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Background: Some reports have described intraosseous arteriovenous fistulas showing osteolytic changes, but an osseous arteriovenous fistula (AVF) at the jugular bulb showing extensive bone destruction is a very rare disease. Case description: A 60-year-old man presented with pulsatile tinnitus and right facial nerve palsy. Radiological imaging showed a large homogenously enhanced osteolytic lesion at the right jugular foramen. A cerebral angiogram showed a high-flow vascular lesion of the jugular bulb associated with retrograde sinus reflux, resulting in venous congestion of the deep venous system. These findings led us to misdiagnose this lesion as a glomus jugular tumor. However, combined arterial and venous angiography after transarterial embolization revealed the precise angioarchitecture, and we finally diagnosed this lesion as a high-flow osseous AVF at the jugular bulb. We performed transvenous embolization using a triple catheter technique. The lesion was successfully obliterated, and the 6-months angiogram showed no recurrence. Conclusion: A rare case of high flow osseous AVF at the jugular bulb associated with osteolytic changes in the surrounding bony structure is reported. Although many hypervascular lesions at the jugular bulb are glomus tumors, bone destructive osseous AVF at the jugular bulb should be considered.

Purpose To investigate the oncological outcomes of orbital malignant tumors invading the skull base. Methods A retrospective analysis was conducted on 16 patients with orbital malignant tumors invading the skull base. Eleven patients were treated with skull base surgery, four patients were treated with particle therapies, and one patient was treated with chemoradiotherapy (CRT) as initial treatment. Results The most frequent histological type was adenoid cystic carcinoma in seven patients, followed by squamous cell carcinoma in two patients. Local recurrence occurred in two of the six surgically treated patients who did not receive postoperative radiotherapy (RT) or CRT. One of them was successfully salvaged by RT, and the other died of disease. With a median follow‐up of 24 months, the 2‐year overall, local control, and disease‐free survival rates of all patients were 82.5%, 87.5%, and 59%, respectively. Conclusions Patients with positive surgical margins were at risk of local recurrence. Postoperative RT should be considered for all surgically treated patients. Level of Evidence: 4.

Intracranial vessel dissection is a procedural complication associated with endovascular treatment. However, there have been few reports on its potential causes and management during mechanical thrombectomy. In approximately 250 cases of mechanical thrombectomy over the past 5 years at our institution, iatrogenic intracranial dissection occurred in 2 patients (0.8%). In this report, we described these 2 cases that were rescued through emergent stenting. Mechanical thrombectomy, using both a stent retriever and an aspiration catheter, was performed for acute middle cerebral artery M2 occlusion in Patient 1 (a 69-year-old man) and for distal M1 occlusion in Patient 2 (an 83-year-old woman). In both cases, recanalization was achieved with the procedure, but irregular stenosis developed at the initially nonoccluded, but mildly arteriosclerotic, M1, after recanalization. During the thrombectomy procedure, the aspiration catheter sifted up to the arteriosclerotic M1. In both cases, the lesions were considered vessel dissection, due to a shift of the aspiration catheter tip into the arteriosclerotic vessel wall. Repeated percutaneous angiography with antithrombotic therapy failed to improve the lesions and to maintain the antegrade blood flow. Finally, lesions in each patient were successfully rescued through the use of emergent stenting. A drug-eluting stent for coronary use was deployed in Patient 1, and an Enterprise stent was applied in Patient 2. Inadvertent shift of the aspiration catheter into arteriosclerotic vessels can cause a serious intracranial vessel dissection. When performing mechanical thrombectomy, intracranial stents need to be available as rescue treatment devices to manage refractory iatrogenic intracranial vessel dissection.

Although transvenous embolization (TVE) via the superior ophthalmic vein (SOV) is adopted in treating cavernous sinus dural arteriovenous fistula (CS DAVF), its effect on the coil volume is rarely understood. The purpose of the study was to investigate if there is a difference in the total number of coils used and in patient safety when comparing two access strategies. We retrospectively reviewed charts for patients with CS DAVF treated with TVE between January 2008 and March 2018. The baseline patient characteristics, details of procedure, placed coils, and clinical results were compared. A total of 42 patients with CS DAVF were treated with the inferior petrosal sinus (IPS) (n = 32) or SOV (n = 10) approach. TVE via SOV showed a high success rate of 100% (10/10) by transfemoral access. The total number (23 versus 11; P

Background Microvascular decompression (MVD) is the most effective procedure for hemifacial spasm (HFS). MVD results from nonspecialized or low-volume institutes are not always reliable. Most studies on MVD for HFS are retrospective and single centered; to the best of our knowledge, no prospective, multicenter studies exist. Objective To evaluate short- and long-term outcomes and complications in patients who underwent MVD for HFS in specialized Japanese institutions, in this multicenter, prospective, cohort study. Methods Included patients had undergone MVD for HFS in study centers between April 2012 and March 2015. Patients' postoperative grade of involuntary movements and complications were recorded postoperatively at 7 d (short-term) and at 1 (mid-term) and 3 (long-term) yr. Results A total of 486 patients (150 men, 336 women; mean age 53.9 yr with 181 patients over 60 yr) were enrolled during the study period. Neuromonitoring was used in 96.3% of the cases. The complete cure rate of symptom relief, mortality rate, and complication rate at short-term follow-up were 70.6%, 0%, and 15%, respectively. The long-term follow-up was completed by 463 patients (95.3%); the complete cure rate of symptom relief and complication rate were 87.1% and 3.0%, respectively. Conclusion Our study revealed that under expert guidance and intraoperative neuromonitoring, the long-term curative effect rate of MVD for HFS is high, while complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with HFS, including elderly patients.

Intracranial artery occlusion due to a foreign body is a complication associated with cardiac surgery that is treated by various techniques. However, little is known about appropriate strategies for symptomatic intracranial artery stenosis due to an unknown embolic source. We reported a case of middle cerebral artery (MCA) stenosis after mitral valve repair (MVR) for infective endocarditis (IE). An 80-year-old man presented with right hemiplegia. MR angiography findings were normal, and diffusion-weighted imaging revealed subtle ischemic change in the left MCA territory. The patient was diagnosed with cardioembolic stroke owing to IE and performed MVR. Four days later, he suddenly presented with consciousness disorder and left hemiplegia. Computed tomography (CT) confirmed a very low-density area within the right MCA. MR angiography revealed right MCA stenosis, which corresponded to the low-density area on CT images. Diffusion-weighted imaging revealed new ischemic change in the right MCA territory. Angiography confirmed an irregular stenosis at the right M2 with antegrade blood flow, and the hemiplegia resolved during angiography. Conservative therapy was performed; however, the resting 123 I-IMP-single photon emission CT revealed moderate perfusion defect in the right MCA territory, and transient left hemiplegia appeared every few days. Therefore, 19 days after the initial transient ischemic attack, the patient was performed superficial temporal artery–MCA anastomosis, and the patient responded with a good clinical course without recurrence of the ischemic symptoms. This strategy may be a safe and effective treatment for symptomatic intracranial artery stenosis due to an unknown embolic source.

