Improving Quality Care and Patient Safety With Implementation of an Oversew Stitch in Lumbar Drains.

ABSTRACT: The lumbar drain exit site purse string oversew stitch is a well-described bedside intervention to stop or prevent cerebrospinal fluid (CSF) leak. It is not routinely placed at the time of lumbar drain placement. Via four plan-do-study-act (PDSA) cycles, we test the effect of prophylactic utilization of the lumbar drain exit site oversew stitch on house officers' paging burden, need to redress the drain, need to oversew the drain to stop a CSF leak, and need to replace the drain. We found that the simple act of placing an oversew stitch at the time of lumbar drain placement significantly reduced paging burden and reduced the frequency at which an oversew stitch was required to stop a CSF leak. Subjectively, during PDSA cycles during which overstitches were placed prophylactically, in-house residents perceived that there were less lumbar drains on service, although objectively, the overall number was unchanged. We conclude that prophylactic lumbar drain exit site stitch placement reduces risk and bedside interventions for patients and also reduces overall call burden on house officers. This simple intervention may therefore provide a more widespread improvement in care quality beyond lumbar drain care because house officers experience less burnout during their call shifts.

Modular Phoneme Processing in Human Superior Temporal Gyrus.

Modular organization is fundamental to cortical processing, but its presence is human association cortex is unknown. We characterized phoneme processing with 128-1024 channel micro-arrays at 50-200µm pitch on superior temporal gyrus of 7 patients. High gamma responses were highly correlated within ~1.7mm diameter modules, sharply delineated from adjacent modules with distinct time-courses and phoneme-selectivity. We suggest that receptive language cortex may be organized in discrete processing modules.

Intraoperative application and early experience with novel high-resolution, high-channel-count thin-film electrodes for human microelectrocorticography.

OBJECTIVE: The study objective was to evaluate intraoperative experience with newly developed high-spatial-resolution microelectrode grids composed of poly(3,4-ethylenedioxythiophene) with polystyrene sulfonate (PEDOT:PSS), and those composed of platinum nanorods (PtNRs). METHODS: A cohort of patients who underwent craniotomy for pathological tissue resection and who had high-spatial-resolution microelectrode grids placed intraoperatively were evaluated. Patient demographic and baseline clinical variables as well as relevant microelectrode grid characteristic data were collected. The primary and secondary outcome measures of interest were successful microelectrode grid utilization with usable resting-state or task-related data, and grid-related adverse intraoperative events and/or grid dysfunction. RESULTS: Included in the analysis were 89 cases of patients who underwent a craniotomy for resection of neoplasms (n = 58) or epileptogenic tissue (n = 31). These cases accounted for 94 grids: 58 PEDOT:PSS and 36 PtNR grids. Of these 94 grids, 86 were functional and used successfully to obtain cortical recordings from 82 patients. The mean cortical grid recording duration was 15.3 ± 1.15 minutes. Most recordings in patients were obtained during experimental tasks (n = 52, 58.4%), involving language and sensorimotor testing paradigms, or were obtained passively during resting state (n = 32, 36.0%). There were no intraoperative adverse events related to grid placement. However, there were instances of PtNR grid dysfunction (n = 8) related to damage incurred by suboptimal preoperative sterilization (n = 7) and improper handling (n = 1); intraoperative recordings were not performed. Vaporized peroxide sterilization was the most optimal sterilization method for PtNR grids, providing a significantly greater number of usable channels poststerilization than did steam-based sterilization techniques (median 905.0 [IQR 650.8-935.5] vs 356.0 [IQR 18.0-597.8], p = 0.0031). CONCLUSIONS: High-spatial-resolution microelectrode grids can be readily incorporated into appropriately selected craniotomy cases for clinical and research purposes. Grids are reliable when preoperative handling and sterilization considerations are accounted for. Future investigations should compare the diagnostic utility of these high-resolution grids to commercially available counterparts and assess whether diagnostic discrepancies relate to clinical outcomes.

Responsive neurostimulation for treatment of pediatric refractory epilepsy: A pooled analysis of the literature.

