Cardiac patterns for differentiation of neurogenic stunned myocardium in aneurysmal subarachnoid hemorrhage versus acute ischemic stroke.

AIMS: Neurogenic stunned myocardium (NSM) has heterogeneous presentations for acute ischemic stroke (AIS) and aneurysmal subarachnoid hemorrhage (SAH). We sought to better define NSM and differences between AIS and SAH by evaluating individual left ventricular (LV) functional patterns by speckle tracking echocardiography (STE). METHODS: We evaluated consecutive patients with SAH and AIS. Via STE, LV longitudinal strain (LS) values of basal, mid, and apical segments were averaged and compared. Different multivariable logistic regression models were created by defining stroke subtype (SAH or AIS) and functional outcome as dependent variables. RESULTS: One hundred thirty-four patients with SAH and AIS were identified. Univariable analyses using the chi-squared test and independent samples t-test identified demographic variables and global and regional LS segments with significant differences. In multivariable logistic regression analysis, when comparing AIS to SAH, AIS was associated with older age (OR 1.07, 95% CI 1.02-1.13, p = 0.01), poor clinical condition on admission (OR 7.74, 95% CI 2.33-25.71, p < 0.001), decreased likelihood of elevated admission serum troponin (OR .09, 95% CI .02-.35, p < 0.001), and worse LS basal segments (OR 1.18, 95% CI 1.02-1.37, p = 0.03). CONCLUSION: In patients with neurogenic stunned myocardium, significantly impaired LV contraction by LS basal segments was found in patients with AIS but not with SAH. Individual LV segments in our combined SAH and AIS population were also not associated with clinical outcomes. Our findings suggest that strain echocardiography may identify subtle forms of NSM and help differentiate the NSM pathophysiology in SAH and AIS.

Middle meningeal artery embolization with subdural evacuating port system for primary management of chronic subdural hematomas.

Optimal treatment for chronic subdural hematomas remains controversial and perioperative risks and comorbidities may affect management strategies. Minimally invasive procedures are emerging as alternatives to the standard operative treatments. We evaluate our experience with middle meningeal artery (MMA) embolization combined with Subdural Evacuating Port System (SEPS) placement as a first-line treatment for patients with cSDH. A single institution retrospective review was performed of all patients undergoing intervention. Patients were stratified by treatment with MMA embolization and SEPS placement, MMA embolization and surgery, SEPS placement only, and surgery only for cSDH from 2017 to 2020, and cohorts were compared against each other. Patients treated with MMA/SEPS were more likely to be older, be on anticoagulation, have significant comorbidities, have shorter length of stay, and less likely to have symptomatic recurrence compared to SEPS only cohort. Thus, MMA/SEPS appears to be a safe and equally effective minimally invasive treatment for cSDH patients with significant comorbidities who are poor surgical candidates.

Early Fevers and Elevated Neutrophil-to-Lymphocyte Ratio are Associated with Repeat Endovascular Interventions for Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Patients with aneurysmal subarachnoid hemorrhage (aSAH) may develop refractory arterial cerebral vasospasm requiring multiple endovascular interventions. The aim of our study is to evaluate variables associated with need for repeat endovascular treatments in refractory vasospasm and to identify differences in outcomes following one versus multiple treatments. METHODS: We retrospectively reviewed patients treated for aSAH between 2017 and 2020 at two tertiary care centers. We included patients who underwent treatment (intraarterial infusion of vasodilatory agents or mechanical angioplasty) for radiographically diagnosed vasospasm in our analysis. Patients were divided into those who underwent single treatment versus those who underwent multiple endovascular treatments for vasospasm. RESULTS: Of the total 418 patients with aSAH, 151 (45.9%) underwent endovascular intervention for vasospasm. Of 151 patients, 95 (62.9%) underwent a single treatment and 56 (37.1%) underwent two or more treatments. Patients were more likely to undergo multiple endovascular treatments if they had a Hunt-Hess score > 2 (odds ratio [OR] 5.10 [95% confidence interval (CI) 1.82-15.84]; p = 0.003), a neutrophil-to-lymphocyte ratio > 8.0 (OR 3.19 [95% CI 1.40-7.62]; p = 0.028), and more than two fevers within the first 5 days of admission (OR 7.03 [95% CI 2.68-20.94]; p < 0.001). Patients with multiple treatments had poorer outcomes, including increased length of stay, delayed cerebral ischemia, in-hospital complications, and higher modified Rankin scores at discharge. CONCLUSIONS: A Hunt-Hess score > 2, a neutrophil-to-lymphocyte ratio > 8.0, and early fevers may be predictive of need for multiple endovascular interventions in refractory cerebral vasospasm after aSAH. These patients have poorer functional outcomes at discharge and higher rates of in-hospital complications.

