improve the current HHT medical and social condition in Japan

Arai N, Akiyama T

Surgical Neurology International (Surgical Neurology International) 11 323 - 323 2020

Joint Work, Last author, ISSN 2229-5097

Background: Hereditary hemorrhagic telangiectasia (HHT) is a genetic systemic vascular disease affecting multiple organs and shows recurrent intractable symptoms. This disease has not been widely recognized in Japan until recently. Both diagnosed HHT patients and potential ones have faced difficulties because of the unfamiliarity with the disease in Japan. To evaluate the effect and degree of such a Japanese situation, a questionnaire-based survey was executed in this study. Methods: This survey was carried out among the members of HHT Japan Association. The organization consisted of 102 members (as of 6/2019), mainly HHT patients and their family members. A questionnaire was used to gather demographic data, the effort to reach the diagnosis, and information regarding current patients' and their families' medical managements. Results: Of the 102 questionnaires distributed, we have got 56 responses. The participants were mostly female (30) with an average age of 55.4 ± 14.8 (mean ± standard deviation [SD]) years. The average age of males was 53.5 ± 16.4. Relatively many HHT patients were born in huge cities such as Tokyo, Osaka, and Fukuoka Prefecture (n = 4 to 8 patients). The duration between the initial symptoms and the definite diagnosis was 8.8 ± 10.9 years. The number of hospitals involved in the final diagnosis was 2.38 ± 1.83. More than 70% of patients now have to visit at least two departments and 24% of HHT patients did not want their family to screen for HHT. Conclusion: HHT medical practice in Japan should be further modified, for example, by establishing HHT centers and educating primary care physicians and HHT patients.

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The Anterior Condylar Arteriovenous Fistula from the Viewpoint of the Osseous Venous Anatomy

MIZUTANI Katsuhiro, AKIYAMA Takenori, YOSHIDA Kazunari

No Kekkannai Chiryo (The Japanese Society for Neuroendovascular Therapy) 5 ( 1 ) 56 - 64 2020

ISSN 2423-9119

The anterior condylar arteriovenous fistula (AC-AVF) is a relatively rare AVF that affects the vasculatures adjacent to the hypoglossal canal. We aimed to discuss the etiology and definition of the AC-AVF from the viewpoint of the osseous venous anatomy. Our recent study, which used modern imaging technology (CT digital subtraction venography and cone beam CT reconstructed from 3D rotational angiography), elucidated the intraosseous venous anatomy in this region and the precise fistulous locations of AC-AVFs. Those findings suggest that the AC-AVF is a group of "osseous" AVF that involves the anterior condylar vein and jugular tubercle venous complex (JTVC), and the osseous veins connected to them. The AC-AVF develops in osseous veins adjacent to the hypoglossal canal, and it is one of the most common subtypes of osseous AVFs. The angioarchitectures and etiology of AC-AVFs discussed herein are essential to understand this clinical entity.

Targeted embolisation for coexisting conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas with a varix on a shared drainer†

Yoshida K, Niimi Y, Kamamoto D, Fukumura M, Imai R, Nagoshi N, Akiyama T

British Journal of Neurosurgery (British Journal of Neurosurgery) 37 ( 5 ) 1 - 6 2020

Research paper (scientific journal), Joint Work, Last author, Corresponding author, ISSN 02688697

Background: The coexistence of vascular malformations in the conus medullaris and cauda equina has been rarely reported, and the complex angioarchitecture in multiple arteriovenous lesions remains poorly understood. Case description: A 17-year-old woman presented with a sudden-onset, stepwise worsening of weakness and pain in the bilateral legs. Angiography revealed conus medullaris arteriovenous malformation and cauda equina arteriovenous fistulas. One of the drainers was shared between the coexisting lesions and harboured a varix. Targeted embolisation of a fistulous point in the conus lesion was performed with precaution to prevent occluding the common drainage route, which led to symptom improvement with angiographical diminishment of the varix. Conclusions: Recognising that communications between drainers can be observed in multiple spinal arteriovenous lesions is important in facilitating a safe embolisation. Cautious assessment of angiogram with fusion images of cone-beam computed tomography and volumetric T2 magnetic resonance imaging can help in establishing the diagnosis and treatment strategy.

