METTL3 inhibition reduces N6 -methyladenosine levels and prevents allogeneic CD4+ T-cell responses.

Alloreactive CD4+ T cells play a central role in allograft rejection. However, the post-transcriptional regulation of the effector program in alloreactive CD4+ T cells remains unclear. N6 -methyladenosine (m6 A) RNA modification is involved in various physiological and pathological processes. Herein, we investigated whether m6 A methylation plays a role in the allogeneic T-cell effector program. m6 A levels of CD4+ T cells from spleens, draining lymph nodes and skin allografts were determined in a skin transplantation model. The effects of a METTL3 inhibitor (STM2457) on CD4+ T-cell characteristics including proliferation, cell cycle, cell apoptosis and effector differentiation were determined after stimulation of polyclonal and alloantigen-specific (TEa; CD4+ T cells specific for I-Eα52-68 ) CD4+ T cells with α-CD3/α-CD28 monoclonal antibodies and cognate CB6F1 alloantigen, respectively. We found that graft-infiltrating CD4+ T cells expressed high m6 A levels. Administration of STM2457 reduced m6 A levels, inhibited T-cell proliferation and suppressed effector differentiation of polyclonal CD4+ T cells. Alloreactive TEa cells challenged with 40 µm STM2457 exhibited deficits in T-cell proliferation and T helper type 1 cell differentiation, a cell cycle arrest in the G0 phase and elevated cell apoptosis. Moreover, these impaired T-cell responses were associated with the diminished expression levels of transcription factors Ki-67, c-Myc and T-bet. Therefore, METTL3 inhibition reduces the expression of several key transcriptional factors for the T-cell effector program and suppresses alloreactive CD4+ T-cell effector function and differentiation. Targeting m6 A-related enzymes and molecular machinery in CD4+ T cells represents an attractive therapeutic approach to prevent allograft rejection.

Evaluation of Robotic-Assisted Carotid Artery Stenting in a Virtual Model Using Motion-Based Performance Metrics.

PURPOSE: Robotic-assisted carotid artery stenting (CAS) cases have been demonstrated with promising results. However, no quantitative measurements have been made to compare manual with robotic-assisted CAS. This study aims to quantify surgical performance using tool tip kinematic data and metrics of precision during CAS with manual and robotic control in an ex vivo model. MATERIALS AND METHODS: Transfemoral CAS cases were performed in a high-fidelity endovascular simulator. Participants completed cases with manual and robotic techniques in 2 different carotid anatomies in random order. C-arm angulations, table position, and endovascular devices were standardized. Endovascular tool tip kinematic data were extracted. We calculated the spectral arc length (SPARC), average velocity, and idle time during navigation in the common carotid artery and lesion crossing. Procedural time, fluoroscopy time, movements of the deployed filter wire, precision of stent, and balloon positioning were recorded. Data were analyzed and compared between the 2 modalities. RESULTS: Ten participants performed 40 CAS cases with a procedural success of 100% and 0% residual stenosis. The median procedural time was significantly higher during the robotic-assisted cases (seconds, median [interquartile range, IQR]: 128 [49.5] and 161.5 [62.5], p=0.02). Fluoroscopy time differed significantly between manual and robotic-assisted procedures (seconds, median [IQR]: 81.5 [32] and 98.5 [39.5], p=0.1). Movement of the deployed filter wire did not show significant difference between manual and robotic interventions (mm, median [IQR]: 13 [10.5] and 12.5 [11], p=0.5). The postdilation balloon exceeded the margin of the stent with a median of 2 [1] mm in both groups. Navigation with robotic assistance showed significantly lower SPARC values (-5.78±3.14 and -8.63±3.98, p=0.04) and higher idle time values (8.92±8.71 and 3.47±3.9, p=0.02) than those performed manually. CONCLUSIONS: Robotic-assisted and manual CAS cases are comparable in the precision of stent and balloon positioning. Navigation in the carotid artery is associated with smoother motion and higher idle time values. These findings highlight the accuracy and the motion stabilizing capability of the endovascular robotic system. CLINICAL IMPACT: Robotic assistance in the treatment of peripheral vascular disease is an emerging field and may be a tool for radiation protection and the geographic distribution of endovascular interventions in the future. This preclinical study compares the characteristics of manual and robotic-assisted carotid stenting (CAS). Our results highlight, that robotic-assisted CAS is associated with precise navigation and device positioning, and smoother navigation compared to manual CAS.