Each year, the Japan Neurosurgical Society (JNS) reports up-to-date statistics from the Japan Neurosurgical Database regarding case volume, patient demographics, and in-hospital outcomes of the overall cohort and neurosurgical subgroup according to the major classifications of main diagnosis. We hereby report patient demographics, in-hospital mortality, length of hospital stay, purpose of admission, number of medical management, direct surgery, endovascular treatment, and radiosurgery of the patients based on the major classifications and/or main diagnosis registered in 2018 and 2019 in the overall cohort (523283 and 571143 patients, respectively) and neurosurgical subgroup (177184 and 191595 patients, respectively). The patient demographics, disease severity, proportion of purpose of admission (e.g., operation, 33.9-33.5%) and emergent admission (68.4-67.8%), and in-hospital mortality (e.g., cerebrovascular diseases, 6.3-6.5%; brain tumor, 3.1-3%; and neurotrauma, 4.3%) in the overall cohort were comparable between 2018 and 2019. In total, 207783 and 225217 neurosurgical procedures were performed in the neurosurgical subgroup in 2018 and 2019, respectively, of which endovascular treatment comprised 19.1% and 20.3%, respectively. Neurosurgical management of chronic subdural hematoma (19.4-18.9%) and cerebral aneurysm (15.4-14.8%) was most common. Notably, the proportion of management of ischemic stroke/transient ischemic attack, including recombinant tissue plasminogen activator infusion and endovascular acute reperfusion therapy, increased from 7.5% in 2018 to 8.8% in 2019. The JNS statistical update represents a critical resource for the lay public, policy makers, media professionals, neurosurgeons, healthcare administrators, researchers, health advocates, and others seeking the best available data on neurosurgical practice.

Background Aneurysms at the origin of a duplicated middle cerebral artery (DMCA) are quite rare. Here, we report a patient with such an aneurysm successfully treated endovascularly using our novel “wrapped-candy” low-profile visualized intraluminal support (LVIS) technique. Case Description A 44-year-old woman underwent endovascular treatment for an unruptured wide-necked aneurysm at the origin of a DMCA that incorporated the origin of the DMCA into its neck. Stent-assisted coiling was performed using our newly developed “wrapped-candy” LVIS technique. To protect the origin of the DMCA and increase the stent metal density at the neck, an LVIS blue 3.5-mm × 22-mm stent was deployed by pushing the delivery wire aggressively to transform the visible wire components of the LVIS into a shape like “wrapped candy,” maximizing the strut compaction at the neck of the aneurysm. Subsequently, the aneurysm component was coiled using a jailed microcatheter. The final procedural angiography demonstrated almost complete aneurysm occlusion with DMCA preservation. Conclusions Stent-assisted coiling can be a feasible treatment for an unruptured, usually wide-necked, aneurysm at the origin of a DMCA. The wrapped-candy LVIS technique may be useful in more challenging morphologies such as wide-necked aneurysms that incorporate the branch origin into the aneurysm neck.

Treating carotid blowout syndrome following rupture of giant pseudoaneurysms is difficult because the destroyed parent artery precludes conventional treatment. We present a patient with a ruptured giant pseudoaneurysm that we occluded using a modified internal trapping technique with low-concentration N-butyl-2-cyanoacrylate (NBCA) and a minimum number of coils. An 80-year-old man with a history of chemoradiation therapy for oropharyngeal cancer presented with several episodes of active bleeding from the subsequent tracheostomy site. Radiological examination revealed a giant right common carotid artery (CCA) pseudoaneurysm. Endovascular internal trapping was performed using both NBCA and coils under proximal flow control. We slowly injected 9 ml of low-concentration NBCA, which subsequently filled the entire pseudoaneurysm. We then injected an additional 2 ml of NBCA into the proximal CCA to achieve complete obliteration. No re-bleeding was observed during the 6-month follow-up. Endovascular internal trapping using low-concentration NBCA was feasible to treat a giant CCA pseudoaneurysm. The injected low-concentration NBCA filled the entire pseudoaneurysm without the risk of catheter entrapment.

Background Mechanical thrombectomy has become the standard treatment for acute ischemic stroke caused by large vessel occlusion; however, refractory occlusions still occur despite various thrombectomy procedures. The double stent retriever (SR) technique, which employs 2 SRs simultaneously at the occlusion, can be useful for such refractory occlusions. Methods We described 2 cases of refractory acute cerebral occlusion despite the use of conventional thrombectomy procedures that were both treated with the double SR technique. To discuss the technical aspects of how this easy-to-perform technique facilitates the device-clot interaction, we also evaluated radiographic findings of the SR strut during the procedure. Results In both cases, conventional thrombectomy procedures, including an SR alone, an aspiration catheter alone, and combined use of the SR and aspiration catheter, failed to recanalize the occlusion. The double SR technique was then performed with the stent-in-stent method in 1 patient and the parallel stent method in 1 patient. One pass of this technique retrieved hard clots and successfully recanalized the refractory occlusion in both cases. Intraprocedural radiographic images of these cases showed that the degree of stent expansion improved after deployment of the second SR compared with the first SR. Conclusions Our radiographic findings suggested that adding a second SR facilitates the device-clot interaction at the occlusion site. The double SR technique may be an easy-to-perform thrombectomy technique to improve clot-capturing ability for the management of refractory acute cerebral artery occlusions.

Although ultrasonographically-guided carotid interventions without contrast medium have been reported in the literature, we found no report regarding stenting of the vertebral artery origin for treatment of stenosis. Here, we report the case of an iodine-allergic patient in whom a stenosis at the origin of the vertebral artery was successfully treated with ultrasonographically-guided stent placement without contrast medium. B-mode longitudinal images were monitored during the insertion of the embolism-protection device, when positioning the stent, and for the evaluation of the stent opening. This technique can be an alternative option in selected patients, especially those allergic to the contrast medium.

