Switchable origami adhesives.

Creating a reusable adhesive that can hold objects on a wall and can yet be easily removed al for researchers in the adhesives community for many years. Geckos and other climbing organisms demonstrate just this ability: to hold large loads (on-state) due to specialized digits and microstructures, yet they are also able to quickly peel their feet from a surface while climbing (off-state). Inspired by the simplicity of the gecko's geometric switching mechanism, we have investigated the use of origami design methods to create geometries that can transition from a stiff configuration to a more flexible and easily peeled configuration. Specifically, we examined three different origami designs (Kresling, Waterbomb and Ron Resch) fabricated in polycarbonate and supplemented with 3D printed structures. Although the polycarbonate could be coated with a commercial adhesive, we investigated the devices in contact with polydimethylsiloxane adhesive pads in order to chemically control interfaces and create a range of differing adhesion levels. We show that the devices are capable of moderate switching ratios (Fon/Foff up to ∼50). We give a simple model to aid design and provide many options for scaling design performance through size, adhesive strength or through repetition of the pattern beyond a single unit cell.

Future of Endovascular and Surgical Treatments of Atherosclerotic Intracranial Stenosis.

Intracranial atherosclerotic disease and resultant intracranial stenosis is a global leading cause of stroke, and poses an ongoing treatment challenge. Among patients with intracranial stenosis, those with hemodynamic compromise are at high risk for recurrent stroke despite medical therapy and risk factor modification. Revascularization of the hypoperfused territory is the most plausible treatment strategy for these high-risk patients, yet surgical and endovascular therapies have not yet shown to be sufficiently safe and effective in randomized controlled trials. Advances in diagnostic and therapeutic technologies have led to a resurgence of interest in surgical and endovascular treatment strategies, with a growing body of evidence to support their further evaluation in the treatment of select patient populations. This review outlines the current and emerging endovascular and surgical treatments and highlights promising future management strategies.

Persistent Primitive Olfactory Artery Aneurysm.

A middle-aged adult presented to the hospital with a high-grade aneurysmal subarachnoid hemorrhage. The patient was treated with endovascular coil embolization of a ruptured basilar tip aneurysm. Angiography demonstrated multiple other aneurysms, including type I persistent primitive olfactory artery aneurysm. After complete recovery and return to independence, the patient underwent elective treatment of the persistent primitive olfactory artery aneurysm with endovascular placement of a flow diversion stent. Persistent primitive olfactory artery is an extremely rare variant of the anterior cerebral artery with an incidence of 0.14% and a known increased risk of aneurysm formation.

Impact of anemia on acute ischemic stroke outcomes: A systematic review of the literature.

INTRODUCTION: Anemia has been reported in nearly 40% of acute ischemic stroke (AIS) patients and is linked to significant morbidity and disability. The presence of anemia is associated with worse outcomes in AIS, specifically in the presence of large vessel occlusion (LVO). An optimal hemoglobin (Hb) target specific to this pathology has not yet been established. The goal of this review is to systematically review literature that observes the association that exists between AIS outcomes and hemoglobin (Hb) levels. METHODS: A systematic review was performed in accordance with guidelines for the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to identify studies from 2008-2022. The following inclusion and exclusion criteria were used: studies of adult patients with AIS; must describe outcomes with regard to Hb levels in AIS (not limited to LVO); must be written in English. The clinical variables extracted included Length of Stay (LOS), modified rankin score (mRS), Hb levels, and mortality. RESULTS: A total of 1,154 studies were gathered, with 116 undergoing full text review. 31 studies were included in this review. The age of patients ranged from 61.4 to 77.8. The presence of anemia in AIS increased LOS by 1.7 days on average and these patients also have a 15.2% higher rate of mortality at one year, on average. DISCUSSION: This data suggests that the contemporary thresholds for treating anemia in AIS patients may be inadequate because anemia is strongly associated with poor outcomes (e.g., mRS>2 or mortality) and increased LOS in AIS patients. The current generalized Hb threshold for transfusion (7 g/dL) is also used in AIS patients, however, a more aggressive transfusion parameter should be further explored based on these findings. Further studies are required to confirm these findings and to determine if a more liberal RBCT threshold will result in clinical benefits.