Transcarotid access for remote robotic endovascular neurointerventions: a cadaveric proof-of-concept study.

OBJECTIVE: The purpose of this proof-of-concept study was to demonstrate the setup and feasibility of transcarotid access for remote robotic neurointerventions in a cadaveric model. METHODS: The interventional procedures were performed in a fresh-frozen cadaveric model using an endovascular robotic system and a robotic angiography imaging system. A prototype remote, robotic-drive system with an ethernet-based network connectivity and audio-video communication system was used to drive the robotic system remotely. After surgical exposure of the common carotid artery in a cadaveric model, an 8-Fr arterial was inserted and anchored. A telescopic guiding sheath and catheter/microcatheter combination was modified to account for the "workable" length with the CorPath GRX robotic system using transcarotid access. RESULTS: To simulate a carotid stenting procedure, a 0.014-inch wire was advanced robotically to the extracranial internal carotid artery. After confirming the wire position and anatomy by angiography, a self-expandable rapid exchange nitinol stent was loaded into the robotic cassette, advanced, and then deployed robotically across the carotid bifurcation. To simulate an endovascular stroke recanalization procedure, a 0.014-inch wire was advanced into the proximal middle cerebral artery with robotic assistance. A modified 2.95-Fr delivery microcatheter (Velocity, Penumbra Inc.) was loaded into the robotic cassette and positioned. After robotic retraction of the wire, it was switched manually to a mechanical thrombectomy device (Solitaire X, Medtronic). The stentriever was then advanced robotically into the end of the microcatheter. After robotic unfolding and short microcatheter retraction, the microcatheter was manually removed and the stent retriever was extracted using robotic assistance. During intravascular navigation, the device position was guided by 2D angiography and confirmed by 3D cone-beam CT angiography. CONCLUSIONS: In this proof-of-concept cadaver study, the authors demonstrated the setup and technical feasibility of transcarotid access for remote robot-assisted neurointerventions such as carotid artery stenting and mechanical thrombectomy. Using transcarotid access, catheter length modifications were necessary to achieve "working length" compatibility with the current-generation CorPath GRX robotic system. While further improvements in dedicated robotic solutions for neurointerventions and next-generation thrombectomy devices are necessary, the transcarotid approach provides a direct, relatively rapid access route to the brain for delivering remote stroke treatment.

Intraarterial Thrombolysis as Rescue Therapy for Large Vessel Occlusions.

Background and Purpose- Mechanical thrombectomy (MT) devices have led to improved reperfusion and clinical outcomes in acute ischemic stroke patients with emergent large vessel occlusions; however, less than one-third of patients achieve complete reperfusion. Use of intraarterial thrombolysis in the context of MT may provide an opportunity to enhance these results. Here, we evaluate the use of intraarterial rtPA (recombinant tissue-type plasminogen activator) as rescue therapy (RT) after failed MT in the North American Solitaire Stent-Retriever Acute Stroke registry. Methods- The North American Solitaire Stent-Retriever Acute Stroke registry recruited sites within North America to submit data on acute ischemic stroke patients treated with the Solitaire device. After restricting the population of 354 patients to use of RT and anterior emergent large vessel occlusions, we compared patients who were treated with and without intraarterial rtPA after failed MT. Results- A total of 37 and 44 patients was in the intraarterial rtPA RT and the no intraarterial rtPA RT groups, respectively. Revascularization success (modified Thrombolysis in Cerebral Infarction ≥2b) was achieved in more intraarterial rtPA RT patients (61.2% versus 46.6%; P=0.13) with faster times to recanalization (100±85 versus 164±235 minutes; P=0.36) but was not statistically significant. The rate of symptomatic intracranial hemorrhage (13.9% versus 6.8%; P=0.29) and mortality (42.9% versus 44.7%; P=0.87) were similar between the groups. Good functional outcome (modified Rankin Scale score of ≤2) was numerically higher in intraarterial rtPA patients (22.9% versus 18.4%; P=0.64). Further restriction of the RT population to M1 occlusions only and time of onset to groin puncture ≤8 hours, resulted in significantly higher successful revascularization rates in the intraarterial rtPA RT cohort (77.8% versus 38.9%; P=0.02). Conclusions- Intraarterial rtPA as RT demonstrated a similar safety and clinical outcome profile, with higher reperfusion rates achieved in patients with M1 occlusions. Prospective studies are needed to delineate the role of intraarterial thrombolysis in MT.

