Highly accelerated non-contrast-enhanced time-resolved 4D MRA using stack-of-stars golden-angle radial acquisition with a self-calibrated low-rank subspace reconstruction.

PURPOSE: To develop a highly accelerated non-contrast-enhanced 4D-MRA technique by combining stack-of-stars golden-angle radial acquisition with a modified self-calibrated low-rank subspace reconstruction. METHODS: A low-rank subspace reconstruction framework was introduced in radial 4D MRA (SUPER 4D MRA) by combining stack-of-stars golden-angle radial acquisition with control-label k-space subtraction-based low-rank subspace modeling. Radial 4D MRA data were acquired and reconstructed using the proposed technique on 12 healthy volunteers and 1 patient with steno-occlusive disease. The performance of SUPER 4D MRA was compared with two temporally constrained reconstruction methods (golden-angle radial sparse parallel [GRASP] and GRASP-Pro) at different acceleration rates in terms of image quality and delineation of blood dynamics. RESULTS: SUPER 4D MRA outperformed the other two reconstruction methods, offering superior image quality with a clear background and detailed delineation of cerebrovascular structures as well as great temporal fidelity in blood flow dynamics. SUPER 4D MRA maintained excellent performance even at higher acceleration rates. CONCLUSIONS: SUPER 4D MRA is a promising technique for highly accelerating 4D MRA acquisition without comprising both temporal fidelity and image quality.

Cilostazol for the management of moyamoya disease: a systematic review of the early evidence, efficacy, safety, and future directions.

Surgical revascularization remains the standard treatment for symptomatic moyamoya disease (MMD). As with any major surgical treatment, revascularization is associated with risks and limitations, denoting the need for noninvasive treatments to improve ischemic symptoms and prevent strokes. Cilostazol is a selective phosphodiesterase III inhibitor with antiplatelet, antithrombotic, and vasodilatory effects commonly used in peripheral vascular disease. Clinical studies assessing the efficacy of cilostazol in the management of stroke and MMD were recently reported, although a comprehensive assessment of the overall evidence is lacking. A systematic scoping review was conducted to assess the early evidence on cilostazol administration in patients with MMD. The inclusion criteria encompassed original human studies primarily focused on cilostazol's safety, efficacy, or utilization in managing MMD patients. A search of the PubMed database was conducted in June 2023, yielding 5 peer-reviewed publications that satisfied the inclusion criteria and were subjected to narrative synthesis. Risk of bias assessment was not applicable due to the scoping nature of this review. East Asian studies demonstrate increasing rates of cilostazol prescriptions for patients with MMD. In a large population-based study, cilostazol was compared to other antiplatelet medications and yielded the largest decrease in mortality among patients with newly diagnosed MMD. Other studies reported significant improvements in cerebral blood flow and cognitive function, which were deemed to be independent of one another. There are limited data on the safety profile of cilostazol in the MMD population, although the evidence derived from various studies performed in the general stroke population can likely provide insights into its potential utility in MMD patients. Cilostazol targets several critical pathways involved in the pathophysiology of MMD. The evidence corroborates the potential benefits of cilostazol for the management of MMD, although these findings should be interpreted with caution due to the small number of studies and lack of randomized trials. Subgroups of patients need to be identified who can safely undergo medical management in lieu of revascularization surgery or to improve surgical outcomes. Additional studies are needed to assess the efficacy and safety of cilostazol therapy, especially in Western populations.

Role of botulinum neurotoxin-A in cerebral revascularization graft vasospasm prevention: current state of knowledge.

Graft stenosis and occlusion remain formidable complications in cerebral revascularization procedures, which can lead to significant morbidity and mortality. Graft vasospasm can result in early postoperative graft stenosis and occlusion and is believed to be at least partially mediated through adrenergic pathways. Despite various published treatment protocols, there is no single effective spasmolytic agent. Multiple factors, including anatomical and physiological variability in revascularization conduits, patient age, and comorbidities, have been associated with graft vasospasm pathogenesis and response to spasmolytics. The ideal spasmolytic agent thus likely needs to target multiple pathways to exert a generalizable therapeutic effect. Botulinum toxin (BTX)-A is a powerful neurotoxin widely used in clinical practice for the treatment of a variety of spastic conditions. Although its commonly described paradigm of cholinergic neural transmission blockade has been widely accepted, evidence for other mechanisms of action including inhibition of adrenergic transmission have been described in animal studies. Recently, the first pilot study demonstrating clinical use of BTX-A for cerebral revascularization graft spasm prevention has been reported. In this review, the mechanistic basis and potential future clinical role of BTX-A in graft vasospasm prevention is discussed.

