Diffusion-Weighted Imaging Fluid-Attenuated Inversion Recovery Mismatch on Portable, Low-Field Magnetic Resonance Imaging Among Acute Stroke Patients.

OBJECTIVE: For stroke patients with unknown time of onset, mismatch between diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) can guide thrombolytic intervention. However, access to MRI for hyperacute stroke is limited. Here, we sought to evaluate whether a portable, low-field (LF)-MRI scanner can identify DWI-FLAIR mismatch in acute ischemic stroke. METHODS: Eligible patients with a diagnosis of acute ischemic stroke underwent LF-MRI acquisition on a 0.064-T scanner within 24 h of last known well. Qualitative and quantitative metrics were evaluated. Two trained assessors determined the visibility of stroke lesions on LF-FLAIR. An image coregistration pipeline was developed, and the LF-FLAIR signal intensity ratio (SIR) was derived. RESULTS: The study included 71 patients aged 71 ± 14 years and a National Institutes of Health Stroke Scale of 6 (interquartile range 3-14). The interobserver agreement for identifying visible FLAIR hyperintensities was high (κ = 0.85, 95% CI 0.70-0.99). Visual DWI-FLAIR mismatch had a 60% sensitivity and 82% specificity for stroke patients <4.5 h, with a negative predictive value of 93%. LF-FLAIR SIR had a mean value of 1.18 ± 0.18 <4.5 h, 1.24 ± 0.39 4.5-6 h, and 1.40 ± 0.23 >6 h of stroke onset. The optimal cut-point for LF-FLAIR SIR was 1.15, with 85% sensitivity and 70% specificity. A cut-point of 6.6 h was established for a FLAIR SIR <1.15, with an 89% sensitivity and 62% specificity. INTERPRETATION: A 0.064-T portable LF-MRI can identify DWI-FLAIR mismatch among patients with acute ischemic stroke. Future research is needed to prospectively validate thresholds and evaluate a role of LF-MRI in guiding thrombolysis among stroke patients with uncertain time of onset. ANN NEUROL 2024.

Transvenous embolization of noncavernous dural arteriovenous fistulas (dAVFs): A systematic review and meta-analysis.

BACKGROUND: Intracranial dural arteriovenous fistulas (dAVFs) are abnormal connections between arteries and veins within the dura mater. Various treatment modalities, such as surgical ligation, endovascular intervention, and radiosurgery, aim to close the fistulous connection. Although transvenous embolization (TVE) is the preferred method for carotid-cavernous fistulas, its description and outcomes for noncavernous dAVFs vary. This has prompted a systematic review and meta-analysis to comprehensively assess the effectiveness of TVE in treating noncavernous dAVFs, addressing variations in outcomes and techniques. METHODS: We searched PubMed and Embase, spanning from the earliest records to December 2022, to identify pertinent English-language articles detailing the utilization of TVE. We focused on specific procedural details, outcomes, and complications in patients older than 18 years. The data collected and analyzed comprised the sample size, number of fistulas, publication specifics, presenting symptoms, fistula grades, and pooled rates of embolizations, outcomes, follow-up information, and complications. RESULTS: From a total of 565 screened articles, 15 retrospective articles encompassing 166 patients spanning across seven countries met the inclusion criteria. Their Newcastle-Ottawa scores ranged from 6 to 8. Intraprocedural complication rate was 10% (95% confidence interval [CI] = 5.9-17.1) and in-hospital postprocedural complication rate was 5.4% (95% CI = 2.8-10.6). Prevalence of in-hospital mortality was 5.5% (95% CI = 2.9-10.6). Complication rate during follow-up was 8.6% (95% CI = 4.7-15.7) with fistula rupture occurring in 5.5% (95% CI = 2.6-11.6) of patients. Complete obliteration rate at final angiographic follow-up was 94.9% (95% CI = 90.3-99.9). Symptoms improved in 95% (95% CI = 89.8-100) of patients at final follow-up. CONCLUSION: To our knowledge, we present the first meta-analysis assessing obliteration rates, outcomes, and complications of TVE for dAVFs. Our analysis highlights the higher (>90%) complete obliteration rates. Large prospective multicenter studies are needed to better define the utility of TVE for noncavernous dAVFs.