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Analysis of Temporobasal Vein with Short Subdural Segment for Anterior Transpetrosal Approach

Tamura R, Toda M, Morimoto Y, Sato M, Akiyama T, Yoshida K

World Neurosurgery (World Neurosurgery) 132 e554 - e562 2019.12

Joint Work, ISSN 18788750

© 2019 Elsevier Inc. Background: The anterior transpetrosal approach (ATPA) is applied to petroclival and brainstem lesions. Although neurosurgeons need to minimize the risk of neurologic complications, brain retraction is necessary for procedures of ATPA. Bridging veins (BVs) limit mobility of the temporal lobe. In the present study, BVs around the petrous bone were analyzed, focusing on the dural entrance and termination points. Methods: The relationship between subdural and meningeal segments of temporobasal veins (TBVs) was analyzed by preoperative computed tomography venography in 102 patients who underwent ATPA. TBVs were classified by the dural entrance and termination points. Results: TBVs mainly entered the transverse sinus and rarely entered transverse-sigmoid sinus (T-S) junction and superior petrosal sinus (SPS). TBVs entered a dural sinus either directly or indirectly through a meningeal vein. The changes in vascular diameter of the lumen, shape, and course were identified between the subdural and meningeal segments. Generally, BVs with long subdural segment do not limit mobility of the temporal lobe. TBVs draining into the T-S junction and SPS tended to be shorter than those draining into the transverse sinus. Furthermore, a few TBVs indirectly entered the dural sinuses through the meningeal vein (early dural entrance). The subdural segment of these TBVs was much shorter. Conclusions: TBVs entering the T-S junction or SPS with short subdural segment may limit the mobility of the temporal lobe. Changes in vascular diameter, shape, and course were detected by computed tomography venography, which was helpful to detect the subdural-meningeal transition.

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A Novel Flow Dynamics Study of the Intracranial Veins Using Whole Brain Four-Dimensional Computed Tomography Angiography.

Katsuhiro Mizutani, Nobuhiko Arai, Masahiro Toda, Takenori Akiyama, Hirokazu Fujiwara, Masahiro Jinzaki, Kazunari Yoshida

World neurosurgery (World Neurosurgery) 131 e176 - e185 2019.11

Joint Work, ISSN 18788750

BACKGROUND: The flow dynamics of the intracranial venous channels are fundamentally important for understanding intracranial physiology and pathophysiology. However, the method clinically applicable to the evaluation of the flow dynamics of the intracranial venous system has not been well described in the reported data. We have developed a new method to evaluate intracranial venous flow direction and velocity using 4-dimensional (4D) computed tomography angiography (CTA). The aim of the present study was to verify the accuracy and validity of 4D-CTA in a clinical setting. METHODS: We retrospectively analyzed 97 veins from 26 patients (16 cases of arteriovenous shunt disease, 9 intracranial tumor cases, and 1 cerebral aneurysm case) who had undergone both 4D-CTA and conventional digital subtraction angiography (DSA). Using 4D-CTA, we analyzed the time-density curve with gamma distribution extrapolation and obtained the direction of the flow and flow velocity of each vein. The direction of the flow in 4D-CTA was also collated with that obtained using conventional DSA to verify the experimental method. RESULTS: The direction of the flow determined by 4D-CTA was consistent with that of conventional DSA in 94.8% of cases. The average venous flow velocity was 64.3 mm/second and 81.8 mm/second, respectively, in the antegrade and retrograde channels affected by arteriovenous shunts. CONCLUSIONS: The present flow analysis using 4D-CTA enabled us to evaluate the direction and velocity of intracranial venous flow. Other than some limitations, the presented method is reliable and its potential for application in clinical settings is promising.