Abnormal neurological pupil index is associated with malignant cerebral edema after mechanical thrombectomy in large vessel occlusion patients.

BACKGROUND AND OBJECTIVES: Malignant cerebral edema (MCE) is a feared complication in patients suffering from large vessel occlusion. Variables associated with the development of MCE have not been clearly elucidated. Use of pupillometry and the neurological pupil index (NPi) as an objective measure in patients undergoing mechanical thrombectomy (MT) has not been explored. We aim to evaluate variables significantly associated with MCE in patients that undergo MT and hypothesize that abnormal NPi is associated with MCE in this population. METHODS: A retrospective analysis of patients with acute ischemic stroke who had undergone MT at our institution between 2017 and 2020 was performed. Baseline and outcome variables were collected, including NPi values from pupillometry readings of patients within 72 h after the MT. Patients were divided into two groups: MCE versus non-MCE group. A univariate and multivariate analysis was performed. RESULTS: Of 284 acute ischemic stroke patients, 64 (22.5%) developed MCE. Mean admission glucose (137 vs. 173; p < 0.0001), NIHSS on admission (17 vs. 24; p < 0.01), infarct core volume (27.9 vs. 17.9 mL; p = 0.0036), TICI score (p = 0.001), and number of passes (2.9 vs. 1.8; p < 0.0001) were significantly different between the groups. Pupillometry data was present for 64 patients (22.5%). Upon multivariate analysis, abnormal ipsilateral NPi (OR 21.80 95% CI 3.32-286.4; p = 0.007) and hemorrhagic conversion were independently associated with MCE. CONCLUSION: Abnormal NPi and hemorrhagic conversion are significantly associated with MCE in patients following MT. Further investigation is warranted to better define an association between NPi and patient outcomes in this patient population.

Outcomes of patients with nonepileptic transient neurologic symptoms after subdural hematoma evacuation.

BACKGROUND: Patients undergoing a subdural hematoma (SDH) evacuation can experience transient neurological symptoms (TNS) postoperatively. Electroencephalography (EEG) is used to rule out seizures. We aim to characterize patients with TNS and negative epileptiform activity on EEG and compare them to those with positive epileptiform EEG findings. METHODS: We performed a retrospective study of adult patients who underwent EEG for evaluation of TNS after undergoing SDH evacuation. Patients were stratified based on SDH type (acute and non-acute) and whether or not their EEG demonstrated positive epileptiform activity. A multivariate analysis was performed to identify predictors of negative EEG findings. RESULTS: One hundred twenty-nine SDH patients were included (45 (34.9%) acute; 84 (65.1%) non-acute). Overall, 45 (24 acute and 21 non-acute SDH patients) had positive epileptiform EEG findings, and 84 (21 acute and 63 non-acute SDH patients) had a negative EEG. Acute and non-acute SDH patients with positive EEG findings were more likely to suffer from greater than five episodes of TNS, impaired awareness, and motor symptoms, while the negative EEG group was more likely to suffer from negative symptoms. Non-acute SDH patients with positive EEG had longer mean ICU stays (14.6 vs. 7.2; p = 0.005). Both acute and non-acute SDH-positive EEG patients had worse disposition upon discharge (p < 0.05), worse modified Rankin score at discharge (p < 0.05), and 3-month follow-up (p < 0.05) and were more likely to be discharged on more than one antiepileptic drug (p < 0.001). CONCLUSION: Postoperative acute and non-acute SDH patients with TNS and negative EEG results are likely to have a favorable clinical picture. This distinction is therapeutically and prognostically important as these patients may not respond to typical antiepileptic drugs and they have better functional outcomes.