Mechanical thrombectomy in low Alberta Stroke Program Early Computed Tomographic Score: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Due to their poor natural history and lack in level-I evidence, patients with large vessel occlusion and large core infarcts (Alberta Stroke Program Early Computed Tomographic Score <6) have been excluded from receiving mechanical thrombectomy. This systematic review and meta-analysis seeks to summarize current evidence from published randomized controlled trials to compare the safety and efficacy of mechanical thrombectomy with optimal medical therapy in treating stroke patients with large core infarcts. METHODS: We searched PubMed and EMBASE for randomized controlled trials investigating the safety and efficacy of mechanical thrombectomy vs optimal medical therapy in patients presenting with large vessel occlusion and large infarcts. Basic demographic and comorbidities were assessed, and clinical outcomes were compared, including modified Rankin scale 0-3, and 0-2 at 3 months, symptomatic intracranial hemorrhage, decompressive hemicortectomy, and 90-day mortality. RESULTS: Three randomized controlled trials totaling 1011 patients (501 and 510 in the medical management and mechanical thrombectomy arm, respectively) were included. Patients undergoing mechanical thrombectomy had significantly higher odds of achieving better functional outcomes at 3 months: Modified Rankin scale 0-2 (OR = 3.05, 95% CI = 2.101-4.4021, p < 0.0001) and modified Rankin scale 0-3 (OR = 2.20, 95% CI = 1.67-2.89, p < 0.0001) as compared to those receiving optimal medical management. There were no differences between groups in 90-day mortality (OR = 0.93, 95% CI = 0.70-1.23, p = 0.60), symptomatic intracranial hemorrhage (OR = 1.89, 95% = CI 0.95-3.77, p = 0.07) or decompressive hemicraniectomy (OR = 1.25, 95% CI = 0.69-2.25, p = 0.46). CONCLUSION: Mechanical thrombectomy for patients with large infarcts is associated with improved functional outcomes and a similar safety profile compared to optimal medical management. Ongoing trials will help better refine the target population that benefits the most from treatment.

Early Termination versus Standard Regimen Duration of Dual Antiplatelet Therapy in Intracranial Aneurysm Patients Treated With Pipeline Embolization Device Flex With Shield Technology: Preliminary Experience of 3 U.S. Centers.

BACKGROUND: Pipeline Flex Embolization Device with Shield Technology (PED-Shield) is a third-generation flow diverter with reduced thromboembolic potential. However, safety profile and dual antiplatelet therapy (DAPT) recommendations with PED-Shield is not well -established. We aim to assess the safety and complication profile with early termination of DAPT with use of PED-Shield. METHODS: Databases of 3 high-volume cerebrovascular centers were retrospectively reviewed. We identified patients with unruptured and ruptured intracranial aneurysms treated with PED-Shield. Patient demographics, aneurysm characteristics, complications, and angiographic outcomes were extracted. All patients who had early termination of DAPT, defined as <180 days, as well as standard duration were included. RESULTS: A total of 37 patients, totaling 37 aneurysms, had early termination of DAPT and 24 patients with 24 aneurysms received standard duration (>180 days) of DAPT. There was no difference in pre-procedural DAPT regimens between the groups (P = 0.503). Following DAPT termination, o1ne major thromboembolic complication was observed in the early termination group while no major or minor thromboembolic or hemorrhagic complication was noted in the standard duration group. Time of angiographic follow-up was not statistically different (P = 0.063) between the early termination (343 days, interquartile range [IQR] 114-371 days) and the standard duration (175 days, IQR 111-224.5 days) groups. There were no statistically significant differences in complete aneurysm occlusion (P = 0.857), residual neck (P = 0.582), and aneurysm remnant (P = 0.352) rates between the groups on angiography. CONCLUSIONS: Early termination of DAPT proves safe after PED-Shield treatment of intracranial aneurysms with comparable complete occlusion rates.

Spatial Computing for preoperative planning and postoperative evaluation of single-position lateral approaches in spinal revision surgery.

Spatial computing (SC) in a surgical context offers reconstructed interactive four-dimensional models of radiological imaging. Preoperative and postoperative assessment with SC can offer more insight into personalized surgical approaches. Spine surgery has benefitted from the use of perioperative SC assessment. Herein, we describe the use of SC to perform a perioperative assessment of a revision spinal deformity surgery. A 79-year-old wheelchair-bound male presented to the neurosurgery clinic with a history of chronic lumbar pain associated with bilateral lower extremity weakness. His surgical history is significant for an L2-L5 lumbar decompression with posterior fixation 1 year prior. On examination, there were signs of thoracic myelopathy. Imaging revealed his previous instrumentation, pseudoarthrosis, and cord compression. We perform a two-staged operation to address the thoracic spinal cord compression and myelopathy, pseudoarthrosis, and malalignment with a lack of global spinal harmony. His imaging is driven by a spatial computing and SC environment and offers support for the diagnosis of his L2-3 and L4-5 pseudoarthrosis on the reconstructed SC-based computed tomography scan. SC enabled the assessment of the configuration of the psoas muscle and course of critical neurovascular structures in addition to graft sizing, trajectory and approach, evaluation of the configuration and durability of the anterior longitudinal ligament, and the overlying abdominal viscera. SC increases the familiarity of the patient's specific anatomy and enhances perioperative assessment. As such, SC can be used to preoperatively plan for spinal revision surgery.

Tension Pneumocranium Following Transsphenoidal Surgeries-A Case Report and Systematic Review of Literature with Analysis of Predisposing Factors and Treatment Regimens: Is Early Skull Base Repair Better than Conservative Treatment?

