廣瀬 雄一

BACKGROUND: To improve the outcome in newly diagnosed glioblastoma patients with maximal resection, we aimed to evaluate the efficacy and safety of implantation of carmustine wafers (CWs), radiation concomitant with temozolomide and bevacizumab, and maintenance chemotherapy with six cycles of temozolomide and bevacizumab. METHOD: This prospective phase II study enrolled glioblastoma patients considered candidates for complete resection (> 90%) of a contrast-enhanced lesion. The CWs were intraoperatively implanted into the resection cavity after achieving maximal resection. Patients without a measurable contrast-enhanced lesion on magnetic resonance imaging within 48 h after resection received concomitant radiotherapy and chemotherapy with temozolomide and bevacizumab, followed by maintenance treatment with up to six cycles of temozolomide and bevacizumab. The primary endpoint was the 2-year overall survival rate in glioblastoma patients with protocol treatment. RESULTS: From October 2015 to April 2018, we obtained consent for the first registration from 70 patients across 17 institutions in Japan, and 49 patients were treated according to the protocol. We evaluated the safety in 49 patients who were part of the second registration and the efficacy in 45 glioblastoma patients treated according to the protocol. The profile of hematological and most of the non-hematological adverse effects was similar to that in previous studies, but stroke occurred in 12% of cases (6/49 patients). The estimated 2-year overall survival rate was 51.3%. CONCLUSION: Implantation of CWs, followed by concomitant radiation, temozolomide, and bevacizumab, and six cycles of temozolomide and bevacizumab may offer some benefit to survival in Japanese glioblastoma patients with maximal resection. TRIAL ID: jRCTs021180007.

BACKGROUND AND OBJECTIVES: To the best of our knowledge, this is the first reported cadaveric feasibility study of leader-follower type robotic-assisted middle cerebral artery (MCA)-radial artery-internal carotid artery anastomosis in the neurovascular surgery field using the da Vinci Xi system (da Vinci Surgical System; Intuitive Surgical, Inc.). Vascular suturing is a necessary skill in neurosurgery; however, the learning curve for deep and high-flow bypasses is severely low. Thus, robot-assisted surgery has been introduced. Here, we describe the surgical workflow adaptations of vascular anastomosis using the da Vinci system to assess the feasibility of robot-assisted anastomoses of the radial and middle cerebral arteries. METHODS: Two fresh cadaver heads were studied using the da Vinci Xi Surgical System with 0° and 30° stereoscopic endoscopes to visualize the neuroanatomy. RESULTS: The da Vinci Xi Surgical System was used throughout the anastomosis of the MCA and intracarotid artery. The optic nerve, optic chiasm, carotid artery, and oculomotor nerve were visualized using standard microdissection techniques. The Sylvian fissure was exposed from the proximal Sylvian membrane to the distal MCA. Using black diamond microforceps and Potts scissors, suturing was achieved on the radial artery-middle cerebral artery using 8-0 Prolene and on the radial artery-internal carotid artery using 7-0 Prolene. CONCLUSION: A bypass of the MCA-radial artery-internal carotid artery can be achieved using the da Vinci Xi Surgical System in cadaver models. This system provides experts and less experienced neurosurgeons with stable bypass techniques for both superficial and deep-seated arteries. However, further studies are needed to evaluate the safety and benefits of the da Vinci Xi Surgical System for bypass procedures.

It is impossible to predict underlying anomalies in acute large vessel occlusion and it could be a problem when performing mechanical thrombectomy (MT). We report a case of MT for occlusion of the fenestrated middle cerebral artery (MCA) M1 segment. A 49-year-old woman presented to our hospital with dysarthria and left hemiparesis. Acute ischemic stroke due to right occluded MCA was diagnosed. During performing emergent MT, a part of the M1 segment was revealed to be slit-shaped by digital subtraction angiography, suggesting a fenestrated MCA. The aspiration catheter could not be advanced through the narrow limb of the fenestration, and the distal thrombus was retrieved using a stent retriever, additionally. Postoperatively, the patient's symptoms improved without complications. When occlusion of the fenestrated MCA is suspected, it is necessary to consider converting the strategy from an aspiration catheter alone to the combined use of a stent retriever.

Oligodendroglioma, IDH-mutant and 1p/19q-codeleted is known for their relative chemosensitivity and indolent clinical course among diffuse gliomas of adult type. Based on the data from phase 3 clinical trials, the standard of post-surgical care for those tumors is considered to be initial chemoradiotherapy regardless of histopathological grade, particularly with PCV. However, partly due to its renewed definition in late years, prognostic factors in patients with those tumors are not well established. Moreover, the survival rate declines over 15 years, with only a 37% OS rate at 20 years for grade 3 tumors, even with the current standard of care. Given that most of this disease occurs in young or middle-aged adults, further improvements in treatment and management are necessary. Here, we discuss prognostic factors, standard of care and chemotherapy, and future perspectives with neoadjuvant strategy in those tumors.

OBJECTIVE: The application of the da Vinci Surgical System in neurosurgery is limited due to technical difficulties requiring precise maneuvers and small instruments. This study details the advantages and disadvantages of robotics in neurosurgery and the reachable range of the transoral approach to lesions of the skull base and upper cervical spine. METHODS: In a cadaver study, the da Vinci Xi robot, lacking haptic feedback, was utilized for sagittal and coronal approaches on 5 heads, facilitating dura suturing in 3, with a 30°-angled drill for bone removal. RESULTS: Perfect exposure of all the nasopharyngeal sites, clivus, sellar, and choana, including the bilateral eustachian tubes, was achieved without any external incisions using this palatal split approach of transoral robotic surgery. The time required to perform a single stitch, knot, and complete single suture in robotic suturing of deep-seated were significantly less compared to manual suturing via the endonasal approach. CONCLUSION: This is the first report to show the feasibility of suturing the dural defect in deep-seated lesions transorally and revealed that the limit of reach in the coronal plane via a transoral approach with incision of the soft palate is the foramen ovale. This preclinical investigation also showed that the transoral robotic approach is feasible for lesions extending from the sellar to the C2 in the sagittal plane. Refinement of robotic instruments for specific anatomic sites and future neurosurgical studies are needed to further demonstrate the feasibility and effectiveness of this system in treating benign and malignant skull base lesions.

