Fixed- Versus Variable-Dose Prothrombin Complex Concentrate for the Emergent Reversal of Vitamin K Antagonists: A Systematic Review and Meta-Analysis.

OBJECTIVES: Four-factor prothrombin complex concentrate (4-PCC) is recommended for rapid reversal of vitamin K antagonists (VKAs) such as warfarin, yet optimal dosing remains uncertain. DATA SOURCES: A systematic review was conducted of PubMed, Embase, and Ovid MEDLINE (Wolters Kluwer) databases from January 2000 to August 2023 for clinical studies comparing fixed- vs. variable-dose 4-PCC for emergent VKA reversal with at least one reported clinical outcome. STUDY SELECTION: Abstracts and full texts were assessed independently and in duplicate by two reviewers. DATA EXTRACTION: Data were extracted independently and in duplicate by two reviewers using predefined extraction forms. DATA SYNTHESIS: The analysis comprised three randomized trials and 16 cohort studies comprising a total of 323 participants in randomized trials (161 in fixed dosage and 162 in variable dosage) and 1912 patients in cohort studies (858 in fixed-dose and 1054 in variable dose). Extracranial bleeding was the predominant indication, while intracranial hemorrhage varied. Overall, a fixed-dose regimen may be associated with a lower dose of 4-PCC and results in a reduction in 4-PCC administration time compared with a variable-dose regimen. A fixed-dose regimen also likely results in increased clinical hemostasis. While there is no clear difference between the two regimens in terms of achieving a goal international normalized ratio (INR) less than 2, a fixed-dose regimen is less likely to achieve a goal INR less than 1.5. High certainty evidence indicates that the fixed-dose regimen reduces both mortality and the occurrence of thromboembolic events. Additional subgroup analyses provides exploratory data to guide future studies. CONCLUSIONS: A fixed-dose regimen for 4-PCC administration provides benefits over a variable-dose regimen in terms of dose reduction, faster administration time, improved clinical hemostasis, and reduced mortality and thromboembolic events. Further studies are warranted to better refine the optimal fixed-dose regimen.

Bivalirudin as a substitute for heparin in neurointervention for patients with heparin-induced thrombocytopenia.

OBJECTIVES: Heparin-induced thrombocytopenia is a known complication of heparin exposure with potentially life-threatening sequelae. Direct thrombin inhibitors can be substituted for heparin in patients with heparin-induced thrombocytopenia that require anticoagulation. However, the use of direct thrombin inhibitors as a substitute for heparin has not been widely reported in the neuroendovascular literature. MATERIALS AND METHODS: Here we report the first use of the direct thrombin inhibitor bivalirudin in a neuroendovascular procedure as a substitute for heparin in a patient with a ruptured pseudoaneurysm and heparin-induced thrombocytopenia, and review the literature on the use of bivalirudin and argatroban for such patients. RESULTS: Bivalirudin was safely and effectively used in the case reported, with no thrombotic or hemorrhagic complications. Our literature review revealed a paucity of studies on the use of heparin alternatives, including bivalirudin, in neuroendovascular procedures in patients with heparin-induced thrombocytopenia. CONCLUSIONS: Heparin-induced thrombocytopenia is an important iatrogenic disease process in patients undergoing neuroendovascular procedures, and developing protocols to diagnose and manage heparin-induced thrombocytopenia is important for healthcare systems. While further research needs to be done to establish the full range of anticoagulation options to substitute for heparin, our case indicates bivalirudin as a potential candidate.

Ethical Considerations in Surgical Decompression for Stroke.

Stroke is a major cause of morbidity and mortality. Neurosurgical decompression is often considered for the treatment of malignant infarcts and intraparenchymal hemorrhages, but this treatment can be frought with ethical dilemmas. In this article, the authors outline the primary principles of bioethics and their application to stroke care, provide an overview of key ethical issues and special situations in the neurosurgical management of stroke, and highlight methods to improve ethical decision-making for patients with stroke. Understanding these ethical principles is essential for stroke care teams to deliver appropriate, timely, and ethical care to patients with stroke.

Endovascular Thrombectomy after Large-Vessel Ischemic Stroke: Utilization, Outcomes, and Readmissions across the United States.