EC-IC bypass for cerebral revascularization following skull base tumor resection: Current practices and innovations.

Complex skull base tumors can involve critical vessels of the head and neck. To achieve a gross total resection, vessel sacrifice may be necessary. In cases where vessel sacrifice will cause symptomatic cerebral ischemia, surgical revascularization is required. The purpose of this paper is to review cerebral revascularization for skull base tumors, the indications for these procedures, outcomes, advances, and future directions.

Combined Direct and Indirect Cerebral Revascularization Using Local and Flow-Through Flaps.

BACKGROUND: Extracranial-intracranial bypass is indicated in ischemic disease such as moyamoya, certain intracranial aneurysms, and other complex neurovascular diseases. In this article, we present our series of local and flow-through flaps for cerebral revascularization as an additional tool to provide direct and indirect revascularization and/or soft tissue coverage. METHODS: A retrospective review of a prospectively maintained database was performed identifying nine patients. Ten direct arterial bypass procedures with nine indirect revascularization and/or soft tissue reconstruction were performed. RESULTS: Indications for arterial bypass included intracranial aneurysm (n = 2) and moyamoya disease (n = 8). Indications for soft tissue transfer included infected cranioplasty (one) and indirect cerebral revascularization (eight). Four flow-through flaps and five pedicled flaps were used including a flow-through radial forearm fasciocutaneous flap (one), flow-through radial forearm fascial flaps (three), and pedicled temporoparietal fascial (TPF) flaps with distal end anastomosis (five). The superficial temporal vessels (seven) and facial vessels (two) were used as the vascular inflow. Arterial bypass was established into the middle cerebral artery (six) and anterior communicating artery (three). There were no intraoperative complications. All flaps survived with no donor-site complications. In one case of flow-through TPF flap, the direct graft failed, but the indirect flap remained vascularized. CONCLUSION: Local and flow-through flaps can improve combined direct and indirect revascularization and provide soft tissue reconstruction. Minimal morbidity has been encountered in early outcomes though long-term results remain under investigation for these combined neurosurgery and plastic surgery procedures. LEVEL OF EVIDENCE: The level of evidence is IV.

Selective embolization of ruptured feeding artery aneurysm followed by resection of arteriovenous malformation.

This is the case of a man in his 40s who suffered sudden collapse into a deep coma as a result of a ruptured arteriovenous malformation (AVM) feeding artery aneurysm within the lateral ventricle. The ruptured aneurysm was successfully treated with Onyx embolization of the feeding pedicle. The AVM and the feeding artery aneurysm were then removed via a transcallosal approach. This case highlights the utility of interrogating the AVM with microcatheterization of the feeding pedicles in order to define the exact anatomical features necessary for treatment planning. It also reviews the anatomy of the choroidal fissure. The video can be found here: https://youtu.be/UeqFzhTRU1Q .

Surgical management of skull base tumors.

AIM: To present a review of the contemporary surgical management of skull base tumors. BACKGROUND: Over the last two decades, the treatment of skull base tumors has evolved from observation, to partial resection combined with other therapy modalities, to gross total resection and no adjuvant treatment with good surgical results and excellent clinical outcomes. MATERIALS AND METHODS: The literature review of current surgical strategies and management of skull base tumors was performed and complemented with the experience of Barrow Neurological Institute. RESULTS: Skull base tumors include meningiomas, pituitary tumors, sellar/parasellar tumors, vestibular and trigeminal schwannomas, esthesioneuroblastomas, chordomas, chondrosarcomas, and metastases. Surgical approaches include the modified orbitozygomatic, pterional, middle fossa, retrosigmoid, far lateral craniotomy, midline suboccipital craniotomy, and a combination of these approaches. The selection of an appropriate surgical approach depends on the characteristics of the patient and the tumor, as well as the experience of the neurosurgeon. CONCLUSION: Modern microsurgical techniques, diagnostic imaging, intraoperative neuronavigation, and endoscopic technology have remarkably changed the concept of skull base surgery. These refinements have extended the boundaries of tumor resection with minimal morbidity.

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.

Molecular and cellular biology of cerebral arteriovenous malformations: a review of current concepts and future trends in treatment.