First Pass Effect: A New Measure for Stroke Thrombectomy Devices.

BACKGROUND AND PURPOSE: In acute ischemic stroke, fast and complete recanalization of the occluded vessel is associated with improved outcomes. We describe a novel measure for newer generation devices: the first pass effect (FPE). FPE is defined as achieving a complete recanalization with a single thrombectomy device pass. METHODS: The North American Solitaire Acute Stroke Registry database was used to identify a FPE subgroup. Their baseline features and clinical outcomes were compared with non-FPE patients. Clinical outcome measures included 90-days modified Rankin Scale score, National Institutes of Health Stroke Scale score, mortality, and symptomatic intracranial hemorrhage. Multivariate analyses were performed to determine whether FPE independently resulted in improved outcomes and to identify predictors of FPE. RESULTS: A total of 354 acute ischemic stroke patients underwent thrombectomy in the North American Solitaire Acute Stroke registry. FPE was achieved in 89 out of 354 (25.1%). More middle cerebral artery occlusions (64% versus 52.5%) and fewer internal carotid artery occlusions (10.1% versus 27.7%) were present in the FPE group. Balloon guide catheters were used more frequently with FPE (64.0% versus 34.7%). Median time to revascularization was significantly faster in the FPE group (median 34 versus 60 minutes; P=0.0003). FPE was an independent predictor of good clinical outcome (modified Rankin Scale score ≤2 was seen in 61.3% in FPE versus 35.3% in non-FPE cohort; P=0.013; odds ratio, 1.7; 95% confidence interval, 1.1-2.7). The independent predictors of achieving FPE were use of balloon guide catheters and non-internal carotid artery terminus occlusion. CONCLUSIONS: The achievement of complete revascularization from a single Solitaire thrombectomy device pass (FPE) is associated with significantly higher rates of good clinical outcome. The FPE is more frequently associated with the use of balloon guide catheters and less likely to be achieved with internal carotid artery terminus occlusion.

Therapeutically Targeting Platelet-Derived Growth Factor-Mediated Signaling Underlying the Pathogenesis of Subarachnoid Hemorrhage-Related Vasospasm.

INTRODUCTION: Vasospasm accounts for a large fraction of the morbidity and mortality burden in patients sustaining subarachnoid hemorrhage (SAH). Platelet-derived growth factor (PDGF)-ß levels rise following SAH and correlate with incidence and severity of vasospasm. METHODS: The literature was reviewed for studies investigating the role of PDGF in the pathogenesis of SAH-related vasospasm and efficacy of pharmacological interventions targeting the PDGF pathway in ameliorating the same and improving clinical outcomes. RESULTS: Release of blood under high pressure into the subarachnoid space activates the complement cascade, which results in release of PDGF. Abluminal contact of blood with cerebral vessels increases their contractile response to PDGF-ß and thrombin, with the latter upregulating PDGF-ß receptors and augmenting effects of PDGF-ß. PDGF-ß figures prominently in the early and late phases of post-SAH vasospasm. PDGF-ß binding to the PDGF receptor-ß results in receptor tyrosine kinase domain activation and consequent stimulation of intracellular signaling pathways, including p38 mitogen-activated protein kinase, phosphatidylinositol-3-kinase, Rho-associated protein kinase, and extracellular regulated kinase 1 and 2. Consequent increases in intracellular calcium and increased expression of genes mediating cellular growth and proliferation mediate PDGF-induced augmentation of vascular smooth muscle cell contractility, hypertrophy, and proliferation. CONCLUSION: Treatments with statins, serine protease inhibitors, and small molecular pathway inhibitors have demonstrated varying degrees of efficacy in prevention of cerebral vasospasm, which is improved with earlier institution.