Background Following publication of trials demonstrating the efficacy of thrombectomy, societal guidelines were revised in 2015 to recommend this procedure for large-vessel stroke. Purpose To evaluate real-world thrombectomy rates, adverse events, outcomes, and readmissions across the United States in the 2 years after large-scale adoption of thrombectomy for acute stroke. Materials and Methods In this retrospective study, the authors queried the National Inpatient Sample and Nationwide Readmissions Database for patients undergoing thrombectomy between 2016 and 2017. Thrombectomy rates were compared by using the χ2 test. Adjusted risk ratios (aRRs) were obtained for factors affecting routine discharge, mortality, and readmission by using multivariable Poisson regression with clustering at the hospital level. Results There were 290 460 admissions (mean age, 70.5 years ± 14.2 [standard deviation]; 148 620 women) for internal carotid or middle cerebral artery stroke; 30 835 (10.6%) of these patients underwent thrombectomy. Thrombectomy rates were lower in patients aged 90 years or older (1815 of 24 090 patients, 7.5%), Black patients (4280 of 43 365 patients, 9.9%), patients with the lowest income (8520 of 85 905 patients, 9.9%), and those treated in West South Central division hospitals (2695 of 34 355 patients, 7.8%) (P < .001 for all). The inpatient mortality rate was 12.1% (3740 of 30 835 patients), and 19.1% of patients (5900 of 30 835) were discharged to home. In adjusted analyses, routine discharge was less likely in patients aged 90 years or older (aRR: 0.12; 95% CI: 0.09, 0.16; P < .001) and octogenarians (aRR: 0.37; 95% CI: 0.33, 0.41; P < .001). Patients aged 90 years or older (aRR: 1.78; 95% CI: 1.48, 2.14; P < .001), octogenarians (aRR: 1.76; 95% CI: 1.51, 2.06; P < .001), Asians and/or Pacific Islanders (aRR: 1.21; 95% CI: 1.06, 1.39; P = .005), and those treated in teaching (aRR: 1.20; 95% CI: 1.07, 1.34; P = .001) or West South Central division (aRR: 1.35; 95% CI: 1.14, 1.60; P < .001) hospitals had a higher risk of death. Following discharge, 18.9% of patients (3449 of 18 274) were readmitted within 90 days. Conclusion Rates and outcomes of thrombectomy are affected by demographic, socioeconomic, and hospital-related factors. Fewer than one-fifth of patients are discharged to home, nearly one-fifth are readmitted within 90 days, and mortality and outcomes may be less favorable than in published trials. © RSNA, 2021 Online supplemental material is available for this article.

Prothrombin Complex Concentrate for Emergent Reversal of Intracranial Hemorrhage in Patients with Ventricular Assist Devices.

BACKGROUND: Intracranial hemorrhage (ICH) is a devastating complication for patients with ventricular assist devices (VADs). The safety of emergent anticoagulation reversal with four-factor prothrombin complex concentrate (PCC) and optimal timing of anticoagulation resumption are not clear. In addition, lactate dehydrogenase (LDH) is used as a biomarker for thromboembolic risk, but its utility in guiding anticoagulation management after reversal with PCC has not be described. METHODS: We retrospectively reviewed a consecutive series of patients with VADs presenting with ICH between 2014 and 2020 who received four-factor PCC for rapid anticoagulation reversal. We collected the timing of PCC administration, timing of resumption of anticoagulation, survival, occurrence of thromboembolic events, and LDH levels throughout hospitalization. RESULTS: We identified 16 ICH events in 14 patients with VADs treated with rapid anticoagulation reversal using four-factor PCC (11 intraparenchymal, 4 subdural, 1 subarachnoid hemorrhage). PCC was administered at a mean of 3.3 ± 0.3 h after imaging diagnosis of ICH. Overall mortality was 63%. Survivors had higher presenting Glasgow Coma Scale (median 15, interquartile range [IQR] 15-15 versus 14, IQR 8-14.7, P = 0.041). In all six instances where the patient survived, anticoagulation was resumed on average 9.16 ± 1.62 days after reversal. There were no thromboembolic events prior to resumption of anticoagulation. Three events occurred after anticoagulation resumption and within 3 months of reversal: VAD thrombosis in a patient with thrombosis at the time of reversal, ischemic stroke, and readmission for elevated LDH in the setting of subtherapeutic international normalized ratio. CONCLUSIONS: Our limited series found no thromboembolic complications immediately following anticoagulation reversal with PCC prior to resumption of anticoagulation. LDH trends may be useful to monitor thromboembolic risk after reversal.