OBJECT: Arteriovenous malformations (AVMs) are classically described as congenital static lesions. However, in addition to rupturing, AVMs can undergo growth, remodeling, and regression. These phenomena are directly related to cellular, molecular, and physiological processes. Understanding these relationships is essential to direct future diagnostic and therapeutic strategies. The authors performed a search of the contemporary literature to review current information regarding the molecular and cellular biology of AVMs and how this biology will impact their potential future management. METHODS: A PubMed search was performed using the key words "genetic," "molecular," "brain," "cerebral," "arteriovenous," "malformation," "rupture," "management," "embolization," and "radiosurgery." Only English-language papers were considered. The reference lists of all papers selected for full-text assessment were reviewed. RESULTS: Current concepts in genetic polymorphisms, growth factors, angiopoietins, apoptosis, endothelial cells, pathophysiology, clinical syndromes, medical treatment (including tetracycline and microRNA-18a), radiation therapy, endovascular embolization, and surgical treatment as they apply to AVMs are discussed. CONCLUSIONS: Understanding the complex cellular biology, physiology, hemodynamics, and flow-related phenomena of AVMs is critical for defining and predicting their behavior, developing novel drug treatments, and improving endovascular and surgical therapies.

Contemporary management of spinal AVFs and AVMs: lessons learned from 110 cases.

OBJECT: Spinal arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs) are rare, complex spinal vascular lesions that are challenging to manage. Recently, understanding of these lesions has increased thanks to neuroimaging technology. Published reports of surgical results and clinical outcome are limited to small series. The authors present a large contemporary series of patients with spinal AVFs and AVMs who were treated at Barrow Neurological Institute in Phoenix, Arizona. METHODS: Retrospective detailed review of a prospective vascular database was performed for all patients with spinal AVFs and AVMs treated between 2000 and 2013. Patient demographic data, AVF and AVM characteristics, surgical results, clinical outcomes, complications, and long-term follow-up were reviewed. RESULTS: Between 2000 and 2013, 110 patients (57 male and 53 female) underwent obliteration of spinal AVFs and AVMs. The mean age at presentation was 42.3 years (range 18 months-81 years). There were 44 patients with AVFs and 66 with AVMs. The AVM group included 27 intramedullary, 21 conus medullaris, 12 metameric, and 6 extradural. The most common location was thoracic spine (61%), followed by cervical (22.7%), lumbar (14.5%), and sacral (1.8%). The most common presenting signs and symptoms included paresis/paralysis (75.5%), paresthesias (60%), pain (51.8%), bowel/bladder dysfunction (41.8%), and myelopathy (36.4%). Evidence of rupture was seen in 26.4% of patients. Perioperative embolization was performed in 42% of patients. Resection was performed in 95 patients (86.4%). Embolization alone was the only treatment in 14 patients (12.7%). One patient was treated with radiosurgery alone. Angiographically verified AVF and AVM obliteration was achieved in 92 patients (83.6%). At a mean follow-up duration of 30.5 months (range 1-205 months), 43 patients (97.7%) with AVFs and 57 (86.4%) with AVMs remained functionally independent (McCormick Scale scores ≤ 2). Perioperative complications were seen in 8 patients (7%). No deaths occurred. Temporary neurological deficits were observed in 27 patients (24.5%). These temporary deficits recovered 6-8 weeks after treatment. Recurrence was identified in 6 patients (13.6%) with AVFs and 10 (15.2%) with AVMs. CONCLUSIONS: Spinal AVFs and AVMs are complex lesions that should be considered for surgical obliteration. Over the last several decades the authors have changed surgical strategies and management to achieve better clinical outcomes. Transient neurological deficit postoperatively is a risk associated with intervention; however, clinical outcomes appear to exceed the natural history based on patients' ability to recover during the follow-up period. Due to the recurrence rate associated with these lesions, long-term follow-up is required.

Racial and socioeconomic disparities in access to mechanical revascularization procedures for acute ischemic stroke.

