Role of Inflammatory Processes in Hemorrhagic Stroke.

Hemorrhagic stroke is the deadliest form of stroke and includes the subtypes of intracerebral hemorrhage and subarachnoid hemorrhage. A common cause of hemorrhagic stroke in older individuals is cerebral amyloid angiopathy. Intracerebral hemorrhage and subarachnoid hemorrhage both lead to the rapid collection of blood in the central nervous system and generate inflammatory immune responses that involve both brain resident and infiltrating immune cells. These responses are complex and can contribute to both tissue recovery and tissue injury. Despite the interconnectedness of these major subtypes of hemorrhagic stroke, few reviews have discussed them collectively. The present review provides an update on inflammatory processes that occur in response to intracerebral hemorrhage and subarachnoid hemorrhage, and the role of inflammation in the pathophysiology of cerebral amyloid angiopathy-related hemorrhage. The goal is to highlight inflammatory processes that underlie disease pathology and recovery. We aim to discuss recent advances in our understanding of these conditions and identify gaps in knowledge with the potential to develop effective therapeutic strategies.

Stereotactic electroencephalography in epilepsy patients for mapping of neural circuits related to emotional and psychiatric behaviors: a systematic review.

OBJECTIVE: Stereotactic electroencephalography (sEEG) is an increasingly utilized method for identifying electrophysiological processes underlying sensorimotor, cognitive, and emotional behaviors. In this review, the authors outline current research using sEEG to investigate the neural activity underlying emotional and psychiatric behaviors. Understanding the current structure of intracranial research using sEEG will inform future studies of psychiatric disease and therapeutics for effective neuromodulation. METHODS: The authors conducted a comprehensive systematic review of studies according to PRISMA guidelines to investigate behaviors related to psychiatric conditions in patients with epilepsy undergoing monitoring with sEEG. Articles indexed on PubMed between 2010 and 2022 were included if they studied emotions or affective behaviors or met the National Institute of Mental Health Research Domain Criteria positive and negative valence domains. Data extracted from articles included study sample size, paradigms and behavioral tasks employed, cortical and subcortical targets, EEG analysis methods, and identified electrophysiological activity underlying the studied behavior. The Newcastle-Ottawa Scale was used to assess bias risk. RESULTS: Thirty-two primary articles met inclusion criteria. Study populations ranged from 3 to 39 patients. The most common structures investigated were the amygdala, insula, orbitofrontal cortex (OFC), hippocampus, and anterior cingulate cortex (ACC). Paradigms, stimuli, and behavioral tasks widely varied. Time-frequency analyses were the most common, followed by connectivity analyses. Multiple oscillations encoded a variety of behaviors related to emotional and psychiatric conditions. High gamma activity was observed in the amygdala and anterior insula in response to aversive audiovisual stimuli and in the OFC in response to reward processing. ACC beta band power increases and hippocampal-amygdala beta coherence variations were predictive of worsening mood states. Insular and amygdalar theta oscillations encoded social pain and fear learning, respectively. Most studies performed passing recordings, allowing for the decoding of affective states and depression symptoms, while other studies utilized direct stimulation, such as in the OFC to improve mood symptoms. CONCLUSIONS: Stereotactic EEG in epilepsy has identified multiple corticolimbic structures with specific oscillatory and synchronization activity underlying a diverse range of behaviors related to emotions and affective conditions. Given the heterogeneity of psychiatric conditions, sEEG provides an opportunity to study these neural correlates to develop personalized effective neuromodulatory treatments. Future studies should focus on optimizing paradigms and tasks to investigate a broad range of behavioral phenotypes that overlap across psychiatric conditions.

Effects of 24-hour versus night-float call schedules on the clinical and operative experiences of postgraduate year 2 and 3 neurosurgical residents.