Analysis of Mechanical Thrombectomy for Acute Ischemic Stroke on Nights and Weekends Versus Weekdays at Comprehensive Stroke Centers.

OBJECTIVE: The "weekend effect" has been shown to affect outcomes in acute ischemic stroke. We sought to compare metrics and outcomes of emergent stroke thrombectomy at three affiliated comprehensive stroke centers on weekdays versus nights/weekends for a three-year period beginning in 2015, when thrombectomy became common practice for large vessel occlusion acute ischemic stroke. METHODS: We performed a retrospective analysis of all stroke thrombectomy patients treated from 2015 to 2018 to compare standard thrombectomy metrics and outcomes in patients presenting during weekdays or nights/weekends. RESULTS: Two hundred-sixteen mechanical thrombectomy cases were evaluated, with 50.9% of patients presenting on weekdays and 49.1% presenting on nights/weekends. There were no statistical differences in baseline characteristics in demographics, stroke risk factors, or stroke severity, but patients presenting on nights/weekends had longer times from last known normal to presentation (130 versus 72.5 minutes, p=0.03). Door-to-groin times were delayed in patients presenting on nights/weekends compared to weekdays (median 104.5 versus 86 minutes, respectively; p=0.007) but groin-to-reperfusion times were similar (51.5 versus 48 minutes, respectively; p=0.4). Successful reperfusion was similar in both groups (90.6% nights/weekends versus 90% weekdays; p=1.0) as were the incidence of symptomatic intracerebral hemorrhage (10.4% nights/weekend versus 7.3% weekdays; p=0.48) and 90-day good functional outcomes based on the modified Rankin Scale did not differ between the two groups in a shift analysis (p=0.545). CONCLUSIONS: Despite delays in door-to-groin puncture times in acute ischemic stroke patients presenting on nights/weekends compared to weekdays, we did not identify significant differences in successful reperfusion or functional outcomes in this cohort. Further studies are warranted to continue to evaluate differences in stroke care on nights/weekends versus weekdays.

Magnesium and Risk of Bleeding Complications From Ventriculostomy Insertion.

BACKGROUND AND PURPOSE: Hemorrhages are a serious complication of brain surgery, and magnesium has shown hemostatic properties in hemorrhagic stroke and non-neurological surgeries. External ventricular drain (EVD) insertion is an advantageous model of emergency neurosurgical hemorrhage risk because it is common, standardized, and the operator is blinded to the outcome during the procedure. We tested the hypothesis that low magnesium is associated with risk of hemorrhagic complications from EVD insertion. METHODS: Patients with spontaneous intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage were enrolled in a prospective, observational study. Demographic and clinical variables were prospectively recorded, including serum magnesium measurements. Catheter tract hemorrhage (CTH) was measured on postoperative head computed tomography within 48 hours of EVD insertion. RESULTS: We observed 50 CTH among 327 EVD procedures (15.3%) distributed similarly among intracerebral hemorrhage (21/116 [18.1%]) and subarachnoid hemorrhage (29/211 [13.7%]). Magnesium was lower in patients with CTH compared with those without (median 1.8 versus 2.0 mg/dL, P<0.0001). Higher magnesium was associated with lower odds of CTH (odds ratio 0.67 per 0.1 mg/dL magnesium [95% CI, 0.56-0.78], P<0.0001) after adjustment for other risk factors, with similar effect in the intracerebral hemorrhage and subarachnoid hemorrhage subgroups. Preprocedural increase in magnesium (odds ratio 0.68 [0.52-0.85]) and dose of preprocedural magnesium sulfate (odds ratio 0.67 [0.40-0.97]) were associated with reduced CTH risk after adjustment for initial magnesium and other risk factors. CONCLUSIONS: Lower magnesium at the time of EVD insertion was an independent predictor of hemorrhagic complications. Baseline risk was attenuated by preprocedural increases in magnesium, suggesting a therapeutic opportunity.

