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Oral e-Poster Presentations - Booth 2: Neuro-Oncology C (Imaging&Monitoring), September 27, 2023, 1:00 PM - 2:30 PM
Background: Repetitive TMS (rTMS) can be used to non-invasively map cortical language areas. Commonly, frequencies of 5-10 Hz are used to induce speech errors. We could recently show that frequencies of 30 and 50 Hz are advantageous to achieve higher reliability. However, high-frequent rTMS applied over perisylvian regions still suffer from limited tolerability. Using short-train or paired-pulse TMS (pp-TMS) might offer a good alternative to rTMS to interfere with speech production. In this study, we, therefore, compared 30 Hz rTMS to pp-TMS aiming at improved language mapping.
Methods: 13 healthy, right-handed subjects (f=6, 25-41 years) were investigated using two different rTMS protocols: (i) 30 Hz rTMS and (ii) pp-TMS. TMS protocols were applied in a pseudo-randomized order during a picture naming task (picture-to-trigger interval: 0 ms) over cortical language areas. In a subsequent study, we compared pp-TMS also to short trains of three TMS pulses and repetitive paired pulse TMS. Language errors were post-hoc analysed by two independent raters and were assigned to eight different error categories. The level of pain was assessed on a subjective 0-10 numeric rating scale (NRS). Moreover, language error distribution was analysed using a cortical parcellation system.
Results: 30 Hz rTMS evoked a significantly higher number of errors than the pp-protocol, i.e., 18 ± 12 % vs. 10 ± 7 % (p<0.05). However, pp-TMS was significantly better tolerated with a mean NRS of 2.3 ± 1.6 vs. 3.4 ± 1.5 (p<0.05, FDR-corrected). Of note, pp-TMS could induce a higher number of anomias (15 ± 15 %) than repetitive TMS protocols (4 ± 7 %; p<0.1, FDR-corrected), but less dysarthria. The cortical distribution of errors differed between the two protocols. The results of train-of-three TMS were similar to the pp-TMS protocol.
Conclusions: Due to its better tolerability, pp-TMS might offer the possibility to stimulate regions which are particularly prone to direct facial / trigeminal nerve stimulation, e.g., the inferior frontal gyrus. Moreover, pp-TMS seems advantageous for mapping patients who are comparatively susceptible to rTMS side effects and with regard to safety in general.
TRENTOOL : an open source toolbox to estimate neural directed interactions with transfer entropy
(2011)
To investigate directed interactions in neural networks we often use Norbert Wiener's famous definition of observational causality. Wiener’s definition states that an improvement of the prediction of the future of a time series X from its own past by the incorporation of information from the past of a second time series Y is seen as an indication of a causal interaction from Y to X. Early implementations of Wiener's principle – such as Granger causality – modelled interacting systems by linear autoregressive processes and the interactions themselves were also assumed to be linear. However, in complex systems – such as the brain – nonlinear behaviour of its parts and nonlinear interactions between them have to be expected. In fact nonlinear power-to-power or phase-to-power interactions between frequencies are reported frequently. To cover all types of non-linear interactions in the brain, and thereby to fully chart the neural networks of interest, it is useful to implement Wiener's principle in a way that is free of a model of the interaction [1]. Indeed, it is possible to reformulate Wiener's principle based on information theoretic quantities to obtain the desired model-freeness. The resulting measure was originally formulated by Schreiber [2] and termed transfer entropy (TE). Shortly after its publication transfer entropy found applications to neurophysiological data. With the introduction of new, data efficient estimators (e.g. [3]) TE has experienced a rapid surge of interest (e.g. [4]). Applications of TE in neuroscience range from recordings in cultured neuronal populations to functional magnetic resonanace imaging (fMRI) signals. Despite widespread interest in TE, no publicly available toolbox exists that guides the user through the difficulties of this powerful technique. TRENTOOL (the TRansfer ENtropy TOOLbox) fills this gap for the neurosciences by bundling data efficient estimation algorithms with the necessary parameter estimation routines and nonparametric statistical testing procedures for comparison to surrogate data or between experimental conditions. TRENTOOL is an open source MATLAB toolbox based on the Fieldtrip data format. ...
Einleitung: Für die meisten Patienten mit HCC ist die LTX die einzige kurative Behandlungsoption. Bei diesen Patienten scheint eine Kontrolle der Erkrankung durch lokale Verfahren im Intervall bis zur LTX zu erreichen zu sein. Als das beste Verfahren gilt die transarterielle Chemoembolisation (TACE). Die Effektivität ist jedoch umstritten. Möglicherweise kann sie aber Patienten startifizieren, die ein hohes Rezidivrisiko haben.