Glioma stem cells activate platelets by plasma-independent thrombin production to promote glioblastoma tumorigenesis.

Background: The interaction between platelets and cancer cells has been underexplored in solid tumor models that do not metastasize, for example, glioblastoma (GBM) where metastasis is rare. Histologically, it is known that glioma stem cells (GSCs) are found in perivascular and pseudsopalisading regions of GBM, which are also areas of platelet localization. High platelet counts have been associated with poor clinical outcomes in many cancers. While platelets are known to promote the progression of other tumors, mechanisms by which platelets influence GBM oncogenesis are unknown. Here, we aimed to understand how the bidirectional interaction between platelets and GSCs drives GBM oncogenesis. Methods: Male and female NSG mice were transplanted with GSC lines and treated with antiplatelet and anti-thrombin inhibitors. Immunofluorescence, qPCR, and Western blots were used to determine expression of coagulation mechanism in GBM tissue and subsequent GSC lines. Results: We show that GSCs activate platelets by endogenous production of all the factors of the intrinsic and extrinsic coagulation cascades in a plasma-independent manner. Therefore, GSCs produce thrombin resulting in platelet activation. We further demonstrate that the endogenous coagulation cascades of these cancer stem cells are tumorigenic: they activate platelets to promote stemness and proliferation in vitro and pharmacological inhibition delays tumor growth in vivo. Conclusions: Our findings uncover a specific preferential relationship between platelets and GSCs that drive GBM malignancies and identify a therapeutically targetable novel interaction.

Emergent carotid endarterectomy and mechanical thrombectomy in tandem occlusion.

Background: Acute tandem occlusions, or occlusions of the extracranial portion of the internal carotid artery (ICA) with concurrent thromboembolism of the intracranial ICA or middle cerebral artery, poses a major clinical challenge, with patients suffering worse outcomes compared to those with single occlusions. Management of these lesions generally includes a combination of mechanical thrombectomy (MT) of the intracranial occlusion and stenting of the extracranial carotid lesion. In this manuscript, we describe a successful surgical method for achieving revascularization of tandem occlusions in the rare circumstance that the proximal lesion cannot be crossed endovascularly to gain intracranial access. Methods: Despite using our institution's standard protocol for achieving revascularization of such lesions, the extracranial occlusion could not be crossed endovascularly, and the case was converted to an emergent carotid endarterectomy (CEA) in the operating room. Once the endarterectomy was complete, intraoperative MT was performed before cervical incision closure to revascularization. Results: The patient recovered well postoperatively and was discharged with NIHSS of 2 due to minor facial palsy and minor dysarthria. Thirty-day follow-up revealed resolution of the prior neurologic deficits and an mRS of 1. Conclusion: Emergent CEA should be considered in the rare circumstance of being unable to cross the cervical occlusion during management of acute ischemic stroke with tandem occlusion.

Roughness tolerant pressure sensitive adhesives made of sticky crumpled sheets.

If an adhesive is meant to be temporary, roughness often poses a challenge for design. An adhesive could be made soft so that it can deform and increase surface contact but a softer material will in general hold a smaller load. Bioinspired adhesives, made with numerous microscale posts, show promise as roughness tolerant adhesives but are complicated to fabricate. In this work, we show how thin polymer sheets, when crumpled into a roughly spherical shape, form a very simple and roughness tolerant adhesive system. We use micro and macro-scale experiments to measure adhesion forces between various substrates and crumpled polydimethylsiloxane sheets. We find the force-displacement curves resemble probe-tack experiments of traditional pressure sensitive adhesives and that moderate tensile forces are required to initiate interfacial failure. Notably, we see that sticky crumples often perform better on long wavelength roughness than they do on smooth substrates. In order to improve the peak pull-off forces, we create a sticky crumple from a thin sheet of a glassy polymer, polycarbonate, coated with an adhesive layer. This elasto-plastic sticky crumple achieves high pull-off forces even on the rough surface of a landscaping brick.