BACKGROUND: In >70% of patients with hemifacial spasm (HFS), the offending artery is either the anterior inferior cerebellar artery (AICA) or posterior inferior cerebellar artery (PICA), without a tortuous vertebrobasilar artery (VBA). We hypothesized that anchoring perforators around the root exit zone (REZ) of the AICA or PICA might induce vascular deviation and compression. We investigated the occurrence of these perforators from the AICA or PICA and the extent of VBA tortuosity to reveal the pathology of vascular compression. METHODS: This retrospective review included 110 patients after excluding those with vertebral artery (VA) compression alone. The occurrence of perforators was determined according to operative findings within 5 mm of the REZ, and VBA tortuosity was evaluated using MATLAB. We analyzed the association between perforators, VBA tortuosity, and the surgical implications. RESULTS: The occurrence of perforators from the offending AICA or PICA around the REZ was significantly higher in the group without VA compression (Group A) than in the group with VA compression (Group B). VBA tortuosity was significantly lower in Group A. VBA tortuosity was inversely correlated with the presence of AICA or PICA perforators in all 110 patients. Operative results were similar between the groups, although patients with low VBA tortuosity tended to require interposition in decompression procedures. CONCLUSIONS: Anchoring perforators around the REZ play a crucial role in vascular compression for patients with less tortuous VBAs. Moreover, surgeons should be prepared to deal with multiple perforators in a more complicated surgery in cases of less tortuous VBA.

BACKGROUND AND PURPOSE: Tumor embolization through the meningohypophyseal trunk and inferolateral trunk is known to be effective in skull-based tumors; however, microcatheter cannulation into these arteries is difficult, and the number of cases that can be safely embolized is limited. In this study, we present a novel embolization procedure for meningohypophyseal trunk and inferolateral trunk using the distal balloon protection technique and detail its clinical efficacy and complication risks. We developed this procedure to allow safe embolization in patients who cannot be adequately cannulated with microcatheters into these arteries. MATERIALS AND METHODS: Patients who underwent meningohypophyseal trunk or inferolateral trunk embolization using the distal balloon protection technique for skull-based tumors at our institution between 2010 and 2023 were included. In this procedure, the ICA was temporarily occluded with a balloon at the ophthalmic artery bifurcation, the microcatheter was guided to the meningohypophyseal trunk or inferolateral trunk vicinity, and embolic particles were injected into the arteries. The balloon was deflated after the embolic particles, that had refluxed into the ICA, were aspirated. RESULTS: A total of 25 meningohypophyseal trunks and inferolateral trunks were embolized during 21 surgeries. Of these 25 arteries, only nine (36.0%) were successfully cannulated with microcatheters. Nevertheless, effective embolization was achieved in all cases. Permanent complications occurred in only one case (4.8%), in which the central retinal artery was occluded during inferolateral trunk embolization, resulting in a visual field defect. No permanent complications resulting from the embolic cerebral infarction were observed. Of 16 cases that underwent MRI within a week after embolization, however, 11 (68.8%) demonstrated embolic cerebral infarctions. CONCLUSIONS: In patients with skull-based tumors with meningohypophyseal trunk or inferolateal trunk feeders that cannot be catheterized directly, embolization using the distal balloon protection technique for tumor supply can be considered as a salvage technique. ABBREVIATIONS: MHT = meningohypophyseal trunk; ILT = inferolateral trunk; GC = guide catheter; AC = aspiration catheter; FR = flow reverse.

BACKGROUND: In intraventricular surgery using a flexible endoscope, the lesion is usually aspirated via the working channel. However, the surgical view during aspiration is extremely poor because the objective lens is located adjacent to the working channel. METHOD: To address this issue, we developed a novel surgical procedure using an angiographic catheter. In this procedure, the catheter is inserted into the working channel, and the lesion is aspirated through the catheter. Besides, continuous intraventricular irrigation is performed via the gap between the catheter and the working channel. CONCLUSION: This procedure maintains a clear view during surgery and reduces complications.

Objective  This study compared intraoperative findings with preoperative computed tomography angiography (CTA) and computational fluid dynamics (CFD) analysis of perianeurysmal findings for the indication of possible vessel wall thinning. Materials and Methods  Participants comprised 38 patients with unruptured middle cerebral artery aneurysms treated by surgical clipping at our hospital between May 2020 and April 2021. We defined parent artery radiation sign (PARS) as the presence of each of the following three findings in CFD analysis based on preoperative CTA: (1) impingement of the stream line on the outer parent vessel wall of the aneurysm; (2) radiation of wall shear stress vectors outwards from the same site; and (3) increased wall pressure compared with the surrounding area. CFD analysis showing PARS was compared with intraoperative findings. Results  In all nine cases with PARS, no morphological abnormalities were found in the same area on CTA. However, intraoperative findings showed thinning of the parent artery wall in one of the nine cases and formation of a very small mass in three cases, differing from CTA findings. All nine patients underwent additional clipping and/or wrapping and coating at the site of PARS. Conclusion  Detecting thinning of the vessel wall or the presence of a microaneurysm may be difficult in endovascular therapy, which is based on the visualization of the vessel lumen. CFD analysis suggests the necessity of confirming findings for the vessel wall around an aneurysm by direct manipulation, as the presence of PARS may indicate partial thinning of the vessel wall or formation of a microaneurysm.

Ischemia-induced postoperative scalp necrosis in the superficial temporal artery (STA) region is known to occur after STA-middle cerebral artery anastomoses. However, no reports have evaluated the risk of postoperative scalp necrosis in the occipital artery (OA) region. This study examined the surgical procedures that pose a risk for postoperative scalp necrosis in the OA region following posterior cranial fossa surgery. Patients who underwent initial posterior fossa craniotomy at our institution from 2015 to 2022 were included. Clinical information was collected using medical records. Regarding surgical procedures, we evaluated the incision design and whether a supramuscular scalp flap was prepared. The supramuscular scalp flap was defined as a scalp flap dissected from the sternocleidomastoid and/or splenius capitis muscles. A total of 392 patients were included. Postoperative scalp necrosis occurred in 19 patients (4.8%). There were 296 patients with supramuscular scalp flaps, and supramuscular scalp flaps prepared in all 19 patients with postoperative necrosis. Comparing incision designs among patients with supramuscular scalp flap, a hockey stick-shaped scalp incision caused postoperative necrosis in 14 of 73 patients (19.1%), and the odds of postoperative scalp necrosis were higher with the hockey stick shape than with the retro-auricular C shape (adjusted odds ratio: 12.2, 95% confidence interval: 3.86-38.3, p = 0.00002). In all the cases, ischemia was considered to be the cause of postoperative necrosis. The incidence of postoperative necrosis is particularly high when a hockey stick-shaped scalp incision is combined with a supramuscular scalp flap.