OBJECTIVE: To comply with the removal of the 88-hour week exemption and to support additional operative experience during junior residency, Oregon Health & Science University (OHSU) switched from a night-float call schedule to a modified 24-hour call schedule on July 1, 2019. This study compared the volumes of clinical, procedural, and operative cases experienced by postgraduate year 2 (PGY-2) and PGY-3 residents under these systems. METHODS: The authors retrospectively studied billing and related clinical records, call schedules, and Accreditation Council for Graduate Medical Education case logs for PGY-2 and PGY-3 residents at OHSU, a tertiary academic health center, for the first 4 months of the academic years from 2017 to 2020. The authors analyzed the volumes of new patient consultations, bedside procedures, and operative procedures performed by each PGY-2 and PGY-3 resident during these years, comparing the volumes experienced under each call system. RESULTS: Changing from a PGY-2 resident-focused night-float call system to a 24-hour call system that was more evenly distributed between PGY-2 and PGY-3 residents resulted in decreased volume of new patient consultations, increased volume of operative procedures, and no change in volume of bedside procedures for PGY-2 residents. PGY-3 residents experienced a decrease in operative procedure volume under the 24-hour call system. CONCLUSIONS: Transition from a night-float system to a 24-hour call system altered the distribution of clinical and procedural experiences between PGY-2 and PGY-3 residents. Further research is necessary to understand the impact of these changes on educational outcomes, quality and safety of patient care, and resident satisfaction.

Rare Case of Pediatric Disseminated Choroid Plexus Papilloma: Literature Review and Call for Reclassification.

INTRODUCTION: Choroid plexus tumors are rare neuroectodermal tumors that arise from the choroid plexus. Choroid plexus papillomas (CPPs) represent the lowest grade of these types of tumors and have a WHO grade I designation. Despite their typical low grade, some CPPs can exhibit aggressive behaviors including parenchymal invasion and dissemination throughout the neuro-axis. Due to their association with the choroid plexus, patients with CPP commonly present with signs and symptoms of hydrocephalus and increased intracranial pressure. CASE PRESENTATION: A 2-year-old male presented in extremis with acute hydrocephalus and seizure. He was found to have a large left intraventricular mass with innumerable intraparenchymal and extra-axial cysts throughout his neuro-axis. A literature review revealed five similar disseminated CPP cases with innumerable lesions. This is the youngest reported patient with disseminated CPP and the first with multiple compressive lesions. Following cranial resection and thoracic decompression, the patient's lesions have remained stable (2 years of follow-up). A literature search of the PubMed/Medline databases was performed using the search terms ["disseminated choroid plexus papilloma" OR "choroid plexus papilloma" OR "metastatic choroid plexus papilloma"] up to March 2021. Articles were then screened for similar patient radiographic presentation and histological diagnosis. To mitigate publication bias, referenced articles were utilized to identify other case reports and case series. DISCUSSION/CONCLUSION: We describe a rare case of a lateral ventricle CPP with widespread leptomeningeal dissemination causing acute obstructive hydrocephalus and compressive myelopathy requiring cerebrospinal fluid diversion and intracranial resection followed by thoracic spine decompression. This case report serves to broaden knowledge of disseminated CPP and to encourage complete neuro-axis imaging for choroid plexus tumors. Additionally, we propose a naming paradigm refinement that includes radiographic characteristics.

A retrospective analysis of 513 patients undergoing pedicle subtraction osteotomy for adult spinal deformity by a single surgical team: are elderly patients at an elevated risk for complications?

