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OBJECTIVE Aneurysms that arise on the medial surface of the paraclinoid segment of the internal carotid artery (ICA) are surgically challenging. The contralateral interoptic trajectory, which uses the space between the optic nerves, can partially expose the medial surface of the paraclinoid ICA. In this study, the authors quantitatively measure the area of the medial ICA accessible through the interoptic triangle and propose a potential patient-selection algorithm that is based on preoperative measurements on angiographic imaging. METHODS The contralateral interoptic trajectory was studied on 10 sides of 5 cadaveric heads, through which the medial paraclinoid ICA was identified. The falciform ligament medial to the contralateral optic canal was incised, the contralateral optic nerve was gently elevated, and the medial surface of the paraclinoid ICA was inspected via different viewing angles to obtain maximal exposure. The accessible area on the carotid artery was outlined. The distance from the distal dural ring (DDR) to the proximal and distal borders of this accessible area was measured. The superior and inferior borders were measured using the clockface method relative to a vertical line on the coronal plane. To validate these parameters, preoperative measurements and intraoperative findings were reviewed in 8 clinical cases. RESULTS In the sagittal plane, the mean (SD) distances from the DDR to the proximal and distal ends of the accessible area on the paraclinoid ICA were 2.5 (1.52) mm and 8.4 (2.32) mm, respectively. In the coronal plane, the mean (SD) angles of the superior and inferior ends of the accessible area relative to a vertical line were 21.7° (14.84°) and 130.9° (12.75°), respectively. Six (75%) of 8 clinical cases were consistent with the proposed patient-selection algorithm. CONCLUSIONS The contralateral interoptic approach is a feasible route to access aneurysms that arise from the medial paraclinoid ICA. An aneurysm can be safely clipped via the contralateral interoptic trajectory if 1) both proximal and distal borders of the aneurysm neck are 2.5–8.4 mm distal to the DDR, and 2) at least one border of the aneurysm neck on the coronal clockface is 21.7°–130.9° medial to the vertical line.

OBJECTIVEThe controversy continues over the clinical utility of preoperative embolization for reducing tumor vascularity of intracranial meningiomas prior to resection. Previous studies comparing embolization and nonembolization patients have not controlled for detailed tumor parameters before assessing outcomes.METHODSThe authors reviewed the cases of all patients who underwent resection of a WHO grade I intracranial meningioma at their institution from 2008 to 2016. Propensity score matching was used to generate embolization and nonembolization cohorts of 52 patients each, and a retrospective review of clinical and radiological outcomes was performed.RESULTSIn total, 52 consecutive patients who underwent embolization (mean follow-up 34.8 ± 31.5 months) were compared to 52 patients who did not undergo embolization (mean follow-up 32.8 ± 28.7 months; p = 0.63). Variables controlled for included patient age (p = 0.82), tumor laterality (p > 0.99), tumor location (p > 0.99), tumor diameter (p = 0.07), tumor invasion into a major dural sinus (p > 0.99), and tumor encasement around the internal carotid artery or middle cerebral artery (p > 0.99). The embolization and nonembolization cohorts did not differ in terms of estimated blood loss during surgery (660.4 ± 637.1 ml vs 509.2 ± 422.0 ml; p = 0.17), Simpson grade IV resection (32.7% vs 25.0%; p = 0.39), perioperative procedural complications (26.9% vs 19.2%; p = 0.35), development of permanent new neurological deficits (5.8% vs 7.7%; p = 0.70), or favorable modified Rankin Scale (mRS) score (a score of 0–2) at last follow-up (96.0% vs 92.3%; p = 0.43), respectively. When comparing the final mRS score to the preoperative mRS score, patients in the embolization group were more likely than patients in the nonembolization group to have an improvement in mRS score (50.0% vs 28.8%; p = 0.03).CONCLUSIONSAfter controlling for patient age, tumor size, tumor laterality, tumor location, tumor invasion into a major dural sinus, and tumor encasement of the internal carotid artery or middle cerebral artery, preoperative meningioma embolization intended to decrease tumor vascularity did not improve the surgical outcomes of patients with WHO grade I intracranial meningiomas, but it did lead to a greater chance of clinical improvement compared to patients not treated with embolization.

Background Surgical exposure of the V1 segment of the vertebral artery (V1-VA) at the lower neck may be necessary to address intravascular (atherosclerotic) and extravascular (external compression by neoplastic or degenerative) pathologies. The adjacent anatomy at the lower cervical region is complex and relatively unfamiliar to neurosurgeons compared to that of upper cervical levels. High-quality cadaveric images simulating the surgical approach to V1-VA are important for learning the relevant anatomy. Objective To provide a brief stepwise depiction of the exposure of the V1-VA using a cadaveric surgical simulation. Methods A cadaveric surgical simulation was performed on the left side to expose the V1-VA using the retrojugular and interjugular carotid approaches. The important adjacent anatomic structures en route to the V1-VA were identified. Results A stepwise photographic demonstration of the surgical exposure of the V1-VA is provided. Conclusion Exposure of the V1-VA can be challenging and requires a clear anatomic understanding of the relevant anatomy. The present work attempts to facilitate this objective.

Background No longitudinal, long-term, follow-up studies have explored the association between presence and severity of variations in extracranial venous anatomy, and clinical outcomes in patients with multiple sclerosis (MS). Objective This prospective 5-year follow-up study assessed the relationship of variations in extracranial venous anatomy, indicative of chronic cerebrospinal venous insufficiency (CCSVI) on Doppler sonography, according to the International Society for Neurovascular Disease (ISNVD) proposed consensus criteria, with clinical outcomes and disease progression in MS patients. Methods 90 MS patients (52 relapsing-remitting, RRMS and 38 secondary-progressive, SPMS) and 38 age- and sex-matched HIs were prospectively followed for 5.5 years. Extracranial and transcranial Doppler-based venous hemodynamic assessment was conducted at baseline and follow-up to determine the extent of variations in extracranial venous anatomy. Change in Expanded Disability Status Scale (∆EDSS), development of disability progression (DP) and annualized relapse rate (ARR) were assessed. Results No significant differences were observed in MS patients, based on their presence of variations in extracranial venous anatomy at baseline or at the follow-up, in ∆EDSS, development of DP or ARR. While more MS patients had ISNVD CCSVI criteria fulfilled at baseline compared to HIs (58% vs. 37%, p = 0.03), no differences were found at the 5-year follow-up (61% vs. 56%, p = 0.486). Discussion This is the longest follow-up study assessing the longitudinal relationship between the presence of variations in extracranial venous anatomy and clinical outcomes in MS patients. Conclusion: The presence of variations in extracranial venous anatomy does not influence clinical outcomes over the 5-year follow-up in MS patients. Electronic supplementary material The online version of this article (10.1186/s12883-019-1350-2) contains supplementary material, which is available to authorized users.