Predictors of Mortality in Acute Ischemic Stroke Intervention: Analysis of the North American Solitaire Acute Stroke Registry.

BACKGROUND AND PURPOSE: Failure to recanalize predicts mortality in acute ischemic stroke. In the North American Solitaire Acute Stroke registry, we investigated parameters associated with mortality in successfully recanalized patients. METHODS: Logistic regression was used to evaluate baseline characteristics and recanalization parameters for association with 90-day mortality. A multivariable model was developed based on backward selection with retention criteria of P<0.05 from factors with at least marginal significance (P≤0.10), then refit to minimize the number of excluded cases (missing data). RESULTS: Successfully recanalized patients had lower mortality (25.2% [59/234] versus 46.9% [38/81] P<0.001). There was no difference in symptomatic intracranial hemorrhage between patients with successful versus failed recanalization (9% [21/234] versus 14% [11/79]; P=0.205). However, mortality was significantly higher in patients with symptomatic intracranial hemorrhage (72% [23/32] versus 26% [73/281]; P<0.001). Proximal occlusion (internal carotid artery or vertebrobasilar), initial National Institutes of Health Stroke Scale≥18, use of rescue therapy (P<0.05), and 3+ passes (P<0.10) were associated with mortality in recanalized patients. In the multivariate model with good predictive power (c index=0.72), proximal occlusion, initial National Institutes of Health Stroke Scale≥18, and use of rescue therapy remained significant independent predictors of 90-day mortality. CONCLUSIONS: Failure to recanalize and presence of symptomatic intracranial hemorrhage resulted in increased mortality. Despite successful recanalization, proximal occlusion, high National Institutes of Health Stroke Scale, and need for rescue therapy were predictors of mortality.

Update on transient cardiac standstill in cerebrovascular surgery.

Transient cardiac standstill is a complementary procedure used with microsurgery to treat patients with particularly complex aneurysms, such as large or giant cerebral aneurysms. These procedures allow the aneurysms to be decompressed while maintaining a bloodless field and increased surgical exposure. Deep hypothermia combined with circulatory arrest provides cerebroprotection with optimal surgical conditions. However, its disadvantage is the relatively high risk of the procedure, which requires extensive expertise and infrastructure. Thus, its use is typically limited to patients with complex posterior circulation aneurysms. Adenosine-induced transient asystole is an easily applied technique in a variety of clinical situations. Its use requires minimal advanced preparation and no complex logistical coordination with other subspecialties. However, patient-specific dose-response relationships must be determined by exposure, so the relationship may not be known in an emergent situation. Persistent hypotension is a potentially major complication. Rapid ventricular pacing (RVP) has recently been reintroduced into cerebrovascular surgery. It is more predictable than adenosine in response time and, thus, can be used during unanticipated complications, such as aneurysmal rupture. It also induces a shorter period of hypotension compared with adenosine. However, RVP is more invasive and more complex from an anesthesia standpoint. Vascular neurosurgeons should be familiar with these techniques and know their applications and limitations.

Influence of age on clinical and revascularization outcomes in the North American Solitaire Stent-Retriever Acute Stroke Registry.