Spinal neurovascular complications with anterior thoracolumbar spine surgery: a systematic review and review of thoracolumbar vascular anatomy.

OBJECTIVE: Spinal cord infarction due to interruption of the spinal vascular supply during anterior thoracolumbar surgery is a rare but devastating complication. Here, the authors sought to summarize the data on this complication in terms of its incidence, risk factors, and operative considerations. They also sought to summarize the relevant spinal vascular anatomy. METHODS: They performed a systematic literature review of the PubMed, Scopus, and Embase databases to identify reports of spinal cord vascular injury related to anterior thoracolumbar spine procedures as well as operative adjuncts and considerations related to management of the segmental artery ligation during such anterior procedures. Titles and abstracts were screened, and studies meeting inclusion criteria were reviewed in full. RESULTS: Of 1200 articles identified on the initial screening, 16 met the inclusion criteria and consisted of 2 prospective cohort studies, 10 retrospective cohort studies, and 4 case reports. Four studies reported on the incidence of spinal cord ischemia with anterior thoracolumbar surgery, which ranged from 0% to 0.75%. Eight studies presented patient-level data for 13 cases of spinal cord ischemia after anterior thoracolumbar spine surgery. Proposed risk factors for vasculogenic spinal injury with anterior thoracolumbar surgery included hyperkyphosis, prior spinal deformity surgery, combined anterior-posterior procedures, left-sided approaches, operating on the concavity side of a scoliotic curve, and intra- or postoperative hypotension. In addition, eight studies analyzed operative considerations to reduce spinal cord ischemic complications in anterior thoracolumbar surgery, including intraoperative neuromonitoring and preoperative spinal angiography. CONCLUSIONS: While spinal cord infarction related to anterior thoracolumbar surgery is rare, it warrants proper consideration in the pre-, intra-, and postoperative periods. The spine surgeon must be aware of the relevant risk factors as well as the pre- and intraoperative adjuncts that can minimize these risks. Most importantly, an understanding of the relevant spinal vascular anatomy is critical to minimizing the risks associated with anterior thoracolumbar spine surgery.

Overview of medical malpractice in neurosurgery.

Annually, 20% of all practicing neurosurgeons in the United States are faced with medical malpractice litigation. The average indemnity paid in a closed neurosurgical civil claim is $439,146, the highest of all medical specialties. The majority of claims result from dissatisfaction following spinal surgery, although claims after cranial surgery tend to be costlier. On a societal scale, the increasing prevalence of medical malpractice claims is a catalyst for the practice of defensive medicine, resulting in record-level healthcare costs. Outside of the obvious financial strains, malpractice claims have also been linked to professional disenchantment and career changes for afflicted physicians. Unfortunately, neurosurgical residents receive minimal practical education regarding these matters and are often unprepared and vulnerable to these setbacks in the earlier stages of their careers. In this article, the authors aim to provide neurosurgical residents and junior attendings with an introductory guide to the fundamentals of medical malpractice lawsuits and the implications for neurosurgeons as an adjunct to more formal residency education.