OBJECTIVEAccess to the ventrolateral pontomesencephalic area may be required for resecting cavernous malformations, performing revascularization of the upper posterior circulation, and treating vascular lesions such as aneurysms. However, such access is challenging because of nearby eloquent structures. Commonly used corridors to this surgical area include the optico-carotid, supracarotid, and carotid-oculomotor triangles. However, the window lateral to the oculomotor nerve can also be used and has not been studied. The authors describe the anatomical window formed between the oculomotor nerve and the medial tentorial edge (the oculomotor-tentorial triangle [OTT]) to the ventrolateral pontomesencephalic area, and assess techniques to expand it.METHODSFour cadaveric heads (8 sides) underwent orbitozygomatic craniotomy. The OTT was exposed via a pretemporal approach. The contents of the OTT were determined and their anatomical features were recorded. Also, dimensions of the brainstem surface exposed lateral and inferior to the oculomotor nerve were measured. Measurements were repeated after completing a transcavernous approach (TcA), and after resection of temporal lobe uncus (UnR).RESULTSThe s1 segment and proximal s2 segment of the superior cerebellar artery (SCA) and P2A segment of the posterior cerebral artery (PCA) were the main contents of the OTT, with average exposed lengths of 6.4 ± 1.3 mm and 5.5 ± 1.6 mm for the SCA and PCA, respectively. The exposed length of the SCA increased to 9.6 ± 2.7 mm after TcA (p = 0.002), and reached 11.6 ± 2.4 mm following UnR (p = 0.004). The exposed PCA length increased to 6.2 ± 1.6 mm after TcA (p = 0.04), and reached 10.4 ± 1.8 mm following UnR (p < 0.001). The brainstem surface was exposed 7.1 ± 0.5 mm inferior and 5.6 ± 0.9 mm lateral to the oculomotor nerve initially. The exposure inferior to the oculomotor nerve increased to 9.3 ± 1.7 mm after TcA (p = 0.003), and to 9.9 ± 2.5 mm after UnR (p = 0.21). The exposure lateral to the oculomotor nerve increased to 8.0 ± 1.7 mm after TcA (p = 0.001), and to 10.4 ± 2.4 mm after UnR (p = 0.002).CONCLUSIONSThe OTT is an anatomical window that provides generous access to the upper ventrolateral pontomesencephalic area, s1- and s2-SCA, and P2A-PCA. This window may be efficiently used to address various pathologies in the region and is considerably expandable by TcA and/or UnR.

Background: The cognitive performance in multiple sclerosis (MS) patients declines with aging, longer disease duration, and possibly cardiovascular comorbidities. Objectives: We investigated whether lower total cerebral arterial blood flow (CABF) measured at the level of the carotid and vertebral arteries may contribute to worse cognitive performance in 132 MS patients and 47 healthy controls. Methods: Total CABF was evaluated with extracranial Doppler, whereas structural T2-lesion volume (LV) and gray matter volume (GMV) were measured on 3T MRI. The cognitive performance was assessed by Symbol Digit Modalities Test (SDMT), Brief Visuospatial Memory Test—Revised (BVMT-R), and California Verbal Learning Test—Second Edition (CVLT-II). Analysis of covariance, partial correlation, and regression models were used to test the differences between study groups and cognition/CABF correlations. False discovery rate (FDR)-corrected (Benjamini–Hochberg) p-values (i.e. q-values) less than 0.05 were considered significant. Results: Association between lower total CABF and the lower cognitive performance was observed only in MS patients ( r = 0.318, q 2 = 0.295, t-statistics = 2.538, standardized β = 0.203, and q = 0.020), but not with memory tests. Cognitively impaired MS patients had lower total CABF compared to cognitively preserved (884.5 vs 1020.2 mL/min, q = 0.008). Conclusion: Cognitively impaired MS patients presented with lower total CABF. Altered CABF may be a result of reduced metabolic rate and might contribute to abnormal cognitive aging in MS.

BACKGROUND Use of the far lateral transcondylar (FL) approach and vagoaccessory triangle is the standard exposure for clipping most posterior inferior cerebellar artery (PICA) aneurysms. However, a distal PICA origin or high-lying vertebrobasilar junction can position the aneurysm beyond the vagoaccessory triangle, making the conventional FL approach inappropriate. OBJECTIVE To demonstrate the utility of the extended retrosigmoid (eRS) approach and a lateral trajectory through the glossopharyngo-cochlear triangle as the surgical corridor for these cases. METHODS High-riding PICA aneurysms treated by microsurgery were retrospectively reviewed, comparing exposure through the eRS and FL approaches. Clinical, surgical, and outcome measures were evaluated. Distances from the aneurysm neck to the internal auditory canal (IAC), jugular foramen, and foramen magnum were measured. RESULTS Six patients with PICA aneurysms underwent clipping using the eRS approach; 5 had high-riding PICA aneurysms based on measurements from preoperative computed tomography angiography (CTA). Mean distances of the aneurysm neck above the foramen magnum, below the IAC, and above the jugular foramen were 27.0 mm, 3.7 mm, and 8.2 mm, respectively. Distances were all significantly lower versus the comparison group of 9 patients with normal or low-riding PICA aneurysms treated using an FL approach (P

OBJECTIVERecently, the prognostic value of the Simpson resection grading scale has been called into question for modern meningioma surgery. In this study, the authors analyzed the relationship between Simpson resection grade and meningioma recurrence in their institutional experience.METHODSThis study is a retrospective review of all patients who underwent resection of a WHO grade I intracranial meningioma at the authors’ institution from 2007 to 2017. Binary logistic regression analysis was used to assess for predictors of Simpson grade IV resection and postoperative neurological morbidity. Cox multivariate analysis was used to assess for predictors of tumor recurrence. Kaplan-Meier analysis and log-rank tests were used to assess and compare recurrence-free survival (RFS) of Simpson resection grades, respectively.RESULTSA total of 492 patients with evaluable data were included for analysis, including 394 women (80.1%) and 98 men (19.9%) with a mean (SD) age of 58.7 (12.8) years. The tumors were most commonly located at the skull base (n = 302; 61.4%) or the convexity/parasagittal region (n = 139; 28.3%). The median (IQR) tumor volume was 6.8 (14.3) cm3. Simpson grade I, II, III, or IV resection was achieved in 105 (21.3%), 155 (31.5%), 52 (10.6%), and 180 (36.6%) patients, respectively. Sixty-three of 180 patients (35.0%) with Simpson grade IV resection were treated with adjuvant radiosurgery. In the multivariate analysis, increasing largest tumor dimension (p < 0.01) and sinus invasion (p < 0.01) predicted Simpson grade IV resection, whereas skull base location predicted neurological morbidity (p = 0.02). Tumor recurrence occurred in 63 patients (12.8%) at a median (IQR) of 36 (40.3) months from surgery. Simpson grade I resection resulted in superior RFS compared with Simpson grade II resection (p = 0.02), Simpson grade III resection (p = 0.01), and Simpson grade IV resection with adjuvant radiosurgery (p = 0.01) or without adjuvant radiosurgery (p < 0.01). In the multivariate analysis, Simpson grade I resection was independently associated with no tumor recurrence (p = 0.04). Simpson grade II and III resections resulted in superior RFS compared with Simpson grade IV resection without adjuvant radiosurgery (p < 0.01) but similar RFS compared with Simpson grade IV resection with adjuvant radiosurgery (p = 0.82). Simpson grade IV resection with adjuvant radiosurgery resulted in superior RFS compared with Simpson grade IV resection without adjuvant radiosurgery (p < 0.01).CONCLUSIONSThe Simpson resection grading scale continues to hold substantial prognostic value in the modern neurosurgical era. When feasible, Simpson grade I resection should remain the goal of intracranial meningioma surgery. Simpson grade IV resection with adjuvant radiosurgery resulted in similar RFS compared with Simpson grade II and III resections.