BACKGROUND: Drug-resistant epilepsy (DRE) is a complex medical condition often requiring resective surgery and/or some form of neurostimulation. In recent years responsive neurostimulation (RNS) has shown promising results in adult DRE, however there is a paucity of information regarding outcomes of RNS among pediatric patients treated with DRE. In this individual patient data meta-analysis (IPDMA) we seek to elucidate the effects RNS has on the pediatric population. METHODS: Literature regarding management of pediatric DRE via RNS was reviewed in accordance with individual patient data meta-analysis guidelines. Four databases were searched with keywords ((Responsive neurostimulation) AND (epilepsy)) through December of 2022. From 1624 retrieved full text studies, 15 were ultimately included affording a pool of 98 individual participants. RESULTS: The median age at implantation was 14 years (n = 95) with 42% of patients having undergone prior resective epilepsy surgery, 18% with prior vagus nerve stimulation (VNS), and 1% with prior RNS. At a median follow up time 12 months, median percent seizure reduction was 75% with 57% of patients achieving Engel Class < 2 outcome, 9.7% of which achieved seizure freedom. We report a postoperative complication rate of 8.4%, half of which were device-related infections. Magnetic resonance imaging (MRI)-negative cases were negatively associated with magnitude of seizure reduction, and direct targeting techniques were associated with stronger treatment response when compared to other methods. CONCLUSIONS: This review suggests RNS to be an effective treatment modality for pediatric patients with a postoperative complication rate comparable to that of RNS in adults. Investigation of prognostic clinical variables should be undertaken to augment patient selection. Last, multi-institutional prospective study of long-term effects of RNS on pediatric patients would stand to benefit clinicians in the management of pediatric DRE.

Thalamic responsive neurostimulation for the treatment of refractory epilepsy: an individual patient data meta-analysis.

OBJECTIVE: In recent years, the treatment of drug-resistant epilepsy (DRE) has made greater use of surgery and expanded options for neurostimulation or neuromodulation. Up to this point, responsive neurostimulation (RNS) has been very promising but has mainly used only the cortex as a target. In this individual patient data meta-analysis (IPDMA), the authors sought to establish if a novel RNS target, the thalamus, can be used to treat DRE. METHODS: The literature regarding the management of DRE by targeting the thalamus with RNS was reviewed per IPDMA guidelines. Five databases were searched with keywords [((Responsive neurostimulation) OR (RNS)) AND ((thalamus) OR (thalamic) OR (Deep-seated) OR (Diencephalon) OR (limbic))] in March 2022. RESULTS: The median (interquartile range) age at implantation was 17 (13.5-27.5) years (n = 42) with an epilepsy duration of 12.1 (5.8-15.3) years. In total, 52.4% of patients had previously undergone epilepsy surgery, 28.6% had prior vagus nerve stimulation, and 2.4% had prior RNS. The median preimplant seizure frequency was 12 per week. The median seizure reduction at last follow-up was 73%. No study in this IPDMA reported complications, although 7 cases (16.3%) did require reoperation. Behavioral improvements and reduced antiepileptic drug dose or quantity were reported for 80% and 28.6% of patients, respectively. CONCLUSIONS: This review indicates that thalamic RNS may be safe and effective for treating DRE. Long-term and controlled studies on thalamic RNS for DRE would further elucidate this technique's potential benefits and complications and help guide clinical judgment in the management of DRE.

How does discharge against medical advice affect risk of mortality and unplanned readmission? A retrospective cohort study set in a large UK medical admissions unit.