Standardized Evaluation of Cerebral Arteriovenous Malformations Using Flow Distribution Network Graphs and Dual-venc 4D Flow MRI.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) are pathological connections between arteries and veins. Dual-venc 4D flow MRI, an extended 4D flow MRI method with improved velocity dynamic range, provides time-resolved 3D cerebral hemodynamics. PURPOSE: To optimize dual-venc 4D flow imaging parameters for AVM; to assess the relationship between spatial resolution, acceleration, and flow quantification accuracy; and to introduce and apply the flow distribution network graph (FDNG) paradigm for storing and analyzing complex neurovascular 4D flow data. STUDY TYPE: Retrospective cohort study. SUBJECTS/PHANTOM: Scans were performed in a specialized flow phantom: 26 healthy subjects (age 41 ± 17 years) and five AVM patients (age 27-68 years). FIELD STRENGTH/SEQUENCE: Dual-venc 4D flow with varying spatial resolution and acceleration factors were performed at 3T field strength. ASSESSMENT: Quantification accuracy was assessed in vitro by direct comparison to measured flow. FDNGs were used to quantify and compare flow, peak velocity (PV), and pulsatility index (PI) between healthy controls with various Circle of Willis (CoW) anatomy and AVM patients. STATISTICAL TESTS: In vitro measurements were compared to ground truth with Student's t-test. In vivo groups were compared with Wilcoxon rank-sum test and Kruskal-Wallis test. RESULTS: Flow was overestimated in all in vitro experiments, by an average 7.1 ± 1.4% for all measurement conditions. Error in flow measurement was significantly correlated with number of voxels across the channel (P = 3.11 × 10-28 ) but not with acceleration factor (P = 0.74). For the venous-arterial PV and PI ratios, a significant difference was found between AVM nidal and extranidal circulation (P = 0.008 and 0.05, respectively), and between AVM nidal and healthy control circulation (P = 0.005 and 0.003, respectively). DATA CONCLUSION: Dual-venc 4D flow MRI and standardized FDNG analysis might be feasible in clinical applications. Venous-arterial ratios of PV and PI are proposed as network-based biomarkers characterizing AVM nidal hemodynamics. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;50:1718-1730.

Prophylactic Seizure Medication and Health-Related Quality of Life After Intracerebral Hemorrhage.

OBJECTIVES: Prophylactic levetiracetam is currently used in ~40% of patients with intracerebral hemorrhage, and the potential impact of levetircetam on health-related quality of life is unknown. We tested the hypothesis that prophylactic levetiracetam is independently associated with differences in cognitive function health-related quality of life. DESIGN: Patients with intracerebral hemorrhage were enrolled in a prospective cohort study. We performed mixed models for T-scores of health-related quality of life, referenced to the U.S. population at 50 ± 10, accounting for severity of injury and time to follow-up. SETTING: Academic medical center. PATIENTS: One-hundred forty-two survivors of intracerebral hemorrhage. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: T-scores of Neuro-Quality of Life Cognitive Function v2.0 was the primary outcome, whereas Neuro-Quality of Life Mobility v1.0 and modified Rankin Scale (a global functional scale) were secondary measures. We prospectively documented if prophylactic levetiracetam was administered and retrieved administration data from the electronic health record. Patients who received prophylactic levetiracetam had worse cognitive function health-related quality of life (T-score 5.1 points lower; p = 0.01) after adjustment for age (p = 0.3), National Institutes of Health Stroke Scale (p < 0.000001), lobar hematoma (p = 0.9), and time of assessment; statistical models controlling for prophylactic levetiracetam and the Intracerebral Hemorrhage Score, a global measure of intracerebral hemorrhage severity, yielded similar results. Lower T-scores of cognitive function health-related quality of life at 3 months were correlated with more total levetiracetam dosage (p = 0.01) and more administered doses of levetiracetam in the hospital (p = 0.03). Patients who received prophylactic levetiracetam were more likely to have a lobar hematoma (27/38 vs 19/104; p < 0.001), undergo electroencephalography monitoring (15/38 vs 21/104; p = 0.02), but not more likely to have clinical seizures (4/38 vs 7/104; p = 0.5). Levetiracetam was not independently associated with the modified Rankin Scale scores or mobility health-related quality of life (p > 0.1). CONCLUSIONS: Prophylactic levetiracetam was independently associated with lower cognitive function health-related quality of life at follow-up after intracerebral hemorrhage.

Applying Craniofacial Principles to Neurosurgical Exposures in Cerebrovascular Aneurysm Repair.

The subspecialty of craniofacial surgery emphasizes skeletal exposure, preservation of critical structures, and provision of a superior cosmetic result. In recent decades, an emphasis on minimally invasive neurosurgical exposure has paved the way for increased collaboration between neurosurgeons and craniofacial surgeons.The 1990s saw the growing popularity of an eyebrow incision for orbital roof craniotomies in neurosurgery to address lesions in the anterior skull base. Disadvantages of this approach included conspicuous scarring above the brow skin, risk of injury to the frontal branch of the facial nerve, and numbness from supraorbital or supratrochlear nerve transection.A transpalpebral approach was first described in 2008 in the neurosurgical literature. An approach familiar to the craniofacial surgeon, transpalpebral exposure is used for zygomaticomaxillary complex fractures as well as aesthetic brow and periorbital surgery.In conjunction with neurosurgery, the authors have applied craniofacial principles to address the major pitfalls of the transpalpebral craniotomy. The authors present their patient series experience. Hopefully, in the future, other institutions will have increased collaboration between craniofacial surgeons and neurosurgeons.