Cervical carotid occlusion in acute ischemic stroke: Should we give tPA?

Background: Acute ischemic stroke (AIS) due to cervical internal carotid artery (cICA) occlusion is challenging to treat, with the lower revascularization rates, higher risk for complications, and poor response to thrombolytic therapy compared to isolated intracranial occlusions. While emergent revascularization through mechanical thrombectomy (MT) improves outcomes, the impact of tissue plasminogen activator (tPA) on outcomes in this subgroup of patients remains unclear. The objective of this study is to report our preliminary experience in treating AIS with cICA occlusions secondary to severe atherosclerotic stenosis and to establish the need for further clinical studies to determine the optimal intervention strategy for these lesions. Methods: Data were collected on patients who presented with acute cICA occlusion who underwent MT and either acute or staged carotid angioplasty and stenting. We compare patients who received tPA to those who did not, analyzing revascularization times, outcomes, and complications between the two populations, and discuss how this influenced our preferred treatment approach. Results: Twenty-one patients met inclusion criteria, seven of who received tPA and 14 did not receive tPA before surgical intervention. Procedural and functional outcomes were similar between the two populations. TPA administration correlated with a higher rate of vessel reocclusion in staged procedures and trended toward higher rates of symptomatic ICH and 90-day mortality. Conclusion: Emergent revascularization with acute cICA stenting carries advantages, but its safety is precluded by tPA administration. We suggest a trial which randomizes patients with cICA occlusions to receiving either tPA or dual antiplatelet therapy before surgical intervention, aiming to ultimately improved outcomes in these patients.

En Plaque Meningiomas: A Narrative Review.

Background En plaque meningiomas are a rare subtype of meningiomas that are frequently encountered in the spheno-orbital region. Characterized by a hyperostotic and dural invasive architecture, these tumors present unique diagnostic and treatment considerations. Objective The authors conduct a narrative literature review of clinical reports of en plaque meningiomas to summarize the epidemiology, clinical presentation, diagnostic criteria, and treatment considerations in treating en plaque meningiomas. Additionally, the authors present a case from their own experience to illustrate its complexity and unique features. Methods A literature search was conducted using the MEDLINE database using the following terminology in various combinations: meningioma , meningeal neoplasms, en plaque , skull base , spheno-orbital, and sphenoid wing . Only literature published in English between 1938 and 2018 was reviewed. All case series were specifically reviewed for sufficient data on treatment outcomes, and all literature was analyzed for reports of misdiagnosed cases. Conclusion En plaque meningiomas may present with a variety of symptoms according to their location and degree of bone invasion, requiring a careful diagnostic and treatment approach. While early and aggressive surgical resection is generally accepted as the optimal goal of treatment, these lesions require an individualized approach, with further investigation needed regarding the role of new therapies.

Aneurysmal subarachnoid hemorrhage, a presentation of metastatic carcinoma: A case report and review of the literature.