Background The side-to-side anastomosis is one of the difficult bypass configurations that may be used in various complex cerebral vascular and neoplastic cases. Few pure arterial models exist for practicing this bypass subtype. Objective To provide an optimized side-to-side anastomosis training model using rat common carotid arteries (CCA). Methods Bilateral CCAs were exposed in the neck of 10 anesthetized Sprague-Dawley rats. The arteries were juxtaposed in parallel, using temporary aneurysm clips applied proximally and distally. CCA caliber and the length of CCA juxtaposition were measured. Side-to-side anastomosis was completed and ischemia time was recorded. Unintended complications were recorded for further analysis. Results Anastomosis was completed successfully in all animals. The CCAs were approximated in all animals without any difficulty or undue tension. In 2 rats, death occurred prior to completion of anastomosis, which was attributed to injury to the external jugular vein during vessel exposure. Mean ischemia time was 35 min with an average of 22 sutures done to complete the anastomosis. The average CCA caliber was 1.1 ± 0.2 mm and the arteries could be juxtaposed for an average length of 10.2 ± 1.5 mm. Conclusion Full exposure of the cervical segment of the CCAs enables tension-free approximation of adequate length of the vessel for a side-to-side anastomosis. Avoiding complications during exposure helps in prevention of animal death during the ischemia period.

BACKGROUND Surgical resection of cavernous malformations (CM) in the posterior thalamus, pineal region, and midbrain tectum is technically challenging owing to the presence of adjacent eloquent cortex and critical neurovascular structures. Various supracerebellar infratentorial (SCIT) approaches have been used in the surgical armamentarium targeting lesions in this region, including the median, paramedian, and extreme lateral variants. Surgical view of a posterior thalamic CM from the traditional ipsilateral vantage point may be obscured by occipital lobe and tentorium. OBJECTIVE To describe a novel surgical approach via a contralateral SCIT (cSCIT) trajectory for resecting posterior thalamic CMs. METHODS From 1997 to 2017, 75 patients underwent the SCIT approach for cerebrovascular/oncologic pathology by the senior author. Of these, 30 patients underwent the SCIT approach for CM resection, and 3 patients underwent the cSCIT approach. Historical patient data, radiographic features, surgical technique, and postoperative neurological outcomes were evaluated in each patient. RESULTS All 3 patients presented with symptomatic CMs within the right posterior thalamus with radiographic evidence of hemorrhage. All surgeries were performed in the sitting position. There were no intraoperative complications. Neuroimaging demonstrated complete CM resection in all cases. There were no new or worsening neurological deficits or evidence of rebleeding/recurrence noted postoperatively. CONCLUSION This study establishes the surgical feasibility of a contralateral SCIT approach in resection of symptomatic thalamic CMs It demonstrates the application for this procedure in extending the surgical trajectory superiorly and laterally and maximizing safe resectability of these deep CMs with gravity-assisted brain retraction.

BACKGROUND Surgical resection of cavernous malformations (CM) in the posterior thalamus, pineal region, and midbrain tectum is technically challenging owing to the presence of adjacent eloquent cortex and critical neurovascular structures. Various supracerebellar infratentorial (SCIT) approaches have been used in the surgical armamentarium targeting lesions in this region, including the median, paramedian, and extreme lateral variants. Surgical view of a posterior thalamic CM from the traditional ipsilateral vantage point may be obscured by occipital lobe and tentorium. OBJECTIVE To describe a novel surgical approach via a contralateral SCIT (cSCIT) trajectory for resecting posterior thalamic CMs. METHODS From 1997 to 2017, 75 patients underwent the SCIT approach for cerebrovascular/oncologic pathology by the senior author. Of these, 30 patients underwent the SCIT approach for CM resection, and 3 patients underwent the cSCIT approach. Historical patient data, radiographic features, surgical technique, and postoperative neurological outcomes were evaluated in each patient. RESULTS All 3 patients presented with symptomatic CMs within the right posterior thalamus with radiographic evidence of hemorrhage. All surgeries were performed in the sitting position. There were no intraoperative complications. Neuroimaging demonstrated complete CM resection in all cases. There were no new or worsening neurological deficits or evidence of rebleeding/recurrence noted postoperatively. CONCLUSION This study establishes the surgical feasibility of a contralateral SCIT approach in resection of symptomatic thalamic CMs It demonstrates the application for this procedure in extending the surgical trajectory superiorly and laterally and maximizing safe resectability of these deep CMs with gravity-assisted brain retraction.

In situ bypasses to the anterior inferior cerebellar artery (AICA) are unusual because, with only one artery in the cerebellopontine angle (CPA), no natural intracranial donors parallel its course. In rare cases, the posterior inferior cerebellar artery (PICA) may have the tortuosity or redundancy to be mobilized to the AICA to serve as a donor. This video demonstrates this p3 PICA-to-a3 AICA in situ side-to-side bypass. A 75-yr-old woman presented with ataxia and hemiparesis from a large thrombotic right AICA aneurysm compressing the brainstem. Strategy consisted of bypass, trapping, and brainstem decompression. Written informed consent for surgery was obtained from the patient. A hockey-stick incision was made to harvest the occipital artery as a backup donor, but its diminutive caliber precluded its use. The bypass was performed through an extended retrosigmoid craniotomy. The aneurysm was trapped completely and thrombectomized to relieve the pontine mass effect. Indocyanine green videoangiography confirmed patency of the bypass, retrograde filling of the AICA to supply pontine perforators, and no residual aneurysmal filling. This unusual in situ bypass is possible when redundancy of the AICA and PICA allow their approximation in the CPA. The anastomosis is performed lateral to the lower cranial nerves in a relatively open and superficial plane. The extended retrosigmoid approach provides adequate exposure for both the bypass and aneurysm trapping. In situ AICA-PICA bypass enables anterograde and retrograde AICA revascularization with side-to-side anastomosis. The occipital artery-to-AICA bypass and the V3 vertebral artery-to-AICA interpositional bypass are alternatives when intracranial anatomy is unfavorable for this in situ bypass.1-6 Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Extracranial vertebral artery (VA) atherosclerosis is responsible for 14% to 32% of posterior circulation infarctions.1 In the posterior circulation, narrowing of the VA > 30% is significantly associated with strokes. Subclavian artery (SCA) atherosclerosis can produce subclavian steal. Retrograde VA flow around an occluded SCA decreases blood flow to the posterior circulation and causes vertebrobasilar insufficiency (VBI). Flow augmentation to the posterior circulation can be achieved by VA endarterectomy, arterial stenting, VA-common carotid artery (CCA) transposition, or bypass using an interposition graft.2,3 This video illustrates microsurgical revascularization of the proximal VA with VA-CCA transposition. A 58-yr-old man with a prior stroke and chronic right VA occlusion presented with dysarthria and gait instability. Angiographic evaluation confirmed complete midcervical right VA occlusion and left SCA occlusion proximal to VA origin, with subclavian steal. After obtaining patient consent and a failed attempt at endovascular recanalization of the left SCA, a left VA-CCA end-to-side transposition was performed. Neck dissection exposed the left CCA. The thyrocervical trunk served as a landmark to identify the SCA, which was traced proximally to the VA origin. After proximal occlusion, the VA was transected and "fish-mouthed" for end-to-side anastomosis to CCA. An intraluminal, continuous suture technique was used to sew the back walls of this anastomosis. Postoperative computed tomography angiography confirmed bypass patency. Collateral circulation through the thyrocervical and costocervical trunks likely supplied the left arm, and no cerebral, or limb, ischemic symptoms were noted on follow-up. VA-CCA transposition is an uncommon technique for safe and effective revascularization of symptomatic, medically refractory VBI caused by VA occlusion or, as in this case, SCA occlusion with secondary subclavian steal. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Indocyanine green videoangiography (ICG-VA) is a near-infrared range fluorescent marker used for intraoperative real-time assessment of flow in cerebrovascular surgery. Given its high spatial and temporal resolution, ICG-VA has been widely established as a useful technique to perform a qualitative analysis of the graft patency during revascularization procedures. In addition, this fluorescent modality can also provide valuable qualitative and quantitative information regarding the cerebral blood flow within the bypass graft and in the territories supplied. Digital subtraction angiography (DSA) is considered to be the gold standard diagnostic modality for postoperative bypass graft patency assessment. However, this technique is time and labor intensive and an expensive interventional procedure. In contrast, ICG-VA can be performed intraoperatively with no significant addition to the total operative time and, when used correctly, can accurately show acute occlusion. Such time-sensitive ischemic injury detection is critical for flow reestablishment through direct surgical management. In addition, ICG has an excellent safety profile, with few adverse events reported in the literature. This review outlines the chemical behavior, technical aspects, and clinical implications of this tool as an intraoperative adjunct in revascularization procedures.