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A Case of Aggressive Recurrent Intracranial Subdural Hematoma Associated with Angiosarcoma Originating from the Skull

Kanazawa T, Miwa T, Akiyama T, Ohara K, Kosugi K, Nishimoto M, Yoshida K

World Neurosurgery (World Neurosurgery) 126 120 - 123 2019.06

Joint Work, ISSN 18788750

© 2019 Elsevier Inc. Background: Angiosarcoma often arises as a cutaneous disease in the scalp and the face; however, subdural hematoma (SDH) associated with angiosarcoma is extremely rare. Case Description: A 72-year-old woman visited our hospital with gait disorder and progressive consciousness disturbance approximately 3 months after a minor head injury. Initially, on reviewing the results of imaging studies, she was diagnosed with traumatic chronic SDH. Despite repeated operations thereafter, including the embolization of the middle meningeal artery, her general condition progressively worsened, and computed tomography of head repeatedly showed the recurrence of SDH. Based on histopathologic and intraoperative findings, she was finally diagnosed with angiosarcoma originating from the skull. She died shortly thereafter because of aggressive recurrent intracranial SDH caused by leptomeningeal dissemination. Conclusions: In addition to cancers metastatic to the skull or dura mater, angiosarcoma should be included in the differential diagnosis for patients with repeated SDH and bone defect. An effective treatment for angiosarcoma with SDH that shows an unfavorable prognosis has not been established; however, an early diagnosis might be useful for a novel treatment.

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Hemodynamic stress distribution identified by SPECT reflects ischemic symptoms of Moyamoya disease patients.

Nobuhiko Arai, Takashi Horiguchi, Satoshi Takahashi, Tadaki Nakahara, Takenori Akiyama, Masahiro Jinzaki, Kazunari Yoshida

Neurosurgical review (Neurosurgical Review) 43 ( 5 ) 1323 - 1329 2019

Joint Work, ISSN 03445607

This study aimed to validate the hypothesis that the ratio of cerebral blood flow (CBF) at rest in the lenticular nucleus (LN) territory to that in the middle cerebral artery (MCA) territory is higher in symptomatic Moyamoya disease (MMD) patients than in asymptomatic MMD patients. This was a retrospective observational study of adult patients with documented MMD who underwent single-photon emission computed tomography (SPECT) and had been examined at the Department of Neurosurgery of Keio University Hospital during a 10-year period (2006-2016). The diagnosis was made on the basis of typical imaging findings. We classified unoperated MMD patients into three groups: class I, no evidence of stenosis or occlusion hemispheres and without symptoms in unilateral MMD patients; class II, hemispheres with stenosis or occlusion but without ischemic symptoms; and class III, hemispheres with evidence of stenosis or occlusion associated with ischemic symptoms. Hemodynamic stress distribution (hdSD) was defined as the ratio of CBF in one LN to the CBF in the peripheral MCA; this was obtained by SPECT at rest. We compared the values of CBF and hdSD among the groups. A total of 173 adult patients were diagnosed with MMD from January 1, 2006, to January 1, 2016. Among them, 85 MMD patients underwent SPECT studies. After excluding inappropriate cases, 144 hemispheres were included in our analysis. hdSD was significantly higher (p < 0.001) in hemispheres with ischemic symptoms (class III, mean hdSD = 1.1; 36 sides) than in those without symptoms (class II, mean hdSD = 1.03; 82 sides). However, CBF at rest in the MCA or LN was not significantly associated with ischemic symptoms. The optimal threshold for hdSD to have ischemic symptoms was 1.040 (area under the curve; 74% sensitivity 91.7% and specificity 54.9%). We used SPECT to investigate cerebral blood from MMD patients and found that high hdSD values were predictive of ischemic symptom development in these patients.

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The Anterior Condylar Arteriovenous Fistula from the Viewpoint of the Osseous Venous Anatomy

Mizutani Katsuhiro, Akiyama Takenori, Yoshida Kazunari

脳神経血管内治療 (特定非営利活動法人日本脳神経血管内治療学会) 13 ( 3 ) 97 - 104 2019

ISSN 1882-4072

Traumatic Anterior Ethmoidal Artery Pseudoaneurysm with Repeated Epistaxis Treated by Transarterial Embolization: A Case Report

Kuranari Yuki, Akiyama Takenori, Yanagisawa Kaoru, Kamamoto Dai, Mizutani Katsuhiro, Takahashi Satoshi, Saito Shin, Ozawa Hiroyuki, Ogawa Kaoru, Yoshida Kazunari