BACKGROUND AND PURPOSE: The Solitaire With the Intention for Thrombectomy (SWIFT) and thrombectomy revascularization of large vessel occlusions in acute ischemic stroke (TREVO 2) trial results demonstrated improved recanalization rates with mechanical thrombectomy; however, outcomes in the elderly population remain poorly understood. Here, we report the effect of age on clinical and angiographic outcome within the North American Solitaire-FR Stent-Retriever Acute Stroke (NASA) Registry. METHODS: The NASA Registry recruited sites to submit data on consecutive patients treated with Solitaire-FR. Influence of age on clinical and angiographic outcomes was assessed by dichotomizing the cohort into ≤80 and >80 years of age. RESULTS: Three hundred fifty-four patients underwent treatment in 24 centers; 276 patients were ≤80 years and 78 were >80 years of age. Mean age in the ≤80 and >80 cohorts was 62.2±13.2 and 85.2±3.8 years, respectively. Of patients >80 years, 27.3% had a 90-day modified Rankin Score ≤2 versus 45.4% ≤80 years (P=0.02). Mortality was 43.9% and 27.3% in the >80 and ≤80 years cohorts, respectively (P=0.01). There was no significant difference in time to revascularization, revascularization success, or symptomatic intracranial hemorrhage between the groups. Multivariate analysis showed age >80 years as an independent predictor of poor clinical outcome and mortality. Within the >80 cohort, National Institutes of Health Stroke Scale (NIHSS), revascularization rate, rescue therapy use, and symptomatic intracranial hemorrhage were independent predictors of mortality. CONCLUSION: Greater than 80 years of age is predictive of poor clinical outcome and increased mortality compared with younger patients in the NASA registry. However, intravenous tissue-type plasminogen activator use, lower NIHSS, and shorter revascularization time are associated with better outcomes. Further studies are needed to understand the endovascular therapy role in this cohort compared with medical therapy.

North American SOLITAIRE Stent-Retriever Acute Stroke Registry: choice of anesthesia and outcomes.

BACKGROUND AND PURPOSE: Previous work that predated the availability of the safer stent-retriever devices has suggested that general anesthesia (GA) may have a negative impact on outcomes in patients with acute ischemic stroke undergoing endovascular therapy. METHODS: We reviewed demographic, clinical, procedural (GA versus local anesthesia [LA], etc), and site-adjudicated angiographic and clinical outcomes data from consecutive patients treated with the Solitaire FR device in the investigator-initiated North American SOLITAIRE Stent-Retriever Acute Stroke (NASA) Registry. The primary outcomes were 90-day modified Rankin Scale, mortality, and symptomatic intracranial hemorrhage. RESULTS: A total of 281 patients from 18 centers were enrolled. GA was used in 69.8% (196/281) of patients. Baseline demographic and procedural factors were comparable between the LA and GA groups, except the former demonstrated longer time-to-groin puncture (395.4±254 versus 337.4±208 min; P=0.04), lower National Institutes of Health Stroke Scale (NIHSS; 16.2±5.8 versus 18.8±6.9; P=0.002), lower balloon-guide catheter usage (22.4% versus 49.2%; P=0.0001), and longer fluoroscopy times (39.5±33 versus 28±22.8 min; P=0.008). Recanalization (thrombolysis in cerebral infarction ≥2b; 72.94% versus 73.6%; P=0.9) and rate of symptomatic intracranial hemorrhage (7.1% versus 11.2%; P=0.4) were similar but modified Rankin Scale ≤2 was achieved in more LA patients, 52.6% versus 35.6% (odds ratio, 1.4 [1.1-1.8]; P=0.01). In multivariate analysis, hypertension, NIHSS, unsuccessful revascularization, and GA use (odds ratio, 3.3 [1.6-7.1]; P=0.001) were associated with death. When only anterior circulation and elective GA patients were included, there was a persistent difference in good outcomes in favor of LA patients (50.7% versus 35.5%; odds ratio, 1.3 [1.01-1.6]; P=0.04). CONCLUSIONS: The NASA Registry has demonstrated that clinical outcomes and survival are significantly better in patients treated with LA, without increased symptomatic intracranial hemorrhage risk. Future trials should prospectively evaluate the effect of GA on outcomes.

Balloon guide catheter improves revascularization and clinical outcomes with the Solitaire device: analysis of the North American Solitaire Acute Stroke Registry.