Objective: Fluorescence dyes are increasingly used in brain tumor surgeries, and thus the development of simulation models is important for teaching neurosurgery trainees how to perform fluorescence-guided operations. We aimed to create a tumor model for fluorescence-guided surgery in high-grade glioma (HGG). Methods: The tumor model was generated by the following steps: creating a tumor gel with a similar consistency to HGG, selecting fluorophores at optimal concentrations with realistic color, mixing the fluorophores with tumor gel, injecting the gel into fresh pig/sheep brain, and testing resection of the tumor model under a fluorescence microscope. The optimal tumor gel was selected among different combinations of agar and gelatin. The fluorophores included fluorescein, indocyanine green (ICG), europium, chlorin e6 (Ce6), and protoporphyrin IX (PpIX). The tumor model was tested by neurosurgeons and neurosurgery trainees, and a survey was used to assess the validity of the model. In addition, the photobleaching phenomenon was studied to evaluate its influence on fluorescence detection. Results: The best tumor gel formula in terms of consistency and tactile response was created using 100 mL water at 100°C, 0.5 g of agar, and 3 g of gelatin mixed thoroughly for 3 min. An additional 1 g of agar was added when the tumor gel cooled to 50°C. The optimal fluorophore concentration ranges were fluorescein 1.9 × 10−4 to 3.8 × 10−4 mg/mL, ICG 4.9 × 10−3 to 9.8 × 10−3 mg/mL, europium 7.0 × 10−2 to 1.4 × 10−1 mg/mL, Ce6 2.2 × 10−3 to 4.4 × 10−3 mg/mL, and PpIX 1.8 × 10−2 to 3.5 × 10−2 mg/mL. No statistical differences among fluorophores were found for face validity, content validity, and fluorophore preference. Europium, ICG, and fluorescein were shown to be relatively stable during photobleaching experiments, while chlorin e6 and PpIX had lower stability. Conclusions: The model can efficiently highlight the “tumor” with 3 different colors—green, yellow, or infrared green with color overlay. These models showed high face and content validity, although there was no significant difference among the models regarding the degree of simulation and training effectiveness. They are useful educational tools for teaching the key concepts of intra-axial tumor resection techniques, such as subpial dissection and nuances of fluorescence-guided surgery.

BACKGROUND Three-dimensional (3D) printing holds great potential for lateral skull base surgical training; however, studies evaluating the use of 3D-printed models for simulating transtemporal approaches are lacking. OBJECTIVE To develop and evaluate a 3D-printed model that accurately represents the anatomic relationships, surgical corridor, and surgical working angles achieved with increasingly aggressive temporal bone resection in lateral skull base approaches. METHODS Cadaveric temporal bones underwent thin-slice computerized tomography, and key anatomic landmarks were segmented using 3D imaging software. Corresponding 3D-printed temporal bone models were created, and 4 stages of increasingly aggressive transtemporal approaches were performed (40 total approaches). The surgical exposure and working corridor were analyzed quantitatively, and measures of face validity, content validity, and construct validity in a cohort of 14 participants were assessed. RESULTS Stereotactic measurements of the surgical angle of approach to the mid-clivus, residual bone angle, and 3D-scanned infill volume demonstrated comparable changes in both the 3D temporal bone models and cadaveric specimens based on the increasing stages of transtemporal approaches (PANOVA

OBJECTIVEMeningiomas at the falcotentorial junction represent a rare subgroup of complex meningiomas. Debate remains regarding the appropriate treatment strategy for and optimal surgical approach to these tumors, and surgical outcomes have not been well described in the literature. The authors reviewed their single-institution experience in the management, approach selection, and outcomes for patients with falcotentorial meningiomas.METHODSFrom the medical records, the authors identified all patients with falcotentorial meningiomas treated with resection at the Barrow Neurological Institute between January 2007 and October 2017. Perioperative clinical, surgical, and radiographic data were retrospectively collected. For patients who underwent the supracerebellar infratentorial approach, the tentorial angle was defined as the angle between the line joining the nasion with the tuberculum sellae and the tentorium in the midsagittal plane.RESULTSFalcotentorial meningiomas occurred in 0.97% (14/1441) of the patients with meningiomas. Most of the patients (13/14) were female, and the mean patient age was 59.8 ± 11.3 years. Of 17 total surgeries (20 procedures), 11 were single-stage primary surgeries, 3 were two-stage primary surgeries (6 procedures), 2 were reoperations for recurrence, and 1 was a reoperation after surgery had been aborted because of brain edema. Hydrocephalus was present in 5 of 17 cases, 4 of which required additional treatment. Various approaches were used, including the supracerebellar infratentorial (4/17), occipital transtentorial/transfalcine (4/17), anterior interhemispheric transsplenial (3/17), parietal transventricular (1/17), torcular (2/17), and staged supracerebellar infratentorial and occipital transtentorial/transfalcine (3/17) approaches. Of the 17 surgeries, 9 resulted in Simpson grade IV resection, and 3, 1, and 4 surgeries resulted in Simpson grades III, II, and I resection, respectively. The tentorial angle in cases with Simpson grade I resection was significantly smaller than in those with an unfavorable resection grade (43.3° ± 4.67° vs 54.0° ± 3.67°, p = 0.04). Complications occurred in 10 of 22 approaches (17 surgeries) and included visual field defects (6 cases, 2 permanent and 4 transient), hemiparesis (2 cases), hemidysesthesia (1 case), and cerebellar hematoma (1 case).CONCLUSIONSFalcotentorial meningiomas are challenging lesions. A steep tentorial angle is an unfavorable preoperative radiographic factor for achieving maximal resection with the supracerebellar infratentorial approach. Collectively, the study findings show that versatility is required to treat patients with falcotentorial meningiomas and that treatment goals and surgical approach must be individualized to obtain optimal surgical results.

Table S1. Demographics and clinical characteristics in multiple sclerosis patients, according to their disease subtype

Introduction: Brain atrophy measurement in multiple sclerosis (MS) has become an important outcome for determining patients at risk for developing physical and cognitive disability.Areas covered: In this article, we discuss the methodological issues related to using this MRI metric routinely, in a clinical setting. Understanding trajectories of annualized whole brain, gray and white matter, thalamic volume loss, and enlargement of ventricular space in specific MS phenotypes is becoming increasingly important. Evidence is mounting that disease-modifying treatments exert a positive effect on slowing brain atrophy progression in MS.Expert Commentary: While there is a need to translate measurement of brain atrophy to clinical routine at the individual patient level, there are still a number of challenges to be met before this can actually happen, including how to account for biological confounding factors and pseudoatrophy, standardize acquisition and analyses parameters, which can influence the accur...

