Redefining standards—response to: introductions of technological innovations in neurosurgery

<jats:title>Abstract</jats:title><jats:p>This paper presents radon flux profiles from four regions in Schleswig–Holstein (Northern Germany). Three of these regions are located over deep-rooted tectonic faults or salt diapirs and one is in an area without any tectonic or halokinetic activity, but with steep topography. Contrary to recently published studies on spatial patterns of soil radon gas concentration we measured flux of radon from soil into the atmosphere. All radon devices of each profile were deployed simultaneously to avoid inconsistencies due to strong diurnal variations of radon exhalation. To compare data from different seasons, values had to be normalized. Observed radon flux patterns are apparently related to the mineralogical composition of the Quaternary strata (particularly to the abundance of reddish granite and porphyry), and its grain size (with a flux maximum in well-sorted sand/silt). Minimum radon flux occurs above non-permeable, clay-rich soil layers. Small amounts of water content in the pore space increase radon flux, whereas excessive water content lessens it. Peak flux values, however, are observed over a deep-rooted fault system on the eastern side of Lake Plön, i.e., at the boundary of the Eastholstein Platform and the Eastholstein Trough. Furthermore, high radon flux values are observed in two regions associated with salt diapirism and near-surface halokinetic faults. These regions show frequent local radon flux maxima, which indicate that the uppermost strata above salt diapirs are very inhomogeneous. Deep-rooted increased permeability (effective radon flux depth) or just the boundaries between permeable and impermeable strata appear to concentrate radon flux. In summary, our radon flux profiles are in accordance with the published evidence of low radon concentrations in the “normal” soils of Schleswig–Holstein. However, very high values of radon flux are likely to occur at distinct locations near salt diapirism at depth, boundaries between permeable and impermeable strata, and finally at the tectonically active flanks of the North German Basin.</jats:p&gt

Zur Analyse pädagogischer Interaktion in reformierten Schuleingangsklassen anhand soziologischer Textinterpretation

Ausgangspunkt des Beitrags ist das bildungspolitische Ziel der Vergrößerung von Chancengleichheit, d.h. die Verbesserung der schulischen Erfolgschancen für Kinder aus den sozio-ökonomischen Unterschichten. Es werden der Hintergrund für die sogenannte deutsche Bildungskatastrophe und die daraus folgenden bildungspolitischen Reformen zu Beginn der 70er Jahre beschrieben. Mit dem Beispiel der Schuleingangsstufe (Schuleintritt mit 5 Jahren) wird ein Reformmodell für den Bereich Vorschulerziehung vorgestellt. Das Material für die vorliegende Analyse stammt aus Protokollen, die zu einer 1974 durchgeführten Untersuchung gehören, bei der in teilnehmender Beobachtung mit Tonbandaufzeichnung das Verhalten von 50 Kinder aus Berliner Eingangsstufen in nach sozio-ökonomischen Indikatoren kontrastierenden Einzugsgebieten analysiert wurde. Als Grundlage wird eine Szene aus einem Unterrichtsabschnitt dargestellt. Beginnend mit dem ersten Satz werden sämtliche protokollierten Interakte in der Reihenfolge ihres Auftretens kumulativ interpretiert. Die Interpretationen folgen dem Prinzip der extensiven Sinnauslegung, d.h. für jeden Interakt werden alle möglichen Bedeutungsgehalte expliziert. Dabei wird nicht nur der subjektiv gemeinte Sinn des Handelnden erschlossen. Es geht vor allem darum die objektiven, wenngleich in der Regel latent bleibenden Sinnstrukturen zu rekonstruieren. Damit werden die objektiven Beziehungsstrukturen zwischen Lehrern und Schülern sowie der Schüler untereinander erfaßt. Die Textinterpretation ist auf die Frage zugeschnitten, inwiefern die progressive pädagogische Interaktion dem Ziel der kompensatorischen Erziehung gerecht wird. (RW

Augmented reality visualization in brain lesions: a prospective randomized controlled evaluation of its potential and current limitations in navigated microneurosurgery

Background: Augmented reality (AR) has the potential to support complex neurosurgical interventions by including visual information seamlessly. This study examines intraoperative visualization parameters and clinical impact of AR in brain tumor surgery. Methods: Fifty-five intracranial lesions, operated either with AR-navigated microscope (n = 39) or conventional neuronavigation (n = 16) after randomization, have been included prospectively. Surgical resection time, duration/type/mode of AR, displayed objects (n, type), pointer-based navigation checks (n), usability of control, quality indicators, and overall surgical usefulness of AR have been assessed. Results: AR display has been used in 44.4% of resection time. Predominant AR type was navigation view (75.7%), followed by target volumes (20.1%). Predominant AR mode was picture-in-picture (PiP) (72.5%), followed by 23.3% overlay display. In 43.6% of cases, vision of important anatomical structures has been partially or entirely blocked by AR information. A total of 7.7% of cases used MRI navigation only, 30.8% used one, 23.1% used two, and 38.5% used three or more object segmentations in AR navigation. A total of 66.7% of surgeons found AR visualization helpful in the individual surgical case. AR depth information and accuracy have been rated acceptable (median 3.0 vs. median 5.0 in conventional neuronavigation). The mean utilization of the navigation pointer was 2.6 x /resection hour (AR) vs. 9.7 x /resection hour (neuronavigation); navigation effort was significantly reduced in AR (P < 0.001). Conclusions: The main benefit of HUD-based AR visualization in brain tumor surgery is the integrated continuous display allowing for pointer-less navigation. Navigation view (PiP) provides the highest usability while blocking the operative field less frequently. Visualization quality will benefit from improvements in registration accuracy and depth impression

Clinical implementation of a 3D4K-exoscope (Orbeye) in microneurosurgery

Exoscopic surgery promises alleviation of physical strain, improved intraoperative visualization and facilitation of the clinical workflow. In this prospective observational study, we investigate the clinical usability of a novel 3D4K-exoscope in routine neurosurgical interventions. Questionnaires on the use of the exoscope were carried out. Exemplary cases were additionally video-documented. All participating neurosurgeons (n = 10) received initial device training. Changing to a conventional microscope was possible at all times. A linear mixed model was used to analyse the impact of time on the switchover rate. For further analysis, we dichotomized the surgeons in a frequent (n = 1) and an infrequent (n = 9) user group. A one-sample Wilcoxon signed rank test was used to evaluate, if the number of surgeries differed between the two groups. Thirty-nine operations were included. No intraoperative complications occurred. In 69.2% of the procedures, the surgeon switched to the conventional microscope. While during the first half of the study the conversion rate was 90%, it decreased to 52.6% in the second half (p = 0.003). The number of interventions between the frequent and the infrequent user group differed significantly (p = 0.007). Main reasons for switching to ocular-based surgery were impaired hand-eye coordination and poor depth perception. The exoscope investigated in this study can be easily integrated in established neurosurgical workflows. Surgical ergonomics improved compared to standard microsurgical setups. Excellent image quality and precise control of the camera added to overall user satisfaction. For experienced surgeons, the incentive to switch from ocular-based to exoscopic surgery greatly varies