OBJECTIVES: To assess the frequency of discharge against medical advice (DAMA) in a large UK teaching hospital, explore factors which increase the risk of DAMA and identify how DAMA impacts patient risk of mortality and readmission. DESIGN: Retrospective cohort study. SETTING: Large acute teaching hospital in the UK. PATIENTS: 36 683 patients discharged from the acute medical unit of a large UK teaching hospital between 1 January 2012 and 31 December 2016. MEASUREMENTS: Patients were censored on 1 January 2021. Mortality and 30-day unplanned readmission rates were assessed. Deprivation, age and sex were taken as covariates. RESULTS: 3% of patients discharged against medical advice. These patients were younger (median age (years) (IQR)): planned discharge (PD) 59 (40-77); DAMA 39 (28-51), predominantly of male sex (PD 48%; DAMA 66%) and were of greater social deprivation (in three most deprived quintiles PD 69%; DAMA 84%). DAMA was associated with increased risk of death in patients under the age of 33.3 years (adjusted HR 2.6 (1.2-5.8)) and increased incidence of 30-day readmission (standardised incidence ratio 1.9 (1.5-2.2)). LIMITATIONS: Readmission to acute hospitals outside of the local health board may have been missed. We were unable to include information regarding comorbidity or severity of presentation. CONCLUSIONS: These data highlight the vulnerability of younger patients who DAMA, even in a free-at-the-point-of-delivery healthcare setting.

Advancing convergence research: Renewable energy solutions for off-grid communities.

Millions of people across the world live off-grid not by choice but because they live in rural areas, have low income, and have no political clout. Delivering sustainable energy solutions to such a substantial amount of the world's population requires more than a technological fix; it requires leveraging the knowledge of underserved populations working together with a transdisciplinary team to find holistically derived solutions. Our original research has resulted in an innovative Convergence Framework integrating the fields of engineering, social sciences, and communication, and is based on working together with communities and other stakeholders to address the challenges posed by delivering clean energy solutions. In this paper, we discuss the evolution of this Framework and illustrate how this Framework is being operationalized in our on-going research project, cocreating hybrid renewable energy systems for off-grid communities in the Brazilian Amazon. The research shows how this Framework can address clean energy transitions, strengthen emerging industries at local level, and foster Global North-South scholarly collaborations. We do so by the integration of social science and engineering and by focusing on community engagement, energy justice, and governance for underserved communities. Further, this solution-driven Framework leads to the emergence of unique approaches that advance scientific knowledge, while at the same time addressing community needs.

Repeat surgery for pediatric epilepsy: a systematic review and meta-analysis of resection and disconnection approaches.

OBJECTIVE: Resection and disconnection surgeries for epilepsy in the pediatric demographic (patients ≤ 18 years of age) are two separate, definitive intervention options in medically refractory cases. Questions remain regarding the role of surgery when seizures persist after an initial incomplete surgery. The aim of this study was to review the contemporary literature and summarize the metadata on the outcomes of repeat surgery in this specific demographic. METHODS: Searches of seven electronic databases from inception to July 2022 were conducted using PRISMA guidelines. Articles were screened using prespecified criteria. Metadata from the articles were abstracted and pooled by random-effects meta-analysis of proportions. RESULTS: Eleven studies describing 12 cohorts satisfied all criteria, reporting outcomes of 170 pediatric patients with epilepsy who underwent repeat resection or disconnection surgery. Of these patients, 55% were male, and across all studies, median ages at initial and repeat surgeries were 7.2 and 9.4 years, respectively. The median follow-up duration after repeat surgery was 47.7 months. The most commonly reported etiology for epilepsy was cortical dysplasia. Overall, the estimated incidence of complete seizure freedom (Engel class I) following repeat surgery was 48% (95% CI 40%-56%, p value for heterogeneity = 0.93), and the estimated incidence of postoperative complications following repeat surgery was 25% (95% CI 12%-39%, p = 0.04). There were six cohorts each that described outcomes for repeat resection and repeat disconnection surgeries. There was no statistical difference between these two subgroups with respect to estimated incidence of complete seizure freedom (p value for interaction = 0.92), but postoperative complications were statistically more common following repeat resection (p ≤ 0.01). CONCLUSIONS: For both resection and disconnection surgeries, repeat epilepsy surgery in children is likely to confer complete seizure freedom in approximately half of the patients who experience unsuccessful initial incomplete epilepsy surgery. More data are needed to elucidate the impact on efficacy based on surgical approach selection. Judicious discussion and planning between the patient, family, and a multidisciplinary team of epilepsy specialists is recommended to optimize expectations and outcomes in this setting.