Objective: The characteristics, imaging features, long-term surgical outcomes, and recurrence rates of primary spinal pilocytic astrocytomas (PAs) have not been clarified owing to their rarity and limited reports. Thus, this study aimed to analyze the clinical presentation, radiological features, pathological findings, and long-term outcomes of spinal PAs.Methods: Eighteen patients with spinal PAs who were surgically treated between 2009 and 2020 at 58 institutions were included in this retrospective multicenter study. Patient data, including demographics, radiographic features, treatment modalities, and long-term outcomes, were evaluated.Results: Among the 18 consecutive patients identified, 11 were women and 7 were men; the mean age at presentation was 31 years (3–73 years). Most PAs were located eccentrically, were solid or heterogeneous in appearance (cystic and solid), and had unclear margins. Gross total resection (GTR), subtotal resection (STR), partial resection (PR), and biopsy were performed in 28%, 33%, 33%, and 5% of cases, respectively. During a follow-up period of 65 ± 49 months, 4 patients developed a recurrence; however, the recurrence-free survival did not differ significantly between the GTR and non-GTR (STR, PR, and biopsy) groups.Conclusion: Primary spinal PAs are rare and present as eccentric and intermixed cystic and solid intramedullary cervical tumors. The imaging features of spinal PAs are nonspecific, and a definitive diagnosis requires pathological support. Surgical resection with prevention of neurological deterioration can serve as the first-line treatment; however, the resection rate does not affect recurrence-free survival. Investigation of relevant molecular biomarkers is required to elucidate the regrowth risk and prognostic factors.

Objective  Plaque induction through intimal injury using a balloon catheter in small animals and by artificial ligation of the carotid artery in large animals have been reported. However, these reports have not yet succeeded in inducing stable plaques nor creating a high degree of intimal thickening to be used as animal models. We have previously developed a plaque induction model in rats but have failed to obtain a plaque incidence frequency that can be used as a model. Thus, in the current study, we aimed to create a versatile disease model to examine the pharmacokinetics of drug administration, determine the efficacy of treatment, and examine the process of intimal thickening. We also attempted to create an improved model with shorter, more frequent, and more severe intimal thickening. Materials and Methods  The common carotid artery of male Wistar rats was surgically exposed and completely ligated with a wire and 6-0 nylon thread. Then, the wire was removed to create a partial ligation. To create a high frequency and high degree of intimal thickening, 72 rats were divided into two groups: a single lesion group with a 0.25-mm wire and a single ligature point, and a tandem lesion group with a 0.3-mm wire and two ligature points. Each group was further divided into normal diet and high cholesterol diet groups. The presence and frequency of intimal thickening were examined for each group after 4, 8, and 16 weeks of growth. Results  In the single lesion group, intimal thickening was observed in 42% of the 4-week group and 75% of the 8-week group. In the tandem lesion group, intimal thickening was observed in 75% of the 4-week group and 50% of the 8-week group. In addition, 50% of the individuals reared for 16 weeks developed intimal thickening. Conclusion  We successfully induced intimal thickening in the carotid arteries of rats with high frequency in the single lesion and tandem lesion groups. The results also showed that the tandem lesion group tended to induce intimal thickening earlier than the single lesion group.

Objective  Trigeminal neuralgia (TN) is a neurological disorder that often presents as severe toothache. The majority of TN patients visit dental clinics first, so TN represents a potential pitfall for dental practitioners. This report describes the development of a trigeminal neuralgia questionnaire (TNQ), assessing 10 characteristics of TN, to assist dentists in screening for TN in dental clinics, and evaluates the effectiveness of TNQ. Materials and Methods  Fifty-three patients who visited the TN outpatient department in our institute and completed the TNQ were included in this study. All patients were examined by two neurosurgeons and neuroimaging was performed. Statistical Analysis  Patients were classified into a TN group and a non-TN group. TNQ score was retrospectively compared between groups. Furthermore, history and characteristics of TN were investigated in the TN group to clarify the status of the reference situation. Results  Thirty-seven cases were assigned to the TN group, and 16 cases to the non-TN group. Mean TNQ score was 8.3 in the TN group and 6.6 in the non-TN group. Setting a TNQ cutoff score of 7 offered 91% sensitivity and 56% specificity for TN. Investigation of the history of the present illness indicated that 39.2% of TN cases were improperly triaged and referred from initial dental clinics, and interdisciplinary practice was insufficient. Conclusion  TNQ offers a reliable, convenient method to triage TN patients, and may assist dentists in screening for TN. Multidisciplinary practice is necessary for total management of TN and the TNQ is expected to connect dentists and TN specialists.

OBJECTIVES: Superficial temporal artery (STA) to middle cerebral artery (MCA) bypass surgery is a common treatment for preventing cerebral ischemia in patients with intracranial artery stenosis. The aim of this study was to analyze the surgical outcomes of the STA-MCA bypass procedure, particularly with regard to the invasiveness of targeted bypass (TB) with preoperative planning using Amira® software. METHODS: Consecutive patients with single STA-MCA bypass performed by a single neurosurgeon from January 2019 to May 2022 were included. The clinical parameters of seven TB patients were compared with those of 11 patients treated with the conventional method (CM). RESULTS: Compared with CM patients, TB using Amira® software patients had a shorter scalp incision (median [interquartile range]=11.2 [9.7-12.7] cm vs. 16.9 [16.0-17.7] cm, respectively; p=0.004], smaller craniotomy size (11.8 [11.5-14.4] cm2 vs. 20.9 [17.1-22.2] cm2, respectively; p=0.01], shorter surgery duration (201 [195-218] min vs. 277 [229-310] min, respectively; p=0.003], and less intraoperative bleeding (10 [10-20] g vs. 23 [20-50] g, respectively; p=0.033]. However, there were no differences in surgical complications between the two groups. CONCLUSIONS: Detailed preoperative evaluation using Amira® software can reduce the invasiveness of the STA-MCA bypass procedure.