BACKGROUND: Mechanical revascularization procedures performed for treatment of acute ischemic stroke have increased in recent years. Data suggest association between operative volume and mortality rates. Understanding procedural allocation and patient access patterns is critical. Few studies have examined these demographics. METHODS: Data were collected from the 2008 Nationwide Inpatient Sample database. Patients hospitalized with ischemic stroke and the subset of individuals who underwent mechanical thrombectomy were characterized by race, payer source, population density, and median wealth of the patient's zip code. Demographic data among patients undergoing mechanical thrombectomy procedures were examined. Stroke admission demographics were analyzed according to thrombectomy volume at admitting centers and patient demographics assessed according to the thrombectomy volume at treating centers. RESULTS: Significant allocation differences with respect to frequency of mechanical thrombectomy procedures among stroke patients existed according to race, expected payer, population density, and wealth of the patient's zip code (P < .0001). White, Hispanic, and Asian/Pacific Islander patients received endovascular treatment at higher rates than black and Native American patients. Compared with the white stroke patients, black (P < .001), Hispanic (P < .001), Asian/Pacific Islander (P < .001), and Native American stroke patients (P < .001) all demonstrated decreased frequency of admission to hospitals performing mechanical thrombectomy procedures at high volumes. Among treated patients, blacks (P = .0876), Hispanics (P = .0335), and Asian/Pacific Islanders (P < .001) demonstrated decreased frequency in mechanical thrombectomy procedures performed at high-volume centers when compared with whites. While present, socioeconomic disparities were not as consistent or pronounced as racial differences. CONCLUSIONS: We demonstrate variances in endovascular acute stroke treatment allocation according to racial and socioeconomic factors in 2008. Efforts should be made to monitor and address potential disparities in treatment utilization.

Three-Vessel Anastomosis for Direct Multiterritory Cerebral Revascularization: Case Series.

BACKGROUND AND OBJECTIVE: Cerebral revascularization of multiple territories traditionally requires multiple constructs, serial anastomoses, or a combination of direct and indirect approaches. A novel 3-vessel anastomosis technique allows for direct, simultaneous multiterritory cerebral revascularization using a single interposition graft. We herein present our experience with this approach. METHODS: Retrospective review of perioperative data and outcomes for patients undergoing multiterritory cerebral revascularization using a 3-vessel anastomosis from 2019 to 2023. RESULTS: Five patients met inclusion criteria (median age 53 years [range 12-73]). Three patients with complex middle cerebral artery aneurysms (1 ruptured) were treated with proximal ligation or partial/complete clip trapping and multiterritory external carotid artery-M2-M2 revascularization using a saphenous vein interposition graft. Two patients with moyamoya disease, prior strokes, and predominately bilateral anterior cerebral artery hypoperfusion were treated with proximal superficial temporal artery-A3-A3 revascularization using a radial artery or radial artery fascial flow-through free flap graft. No patients experienced significant surgery-related ischemia. Bypass patency was 100%. One patient had new strokes from vasospasm after subarachnoid hemorrhage. One patient required a revision surgery for subdural hematoma evacuation and radial artery fascial flow-through free flap debridement, without affecting bypass patency or neurologic outcome. On hospital discharge, median Glasgow Outcome Scale and modified Rankin Scale scores were 4 (range 3-5) and 2 (range 0-5), respectively. On follow-up, 1 patient died from medical complications of their presenting stroke; Glasgow Outcome Scale and modified Rankin Scale scores were otherwise stable or improved. CONCLUSION: The 3-vessel anastomosis technique can be considered for simultaneous revascularization of multiple intracranial territories.

Functional ultrasound imaging of human brain activity through an acoustically transparent cranial window.

Visualization of human brain activity is crucial for understanding normal and aberrant brain function. Currently available neural activity recording methods are highly invasive, have low sensitivity, and cannot be conducted outside of an operating room. Functional ultrasound imaging (fUSI) is an emerging technique that offers sensitive, large-scale, high-resolution neural imaging; however, fUSI cannot be performed through the adult human skull. Here, we used a polymeric skull replacement material to create an acoustic window compatible with fUSI to monitor adult human brain activity in a single individual. Using an in vitro cerebrovascular phantom to mimic brain vasculature and an in vivo rodent cranial defect model, first, we evaluated the fUSI signal intensity and signal-to-noise ratio through polymethyl methacrylate (PMMA) cranial implants of different thicknesses or a titanium mesh implant. We found that rat brain neural activity could be recorded with high sensitivity through a PMMA implant using a dedicated fUSI pulse sequence. We then designed a custom ultrasound-transparent cranial window implant for an adult patient undergoing reconstructive skull surgery after traumatic brain injury. We showed that fUSI could record brain activity in an awake human outside of the operating room. In a video game "connect the dots" task, we demonstrated mapping and decoding of task-modulated cortical activity in this individual. In a guitar-strumming task, we mapped additional task-specific cortical responses. Our proof-of-principle study shows that fUSI can be used as a high-resolution (200 µm) functional imaging modality for measuring adult human brain activity through an acoustically transparent cranial window.

Open Surgical Treatment of Middle Cerebral Artery Aneurysms: A Single-Center Series in the Endovascular Era.

