AB004. Transsylvian approach for radical resection of insular gliomas: emphasizing the importance of the transsylvian approach for elderly patients with Zone II and III insular gliomas.

BACKGROUND: Insular gliomas present significant challenges due to their deep-seated location and proximity to critical structures, including sylvian veins, middle cerebral arteries (MCAs), lenticulostriate arteries, long insular arteries, and functional cortices and white matter tracts. The Berger-Sanai classification categorizes them into four zones (I-IV), providing a framework for understanding insular gliomas. The key factors for successful insular glioma removal are achieving the greatest insular exposure and surgical freedom. There are two main types of approach methods, such as transsylvian approach with meticulous wider dissection of the sylvian fissure and transcorticosubcortical approach with intraoperative functional brain mapping under awake surgery to remove the functionally silent cortices and white matter tracts. Because splitting the distal sylvian fissure is more challenging, a transcortical approach through the parietorolandic operculum in awake patients has been reported to be more effective access to the posterior insular gliomas (Zone II and III) in the dominant hemisphere. The object of this study emphasize the importance of the transsylvian approach for radical resection of insular gliomas. METHODS: We retrospectively analyzed our experiences with radically resected insulo-opercular gliomas. Basically, we pursue the transsylvian approach for resecting insular gliomas without removal of any normal brain. RESULTS: Motor pathways running beneath the parietorolandic operculum can be damaged by ischemia caused by sacrificing the medullary arteries (MAs) arising from the pial arteries of the M3 and M4 portions of the MCA. Motor deficit after resection of this area was significantly found in the elderly patients. This phenomenon might be described by the age-associated decreasing the vascular reserve capacity. Autopsy brains showed that the sclerotic rate of the MAs increased with age and hypertension. Even with the intraoperative functional brain mapping, we cannot avoid the ischemic complication caused by sacrificing the MAs during stepwise removal of the functionally silent cortices and white matter tracts. CONCLUSIONS: We make a suggestion not to remove the parietorolandic operculum in elderly patients with insular gliomas located at Zone II and III. Distal transsylvian approach should be applied.

Protocol digest of a phase III randomized trial of gross total resection versus possible resection of fluid-attenuated inversion recovery-hyperintense lesion on MRI for newly diagnosed supratentorial glioblastoma: JCOG2209 (FLAMINGO).

The goal of surgery for patients with newly diagnosed glioblastoma (GBM) is maximum safe resection of the contrast-enhancing (CE) lesion on magnetic resonance imaging. However, there is no consensus on the efficacy of FLAIRectomy, which is defined as the possible resection of fluid-attenuated inversion recovery (FLAIR)-hyperintense lesions surrounding the CE lesion. Although retrospective analyses suggested the potential benefits of FLAIRectomy, such outcomes have not been confirmed by prospective studies. Therefore, we planned a multicenter, open-label, randomized controlled phase III trial to evaluate the efficacy of FLAIRectomy compared with gross total resection of CE lesions in patients with newly diagnosed GBM. The primary endpoint is overall survival. In total, 130 patients will be enrolled from 47 institutions over 5 years. This trial has been registered at the Japan Registry of Clinical Trials (study number jRCT1031230245).

Clinical significance of cerebral microbleeds in patients with germinoma who underwent long-term follow-up.

PURPOSE: This study identified the factors affecting cerebral microbleed (CMBs) development. Moreover, their effects on intelligence and memory and association with stroke in patients with germinoma who had long-term follow-up were evaluated. METHODS: This study included 64 patients with germinoma who were histologically and clinically diagnosed with and treated for germinoma. These patients were evaluated cross-sectionally, with a focus on CMBs on susceptibility-weighted magnetic resonance imaging (SWI), brain atrophy assessed through volumetric analysis, and intelligence and memory. RESULTS: The follow-up period was from 32 to 412 (median: 175.5) months. In total, 43 (67%) patients had 509 CMBs and 21 did not have CMBs. Moderate correlations were observed between the number of CMBs and time from initial treatments and recurrence was found to be a risk factor for CMB development. Increased temporal CMBs had a marginal effect on the processing speed and visual memory, whereas brain atrophy had a statistically significant effect on verbal, visual, and general memory and a marginal effect on processing speed. Before SWI acquisition and during the follow-up periods, eight strokes occurred in four patients. All of these patients had ≥ 15 CMBs on SWI before stroke onset. Meanwhile, 33 patients with < 14 CMBs or 21 patients without CMBs did not experience stroke. CONCLUSION: Patients with a longer time from treatment initiation had a higher number of CMBs, and recurrence was a significant risk factor for CMB development. Furthermore, brain atrophy had a stronger effect on memory than CMBs. Increased CMBs predict the stroke onset.