脳神経血管内治療 (特定非営利活動法人日本脳神経血管内治療学会) 13 ( 2 ) 72 - 76 2019

Joint Work, ISSN 1882-4072

Objective: Pseudoaneurysms of the internal carotid artery (ICA) and sphenopalatine artery (SPA) are recognized as sources of arterial epistaxis following head and face trauma. However, epistaxis involving pseudoaneurysm of the anterior ethmoidal artery (AEA) is extremely rare.Case Presentation: A 25-year-old man experienced massive epistaxis due to a ruptured traumatic pseudoaneurysm of the AEA. The patient had suffered head and face trauma in a car accident. CT showed fractures of the frontal, ethmoidal, and maxillary bones, and he was managed conservatively. Nine days after the injury, he had sudden, massive epistaxis. Angiography showed a right AEA aneurysm, which was treated successfully with transarterial embolization using n-butyl-2-cyanoacrylate (NBCA).Conclusion: Although pseudoaneurysm of the AEA is a rare cause of epistaxis, it is important to consider this diagnosis, in addition to pseudoaneurysm of the SPA and ICA, when a patient has massive arterial epistaxis following a traumatic skull base fracture, especially if the fracture is adjacent to the ethmoid sinus. Transarterial embolization using glue is a feasible therapeutic option for this condition.

Skull Base Venous Anatomy Associated with Endoscopic Skull Base Neurosurgery: A Literature Review

Mizutani K, Akiyama T, Yoshida K, Toda M

World Neurosurgery (World Neurosurgery) 120 405 - 414 2018.12

Joint Work, ISSN 18788750

© 2018 Elsevier Inc. An understanding of the anatomy and function of the skull base venous channels is fundamentally important for safe performance of endoscopic surgery for skull base lesions. This review focuses on 4 skull base venous channels—namely, the intercavernous sinuses, basilar plexus, osseous veins, and inferior petroclival vein—because these have been less recognized by neurosurgeons than other major venous channels such as the inferior petrosal sinus. We reviewed the literature concerning these 4 venous channels and discussed their anatomy and function. The literature review was mainly based on an electronic search in PubMed using the following terms: “intercavernous sinus,” “basilar plexus,” “emissary veins,” “diploic vein,” “basilar plexus,” “intraosseous vein,” “inferior petroclival/petro-occipital vein,” and “transclival.” A total of 50 articles were included in this review. Detailed anatomic features of the 4 structures have been elucidated in the literature. All of these venous channels run along the skull base and have multiple connections with surrounding venous structures. Because of their location, they occasionally obstruct the surgical view and are sometimes implicated in intraoperative hemorrhage, air embolism during endoscopic skull base surgery, and postoperative hematoma. They usually function as a venous reservoir of cranial venous drainage; however, they are less often directly involved in normal brain perfusion. Knowledge about the functional and morphologic anatomy of the skull base venous channels is important for neurosurgeons to avoid unexpected complications during endoscopic skull base surgery.

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An analysis of the anatomic route of the hypoglossal nerve within the hypoglossal canal using dynamic computed tomography angiography in patients with anterior condylar arteriovenous fistulas