Lateral medullary arteriovenous malformations (AVMs) are located in the pia on the lateral medullary surface.1 They are supplied by arterial feeders from the V4 segment of the vertebral artery or posterior inferior cerebellar artery. A 64-yr-old man presented with leg spasms and progressively worsening gait. Angiography demonstrated a lateral medullary AVM. Patient consent was obtained for the surgical treatment of this lesion. Owing to its eloquent location, an occlusion in situ was performed without resection.1,2 This technique relies on the interruption of the arterial blood supply and occlusion of the draining vein to occlude the AVM. Intraoperative neurophysiological monitoring of motor and somatosensory evoked potentials was used, and the elimination of arteriovenous shunt flow was confirmed using indocyanine green videoangiography. Occlusion in situ preserves the flow to the delicate brainstem perforators and is safer than resection in selected cases like this one. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Anterior inferior cerebellar artery (AICA) aneurysms are rare lesions with a predisposition for distal location and non-saccular morphology.1,2 These aneurysms are less amenable to clipping and may instead require aneurysm trapping with bypass.3 This video reports a novel bypass for a ruptured, fusiform distal AICA aneurysm. A 51-yr-old woman with newly diagnosed acquired immunodeficiency syndrome presented to the hospital with meningitis and experienced an acute neurological decline while admitted. Neuroimaging revealed a fusiform left a2-AICA aneurysm, thought to be mycotic with diffuse subarachnoid and intraventricular hemorrhage (Hunt-Hess Grade-IV). The occipital artery was harvested as an alternative donor in the myocutaneous flap using a hockey-stick incision. An extended retrosigmoid approach exposed the infectious aneurysm. After aneurysm excision, an a2-AICA-a2-AICA end-to-end reanastomosis was performed in between and deep to the vestibulocochlear nerves superiorly and the glossopharyngeal nerve inferiorly. Indocyanine green videoangiography and postoperative angiogram confirmed bypass patency. Postoperatively, she developed epidural and subdural hematomas due to human immunodeficiency virus-associated coagulopathy and/or increased aspirin sensitivity, requiring reoperation. The patient made a complete recovery at late follow-up. AICA reanastomosis is an elegant intracranial-intracranial bypass for treating distal AICA aneurysms. To our knowledge, this is the first report of AICA reanastomosis in the proximal a2-AICA (lateral pontine) segment. This technique has been reported in the literature for distally located aneurysms (a3-AICA).4 Microanastomosis for more medial AICA aneurysms must be performed deep to the lower cranial nerves. OA to a3-AICA bypass is an alternative in cases where primary reanastomosis is not technically feasible. (Published with permission from Barrow Neurological Institute).

Autonomic nervous system dysfunction has been previously observed in multiple sclerosis (MS) patients. To assess associations between magnetic resonance imaging-detected neuroinflammatory and neurodegenerative pathology and postural venous flow changes indicative of autonomic nervous system function. We used a standardized 3T magnetic resonance imaging protocol to scan 138 patients with MS and 49 healthy controls. Lesion volume and brain volumes were assessed. The cerebral venous flow (CVF) was examined by color-Doppler sonography in supine and upright positions and the difference was calculated as ΔCVF. Based on ΔCVF, subjects were split into absolute or quartile groups. Student’s t test, χ2-test, and analysis of covariance adjusted for age and sex were used accordingly. Benjamini-Hochberg procedure corrected the p-values for multiple comparisons. No differences were found between healthy controls and patients with MS in both supine and upright Doppler-derived CVF, nor in prevalence of abnormal postural venous control. Patients with absolute negative ΔCVF had higher disability scores (p = 0.013), lower gray matter (p = 0.039) and cortical (p = 0.044) volumes. The negative ΔCVF MS group also showed numerically worse bladder/bowel function when compared to the positive ΔCVF (2.3 vs. 1.5, p = 0.052). Similarly, the lowest quartile ΔCVF MS group had higher T1-lesion volumes (p = 0.033), T2-lesion volumes (p = 0.032), and lower deep gray matter (p = 0.043) and thalamus (p = 0.033) volumes when compared to those with higher ΔCVF quartiles. No difference in postural venous outflow between patients with MS and healthy controls was found. However, when the abnormal ΔCVF is present within the MS population, it may be associated with more inflammatory and neurodegenerative pathology. Further studies should explore whether the orthostatic venous changes are an aging or an MS-related phenomenon and if the etiology is due to impaired autonomic nervous system functioning.

BACKGROUND Styloidogenic jugular venous compression syndrome (SJVCS) is a rare cause of idiopathic intracranial hypertension (IIH). OBJECTIVE To elucidate the pathophysiology and the hemodynamics of SJVCS. METHODS We conducted a retrospective review of medical records, clinical images, dynamic venography, and manometry for consecutive patients with SJVCS undergoing microsurgical decompression from April 2009 to October 2017. Patients with IIH with normal venography and manometry findings served as controls. RESULTS Data were analyzed for 10 patients with SJVCS who presented with headaches. Neck flexion exacerbated headaches in 7 patients. Eleven patients with IIH provided control data for normal intracranial venous pressure and styloid process anatomy. Patients with SJVCS had bilateral osseous compression of venous outflow. The styloid processes were significantly longer in patients with SJVCS than in those with IIH (mean [standard deviation (SD)] distance, 31.0 [10.6] vs 19.0 [14.1] mm; P

Objectives: To investigate the factors associated with complementary and alternative medicine (CAM) usage by multiple sclerosis (MS) patients. Design, Setting/Location: Single-center, prospective clinical study at an academic MS center in the northeastern United States. Methods: This study included CAM data from 524 MS patients and 304 healthy controls (HC) enrolled in a prospective study of clinical, neuroimaging, and environmental risk factors in MS at an academic MS Center. Clinical, neuroimaging, and disease-modifying treatment data were obtained. In addition, data on usage of CAM modalities, including acupuncture, aromatherapy, Ayurveda, Chinese herbal medicine, chiropractor, electromagnetic therapy, homeopathy, hypnosis, massage, naturopathy, Qi gong, Reiki, therapeutic touch, and bee stings were collected in an in-person interview. Results: The percentages of HC reporting usage of any CAM (32%) was similar to that in MS patients after diagnosis (30.5%). The usage of any CAM was higher in MS patients after MS diagnosis compared to before MS diagnosis (p

Background and importance Although posterior petrosal approaches are utilized less frequently in many practices today, they continue to provide distinct surgical advantages in carefully selected cases. Here, we report a case of a recurrent cerebellopontine angle (CPA) hemangioblastoma that had failed a prior, more conservative, surgical approach. We provide cadaveric dissections of variations of posterior petrosal approaches to illustrate the advantages of the selected approach. Clinical presentation A 70-yr-old female presented with a growing left CPA hemangioblastoma. The lesion had undergone a prior subtotal resection from a retrosigmoid approach and subsequent adjuvant radiation treatment. The patient had worsening left facial strength, progressive balance difficulty, and absent left auditory function. Preoperative angiogram demonstrated arterial blood supply from the left anterior inferior cerebellar artery (AICA) that was deemed unsafe for embolization due to significant arteriovenous shunting. A posterior petrosal transotic approach was performed in order to optimize the working angle to the anterior brainstem and afford the ability to occlude the vascular supply from AICA prior to surgical resection of the lesion. Conclusion The posterior petrosal transotic approach offers an improved surgical working angle to the anterior brainstem compared to the translabyrinthine approach. This advantage can be particularly important with vascular tumors that receive blood supply anteriorly, as in this case from AICA, and can improve the safety of the resection.