Pleistocene climate variability in eastern Africa influenced hominin evolution.

Despite more than half a century of hominin fossil discoveries in eastern Africa, the regional environmental context of hominin evolution and dispersal is not well established due to the lack of continuous palaeoenvironmental records from one of the proven habitats of early human populations, particularly for the Pleistocene epoch. Here we present a 620,000-year environmental record from Chew Bahir, southern Ethiopia, which is proximal to key fossil sites. Our record documents the potential influence of different episodes of climatic variability on hominin biological and cultural transformation. The appearance of high anatomical diversity in hominin groups coincides with long-lasting and relatively stable humid conditions from ~620,000 to 275,000 years bp (episodes 1-6), interrupted by several abrupt and extreme hydroclimate perturbations. A pattern of pronounced climatic cyclicity transformed habitats during episodes 7-9 (~275,000-60,000 years bp), a crucial phase encompassing the gradual transition from Acheulean to Middle Stone Age technologies, the emergence of Homo sapiens in eastern Africa and key human social and cultural innovations. Those accumulative innovations plus the alignment of humid pulses between northeastern Africa and the eastern Mediterranean during high-frequency climate oscillations of episodes 10-12 (~60,000-10,000 years bp) could have facilitated the global dispersal of H. sapiens.

Constructing 2D maps of human spinal cord activity and isolating the functional midline with high-density microelectrode arrays.

Intraoperative neuromonitoring (IONM) is a widely used practice in spine surgery for early detection and minimization of neurological injury. IONM is most commonly conducted by indirectly recording motor and somatosensory evoked potentials from either muscles or the scalp, which requires large-amplitude electrical stimulation and provides limited spatiotemporal information. IONM may inform of inadvertent events during neurosurgery after they occur, but it does not guide safe surgical procedures when the anatomy of the diseased spinal cord is distorted. To overcome these limitations and to increase our understanding of human spinal cord neurophysiology, we applied a microelectrode array with hundreds of channels to the exposed spinal cord during surgery and resolved spatiotemporal dynamics with high definition. We used this method to construct two-dimensional maps of responsive channels and define with submillimeter precision the electrophysiological midline of the spinal cord. The high sensitivity of our microelectrode array allowed us to record both epidural and subdural responses at stimulation currents that are well below those used clinically and to resolve postoperative evoked potentials when IONM could not. Together, these advances highlight the potential of our microelectrode arrays to capture previously unexplored spinal cord neural activity and its spatiotemporal dynamics at high resolution, offering better electrophysiological markers that can transform IONM.

Plio-Pleistocene environmental variability in Africa and its implications for mammalian evolution.

Understanding the climatic drivers of environmental variability (EV) during the Plio-Pleistocene and EV's influence on mammalian macroevolution are two outstanding foci of research in African paleoclimatology and evolutionary biology. The potential effects of EV are especially relevant for testing the variability selection hypothesis, which predicts a positive relationship between EV and speciation and extinction rates in fossil mammals. Addressing these questions is stymied, however, by 1) a lack of multiple comparable EV records of sufficient temporal resolution and duration, and 2) the incompleteness of the mammalian fossil record. Here, we first compile a composite history of Pan-African EV spanning the Plio-Pleistocene, which allows us to explore which climatic variables influenced EV. We find that EV exhibits 1) a long-term trend of increasing variability since ∼3.7 Ma, coincident with rising variability in global ice volume and sea surface temperatures around Africa, and 2) a 400-ky frequency correlated with seasonal insolation variability. We then estimate speciation and extinction rates for fossil mammals from eastern Africa using a method that accounts for sampling variation. We find no statistically significant relationship between EV and estimated speciation or extinction rates across multiple spatial scales. These findings are inconsistent with the variability selection hypothesis as applied to macroevolutionary processes.

Human brain mapping with multithousand-channel PtNRGrids resolves spatiotemporal dynamics.