Material und Methoden: Im Zeitraum zwischen 1995 und 2005 wurden n=27 Patienten mit HCC im Alter zwischen 22 und 69 Jahren transplantiert. Hiervon erhielten n=15 Patienten eine Vorbehandlung in Form einer alleinigen TACE oder kombiniert mit PEI [n=1] bzw. LITT [n=1]. Retrospektiv wurde das Gesamtüberleben sowie das „Event-free-survival“ (Rezidiv, Reinfektion und Tod) analysiert.
Ergebnisse: Die mittlere Wartezeit betrug bei Patienten in der TACE-Gruppe 214 Tage, bei Patienten ohne Vorbehandlung 133 Tage. Bei einem mittleren Nachbeobachtungszeitraum von 1097 ± 1193 Tagen für TACE-Patienten und 1674 ± 966 Tagen für non-TACE-Patienten betrug das Überleben für Patienten, die mit TACE vorbehandelt wurden 83,3%, für Patienten, die keine TACE erhielten 86.7% (p=0,5693). Gleiches fand sich für das Event-free-survival (p=0,8823). Das Gesamtüberleben der Patienten, die auf der Warteliste einen Tumorprogress hatten lag bei 77%, während Patienten mit stabiler Tumorgröße oder Regredienz der Tumore ein Überleben von 93% aufwiesen (p=0,0153). Unter TACE-Behandlung zeigten 5/15 Patienten eine zunehmende Anzahl an Herden im histologischen Präparat verglichen mit der Ausgangsbildgebung. Nur bei einem Patienten zeigte sich der Progress der Erkrankung bereits in der präoperativen Bildgebung. Patienten mit einem Progress der Erkrankung hatten ein Gesamtüberleben von 60%, während Patienten mit „stable disease“ oder Rückgang der Herde ein Gesamtüberleben von 100% hatten (p=0,0180).
Schlussfolgerung: Unseren Ergebnisse zufolge ist der Effekt der TACE als Bridgingverfahren auf das Überleben der Patienten fraglich. Allerdings scheint die TACE zur Riskostratifizierung geeignet zu sein. In unserem Patientenkollektiv hatten Patienten, die eine Progredienz der Erkrankung auf der Warteliste zeigten ein signifikant schlechteres Gesamtüberleben. Dies gilt auch bei ausschließlicher Betrachtung der Patienten mit TACE.
Hintergrund: Die praktische Anwendung der EbM bedarf neben interner Evidenz auch einiger Basis-Fertigkeiten, die schon während der medizinischen Ausbildung trainiert werden sollten. Während die EbM seit über 3 Jahren fester Bestandteil des Ausbildungscurriculums der medizinischen Fakultät in Frankfurt/Main ist, findet sie an vielen anderen Fakultäten nur langsam Einzug.
Um diesen Prozess zu unterstützen und zu beschleunigen, wurde von der Arbeitsgruppe EBM Frankfurt das Ausbildungskonzept Train the Teacher ins Leben gerufen.
Methoden: Der Train the Teacher-Kurs besteht aus zwei Teilen und basiert auf den Erfahrungen von 20 Basiskursen und über 50 curricularen Seminaren an der Universität Frankfurt. Er setzt sich aus einem „EbM-Aufbaukurs“ und einem „Didaktik-Kurs“ zusammen. Ziel des Kurses ist die Befähigung der Teilnehmer zur Konzeption eines eigenen EbM-Lehrangebotes an der jeweiligen Ausbildungseinrichtung. Beide Ausbildungsteile werden sowohl subjektiv als auch objektiv evaluiert.
Ergebnisse: Es konnten im Rahmen des Lehrkonzepts Train the Teacher mittlerweile 25 Personen aus unterschiedlichsten Fachbereichen und Einrichtungen aus dem gesamten Bundesgebiet ausgebildet werden. Sowohl die subjektiven als auch objektiven Evaluationen fallen durchweg positiv aus. Die Vorevaluation ergab bei der subjektiven Bewertung einen Score von 8,27 (Skala von 1 bis maximal 10). Bei der objektiven Evaluation wurden im Mittel 84% der gestellten Fragen richtig beantwortet.
Schlussfolgerung/Implikation: Der Train the Teacher – Kurs ist für das angestrebte Ziel Erfolg versprechend. Einige Absolventen haben bereits begonnen, an verschiedenen Ausbildungsstandorten evidenzbasierte Lehrangebote zu implementieren. Das Konzept wird erweitert und fortgeführt.