Management of Intracranial Hemorrhage in Patients with a Left Ventricular Assist Device: A Systematic Review and Meta-Analysis.

BACKGROUND: Intracranial hemorrhage (ICH) has been reported to occur in up to 23% of patients with left ventricular assist devices (LVADs). Currently, limited data exists to guide neurosurgical management strategies to optimize outcomes in patients with an LVAD who develop ICH. METHODS: A systematic review and meta-analysis of the literature was performed to evaluate the mortality rate in these patients following medical and/or surgical management and to evaluate antithrombotic reversal and resumption strategies after hemorrhage. RESULTS: 17 studies reporting on 3869 LVAD patients and 545 intracranial hemorrhages spanning investigative periods from 1996 to 2019 were included. The rate of ICH in LVAD patients was 10.6% (411/3869) with 58.6% (231/394) being intraparenchymal hemorrhage (IPH), 23.6% (93/394) subarachnoid hemorrhage (SAH), and 15.5% (61/394) subdural hemorrhage (SDH). Total mortality rates for surgical management 65.6% (40/61) differed from medical management at 45.2% (109/241). There was an increased relative risk of mortality (RR=1.45, 95% CI: 1.10-1.91, p = 0.01) for ICH patients undergoing surgical intervention. The hemorrhage subtype most frequently managed with anticoagulation reversal was IPH 81.8% (63/77), followed by SDH 52.2% (12/23), and SAH 39.1% (18/46). Mean number of days until antithrombotic resumption ranged from 6 to 10.5 days. CONCLUSION: Outcomes remain poor, specifically for those undergoing surgery. As experience with this population increases, prospective studies are warranted to contribute to management and prognostication .

Admission Neutrophil to Lymphocyte Ratio for Predicting Outcome in Subarachnoid Hemorrhage.

PURPOSE: We sought to evaluate the relationship between admission neutrophil-to-lymphocyte ratio (NLR) and functional outcome in aneurysmal subarachnoid hemorrhage (aSAH) patients. MATERIAL AND METHODS: Consecutive patients with aSAH were treated at two tertiary stroke centers during a five-year period. Functional outcome was defined as discharge modified Rankin score dichotomized at scores 0-2 (good) vs. 3-6 (poor). RESULTS: 474 aSAH patients were evaluated with a mean NLR 8.6 (SD 8.3). In multivariable logistic regression analysis, poor functional outcome was independently associated with higher NLR, older age, poorer clinical status on admission, prehospital statin use, and vasospasm. Increasing NLR analyzed as a continuous variable was independently associated with higher odds of poor functional outcome (OR 1.03, 95%CI 1.00-1.07, p=0.05) after adjustment for potential confounders. When dichotomized using ROC curve analysis, a threshold NLR value of greater than 6.48 was independently associated with higher odds of poor functional outcome (OR 1.71, 95%CI 1.07-2.74, p=0.03) after adjustment for potential confounders. CONCLUSIONS: Higher admission NLR is an independent predictor for poor functional outcome at discharge in aSAH patients. The evaluation of anti-inflammatory targets in the future may allow for improved functional outcome after aSAH.

Manuka Honey: Feasibility and Safety in Postoperative Neurosurgical Wound Care.