OBJECTIVE: This retrospective study aimed to investigate factors associated with inhibition of early aneurysm obliteration after flow diverter (FD) treatment. We also created the early obliteration inhibition (EOI) score for pre-operative evaluation. METHODS: We examined 110 cerebral aneurysms in 104 patients who underwent FD treatment. The following parameters were investigated: age, sex, symptoms, aneurysm location and type, maximum aneurysm diameter, parent vessel diameter, neck diameter, and dome-neck ratio. We also noted aneurysm location relative to the curvature of the parent artery and any branches arising from the aneurysm dome. Procedural factors such as FD diameter and length, number of FDs placed, type of FD, and use of adjunctive coiling were also investigated. Aneurysm obliteration was evaluated using digital subtraction angiography 3 months after the procedure. Adequate obliteration was defined as grade C or D on the O'Kelly-Marotta scale. RESULTS: The following factors inhibited early obliteration: 1) extradural location, 2) saccular aneurysm, 3) aneurysm neck located at the outer convexity of the parent artery, and 4) arterial branch arising from the aneurysm dome. Odds ratios were used to create an EOI score. Receiver operating characteristic curve analysis showed that the optimal cut-off EOI score for adequate obliteration was 1.5 (area under the curve, 0.81; 95% confidence interval, 0.73-0.9; sensitivity, 0.9; specificity, 0.57). CONCLUSION: The EOI score, which is based on factors that inhibit early obliteration, may predict early treatment outcomes of FD placement.

BACKGROUND: Distinguishing between central nervous system lymphoma (CNSL) and CNS infectious and/or demyelinating diseases, although clinically important, is sometimes difficult even using imaging strategies and conventional cerebrospinal fluid (CSF) analyses. To determine whether detection of genetic mutations enables differentiation between these diseases and the early detection of CNSL, we performed mutational analysis using CSF liquid biopsy technique. METHODS: In this study, we extracted cell-free DNA from the CSF (CSF-cfDNA) of CNSL (N = 10), CNS infectious disease (N = 10), and demyelinating disease (N = 10) patients, and performed quantitative mutational analysis by droplet-digital PCR. Conventional analyses were also performed using peripheral blood and CSF to confirm the characteristics of each disease. RESULTS: Blood hemoglobin and albumin levels were significantly lower in CNSL than CNS infectious and demyelinating diseases, CSF cell counts were significantly higher in infectious diseases than CNSL and demyelinating diseases, and CSF-cfDNA concentrations were significantly higher in infectious diseases than CNSL and demyelinating diseases. Mutation analysis using CSF-cfDNA detected MYD88L265P and CD79Y196 mutations in 60% of CNSLs each, with either mutation detected in 80% of cases. Mutual existence of both mutations was identified in 40% of cases. These mutations were not detected in either infectious or demyelinating diseases, and the sensitivity and specificity of detecting either MYD88/CD79B mutations in CNSL were 80% and 100%, respectively. In the four cases biopsied, the median time from collecting CSF with the detected mutations to definitive diagnosis by conventional methods was 22.5 days (range, 18-93 days). CONCLUSIONS: These results suggest that mutation analysis using CSF-cfDNA might be useful for differentiating CNSL from CNS infectious/demyelinating diseases and for early detection of CNSL, even in cases where brain biopsy is difficult to perform.

The efficacy of spinal drain (SD) placement for cerebrospinal fluid (CSF) leakage prevention after the anterior transpetrosal approach (ATPA) remains unclear. Thus, we aimed to assess whether postoperative SD placement improved postoperative CSF leakage after a skull base reconstruction procedure using a small abdominal fat and pericranial flap and clarify whether bed rest with postoperative SD placement increased the length of hospital stay. This retrospective cohort study included 48 patients who underwent primary surgery using ATPA between August 2011 and February 2022. All cases underwent SD placement preoperatively. First, we evaluated the necessity of SD placement for CSF leakage prevention by comparing the postoperative routine continuous SD placement period to a period in which the SD was removed immediately after surgery. Second, the effects of different SD placement durations were evaluated to understand the adverse effects of SD placement requiring bed rest. No patient with or without postoperative continuous SD placement developed CSF leakage. The median postoperative time to first ambulation was 3 days shorter (P < 0.05), and the length of hospital stay was 7 days shorter (P < 0.05) for patients who underwent SD removal immediately after surgery (2 and 12 days, respectively) than for those who underwent SD removal on postoperative day 1 (5 and 19 days, respectively). This skull base reconstruction technique was effective in preventing CSF leakage in patients undergoing ATPA, and postoperative SD placement was not necessary. Removing the SD immediately after surgery can lead to earlier postoperative ambulation and shorter hospital stay by reducing medical complications and improving functional capacity.

Primary optic nerve sheath meningioma (pONSM) is one of the most challenging tumors to manage. Although surgical excision may be considered a treatment option to maintain visual function, the safety of surgery remains debatable due to the non-negligible risk of optic nerve injury. pONSM often grows concentrically around the optic nerve; however, it can also demonstrate an exophytic growth from the optic nerve. The risk of surgical excision of pONSM may vary based on the tumor's growth pattern and area of contact with the optic nerve; however, there has been no detailed report on risk stratification to date. The authors present an illustrative case of an exophytic pONSM which was removed surgically without complications, suggesting that tumor morphology may also influence the surgical risk. In this report, the imaging and intraoperative features of exophytic pONSM are presented in detail, and the risk factors for complications are discussed.

BACKGROUND: The Uncal vein (UV), downstream of the deep middle cerebral vein (DMCV), has a similar drainage pattern to the superficial middle cerebral vein (SMCV) and may be involved in venous complications during the anterior transpetrosal approach (ATPA). However, in petroclival meningioma (PCM), where the ATPA is frequently used, there are no reports evaluating drainage patterns of the UV and the risk of venous complications associated with the UV during the ATPA. METHODS: Forty-three patients with petroclival meningioma (PCM) and 20 with unruptured intracranial aneurysm (control group) were included. Preoperative digital subtraction angiography was used to evaluate UV and DMCV drainage patterns on the side of the tumor and bilaterally in patients with PCM and the control group, respectively. RESULTS: In the control group, the DMCV drained to the UV, UV and BVR, and BVR in 24 (60.0%), eight (20.0%), and eight (20.0%) hemispheres, respectively. Conversely, the DMCV in the patients with PCM drained to the UV, UV and BVR, and BVR in 12 (27.9%), 19 (44.2%), and 12 (27.9%) patients, respectively. The DMCV was more likely to be drained to the BVR in the PCM group (p < 0.01). In three patients with PCM (7.0%), the DMCV drained only to the UV, and furthermore, the UV drained to the pterygoid plexus via the foramen ovale, posing a risk for venous complications during the ATPA. CONCLUSIONS: In the patients with PCM, the BVR functioned as a collateral venous pathway of the UV. Preoperative evaluation of the UV drainage patterns is recommended to reduce venous complications during the ATPA.

