Impact of Ureteral Stent Material on Stent-related Symptoms: A Systematic Review of the Literature

CONTEXT Ureteral stents are essential implants that are used on a daily basis. Since their invention, advances in stent design have been directed towards alleviating stent-related symptoms. It remains unclear how the material composition of the stent affects stent-related symptoms. OBJECTIVE To review the literature and define the clinical impact of ureteral stent material on stent-related symptoms. EVIDENCE ACQUISITION A literature search of the Embase, MEDLINE (PubMed), and Web of Science databases was conducted on December 17, 2021 to collect articles comparing stent composition materials regarding stent-related symptoms. Thirteen publications met the inclusion criteria, of which only one met the high-quality requirements of the Cochrane Collaboration tool for assessing the risk of bias in randomized trials. EVIDENCE SYNTHESIS Most trials, including the highest quality trial, seem to support that silicone double-J (DJ) stents reduce stent-related symptoms compared to nonsilicone DJ stents. Regarding physical properties, it seems that "soft" or "flexible" DJ stents reduce stent-related symptoms. However, since there was only one high-quality study with a low risk of bias, it is impossible to draw a definitive conclusion owing to the lack of quality data. CONCLUSIONS Silicone DJ stents, and by extension "soft" DJ stents, appear to reduce stent-related symptoms compared to nonsilicone polymers and "hard" DJ stents. No definitive conclusion can be drawn owing to a lack of quality evidence. Creating a standard for measuring and reporting physical stent properties should be the first step for further research. PATIENT SUMMARY A ureteral stent is a small hollow tube placed inside the ureter to help urine drain from the kidney. We reviewed the literature on the impact of stent material on stent-related symptoms. We found that silicone may reduce stent-related symptoms, but no definitive conclusion can be drawn and further studies are needed

Prediction of exterior wind noise generated by a side-mirror of an SUV

Simulation methods predicting the aerodynamic and aeroacoustic performances of car components at an early stage of their design cycle are of the high importance. This paper focuses on the validation of an acoustic simulation technique for side-mirror noise for observers located outside of the car compartment, typical to component testing in anechoic wind tunnels. A hybrid simulation approach is accounted, where flow and acoustic-fields are separated. The flow field is computed a priori with an incompressible flow solver. The acoustic-field is then computed based on the information extracted from the CFD solver. A surface dipole based acoustic simulation technique is employed where the unsteady aerodynamic pressure loading on the side-mirror surface is treated as acoustic source field. The effect of the volumetric sources is then accounted in the surface source definition without exporting them from the CFD solver. The paper provides the acoustic simulations for two configurations on side mirror. The results are compared to data obtained in wind-tunnel measurement on the SUV