OBJECTIVE: To date, no reports have been published on active Leptospermum manuka honey (ALH) feasibility as a postoperative topical wound supplement in neurosurgical patients. The objective of the study is to present the authors' initial experience with using ALH in postoperative neurosurgical patients. METHODS: A single-surgeon retrospective case series review of cranial and spinal operations between 2018 and 2020 was performed in patients with nonhealing wounds or wounds deemed "at risk" as defined by grade 1 Sandy surgical wound dehiscence grading classification. An ALH gel or ointment was applied to these incisions once a day for 2 to 4 weeks. Patients were followed up in the clinic every 2 weeks until incisions had healed. RESULTS: Twenty-five postoperative patients (12 cranial, 13 spinal) were identified to be at high risk of operative debridement. All 25 patients were prescribed a topical application of ALH, which was easily adopted without patient-related adverse events. Seven (four cranial, three spinal) patients required operative debridement and treatment with long-term antibiotic therapy. CONCLUSIONS: In this small case series of neurosurgical patients who were at risk of poor wound healing, the application of medical-grade ALH was well tolerated without patient-reported adverse events. The ALH may have prevented the need for operative debridement in the majority of patients. Further prospective studies are necessary to establish its efficacy in wound healing in the neurosurgical population.

A system divided: the state of neurosurgical training in modern-day Vietnam.

The current report is the first of its kind in describing the neurosurgical training in modern-day Vietnam. Starting with in-depth face-to-face interviews, followed by electronically distributed questionnaires, a detailed picture of the training systems emerged.Neurosurgical training in Vietnam is multifaceted and dichotomous. The country of nearly 100 million people currently has only one neurosurgery-specific residency program, at the University of Medicine and Pharmacy at Ho Chi Minh City (UMPHCMC). This program lasts for 3 years, and Westerners might recognize many similarities to programs native to their countries. A similar training program exists in the north, at the Hanoi Medical University, but at this institution, trainees focus on neurosurgery only in the final year of their 3-year training. Neurosurgical training that resembles the program in Hanoi permeates the rest of the country, and the goal for all of the programs is to rapidly produce surgeons who can be dispersed throughout the country to treat patients requiring urgent neurosurgical procedures who are medically unsuitable for transfer to large urban centers and multispecialty hospitals. For the privilege of practicing elective neurosurgery, trainees around the country are required to acquire further training in Ho Chi Minh City or Hanoi or during fellowships abroad.A clear description of the neurosurgical training systems in Vietnam is hard to achieve, as there exist many diverse pathways and no standard definition of the endpoint for training. Unification and a clearer certification standard will likely help to elevate the standards of training and the state of neurosurgical practice in Vietnam.

A systematic review of endovascular stent-electrode arrays, a minimally invasive approach to brain-machine interfaces.

OBJECTIVE: The goal of this study was to systematically review the feasibility and safety of minimally invasive neurovascular approaches to brain-machine interfaces (BMIs). METHODS: A systematic literature review was performed using the PubMed database for studies published between 1986 and 2019. All studies assessing endovascular neural interfaces were included. Additional studies were selected based on review of references of selected articles and review articles. RESULTS: Of the 53 total articles identified in the original literature search, 12 studies were ultimately selected. An additional 10 articles were included from other sources, resulting in a total of 22 studies included in this systematic review. This includes primarily preclinical studies comparing endovascular electrode recordings with subdural and epidural electrodes, as well as studies evaluating stent-electrode gauge and material type. In addition, several clinical studies are also included. CONCLUSIONS: Endovascular stent-electrode arrays provide a minimally invasive approach to BMIs. Stent-electrode placement has been shown to be both efficacious and safe, although further data are necessary to draw comparisons between subdural and epidural electrode measurements given the heterogeneity of the studies included. Greater access to deep-seated brain regions is now more feasible with stent-electrode arrays; however, further validation is needed in large clinical trials to optimize this neural interface. This includes the determination of ideal electrode material type, venous versus arterial approaches, the feasibility of deep brain stimulation, and more streamlined computational decoding techniques.