Complete removal of a cavernous malformation in the dorsal pons, in contact with the expanded transpontine vein: illustrative case.

BACKGROUND: Craniotomy is required for the removal of brainstem cavernous malformations (CMs) with repeated hemorrhage, and this condition is often complicated by an accompanying developmental venous anomaly (DVA). However, a DVA of the brainstem or cerebellum with drainage penetrating the pons is an exceptional finding. OBSERVATIONS: A 57-year-old man presented with double vision. Computed tomography revealed progressive enlargement of the hemorrhage in the dorsal pons. Contrast-enhanced magnetic resonance angiography revealed an expanded transverse vessel penetrating the center of the pons in contact with the CM. Digital subtraction angiography revealed that the DVA, comprising the expanded transpontine vein and some cerebellar medullary veins acting as normal venous drainage, coexisted with the CM. By utilizing the angioarchitecture and intraoperative neuronavigation system data, electrophysiological mapping, and indocyanine green videoangiography, complete removal of the CM was accomplished while preserving the DVA and brain function. LESSONS: This study presents the intraoperative images of an expanded transpontine vein as a DVA, which has never been depicted in a live patient before, accompanied by a CM in the dorsal portion of the pons. https://thejns.org/doi/10.3171/CASE24314.

Clinical and molecular features of patients with IDH1 wild-type primary glioblastoma presenting unexpected short-term survival after gross total resection.

BACKGROUND: This study investigated the factors influencing short-term survivors (STS) after gross total resection (GTR) in patients with IDH1 wild-type primary glioblastoma. METHODS: We analyzed five independent cohorts who underwent GTR, including 83 patients from Kitasato University (K-cohort), and four validation cohorts of 148 patients from co-investigators (V-cohort), 66 patients from the Kansai Molecular Diagnosis Network for the Central Nervous System tumors, 109 patients from the Cancer Genome Atlas, and 40 patients from the Glioma Longitudinal AnalySiS. The study defined STS as those who had an overall survival ≤ 12 months after GTR with subsequent radiation therapy, and concurrent and adjuvant temozolomide (TMZ). RESULTS: The study included 446 patients with glioblastoma. All cohorts experienced unexpected STS after GTR, with a range of 15.0-23.9% of the cases. Molecular profiling revealed no significant difference in major genetic alterations between the STS and non-STS groups, including MGMT, TERT, EGFR, PTEN, and CDKN2A. Clinically, the STS group had a higher incidence of non-local recurrence early in their treatment course, with 60.0% of non-local recurrence in the K-cohort and 43.5% in the V-cohort. CONCLUSIONS: The study revealed that unexpected STS after GTR in patients with glioblastoma is not uncommon and such tumors tend to present early non-local recurrence. Interestingly, we did not find any significant genetic alterations in the STS group, indicating that such major alterations are characteristics of GB rather than being reliable predictors for recurrence patterns or development of unexpected STS.

Excessive Heat Generation by Power-Driven Craniotomy Tools: A Possible Cause of Autologous Bone Flap Resorption Observed in an Ex Vivo Simulation.