BACKGROUND AND PURPOSE: Efficient and timely recanalization is an important goal in acute stroke endovascular therapy. Several studies demonstrated improved recanalization and clinical outcomes with the stent retriever devices compared with the Merci device. The goal of this study was to evaluate the role of the balloon guide catheter (BGC) and recanalization success in a substudy of the North American Solitaire Acute Stroke (NASA) registry. METHODS: The investigator-initiated NASA registry recruited 24 clinical sites within North America to submit demographic, clinical, site-adjudicated angiographic, and clinical outcome data on consecutive patients treated with the Solitaire Flow Restoration device. BGC use was at the discretion of the treating physicians. RESULTS: There were 354 patients included in the NASA registry. BGC data were reported in 338 of 354 patients in this subanalysis, of which 149 (44%) had placement of a BGC. Mean age was 67.3±15.2 years, and median National Institutes of Health Stroke Scale score was 18. Patients with BGC had more hypertension (82.4% versus 72.5%; P=0.05), atrial fibrillation (50.3% versus 32.8%; P=0.001), and were more commonly administered tissue plasminogen activator (51.6% versus 38.8%; P=0.02) compared with patients without BGC. Time from symptom onset to groin puncture and number of passes were similar between the 2 groups. Procedure time was shorter in patients with BGC (120±28.5 versus 161±35.6 minutes; P=0.02), and less adjunctive therapy was used in patients with BGC (20% versus 28.6%; P=0.05). Thrombolysis in cerebral infarction 3 reperfusion scores were higher in patients with BGC (53.7% versus 32.5%; P<0.001). Distal emboli and emboli in new territory were similar between the 2 groups. Discharge National Institutes of Health Stroke Scale score (mean, 12±14.5 versus 17.5±16; P=0.002) and good clinical outcome at 3 months were superior in patients with BGC compared with patients without (51.6% versus 35.8%; P=0.02). Multivariate analysis demonstrated that the use of BGC was an independent predictor of good clinical outcome (odds ratio, 2.5; 95% confidence interval, 1.2-4.9). CONCLUSIONS: Use of a BGC with the Solitaire Flow Restoration device resulted in superior revascularization results, faster procedure times, decreased need for adjunctive therapy, and improved clinical outcome.

Surgical corridor formation by minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach in pineal region tumor surgery: A review of 11 cases.

INTRODUCTION: The pineal region is a hard-to-reach part of the brain. There is no unequivocal opinion on the choice of a surgical approach to the pineal region. The surgical approaches described differ in both trajectory (infra- and supratentorial, interhemispheric) and size of craniotomy. They have advantages and disadvantages. The minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach we have described has all the advantages of the standard supratentorial approach and minimizes its disadvantages, namely, compression and contusion of the occipital lobe. The minimally invasive craniotomy and small surgical corridor facilitate that. METHODS: We describe 11 consecutive patients with various pineal region tumors (7 cases of pineal cysts, 2 cases of pinealocytoma, 1 case of medulloblastoma, and 1 case of meningioma) who were operated on in our hospital using the lateral OICST approach. Preoperative planning was performed using Surgical Theater®. The surgical corridor was formed using a retractor made from half of a syringe shortened according to the length of the surgical corridor. Preoperative lumbar drain was used. RESULTS: The pineal region tumors were completely resected in all cases. The mean craniotomy size was 2.22 × 1.79 cm. No long-term neurological deficits were reported. CONCLUSIONS: The use of semicircular retractors and intraoperative CSF drainage via a lumbar drain allows to form a small surgical corridor to the pineal region via minimally invasive craniotomy. This reduces traction and traumatization of the occipital lobe, as well as minimizes intra- and postoperative risks.

Minimally Invasive Approaches in Reoperations after Conventional Craniotomies : Case Series.

Objective: Reoperations are part of neurosurgical practice. In these cases, an already formed craniotomy seems the most logical and appropriate. However, reoperations via large approaches can be quite traumatic for the patient. Then minimally invasive approaches, being less traumatic, can be a good alternative. Methods: We describe 7 consecutive patients who underwent reoperations using minimally invasive approaches in the areas of conventional craniotomies. Surgical Theater® visualization platform was used for preoperative planning. The study evaluated the size of surgical approach, surgical efficacy, and the presence of complications. Results: The size of a minimally invasive craniotomy was significantly smaller than that of a conventional approach. The preoperative goals were achieved in all described cases. There were no complications in the early postoperative period. Although the anatomy of the operated brain region in reoperations is altered, keyhole approaches can be successfully used with the support of preoperative planning and intraoperative neuronavigation. Given that the goals of reoperations may differ from those of the primary surgery, and a large approach is more traumatic for the patient, minimally invasive craniotomy can be considered as a good alternative. The successful use of minimally invasive approaches in areas of conventional craniotomies reinforces the philosophy of keyhole neurosurgery. In cases where goals can be achieved using small approaches, it makes no sense to use large conventional ones. Conclusion: Minimally invasive approaches can be successfully used during reoperations in patients after conventional craniotomies.