OBJECTIVE: This study aimed to assess whether elderly patients (aged ≥ 70 years) face an elevated risk of complications following pedicle subtraction osteotomy (PSO) for adult spinal deformity (ASD) compared with younger patients (< 70 years) and to evaluate if clinical and radiological outcomes differ between these age groups. METHODS: A retrospective analysis of 513 patients undergoing PSO for ASD by a single surgical team between January 2006 and January 2023 was conducted. Patients were categorized by age (≥ 70 years and < 70 years). Data on clinical, demographic, comorbidity, and radiographic details were collected and compared between the groups. For health-related quality of life assessment, the authors recorded the Oswestry Disability Index (ODI), numeric rating scale (NRS), and Scoliosis Research Society-22 revised (SRS-22r) scores preoperatively and at 6 weeks and 1 year postoperatively. Perioperative complications included major (neurological deficit, death, acute myocardial infarction, stroke), minor (ileus, arrhythmia, delirium), and intraoperative (durotomy, vascular injury). RESULTS: Of 513 patients, 412 were included in the study. Clinical outcomes, as measured by NRS, ODI, and SRS-22r scores, were comparable between groups, with both groups showing significant improvements postoperatively. Radiographic outcomes also showed significant and comparable improvements in sagittal balance and spinopelvic harmony in both groups. Deformity corrections were also well maintained at 1 year postoperatively. The elderly group (mean age 75.48 years) had a higher rate of perioperative complications (44.64%) than the younger group (mean age 59.60 years; 30.33%) (p = 0.0030), primarily minor complications such as delirium and arrhythmia (16.07% vs 8.61%, p = 0.0279). There was no significant difference between groups regarding the major complication rate (elderly group: 20.83% vs younger group: 14.34%, p = 0.1087), intraoperative complication rate (2.98% vs 3.69%, p = 0.6949), short-term complication rate (10.12% vs 8.20%, p = 0.5024), mechanical complication rate (30.95% vs 32.79%, p = 0.6949), and reoperation rate due to mechanical complications (38.46% vs 43.75% p = 0.5470). CONCLUSIONS: Elderly patients undergoing PSO for ASD experience a higher rate of minor complications but can achieve clinical and radiological outcomes that are comparable to those of younger patients. The authors found no significant increase in major, intraoperative, short-term, or mechanical complication rates and their subsequent reoperation rates among the elderly. These findings underscore the effectiveness of PSO in improving the quality of life for patients with ASD across age groups, emphasizing the critical role of personalized perioperative management in enhancing outcomes and minimizing risks for all patients.

Photoreversible micellar solution as a smart drag-reducing fluid for use in district heating/cooling systems.

A photoresponsive micellar solution is developed as a promising working fluid for district heating/cooling systems (DHCs). It can be reversibly switched between a drag reduction (DR) mode and an efficient heat transfer (EHT) mode by light irradiation. The DR mode is advantageous during fluid transport, and the EHT mode is favored when the fluid passes through heat exchangers. This smart fluid is an aqueous solution of cationic surfactant oleyl bis(2-hydroxyethyl)methyl ammonium chloride (OHAC, 3.4 mM) and the sodium salt of 4-phenylazo benzoic acid (ACA, 2 mM). Initially, ACA is in a trans configuration and the OHAC/ACA solution is viscoelastic and exhibits DR (of up to 80% relative to pure water). At the same time, this solution is not effective for heat transfer. Upon UV irradiation, trans-ACA is converted to cis-ACA, and in turn, the solution is converted to its EHT mode (i.e., it loses its viscoelasticity and DR) but it now has a heat-transfer capability comparable to that of water. Subsequent irradiation with visible light reverts the fluid to its viscoelastic DR mode. The above property changes are connected to photoinduced changes in the nanostructure of the fluid. In the DR mode, the OHAC/trans-ACA molecules assemble into long threadlike micelles that impart viscoelasticity and DR capability to the fluid. Conversely, in the EHT mode the mixture of OHAC and cis-ACA forms much shorter cylindrical micelles that contribute to negligible viscoelasticity and effective heat transfer. These nanostructural changes are confirmed by cryo-transmission electron microscopy (cryo-TEM), and the photoisomerization of trans-ACA and cis-ACA is verified by (1)H NMR.

Birch reductive alkylation of methyl m-(hydroxymethyl)benzoate derivatives and the behavior of o- and p-(hydroxymethyl)benzoates under reductive alkylation conditions.

Birch reductive alkylation of methyl m-(hydroxymethyl)benzoate derivatives, using lithium in ammonia-tetrahydrofuran in the presence of tert-butyl alcohol, can be achieved without significant loss of benzylic oxygen substituents. Similar treatment of o- and p-(hydroxymethyl)benzoate derivatives results largely in loss of benzylic oxygen substituents. The results are rationalized by computations describing electron density patterns in the putative radical anion intermediate involved in these reactions.