OBJECTIVE: We review the outcomes of open surgical treatment of middle cerebral artery aneurysms (MCAAs) at a single center, focusing on aneurysm obliteration rates and functional outcomes at the most recent follow-up. These findings can be used for future comparisons of surgical outcomes with MCAAs. METHODS: We retrospectively reviewed cases from a prospectively maintained database of patients receiving open surgical treatment for ruptured or unruptured MCAAs between July 2014 and December 2022. We utilized patients' modified Rankin Scale (mRS) score and Glasgow Outcome Scale score as functional outcome measures. Means, standard deviations, medians, and interquartile ranges were calculated, and a student's t test or its nonparametric equivalent was used to compare subgroups. RESULTS: One hundred fifty patients (114 women, 76%; mean age 55.0 ± 14.7 years) with a total of 156 MCAAs comprised 152 cases; 85 (56%) ruptured and 71 (46%) unruptured. Bypass was performed in 34 cases (22.4%); 18 ruptured (51.4%) and 16 unruptured (48.6%). Intraoperative rupture occurred in 5 (5%) ruptured and 1 (2%) unruptured cases. Onwe hundred forty-five patients (95.4%) had aneurysm obliteration with initial surgery, with 98.4% of patients having complete occlusion at 40.2± 65.5 weeks of follow-up. Intrahospital mortality occurred in 7 (6.9%) ruptured versus 1 (2.0%) unruptured case. Fifty-two (51.5%) of the ruptured compared to 43 (86%) unruptured patients were discharged home, with the remaining patients requiring inpatient rehabilitation or long-term hospitalization. The ruptured group had a mean hospital stay of 18.4 ± 10.5 days versus. 5.7 ± 6.0 days for unruptured. Length of stay, discharge mRS/ Glasgow Outcome Scale, and mRS at 4-6 weeks favored unruptured cases (P < 0.0001-0.0336). Mean change in mRS from presentation to last follow-up favored ruptured cases (-0.7 ± 1.2 vs. -0.04 ± 1.2, P = 0.0215). CONCLUSIONS: Open surgery remains a safe and definitive treatment option for MCAAs in the endovascular era.

Neurotropism of SARS-CoV-2: A Pathological Examination of Neurosurgical Specimens.

BACKGROUND AND OBJECTIVES: Neurological manifestations may occur in more than 80% of patients hospitalized with COVID-19 infection, including severe disruptions of the central nervous system (CNS), such as strokes, encephalitis, or seizures. Although the primary pathophysiological mechanism for the effects of COVID-19 in CNS remains unknown, evidence exists for both direct injury from neuroinvasion and indirect effects from disruptions in systemic inflammatory and coagulation pathways. In this study, we analyzed CNS tissue from living patients to better understand these processes. METHODS: With institutional review board approval and patient consent, samples that would be otherwise discarded from patients with active or recent (within 6 days of surgery) COVID-19 infection undergoing neurosurgical intervention were collected and tested for the presence of SARS-CoV-2 using immunohistochemistry, in situ hybridization, electron microscopy, and reverse transcription polymerase chain reaction. RESULTS: Five patients with perioperative mild-to-moderate COVID-19 infection met inclusion criteria (2 male, 3 female; mean age 38.8 ± 13.5 years). Neurosurgical diagnoses included a glioblastoma, a ruptured arteriovenous malformation, a ruptured posterior inferior cerebellar artery aneurysm, a middle cerebral artery occlusion, and a hemorrhagic pontine cavernous malformation. Samples analyzed included the frontal lobe cortex, olfactory nerve, arteriovenous malformation/temporal lobe parenchyma, middle cerebral artery, cerebellum, and cavernous malformation/brainstem parenchyma. Testing for the presence of SARS-CoV-2 was negative in all samples. CONCLUSION: The CNS is likely not a significant viral reservoir during mild-to-moderate COVID-19 infection, although direct neuroinvasion is not definitively excluded. Additional testing to help elucidate the relative contributions of direct and indirect pathways for CNS injury from COVID is warranted.

Direct V3 Vertebral Artery Access for Embolization of Partially Thrombosed Fusiform Basilar Trunk Aneurysm: Technical Case Instruction.

BACKGROUND AND IMPORTANCE: Fusiform vertebrobasilar aneurysms carry significant morbidity. Endovascular strategies are preferred; however, unsafe or unfeasible access can call for innovative strategies. CLINICAL PRESENTATION: An octogenarian patient with an enlarging fusiform proximal basilar artery aneurysm causing a sixth nerve palsy was found to have multiple anatomic features that precluded a transradial or transfemoral endovascular approach. She was thus treated with direct microsurgical access of the V3 segment of the vertebral artery for subsequent coil embolization and flow diversion. CONCLUSION: This case introduces a novel combined microsurgical and endovascular strategy for treating a complex partially thrombosed fusiform basilar artery aneurysm. This approach should be reserved only for patients where conventional endovascular access is dangerous or unfeasible.