BACKGROUND: Bone flap resorption is an issue after autologous cranioplasty. Critical temperatures above 50°C generated by power-driven craniotomy tools may lead to thermal osteonecrosis, a possible factor in resorption. This ex vivo study examined whether the tools produced excessive heat resulting in bone flap resorption. METHODS: Using swine scapulae maintained at body temperature, burr holes, straight and curved cuts, and wire-pass holes were made with power-driven craniotomy tools. Drilling was at the conventional feed rate (FR) plus irrigation (FR-I+), at a high FR plus irrigation (hFR-I+), and at high FR without irrigation (hFR-I-). The temperature in each trial was recorded by an infrared thermographic camera. RESULTS: With FR-I+, the maximum temperature at the burr holes, the cuts, and the wire-pass holes was 69.0°C, 56.7°C, and 46.2°C, respectively. With hFR-I+, these temperatures were 53.1°C, 52.1°C, and 46.0°C, with hFR-I- they were 56.0°C, 66.5°C, and 50.0°C; hFR-I- burr hole- and cutting procedures resulted in the highest incidence of bone temperatures above 50°C followed by FR-I+, and hFR-I+. At the site of wire-pass holes, only hFR-I- drilling produced this temperature. CONCLUSIONS: Except during prolonged procedures in thick bones, most drilling with irrigation did not reach the critical temperature. Drilling without irrigation risked generating the critical temperature. Knowing those characteristics may be a help to perform craniotomy with less thermal bone damage.

Trans-Sylvian and Transanterior Ascending Ramus Approach for Insular Gliomas at Zone I: 2-Dimensional Operative Video.

Insular gliomas present significant challenges because of their deep-seated location and proximity to critical structures, including Sylvian veins, middle cerebral arteries, lenticulostriate arteries,1 long insular arteries,2 and functional cortices.3-6 The Berger-Sanai classification categorizes them into 4 zones (I-IV), providing a framework for understanding insular gliomas.7 The key factors for successful insular glioma removal are achieving the greatest insular exposure and surgical freedom.3 Given that the trans-Sylvian approach8,9 creates a narrow, linear surgical window,3 regardless of the zones, various surgical options have been employed, such as the trans-Sylvian approach with bridging vein cuts and the transcortical approach through functionally silent cortex.3,7,9-13 Dissecting sulci in glioma surgeries has proven beneficial.14-16 In this video publication, we dissected the anterior ascending ramus (AAR) and the Sylvian fissure, creating a triangular window instead of a linear one. A 74-year-old right-handed woman with a zone I insular glioma underwent a trans-Sylvian and trans-AAR approach, achieving total resection of the tumor without new neurological deficits. This approach provided maximum exposure of the insular region, offering a wide view from the anterior limiting sulcus to the anterior half of the superior limiting sulcus of the insula. The histological diagnosis revealed a rare adult pilocytic astrocytoma at the insula, documented in only one case report.17 The AAR,4 defined as a lateral sulcus (Sylvian fissure) branch,18 is present in 98.89% of hemispheres19; therefore, this surgical approach demonstrates broad applicability to zone I insular tumors. The patient provided consent for the procedure and the publication of her image under institutional review board approval (G23-08).

Combination of neuroendoscopic hematoma evacuation and endovascular coil embolization for a ruptured anterior choroidal artery aneurysm in patients with moyamoya disease: illustrative cases.

BACKGROUND: The treatment strategy for hemorrhagic moyamoya disease (MMD) due to a ruptured aneurysm at the distal portion of the anterior choroidal artery remains controversial. The authors successfully treated the ruptured aneurysm with neuroendoscopic hematoma evacuation, followed by endovascular coil embolization. OBSERVATIONS: The authors encountered two patients with massive hemorrhagic MMD whose MMD had already been diagnosed and who had a periventricular anastomosis due to a ruptured aneurysm of the distal portion of the anterior choroidal artery involving the periventricular anastomosis. In both cases, neuroendoscopic hematoma evacuation was performed for hemorrhagic MMD in the acute phase, followed by endovascular coil embolization of the ruptured aneurysm in the chronic phase. In both endovascular treatments, the patient's condition was stabilized by hematoma evacuation, allowing a detailed preoperative evaluation of the anatomical findings of the vessel and functional findings of intraoperative neurophysiological monitoring using continuous monitoring of motor evoked potentials to preserve motor function. LESSONS: Combination therapy can be useful for hemorrhagic MMD in patients with diagnosed MMD with a periventricular anastomosis. Additionally, a preoperative understanding of the vascular construction and intraoperative neurophysiological monitoring will aid in the successful coil embolization of aneurysms at the distal portion of the anterior choroidal artery with hemorrhagic MMD.

Distant recurrence in the cerebellar dentate nucleus through the dentato-rubro-thalamo-cortical pathway in supratentorial glioma cases.