Evaluation of Models for Estimating Hydraulic Conductivity in Glacial Aquifers with NMR Logging.

Nuclear magnetic resonance (NMR) logging is a promising method for estimating hydraulic conductivity (K). During the past ∼60 years, NMR logging has been used for petroleum applications, and different models have been developed for deriving estimates of permeability. These models involve calibration parameters whose values were determined through decades of research on sandstones and carbonates. We assessed the use of five models to derive estimates of K in glacial aquifers from NMR logging data acquired in two wells at each of two field sites in central Wisconsin, USA. Measurements of K, obtained with a direct push permeameter (DPP), KDPP , were used to obtain the calibration parameters in the Schlumberger-Doll Research, Seevers, Timur-Coates, Kozeny-Godefroy, and sum-of-echoes (SOE) models so as to predict K from the NMR data; and were also used to assess the ability of the models to predict KDPP . We obtained four well-scale calibration parameter values for each model using the NMR and DPP measurements in each well; and one study-scale parameter value for each model by using all data. The SOE model achieved an agreement with KDPP that matched or exceeded that of the other models. The Timur-Coates estimates of K were found to be substantially different from KDPP . Although the well-scale parameter values for the Schlumberger-Doll, Seevers, and SOE models were found to vary by less than a factor of 2, more research is needed to confirm their general applicability so that site-specific calibration is not required to obtain accurate estimates of K from NMR logging data.

Bone morphogenetic protein and cancer in spinal fusion: a propensity score-matched analysis.

OBJECTIVE: Bone morphogenetic protein (BMP) has been increasingly used in spinal surgery to promote arthrodesis. Because BMP stimulates cellular proliferation, its association with tumorigenesis is a concern. Previous research has generated conflicting conclusions on the risk of cancer in patients receiving BMP. The authors aimed to compare the incidence of solid organ and hematopoietic malignancies in patients undergoing spinal arthrodesis with or without BMP. METHODS: The PearlDiver Mariner Patient Claims Database was queried for patients undergoing thoracolumbar fusion between 2015 and 2021. Patients with preexisting malignancy were excluded. Data were analyzed for incidence of solid organ malignancy and hematopoietic malignancy diagnosed after spinal surgery. Propensity score matching using age, sex, tobacco usage, and year of surgery was performed between patients who did and those who did not receive BMP. RESULTS: Among patients without prior solid organ malignancy, BMP was used in 22,139 patients and not used in 306,249. In the propensity score-matched group, 3.1% of the BMP group developed solid organ malignancy following surgery compared with 3.5% in the non-BMP group. The relative risk (RR) of developing solid organ malignancy after BMP exposure was 0.89 (95% CI 0.81-0.98, p = 0.02). Among patients without prior hematopoietic malignancy, BMP was used in 23,505 patients and not used in 328,796 patients. In the propensity score-matched group, 0.4% of the BMP group developed hematopoietic malignancy compared with 0.6% of the non-BMP group. The RR of developing hematopoietic malignancy after BMP exposure was 0.71 (95% CI 0.55-0.93, p = 0.015). CONCLUSIONS: BMP use in thoracolumbar fusion was not associated with an increased risk of new malignancy, which further supports emerging data on the lack of an association between BMP use and increased malignancy.

Surgical site infection in thoracic and lumbar fractures: incidence and risk factors in 11,401 patients from a nationwide administrative database.