The superior ophthalmic vein (SOV) approach through the facial vein is usually preferred for transvenous embolization of a cavernous sinus dural arteriovenous fistula (CS DAVF) when the ipsilateral inferior petrosal sinus is angiographically occluded. However, navigating the microcatheter can sometimes be difficult because of stenosis or tortuous angulation at the junction between the angular vein and SOV. We present a novel transvenous access route to treat a CS DAVF using the ipsilateral deep facial vein through the SOV to reach the cavernous sinus. A 66-year-old woman presented with left-sided chemosis, exophthalmos, and external ophthalmoplegia. Angiography showed a left CS DAVF associated with a dilated SOV and retrograde cortical venous reflux. A dilated drainage vein, which branched from the SOV, ran through the lateral aspect of the orbit and exited the orbit through the inferior orbital fissure. This vein connected with the ipsilateral deep facial vein draining into the facial and internal jugular veins. We performed transvenous embolization via the SOV approach through the deep facial vein and achieved complete obliteration, by placing 3 platinum coils, without complications. Ophthalmic veins may connect with the cavernous sinus and pterygoid plexus, passing through the superior and inferior orbital fissures, respectively. Our case suggests that the deep facial vein may provide access to the SOV through the inferior orbital fissure without passing the difficult tortuous angle between the angular vein and SOV.

Communicating hydrocephalus is a known tumor-related syndrome associated with vestibular schwannoma, which can occur even in small tumor. Radiation has become a popular primary treatment option for small schwannoma; however, little is known about the efficacy and risk accompanying asymptomatic ventriculomegaly on images. We report a case of a 59-year-old woman who suffer from refractory communicating hydrocephalus after radiation for small vestibular schwannoma with asymptomatic ventriculomegaly. After the surgical removal of the tumor, hydrocephalus was gradually improved due to intermittent lumbar puncture and finally resolved without shunt placement. Surgical removal should be considered as the first option for the treatment, even if the patient is asymptomatic and the images revealed a small vestibular schwannoma with only slight ventricular enlargement.

We present a unique sinus protection technique that uses a short-length supercompliant balloon during the transarterial Onyx embolization for the dural arteriovenous fistula (DAVF) of the lateral tentorial sinus. With this technique, we temporarily change the Borden classification from type II to type III, avoiding venous compromise and reducing the risk of Onyx migration into the patent sinus. A 54-year-old man presented with left persistent tinnitus of 4 months’ duration. Cerebral angiography revealed a Borden type II left lateral tentorial sinus-DAVF associated with retrograde cortical venous reflux draining into the vein of Labbé. In the venous phase, the ipsilateral transverse-sigmoid sinus was recognized as a functional sinus and the posterior temporal vein drained into the transverse sinus near the drainage channel. We planned to perform transarterial Onyx embolization using a short-length sinus protection balloon to protect against Onyx migration. During transarterial Onyx injection, a 7 × 7-mm HyperForm balloon was navigated into the affected sinus and positioned to cover the drainage channel from the shunt. After confirming the change in Borden classification with angiography, transarterial Onyx embolization was performed via the middle meningeal artery. This procedure resulted in complete obliteration of the fistula with good patency of both the transverse-sigmoid sinus and neighboring normal cortical veins. No procedure-related complications were observed and the patient remained free of recurrence during the 24-month follow-up period. Short-length balloon-protected Onyx embolization can be safe and effective for the treatment of Borden type II DAVF. Keywords: HyperForm balloon, Lateral tentorial sinus, Onyx, Sinus protection, Tentorial dural arteriovenous fistula

Background The differences between 3-dimensional (3D) high definition (HD) and 2-dimensional (2D) 4-K ultra-HD (4K) endoscopy and their respective advantages remain unclear. Objective To evaluate the utility of these endoscopy systems in endonasal skull base surgery. Methods Consecutive series of endoscopic endonasal surgeries performed after introduction of 3D/HD and 2D/4K systems (July 2017) were retrospectively evaluated. Sporadic cases treated with either system, or a conventional 2D standard definition (SD) system, during the rental period from March 2016 were also included. Objective comparisons between the systems were made for newly diagnosed Knosp grade 0 to 3 pituitary adenomas. Surgical procedures were divided into nasal, sphenoidal, and intradural phases, and the surgical procedural time was compared for each phase. The time required for and accuracy of suturing the sellar floor dura was also evaluated. Results A total of 74 cases were treated with 3D/HD and/or 2D/4K, and 12 cases with 2D/SD. 3D/HD was advantageous in the nasal phase because of its intuitive depth perception. 2D/4K was advantageous in the intradural phase because of its superior image quality. Surgical time of the nasal phase with 3D/HD, and that of the intradural phase with 2D/4K, were significantly shorter than that with 2D/SD. The time required for and accuracy of sellar floor dural suturing showed a trend toward improving in the order of 2D/SD, 2D/4K, and 3D/HD. Conclusion 3D/HD and 2D/4K endoscopy systems have different advantages, which are useful in distinct surgical phases. Understanding the characteristics of endoscopy systems is important for selecting the most appropriate system for distinct surgical situations.

Background Reconstructive endovascular treatment is a method that can ameliorate vertebral artery dissecting aneurysm (VADA) and preserve the parent artery. Recently, 2 or 3 overlapping stents have been used to treat VADAs through the flow-diversion effect. However, little is known about the use of >3 overlapping stents for acute treatment of hemorrhagic VADA. Case Description A 69-year-old woman was admitted to our institute with the sudden onset of a headache. Brain computed tomography revealed a subarachnoid hemorrhage. Cerebral angiography revealed a VADA in the right intracranial vertebral artery. The contralateral vertebral artery was hypoplastic; thus we performed a reconstructive endovascular procedure using multiple overlapping stents combined with coiling. We used 5 overlapping stents with the aim of preventing coil herniation, fixing the jailed microcatheter, and reinforcing flow diversion and achieved immediate occlusion of the aneurysmal component. Postoperative imaging showed no apparent infarction in the brainstem. Six months after the treatment, angiography revealed complete occlusion of the aneurysm. Therefore in this case, hemorrhagic VADA was successfully treated in the acute setting by 5 overlapping Enterprise stents and coiling, which also preserved the parent artery. Conclusions Reconstructive endovascular treatment using multiple overlapping stents and coiling may be a beneficial therapy for hemorrhagic VADA, especially when the contralateral vertebral artery is aplastic or hypoplastic. Using >3 overlapping stents may represent a promising, feasible technique for achieving immediate occlusion by increasing flow diversion.