Cavernous and inferior petrosal sinus sampling and dynamic magnetic resonance imaging in the preoperative evaluation of Cushing's disease.

The surgical management of Cushing's disease is often complicated by difficulties detecting corticotropic adenomas. Various diagnostic modalities are used when conventional magnetic resonance imaging (MRI) is negative or inconclusive. We sought to analyze our use of two such modalities in the surgical management of Cushing's disease: (1) cavernous/inferior petrosal sinus sampling (central venous sampling, CVS) for adrenocorticotropic hormone and (2) dynamic MRI (dMRI). We conducted a single-center, retrospective review of all patients with Cushing's disease treated by a single neurosurgeon with endonasal transsphenoidal surgery. Accuracy of adenoma localization with CVS and dMRI was analyzed. Ninety-one consecutive patients were included. Pathology confirmed an adenoma in 66. Preoperative dMRI and CVS were performed in 40 and 37 patients, respectively, with 20 undergoing both studies. Surgical pathology was positive for adenoma in 31 dMRI patients, 25 CVS patients, and 13 who underwent both. Among patients with pathology confirming an adenoma, dMRI identified a lesion in 96.8% and correctly lateralized the lesion in 89.7%, while CVS correctly lateralized in 52.2-65.2% (depending on location of sampling). Among patients with both studies, dMRI and CVS correctly lateralized in 76.9 and 61.5-69.2%, respectively. Accuracy of CVS improved if only patients with symmetric venous drainage were considered. In this mixed population of Cushing's disease patients, dMRI was more accurate than CVS at localizing adenomas, supporting the use of advance MRI techniques in the work-up of Cushing's disease. CVS, however, remains an important tool in the workup of Cushing's syndrome.

Angiographic features help predict outcome after stereotactic radiosurgery for the treatment of pediatric arteriovenous malformations.

PURPOSE: Arteriovenous malformations (AVMs) are a frequent cause of hemorrhagic stroke in children. Stereotactic radiosurgery (SRS) is an established treatment for these lesions, particularly those that are surgically inaccessible. Because only complete AVM obliteration is believed to protect against the future risk of hemorrhage, identifying lesion characteristics that predict response to therapy is an important objective. The goal of this study is to evaluate the influence of angiographic features of AVMs on the rate of obliteration following treatment with SRS. METHODS: This is a retrospective cohort study of pediatric patients (age ≤18 years) treated with Gamma Knife SRS for cerebral AVMs between 2000 and 2012. Detailed angiographic data at the time of initial angiographic evaluation were prospectively recorded by experienced neurointerventional radiologists. The primary outcome was the rate of obliteration on a 3-year follow-up angiogram. RESULTS: We identified 42 pediatric patients treated with SRS for cerebral AVMs. Twenty-seven patients completed 3-year angiographic follow-ups. Complete obliteration was seen in 30%, partial response in 67%, and no response in 4%. Higher SRS dose was associated with complete obliteration. Larger AVM diameter, presence of multiple draining veins, and presence of multiple draining veins reaching a sinus were associated with partial response. In this small cohort, diffuse AVM borders, presence of aneurysm, and pre-SRS embolization were not associated with obliteration. CONCLUSIONS: Our study identifies AVMs in the pediatric population with a nidus diameter of <2.5 cm and a solitary draining vein as the most likely to undergo complete obliteration after SRS treatment.

Curing arteriovenous malformations using embolization.

