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BackgroundFor the surgical treatment of early-stage laryngeal cancer, the use of transoral laser microsurgery (TLM) has emerged as the gold standard. However, this procedure requires a straight line of sight to the operating field. Therefore, the patient's neck needs to be brought into a hyperextended position. In a considerable number of patients, this is not possible due to anomalies in the cervical spine anatomy or soft tissue scarring, e.g., after radiation. In these cases, adequate visualization of relevant laryngeal structures cannot be ensured using a conventional rigid operating laryngoscope, which may negatively affect the outcome of these patients.MethodsWe present a system based on a 3D-printed prototype of a curved laryngoscope with three integrated working channels (sMAC). The curved profile of the sMAC-laryngoscope is specifically adapted to the nonlinear anatomy of the upper airway structures. The central working channel provides access for flexible video endoscope imaging of the operating field while the two remaining channels provide access for flexible instrumentation. In a user study (n = 11), visualization and reachability of relevant laryngeal landmarks as well as the feasibility of basic surgical procedures with the proposed system were examined in a patient simulator. In a second setup, the system was evaluated for its applicability in a human body donor.ResultsAll participants of the user study were able to visualize, reach and manipulate the relevant laryngeal landmarks. Reaching those took significantly less time in the second attempt compared to the first one (27.5 s ± 5.2 s vs. 39.7 s ± 16.5 s, p = 0.008) indicating a significant learning curve for handling the system. Instrument changes were performed quickly and reliably by all participants (10.9 s ± 1.7 s). All participants were able to bring the bimanual instruments into position for a vocal fold incision. Relevant laryngeal landmarks could be visualized and reached in the human body donor setup.ConclusionPossibly, the proposed system may develop into an alternative treatment option for patients with early-stage laryngeal cancer and restricted mobility of the cervical spine in the future. Further improvements of the system could include finer end effectors and a flexible instrument with a laser cutting tool.

Land surface models calculate runoff from the land surface. Therefore they must be coupled to a hydrological model to receive the streamflow which then allows for the comparison to measurements at gauging stations. The land surface model TERRA-ML of the weather forecast model COSMO of the German Weather Service is coupled to a river routing model and applied to the Enz watershed upstream of Höfen (Baden-Württemberg, Germany). The comparison of simulated to measured streamflow revealed, deficiencies in the hydraulic conductivity parameterization and in the applied soil texture data set. Small changes in the vertical soil water fluxes and high resolution soil texture data led to a significant improvement in the streamflow simulation. This resulted in different simulations of evapotranspiration and soil moisture, namely in spring and early summer, i.e. during the most pronounced growing season.

We evaluate the runoff-simulation performance of a water transport model (routing scheme) coupled to the Land Surface Parameterization module TERRA-ML of the operational COSMO (Consortium for Small-Scale Modelling) weather forecast model. In addition to the successful implemention of the routing scheme, we also included an alternative vertical soil water transport parameterisation in TERRA-ML in order to estimate the uncertainty caused by the component of the LSP central to runoff generation. A combination of two data sets, both operational products by DWD, is used for precipitation input. These are the hourly precipitation data set RADOLAN RW, which is based on radar data and is calibrated by rain gauges, as well as the daily REGNIE data set, which is only based on gauge data. The mesoscale Sieg river catchment located in Western Germany is used as the evaluation testbed. The extended TERRA-ML was run in standalone mode (decoupled from the atmospheric part of the COSMO model) with 1 × 1 km spatial resolution from April to September 2005 based on and provided with spatially more detailed descriptions of topography, land use and soil texture. The model was driven by operational COSMO analysis data and two different sources of observed precipitation (gauge and radar measurements). The results are compared to discharge measurements. They indicate a good representation of the observed discharge by the extended TERRA-ML system. The additionally implemented linear vertical soil water parameterization overestimates total discharge less (6 %) than the default exponential parameterization (20 %) when compared to a gauging station located at the lower reaches of the river Sieg. Suggestions are given on how to further enhance the modelled discharge by improvements in the LSP scheme.