We describe a unique technique to reduce the amount of contrast medium by injecting diluted contrast medium from the microcatheter during neurointervention. A patient with severe renal impairment due to polycystic kidney was referred for endovascular surgery for wide-neck middle cerebral artery aneurysm. In order to reduce the amount of contrast medium, contrast medium was injected from the microcatheter placed in the middle cerebral artery during coil embolization; renal function decline was not observed after the procedure. This technique, therefore, reduces the amount of contrast medium and enables one to perform coil embolization safely. Key words: Chronic kidney disease, Coil embolization, Contrast medium, Contrast-induced nephropathy

Background The aneurysmal bone cyst (ABC) is a rare osteolytic lesion that is often associated with osseous disease such as fibrous dysplasia (FD). Case Description A 66-year-old woman previously diagnosed with FD presented with suddenly reduced visual acuity. Computed tomography and magnetic resonance imaging revealed a large osteolytic lesion in the middle cranial fossa that had invaded the left orbit. Although its radiological findings were compatible with an ABC, rotational digital subtraction angiography revealed that this osteolytic lesion was a large middle meningeal artery (MMA) aneurysm. To release the compression force on the optic nerve and confirm the diagnosis, we performed endovascular embolization, followed by surgical removal of the lesion. Histologic examination revealed that the resected lesion met the requirements of a thrombosed aneurysm. No new neurologic deficits appeared after the surgery, and no symptomatic recurrence have been noted during the 6-month follow-up. Conclusions This is the first case report to show that ABC-like lesions in patients with FD could be thrombosed MMA aneurysms. It is thus possible that some lesions previously diagnosed as ABCs were thrombosed MMA aneurysms or included a thrombosed MMA aneurysm. It is therefore important to rule out the presence of a MMA aneurysm when we encounter what appears to be an ABC in the presence of FD.

Interaction between the stent retriever and clot is a key factor for recanalization during mechanical thrombectomy. The aim of this study was to evaluate the association between radiographically apparent features during thrombectomy and angiographic outcomes using the Trevo stent retriever with a fully radiopaque strut.We retrospectively reviewed 50 patients with acute middle cerebral artery occlusion who were treated with the Trevo. Patients were divided into groups that achieved (first-pass recanalization group, n = 21) or did not achieve (non-first-pass recanalization group, n = 29) a modified Thrombolysis in Cerebral Ischemia score of 2b or 3 with the first-pass procedure. Patients were also divided into a thromboembolic (n = 39) and atherosclerotic (n = 11) group by occlusion etiology. We evaluated radiographic findings of the Trevo's strut (e.g., degree of stent expansion and filling defect of the thrombus in the strut [in-stent thrombus sign]) during the first-pass procedure.Median stent expansion was significantly greater in the first-pass recanalization group than in the non-first-pass recanalization group (60% vs. 34%; P0.01) and in the thromboembolic group than in the atherosclerotic group (45% vs. 31%; P0.01). The receiver operator characteristic curve showed moderate capacity for prediction of recanalization and etiology, with an area under the curve of 0.83 and 0.73, respectively. In-stent thrombus sign was significantly more common in the thromboembolic group than in the atherosclerotic group (86% vs. 10%; P0.01).Greater stent expansion was associated with recanalization after thrombectomy. The in-stent thrombus sign may be useful for etiology prediction. These radiographic findings could provide useful real-time feedback during procedures, reflecting clot-stent interaction.

Background A small number of reports have described subarachnoid hemorrhage resulting from a ruptured aneurysm embedded within a prolactinoma. To the best of our knowledge, no reports have described an embedded carotid cavernous fistula. We report a patient with carotid cavernous fistula secondary to a ruptured internal carotid artery aneurysm embedded within a prolactinoma. Case Description A 61-year-old woman was referred to our hospital with sudden headache, vomiting, and dizziness. Magnetic resonance imaging demonstrated a small acute subdural hematoma, recurrent prolactinoma, and left cavernous carotid aneurysm. Conservative therapy was initiated. Her serum prolactin level at hospitalization was 11,300 μg/L; therefore, we initiated cabergoline therapy. Twenty days after cabergoline administration, she suddenly presented with left conjunctival injection and pulsatile tinnitus. Angiography showed a left direct carotid cavernous fistula with a connection between the cavernous internal carotid artery and the cavernous sinus via the aneurysm and venous congestion. To prevent hemorrhagic stroke, we scheduled staged surgery. First, we urgently performed embolization of the cavernous sinus and fistula. One month later, to prevent aneurysm rerupture, we performed a radical operation with superficial temporal artery–middle cerebral artery double anastomosis with proximal occlusion of the left internal carotid artery at the cervical portion. The patient was discharged 2 weeks after surgery without neurological deficits. Follow-up angiography revealed complete occlusion of the aneurysm 2 months postoperatively. Conclusions An aneurysm embedded within a prolactinoma should be closely observed when cabergoline administration is started.

Objective Cerebral aneurysm growth often precedes rupture. Definite contributors to aneurysm growth have not been determined even by means of recently developed commercially available computational fluid dynamics (CFD) software. We developed an original CFD tool that can analyze data from time-of-flight magnetic resonance angiography (TOF-MRA) before growth in the growing aneurysms and investigate possible factors for aneurysm growth in the near future. Methods We retrospectively reviewed unruptured aneurysms that were treated at our institute because of aneurysm growth (growing group) between April 2013 and March 2017. Stable aneurysms that had demonstrated no growth for more than 5 years were selected (stable group). TOF-MRA data of these aneurysms were retrospectively converted to 3-dimensional vessel geometric data; 3 hemodynamic indices including streamline, wall shear stress (WSS), and oscillatory shear index were calculated by our original CFD tool using the lattice Boltzmann method to quantitatively compare the 2 groups. Results Six growing aneurysms and 6 stable aneurysms were analyzed. Of the 6 growing aneurysms, WSS on the focal aneurysmal sac increased temporally in the vicinity of the constant low WSS area at the peak systolic phase. By contrast, WSS did not increase during any part of the cardiac cycle in 3 of the 6 stable aneurysms. The peak values of WSS were significantly different between the 2 groups. Conclusions A focal increase in WSS in the peak systolic phase may be a risk factor for aneurysm enlargement in the near future.