Oishi Y, Akiyama T, Mizutani K, Horiguchi T, Imanishi N, Yoshida K

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 174 207 - 213 2018.11

Joint Work, ISSN 03038467

© 2018 Elsevier B.V. Objective: The venous outlet of anterior condylar arteriovenous fistulas (AC-AVFs) often empties into the anterior condylar vein (ACV). Hypoglossal nerve palsy is one of the major complications after transvenous embolization (TVE) for the AC-AVF within the hypoglossal canal. However, no studies have investigated the route of the hypoglossal nerve within the hypoglossal canal in AC-AVF. The aim of the current study is to retrospectively verify the anatomical route of the hypoglossal nerve within its canal using dynamic computed tomography angiography (CTA) in order to facilitate the safe TVE for AC-AVF. Patients and methods: We included five patients with AC-AVF from 2011 to 2017. Dynamic CTA was performed on all patients. When the ACV was well-visualized by dynamic CTA, the hypoglossal nerve could be recognized as a less-intense structure within the surrounding enhanced vasculatures and the nerve route within the canal was analyzed. We also analyzed the location of the fistulas by digital subtraction angiography and cone-beam computed tomography. Results: In all five patients, the filling defect of the hypoglossal nerve ran through the most caudal portion of the hypoglossal canal. The fistulous pouches were located in the hypoglossal canal in three cases, and in the jugular tubercle venous complex in two cases. In all three cases with AC-AVF in the hypoglossal canal, the fistulous pouches were located in the superior wall of the hypoglossal canal, which means superior to the ACV. We performed TVE in four patients and none developed post-therapeutic hypoglossal nerve palsy. Conclusion: In the current study, dynamic CTA is useful for detecting the hypoglossal nerve within the hypoglossal canal. The hypoglossal nerve usually ran the bottom of its canal and the fistulous pouches were usually located at the superior aspect of the canal opposite side to the hypoglossal nerve. Accordingly, the selective embolization within the fistulous pouch located in the superior aspect of the ACV including jugular tubercle venous complex can reduce the risk of hypoglossal nerve palsy.

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Pros and cons of using ORBEYE™ for microneurosurgery

Takahashi S, Toda M, Nishimoto M, Ishihara E, Miwa T, Akiyama T, Horiguchi T, Sasaki H, Yoshida K

Clinical Neurology and Neurosurgery (Clinical Neurology and Neurosurgery) 174 57 - 62 2018.11

Joint Work, ISSN 03038467

© 2018 Elsevier B.V. Objective: To evaluate the pros and cons of using a newly developed microscope, ORBEYE™, during microneurosurgery. Patients and methods: ORBEYE™ use in 14 microneurosurgical procedures was retrospectively assessed by nine neurosurgeons after the procedure. A questionnaire comprising 20 questions was designed and used for evaluation. Results: Compared with the current gold standard, the binocular microscope, ease of setting up the equipment was scored the highest, whereas ease of conducting surgery in a position of an assistant was scored the lowest. Among characteristics of ORBEYE™ itself, the space-saving feature was scored the highest and was followed by the ability to perform procedures in a comfortable position. The only characteristic that was rated below average was ease of operation in a position of an assistant. Neurosurgeons with greater experience (more than five procedures using ORBEYE™) provided significantly higher scores (p = 0.0196) for characteristics of ORBEYE™ itself compared with neurosurgeon with fewer ORBEYE™ experience. Conclusions: The main benefits of the ORBEYETM are its compact size and freedom from focusing through the eye lens of a conventional binocular microscope. However, it appears to be disadvantageous for operating in a position of an assistant because the surgical field has a rotated view on the monitor from a position of an assistant. Nonetheless, because of certain advantages, we believe the ORBEYE™ could be of additional help to use of conventional binocular microscope at the moment and will facilitate microneurosurgery in the future.

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Combined Endoscopic Endonasal and Video-microscopic Transcranial Approach with Preoperative Embolization for a Posterior Pituitary Tumor

Yoshida K, Toda M, Akiyama T, Takahashi S, Nishimoto M, Ozawa H, Ikari Y, Yoshida K

World Neurosurgery (World Neurosurgery) 119 201 - 208 2018.11

Joint Work, ISSN 18788750

© 2018 Elsevier Inc. Background: Posterior pituitary tumor is rare, and its optimal surgical strategy is undetermined. Surgical removal of posterior pituitary tumors is often complicated by their hypervascularity. Prevention and preparation for excessive hemorrhage is crucial for safe resection. Case Description: A 69-year-old woman presented with bitemporal hemianopsia and was found to have a sellar tumor with suprasellar extension, resembling a pituitary adenoma. Microscopic transsphenoidal resection was attempted but was interrupted by a massive intraoperative hemorrhage. Pathologic diagnosis was a spindle cell oncocytoma, and she was referred to our institution. She underwent preoperative embolization to decrease tumor vascularity, and resection was performed using a combined endoscopic endonasal and video-microscopic transcranial approach, using a 4K three-dimensional (3D) video microscope. The final diagnosis was a posterior pituitary tumor with immunopositivity for thyroid transcription factor-1, with preferred interpretation as a pituicytoma. Conclusions: A combined endonasal and transcranial approach with preoperative embolization is a useful strategy for hypervascular posterior pituitary tumors. A 4K 3D video microscope is compact, and it provides high-resolution images, contributing larger surgical space and facilitating a multi-team surgery.