Introduction: Spondylodiscitis is the commonest form of infectious disease of the spine and harbours a high mortality rate of up to 20%. Recent demographic trends in Germany, such as an aging population, immunosuppression, and intravenous drug use, suggest that the incidence of spondylodiscitis may be on the rise. However, the exact epidemiological development of the disease remains uncertain. This study aims to analyse the burden on the tertiary healthcare system in Germany using data from the Federal Statistical Office of Germany (FSOG) database.
Materials and Methods: All cases of spondylodiscitis diagnosed between 2005 and 2021 were identified from the FSOG database. The study characterised the mean duration of hospital stays, total and population-adjusted number of diagnoses made, age-stratified incidence, and outcomes of hospitalised patients.
Results: A total of 131,982 diagnoses for spondylodiscitis were identified between 2005 and 2021. The number of diagnoses for spondylodiscitis has doubled during this period, from 5.4/100,000 population in 2005 to 11/100,000 population in 2021. The highest increase in admissions was recorded for those aged 90 years and above (+1307%), 80-89 (+376%) and 70-79 (+99%). Hospital discharges to rehabilitation facilities have increased by 160%, and discharges against medical advice by 91%. On the other hand, during the analysed period, the in-hospital mortality rate has decreased by 52%.
Conclusion: The population-adjusted incidence of spondylodiscitis in Germany has more than doubled between 2005 and 2021, highlighting the clinical relevance of this disease. During the same period, in-hospital mortality dropped by half. These findings suggest the need for further investigation into optimal therapy, particularly the role and timing of surgical treatment.
Introduction: Ferroptosis has recently been identified as a form of programmed cell death caused by an accumulation of lipid reactive oxygen species (ROS). However, little is yet known about the role in hepatocellular carcinoma (HCC) and its signalling mechanism as well the modulation of ROS.
Material and methods: Human HCC cell lines were treated with different concentrations of ROS modulators (Auranofin, Erastin, BSO). Cell death was determined by analysis of PI-stained nuclei using flow cytometry. ROS production and lipid peroxidation were analysed at early time points before cell death starts. For mechanistic studies we performed Western Blot and a Proteome array. Different inhibitors of cell death target proteins, ROS-scavengers as well as lipoxygenase inhibitors were used. To investigate the functional relevance of NAPDH oxidases (NOX) 1 and 4 for ROS modulation and ferroptosis we genetically silenced its genes using three distinct siRNAs and we used the NOX1/4-inhibitor GKT137831.
Results and discussions: Compared to the single treatment, Auranofin/BSO-cotreatment as well as Erastin/BSO-cotreatment acted in concert to trigger cell death and to reduce cell viability of HCC cells in a dose- and time-dependent manner. Furthermore, both cotreatments induce ROS production, lipid peroxidation and ferroptotic cell death, which could be inhibited by the use of Ferrostatin-1 (inhibitor of lipid peroxidation) and Liproxstatin-1 (specific inhibitor of ferroptosis). The broad-range caspase inhibitor zVAD.fmk failed to rescue cells from Auranofin/BSO- or Erastin/BSO-cotreatment induced cell death. No activation of caspases-3 could be seen in the proteome profiler apoptosis assay. Importantly, the selective lipoxygenase (LOX) inhibitor Baicalain and the pan-LOX inhibitor NDGA protect HCC cells from Auranofin/BSO- and Erastin/BSO-cotreatment stimulated lipid peroxidation, ROS generation and cell death, indication that the induction of ferroptosis may bypass apoptosis resistance of HCC cells. Mechanistic studies showed that Auranofin/BSO-cotreatment decreased TrxR-activity, led to Nrf2 accumulation and promoted the activation of HO-1. In contrast, NOX 1 and 4 were involved in Erastin/BSO-mediated cell death and the use of the NOX1/4-inhibitor GKT137831 rescued HCC cells from the Erastin/BSO-induced cell death.
Conclusion: By providing new insights into the molecular regulation of ROS and ferroptosis, our study contributes to the development of novel treatment strategies to reactivate programmed cell death in HCC cells.
Study Design: Cross-sectional survey
Objective: To determine the influence of surgeons’ level of experience and subspeciality training on the reliability, reproducibility, and accuracy of sacral fracture classification using the AO Spine Sacral Injury Classification System.
Summary of Background Data: An ideal classification system is easily comprehensible and reliable amongst the diverse group of surgeons. A surgeons’ level of experience may have a significant effect on the reliability and accuracy of a classification system. Moreover, surgeons of different subspecialities may have various levels of comfort with imaging assessment of sacral injuries required for accurate diagnosis and classification.