BACKGROUND CONTEXT: The rate of surgical site infection (SSI) following elective spine surgery ranges from 0.5%‒10%. Published reports suggest a higher SSI rate in non-elective spine surgery such as spine trauma; however, there is a paucity of large database studies examining this issue. PURPOSE: The objective of this study was to investigate the incidence and risk factors of SSI in patients undergoing spine surgery for thoracic and lumbar fractures in a large population database. STUDY DESIGN/SETTING: This is a retrospective study utilizing the PearlDiver Patient Claims Database. PATIENT SAMPLE: Patients undergoing spine surgery for thoracic and lumbar fractures between 2015-2020 were identified in the PearlDiver Patient Claims Database using ICD-10 codes. Patients were excluded who had another surgery either 14 days before or 21 days after the index spine surgery, or pathologic fracture. OUTCOME MEASURES: Rate of surgical site infection. METHODS: Clinical data collected from the PearlDiver database based on ICD-10 codes included gender, age, diabetes, smoking status, obesity, Elixhauser Comorbidity Index (ECI), Charlson Comorbidity Index (CCI), and SSI. Univariate analysis was used to assess the association of potential risk factors and SSI. Multivariable analysis was used to identify independent risk factors of SSI. The authors have no conflicts of interest or funding sources to declare. RESULTS: A total of 11,401 patients undergoing spine surgery for thoracic and lumbar fractures met inclusion criteria, and 1,065 patients were excluded. 860 patients developed SSI (7.5%). Risk factors significantly associated with SSI in univariate analysis included diabetes (OR 1.50; 95% CI, 1.30‒1.73; p<.001), obesity (OR 1.66; 95% CI, 1.44‒1.92; p<.001), increased age (p<.001), ECI (p<.001), and CCI (p<.001). On multivariable analysis, obesity and ECI were independently associated with SSI (p<.001 and p<.001, respectively). CONCLUSIONS: Non-elective surgery for thoracic and lumbar fractures is associated with a 7.5% risk of SSI. Obesity and ECI are independent predictors of SSI in this population. Limitations include the reliance on accurate insurance coding which may not fully capture all SSI, and in particular superficial SSI. These findings provide a broad overview of the risk of SSI in this population at a national level and may also help counsel patients regarding risk.

Early postoperative MRI findings following anterior cervical discectomy and fusion: What to expect when the unexpected happens.

Background: Magnetic resonance imaging (MRI) is not routinely ordered following spinal fusion. Some literature suggests MRIs are unhelpful due to postoperative changes that obscure interpretation. We aim to describe findings of acute postoperative MRI following anterior cervical discectomy and fusion (ACDF). Methods: The authors retrospectively analyzed adult MRIs completed within 30 days of ACDF (from 2005-2022). T1 and T2 signal intensity in the interbody space dorsal to the graft, mass effect on the dura/spinal cord, intrinsic spinal cord T2 signal, and interpretability were reviewed. Results: In 38 patients there were 58 ACDF levels (1, 2, and 3 levels; 23, 10, and 5, respectively). MRIs were completed on mean postoperative day 8.37 (range; 0-30 days). T1-weighted imaging was described as isointense, hyperintense, heterogenous, and hypointense in 48 (82.8%), 5 (8.6%), 3 (5.2%), and 2 levels (3.4%), respectively. T2-weighted imaging was described as hyperintense, heterogenous, isointense, and hypointense in 41 (70.7%), 12 (20.7%), 3 (5.2%), and 2 levels (3.4%), respectively. There was no mass effect in 27 levels (46.6%), 14 (24.1%) had thecal sac compression, and 17 (29.3%) had cord compression. Conclusions: The majority of MRIs exhibited readily compression and intrinsic spinal cord signal even with various types of fusion constructs. Early MRI after lumbar surgery can be difficult to interpret. However, our results support the use of early MRI to investigate neurological complaints following ACDF. Our findings do not support the idea that epidural blood products and mass effect on the cord are seen in most postoperative MRIs after ACDF.

Evaluating Surgical Cervical Arthrodesis With a Novel MRI Grading Score.