A Novel Bypass Technique to Prevent Vexing Spinal Cord Ischemia in Endovascular Thoracoabdominal Aortic Intervention.

BACKGROUND: Spinal cord ischemia remains a devastating complication when treating patients with complex thoracoabdominal aortic aneurysms using fenestrated endovascular aortic repair. This approach is progressively deployed. However, to date, no strategy has been identified to reduce the feared risk of spinal cord ischemia. OBJECTIVE: To introduce a novel bypass technique using a customized composite graft to create a direct extra-anatomic revascularization before fenestrated endovascular aortic repair in patients with high-risk of spinal cord ischemia. METHODS: To demonstrate this novel concept, we present here a clinical case that reports the strategy of this novel concept in detail. An 83-year-old man with medical history of endovascular repair of an abdominal aortic aneurysm and thoracic aorta presented with a type IA endoleak, located along the posterior superior aspect of the aortic stent graft adjacent to the lumbar arteries. A multidisciplinary plan was developed, which included a novel bypass from the profunda femoris to the left L1 radicular artery before fenestrated endovascular aortic repair to prevent spinal cord ischemia. RESULTS: The patient successfully receives the novel extra-anatomic revascularization bypass before fenestrated endovascular aortic repair. During the first implementation of this strategy, no intraoperative difficulties and postoperative complications were observed. CONCLUSION: This case demonstrates a novel surgical technique before fenestrated endovascular aortic repair for prevention of spinal cord ischemia. In addition, this concept provides a promising direction to not only complement the existing surgical techniques but also to generate more future innovations.

Surgical Outcomes Following Vestibular Schwannoma Resection in Patients over the Age of Sixty-five.

Objective Vestibular schwannoma (VS) are benign, often slow growing neoplasms. Some institutions opt for radiosurgery in symptomatic patients of advanced age versus surgical resection. The aim of the study is to analyze surgical outcomes of VS in patients over the age of 65 who were either not candidates for or refused radiosurgery. Methods This includes retrospective analysis of VS patients between 1988 and 2020. Demographics, tumor characteristics, surgical records, and clinical outcomes were recorded. Patient preference for surgery over radiosurgery was recorded in the event that patients were offered both. Facial nerve outcomes were quantified using House-Brackmann (HB) scores. Tumor growth was defined by increase in size of >2 mm. Results In total, 64 patients were included of average age 72.4 years (65-84 years). Average maximum tumor diameter was 29 mm (13-55 mm). Forty-five patients were offered surgery or GKRS, and chose surgery commonly due to radiation aversion (48.4%). Gross total resection was achieved in 39.1% ( n = 25), near total 32.8% ( n = 21), and subtotal 28.1% ( n = 18). Average hospitalization was 5 days [2-17] with 75% ( n = 48) discharged home. Postoperative HB scores were good (HB1-2) in 43.8%, moderate (HB3-4) in 32.8%, and poor (HB5-6) in 23.4%. HB scores improved to good in 51.6%, moderate in 31.3%, and remained poor in 17.1%, marking a rate of facial nerve improvement of 10.9%. Tumor control was achieved in 95.3% of cases at an average follow-up time of 37.8 months. Conclusion VS resection can be safely performed in patients over the age of 65. Advanced age should not preclude a symptomatic VS patient from being considered for surgical resection.

A window to the brain: ultrasound imaging of human neural activity through a permanent acoustic window.

Recording human brain activity is crucial for understanding normal and aberrant brain function. However, available recording methods are either highly invasive or have relatively low sensitivity. Functional ultrasound imaging (fUSI) is an emerging technique that offers sensitive, large-scale, high-resolution neural imaging. However, fUSI cannot be performed through adult human skull. Here, we use a polymeric skull replacement material to create an acoustic window allowing ultrasound to monitor brain activity in fully intact adult humans. We design the window through experiments in phantoms and rodents, then implement it in a participant undergoing reconstructive skull surgery. Subsequently, we demonstrate fully non-invasive mapping and decoding of cortical responses to finger movement, marking the first instance of high-resolution (200 µm) and large-scale (50 mmx38 mm) brain imaging through a permanent acoustic window.