Electrophysiological devices are critical for mapping eloquent and diseased brain regions and for therapeutic neuromodulation in clinical settings and are extensively used for research in brain-machine interfaces. However, the existing clinical and experimental devices are often limited in either spatial resolution or cortical coverage. Here, we developed scalable manufacturing processes with a dense electrical connection scheme to achieve reconfigurable thin-film, multithousand-channel neurophysiological recording grids using platinum nanorods (PtNRGrids). With PtNRGrids, we have achieved a multithousand-channel array of small (30 µm) contacts with low impedance, providing high spatial and temporal resolution over a large cortical area. We demonstrated that PtNRGrids can resolve submillimeter functional organization of the barrel cortex in anesthetized rats that captured the tissue structure. In the clinical setting, PtNRGrids resolved fine, complex temporal dynamics from the cortical surface in an awake human patient performing grasping tasks. In addition, the PtNRGrids identified the spatial spread and dynamics of epileptic discharges in a patient undergoing epilepsy surgery at 1-mm spatial resolution, including activity induced by direct electrical stimulation. Collectively, these findings demonstrated the power of the PtNRGrids to transform clinical mapping and research with brain-machine interfaces.

Speech-related auditory salience detection in the posterior superior temporal region.

Processing auditory human speech requires both detection (early and transient) and analysis (sustained). We analyzed high gamma (70-110 Hz) activity of intracranial electroencephalography waveforms acquired during an auditory task that paired forward speech, reverse speech, and signal correlated noise. We identified widespread superior temporal sites with sustained activity responding only to forward and reverse speech regardless of paired order. More localized superior temporal auditory onset sites responded to all stimulus types when presented first in a pair and responded in recurrent fashion to the second paired stimulus in select conditions even in the absence of interstimulus silence; a novel finding. Auditory onset activity to a second paired sound recurred according to relative salience, with evidence of partial suppression during linguistic processing. We propose that temporal lobe auditory onset sites facilitate a salience detector function with hysteresis of 200 ms and are influenced by cortico-cortical feedback loops involving linguistic processing and articulation.

Feasibility of hybrid in-stream generator-photovoltaic systems for Amazonian off-grid communities.

While there have been efforts to supply off-grid energy in the Amazon, these attempts have focused on low upfront costs and deployment rates. These "get-energy-quick" methods have almost solely adopted diesel generators, ignoring the environmental and social risks associated with the known noise and pollution of combustion engines. Alternatively, it is recommended, herein, to supply off-grid needs with renewable, distributed microgrids comprised of photovoltaics (PV) and in-stream generators (ISG). Utilization of a hybrid combination of renewable generators can provide an energetically, environmentally, and financially feasible alternative to typical electrification methods, depending on available solar irradiation and riverine characteristics, that with community engagement allows for a participatory codesign process that takes into consideration people's needs. A convergent solution development framework that includes designers-a team of social scientists, engineers, and communication specialists-and communities as well as the local industry is examined here, by which the future negative impacts at the human-machine-environment nexus can be minimized by iterative, continuous interaction between these key actors.

Increased ecological resource variability during a critical transition in hominin evolution.

Although climate change is considered to have been a large-scale driver of African human evolution, landscape-scale shifts in ecological resources that may have shaped novel hominin adaptations are rarely investigated. We use well-dated, high-resolution, drill-core datasets to understand ecological dynamics associated with a major adaptive transition in the archeological record ~24 km from the coring site. Outcrops preserve evidence of the replacement of Acheulean by Middle Stone Age (MSA) technological, cognitive, and social innovations between 500 and 300 thousand years (ka) ago, contemporaneous with large-scale taxonomic and adaptive turnover in mammal herbivores. Beginning ~400 ka ago, tectonic, hydrological, and ecological changes combined to disrupt a relatively stable resource base, prompting fluctuations of increasing magnitude in freshwater availability, grassland communities, and woody plant cover. Interaction of these factors offers a resource-oriented hypothesis for the evolutionary success of MSA adaptations, which likely contributed to the ecological flexibility typical of Homo sapiens foragers.

Dural Arteriovenous Fistula Presenting as Trigeminal Neuralgia: 2 Case Reports and Review of the Literature.