OBJECTIVEExposure of the vertebral artery (VA) between C-1 and C-2 vertebrae (atlantoaxial VA) may be necessary in a variety of pathologies of the craniovertebral junction. Current methods to expose this segment of the VA entail sharp dissection of muscles close to the internal jugular vein and the spinal accessory nerve. The present study assesses the technique of exposing the atlantoaxial VA through a newly defined muscular triangle at the craniovertebral junction.METHODSFive cadaveric heads were prepared for surgical simulation in prone position, turned 30°–45° toward the side of exposure. The atlantoaxial VA was exposed through the subatlantic triangle after reflecting the sternocleidomastoid and splenius capitis muscles inferiorly. The subatlantic triangle was formed by 3 groups of muscles: 1) the levator scapulae and splenius cervicis muscles inferiorly and laterally, 2) the longissimus capitis muscle inferiorly and medially, and 3) the inferior oblique capitis superiorly. The lengths of the VA exposed through the triangle before and after unroofing the C-2 transverse foramen were measured.RESULTSThe subatlantic triangle consistently provided access to the whole length of atlantoaxial VA. The average length of the VA exposed via the subatlantic triangle was 19.5 mm. This average increased to 31.5 mm after the VA was released at the C-2 transverse foramen.CONCLUSIONSThe subatlantic triangle provides a simple and straightforward pathway to expose the atlantoaxial VA. The proposed method may be useful during posterior approaches to the craniovertebral junction should early exposure and control of the atlantoaxial VA become necessary.

BACKGROUND AND IMPORTANCE Trigeminal neuralgia (TN) secondary to a dolichoectatic basilar artery (DBA) is an extremely rare phenomenon. The Kawase approach for macrovascular decompression of this rare pathology been used rarely. CLINICAL PRESENTATION This report describes macrovascular decompression and basilar artery transposition in a 69-yr-old male presenting with progressively worsening left-sided typical TN secondary to a DBA compression. The DBA was successfully decompressed off of the trigeminal nerve via a pterional craniotomy and anterior petrosectomy. The patient had immediate improvement in TN symptoms postoperatively. The patient remained symptom free with nonbothersome facial numbness in the V3 segment at 8-mo postoperative follow-up in clinic. The patient suffered a sixth nerve palsy following surgery, which was later corrected by strabismus surgery. The natural history and epidemiology of TN, results of macrovascular decompression secondary to DBA compression via a traditional suboccipital retrosigmoid approach, and potential advantages of the Kawase approach are also discussed. CONCLUSION The macrovascular decompression strategy succeeded because the compressive force was applied by the DBA to the nerve in a superolateral direction, and the decompressive sling pulled the DBA away from the nerve in an inferomedial direction. The working space and access to the clival dura through the Kawase approach allowed proper corrective pull with a sling.

Confocal Laser Endomicroscopy (CLE) is novel handheld fluorescence imaging technology that has shown promise for rapid intraoperative diagnosis of brain tumor tissue. Currently CLE is capable of image display only and lacks an automatic system to aid the surgeon in diagnostically analyzing the images. The goal of this project was to develop a computer-aided diagnostic approach for CLE imaging of human glioma with feature localization function. Despite the tremendous progress in object detection and image segmentation methods in recent years, most of such methods require large annotated datasets for training. However, manual annotation of thousands of histopathology images by physicians is costly and time consuming. To overcome this problem, we constructed a Weakly-Supervised Learning (WSL)-based model for feature localization that trains on image-level annotations, and then localizes incidences of a class-of-interest in the test image. We developed a novel convolutional neural network for diagnostic features localization from CLE images by employing a novel multiscale activation map that is laterally inhibited and collaterally integrated. To validate our method, we compared the model output to the manual annotation performed by four neurosurgeons on test images. The model achieved 88% mean accuracy and 86% mean intersection over union on intermediate features and 87% mean accuracy and 88% mean intersection over union on restrictive fine features, while outperforming other state of the art methods tested. This system can improve accuracy and efficiency in characterization of CLE images of glioma tissue during surgery, and may augment intraoperative decision-making regarding the tumor margin and improve brain tumor resection.

The "picket fence" technique is a clipping technique used for large, wide-neck complex aneurysms not suitable for conventional clipping.1 With this technique, simple or fenestrated straight clips are stacked side-by-side perpendicular to the neck rather than the conventional parallel placement. In complex aneurysms projecting away from the surgeon, the picket fence technique is impossible. Instead, fenestrated clips are applied in a reverse direction from neck-to-dome, using the blade heels to close the neck. This fenestration tube transmits the bifurcation. This video demonstrates a "reverse picket fence" clipping technique of an incidental, large anterior communicating artery (ACoA) aneurysm in a 52-yr-old woman. Bilaterally adherent A2-anterior cerebral artery (ACA) segments led to abortion of a prior clipping attempt at an outside hospital. After obtaining patient consent, a modified orbitozygomatic craniotomy was performed with gyrus rectus removal. Temporary clips were applied to A1-ACA for freeing the adherent A2-ACA segments from the dome. The aneurysm was clipped using a "reverse picket fence" technique transmitting the A1-A2-A2 bifurcation through the fenestration tube. Bilateral recurrent artery of Heubner was preserved. Indocyanine angiography demonstrated parent vessel patency with complete aneurysm exclusion. Postoperatively, the patient experienced short-term memory loss, which resolved over 6 mo with cognitive rehabilitation. The "reverse picket fence" technique can be considered for large aneurysms directed away from the surgeon, obviating the need for difficult dissection of adherent efferent arteries from aneurysmal sac. Adjusting the heel position of each fenestrated clip in this construct allows the patency of hidden perforators behind the aneurysm to be maintained. Video © Barrow Neurological Institute. Used with permission.

A dolichoectatic intracranial vessel with multiple fusiform aneurysms on the same vessel segment is rare, and usually managed with a bypass with aneurysm trapping. This video demonstrates trapping and a double-barrel superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass to treat two fusiform aneurysms in a left dolichoectatic superior MCA trunk. A 46-year-old man with AIDS presented with aphasia and hemiparesis. IRB approval and patient consent were obtained. Both STA branches (frontal and parietal) were harvested. After widely splitting the sylvian fissure from its proximal portion to the angular gyrus, the two fusiform aneurysms on the superior MCA trunk were identified in the insular recess and the circular sulcus. The outflow artery from each aneurysm was identified and prepared for the bypass. The STA was transected, and both limbs were brought down into the fissure. After trapping the distal aneurysm, an end-to-end anastomosis of the parietal STA branch to the M2 MCA was performed. Thereafter, a second bypass was performed in an end-to-side fashion to an M2 branch from the base of the first aneurysm. The second aneurysm was then trapped. Indocyanine green angiography confirmed the patency of both bypasses. Complete aneurysm occlusion and bypass patency were also confirmed with postoperative angiography. The patient recovered from his pre-operative neurological deficits. This case demonstrates the efficacy of double-barrel STA-MCA bypass in combination with aneurysm trapping in a patient with a complex dolichoectatic superior MCA trunk aneurysm. It also highlights the advantage of using end-to-end anastomosis for deep recipients with limited access.