Fence-post catheter techniques are used to use tumor margins when resecting gliomas. In the present study, deep electrodes instead of catheters were used as fence-posts. The case of a 25-year-old female patient whose magnetic resonance images (MRI) revealed a tumor in the left cingulate gyrus is presented in this study. She underwent daily seizures without loss of consciousness under the administration of anti-seizure medications. Despite video electroencephalography (EEG) monitoring, the scalp inter-ictal EEG did not show obvious epileptiform discharges. We were consequently uncertain whether such frequent seizures were epileptic seizures or not. As a result, deep electrodes were used as fence-posts: three deep electrodes were inserted into the tumor’s anterior, lateral, and posterior margins using a navigation-guided method. The highest epileptic discharge was detected from the anterior deep electrode. As a result, ahead of the tumor was extendedly resected, and epileptic discharges were eliminated using EEG. The postoperative MRI revealed that the tumor was resected. The patient has never experienced seizures after the surgery. In conclusion, when supratentorial gliomas complicated by frequent seizures are resected, intraoperative EEG monitoring using deep electrodes as fence-posts is useful for estimating epileptogenic areas.

OBJECTIVE: Although a qualitative diagnosis of plaque causing carotid stenosis has been attempted with carotid computed tomography angiography (CaCTA), no clear findings have been reported. We examined the correlation between the plaque CT values and plaque images obtained by magnetic resonance imaging to derive a qualitative diagnosis of the plaque using CaCTA. METHODS: Preoperative CaCTA images acquired from patients stented for carotid stenosis were retrospectively analyzed with respect to magnetization-prepared rapid acquisition with gradient echo and time-of-flight magnetic resonance angiography data. Carotid plaques in the stenosed region were quantified in terms of CT density and the plaque/muscle ratio (magnetization-prepared rapid acquisition with gradient echo), and correlations between these 2 features were determined. Plaques were classified as stable or unstable based on the plaque/muscle ratio, with the smallest plaque/muscle ratio observed among plaques positive for intraplaque hemorrhage set as the cutoff value (1.76). RESULTS: A total of 165 patients (179 plaques) were included. Perioperative complications included minor stroke (n = 3), major stroke (n = 1, fatal), and hyperperfusion (n = 2). The correlation between CT density and the plaque/muscle ratio was nonlinear (P = 0.0139) and negative (P < 0.0001). The cutoff point (1.76) corresponded to a CT density of 83 HU, supporting this value as a standard reference for plaque stability. CONCLUSIONS: Computed tomography density exhibits a nonlinear (P = 0.0139) and highly negative correlation (P < 0.0001) with the plaque/muscle ratio. Our results demonstrate that plaque characteristics can be meaningfully diagnosed based on CaCTA image data.

BACKGROUND: For endoscopic endonasal surgery of pituitary tumors, tissue identification and intraoperative judgment depend largely on surgeon expertise. In the present study, we assess whether the delayed-window indocyanine green (ICG) technique can identify pituitary gland tumors in real-time during surgery and analyze the mechanism of ICG fluorescence in the pituitary gland and tumor. METHODS: Twenty-five patients with a pituitary adenoma were administered 12.5 mg of ICG intravenously during surgery. Thereafter, near-infrared (NIR) visualization was performed from 0 to 180 minutes. Only 8 patients underwent dynamic contrast-enhanced perfusion magnetic resonance imaging (MRI) owing to predicaments with insurance coverage. Consequently, we analyzed these 8 patients extensively. RESULTS: The pituitary gland and pituitary adenoma were visualized in all 25 patients with NIR fluorescence. The relative ratio of the fluorescence emission of the normal gland to that of the tumor (signal/background ratio [SBR] of the normal gland vs. the tumor) had increased after 15 minutes, peaking (5.8) at 90 minutes, demonstrating that the pituitary gland was distinctly visualized during that period. The tumor/blood (SBR tumor) and normal gland/blood (SBR gland) NIR fluorescence was significantly and positively correlated with each transfer constant on dynamic contrast-enhanced MRI, indicating vascular permeability. CONCLUSIONS: The results from the present study exhibit the utility of the delayed-window ICG technique in distinguishing the normal pituitary gland from a tumor during endoscopic endonasal surgery from 15 to 90 minutes after ICG administration. Permeability can contribute to gadolinium enhancement on MRI, as well as ICG retention and NIR fluorescence in a normal pituitary gland and tumor.

Vagus nerve stimulation (VNS) is an effective surgical option for intractable epilepsy. Although the surgical procedure is not so complicated, vagus nerve detection is sometimes difficult due to its anatomical variations, which may lead to surgical manipulation-associated complications. Thus, this study aimed to visualize the vagus nerve location preoperatively by fused images of three-dimensional computed tomography angiography (3D-CTA) and magnetic resonance imaging (MRI). This technique was applied to two cases. The neck 3D-CTA and MRI were performed, and the fused images were generated using the software. The vagus nerve and its anatomical relationship with the internal jugular vein (IJV) and common carotid artery were clearly visualized. The authors predicted that the vagus nerve was detected by laterally pulling the IJV according to the images. Intraoperatively, the vagus nerve was located as the authors predicted. The time of the surgery until the vagus nerve detection was &lt;60 min in both cases. This novel radiological technique for visualizing the vagus nerve is effective to quickly detect the vagus nerve, which has anatomical variations, during the VNS.