Secure reconstruction in transsphenoidal surgery (TSS) is important for the prevention of the major and serious complication of postoperative cerebrospinal fluid (CSF) leak. Although abdominal fat can be safely and effectively used as a reconstruction tissue, harvesting it from the abdominal wall is traumatic and invasive, resulting in cosmetic problems. In this report, we present a method of harvesting abdominal fat using a minimally invasive liposuction technique to avoid cosmetic issues. Since 2016, we have been using fat harvested from the abdominal wall by suctioning with a dedicated syringe for reconstruction after TSS in selected cases. The liquefied fat obtained by the liposuction technique was wrapped with an oxycellulose sheet and changed its form to what we termed "fatty candy". In this form, the fat maintained its configuration and could be handled almost as easily as a conventional fat graft. In our experienced series, there was no case with wound complication nor postoperative or late-onset CSF leak during a postoperative follow-up of at least 3 months. The fat harvested by this simple and minimally invasive liposuction technique can be expected to provide an autologous graft that is adequate not only for prevention of cosmetic problems but also for prevention of postoperative CSF leak.

BackgroundThe prognosis of patients with advanced squamous cell carcinoma of the external auditory canal and middle ear has been improved by advances in skull base surgery and multidrug chemoradiotherapy during the last two decades.MethodsNinety-five patients with squamous cell carcinoma of the external auditory canal and middle ear who were treated between 1998 and 2017 were enrolled. The number of patients with tumour stages T1, T2, T3 and T4 was 15, 22, 24 and 34, respectively. Oncological outcomes and prognostic factors were retrospectively investigated.ResultsAmong patients with T4 disease, invasion of the brain (p = 0.024), carotid artery (p = 0.049) and/or jugular vein (p = 0.040) were significant predictors of poor prognosis. The five-year overall survival rate of patients with at least one of these factors (T4b) was significantly lower than that of patients without these factors (T4a) (25.5 vs 65.5 per cent, p = 0.049).ConclusionIt is proposed that stage T4 be subclassified into T4a and T4b according to the prognostic factors.

Structured Abstract Objective Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are recommended for high stroke-risk patients with carotid artery stenosis to reduce ischemic events. However, we often face difficulty in determining the best treatment method. Therefore, it is necessary to develop a useful decision support tool to identify an appropriate patient-specific treatment for carotid artery stenosis. Our objective is to develop an accurate post-CEA/CAS outcome prediction model using machine learning (ML) algorithms that will serve as a basis for a new decision support tool for patient-specific treatment planning. Methods Retrospectively collected data from 165 consecutive patients with carotid artery stenosis underwent CEA or CAS at a single institution were divided into training and test samples. The following six ML algorithms were tuned, and their predictive performance evaluated by comparison with surgeon predictions: an artificial neural network, logistic regression, support vector machine, Gaussian naive Bayes, random forest, and extreme gradient boosting (XGBoost). A total of 17 clinical parameters were used for the ML model development. These parameters consisted of age, pretreatment modified Rankin scale, hypertension, diabetes mellitus, medical history of arteriosclerotic disease, serum low-density lipoprotein cholesterol value, internal carotid artery peak systolic velocity, symptomatic, crescendo transient ischemic attack or stroke in evolution, previous neck irradiation, type III aorta, contralateral carotid occlusion, stenosis at a high position, mobile plaque, plaque ulceration, vulnerable plaque, and procedure (CEA or CAS). Outcome was defined as any ischemic stroke within 30 days after treatment. Results The XGBoost model performed the best in the evaluation; its sensitivity, specificity, positive predictive value, and accuracy were 66.7%, 89.5%, 50.0%, and 86.4%, respectively. The average of the outcome predictions made by four surgeons had a sensitivity of 41.7%, specificity of 75.0%, positive predictive value of 20.1%, and accuracy of 70.5%. Internal carotid artery peak systolic velocity, serum low density lipoprotein cholesterol, and procedure (CEA or CAS) were the most contributing factors according to the XGBoost algorithm. Conclusions We were able to develop a post-CEA/CAS outcome prediction model comparable to surgeons in performance. The accurate outcome prediction model will make it possible to make a more appropriate patient-specific selection of CEA or CAS for the treatment of carotid artery stenosis.

Background Microvascular decompression (MVD) is the most effective procedure for the long-term management of trigeminal neuralgia (TGN). However, retrospective and single-center studies are inherently biased, and there are currently no prospective, multicenter studies. Objective To evaluate the short- and long-term outcomes and complications in patients with TGN who underwent MVD at specialized Japanese institutions. Methods We enrolled patients with TGN who underwent MVD between April 2012 and March 2015. We recorded their facial pain grade and complications at 7 d (short term), 1 yr (mid-term), and 3 yr (long term) postoperatively. Results There were 166 patients, comprising 60 men and 106 women (mean age 62.7 yr). Furthermore, 105 patients were aged over 60 yr. We conducted neuromonitoring in 84.3% of the cases. The complete pain relief, mortality, and complication rates at the short-term follow-up were 78.9%, 0%, and 16.3%, respectively. Overall, 155 patients (93.4%) completed the long-term follow-up, with the complete pain relief and complication rates of 80.0% and 5.2%, respectively. Conclusion In the hands of experienced neurosurgeons, MVD for TGN can achieve high long-term curative effects. In addition, complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with TGN, including elderly patients.

Background The endoscopic endonasal trans-lacerum approach (EETLA) is useful in handling skull base tumors around inferior petrous apex (IPA); however, its surgical corridor is exclusively a triangular space (supra-eustachian triangle [SET]), between the internal carotid artery (ICA) and eustachian tube. Methods We investigated correlation between SET size and extent of resection around the IPA (lateral extent of resection [EOR]) through a retrospective analysis of 15 surgeries using EETLA. Results Of 15 cases (9 chordomas, 4 chondrosarcomas, and 2 meningiomas), 20 sides of IPA were affected by the tumor. When being restricted to sides with severe lateral tumor extension beyond the midpoint of petrous ICA (10 sides), the SET size was significantly broader in the group with lateral EOR of ≥90% (p value = 0.019). Conclusions The SET size was a powerful index of tumor resectability in EETLA, especially in cases with severe tumor extension. The individual anatomical variations should be considered when determining EETLA application.