How I do it: superficial temporal artery to middle cerebral artery bypass for treatment of giant middle cerebral artery aneurysm.

BACKGROUND: Giant middle cerebral artery aneurysms are frequently anatomically complicated. Trapping may yield poor outcome, and bypass revascularization is often necessary as an adjunctive treatment to preserve flow. METHOD: The technical nuances of superficial temporal artery to middle cerebral artery bypass are described in the setting of clip reconstruction of giant middle cerebral artery (MCA) aneurysm. In addition to an operative video, the anatomy and surgical technique are demonstrated in virtual reality to enhance the didactic clarity. CONCLUSION: Meticulous technique is paramount for successful superficial temporal artery MCA bypass. Along with clip reconstruction, it is a critical part of the treatment of complex, giant MCA aneurysms.

The impact of COVID-19 on neurosurgeons and the strategy for triaging non-emergent operations: a global neurosurgery study.

OBJECT: The COVID-19 pandemic has disrupted all aspects of society globally. As healthcare resources had to be preserved for infected patients, and the risk of in-hospital procedures escalated for uninfected patients and staff, neurosurgeons around the world have had to postpone non-emergent procedures. Under these unprecedented conditions, the decision to defer cases became increasingly difficult as COVID-19 cases skyrocketed. METHODS: Data was collected by self-reporting surveys during two discrete periods: the principal survey accrued responses during 2 weeks at the peak of the global pandemic, and the supplemental survey accrued responses after that to detect changes in opinions and circumstances. Nine hypothetical surgical scenarios were used to query neurosurgeons' opinion on the risk of postponement and the urgency to re-schedule the procedures. An acuity index was generated for each scenario, and this was used to rank the nine cases. RESULTS: There were 494 respondents to the principal survey from 60 countries. 258 (52.5%) reported that all elective cases and clinics have been shut down by their main hospital. A total of 226 respondents (46.1%) reported that their operative volume had dropped more than 50%. For the countries most affected by COVID-19, this proportion was 54.7%. There was a high degree of agreement among our respondents that fast-evolving neuro-oncological cases are non-emergent cases that nonetheless have the highest risk in postponement, and selected vascular cases may have high acuity as well. CONCLUSION: We report on the impact of COVID-19 on neurosurgeons around the world. From their ranking of the nine case scenarios, we deduced a strategic scheme that can serve as a guideline to triage non-emergent neurosurgical procedures during the pandemic. With it, hopefully, neurosurgeons can continue to serve their patients without endangering them either neurologically or risking their exposure to the deadly virus.

An anatomical study of the foramen of Monro: implications in management of pineal tumors presenting with hydrocephalus.

BACKGROUND: For pineal tumors presenting with hydrocephalus, simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is commonly used as the initial step in management. To analyze the restriction which the foramen of Monro poses to this procedure, one must start with a detailed description of the microsurgical anatomy of the foramen in living subjects. However, the orientation and shape of the foramen of Monro make this description difficult with conventional imaging techniques. METHOD: Virtual reality technology was applied on MRIs on living subject without hydrocephalus, as well as patients with hydrocephalus, to generate precise anatomical models with sub-millimeter accuracy. The morphometry of the foramen of Monro was studied in each group. In addition, displacement of the margins of the foramen was studied in detail for simultaneous ETV and pineal tumor biopsy through a single burr hole. RESULTS: In 30 normal subjects, the foramen of Monro had oval-shaped openings averaging 5.23 mm2. The foramen was larger in people above age 55 (p = 0.007) and on the left side compared to the right (p = 0.002). For patients with clinical presentation of hydrocephalus, the average opening was 32.6 mm2. Simulated single burr hole simultaneous ETV and pineal tumor biopsy was performed in 10 specimens. Average displacement of the posterior and anterior margins of the foramen was 5.71 mm and 5.76 mm, respectively. However, maximum displacement reached 9.3 mm posteriorly and 10 mm anteriorly. CONCLUSIONS: The foramen of Monro is an oval-shaped cylinder that changes in size and orientation in the hydrocephalic patient. If universally applied to all patients regardless of foramen and tumor size, ETV/biopsy can displace structures around the Foramen of Monro up to 1 cm, which can potentially lead to neurological damage. Careful pre-operative assessment is critical to determine if a single burr hole approach is safe.