OBJECTIVE: Although amide proton transfer-weighted (APTw) imaging is reported by 2-dimensional (2D) spin-echo-based sequencing, 3-dimensional (3D) APTw imaging can be obtained by gradient-echo-based sequencing. The purpose of this study was to compare the efficacy of APTw imaging between 2D and 3D imaging in patients with various brain tumors. METHODS: A total of 49 patients who had undergone 53 examinations [5 low-grade gliomas (LGG), 16 high-grade gliomas (HGG), 6 malignant lymphomas, 4 metastases, and 22 meningiomas] underwent APTw imaging using 2D and 3D sequences. The magnetization transfer ratio asymmetry (MTRasym) was assessed by means of region of interest measurements. Pearson correlation was performed to determine the relationship between MTRasym for the 2 methods, and Student's t test to compare MTRasym for LGG and HGG. The diagnostic accuracy to differentiate HGG from LGG of the 2 methods was compared by means of the McNemar test. RESULTS: Three-dimensional APTw imaging showed a significant correlation with 2D APTw imaging (r = 0.79, P < 0.0001). The limits of agreement between the 2 methods were -0.021 ± 1.42%. The MTRasym of HGG (2D: 1.97 ± 0.96, 3D: 2.11 ± 0.95) was significantly higher than those of LGG (2D: 0.46 ± 0.89%, P < 0.01; 3D: 0.15 ± 1.09%, P < 0.001). The diagnostic performance of the 2 methods to differentiate HGG from LGG was not significantly different (P = 1). CONCLUSIONS: The potential capability of 3D APTw imaging is equal to or greater than that of 2D APTw imaging and is considered at least as valuable in patients with brain tumors.

Distinguishing primary central nervous system lymphoma (PCNSL) from glioblastoma, isocitrate dehydrogenase (IDH)-wildtype is sometimes hard. Because the role of operation on them varies, accurate preoperative diagnosis is crucial. In this study, we evaluated whether a specific kind of chemical exchange saturation transfer imaging, i.e., amide proton transfer-weighted (APTw) imaging, was useful to distinguish PCNSL from glioblastoma, IDH-wildtype. A total of 14 PCNSL and 27 glioblastoma, IDH-wildtype cases were evaluated. There was no significant difference in the mean APTw signal values between the two groups. However, the percentile values from the 1st percentile to the 20th percentile APTw signals and the width1–100 APTw signals significantly differed. The highest area under the curve was 0.796, which was obtained from the width1–100 APTw signal values. The sensitivity and specificity values were 64.3% and 88.9%, respectively. APTw imaging was useful to distinguish PCNSL from glioblastoma, IDH-wildtype. To avoid unnecessary aggressive surgical resection, APTw imaging is recommended for cases in which PCNSL is one of the differential diagnoses.

Evacuation of middle fossa trigeminal schwannomas (TS) warrants a subtemporal interdural approach through the lateral wall of the cavernous sinus (CS). The dura comprises the dura propria, which follows the trigeminal nerve and develops into the epineurium, and periosteal layer. The interdural approach involves peeling off the dura propria and exposing the epineural sheath. The venous route around the CS is often obstructed due to TS progression. The interdural approach based on venous route preservation remains to be discussed. The laterocavernous sinus (LCS) is formed in these layers, draining to either the medial or lateral route. In the lateral route, the LCS drains to the pterygoid plexus via the middle cranial fossa foramen. Exposure of the interdural space disturbs the lateral route's venous flow. We describe an operative strategy for venous route preservation in TS via the LCS lateral route. The venous route can be preserved by peeling off the dura propria from the posterior end of the foramen ovale short of the venous drainage route to the pterygoid plexus epidurally and then cutting from the middle cranial fossa dura posterior to the venous route subdurally to the exposed interdural space. This technique helps in avoiding postoperative venous complications.

Abstract Background In glioma surgery, both of functional preservation and maximal safe resection are critical, however, neoadjuvant strategy has never been used because of difficulty of tissue sampling without craniotomy. Method In Keio University Hospital, oligodendrogliomas, i.e., diffuse gliomas with IDH mutation and 1p/19q codeletion, with incomplete initial resection have been treated by upfront chemotherapy and subsequent resection after tumor volume decrease (second look resection, SLR) since 2006 (J Neurooncol 124:127-35, 2015). At first, initial radiotherapy was prescribed immediately after chemotherapy or SLR only for the cases with aggressive clinical course or subarachnoid infiltration, however, cases with residual FLAIR abnormality after upfront chemotherapy or SLR were also subjected to initial radiotherapy since 2018. Cases 1) with IDH mutation and 1p/19q codeletion, and 2) without history of either chemotherapy or radiotherapy, and 3) treated with upfront chemotherapy and subsequent resection strategy, were included. Results Thirty nine cases of oligodendroglioma have been treated with the above strategy since 2006. Tumor volume decrease following upfront chemotherapy was 30-35% (median), and 19 tumors underwent SLR. Among the total 39 cases, PFS and OS after initiation of upfront chemotherapy were 81 months and not reached, respectively, and were 64 months and not reached, respectively, among the 32 cases with deferred radiotherapy. Importantly, the majority of tumor recurrence occurred at the residual FLAIR abnormality following upfront chemotherapy. Conclusions Treatment of oligodendrogliomas utilizing neoadjuvant strategy enables 1) decrease of resection volume as compared with initial maximal safe resection, 2) more precise resection, 3) confirmation of the necessity of initial radiotherapy based on the observed efficacy of chemotherapy. Moreover, the study also suggested that 4) invasion front of oligodendroglioma likely withdraw by alkylating agents, and 5) cases with residual FLAIR abnormality following chemotherapy may be appropriate subjects for initial radiotherapy.

Abstract Introduction The utility of intraoperative real-time fluorescent navigation of indocyanine green (ICG) for cerebrospinal tumors has been demonstrated in gliomas, schwannomas, and meningiomas. We reported the usefulness of the existing Second window ICG (SWIG) for metastatic brain tumors, in which 5 mg/kg is administered 24 hours before the day before surgery. Subsequently, we developed a Delayed window ICG (DWIG) administered 1 hour before observation intraoperatively and report our experience. Methods The subjects were 28 patients from August 2019 to March 2022, with an average age of 67 years, diagnosed with metastatic brain tumors. Eighteen patients were in the SWIG group and 10 in the DWIG group. Iridium (Visionsense) and KINEVO (Carl Zeiss) were used for near-infrared irradiation and observation. Results Near-infrared light was irradiated during surgery, and in all cases, fluorescence from the tumor was confirmed. Fluorescence emission could be confirmed as far as 10 mm from the brain surface. The Signal Background Ratio (SBR) of tumor to brain parenchyma was 3.4 in SWIG and 4.2 in DWIG. There is no significant difference between them.(P=0.15) All patients had contrast areas on preoperative contrast MRI, and the ratio of contrast area to brain parenchyma (T1BR) was 2.5. After intraoperative resection, all resected patients showed no contrast lesions on immediate postoperative MRI. No perioperative complications due to I CG administration were noted. Conclusions Metastatic tumors may be difficult to distinguish from the normal brain visually due to the inaccuracy of the navigation system caused by intraoperative brainshift and blurring of the boundaries under an optical microscope. Intraoperative fluorescence angiography is useful in such cases because it allows tumor localization and removal in real time. DWIG is useful for metastatic brain tumors because it is simple and easy to use, with no significant difference compared to existing SWIG.