BACKGROUND: Dural arteriovenous fistulae (dAVFs) can sporadically compress the root entry zone of the trigeminal nerve or the Gasserian ganglion and therefore be a rare cause of isolated or complicated trigeminal neuralgia (TN). CASE DESCRIPTION: We describe 2 cases of TN related to dAVF treated similarly with transarterial embolization but with divergent outcomes. Further, we completed a comprehensive literature review of previously reported cases to date. A sparse but growing literature with regards to this specific and rare but salient cause of TN was noted. The type of dAVF most commonly found to cause TN was that of a tentorial nidus, a lesion generally accepted to be at high risk of hemorrhage and in need of urgent treatment. This warrants imaging for new TN presentations to ensure that a dangerous lesion does not represent the underlying cause, especially when the TN symptoms are comorbid with other symptoms such as a bruit. Treatments pursued span the range of open surgery, endovascular treatment, and radiosurgery with great success in treating both the TN symptoms, as well as the rupture risk of the dAVF itself in most cases. Indeed, endovascular approaches are becoming more widely employed for these cases over time, often resolving the abnormality on first treatment attempt. Other cases reach resolution after employing a combination of treatment modalities. CONCLUSIONS: This work highlights that dAVFs, particularly the tentorial type, are capable of causing TN symptomatically identical to that of other etiologies and that treatment of the dAVF itself is often sufficient.

Four-dimensional functional cortical maps of visual and auditory language: Intracranial recording.

OBJECTIVE: The strength of presurgical language mapping using electrocorticography (ECoG) is its outstanding signal fidelity and temporal resolution, but the weakness includes limited spatial sampling at an individual patient level. By averaging naming-related high-gamma activity at nonepileptic regions across a large number of patients, we provided the functional cortical atlases animating the neural dynamics supporting visual-object and auditory-description naming at the whole brain level. METHODS: We studied 79 patients who underwent extraoperative ECoG recording as epilepsy presurgical evaluation, and generated time-frequency plots and animation videos delineating the dynamics of naming-related high-gamma activity at 70-110 Hz. RESULTS: Naming task performance elicited high-gamma augmentation in domain-specific lower-order sensory areas and inferior-precentral gyri immediately after stimulus onset. High-gamma augmentation subsequently involved widespread neocortical networks with left hemisphere dominance. Left posterior temporal high-gamma augmentation at several hundred milliseconds before response onset exhibited a double dissociation; picture naming elicited high-gamma augmentation preferentially in regions medial to the inferior-temporal gyrus, whereas auditory naming elicited high-gamma augmentation more laterally. The left lateral prefrontal regions including Broca's area initially exhibited high-gamma suppression subsequently followed by high-gamma augmentation at several hundred milliseconds before response onset during both naming tasks. Early high-gamma suppression within Broca's area was more intense during picture compared to auditory naming. Subsequent lateral-prefrontal high-gamma augmentation was more intense during auditory compared to picture naming. SIGNIFICANCE: This study revealed contrasting characteristics in the spatiotemporal dynamics of naming-related neural modulations between tasks. The dynamic atlases of visual and auditory language might be useful for planning of epilepsy surgery. Differential neural activation well explains some of the previously reported observations of domain-specific language impairments following resective epilepsy surgery. Video materials might be beneficial for the education of lay people about how the brain functions differentially during visual and auditory naming.

Surgical Parameters for Minimally Invasive Trans-Eustachian Tube CSF Leak Repair: A Cadaveric Study and Literature Review.

