ernie del disco dorsali

L’ernia del disco rappresenta una patologia relativamente frequente, se considerati nel complesso i tre livelli spinali: cervicale, toracico e lombare. Tuttavia, se si studia l’incidenza dell’ernia discale a livello dei singoli tratti spinali, si scopre che nel tratto lombare si verificano il 90-95% dei casi d’ernia discale e in quello cervicale il 10-5% dei casi. Il tratto toracico, invece, contribuisce alla casistica globale delle ernie discali solo per l’1%. La patologia discale toracica rientra dunque nelle patologie definite come “rare”, avendo un’incidenza di circa 1 su un milione/anno. In realtà, la diffusione delle metodiche di imaging, come la TC e la RM ha messo in luce una prevalenza nella popolazione molto più alta: circa il 15% della popolazione sembra avere una protrusione o una vera e propria ernia a livello dei dischi dorsali. Si tratta, però, di casi che in medicina vengono definiti come “incidentalomi”, nel senso che la diagnosi delle ernie discali dorsali in questa grossa fetta della popolazione, non è stata guidata da un sospetto clinico di ernia dorsale, bensì i soggetti sono sottoposti a TC o RM per altre ragioni e nel corso dell’esame viene evidenziata la presenza dell’ernia. Inoltre, questa grossa fetta di popolazione “portatrice” dell’ernia discale dorsale sembra essere totalmente asintomatica. Invece, l’1% delle ernie discali toraciche sono sintomatiche e sono proprio queste che giungono all’attenzione clinica a causa dei sintomi da esse provocati. Lo studio, effettuato su una corte di 19 pazienti stratificati nel decennio 2002-2012, ricoverati presso l’Unità Operativa di Neurochirurgia dell’Azienda Ospedaliera Pisana, ha messo in risalto una serie di dati clinico-epidemiologici, tra cui l’età media dei soggetti, il sesso, il quadro sintomatologico presentato, le caratteristiche anatomo-patologiche delle ernie, le indagini diagnostiche effettuate. Particolare attenzione è stata posta in merito a due punti: -la latenza in mesi che è intercorsa tra sviluppo dei primi sintomi e diagnosi; -i giorni di degenza media e le complicanze post-chirurgiche in relazione all’intervento praticato. Lo studio del primo punto ha voluto mettere in luce come una patologia con un’incidenza piuttosto bassa, e spesso caratterizzata da manifestazioni cliniche “atipiche”, rispetto a quelle classiche delle più comuni ernie lombari o cervicali, possa “sfuggire” alla diagnosi, con tempi che, nella casistica esaminata, sono andati da 0 a 36 mesi. Tutto ciò comporta ritardi nella diagnosi, ritardi terapeutici e possibile aggravamento progressivo dei sintomi. Lo studio del secondo punto, invece, ha focalizzato l’attenzione su tre tipi di approcci maggiormente praticati nell’AOUP. I risultati hanno messo in luce come alcuni approcci chirurgici possano essere gravati da un maggior tasso di complicanze e possano essere correlati a tempi di degenza media superiori rispetto ad altri. Tuttavia, pur riconoscendo per alcune tecniche un’invasività maggiore, alcune caratteristiche dell’ernia discale dorsale, tra cui la centralità, la calcificazione, l’eventuale invasione durale, giustificano e rendono necessari alcuni tipi di approccio chirurgico per la completa escissione del disco erniato, la decompressione del midollo spinale e la remissione del quadro neurologico del paziente

Diagnostics of the tropical tropopause layer from in-situ observations and CCM data

A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on vertical tracer profiles and relative vertical tracer gradients, using tropopause-referenced coordinates, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS). Observations were obtained during four tropical campaigns performed from 1999 to 2006 with the research aircraft Geophysica and have been compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL (~500 m) allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone and carbon monoxide gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified by their different chemical composition. The joint analysis and comparison of observed and modelled data allows to state that the model can represent the background TTL structure and its seasonal variability rather accurately. The model estimate of the thickness of the interface region between tropospheric and stratospheric regimes agrees well with average values inferred from observations. On the other hand, the measurements can be influenced by regional scale variability, local transport processes as well as deep convection, that can not be captured by the model

Diagnostics of the tropical tropopause layer from in-situ observations and CCM data

A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on the vertical tracers profiles, relative vertical tracers gradients, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS), using tropopause coordinates. Observations come from the four tropical campaigns performed from 1998 to 2006 with the research aircraft Geophysica and have been directly compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified, first, by their differing chemical composition. The joint analysis and comparison of observed and modelled data allows us to evaluate the capability of the model in reproducing the observed vertical structure of the TTL and its variability, and also to assess whether observations from particular regions on a monthly timescale can be representative of the fine scale mean structure of the Tropical Tropopause Layer

Impact of deep convection in the tropical tropopause layer in West Africa: in-situ observations and mesoscale modelling

We present the analysis of the impact of convection on the composition of the tropical tropopause layer region (TTL) in West-Africa during the AMMA-SCOUT campaign. Geophysica M55 aircraft observations of water vapor, ozone, aerosol and CO2 show perturbed values at altitudes ranging from 14 km to 17 km (above the main convective outflow) and satellite data indicates that air detrainment is likely originated from convective cloud east of the flight. Simulations of the BOLAM mesoscale model, nudged with infrared radiance temperatures, are used to estimate the convective impact in the upper troposphere and to assess the fraction of air processed by convection. The analysis shows that BOLAM correctly reproduces the location and the vertical structure of convective outflow. Model-aided analysis indicates that in the outflow of a large convective system, deep convection can largely modify chemical composition and aerosol distribution up to the tropical tropopause. Model analysis also shows that, on average, deep convection occurring in the entire Sahelian transect (up to 2000 km E of the measurement area) has a non negligible role in determining TTL composition