Unruptured cerebral aneurysms (UCAs) are usually asymptomatic and detected incidentally by intracranial examinations. The coexistence of neurovascular compression syndrome (NVCS) and UCAs has not been well described. The aim of this study was to clarify the characteristics of UCAs with the NVCS. A total of 103 cases that underwent microvascular decompression (MVD) for trigeminal neuralgia (TN) or hemifacial spasm (HFS) were assigned to the NVCS group. The prevalence of UCAs in the NVCS group was compared retrospectively to that in 110 control cases (a control group) by neuro-imaging. Overall treatment courses for NVCS and UCAs were investigated in the NVCS group. Sixteen (15.3%; TN 11 cases, HFS 5 cases) of 103 MVD cases had 19 UCAs, a significantly higher prevalence than the 3.6% in the control group. Binomial logistic regression showed that NVCS is a significant factor for predicting the presence of UCAs, with an odds ratio of 4.80. In the NVCS group, 18 UCAs (94.7%) were supratentorial aneurysms, and 17 UCAs (89.5%) were less than 5 mm in size. Nine UCAs were surgically treated with clipping or coiling. Of the surgical cases, 2 UCAs were treated before MVD for NVCS, whereas the other 7 UCAs were treated after MVD. No aneurysms ruptured during the treatment course. The NVCS occurred with UCAs at a significantly higher rate than in the control group. Most UCAs with the NVCS were supratentorial, small aneurysms that did not affect the surgical treatment of NVCS.

OBJECTIVES: This study aimed to determine the impact of the approval of prothrombin complex concentrates on the treatment of vitamin K antagonist-related intracerebral hemorrhage. MATERIALS AND METHODS: We retrospectively studied all patients with vitamin K antagonist-related intracerebral hemorrhage treated with prothrombin complex concentrate at our institutes between January 2010 and June 2021. Before approval, prothrombin complex concentrate was administered as either 500 or 1000 IU at the physician's discretion (previous dose group). After approval, we adopted the manufacturer's recommended regimen (recommended dose group). The primary outcome was post-administration international normalized ratio. Secondary outcomes were the amount of prothrombin complex concentrate administered and proportion of post-administration international normalized ratio <1.5, hematoma expansion, thrombotic events within 30 days, modified Rankin scale 0-3 at discharge, and in-hospital mortality. RESULTS: Thirty-two and 19 patients in the previous and recommended dose groups, respectively, were included. The post-administration international normalized ratio significantly differed between groups. The prothrombin complex concentrate dose and proportion of patients achieving post-administration international normalized ratio <1.5 were significantly higher in the recommended dose group than in the previous dose group (1500 IU vs. 500 IU, p<0.001 and 100% vs. 68%, p = 0.008). The proportions of hematoma expansion, thromboembolic events, modified Rankin scale 0-3, and mortality did not differ between groups. CONCLUSION: After prothrombin complex concentrate approval, prothrombin time-international normalized ratio correction was more effective with a significant increase in the prothrombin complex concentrates dose for vitamin K antagonist-associated intracerebral hemorrhage; however, there was no apparent difference in clinical outcomes.

BACKGROUND: Diploic veins may act as collateral venous pathways in cases of meningioma with venous sinus invasion. Diploic vein blood flow should be preoperatively evaluated to consider preserving the veins. In this study, we evaluated the use of time-resolved whole-head computed tomography angiography (4D-CTA)-which is less patient-intensive than digital subtraction angiography (DSA)-for assessing diploic vein blood flow and the positional relationship between typical craniotomy approaches and diploic veins. METHODS: We retrospectively examined 231 patients who underwent surgery for intracranial meningioma. We performed contrast-enhanced magnetic resonance imaging (MRI) to evaluate diploic vein pathways and compared the visualization rates of diploic vein blood flow assessed using 4D-CTA and DSA. Subsequently, we evaluated the rates of the diploic veins transected during craniotomy by comparing the pre- and postoperative contrast-enhanced MRI. RESULTS: The diagnostic performance of 4D-CTA was assessed in 45 patients. Of the 320 diploic veins identified in these patients, blood flow in 70 (21.9%) diploic veins was identified by 4D-CTA and DSA, and both results were consistent. To assess the transection rates of the diploic veins, 150 patients were included. A trend towards a high transection rate of the diploic vein in the basal interhemispheric, frontotemporal, orbitozygomatic, combined transpetrosal, and convexity craniotomy approaches was observed. CONCLUSIONS: In patients with meningiomas, both 4D-CTA and DSA are useful in evaluating diploic vein blood flow. In meningiomas with venous sinus invasion, determining the extent of craniotomy after understanding the pathways and blood flow of diploic veins is recommended.

Objectives: The benefit of mechanical thrombectomy for acute ischemic stroke is highly time dependent. However, time to treatment is longer for in-hospital stroke patients than community-onset stroke patients. This study aimed to clarify the cause of this difference. Methods: A retrospective single-center study was performed to analyze patients with large vessel occlusion who underwent mechanical thrombectomy between January 2017 and December 2019. Patients were divided into in-hospital stroke and community-onset stroke groups. Clinical characteristics and treatment time intervals were compared between groups. Results: One hundred four patients were analyzed: 17 with in-hospital stroke and 87 with community-onset stroke. Patient characteristics did not significantly differ between groups. Median door (stroke recognition)-to-computed tomography time (36 min vs. 14 min, P<0.01) and door-to-puncture time (135 min vs. 117 min, P=0.02) were significantly longer in the in-hospital stroke group than the community-onset stroke group. However, median computed tomography-to-puncture time (104 min vs. 104 min, P=0.47) and puncture-to-reperfusion time (53 min vs. 38 min, P=0.17) did not significantly differ. Conclusions: Longer door-to-puncture time in in-hospital stroke patients was mostly caused by longer door-to-computed tomography time, which is the initial part of the workflow. An in-hospital stroke protocol that places importance on early stroke specialist consultation and prompt transportation to the computed tomography scanner might hasten treatment and improve outcomes in patients with in-hospital stroke.