BACKGROUND: Conclusive evidence describing the outcomes following different treatment strategies for tension pneumocranium (TP) is lacking. Impact of predisposing conditions like multiple transnasal transsphenoidal (TNTS) procedures, intraoperative cerebrospinal fluid leak, obstructive sleep apnea, continuous positive airway pressure, violent coughing, nose blowing, positive pressure ventilation on TP outcomes is also unknown. METHODS: PubMed, Embase, Cochrane, and Google Scholar were searched for articles using Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Multivariate logistic regression analysis was done using STATA/ BE ver 17.0. RESULTS: Thirty-five studies with 49 cases of endoscopic TNTS surgeries were included. Tension pneumocephalus was seen in 77.5% (n = 38), tension pneumosella in 7 (14.28%), and tension pneumoventricle in 4 (8.16%). Nonfunctional pituitary adenomas (40.81%) were most common lesions associated with TP. The need of mechanical ventilation was significantly higher in patients who received conservative management (odds ratio, 1.34; confidence interval, 0.65-2.74) (P < 0.01). However, incidence of meningitis or mortality were not influenced by factors like age, gender, pathological diagnosis, initial conservative management or early skull base repair, use of adjuvant radiation, intraoperative cerebrospinal fluid leak, multiple TNTS explorations, or presence of precipitating factors. CONCLUSIONS: Nonfunctional pituitary adenomas were the most common lesions associated with TP. Multiple TNTS procedures did not increase incidence of meningitis or mortality. Conservative management increased the need for mechanical ventilation but did not worsen the mortality outcomes.

Gearing Up for the U.S. Medical Licensing Examination Step 1 Pass/Fail Transition, Evaluating the Role of Research Productivity as an Alternative During the Neurosurgical Residency Selection Process: An Overview.

Neurosurgery residency programs are the most competitive among the surgical specialties for applicants to match into. U.S. Medical Licensing Examination (USMLE) step 1 scores are staple and pivotal in narrowing down applicants for granting interviews and ranking in the match process. The upcoming transition from a numeric to binary step 1 scoring shifts the emphasis on using the status quo Step 2 Clinical Knowledge numeric scoring as the only objective measure. It can prove insubstantial for accurate assessment of competencies, further urging residency programs to widen their selection protocols to allow multiple assessments of competency. Research experience has consistently proved to result in higher successful match rates, and a positive correlation is seen with the number of research publications and Hirsch indices. However, with a predicted emphasis on research with the shift in scoring practices, these tools provide inadequate insight into authorship, contributions, type of publications, and community impact, warranting the need to include supplementary modifications, surrogates, or alternatives to such tools for a more comprehensive and equitable assessment of research. This study summarizes the role of research in the neurosurgical match process, describes nuances in research evaluation, and introduces novel Hirsch indices and additional strategies to address these nuances for equitable evaluation of research productions.

Intracranial giant tuberculoma: A 7-year institutional experience and literature review.

BACKGROUND: Intracranial tuberculomas are infrequent with a lower morbidity and mortality compared to tubercular meningitis. Giant intracranial tuberculomas are rarer but important differentials for intracranial space-occupying lesions causing focal neurological deficits depending on anatomical location and size. METHODS: Histopathologically confirmed giant intracranial tuberculomas selected based on institutional size criteria (<12 Years-old: ≥25 mm; 12-18 Years-old: ≥35 mm; ≥18 Years-old: ≥40 mm) were retrospectively reviewed and analyzed for clinical features, radiology, surgical management, and outcomes in patients admitted from 2015 to 2022. RESULTS: Ten patients were included (Males:Females = 3:7; Age: 8-68 Years, Average: 30.1 Years). Mean duration of symptoms was 2.84 months. Two patients demonstrated active systemic tuberculosis. Previous tubercular infections included pulmonary involvement in four, meningeal in three, and a cerebellar tuberculoma in one patient. Cerebrospinal fluid analysis in five patients demonstrated no tubercle bacilli. Seven lesions were supratentorial and three infratentorial. Giant tuberculomas demonstrated profound T2 hypointensity, sub-marginal T2 hyperintense crescents, and significant perilesional vasogenic edema. Craniotomy and excision were mainstay except in one case treated only with ventriculoperitoneal shunting. Three additional patients underwent ventriculoperitoneal shunting for hydrocephalus. One patient died from aspiration pneumonia and sepsis following a postoperative seizure. Anti-Tubercular Therapy (ATT) was advised for 18 months. Follow up ranged from 4 to 18 months. One patient was medically managed for ATT-induced hepatitis, hepatic encephalopathy, and coincidental paradoxical reaction. Remainder of patients showed complete resolution of symptomatology and absence of new symptoms till latest follow up. CONCLUSION: Clinical course of giant tuberculomas differ from non-giant variants in characteristic radiology, more intensive ATT, and possibility for partial debulking/excision.