STUDY DESIGN: This was a single-institution retrospective study. OBJECTIVE: Evaluate a magnetic resonance imaging (MRI)-scoring system to differentiate arthrodesis from pseudoarthrosis following anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: Diagnostic workup following fusion surgery often includes MRI to evaluate neural structures and computed tomography (CT) and/or dynamic x-rays to evaluate instrumentation and arthrodesis. The use of MRI alone for these evaluations would protect patients from harmful CT and x-ray ionizing radiation. METHODS: Neurosurgical attending evaluated CTs for arthrodesis or pseudoarthrosis. Blinded neuroradiology attending and neurosurgery senior resident evaluated independent T1 and T2 region of interest (ROI) signal intensity over instrumented disk space. Cerebral spinal fluid (CSF) at the cisterna magnum and distal adjacent uninstrumented vertebral body (VB) were also calculated. ROI interspace /ROI CSF and ROI interspace /ROI VB quotients were used to create T1- and T2-interspace interbody scores (IIS). RESULTS: Study population (n=64 patients, 50% female) with a mean age of 51.72 years and 109 instrumented levels with 45 fused levels (41.3%) were included. T1-weighted MRI, median T1-IIS CSF for arthrodesis was 176.20 versus 130.92 for pseudoarthrosis ( P <0.0001), T1-IIS VB for arthrodesis was 68.52 and pseudoarthrosis was 52.71 ( P <0.0001). T2-weighted MRI, median T2-IIS CSF for arthrodesis was 27.72 and 14.21 for pseudoarthrosis ( P <0.0001), while T2-IIS VB for arthrodesis was 67.90 and 41.02 for pseudoarthrosis ( P <0.0001). The greatest univariable discriminative capability for arthrodesis via AUROC was T1-IIS VB (0.7743). CONCLUSION: We describe a novel MRI scoring system that may help determine arthrodesis versus pseudoarthrosis following anterior cervical discectomy and fusion. Postoperative symptomatic patients may only require MRI, which would protect patients from ionizing radiation. LEVEL OF EVIDENCE: Level IV.

Venous Sinus Stenting: Safety and Health Care Resource Evaluation for Optimal Recovery in an Evolving Health Care Environment.

BACKGROUND: Increasing evidence supports the effectiveness of venous sinus stenting (VSS) with favorable outcomes, safety, and expenses compared with shunting for idiopathic intracranial hypertension. Yet, no evidence is available regarding optimal postoperative recovery, which has increasing importance with the burdens on health care imposed by the coronavirus disease 2019 pandemic. We examined adverse events and costs after VSS and propose an optimal recovery pathway to maximize patient safety and reduce stress on health care resources. METHODS: A retrospective review was undertaken of elective VSS operations performed from May 2008 to August 2021 at a single institution. Primary data included hospital length of stay, intensive care unit (ICU) length of stay, adverse events, need for ICU interventions, and hospital costs. RESULTS: Fifty-three patients (98.1% female) met the inclusion criteria. Of these patients, 51 (96.2%) were discharged on postoperative day (POD) 1 and 2 patients were discharged on POD 2. Both patients discharged on POD 2 remained because of groin hematomas from femoral artery access. There were no major complications or care that required an ICU. Eight patients (15.1%) were lateralized to other ICUs or remained in a postanesthesia care unit because the neurosciences ICU was above capacity. Total estimated cost for initial recovery day in a neurosciences ICU room was $2361 versus $882 for a neurosurgery/neurology ward room. In our cohort, ward convalescence would save an estimated $79,866 for bed placement alone and increase ICU bed availability. CONCLUSIONS: Our findings reaffirm the safety of VSS. These patients should recover on a neurosurgery/neurology ward, which would save health care costs and increase ICU bed availability.

Response to Preoperative Dexamethasone Predicts Postoperative Neurological Improvement of Focal Neurological Deficits in Patients With Brain Metastases.