BACKGROUND: Distant recurrence can occur by infiltration along white matter tracts or dissemination through the cerebrospinal fluid (CSF). This study aimed to clarify the clinical features and mechanisms of recurrence in the dentate nucleus (DN) in patients with supratentorial gliomas. Based on the review of our patients, we verified the hypothesis that distant DN recurrence from a supratentorial lesion occurs through the dentato-rubro-thalamo-cortical (DRTC) pathway. METHODS: A total of 380 patients with supratentorial astrocytoma, isocitrate dehydrogenase (IDH)-mutant (astrocytoma), oligodendroglioma, IDH mutant and 1p/19q-codeleted (oligodendroglioma), glioblastoma, IDH-wild type (GB), and thalamic diffuse midline glioma, H3 K27-altered (DMG), who underwent tumor resection at our department from 2009 to 2022 were included in this study. Recurrence patterns were reviewed. Additionally, clinical features and magnetic resonance imaging findings before treatment, at the appearance of an abnormal signal, and at further progression due to delayed diagnosis or after salvage treatment of cases with recurrence in the DN were reviewed. RESULTS: Of the 380 patients, 8 (2.1%) had first recurrence in the DN, 3 were asymptomatic when abnormal signals appeared, and 5 were diagnosed within one month after the onset of symptoms. Recurrence in the DN developed in 8 (7.4%) of 108 cases of astrocytoma, GB, or DMG at the frontal lobe or thalamus, whereas no other histological types or sites showed recurrence in the DN. At the time of the appearance of abnormal signals, a diffuse lesion developed at the hilus of the DN. The patterns of further progression showed that the lesions extended to the superior cerebellar peduncle, tectum, tegmentum, red nucleus, thalamus, and internal capsule along the DRTC pathway. CONCLUSION: Distant recurrence along the DRTC pathway is not rare in astrocytomas, GB, or DMG at the frontal lobe or thalamus. Recurrence in the DN developed as a result of the infiltration of tumor cells through the DRTC pathway, not dissemination through the CSF.

Frontotemporal craniotomy with skin incision along the superior temporal line outside the hairline in bald male patients with temporal gliomas.

A head skin incision is inevitable in neurosurgical procedures and is usually concealed within the hairline. Androgenetic alopecia (AGA) is a progressive hair loss disorder or baldness highly prevalent in men. Therefore, if bald male patients require neurosurgical procedures, skin incisions cannot be concealed, but this subject is yet to be discussed in the literature. This study presents a frontotemporal craniotomy using a skin incision along the superior temporal line, ignoring the hairline in bald male patients. Thirty-three patients with temporal gliomas underwent surgical removal between 2015 and 2022. They were divided into three groups: bald male patients with skin incisions not concealed in the hairline (minimum group, n = 13), bald and non-bald male patients with skin incisions concealed in the hairline (male group, n = 11), and female patients with skin incisions concealed in the hairline (female group, n = 9). In the minimum group, patients had no complaints regarding the incision scar. Cosmetic outcome was excellent, and no cases showed surgical site infection or peripheral facial nerve palsy. Compared with the male and female groups, the minimum group had the shortest skin incision length; however, the craniotomy size and extent of resection were similar. Skin incision for frontotemporal craniotomy cannot be hidden in bald male patients, and the preferred location for the incision is unknown. The skin incision along the superior temporal line is a cosmetically favorable, feasible, and safe procedure.

Angiographic evaluation of the distance from the top of the jugular bulb to the inferior petrosal sinus-internal jugular vein junction: simple classification and identification method for the orifice of the non-visualized inferior petrosal sinus during neuroendovascular surgery.