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Primary Intracranial Rhabdomyosarcoma in the Cerebellopontine Angle Resected After Preoperative Embolization

Keisuke Yoshida, Tomoru Miwa, Takenori Akiyama, Masaaki Nishimoto, Dai Kamamoto, Kazunari Yoshida

World Neurosurgery (Elsevier Inc.) 116 110 - 115 2018.08

Research paper (scientific journal), Joint Work, ISSN 18788750

Background: Primary intracranial rhabdomyosarcoma is a very rare malignant tumor. Owing to moderately vascular and firm characteristics of the tumor, complete removal without complications is often difficult. In pediatric patients, the volume of total blood is less than in adults, and minimal intraoperative hemorrhage is desirable. Case Description: A 6-year-old boy presented with ataxia and was found to have a large cerebellopontine angle tumor and hydrocephalus. The patient underwent preoperative coil embolization of the anterior inferior cerebellar artery to decrease tumor vascularity, and gross total removal was achieved on the same day via a suboccipital approach. Pathologic diagnosis was rhabdomyosarcoma. Conclusions: Successfully resection of primary intracranial rhabdomyosarcoma was achieved after preoperative embolization. Tumor vascularity was significantly reduced, and gross total removal was achieved safely with less hemorrhage.

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Preoperative Assessment of Pathologic Subtypes of Meningioma and Solitary Fibrous Tumor/Hemangiopericytoma Using Dynamic Computed Tomography: A Clinical Research Study.

Nobuhiko Arai, Katsuhiro Mizutani, Satoshi Takahashi, Yukina Morimoto, Takenori Akiyama, Takashi Horiguchi, Hatano Mami, Kazunari Yoshida

World neurosurgery (World Neurosurgery) 115 e676 - e680 2018.07

Joint Work, ISSN 18788750

BACKGROUND: Solitary fibrous tumors (SFTs)/hemangiopericytomas (HPCs) are highly vascularized tumors well known for malignant, invasive, and highly vascular features. To date, several studies have reported the preoperative imaging findings of SFTs/HPCs. In this study, computed tomography (CT) tumor values acquired from dynamic CT scan were selected to determine the tumor pathology of highly vascular tumors, such as SFTs/HPCs. METHODS: We conducted a retrospective study on patients with pathologically diagnosed meningiomas and SFTs/HPCs who had undergone a dynamic contrast CT scan. We assessed and compared the CT values of these tumors according to the pathology. RESULTS: From a total of 34 patients, 30 patients with meningiomas and 4 patients with HPCs were included. The mean CT values of SFTs/HPCs and angiomatous meningioma were statistically significantly higher than those of the other meningioma subtypes (P = 0.003). We also performed receiver operating characteristic curve analyses to detect an appropriate cutoff point for the CT value to differentiate tumor pathology, and the calculated threshold was 161 Hounsfield units (HU) (sensitivity, 100%; specificity, 75%; area under the curve, 0.87; 95%, CI 0.75-0.99). CONCLUSIONS: This study showed that obtaining a CT value is useful in determining highly vascular tumor pathology preoperatively. When considering neurosurgical extra-axial tumor removal, and when the CT value of tumors is >161 HU, then highly vascular tumors such as SFTs/HPCs or angiomatous meningiomas are likely, and this should be considered prior to surgical intervention and for risk assessment.