Minimally Invasive Approaches in the Surgical Treatment of Intracranial Meningiomas: An Analysis of 54 Cases.

BACKGROUND: Intracranial meningiomas, being a fairly common disease in the population, often require surgical treatment, which, in turn, can completely heal the patient. The localization of meningiomas often influences treatment even if they are asymptomatic. By modernizing approaches to surgical treatment, it is possible to minimize intra- and postoperative risks, while achieving complete removal of the tumor. One of these methods is minimally invasive neurosurgery, the development of which in recent years allows it to compete with standard surgical methods. The purpose of this study was the objectification of minimally invasive approaches, such as the calculation of the craniotomy area and the ratio of craniotomy area to the resected tumor volume. METHODS: The retrospective study consisted of a group of 54 consecutive patients who were operated on in our neurosurgery clinic specialized on minimally invasive neurosurgery. Preoperative planning was carried out using the Surgical Theater visualization platform. Using this system, the tumor volume and craniotomy surface area were calculated. During the analysis, the symptoms before and after the surgery, classification of tumors, postoperative complications, further treatment and follow-up results were assessed. RESULTS: Twelve (22.2%) patients were men and 42 (77.8%) were women. The mean age of the group was 64.2 years (median 67.5). The craniotomy area ranged from 202 to 2,108 mm² (mean 631 mm²). Tumor volume ranged from 0.85 to 110.1 cm3 (mean 21.6 cm3). The craniotomy size of minimally invasive approaches to the skull base was 3-5 times smaller than standard approaches. Skull base meningiomas accounted for 19 cases (35.2%), convexity meningiomas for 26 cases (48.1%), and falx and tentorium meningiomas for 9 cases (16.7%). Three complications were reported: postoperative hemorrhage, CSF leakage, and ophthalmoplegia. Relapse was detected in 2 patients with a mean follow-up of 26.3 months (median 20). CONCLUSION: Minimally invasive approaches in the surgical treatment of intracranial meningiomas reduce the possibility of operating trauma by several times; they are safe and sufficient for complete removal of the tumor.

Angiomatoid fibrous histiocytoma: primary intracranial lesion with thoracic spine metastasis and a malignant course. Illustrative case.

BACKGROUND: Angiomatoid fibrous histiocytoma (AFH) is an exceptionally rare soft tissue neoplasm. This tumor primarily presents as a benign soft tissue lesion in children with an average age of 14 years. The standard treatment regimen is wide local excision with interval follow-up. However, newer reports have demonstrated malignant potential with the possibility of intracranial metastasis. OBSERVATIONS: A 45-year-old male with no soft tissue primary tumor presented with a primary intracranial lesion and thoracic spine metastasis refractory to chemotherapy and radiation treatment. LESSONS: This report illustrates the potential for a highly malignant nature of metastatic AFH. In addition, the authors demonstrate an incidence of AFH in a middle-aged male without a primary soft tissue or skin lesion. This report highlights the importance of prompt treatment and excision for AFH, as there is still little understanding of successful options for systemic therapy.

Multiple Intracranial Schwannomas of the Vestibular and Trigeminal Nerves: A Technical Note.

BACKGROUND: A schwannoma is a nerve sheath tumor that is formed by Schwann cells. Vestibular schwannomas are thought to account for the majority of intracranial schwannomas. Nonvestibular schwannomas account for about 10%, about half of which are trigeminal schwannomas. Multiple intracranial schwannomas originating from different cranial nerves are extremely rare. METHODS: We describe the clinical case of a 42-year-old female patient with vestibular schwannoma and multiple trigeminal schwannomas. RESULTS: That case shows how multiple trigeminal schwannomas were identified intraoperatively during elective surgery for vestibular schwannoma removal, most of which were resected. No new neurological deficits were observed in the patient. CONCLUSIONS: The presence of multiple intracranial schwannomas is extremely rare in neurosurgical practice and can change the intraoperative strategy and the course of the surgery.