BACKGROUND: Neoplastic cerebral aneurysms related to metastatic processes are exceptionally rare and carry a dismal prognosis. Only four previous reports exist of neoplastic aneurysms secondary to metastatic adenocarcinoma, all of which were found to be lung cancer in origin. We present the fifth reported metastatic adenocarcinomatous cerebral aneurysm, and the first case is secondary to a non-lung cancer primary. CASE DESCRIPTION: The patient presented with complaining of headache and was found to have a large right-sided intraparenchymal hemorrhage and smaller left-sided hemorrhage on head CT, and CTA revealed a vascular pouch in the region of the hemorrhage. The patient showed sudden neurologic decline, and repeat imaging revealed enlargement of the hematoma with significant brain compression. The patient underwent emergent angiography revealing a distal cortical middle cerebral artery aneurysm, suspicious for mycotic etiology, which was treated through microsurgical excision at the time of hematoma evacuation. The aneurysm specimen was sent for cultures and pathology, revealing the diagnosis of metastatic non-small-cell carcinoma. Further inpatient workup did not reveal the primary neoplastic source. CONCLUSION: Although diagnostic workup should search for more common pathologic mimics than metastatic neoplastic cerebral aneurysms, clinicians must be able to recognize and expeditiously treat this devastating lesion. Further investigation and analysis of treatment options are necessary to better understand this rare pathology and improve patient outcomes.

A systematic review of telehealth for the delivery of emergent neurosurgical care.

INTRODUCTION: In 2017, the American Association of Neurological Surgeons and Congress of Neurological Surgeons published a statement in support of adopting telemedicine technologies in neurosurgery. The position statement detailed the principles for use and summarised the active efforts at the time to address barriers that limited expansion of use, such as reimbursement, liability, credentialing and patient confidentiality. The primary aim of this systematic literature review was to identify the available published literature on the application of telemedicine to neurosurgical patient care, with a specific focus on neurotrauma and emergent neurological conditions. METHODS: This Level II systematic review of the literature was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2009 guidelines. Following removal of duplicates, 359 studies were yielded from database query. Following application of inclusion and exclusion criteria, 78 articles were identified for full-text review. RESULTS: Full-text screening yielded a total of 11 studies for the final analysis. The study interventions took place in seven unique countries and included both developed and developing nations. Data captured spanned the years 1997 to 2019. The total cumulative number of patients who received neurosurgical telemedicine consultations captured by this review was 37,224. DISCUSSION: This review of the literature suggests that telemedicine in emergent settings offers safe, feasible, and cost-reducing methods of increasing access to high acuity neurosurgical care and may serve to limit unnecessary inter-facility transfers. As infrastructure and regulatory guidelines continue to evolve, neurosurgical patients, both domestic and abroad, will benefit from improved access to expertise afforded by telemedicine technologies.

History of Women in Neurosurgery (WINS).

In 2020, the Women in Neurosurgery (WINS) organization, a joint section of the AANS and Congress of Neurological Surgeons, celebrated 30 years since its inception. In this paper, the authors explore the history of WINS from its beginnings through its evolution over the past three decades. The achievements of the group are highlighted, as well as the broader achievements of the women in the neurosurgical community over this time period.

Laser interstitial thermotherapy (LITT) for the treatment of tumors of the brain and spine: a brief review.

INTRODUCTION: Laser Interstitial Thermotherapy (LITT; also known as Stereotactic Laser Ablation or SLA), is a minimally invasive treatment modality that has recently gained prominence in the treatment of malignant primary and metastatic brain tumors and radiation necrosis and studies for treatment of spinal metastasis has recently been reported. METHODS: Here we provide a brief literature review of the various contemporary uses for LITT and their reported outcomes. RESULTS: Historically, the primary indication for LITT has been for the treatment of recurrent glioblastoma (GBM). However, indications have continued to expand and now include gliomas of different grades, brain metastasis (BM), radiation necrosis (RN), other types of brain tumors as well as spine metastasis. LITT is emerging as a safe, reliable, minimally invasive clinical approach, particularly for deep seated, focal malignant brain tumors and radiation necrosis. The role of LITT for treatment of other types of tumors of the brain and for spine tumors appears to be evolving at a small number of centers. While the technology appears to be safe and increasingly utilized, there have been few prospective clinical trials and most published studies combine different pathologies in the same report. CONCLUSION: Well-designed prospective trials will be required to firmly establish the role of LITT in the treatment of lesions of the brain and spine.