S2-AI screw placement with the aide of electronic conductivity device monitoring: a retrospective analysis.

STUDY DESIGN: A retrospective analysis of two consecutive patients who underwent a novel surgical technique. OBJECTIVE: A report of a novel surgical technique utilizing an electronic conductivity device guidance to aide placement of S2-Alar-Iliac (S2-AI) instrumentation. Electronic conductivity guidance for instrumentation of the thoracolumbar spine is an accepted means of improving intraoperative accuracy. Although commercially available for percutaneous techniques, there is a paucity of literature regarding its use. Percutaneous implantation of S2-AI screws has been previously described as another technique surgeons can avail, primarily employing fluoroscopy as a means of intraoperative feedback. We describe a novel technique that utilizes electronic conductivity as an added feedback measure to increase accuracy of percutaneous S2-AI fixation. METHODS: Two patients were treated by the senior author (FAS) who underwent surgery employing S2-AI fixation utilizing an electronic conductivity device (Pediguard cannulated probe, Spineguard, Paris, France). The surgical technique, case illustrations, and radiographic outcomes are discussed. RESULTS: Stable and accurate fixation was attained in both patients. There were no peri-operative complications related to hardware placement. CONCLUSION: To the authors' knowledge, this is the first reported literature combining S2-AI screws with electronic conductivity for immediate intraoperative feedback. This technique has the opportunity to provide surgeons with increased accuracy for placement of S2-AI screws while improving overall radiation safety. This feedback can be particularly helpful when surgeons are learning new techniques such as placement of S2AI screws.

The Inaugural "Century" of Mixed Reality in Cranial Surgery: Virtual Reality Rehearsal/Augmented Reality Guidance and Its Learning Curve in the First 100-Case, Single-Surgeon Series.

BACKGROUND AND OBJECTIVE: Virtual reality (VR) refers to a computer-generated three-dimensional space in which a surgeon can interact with patient-specific anatomic models for surgical planning. Augmented reality (AR) is the technology that places computer-generated objects, including those made in VR, into the surgeon's visual space. Together, VR and AR are called mixed reality (MxR), and it is gaining importance in neurosurgery. MxR is helpful for selecting and creating templates for an optimal surgical approach and identifying key anatomic landmarks intraoperatively. By reporting our experience with the first 100 consecutive cases planned with VR and executed with AR, our objective is to detail the learning curve and encountered obstacles while adopting the new technology. METHODS: This series includes the first 100 consecutive complex cranial cases of a single surgeon for which MxR was intended for use. Effectiveness of the VR rehearsal and AR guidance was analyzed for four specific contributions: (1) opening size, (2) precise craniotomy placement, (3) guidance toward anatomic landmarks or target, and (4) antitarget avoidance. Seventeen cases in the study cohort were matched with historical non-MxR cases for comparison of outcome parameters. The cases in which MxR failed were plotted over time to determine the nature of the "learning curve." RESULTS: AR guidance was abandoned in eight operations because of technical problems, but problem-free application of MxR increased between the 44th and 63rd cases. This provides some evidence of proficiency acquisition in between. Comparing the 17 pairs of matched MxR and non-MxR cases, no statistically significant differences exist in the groups regarding blood loss, length of stay nor duration of surgery. Cases where MxR had above-expectation performances are highlighted. CONCLUSION: MxR is a powerful tool that can help tailor operations to patient-specific anatomy and provide efficient intraoperative guidance without additional time for surgery or hospitalization.

Considerations for delayed-onset spinal arachnoid web after intracranial subarachnoid hemorrhage.