BACKGROUND: The inferior petrosal sinus (IPS) is the transvenous access route for neurointerventional surgery that is occasionally undetectable on digital subtraction angiography (DSA) because of blockage by a clot or collapse. This study was aimed at analyzing the distance from the jugular bulb (JB) to the IPS-internal jugular vein (IJV) junction and proposing a new anatomical classification system for the IPS-IJV junction to identify the non-visualized IPS orifice. METHODS: DSA of 708 IPSs of 375 consecutive patients were retrospectively investigated to calculate the distance from the top of the JB to the IPS-IJV junction, and a simple classification system based on this distance was proposed. RESULTS: The median distance from the top of the JB to the IPS-IJV junction was 20.8 ± 14.7 mm. Based on the lower (10.9 mm) and upper (31.1 mm) quartiles, IPS-IJV junction variants were: type I, 0-10 mm (22.3%); type II, 11-30 mm (45.8%); type III, > 31 mm (23.9%); and type IV, no connection to the IJV (8.0%). Bilateral distances showed a positive interrelationship, with a correlation coefficient of 0.86. The bilateral symmetry type (visualized IPSs bilaterally) according to our classification occurred in 267 of 300 (89.0%) patients. CONCLUSIONS: In this study, the IPS-IJV junction was located far from the JB (types II and III), with a higher probability (69.6%). This distance and the four-type classification demonstrated high degrees of homology with the contralateral side. These results would be useful for identifying the non-visualized IPS orifice.

Bilateral Trans-Sulcal and Interhemispheric Approaches for Butterfly Glioblastoma: 2-Dimensional Operative Video.

Butterfly glioblastoma (bGB) poses significant surgical challenges, yet recent findings have highlighted the potential of surgical decompression in extending patient survival.1-10 The selection of a surgical strategy for bGB varies across studies. Generally, the side with a larger tumor volume is a preferred approach route, and the nondominant hemisphere is preferred when both tumors are similar in size. The contralateral tumor is removed via the resection cavity of the ipsilateral side,11 with successful utilization of endoscopic-assisted techniques.8 In the case of deep-seated bGB covered with a thick intact brain, accessing the tumor requires creating an invasive corridor, therefore minimizing the damage to the intact brain is ideal. A man in his 70s presented the new-onset seizure. Preoperatively, the patient exhibited a Karnofsky performance status of 50% without any motor deficits, and magnetic resonance imaging demonstrated a deep-seated anterior bGB with a larger tumor volume on the left dominant side. Imaging showed the tumor located just beneath the bilateral superior frontal sulci. Therefore we used these sulci to access the tumor with the minimum cut of the intact brain while preserving the frontal aslant tracts and used bilateral interhemispheric approaches to protect the cingulate bundles. We conducted the same technique for another deep-seated anterior bGB case, both resulting in postoperative Karnofsky performance status improvements (Video 1). Tailoring the surgical approach to the unique characteristics of each bGB case is important. The patients consented to the procedure and the publication of their images.

Distinct patterns of copy number alterations may predict poor outcome in central nervous system germ cell tumors.

We have previously reported that 12p gain may predict the presence of malignant components and poor prognosis for CNS germ cell tumor (GCT). Recently, 3p25.3 gain was identified as an independent predictor of poor prognosis for testicular GCT. Eighty-one CNS GCTs were analyzed. Copy number was calculated using methylation arrays. Five cases (6.2%) showed 3p25.3 gain, but only among the 40 non-germinomatous GCTs (NGGCTs) (5/40, 12.5%; p = 0.03). Among NGGCTs, those with a yolk sac tumor component showed a significantly higher frequency of 3p25.3 gain (18.2%) than those without (1.5%; p = 0.048). NGGCTs with gain showed significantly shorter progression-free survival (PFS) than those without (p = 0.047). The 3p25.3 gain and 12p gain were independent from each other. The combination of 3p25.3 gain and/or 12p gain was more frequent among NGGCTs with malignant components (69%) than among those without (29%; p = 0.02). Germinomas containing a higher number of copy number alterations showed shorter PFS than those with fewer (p = 0.03). Taken together, a finding of 3p25.3 gain may be a copy number alteration specific to NGGCTs and in combination with 12p gain could serve as a marker of negative prognosis or treatment resistance. Germinoma with frequent chromosomal instability may constitute an unfavorable subgroup.

[Glioblastoma, IDH-Wildtype].

The 5th edition of the WHO Classification of Central Nervous System Tumours(WHO2021)emphasizes the importance of molecular classification. A significant update was that glioblastoma IDH-mutant from WHO2016 was renamed and classified as astrocytoma IDH-mutant WHO grade 4 in WHO2021. This review describes the current updates to the glioblastoma classification, and discusses the essential knowledge regarding daily practice, especially for young neurosurgeons.