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Intraosseous venous structures adjacent to the jugular tubercle associated with an anterior condylar dural arteriovenous fistula

Katsuhiro Mizutani, Takenori Akiyama, Yasuhiro Minami, Masahiro Toda, Hirokazu Fujiwara, Masahiro Jinzaki, Kazunari Yoshida

Neuroradiology (Springer Verlag) 60 ( 5 ) 487 - 496 2018.05

Research paper (scientific journal), Joint Work, ISSN 00283940

Purpose: Although involvement of the osseous component with an anterior condylar dural arteriovenous fistula (AC-DAVF) has been frequently described, osseous venous structures in which AC-DAVFs develop have not been fully elucidated. We investigated osseous venous structures adjacent to the hypoglossal canal in normal controls and patients with AC-DAVFs. Methods: The study included 50 individuals with unruptured aneurysms as normal controls and seven patients with AC-DAVFs. Osseous venous structures adjacent to the hypoglossal canal in normal controls were analyzed using computed tomography (CT) digital subtraction venography. In patients with AC-DAVFs, the fistulous pouches, draining veins, and surrounding venous structures were examined using cone beam CT. Results: In 46.0% of laterals in normal controls, osseous venous structures were visualized within the jugular tubercle superomedially to the hypoglossal canal. We named these structures the jugular tubercle venous complex (JTVC). The JTVC was always continuous with the anterior condylar vein and was sometimes connected to surrounding venous channels. We detected nine fistulous pouches in the seven patients with AC-DAVFs. The fistulous pouches were in the JTVC (33.3%), anterior condylar vein (33.3%), and other venous channels within the exoccipital region (33.3%). Conclusion: Although the JTVC is a venous structure frequently found in normal people, it had not been investigated until now. The venous channel between the anterior condylar vein and JTVC is a common origin site for AC-DAVFs, and it was associated with 66.6% of the AC-DAVF cases in the current study.

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The analysis of the cerebral venous blood volume in cavernous sinus using 320 row multi-detector CT

Katsuhiro Mizutani, Masahiro Toda, Yumi Yajima, Takenori Akiyama, Hirokazu Fujiwara, Kazunari Yoshida, Masahiro Jinzaki

Clinical Neurology and Neurosurgery (Elsevier B.V.) 167 11 - 16 2018.04

Research paper (scientific journal), Joint Work, ISSN 03038467

Objectives: : Functional venous anatomy in the brain has been mostly understood from the morphological and embryological points of view and no published study has directly evaluated the blood flow volume of cerebral small veins. We developed a method to directly evaluate the relative blood volume in small venous channels using multi-detector computed tomography (CT) and applied it to evaluate the blood volume in each tributary of the cavernous sinus, which plays an important role in cerebral venous drainage. Patients and Methods: : Ten patients with small brain tumors who had normal venous anatomy were included in the present study. All of them underwent preoperative 320-row multi-detector CT. After injecting the contrast bolus, we measured the Hounsfield units (HUs) at 10 time point over 60 s in each tributary of the cavernous sinus. The gamma distribution fitting to each HU enabled us to obtain a time-density curve and determine the relative venous volume in each venous channel. Results: : In terms of blood volume, the superficial middle cerebral vein and inferior petrosal sinus were the largest inflow and outflow channels of the cavernous sinus and accounted for 36.1% and 24.7% of its inflow and outflow on average, respectively. The superior orbital vein did not contribute to the blood volume passing through the cavernous sinus in the current study. Conclusions: : The present study allowed us to determine the relative blood volume in each tributary of the cavernous sinus, which was very useful to understand the physiological actual venous drainage pattern concerning the cavernous sinus in normal anatomy.

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Fate of the three embryonic dural sinuses in infants: the primitive tentorial sinus, occipital sinus, and falcine sinus

Katsuhiro Mizutani, Tomoru Miwa, Takenori Akiyama, Yoshiaki Sakamoto, Hirokazu Fujiwara, Kazunari Yoshida