BACKGROUND: Steroids are used ubiquitously in the preoperative management of patients with brain tumor. The rate of improvement in focal deficits with steroids and the prognostic value of such a response are not known. OBJECTIVE: To determine the rate at which focal neurological deficits respond to preoperative corticosteroids in patients with brain metastases and whether such an improvement could predict long-term recovery of neurological function after surgery. METHODS: Patients with brain metastases and related deficits in language, visual field, or motor domains who received corticosteroids before surgery were identified. Characteristics between steroid responders and nonresponders were compared. RESULTS: Ninety six patients demonstrated a visual field (13 patients), language (19), or motor (64) deficit and received dexamethasone in the week before surgery (average cumulative dose 43 mg; average duration 2.7 days). 38.5% of patients' deficits improved with steroids before surgery, while 82.3% of patients improved by follow-up. Motor deficits were more likely to improve both preoperatively ( P = .014) and postoperatively ( P = .010). All 37 responders remained improved at follow-up whereas 42 of 59 (71%) of nonresponders ultimately improved ( P < .001). All other clinical characteristics, including dose and duration, were similar between groups. CONCLUSION: A response to steroids before surgery is highly predictive of long-term improvement postoperatively in brain metastasis patients with focal neurological deficits. Lack of a response portends a somewhat less favorable prognosis. Duration and intensity of therapy do not seem to affect the likelihood of response.

Defining the Clival Recess Surgical Corridor and Clival Classification System for Approach to Sellar Pathology.

BACKGROUND: Sellar masses within the pars intermedius, bordered anteriorly by normal pituitary gland/stalk, and/or with ectatic cavernous carotid anatomy are challenging and high risk when approached through the endonasal standard direct/anterior sellar approach. This approach portends itself to a higher risk of pituitary gland/stalk injury and subtotal resection with the aforementioned anatomic variants. OBJECTIVE: To describe the indirect clival recess corridor approach to sellar lesions. This corridor is a "silent" point of access to lesions in this region endoscopically. While skull base teams may have used this approach to some degree, it has not yet been described in the literature to our knowledge. METHODS: We defined the clival recess surgical corridor with skull base craniometric measurements and use a case example with aberrant anatomy to illustrate the approach. We cross-sectionally reviewed 42 patients with sellar and suprasellar masses. To describe the approach's anatomy, we devised and defined the terms dorsum sella plumb line, anatomic corridor, angle of osseous, and operative corridor. RESULTS: Created novel clival aeration grade informing surgical planning. Classified clival aeration as Grade 1 (100%-75% aeration), Grade 2 (75%-50% aeration), Grade 3 (50%-25% aeration), and Grade 4 (25%-0% aeration). This classification system determines extent of drilling of the clivus required to optimize the clival recess corridor approach and its limitations. CONCLUSION: The clival recess surgical corridor is effective for accessing pituitary lesions within the sella. Consider the indirect approach when a standard direct/anterior sellar approach has high risk for vascular injury and/or endocrinological dysfunction.

A Method of Intraoperative Registration Verification to Prevent Accuracy Errors in Robot-Assisted Stereotactic Electroencephalography Electrode Placement.

BACKGROUND: Robotic-assisted stereotactic electroencephalography (sEEG) electrode placement is increasingly common at specialized epilepsy centers. High accuracy and low complication rates are essential to realizing the benefits of sEEG surgery. The aim of this study was to describe for the first time in the literature a method for a stereotactic registration checkpoint to verify intraoperative accuracy during robotic-assisted sEEG and to report our institutional experience with this technique. METHODS: All cases performed with this technique since the adoption of robotic-assisted sEEG at our institution were retrospectively reviewed. RESULTS: In 4 of 111 consecutive sEEG operations, use of the checkpoint detected an intraoperative registration error, which was addressed before completion of sEEG electrode placement. CONCLUSIONS: The use of a registration checkpoint in robotic-assisted sEEG surgery is a simple technique that can prevent electrode misplacement and improve the safety profile of this procedure.

Developing Data-Rich Video of Surface Water-Groundwater Interactions for Public Engagement.