BACKGROUND: Cerebrospinal fluid rhinorrhea from a lateral skull base defect refractory to spontaneous healing and/or conservative management is most commonly managed via open surgery. Approach for repair is dictated by location of the defect, which may require surgical exploration. The final common pathway is the eustachian tube (ET). Endoscopic ET obliteration via endonasal and lateral approaches is under development. Whereas ET anatomy has been studied, surgical landmarks have not been previously described or quantified. We aimed to define surgical parameters of specific utility to endoscopic ET obliteration. METHODS: A literature review was performed of known ET anatomic parameters. Next, using a combination of endoscopic and open techniques in cadavers, we cannulated the intact ET and dissected its posterior component to define the major curvature position of the ET, defined as the genu, and quantified the relative distances through the ET lumen. The genu was targeted as a major obstacle encountered when cannulating the ET from the nasopharynx. RESULTS: Among 10 ETs, we found an average distance of 23 ± 5 mm from the nasopharynx to the ET genu, distance of 24 ± 3 mm from the genu to the anterior aspect of the tympanic membrane and total ET length of 47 ± 4 mm. CONCLUSIONS: Although membranous and petrous components of the ET are important to its function, the genu may be a more useful surgical landmark. Basic surgical parameters for endoscopic ET obliteration are defined.

Neural dynamics of verbal working memory in auditory description naming.

Auditory naming is suggested to require verbal working memory (WM) operations in addition to speech sound perception during the sentence listening period and semantic/syntactic processing during the subsequent judgement period. We attempted to dissect cortical activations attributable to verbal WM from those otherwise involved in answering auditory sentence questions. We studied 19 patients who underwent electrocorticography recordings and measured high-gamma activity during auditory naming and WM tasks. In the auditory naming task, inferior-precentral high-gamma activity was augmented during sentence listening, and the magnitude of augmentation was independently correlated to that during the WM task maintenance period as well as patient age. High-gamma augmentation during the WM task scanning period accounted for high-gamma variance during the naming task judgement period in some of the left frontal association neocortex regions (most significantly in the middle-frontal, less in the inferior-frontal, and least in the orbitofrontal gyrus). Inferior-frontal high-gamma augmentation was left-hemispheric dominant during naming task judgement but rather symmetric during WM scanning. Left orbitofrontal high-gamma augmentation was evident only during the naming task judgement period but minimal during the WM task scanning period. The inferior-precentral regions may exert WM maintenance during sentence listening, and such maintenance function may be gradually strengthened as the brain matures. The left frontal association neocortex may have a dorsal-to-ventral gradient in functional roles during naming task judgement. Namely, left middle-frontal activation may be well-attributable to WM scanning function, whereas left orbitofrontal activation may be attributable less to WM scanning but more largely to syntactic/semantic processing.

Minimally invasive endoscopic repair of refractory lateral skull base cerebrospinal fluid rhinorrhea: case report and review of the literature.

Cerebrospinal fluid (CSF) leaks occur in approximately 10% of patients undergoing a translabyrinthine, retrosigmoid, or middle fossa approach for vestibular schwannoma resection. Cerebrospinal fluid rhinorrhea also results from trauma, neoplasms, and congenital defects. A high degree of difficulty in repair sometimes requires repetitive microsurgical revisions-a rate of 10% of cases is often cited. This can not only lead to morbidity but is also costly and burdensome to the health care system. In this case-based theoretical analysis, the authors summarize the literature regarding endoscopic endonasal techniques to obliterate the eustachian tube (ET) as well as compare endoscopic endonasal versus open approaches for repair. Given the results of their analysis, they recommend endoscopic endonasal ET obliteration (EEETO) as a first- or second-line technique for the repair of CSF rhinorrhea from a lateral skull base source refractory to spontaneous healing and CSF diversion. They present a case in which EEETO resolved refractory CSF rhinorrhea over a 10-month follow-up after CSF diversions, wound reexploration, revised packing of the ET via a lateral microscopic translabyrinthine approach, and the use of a vascularized flap had failed. They further summarize the literature regarding studies that describe various iterations of EEETO. By its minimally invasive nature, EEETO imposes less morbidity as well as less risk to the patient. It can be readily implemented into algorithms once CSF diversion (for example, lumbar drain) has failed, prior to considering open surgery for repair. Additional studies are warranted to further demonstrate the outcome and cost-saving benefits of EEETO as the data until now have been largely empirical yet very hopeful. The summaries and technical notes described in this paper may serve as a resource for those skull base teams faced with similar challenging and otherwise refractory CSF leaks from a lateral skull base source.