Spinal arachnoid web (AW) is a rare condition causing spinal cord-related issues. Its cause is often idiopathic but can be linked to past trauma or spine surgery. We describe two cases of AWs that developed after subarachnoid hemorrhage (SAH). Case #1 is a 71-year-old male with nonaneurysmal SAH who developed myelopathy 1 year later. Magnetic resonance imaging revealed upper thoracic cord edema and an AW. Case #2 is a 57-year-old female who underwent coiling of a ruptured basilar artery aneurysm and ventriculoperitoneal shunting for hydrocephalus. Twenty months later, she developed mid-thoracic AW requiring surgical resection. Both patients showed symptom improvement postresection avoiding further reoperation. History of SAH is emerging as a risk factor for AW development, emphasizing the importance of monitoring delayed-onset myelopathy and back pain in recent SAH patients.

Transorbital Surgical Corridor: An Anatomic Analysis of Ocular Globe Retraction and the Associated Exposure for the Transpalpebral Orbital Rim Preserving Endoscopic Orbitotomy (TORPEDO) Approach.

BACKGROUND AND OBJECTIVES: The transorbital approach varies by the extent of bony removal and the target. Orbital rim-sparing transorbital approach with removal of only the orbit's posterior wall provides optimal cosmetic results, without the need for reconstruction. The size of this corridor, limited by the medial globe retraction, has not yet been defined and is difficult to determine in cadavers because of postmortem tissue desiccation. By using patient-specific models in virtual reality, precise areas and degrees of surgical freedom (AOF and DOF, respectively) provided by globe retraction were calculated. These measurements define a potential maximum safe AOF and DOF, as well as the globe retraction, needed to achieve a sufficient surgical corridor. METHODS: Using a virtual reality system, transorbital rim-preserving craniectomies were performed. The axial and sagittal DOF as well as AOF were calculated lateral to the globe, limited by the orbital rim and globe, with an anterior clinoid target. The DOFs and AOFs were calculated for each degree of medial globe retraction and analyzed using paired t tests. RESULTS: With only 5 mm of retraction, the AOF was 886 mm 2 , while at 10 mm, the AOF was 1546 mm 2 . This increase between 5 and 10 mm allowed for the largest increase in surgical working corridor ( P = .02). At 15 mm of retraction (previously studied point at which intraocular pressure raises), the AOF averaged 2189 mm 2 and axial DOF averaged 23.1°. Eighteen DOF (a previously studied point needed to achieve sufficient working space for 2 instruments) was achieved at 11 mm on average, generating 1675 mm 2 AOF. CONCLUSION: Globe retraction of 11 mm is needed to achieve sufficient DOF for 2 surgical instruments, and 15 mm of retraction is a conservative limit that provides comparable AOFs with similar cranial approaches.

Time Thresholds for Using Pressure Reactivity Index in Neuroprognostication for Patients With Severe Traumatic Brain Injury.

BACKGROUND AND OBJECTIVES: Severe traumatic brain injury (sTBI) represents a diffuse, heterogeneous disease where therapeutic targets for optimizing clinical outcome remain unclear. Mean pressure reactivity index (PRx) values have demonstrated associations with clinical outcome in sTBI. However, the retrospective derivation of a mean value diminishes its bedside significance. We evaluated PRx temporal profiles for patients with sTBI and identified time thresholds suggesting optimal neuroprognostication. METHODS: Patients with sTBI and continuous bolt intracranial pressure monitoring were identified. Outcomes were dichotomized by disposition status ("good outcome" was denoted by home and acute rehabilitation). PRx values were obtained every minute by taking moving correlation coefficients of intracranial pressures and mean arterial pressures. Average PRx trajectories for good and poor outcome groups were calculated by extending the last daily averaged PRx value to day 18. Each patient also had smoothed PRx trajectories that were used to generate "candidate features." These "candidate features" included daily average PRx's, cumulative first-order changes in PRx and cumulative second-order changes in PRx. Changes in sensitivity over time for predicting poor outcome was then evaluated by generating penalized logistic regression models that were derived from the "candidate features" and maximized specificity. RESULTS: Among 33 patients with sTBI, 18 patients achieved good outcome and 15 patients had poor outcome. Average PRx trajectories for the good and poor outcome groups started on day 6 and consistently diverged at day 9. When targeting a specificity >83.3%, an 85% maximum sensitivity for determining poor outcome was achieved at hospital day 6. Subsequent days of PRx monitoring showed diminishing sensitivities. CONCLUSION: Our findings suggest that in a population of sTBI, PRx sensitivities for predicting poor outcome was maximized at hospital day 6. Additional study is warranted to validate this model in larger populations.