The nasal cavity is the exclusive surgical corridor for endoscopic endonasal surgery; however, it is sometimes too narrow to allow extensive surgical maneuvering. Here we show the technique of submucosal inferior turbinectomy (SIT) to widen this surgical corridor. Its effectiveness is evaluated quantitatively by comparing pre- and intraoperative magnetic resonance images. Between March 2015 and October 2018, we performed endoscopic endonasal resection of 57 skull base tumors with 3T intraoperative magnetic resonance imaging (iMRI). Among these resections, cases with previous endonasal surgery and cases for which the iMRI did not cover the entire nasal cavity were excluded. Finally, six cases with and 19 cases without SIT were included in the subsequent retrospective analysis. We measured the dimensions of the narrowest area in inferior nasal cavity on pre- and intraoperative coronal plane gadolinium (Gd)-enhanced T1-weighted MR images using dedicated software, and compared them. The incidence rates of postoperative nasal complaints at outpatient clinics were also compared. Considerable widening of the inferior nasal cavity could be achieved with the SIT, which was statistically significant compared with those without the SIT (111.1 ± 56.5% vs. 39.4 ± 59.4%, respectively; P = 0.0093). In terms of the incidence rate of postoperative nasal complaints at 6 months, there was no statistical difference between the groups (33.3% vs. 15.8%, respectively; P = 0.35). SIT is effective for widening the surgical corridor while keeping nasal function and is especially helpful for lower clivus and laterally extended skull base lesions.

The Japan Neurosurgical Database (JND) is a prospective observational study registry established in 2017 by the Japan Neurosurgical Society (JNS) to visualize real-world clinical practice, promote science, and improve the quality of care and neurosurgery board certification in Japan. We summarize JND's aims and methods, and describes the 2018 survey results. The JND registered in-hospital patients' clinical data mainly from JNS training institutions in 2018. Caseload, patient demographics, and in-hospital outcomes of the overall cohort and a neurosurgical subgroup were examined according to major classifications of main diagnosis. Neurosurgical caseload per neurosurgeon in training in core hospitals in 2018 was calculated as an indicator of neurosurgical training. Of 523,283 cases (male 55.3%) registered from 1360 participating institutions, the neurosurgical subgroup comprised of 33.9%. Among the major classifications, cerebrovascular diseases comprised the largest proportion overall and in the neurosurgical subgroup (53.1%, 41.0%, respectively), followed by neurotrauma (19.1%, 25.5%), and brain tumor (10.4%, 12.8%). Functional neurosurgery (6.4%, 3.7%), spinal and peripheral nerve disorders (5.1%, 10.1%), hydrocephalus/developmental anomalies (2.9%, 5.3%), and encephalitis/infection/inflammatory and miscellaneous diseases (2.9%, 1.6%) comprised smaller proportions. Most patients were aged 70-79 years in the overall cohort and neurosurgical subgroup (27.8%, 29.4%). Neurotrauma and cerebrovascular diseases in the neurosurgical subgroup comprised a higher and lower proportion, respectively, than in the overall cohort in elderly patients (e.g. 80 years, 46.9% vs. 33.5%, 26.8% vs. 54.4%). The 2018 median neurosurgical caseload per neurosurgeon in training was 80.7 (25-75th percentile 51.5-117.5). These initial results from 2018 reveal unique aspects of neurosurgical practice in Japan.

Background: Internal carotid artery stenosis (ICS) can lead to cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, the effect of revascularization on cognitive function is controversial. In this study, we examined the resting-state functional connectivity (FC) in ICS patients undergoing revascularization surgery, with a special focus on the Default Mode Network (DMN). Methods: We prospectively enrolled 24 ICS patients, who were expecting the intervention of CEA (14 cases) or CAS (10 cases). Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessement Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and rs-fMRI were administered ≤ 1 week preoperatively and postoperatively at 1 week. For the analysis of FC, a seed was placed in the region associated with DMN. Results: After revascularization surgery, significant improvement in the score of MMSE (27.4 vs 28.4, P = 0.03) and MoCA-J (23.1 vs 25.0, P = 0.0001) was found. As for the analysis of the CAS and CEA groups, the MoCA-J score of the CEA group (24.1 vs 26.1, P = 0.001) and the MMSE score of the CAS group (26.0 vs 28.4, P = 0.01) showed statistically significant improvements. In both CAS and CEA groups, Seed-to-Voxel focusing on DMN revealed increased connectivity between medial prefrontal cortex and precuneus. Conclusion: Both CEA and CAS are associated with an improvement in neurocognitive performance and reorganization of functional connectivity, including DMN.

Background Endovascular treatment (EVT) has increasingly become the standard treatment of acute cerebral large vessel occlusion (LVO). We evaluated the impact of introducing EVT on LVO therapy in a single center where intravenous thrombolysis (IVT) had been the only recanalization therapy. Materials and methods Between April 2013 and March 2017, 354 consecutive patients with LVO admitted to our institution were analyzed. We compared outcomes between two chronological groups before (Pre-EVT group) and after (Post-EVT group) introducing EVT in April 2015. We assessed prognostic factors for favorable outcomes (modified Rankin scale score ≤2 at 90 days). Results In the Pre-EVT group, all 140 patients were treated medically, including 30 patients (21%) undergoing IVT. In the Post-EVT group, 118 patients (55%) underwent EVT, and the remaining 96 patients treated medically, including six patients (3%) undergoing IVT. The proportion undergoing recanalization therapy with IVT or EVT significantly increased after introducing EVT (21% versus 58%, p < 0.001). The rate of patients achieving favorable outcomes also significantly increased (14% versus 31%, p < 0.001). In multivariate regression analysis, introducing EVT was an independent predictive factor after adjusting for age, stroke severity and extent, and time (p = 0.005). The arrival time in patients with helicopter transport was significantly shorter than that with ground ambulance for a distance of more than 10 km (p < 0.001). Conclusions This study demonstrated that the introduction of EVT improved outcomes of acute LVO patients, increasing the opportunity to receive recanalization therapy. Further efforts to establish medical systems to provide EVT are required throughout the country., Neurology; Neurosurgery; Emergency medicine; Internal medicine; Radiology; Clinical research; Acute ischemic stroke; Large vessel occlusion; Endovascular treatment; Mechanical thrombectomy; Intravenous thrombolysis; Helicopter transport.