Noninvasive evaluation of craniovertebral junction instability in 2 patients following Chiari decompression with rigid C-collar immobilization: illustrative cases.

BACKGROUND: The complex Chiari malformation has been identified in a subset of Chiari patients at higher risk for worsening symptoms following Chiari decompression. Although parameters such as the clivoaxial angle and the perpendicular distance of the dens to the line from the basion to the inferoposterior part of the C2 body (pBC2) have been evaluated to help with the prediction of risk, the decision to pursue an occipitocervical fusion in lower-risk patients does not come without inherent risk. OBSERVATIONS: The authors present 2 patients who had symptoms of worsening ventral brainstem compression following Chiari decompression, neither of whom was categorized in the highest risk category for occipitocervical instability. In addition, neither patient had gross instability on radiographic imaging. A trial with rigid C-collar immobilization provided relief of symptoms in both patients and allowed reassurance of the likelihood of success of occipitocervical fusion. LESSONS: In patients without clear radiographic instability following Chiari decompression, a C-collar trial may provide a noninvasive option for assessing the potential success of occipitocervical fusion.

Adhesion of a tape loop.

In this work, we revisit experimentally and theoretically the mechanics of a tape loop. Using primarily elastic materials (polydimethylsiloxane, PDMS, or polycarbonate, PC) and confocal microscopy, we monitor the shape as well as the applied forces during an entire cycle of compression and retraction of a half-loop compressed between parallel glass plates. We observe distinct differences in film shape during the cycle; points of equal applied force or equal plate separation differ in shape upon compression or retraction. To model the adhesion cycle in its entirety, we adapt the 'Sticky Elastica' of [T. J. W. Wagner et al., Soft Matter, 2013, 9, 1025-1030] to the tape loop geometry, which allows a complete analytical description of both the force balance and the film shape. We show that under compression the system is generally not sensitive to interfacial interactions, whereas in the limit of large separation of the confining parallel plates during retraction the system is well described by the peel model. Ultimately, we apply this understanding to the measurement of the energy release rate of a wide range of different cross-linker ratio PDMS elastomer half-loops in contact with glass. Finally, we show how the model illuminates an incredibly simple adhesion measurement technique, which only requires a ruler to perform.

A Liquid Biopsy to Assess Brain Tumor Recurrence: Presence of Circulating Mo-MDSC and CD14+ VNN2+ Myeloid Cells as Biomarkers That Distinguish Brain Metastasis From Radiation Necrosis Following Stereotactic Radiosurgery.

BACKGROUND: Brain metastases (BM) are the most common type of brain tumor malignancy in the US. They are also the most common indication for stereotactic radiosurgery (SRS). However, the incidence of both local recurrence and radiation necrosis (RN) is increasing as treatments improve. MRI imagery often fails to differentiate BM from RN; thus, patients must often undergo surgical biopsy or resection to obtain a definitive diagnosis. OBJECTIVE: To hypothesize that a marker of immunosuppression might serve as a surrogate marker to differentiate patients with active vs inactive cancer-including RN. METHODS: We thus purified and quantified Monocytic Myeloid-Derived Suppressor Cells (Mo-MDSC) by flow cytometry in patients proven by biopsy to represent BM or RN. RESULTS: We report the utility of the previously reported HLA-Dr-Vnn2 Index or DVI to discriminate recurrent BM from RN using peripheral blood. The presence of CD14+ HLA-DRneg/low Mo-MDSC is significantly increased in the peripheral blood of patients with brain metastasis recurrence compared to RN (Average 61.5% vs 7%, n = 10 and n = 12, respectively, P < .0001). In contrast, expression of VNN2 on circulating CD14+ monocytes is decreased in BM patients compared to patients with RN (5.5% vs 26.5%, n = 10 and n = 12, respectively, P = .0008). In patients with biopsy confirmed recurrence of brain metastasis, the average DVI was 11.65, whereas the average DVI for RN patients was consistently <1 (Avg. of 0.17). CONCLUSION: These results suggest that DVI could be a useful diagnostic tool to differentiate recurrent BM from RN using a minimally invasive blood sample.