Neurosurgical management of patients with Ehlers-Danlos syndrome: A descriptive case series.

Introduction: Ehlers-Danlos syndrome (EDS) is a connective tissue disorder that has been linked to several neurological problems including Chiari malformations, atlantoaxial instability (AAI), craniocervical instability (CCI), and tethered cord syndrome. However, neurosurgical management strategies for this unique population have not been well-explored to date. The purpose of this study is to explore cases of EDS patients who required neurosurgical intervention to better characterize the neurological conditions they face and to better understand how neurosurgeons should approach the management of these patients. Methods: A retrospective review was done on all patients with a diagnosis of EDS who underwent a neurosurgical operation with the senior author (FAS) between January 2014 and December 2020. Demographic, clinical, operative, and outcome data were collected, with additional radiographic data collected on patients chosen as case illustrations. Results: Sixty-seven patients were identified who met the criteria for this study. The patients experienced a wide array of preoperative diagnoses, with Chiari malformation, AAI, CCI, and tethered cord syndrome representing the majority. The patients underwent a heterogeneous group of operations with the majority including a combination of the following procedures- suboccipital craniectomy, occipitocervical fusion, cervical fusion, odontoidectomy, and tethered cord release. The vast majority of patients experienced subjective symptomatic relief from their series of procedures. Conclusions: EDS patients are prone to instability, especially in the occipital-cervical region, which may predispose these patients to require a higher rate of revision procedures and may require modifications in neurosurgical management that should be further explored.

Awake transradial middle meningeal artery embolization and twist drill craniostomy for chronic subdural hematomas in the elderly: case series and technical note.

BACKGROUND: Due to prohibitive perioperative risk factors, optimal treatment for chronic subdural hematomas (cSDH) in the elderly remains unclear. Minimally invasive techniques are a viable option and include bedside subdural evacuation port system (SEPS), as well as prevention of recurrence with middle meningeal artery (MMA) embolization. We present a case series of elderly patients undergoing combined transradial MMA embolization and bed-side craniostomy as primary treatment for cSDH. METHODS: Patients 70 years and older from 2019 to 2020 that underwent single setting, awake transradial MMA embolization with concurrent SEPS placement under local anesthesia were included. Those with prior treatments, interventions performed under general anesthesia, or with less than 60-day follow-up were excluded. Descriptive analyses of baseline characteristics, radiologic parameters, comorbidities, and outcome measures were completed. RESULTS: Twenty elderly patients (mean age of 81.0 years) with multiple comorbidities underwent 28 MMA embolization+SEPS procedures as primary treatment for cSDH. Mean cSDH thickness was 1.8cm±0.6 cm with 7.3±3.9 mm midline shift. All patients tolerated the procedure well. 1/20 (5.0%) patients died within 30 days of the procedure. A majority of patients were discharged to home (12/20; 60.0%). There was an average of 3.6-month follow-up and one patient (5.0%) developed recurrence in the follow-up period requiring further intervention. CONCLUSIONS: In select elderly patients with high perioperative risk factors, primary treatment of cSDH using awake transradial MMA embolization+SEPS placement is a minimally invasive, feasible, and safe option. Further comparative studies are warranted to evaluate efficacy of the treatment.