Neuroradiology (Springer Verlag) 60 ( 3 ) 325 - 333 2018.03

Research paper (scientific journal), Joint Work, ISSN 00283940

Purpose: The primitive tentorial, occipital, and falcine sinuses are thought to attain the adult pattern or regress between the fetal stage and adulthood. The anatomy of these three primitive dural sinuses has seldom been studied in the infant population, and it remains unclear when these dural sinuses reach the adult condition. Using computed tomography digital subtraction venography (CT-DSV), we analyzed the anatomy of these embryonic dural sinuses in infants. Methods: We included 13 infants who underwent CT-DSV prior to neurosurgery and 35 cases with unruptured cerebral aneurysms as normal adult controls. Three embryonic dural sinuses, i.e., the primitive tentorial, occipital, and falcine sinuses, were retrospectively analyzed in CT-DSV images of infants and adults. We also analyzed the drainage patterns of the superficial middle cerebral vein (SMCV), determined by the connection between the primitive tentorial sinus and the cavernous sinus. Results: The primitive tentorial, occipital, and falcine sinuses were present in 15.4%, 46.2%, and none of the infants, respectively, and in 10.0, 8.6, and 2.9% of the adults, respectively. The difference in SMCV draining pattern between infants and adults was insignificant. The incidence of the occipital sinus was significantly higher in infants than in adults. Conclusions: The connection between the primitive tentorial sinus and the cavernous sinus appears to be established before birth. The occipital sinus is formed at the embryonic stage and mostly regresses after infancy. The falcine sinus is usually obliterated prenatally. Our findings form the basis for interventions by pediatric interventional neuroradiologists and neurosurgeons.

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Advantages of Staged Angioplasty in a Patient with Internal Carotid Artery Pseudo-Occlusion Besides Prevention of Cerebral Hyperperfusion Syndrome

Satoshi Takahashi, Takenori Akiyama, Jin Nakahara, Takahito Yoshizaki, Norihiro Suzuki, Kazunari Yoshida

World Neurosurgery (Elsevier Inc.) 109 409 - 412 2018.01

Research paper (scientific journal), Joint Work, ISSN 18788750

Background Staged angioplasty for carotid artery stenosis has been reported to be effective in preventing postoperative cerebral hyperperfusion syndrome (CHS) in patients with severe carotid stenosis
thus, it is also recommended for patients with internal carotid artery (ICA) pseudo-occlusion, the treatment strategy for which is controversial. Case Description This study reports the case of an Asian man in his 50s who had motor aphasia and right-side weakness caused by pseudo-occlusion of the left ICA. After medical treatment, he underwent a staged angioplasty. After the first stage of percutaneous transluminal angioplasty, anterograde blood flow to the left ICA increased but the distal ICA remained partially collapsed. Initially, the second stage of carotid artery stenting (CAS) was planned for 2 weeks after the first stage
however, hemorrhagic infarction was observed the day before the CAS, and it was postponed by 2 weeks, after adjustment of antiplatelet therapy. At the time of the CAS, the diameter of the initially collapsed left distal ICA was remodeled and it was fully dilated
thus, we used a balloon-type embolic protection device and conducted CAS successfully without apparent embolic complications. The postoperative course was uneventful. The patient did not develop CHS. Conclusions Besides preventing CHS, staged angioplasty has advantages when used for treating patients with ICA pseudo-occlusions in that the extent of dilation of the distal ICA after percutaneous transluminal angioplasty can be confirmed and the development of a possible hemorrhagic infarction can be assessed before stent placement.

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Changes in Utility and Limits of Combined Microsurgical and Endovascular Treatment for Complex Cerebrovascular Disease before and after the Introduction of the Hybrid Operating Room

HORIGUCHI Takashi, AKIYAMA Takenori, TAKAHASHI Satoshi, OHIRA Takayuki, YOSHIDA Kazunari

Surgery for Cerebral Stroke (The Japanese Society on Surgery for Cerebral Stroke) 46 ( 6 ) 453 - 461 2018

ISSN 0914-5508

Here we investigated the changes in utility and limits of combined microsurgical and endovascular treatment for complex cerebrovascular disease before and after the introduction of the hybrid operating room (HOR) in our department. Since 2006, a total of 17 patients (cerebral aneurysm in 12, cerebral arteriovenous malformation in 5) underwent integrated microsurgery with endovascular treatment. In 3 of 11 patients treated before the introduction of HOR, certain problems such as time consumption during patient transfer, disconnected workflow, and complicated operation due to poor quality of support equipment occurred. In contrast, all 6 operations in the HOR were uncomplicated. All therapeutic steps including anesthesia management were planned in a single session. In conclusion, HOR provides a safe and smooth workflow in combined microsurgical and endovascular treatment for complex cerebrovascular diseases.

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