Comparative epidemiology of gliosarcoma and glioblastoma and the impact of Race on overall survival: A systematic literature review.

OBJECTIVE: Gliosarcoma (GSM) is a rare subtype of glioblastoma (GBM) that accounts for approximately four percent of high-grade gliomas. There is scarce epidemiological data on patients with GSM as a distinct subgroup of GBM. METHODS: A systematic literature review was performed of peer-reviewed databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to evaluate the impact of race and ethnicity on survival in patients with GSM compared to patients with GBM. RESULTS: Following initial abstract screening, a total of 138 articles pertaining to GSM and 275 pertaining to GBM met criteria for full-text review, with 5 and 27 articles included in the final analysis for GSM and GBM, respectively. The majority of patients in both cohorts were non-Hispanic Whites, representing 85.6 % of total GSM patients and 87.7 % of GBM patients analyzed. Two GSM studies stratified survival by race, with one reporting the longest median survival for the Hispanic population of 10.6 months and the shortest median survival for the Asian population of 9 months. Among the GBM studies analyzed, the majority of studies reported shorter survival and higher risk of mortality among White Non-Hispanics compared to non-White patients; and of the 15 studies which reported data for the Asian population, 12 studies reported this race category to have the longest survival compared to all other races studied. Younger age, female sex, MGMT promoter methylation status, and adjuvant chemoradiation therapy were associated with improved survival in both GSM and GBM cohorts, although these were not further stratified by race. CONCLUSION: GSM portends a similarly poor prognosis to other GBM subtypes; however, few studies exist which have examined factors associated with differences in survival between these histologic variants. This review of the literature suggests there is a possible association between race and survival for patients with GBM, however data supporting this conclusion for patients with GSM is lacking. These findings suggest that GSM is a distinct disease from other GBM subtypes, with epidemiologic differences that should be further explored.

Outcomes and Clinical Characteristics of Intracranial Hemorrhage in Patients with Hematologic Malignancies: A Systematic Literature Review.

BACKGROUND: Many clinical and demographic factors can influence survival of patients with hematologic malignancies who have intracranial hemorrhages (ICHs). Understanding the influence of these factors on patient survival can guide treatment decisions and may inform prognostic discussions. We conducted a systematic literature review to determine survival of patients with intracranial hemorrhages and concomitant hematologic malignancy. METHODS: A systematic literature review was conducted and followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. PubMed/MEDLINE, Web of Science, Ovid, SCOPUS, and Embase databases were queried with the following terms: ("intracranial hemorrhages" OR "brain hemorrhage" OR "cerebral hemorrhage" OR "subdural hematoma" OR "epidural hematoma" OR "intraparenchymal hemorrhage") AND ("Hematologic Neoplasms" OR "Myeloproliferative Disorders" OR "Myelofibrosis" OR "Essential thrombocythemia" OR "Leukemia"). Abstracts and articles were screened according to inclusion and exclusion criteria that were determined a priori. RESULTS: Literature review yielded 975 abstracts from which a total of 68 full-text articles were reviewed. Twelve articles capturing 634 unique patients were included in the final qualitative analysis. Median overall survival for all patients ranged from 20 days to 1.5 months while median overall survival for the subset of patients having ICH within 10 days of diagnosis of hematologic malignancy was 5 days. Intraparenchymal hemorrhages, multiple foci of hemorrhage, transfusion-resistant low platelet counts, leukocytosis, low Glasgow Coma Scale scores at presentation, and ICH early in treatment course were associated with worse outcomes. CONCLUSIONS: Survival for patients with hematologic malignancies and concomitant ICHs remains poor. Early detection, recognition of poor prognostic factors, and correction of hematologic abnormalities essential to prevention and treatment of ICHs in this patient population.