Background Direct oral anticoagulant (DOAC) dose is adjusted according to manufacturer's recommendations when introduced. However, subsequent changes from appropriate DOAC doses to “unintended” inappropriate low-dose DOAC (ILD) due to increased body weight (BW) or decreased serum creatinine concentration might be overlooked. We investigated outcomes in patients receiving appropriate DOAC, “intended” ILD, or unintended ILD, to determine the optimal review time for DOAC doses and associated factors. Methods This single-center, retrospective cohort study included inpatients receiving apixaban for stroke prevention between August 2015 and July 2017. Primary outcome was whether starting DOAC dose was selected according to manufacturer's recommendations and whether that dose remained appropriate thereafter. Secondary outcome was the incidence of recurrent ischemic stroke and intracranial bleeding during therapy. Average rates of change in BW, creatinine, and creatinine clearance (CrCl) were evaluated after hospitalization every 10 ± 3 days. Results During the study period, 120 patients received apixaban; 112 (93.3%) commenced appropriate DOAC doses, and 8 (6.7%) commenced intended ILD doses. Of the 112 patients on appropriate DOAC doses, 7 (6.3%) changed to unintended ILD doses because of increased BW (n = 4) or decreased creatinine (n = 3). The rate of recurrent ischemic stroke differed significantly between the appropriate DOAC dose and the intended or unintended ILD dose group (1.9% [2 of 105] versus 20.0% [3 of 15], P = .014). BW and renal function had stabilized after 20 ± 3 days posthospitalization. Conclusions Receiving ILD doses, especially unintended, might be a risk factor for recurrent ischemic stroke and DOAC dose should be reviewed around 20 ± 3 days posthospitalization.

There are very few reports in the literature associating in hydrocephalus in osteopetrosis. As a complication of shunt procedure, there are two reports on shunt malfunction due to osseous overgrowth at the burr hole in patients with osteopetrosis. We herein report a case of osteopetrosis with hydrocephalus that was successfully treated with endoscopic third ventriculostomy (ETV). At 5 months of age, a male patient presented with developmental delay. Head computed tomography (CT) demonstrated triventricular hydrocephalus with a cerebellar tonsillar herniation. At 7 months of age, he underwent suboccipital decompression with decompression of the foramen magnum. The hydrocephalus did not improve postoperatively, and the patient was transferred to our hospital. At 12 months of age, the hydrocephalus was successfully treated with ETV. The postoperative period was uneventful. Postoperative CT demonstrated an improvement in the ventricle size. The etiology of hydrocephalus in osteopetrosis is not completely understood; however, there have been several reports in which ETV was effective. ETV should be considered the treatment of choice for hydrocephalus in osteopetrosis, as it avoids the characteristic shunt complications that can occur in patients with osteopetrosis.

Objective: We report a case of a spinal dural arteriovenous fistula (s-dAVF) involving feeders from multiple intervertebral levels. Transarterial glue embolization was performed with controlling the blood flow from a feeder other than the one through which n-butyl-2-cyanoacrylate (NBCA) was injected using a balloon placed at a different level of a segmental artery. With this technique, complete occlusion was achieved with satisfactory penetration of NBCA. Case Presentation: A 57-year-old male presented with progressive gait disturbance and bladder bowel dysfunction. DSA revealed an s-dAVF fed by the right 6th, 7th, and 8th intercostal arteries (ICAs). During injection of NBCA from the radicular artery of the 6th ICA, the blood flow was controlled by occluding the feeder from the right 7th ICA with NBCA and a balloon placed at the orifice of the feeder from the right 8th ICA. Complete occlusion of the fistula was achieved by the balloon-assisted injection of NBCA. Conclusion: NBCA injection with flow control using a balloon placed in a feeder from a different segmental artery was useful for the treatment of an s-dAVF fed by multiple segmental arteries.

Focal hyperintensity (FHI) in the dorsal brain stem on T2-weighted images of patients with cerebellopontine angle (CPA) tumor was thought to indicate degeneration of the vestibular nucleus and to be specific to vestibular schwannoma. The purpose of this study was to evaluate FHI by using high-resolution 3 Tesla magnetic resonance imaging (3 T MRI) and the relation to clinical characteristics. We retrospectively reviewed the clinical data and MRI of 45 patients with CPA tumors (34 vestibular schwannomas and 11 other tumors). FHI in the dorsal brain stem was found in 25 (55.6%) patients (20 vestibular schwannomas and 5 other tumors). For the vestibular schwannomas, the factors contributing to positive FHI were age (p = 0.025), max CPA (p =

There are limited data about the prognostic factors predicting outcomes after mechanical thrombectomy with stent retrievers for the elderly. Here, we evaluated outcomes in elderly patients in a real-world setting.Between April 2015 and January 2017, 80 patients with anterior intracranial acute large vessel occlusion, who had lived independently before ictus, were treated with mechanical thrombectomy using a stent retriever at our institute. We compared outcomes between patients ≥80 years old (n = 36) and those80 years old (n = 44), and assessed prognostic factors for favorable outcomes (modified Rankin Scale score 0-2) at 90 days in all patients.There was no significant difference in baseline National Institutes of Health Stroke Scale score and Alberta Stroke Program Early Computed Tomography Score between the 2 groups. Successful revascularization (modified Thrombolysis in Cerebral Infarction [mTICI] scores 2b/3) (83% versus 93%, P = .286), complete recanalization (mTICI 3) (47% versus 50%, P = .826), and favorable outcomes (42% versus 57%, P = .261) were achieved more often in those80 years old, but differences did not reach statistical significance. Multivariate regression analysis showed that baseline National Institutes of Health Stroke Scale (P = .013) and mTICI scores of 3 (P = .006) were significant predictive factors, but being ≥80 years old and baseline Alberta Stroke Program Early Computed Tomography Score were not. In those ≥80 years old, mTICI score of 3 was an influential factor for favorable outcome (P = .017).Being aged 80 years or older was not a significant predictor for outcomes after mechanical thrombectomy, whereas complete recanalization was an influential predictor of outcome in the elderly.