Endovascular embolization is typically reserved as an adjuvant therapy in the management of cerebral arteriovenous malformations (AVMs), either for preoperative devascularization or preradiosurgical volume reduction. Curative embolization plays a limited role in AVM treatment but several studies have shown that it is possible, especially with later-generation liquid embolic agents. Given the complexity of AVM anatomy and the recent controversies over the role of any intervention in AVM management, it is critical that the cerebrovascular community better define the indications of each treatment modality to provide quality AVM management. In this review, the authors evaluate the role of curative AVM embolization. Important considerations in the feasibility of curative AVM embolization include whether it can be performed reliably and safely, and whether it is a durable cure. Studies over the past 20 years have begun to define the anatomical factors that are amenable to complete endovascular occlusion, including size, feeding artery anatomy, AVM morphology, and endovascular accessibility. More recent studies have shown that highly selected patients with AVMs can be treated with curative intent, leading to occlusion rates as high as 100% of such prospectively identified lesions with minimal morbidity. Advances in endovascular technology and techniques that support the efficacy and safety of curative embolization are discussed, as is the importance of superselective diagnostic angiography. Finally, the durability of curative embolization is analyzed. Overall, while still unproven, endovascular embolization has the potential to be a safe, effective, and durable curative treatment for select AVMs, broadening the armamentarium with which one can treat this disease.

Charlson Comorbidity Index and Frailty as Predictors of Resolution Following Middle Meningeal Artery Embolization for Chronic Subdural Hematoma.

BACKGROUND: Research on variables associated with chronic subdural hematoma (cSDH) resolution following middle meningeal artery embolization (MMAE) is limited. This study investigated the clinical utility of age-adjusted Charlson Comorbidity Index (ACCI) and modified 5-item Frailty Index (mFI - 5) for predicting cSDH resolution following MMAE. METHODS: We identified patients who underwent MMAE at our institution between January 2018 and December 2022, with at least 20 days of follow-up and one radiographic follow-up study. Patient demographics, characteristics, and outcomes were collected. Complete resolution was defined as absence of subdural collections on CT-scan at last follow-up. Nonage adjusted CCI (CCI), ACCI, and mFI - 5 scores were calculated. Univariate and multivariable logistic regression analyzed the relationship between cSDH resolution and variables. A receiver operating characteristic (ROC) curve established the utility of ACCI and mFI - 5 in predicting hematoma resolution. RESULTS: The study included 85 MMAE procedures. In univariate analysis, patients without resolution were older, had higher CCI, higher ACCI, higher mFI - 5, and were more likely to have diabetes mellitus. In multivarible analysis, CCI (OR: 0.66, 95% CI: 0.48, 0.91) was independently associated with resolution controlling for age and antithrombotic resumption. The area under the ROC (AUROC) curve was 0.75 (95% CI: 0.65-0.85) for ACCI and 0.64 (95% CI: 0.52-0.76) for mFI - 5. The optimal cutoffs for predicting resolution were ACCI ≥5 (sensitivity = 0.63, specificity = 0.77), and mFI - 5 > 0 (sensitivity = 0.84, specificity = 0.43). CONCLUSIONS: ACCI and mFI - 5 moderately predict MMAE resolution and may aid in medical decision-making.

Radionuclide shuntography for cerebrospinal fluid shunt flow evaluation in adults.

OBJECTIVE: Radionuclide shuntography (RS) performed using 99mTc-DTPA injected into the reservoir of CSF shunts enables evaluation of CSF flow for suspected shunt malfunctions. The goal of this study was to report the authors' institutional experience with RS and evaluate its utility and associated complications. METHODS: The authors retrospectively reviewed all RS studies performed between November 2003 and June 2022. Patients with shunted hydrocephalus who were ≥ 18 years of age were included. Patients undergoing RS for evaluation of Ommaya reservoirs were excluded. Demographics, hydrocephalus etiology, presenting symptoms, study results, subsequent management, complications, and intraoperative diagnoses were recorded. Chi-square tests were reported for categorical variables and standard 2 × 2 contingency methods were used for sensitivity/specificity analysis. RESULTS: The authors identified 211 RS procedures performed in 142 patients. The mean age at procedure was 55.6 ± 20.9 years (mean ± SD). Normal pressure hydrocephalus was the most common hydrocephalus etiology (37.0%), followed by congenital malformations (26.1%) and idiopathic intracranial hypertension (15.6%). Successful radionuclide injection was achieved in 207 studies (98.1%). Shunt patency was confirmed in 63.8% of successful injections, whereas malfunction was demonstrated in 27.1% and abnormally slow flow was seen in 9.2%. RS studies demonstrating shunt malfunction were more likely to result in subsequent revisions than were studies showing patency (86.6% vs 2.9%; p < 0.0001). The overall sensitivity and specificity of RS for detecting shunt malfunction was 92.3% and 96.2%, respectively. The median follow-up time was 29 months, with 151 cases having ≥ 6 months of follow-up. There were no complications or infections attributable to RS in this cohort. CONCLUSIONS: RS is a useful and safe tool in the workup of shunt malfunction.