A new head-mounted display-based augmented reality system in neurosurgical oncology: a study on phantom

Purpose: Benefits of minimally invasive neurosurgery mandate the development of ergonomic paradigms for neuronavigation. Augmented Reality (AR) systems can overcome the shortcomings of commercial neuronavigators. The aim of this work is to apply a novel AR system, based on a head-mounted stereoscopic video see-through display, as an aid in complex neurological lesion targeting. Effectiveness was investigated on a newly designed patient-specific head mannequin featuring an anatomically realistic brain phantom with embedded synthetically created tumors and eloquent areas. Materials and methods: A two-phase evaluation process was adopted in a simulated small tumor resection adjacent to Brocaâ\u80\u99s area. Phase I involved nine subjects without neurosurgical training in performing spatial judgment tasks. In Phase II, three surgeons were involved in assessing the effectiveness of the AR-neuronavigator in performing brain tumor targeting on a patient-specific head phantom. Results: Phase I revealed the ability of the AR scene to evoke depth perception under different visualization modalities. Phase II confirmed the potentialities of the AR-neuronavigator in aiding the determination of the optimal surgical access to the surgical target. Conclusions: The AR-neuronavigator is intuitive, easy-to-use, and provides three-dimensional augmented information in a perceptually-correct way. The system proved to be effective in guiding skin incision, craniotomy, and lesion targeting. The preliminary results encourage a structured study to prove clinical effectiveness. Moreover, our testing platform might be used to facilitate training in brain tumour resection procedures

Comparison of Antarctic polar stratospheric cloud observations by ground-based and space-borne lidar and relevance for chemistry–climate models

Abstract. A comparison of polar stratospheric cloud (PSC) occurrence from 2006 to 2010 is presented, as observed from the ground-based lidar station at McMurdo (Antarctica) and by the satellite-borne CALIOP lidar (Cloud-Aerosol Lidar with Orthogonal Polarization) measuring over McMurdo. McMurdo (Antarctica) is one of the primary lidar stations for aerosol measurements of the NDACC (Network for Detection of Atmospheric Climate Change). The ground-based observations have been classified with an algorithm derived from the recent v2 detection and classification scheme, used to classify PSCs observed by CALIOP. A statistical approach has been used to compare ground-based and satellite-based observations, since point-to-point comparison is often troublesome due to the intrinsic differences in the observation geometries and the imperfect overlap of the observed areas. A comparison of space-borne lidar observations and a selection of simulations obtained from chemistry–climate models (CCMs) has been made by using a series of quantitative diagnostics based on the statistical occurrence of different PSC types. The distribution of PSCs over Antarctica, calculated by several CCMVal-2 and CCMI chemistry–climate models has been compared with the PSC coverage observed by the satellite-borne CALIOP lidar. The use of several diagnostic tools, including the temperature dependence of the PSC occurrences, evidences the merits and flaws of the different models. The diagnostic methods have been defined to overcome (at least partially) the possible differences due to the resolution of the models and to identify differences due to microphysics (e.g., the dependence of PSC occurrence on T−TNAT). A significant temperature bias of most models has been observed, as well as a limited ability to reproduce the longitudinal variations in PSC occurrences observed by CALIOP. In particular, a strong temperature bias has been observed in CCMVal-2 models with a strong impact on PSC formation. The WACCM-CCMI (Whole Atmosphere Community Climate Model – Chemistry-Climate Model Initiative) model compares rather well with the CALIOP observations, although a temperature bias is still present

Teleconnections of the Quasi‐Biennial Oscillation in a multi‐model ensemble of QBO‐resolving models

The Quasi-biennial Oscillation (QBO) dominates the interannual variability of the tropical stratosphere and influences other regions of the atmosphere. The high predictability of the QBO implies that its teleconnections could lead to increased skill of seasonal and decadal forecasts provided the relevant mechanisms are accurately represented in models. Here modelling and sampling uncertainties of QBO teleconnections are examined using a multi-model ensemble of QBO-resolving atmospheric general circulation models that have carried out a set of coordinated experiments as part of the Stratosphere-troposphere Processes And their Role in Climate (SPARC) QBO initiative (QBOi). During Northern Hemisphere winter, the stratospheric polar vortex in most of these models strengthens when the QBO near 50 hPa is westerly and weakens when it is easterly, consistent with, but weaker than, the observed response. These weak responses are likely due to model errors, such as systematically weak QBO amplitudes near 50 hPa, affecting the teleconnection. The teleconnection to the North Atlantic Oscillation is less well captured overall, but of similar strength to the observed signal in the few models that do show it. The models do not show clear evidence of a QBO teleconnection to the Northern Hemisphere Pacific-sector subtropical jet

Survival outcomes in patients with recurrent glioblastoma treated with Laser Interstitial Thermal Therapy (LITT): A systematic review

To study the role of laser interstitial thermal therapy in recurrent glioblastoma and to assess its effect in the overall survival and in progression-free survival

Subdural fluid collection and hydrocephalus following cervical schwannoma resection: hydrocephalus resolution after spinal pseudomeningocele repair: case report

The authors report the case of a 31-year-old man who developed neck pain and headache 2 months after the uncomplicated resection of a cervical schwannoma. MR imaging revealed infratentorial subdural fluid collections and obstructive hydrocephalus associated with cervical pseudomeningocele. The clinical symptoms, subdural fluid collections, and ventricular dilation resolved after surgical correction of the pseudomeningocele. This report emphasizes that hydrocephalus may be related to disorders of cerebrospinal fluid flow dynamics induced by cervical pseudomeningocele. In these rare cases, both the hydrocephalus and the symptoms are resolved by the simple correction of the pseudomeningocele