Surgical resection of insular lesions is challenging due to their proximity to critical neurovascular structures such as the middle cerebral arteries (MCA), Sylvian veins, thalamus, internal capsule (IC), and lenticulostriate arteries. A surgical series using the transsylvian-transinsular approach to treat cerebrovascular pathologies reported ∼5% permanent neurological morbidity.1,2 This case demonstrates the utility of this approach for resecting an insular cavernous malformation (CM).A 25-yr-old female presented with an acute-onset right homonymous hemianopsia. Neuroimaging revealed a large left insular CM, adjacent to the posterior limb of IC. After obtaining IRB approval and patient consent, a left pterional craniotomy with a wide distal Sylvian fissure split was completed. Using neuronavigation, an insular entry point was chosen for corticectomy. The CM was opened with subsequent hematoma evacuation and intracapsular resection technique. Inspection of the cavity revealed remnants anteromedially near the IC, which were removed meticulously, mobilizing the CM away from the IC. Postoperative MRI demonstrated gross total resection of the CM. The patient was discharged home on postoperative day 5 with persistent homonymous hemianopia.This case describes the use of a transsylvian-transinsular approach to access deep lesions with the shortest surgical distance and minimal cortical transgression. A wide Sylvian fissure split exposes the M2 MCA and accesses a safe insular zone, keeping the most eloquent structures deep to the lesion in the surgical corridor. This approach can safely expose vascular pathologies in the insular region without the risk of injury to overlying eloquent frontal and temporal lobes, even in the dominant hemisphere.

Posterior inferior cerebellar artery (PICA) aneurysms account for 3% to 4% of all intracranial aneurysms with an unusually high predilection towards a nonsaccular morphology making microsurgical clipping or endovascular reconstruction of the parent artery difficult. The management of these complicated aneurysms may require revascularization procedures for flow preservation with aneurysm trapping. Recently, there is an increasing inclination towards intracranial-intracranial (IC-IC) bypasses over traditional extracranial donors. This video demonstrates a side-to-side PICA-PICA in situ bypass with trapping of an unruptured incidental right p1-PICA aneurysm. Radiological lesion progression and presence of dysplastic morphological characteristics prompted surgical management. The aneurysm was not amenable to clip reconstruction due to the dysplastic PICA segment and lack of a discernable neck. Institutional Review Board approval and patient consent were sought. With patient in three-quarter-prone position, a right far lateral craniotomy was performed. A left-to-right p3-p3 PICA bypass was completed. The aneurysm was clipped along with proximal PICA at its takeoff from vertebral artery. Indocyanine green videoangiography revealed complete occlusion of aneurysm and proximal PICA and a patent anastomosis with distal right PICA flow. Postoperatively, patient recovered with no new neurological deficits. Dolichoectatic posterior circulation aneurysms are not readily amenable to clip reconstruction. PICA-PICA in situ bypass is an elegant alternative to existing extracranial-intracranial revascularization constructs (occipital artery to PICA).1 There is lower neurological morbidity associated with IC-IC bypass vs PICA reimplantation due to the deep surgical corridor and its proximity to lower cranial nerves. Additionally, in this patient endovascular occlusion posed a higher risk of thrombotic complications and postprocedural cerebellar edema with brainstem compression.2.

OBJECTIVEPathology in the region of the basilar quadrifurcation, anterolateral midbrain, medial tentorium, and interpeduncular and ambient cisterns may be accessed anteriorly via an orbitozygomatic (OZ) craniotomy. In Part 1 of this series, the authors explored the anatomy of the oculomotor-tentorial triangle (OTT). In Part 2, the versatility of the OTT as a surgical workspace for treating vascular pathology is demonstrated.METHODSSixty patients with 61 vascular pathologies treated within or via the OTT from 1998 to 2017 by the senior author were retrospectively reviewed. Patients were grouped together based on pathology/surgical procedure and included 1) aneurysms (n = 19); 2) posterior cerebral artery (PCA)/superior cerebellar artery (SCA) bypasses (n = 24); 3) brainstem cavernous malformations (CMs; n = 14); and 4) tentorial region dural arteriovenous fistulas (dAVFs; n = 4). The majority of patients were approached via an OZ craniotomy, wide sylvian fissure split, and temporal lobe mobilization to widen the OTT.RESULTSAneurysm locations included the P1-P2 junction (n = 7), P2A segment (n = 9), P2/3 (n = 2), and basilar quadrification (n = 1). Aneurysm treatments included clip reconstruction (n = 12), wrapping (n = 3), proximal occlusion (n = 2), and trapping with (n = 1) or without (n = 1) bypass. Pathologies in the bypass group included vertebrobasilar insufficiency (VBI; n = 3) and aneurysms of the basilar trunk (n = 13), basilar apex (n = 4), P1 PCA (n = 2), and s1 SCA (n = 2). Bypasses included M2 middle cerebral artery (MCA)–radial artery graft (RAG)–P2 PCA (n = 8), M2 MCA–saphenous vein graft (SVG)–P2 PCA (n = 3), superficial temporal artery (STA)–P2 PCA (n = 5) or STA–s1 SCA (n = 3), s1 SCA–P2 PCA (n = 1), V3 vertebral artery (VA)–RAG–s1 SCA (n = 1), V3 VA–SVG–P2 PCA (n = 1), anterior temporal artery–s1 SCA (n = 1), and external carotid artery (ECA)–SVG–s1 SCA (n = 1). CMs were located in the midbrain (n = 10) or pontomesencephalic junction (n = 4). dAVFs drained into the tentorial, superior petrosal, cavernous, and sphenobasal sinuses. High rates of aneurysm occlusion (79%), bypass patency (100%), complete CM resection (86%), and dAVF obliteration (100%) were obtained. The overall rate of permanent oculomotor nerve palsy was 8.3%. The majority of patients in the aneurysm (94%), CM (93%), and dAVF (100%) groups had stable or improved modified Rankin Scale scores.CONCLUSIONSThe OTT is an important anatomical triangle and surgical workspace for vascular lesions in and around the crural and ambient cisterns. The OTT can be used to approach a wide variety of vascular pathologies in the region of the basilar quadrifurcation and anterolateral midbrain.