Background Subtraction Angiography with Deep Learning Using Multi-frame Spatiotemporal Angiographic Input.

Catheter Digital Subtraction Angiography (DSA) is markedly degraded by all voluntary, respiratory, or cardiac motion artifact that occurs during the exam acquisition. Prior efforts directed toward improving DSA images with machine learning have focused on extracting vessels from individual, isolated 2D angiographic frames. In this work, we introduce improved 2D + t deep learning models that leverage the rich temporal information in angiographic timeseries. A total of 516 cerebral angiograms were collected with 8784 individual series. We utilized feature-based computer vision algorithms to separate the database into "motionless" and "motion-degraded" subsets. Motion measured from the "motion degraded" category was then used to create a realistic, but synthetic, motion-augmented dataset suitable for training 2D U-Net, 3D U-Net, SegResNet, and UNETR models. Quantitative results on a hold-out test set demonstrate that the 3D U-Net outperforms competing 2D U-Net architectures, with substantially reduced motion artifacts when compared to DSA. In comparison to single-frame 2D U-Net, the 3D U-Net utilizing 16 input frames achieves a reduced RMSE (35.77 ± 15.02 vs 23.14 ± 9.56, p < 0.0001; mean ± std dev) and an improved Multi-Scale SSIM (0.86 ± 0.08 vs 0.93 ± 0.05, p < 0.0001). The 3D U-Net also performs favorably in comparison to alternative convolutional and transformer-based architectures (U-Net RMSE 23.20 ± 7.55 vs SegResNet 23.99 ± 7.81, p < 0.0001, and UNETR 25.42 ± 7.79, p < 0.0001, mean ± std dev). These results demonstrate that multi-frame temporal information can boost performance of motion-resistant Background Subtraction Deep Learning algorithms, and we have presented a neuroangiography domain-specific synthetic affine motion augmentation pipeline that can be utilized to generate suitable datasets for supervised training of 3D (2d + t) architectures.

Navigating the Neurosurgery Match Process: Insights from the National Resident Matching Program - Program Director Surveys.

OBJECTIVE: Neurosurgery is one of the most competitive specialties and navigating the match process is often challenging for aspiring applicants. Here, we analyze insights from the National Resident Matching Program (NRMP) Program Director Surveys, illustrating evolving trends in applicant selection for interviews and for the ranking process, and providing a comparison with other specialties. METHODS: We evaluated seven surveys administered from 2012 to 2022. Six biennial surveys reported on factors influencing interview and ranking processes, while all seven surveys included data about the program director (PD)'s attitude towards USMLE test scores. RESULTS: The response rate of PDs decreased over the years. The most cited for interviews included specialty-specific recommendation letters (95%), USMLE Step 1 scores (91%), and interest in research (78%). A recent decline in emphasis on USMLE Step 1 scores coincided with a growing reliance on USMLE Step 2 scores. Award in basic science held significant esteem to a subset of programs. Personal characteristics dominated for ranking, with faculty interaction (89%), interpersonal skills (89%), and house staff interaction (85%) being the most important. Yet, PDs reported a difficulty in assessing interpersonal skills through virtual interviews. CONCLUSION: Our analysis revealed the pervasive importance of specialized endorsements and academic achievements when screening applicants for the interview process. A shift in emphasis towards the USMLE step 2 became apparent. Personal characteristics, on the other hand, seemed crucial to make a match and rank high among the pool of interviewed applicants. We uncovered difficulties in assessing these characteristics through virtual interviews.