Methods: High-resolution computerized tomography (CT) images from 26 cases were assessed by 172 investigators from a diverse array of surgical subspecialities (general orthopaedics, neurosurgery, orthopaedic spine, orthopaedic trauma) and experience (<5, 5-10, 11-20, >20 years). Validation assessments were performed via web conference using high-resolution images, as well as axial/sagittal/coronal CT scan sequences. Two assessments were performed by each investigator independently three weeks apart in randomized order. Reliability and reproducibility were calculated with cohen’s kappa coefficient (k) and gold standard classification agreement was determined for each fracture morphology and subtype and stratified by experience and subspeciality.
Results: Respondents achieved an overall k = 0.87 for morphology and k = 0.77 for subtype classification, representing excellent and substantial intraobserver reproducibility, respectively. Respondents from all four practice experience groups demonstrated excellent interobserver reliability when classifying overall morphology (k=0.842/0.850, Assessment 1/Assessment 2) and substantial interobserver reliability in overall subtype (k=0.719/0.751) in both assessments. General orthopaedists, neurosurgeons, and orthopaedic spine surgeons exhibited excellent interobserver reliability in overall morphology classification and substantial interobserver reliability in overall subtype classification. Surgeons in each experience category and subspecialty correctly classified fracture morphology in over 90% of cases and fracture subtype in over 80% of cases according to the gold standard. Correct overall classification of fracture morphology (Assessment 1: p= 0.024, Assessment 2: p=0.006) and subtype (p2<0.001) differed significantly with surgeons with >20 years of experience demonstrating increased difficulty correctly classifying all fracture subtypes overall in comparison to the other experience groups. Correct overall classification did not significantly differ by subspecialty.
Conclusions: Overall, the AO Spine Sacral Injury Classification System appears to be universally applicable among surgeons of various subspecialties and levels of experience with acceptable reliability, reproducibility, and accuracy.
Disclosures: author 1: none; author 2: consultant=Medtronic, Nuvasive, ISD, Asutra, Stryker, Bioventus, Zimmer, teledocs, Clinical Spine Surgery, AOSpine ; author 3: none; author 4: grants/research support=AOSpine, consultant=DPS, icotec; author 5: none; author 6: none; author 7: grants/research support=DPS; author 8: none; author 9: grants/research support=NIH, RTI, CSRS, royalties=Inion ; author 10: stock/shareholder=Advanced Spinal Intellectual Properties; Atlas Spine; Avaz Surgical; Bonovo Orthopaedics; Computational Biodynamics; Cytonics; Deep Health; Dimension Orthotics LLC; Electrocore; Flagship Surgical; FlowPharma; Globus; Innovative Surgical Design; Insight Therapeutics; Jushi; Nuvasive; Orthobullets; Paradigm Spine; Parvizi Surgical Innovation; Progressive Spinal Technologies; Replication Medica; Spine Medica; Spineology; Stout Medical; Vertiflex; ViewFi Health, royalties=Aesculap; Atlas Spine; Globus; Medtronics; SpineWave; Stryker Spine,other financial report=AO Spine
Objective: Nationwide data on the epidemiology, treatment characteristics, and long-term outcome of severe traumatic brain injury (TBI) in Germany is not yet existing. Neurosurgeons from the German Neurosurgery Society (DGNC) and traumatologists from the German Trauma Society (DGU), therefore, joined forces in 2016 to conceptualize a TBI module for the well-established Trauma Register of the DGU (TR-DGU). Here, we report how this “German National TBI registry (GNTR)” has been developed, implemented, and tested in a recently completed pilot period.
Methods: The conception and implementation process of the GNTR from August 2016 to February 2019 is described, and results of its 23-months long pilot period from February 2019 to December 2020 are presented. For the pilot period, TBI patients were prospectively enrolled at nine neurosurgical and traumatological hospitals across Germany. Inclusion criteria were treatment on the ICU ≥ 24h, or an ISS score ≥ 16. A variety of clinical, imaging, and laboratory parameters were collected, and the GOSE score was used to assess the outcome at discharge and 6- and 12 months follow-up.
Results: Details on the structure and dataset of the GNTR as well as milestones and pitfalls during its conception and implementation, are outlined. During the pilot period, a total of 264 TBI patients were enrolled. Their demographic characteristics, clinical, imaging, and radiological findings, and their early mortality and functional outcome are described. Furthermore, factors associated with an unfavorable outcome (GOSE 1-4) are assessed using uni- and multivariate regression analyses. Finally, problems and future directions of the GNTR are discussed.
Conclusion: The pilot period of the GNTR offers a first glance at the current epidemiology and treatment characteristics of TBI patients in Germany. More importantly, they show how a national TBI registry yielding high-quality prospective data can be developed, implemented, and tested within four years