Frontotemporal Craniotomy for Clipping of Unruptured Aneurysm Using a Diamond-Coated Thread Wire Saw and Reconstruction Using Calcium Phosphate Cement without Metal Fixation.

Metal fixation systems for cranial bone flaps cut by a drill are convenient devices for cranioplasty, but cause several complications. We use modified craniotomy using a fine diamond-coated threadwire saw (diamond T-saw) to reduce the bone defect, and osteoplasty calcium phosphate cement without metal fixation. We report our outcomes and tips of this method. A total of 78 consecutive patients underwent elective frontotemporal craniotomy for clipping of unruptured intracranial aneurysms between 2015 and 2019. The follow-up periods ranged from 13 to 66 months. The bone fixation state was evaluated by bone computed tomography (CT) and three-dimensional CT (3D-CT). The diamond T-saw could minimize the bone defect. Only one wound infection occurred within 1 week postoperatively, and no late infection. No pain, palpable/cosmetically noticeable displacement of the bone flap, fluid accumulations, or other complications were observed. The condition of bone fixation and the cosmetic efficacy were thoroughly satisfactory for all patients, and bone CT and 3D-CT demonstrated that good bone fusion. No complication typical of metal fixation occurred. Our method is technically easy and safety, and achieved good mid-term bone flap fixation in the mid-term course, so has potential for bone fixation without the use of metal plates.

Salvage craniospinal irradiation for recurrent intracranial germinoma: a single institution analysis.

This study investigated the effectiveness and safety of low-dose salvage craniospinal irradiation (CSI) for recurrent germinoma. We retrospectively reviewed long-term tumor control and late adverse effects in 15 recurrent germinoma patients treated at our hospital between 1983 and 2019. Following the first recurrence of germinoma, seven were treated with 24-30 Gy of salvage CSI, three underwent non-CSI, and five were treated with only chemotherapy. CSI achieved a significantly better recurrence-free survival rate after the first recurrence compared to other strategies (100% vs 33%, p < 0.001: log-rank test). To evaluate the safety of salvage CSI, we assessed the outcomes at the final follow-up of seven patients who received salvage CSI at first recurrence and three patients who received salvage CSI at second recurrence. The median follow-up period was 220 months after initial treatment. Five patients who received 40-50 Gy of radiation therapy or underwent multiple radiation therapy before salvage CSI were classified into Group A, whereas five patients treated with platinum-based chemotherapy and 24-32 Gy of radiation therapy to the primary site, whole ventricle, or whole brain were classified into Group B. In Group A, one had endocrine dysfunction and the other had visual dysfunction. None were socially independent. Meanwhile, in Group B, no endocrine or visual dysfunction was found, and three patients were socially independent. Salvage CSI achieved excellent tumor control in recurrent germinoma and was safe in patients initially treated with low-dose radiation therapy and chemotherapy.

Scratching and Stretching the Shrunken Cranial Dura for Primary Closure.

BACKGROUND: At craniotomy, the dura shrinks due to the drying effect of illumination and air exposure, rendering its primary closure difficult. When the opening is narrow, it can be patched with autologous grafts. However, tissue harvesting and meticulous suturing take time. As the cost-effectiveness of using dural substitutes is poor, we developed a new technique that involves dural scratching for the primary closure of dural openings. METHODS: We applied our technique because in 53 adults who underwent supratentorial craniotomy we encountered difficulties with the primary closure of a dural opening 5 mm or less in width. With a scalpel, we placed several fine scratches parallel to the edge of the opening on the surface of the dura, taking care not to perforate the deep layer. This relieved dural tension and the tissue was stretched enough to permit closing with sutures. RESULTS: Our technique achieved primary dural closure in 46 of 53 patients (87%) who primarily had undergone narrow supratentorial craniotomies. The other 7 additionally required small autologous grafts to patch narrow residual openings at the intersection of the durotomy. There were no procedure-related complications such as cerebrospinal fluid leakage and persistent headache due to tension of the closed dura. CONCLUSIONS: Dural scratching is simple, safe, requires no special instrumentation, facilitates primary closure of the shrunken dura by stretching, and reduces the need for patch grafting.