Background Intracranial hemorrhage associated with cerebral hyperperfusion syndrome (CHS) is a potentially devastating complication of carotid endarterectomy (CEA) or carotid artery stenting. Intracranial hemorrhage can comprise of intracerebral hemorrhage or subarachnoid hemorrhage (SAH), but SAH after CEA is rare. We report a case of SAH associated with CHS that followed simultaneous CEA and coronary artery bypass grafting (CABG). Case description A 78-year-old man developed left-sided hemiparesis and was admitted to our institution. A preoperative study showed severe stenosis of the right carotid artery associated with markedly reduced cerebral blood flow (CBF), and a CEA was scheduled after initiating medical treatment. However, the patient developed unstable angina requiring an emergency CABG before undergoing an elective CEA. Given the risk of stroke associated with performing CABG alone, simultaneous CEA and CABG were urgently performed. The patient received dual antiplatelet therapy preoperatively and anticoagulation intraoperatively for the CABG procedure, and the anticoagulation was continued postoperatively due to the development of atrial fibrillation. Three days after the surgery, the patient developed a headache and magnetic resonance imaging demonstrated right-sided cortical SAH. Single-photon emission computed tomography revealed a significantly increased CBF. Therefore, the SAH appears to have been associated with CHS after the CEA. The hemorrhage was managed conservatively and resolved without an associated neurological deficit. Conclusion SAH after CEA is rare clinical manifestation of CHS. Simultaneous CEA and CABG, or aggressive perioperative antithrombotic therapy, may increase the risk of its occurrence. Early diagnosis and careful management are important for favorable outcomes.

It is sometimes difficult to distinguish gliomas from other tumors on routine imaging. In this study, we assessed whether 3-T magnetic resonance spectroscopy (MRS) with LCModel software might be useful for discriminating glioma from other brain tumors, such as primary central nervous system lymphomas (PCNSLs) and metastatic tumors. A total of 104 cases of brain tumor (66 gliomas, 20 PCNSLs, 6 metastatic tumors, 12 other tumors) were preoperatively investigated with short echo time (35 ms) single-voxel 3-T MRS. LCModel software was used to evaluate differences in the absolute concentrations of choline, N-acetylaspartate, N-acetylaspartylglutamate, glutamate + glutamine, myo-inositol (mIns), and lipid. mIns levels were significantly increased in high-grade glioma (HGG) compared with PCNSL (p

Therapeutic options for malignant brain tumors are limited, with new drugs being continuously evaluated. Organotypic brain slice culture has been adopted for neuroscience studies as a system that preserves brain architecture, cellular function, and the vascular network. However, the suitability of brain explants for anticancer drug evaluation has been unclear. We here adopted a mouse model of malignant glioma based on expression of H‐RasV12 in Ink4a/Arf −/− neural stem/progenitor cells to establish tumor‐bearing brain explants from adult mice. We treated the slices with cisplatin, temozolomide, paclitaxel, or tranilast and investigated the minimal assays required to assess drug effects. Serial fluorescence‐based tumor imaging was sufficient for evaluation of cisplatin, a drug with a pronounced cytotoxic action, whereas immunostaining of cleaved caspase 3 (a marker of apoptosis) and of Ki67 (a marker of cell proliferation) was necessary for the assessment of temozolomide action and immunostaining for phosphorylated histone H3 (a marker of mitosis) allowed visualization of paclitaxel‐specific effects. Staining for cleaved caspase 3 was also informative in the assessment of drug toxicity for normal brain tissue. Incubation of explants with fluorescently labeled antibodies to CD31 allowed real‐time imaging of the microvascular network and complemented time‐lapse imaging of tumor cell invasion into surrounding tissue. Our results suggest that a combination of fluorescence imaging and immunohistological staining allows a unified assessment of the effects of various classes of drug on the survival, proliferation, and invasion of glioma cells, and that organotypic brain slice culture is therefore a useful tool for evaluation of antiglioma drugs.

Objective Nasal and paranasal malignant tumors invading the skull base are rare and poorly studied. We evaluated postoperative complications in patients undergoing salvage surgery for such tumors. Design Retrospective study. Setting Kobe University Hospital. Participants Among 48 patients who underwent surgery for tumors involving the skull base between 1993 and 2015, 21 patients had squamous cell carcinoma, 13 had olfactory neuroblastoma, 5 had adenocarcinoma, 2 had sarcoma, 2 had adenoid cystic carcinoma, and 1 each had malignant melanoma, poorly differentiated carcinoma, undifferentiated carcinoma, myoepithelial carcinoma, and malignant peripheral nerve sheath tumor. Prior to skull base surgery, radiotherapy, chemoradiotherapy (CRT), particle radiotherapy, chemotherapy, or surgery were applied in 3, 15, 4, 5, and 3 patients, respectively. Main Outcome Measures Main outcome measures were postoperative complications in patients who underwent skull base surgery after concomitant CRT and/or particle therapy. Results Major postoperative complications were observed in 14 surgical procedures (29%; 2 patients with cerebral herniation, 3 with cerebrospinal fluid leakages, 3 with meningitis, 1 with hydrocephalus, 6 with epidural abscesses, 2 with local infections, and 2 with partial flap necrosis). Four patients developed ≥2 complications. One patient died of postoperative lung infarction. Three (16.7%) of 18 patients without prior treatment and 9 (50%) of 18 patients who underwent preoperative radiotherapy/CRT had severe postoperative complications. Two (50%) of four patients treated with particle radiotherapy had postoperative complications. Conclusions CRT or particle radiotherapy were significantly associated with a high risk of severe postoperative complications after skull base surgery. Meticulous care should be taken in patients treated with radiotherapy/particle therapy prior to skull base surgery.

Meningiomas within the cisterna magna without dural attachment are extremely rare. To the best of our knowledge, only three cases of meningiomas within the cisterna magna have been reported in the literature. The authors present two cases of patient with the cisterna magna meningioma without dural attachment. (Case 1) A 36-year-old female presented with a 10-month history of numbness in the left hand. Magnetic resonance imaging (MRI) disclosed the presence of a contrast-enhanced tumor in the posterior fossa. A suboccipital craniectomy was performed, and the tumor located within the cisterna magna with no attachment to the dura. Diagnosis is made as clear cell meningioma. The postoperative course was uneventful, and a recurrence has not been observed for three years. (Case 2) A 58-year-old man presented with a well-circumscribed mass in the posterior fossa. At surgery, the tumor located within the cisterna magna with a connection to the right tenia. The tumor was totally removed without neurological deficits. At a 7-year follow-up, no evidence of a recurrence was observed. It is quite difficult to preoperatively diagnose as a cisterna magna meningioma without dural attachment. However, complete removal of the tumor should be achieved.