Most osteomalacia-inducing tumors (OITs) are phosphaturic mesenchymal tumors (PMTs) that secrete fibroblast growth factor 23 (FGF23). These tumors usually occur in the bone and soft tissues, and intracranial OITs are rare. Therefore, intracranial OIT is difficult to diagnose and treat. This paper presents a case of intracranial OIT and shows a review of previous cases. A 45-year-old man underwent nasal cavity biopsy and treatment with active vitamin D3 and neutral phosphate for hypophosphatemia. Amplification of FGF23 mRNA level within the tumor was detected. Subsequently, the surgical specimen was diagnosed with a PMT and was considered the cause of the patient's osteomalacia. The patient was referred to a neurosurgery department for the excision of the intracranial tumor extending to the nasal cavity. After tumor removal, the serum levels of FGF23 and phosphorus were normalized as compared to preoperative those. The patient remains disease-free, without additional treatment, approximately 10 years after surgery, with no tumor recurrence. As per the literature, intracranial OITs usually occur in patients aged 8-69 years. Bone and muscle pain are major complaints. Approximately 60% of the patients reported previously had symptoms because of intracranial tumors. In some cases, it took several years to diagnose OIT after the onset of the osteomalacia symptoms. Laboratory data in such cases show hypophosphatemia and elevated FGF23 levels. Because FGF23 levels are associated with the severity of osteomalacia symptoms, total tumor resection is recommended. PMT and hemangiopericytoma (HPC) are histologically similar, but on immunochemistry, PMT is negative for signal transducer and activator of transcription 6 (STAT6), whereas HPC is positive. FGF23 amplification is seen in PMTs but not in HPCs. Therefore, the analysis of FGF23 and STAT6 was helpful in distinguishing PMTs from HPCs. In cases of hypophosphatemia and osteomalacia without a history of metabolic, renal, or malabsorptive diseases, the possibility of oncogenic osteomalacia should be considered.

Cyst formation in the third ventricle and the histopathological findings were rarely reported. We report a similar case of late-onset aqueductal membranous occlusion (LAMO) caused by a thin gliotic cyst and a review of related literature. A 28-year-old woman with enlarged lateral ventricles was referred to our hospital with complaints of headache and dizziness. In our hospital, the obvious cause of the hydrocephalus was unknown on any examination and we decided performing endoscopic third ventriculostomy for hydrocephalus. A thin cyst covering the entrance of the aqueduct was identified and we perforated it. Histopathological finding of the cyst wall was gliosis and our case was similar to LAMO, although not typical. The postoperative symptoms and ventricle size improved for 4 years. When suspecting cases similar to definition of LAMO, neuroendoscopic surgery would be the first-choice treatment and might detect causes undetectable on preoperative imaging such as our thin membrane.

Meningiomas are a common pathology in the central nervous system requiring complete surgical resection. However, in cases of recurrence and post-irradiation, accurate identification of tumor remnants and a dural tail under bright light remains challenging. We aimed to perform real-time intraoperative visualization of the meningioma and dural tail using a delayed-window indocyanine green (ICG) technique with microscopy. Fifteen patients with intracranial meningioma received 0.5 mg/kg ICG a few hours before observation during the surgery. We used near-infrared (NIR) fluorescence to identify the tumor location. NIR fluorescence could visualize meningiomas in 12 out of 15 cases. Near-infrared visualization during the surgery ranged from 1 to 4 h after the administration of ICG. The mean signal-to-background ratio (SBR) of the intracranial meningioma in delayed-window ICG (DWIG) was 3.3 ± 2.6. The ratio of gadolinium-enhanced T1 tumor signal to the brain (T1BR) (2.5 ± 0.9) was significantly correlated with the tumor SBR (p = 0.016). K^trans, indicating blood–brain barrier permeability, was significantly correlated with tumor SBR (p &amp;lt; 0.0001) and T1BR (p = 0.013) on dynamic contrast-enhanced magnetic resonance imaging (MRI). DWIG demonstrated a sensitivity of 94%, specificity of 38%, positive predictive value (PPV) of 76%, and negative predictive value (NPV) of 75% for meningiomas. This is the first pilot study in which DWIG fluorescence-guided surgery was used to visualize meningioma and dural tail intraoperatively with microscopy. DWIG is comparable with second-window ICG in terms of mean SBR. Gadolinium-enhanced T1 tumor signal may predict NIR fluorescence of the intracranial meningioma. Blood–brain barrier permeability as shown by K^trans on dynamic contrast-enhanced MRI can contribute to gadolinium enhancement on MRI and to ICG retention and tumor fluorescence by NIR.

This case showed a 13-year-old boy presented with calvarium subperiosteal hematoma crossing the suture lines caused by hair pulling, and 3D-CTV can differentiate calvarium subperiosteal hematoma crossing the suture lines from subgaleal hematoma. He was treated successfully.

Introduction  Preoperative illustration is a part of an important exercise to study the configuration, direction, and presence of any perforations, and is the weakest point in the wall of the cerebral aneurysm. The same illustration is used to study the surrounding brain structures to decide the best and safe surgical approach prior to any surgical procedure. With the evolution of the aneurysm wall study and study of flow dynamic within the involved artery and its aneurysm wall using computational fluid dynamics (CFD), a better surgical plan can be formulated to improve the flow dynamics. As one of the clinical applications of CFD, we propose a study using a composite image that combines preoperative illustration and CFD, which is traditionally widely used in neurosurgery. Methods and Materials  We study the use of illustrations of the unruptured cerebral aneurysm of internal carotid-posterior communicating (ICPC) artery and anterior communicating artery (AcomA) treated at our hospital. The combinations of both preoperative illustrations and CFD images by using "ipad Pro" were used. Result and Conclusion  Medical illustration in the preoperative study of unruptured cerebral aneurysm with combinations of CFD and surrounding brain structures is helpful to decide the surgical approaches and successful surgical treatments.