Communication of hydrologic data to the public can be improved by connecting data to the places they represent. In our example of data communication, we coupled hydrologic data with simultaneously collected video as both a scientific and public engagement tool. This note presents a method for collecting spatially and temporally dense datasets of water-quality and geophysical data on small streams and lakes, and for displaying the data in a user-friendly format using commercially available software. With this method, multiple instruments are mounted on a canoe and a controlled survey float is carried out to collect data. The data stream is georeferenced and logged using an Arduino microcontroller to provide detailed information about spatial variability. We employed these continuous data-collection methods at small streams and lakes across Wisconsin, USA. Comparison of stream-float sensor data to lab reported data, data collected by alternative sensors, and previously collected data in our study areas indicates that the low-cost temperature, electrical conductivity, pH, and dissolved oxygen sensors performed well. GoPro cameras recorded video throughout the duration of data collection. Our established water-quality and geophysical data collection methods are inexpensive, fast, and reliable, which qualify them as excellent tools for fine-scale spatial understanding of stream and lake habitats' health. Data-rich video connects point measurements of water properties to the appearance of the native environment. This method helps improve our understanding of groundwater and surface water interactions in complex hydrogeologic systems, enhance communication amongst stakeholders, and provide context when monitoring and managing sensitive habitats.

Stealth Autoguide for robotic-assisted laser ablation for lesional epilepsy: illustrative case.

BACKGROUND: Laser interstitial thermal therapy has been used in tumor and epilepsy surgery to maximize clinical treatment impact while minimizing morbidity. This intervention places a premium on accuracy. With the advent of robotics, neurosurgery is entering a new age of improved accuracy. Here, the authors described the use of robotic-assisted laser placement for the treatment of epileptiform lesions. OBSERVATIONS: The authors presented a case of a 21-year-old woman with medically intractable epilepsy, localized to left mesial temporal sclerosis and left temporal encephalocele by way of stereotactic electroencephalography, who presented for consideration of surgical intervention. When presented with resection versus laser ablation, the patient opted for laser ablation. The patient received robotic-assisted stereotactic laser ablation (RASLA) using a Stealth Autoguide. The patient was seizure free (10 weeks) after surgical ablation. LESSONS: RASLA is an effective way to treat epilepsy. Here, the authors reported the first RASLA procedure with a Stealth Autoguide to treat epilepsy. The procedure can be performed effectively and efficiently for multiple epileptic foci without the need for bulkier robotic options or head frames that may interfere with the use of magnetic resonance imaging for heat mapping.

Neurological emergency from rare spinal metalloma: Case report and literature review.

Metallosis is a rare and poorly understood long-term complication of instrumented surgery that can result in an inflammatory pseudotumor termed metalloma. We describe a particularly unique case and compare it to 6 analogous cases identified by PubMed and/or Medline search through July 2020. A 79-year-old male with multiple prior spinal lumbar fusion procedures presented with progressive weakness and pain. Imaging revealed a large mass surrounding the right-sided paraspinal rod with extension into the spinal canal, neural foramina, extraforaminal spaces, psoas muscle, marrow spaces, and right sided pedicles. The case presented is a unique example of a unilateral metalloma with mixed-metal instrumentation that created a progressive neurologic deficit without infection, pseudoarthrosis, or hardware failure. This case highlights the lack of understanding regarding the pathophysiology of metallosis and metalloma in spinal instrumentation. We highlight the imaging findings of metalloma to encourage early identification for removal and decompression.

Optimal timing of radiotherapy following brain metastases surgery.

Background: There is growing evidence supporting the need for a short time delay before starting radiotherapy (RT) treatment postsurgery for most optimal responses. The timing of RT initiation and effects on outcomes have been evaluated in a variety of malignancies, but the relationship remains to be well established for brain metastasis. Methods: Retrospective study of 176 patients (aged 18-89 years) with brain metastases at a single institution (March 2009 to August 2018) who received RT following surgical resection. Time interval (≤22 and >22 days) from surgical resection to initiation of RT and any potential impact on patient outcomes were assessed. Results: Patients who underwent RT >22 days after surgical resection had a decreased risk for all-cause mortality of 47.2% (95% CI: 8.60, 69.5%). Additionally, waiting >40 days for RT after surgical resection more than doubled the risk of tumor progression; adjusted hazard ratio 2.02 (95% CI: 1.12, 3.64). Conclusions: Findings indicate that a short interval delay (>22 days) following surgical resection is required before RT initiation for optimal treatment effects in brain metastasis. Our timing of RT postsurgical resection data adds definition to current heterogeneity in RT timing, which is especially important for standardized clinical trial design and patient outcomes.