Ophthalmic segment aneurysms (OSAs) are technically challenging lesions with a wide-neck morphology and proximity to the optic nerve. Revascularization and aneurysm trapping are occasionally needed to manage unclippable OSAs. Microsurgical treatment requires anterior clinoidectomy, optic strut drilling, and proximal/distal dural ring dissection for adequate exposure. This video demonstrates a two-stage revascularization and clip reconstruction of an OSA. A 62-yr-old woman was presented, with acute-onset expressive aphasia, right hemineglect, and hemiparesis. Neuroimaging revealed a partially thrombosed giant OSA measuring 2.5 × 2.3 cm2. Patient consent was obtained for bypassing, trapping, and decompressing the aneurysm. A pterional craniotomy was performed and an external carotid artery - radial artery graft - middle cerebral artery bypass was performed. The aneurysm was proximally occluded with a permanent clip on the clinoidal internal carotid artery (ICA). Adherence of the distal supraclinoid ICA to the aneurysm wall did not allow for aneurysm trapping. On postoperative day 8, the patient experienced acute mental status decline due to a frontal intraparenchymal hemorrhage. The aneurysm was trapped in a second surgery to occlude persistent retrograde aneurysm filling. The aneurysm sac was circumferentially dissected with temporary parent artery trapping. The OSA was opened and thrombectomized using an ultrasonic aspirator followed by trapping clip application. Postoperatively, the patient gradually returned to neurological baseline with minimal expressive aphasia. Although OSAs are preferentially treated with flow diversion, giant OSAs with significant mass effect may necessitate microsurgical clipping or trapping with decompressive thrombectomy. This case demonstrates that proximal clip occlusion may not be sufficient for aneurysm thrombosis and rupture prevention. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Most cranial nerve compression syndromes (ie, trigeminal neuralgia and hemifacial spasm) are caused by small arteries impinging on a nerve and are relieved by microvascular decompression. Rarely, cranial nerve compression syndromes can be caused by large artery impingement and can be relieved by macrovascular decompression. When present, this compression often occurs in association with degenerative atherosclerosis in the vertebral arteries (VA) and basilar artery. Conservative treatment is recommended for mild forms, but surgical transposition of the VA away from the root entry zone (REZ) can be considered. This video demonstrates macrovascular decompression of a dolichoectatic VA in a 74-yr-old female with refractory left hemifacial spasm. After obtaining IRB approval, patient consent was sought for the procedure. With the patient in three-quarter-prone position, a far-lateral craniotomy was performed. The dentate ligament was cut to free the VA, and the suprahypoglossal portion of the vagoaccessory triangle was widened. VA compressed the REZ of the facial nerve, but was mobilized anteromedially off the REZ. A muslin sling was wrapped around the VA and its tail brought down to the clival dura, which was punctured with a 19-gauge needle and enlarged with a dissector. The sling was pulled anteromedially to this puncture site and secured to the dura with an aneurysm clip, relieving the REZ of all compression. The patient tolerated the procedure with mild, transient hoarseness and her hemifacial spasm resolved completely. This case demonstrates the macrovascular decompression technique with anteromedial transposition of the vertebrobasilar artery, which can also be used for trigeminal neuralgia.

OBJECTIVE To determine if multiple sclerosis (MS) is associated with lower intraocular pressure (IOP) compared with individuals without MS. METHODS Thirty patients with clinically definite MS were identified and a retrospective chart review was conducted. Each patient with MS underwent IOP recording by a single investigator using kinetic applanation tonometry. Measurement of central corneal thickness (CCT) also was obtained. Similarly, 30 study controls were identified and kinetic applanation tonometry and CCT were recorded. Univariate analysis of covariance was conducted to determine a statistically significant difference between IOP between MS and control groups, controlling for age. RESULTS Analyses were adjusted for age and 2 subjects were excluded because of steroid use. The average IOP in MS group was 12.3 mm Hg (right eye = 12.3 mm Hg, left eye = 12.2 mm Hg) and in the control group was 17 mm Hg (right eye = 16.9 mm Hg, left eye = 17 mm Hg). There was a significant effect of presence of MS on IOP accounting for 53% variability in mean IOP (F(1,55) = 60.7; P < 0.001) when compared with the control group. CONCLUSIONS This study demonstrated that IOP was significantly lower in patients with MS compared with controls. A more in-depth prospective study design is required, along with further investigation of possible etiologies. Identifying the mechanism of decreased IOP in patients with MS might allow development of new-targeted therapies for the treatment of glaucoma.

Background: An impaired cerebrospinal venous drainage was postulated to be a cofactor in the multifactorial path-ogenesis of multiple sclerosis (MS). Chronic cerebrospinal venous insufficiency (CCSVI) is characterized by abnormalities of the main extracranial cerebrospinal venous outflow routes, which can be detected by color Doppler Ultrasound (CDUS) using 5 venous hemodynamic (VH) criteria. Discrepant results between different investigators were reported in the past, therefore the usefulness and applicability of the CCSVI CDUS-based diagnosis in clinical research and practice has been questioned. The reproducibility of proposed criteria for CCSVI detection depends on the blinding, training level, skills of the operator and interpretation of VH criteria. Objectives: To assess agreement between centralized and local reading of CDUS examination for diagnosis of CCSVI in trained Doppler sonologists. Methods: This study was performed in 78 MS patients and 28 age- and sex-matched healthy controls (HCs). Extracranial and transcranial CDUS venous hemodynamic assessment was conducted, according to International Society of Neurovascu-lar Disease (ISNVD) recommended criteria, by a single CCSVI-trained expert sonologist blinded to the subject disease sta-tus. After the local Doppler sonologist performed the investigation, all images and video clips of the CDUS examination were sent to the centralized reading center, where a second blinded reading was performed by two CCSVI-trained expert sonologists. Statistical analyses were performed comparing accuracy of CCSVI diagnosis (≥2 VH criteria) and each of the 5 individual VH criteria using Cohen kappa statistic, along with positive/negative agreement and Odds ratio (OR) with 95% confidence intervals (95% CI). Results: Diagnosis of CCSVI was obtained in 59.7% of local and 64.3% centralized readers (Kappa, 0.67, p

De novo cavernous malformation (CM) formation after radiation therapy for brain tumors is well known, but CM formation adjacent to a radiosurgically treated arteriovenous malformation (AVM) is rare.1 This video demonstrates the microsurgical resection of a de novo CM adjacent to a previously treated high-grade AVM and clipping of a middle cerebral artery (MCA) aneurysm. A 70-yr-old male with history of radiosurgery for AVM presented with aphasia and confusion. Preoperative angiography showed complete occlusion of the AVM. MRI showed multiple cystic lesions suspicious for radiation-induced necrosis and CM. IRB approval and patient consent was obtained. A pterional craniotomy was performed with transsylvian exposure of the insula. The radiated feeding arteries were followed to the occluded AVM nidus. A CM was noted deep to this candelabra of the MCA vessels, which were mobilized to access and resect the CM. A small incision was made in this insular cortex underneath the malformation circumferentially freeing it of adhesions. The sclerotic AVM nidus was circumferentially dissected and removed en bloc. Thorough exploration of the resection cavity revealed no residual CM or AVM nidus. Attention was then turned to the M2-MCA bifurcation aneurysm, which was occluded with a straight clip. Postoperative imaging confirmed complete CM resection. The patient recovered from his aphasia. This case demonstrates the management of a radiation-induced de novo CM following treatment of a high-grade AVM. Radiographic follow-up for radiosurgically treated AVM is needed to rule out long-term complications. Bleeding from a de novo CM mimics bleeding from residual AVM nidus, requiring careful angiographic evaluation.

This video illustrates a contralateral supracerebellar transtentorial (cSCTT) approach for resection of a ruptured thalamic cavernous malformation in a 56-year-old woman with progressive right-sided homonymous hemianopsia. The patient was placed in the sitting position, and a torcular craniotomy was performed for the cSCTT approach. The lesion was resected completely. Postoperatively, the patient had intact motor strength and baseline visual field deficits with moderate right-sided paresthesias. The cSCTT approach maximizes the lateral surgical reach without the cortical transgression seen with alternative transcortical routes.1 Contralaterality is a defining feature, with entry of the neurosurgeon’s instruments from the craniotomy edge of the craniotomy, contralateral to the lesion, allowing access to the lateral aspect of the lesion. The sitting position facilitates gravity-assisted cerebellar retraction and enhances the superior reach of this approach (Used with permission from Barrow Neurological Institute, Phoenix, Arizona).The video can be found here: https://youtu.be/lqB9mu_T8NQ.