Objectives The objective of this study was to evaluate the sealing ability of the implant-abutment interface in a specific implant system in comparison to other implant systems under conditions of increasing dynamic loading. Methods Three different implants and four abutment types were tested: one implant with a conical abutment connection, one implant with a flat abutment connection, and one implant with an abutment switch feature and two different abutment connections. The tests consisted of a phase of cyclic loading followed by a leakage test. The maximum loading force was increased, and the procedure was repeated, until either the implant-abutment connection failed, or a leakage was detected. Loading criteria were modified based on the ISO standard 14801:2016. Results The conical implant abutment connections exhibited fracture prior to leakage at varying failure forces and loading cycles, whereas the platform abutment type showed leakage or fracture at a relatively low force. The two different abutment types used on the same implant system showed extremely different results. Conclusions Literature shows similar high chewing forces mostly only for healthy subjects. For patients with dental implants, leakage is still preferable to fracture. In conclusion, the test showed that some implants with a conical abutment are more resistant to leakage and may be preferable if higher chewing forces are expected.
Objectives This study aimed to enhance the comprehension of volumetric bone mineral density (vBMD) changes following Total Hip Arthroplasty (THA) by establishing a protocol to (i) precisely locate alterations in the proximal femur in three dimensions and (ii) evaluate these changes over an extended period. Methods Twelve individuals who underwent unilateral THA, using either cemented or uncemented prostheses, were recruited. CT-scans of the proximal femur were acquired at three distinct time points: 24 h, 1 and 6 years post-surgery. Utilizing the acquired data, 3D models of the proximal femur were generated, and a novel algorithm was developed to categorize them into Gruen zones. Comparative analysis of density values among the three sets of scans allowed the calculation of bone density gains/losses for the entire proximal femur and specific regions. Results A lower trabecular bone quantity was observed in the cemented group compared to the uncemented cohort, with discernible differences in vBMD evolution observed in the overall femur and certain Gruen zones. Noteworthy inter-patient variability was evident, ranging from physiological bone remodeling to unexpected increases/decreases in vBMD (e.g.,+340 % after one year). Conclusions This analysis proves to be a valuable tool to understand the long-term vBMD evolution in THA patients.
Objectives This study aimed to determine the impact of physiological loading and boundary conditions on the biomechanical performance of a plating system for femoral shaft osteosynthesis via axial implant system testing (IST). Specifically, the effects of rotational load boundary conditions and realistic gait-based load patterns were evaluated to understand their influence on the biomechanical response and failure modes of the implant system. Methods Two test configurations – Fix-Free, featuring a rotational joint, and Fix-Fix, with fixed support at both ends – were subjected to static and cyclic loading. Cyclic testing incorporated sinusoidal and gait-based load patterns, reflecting the physiological axial joint load during walking. In total, 30 test samples (n=30), employed by a bone surrogate and the plate-screw system in bridge-plating state, were tested via axial IST. Results The Fix-Free configuration exhibited significantly lower axial stiffness and load capacity reductions of 60.8 % compared to Fix-Fix in static testing. Under cyclic gait-based loading, both setups experienced progressive screw-plate interface failures, with earlier degradation observed in Fix-Free. Conclusions Findings indicate a strong impact of physiological load patterns and boundary conditions. The results support the need for standards and guidelines for biomechanical testing of osteosynthetic plating systems via IST with universal physiological boundaries.
Objectives Identification of bony landmarks in medical images is of high importance for 3D planning in orthopaedic surgery. Automated landmark identification has the potential to optimize clinical routines and allows for the scientific analysis of large databases. To the authors’ knowledge, no direct comparison of different methods for automated landmark detection on the same dataset has been published to date. Methods We compared 3 methods for automated femoral landmark identification: an artificial neural network, a statistical shape model and a geometric approach. All methods were compared against manual measurements of two raters on the task of identifying 6 femoral landmarks on CT data or derived surface models of 202 femora. Results The accuracy of the methods was in the range of the manual measurements and comparable to those reported in previous studies. The geometric approach showed a significantly higher average deviation compared to the manually selected reference landmarks, while there was no statistically significant difference for the neural network and the SSM. Conclusions All fully automated methods show potential for use, depending on the use case. Characteristics of the different methods, such as the input data required (raw CT/segmented bone surface models, amount of training data required) and/or the methods robustness, can be used for method selection in the individual application.
Objectives Contaminated apparatus and surgical tools pose serious health risks. For such purpose, disinfection chambers are employed. However, these systems rely on mercury-based UV lamps which comes with various drawbacks. These limitations have driven interest in Ultraviolet-C Light Emitting Diode (UV-C LED) technology as a safer and more efficient alternative. However, existing studies have not thoroughly explored the impact of varying intensities of pulse width modulation (PWM) on disinfection efficacy. Methods To addess this, the present study designed and tested a LED-based disinfection chamber by employing 4-W 275 nm Surface Mount Device (SMD) LEDs against frequently isolated bacteria. By following prior approach, irradiation time was alternated at 30-s intervals and antibacterial efficacy was assessed through various parameters. Additionally, scanning electron microscopy (SEM) was performed to examine the morphological changes. Results Results indicated that the reduction was significantly influenced (p<0.05) with varying PWM levels (60–100 %), achieving 2.05-log 10 and 1.54-log 10 inactivation against Escherichia coli and Staphylococcus aureus, respectively, upon exposure to 51.24 mJ/cm 2 under maximum exposure settings. Moreover, complete cellular damage leading to bleb protrusion and cell-leakage confirmed the disruption of bacterial DNA. Conclusions In conclusion, UV-LEDs show great potential for disinfection, with efficiency influenced by PWM and dosage.
Objectives The electrical bioimpedance (EBI) technique has been used to measure gastric motility and emptying parameters. A well-known technique for this purpose is electrogastrography (EGG). No correlation between EGG signal and mechanical motility has been reported. In this study, a direct data comparison of these two techniques was performed. Methods 23 volunteers underwent simultaneous gastric monitoring using EGG and EBI. Signal processing was performed to isolate the slow waves of 0.5–9 cpm. The parameters obtained from 70 % overlapped time slots of 3.5 min, included the dominant frequency and power of the normo-gastric region and the percentage of brady-, normo-, and tachy-gastric slow waves. Results The EGG showed slightly higher values in dominant frequencies, whereas EBI displayed higher variability. High-frequency features were more significant in the EBI, with lower variability, and correlations were found in approximately half of the frequency spectra. Slow waves exhibited poor correlation, but were significant at 95 % of the timeslots. Conclusions Comparing EBI and EGG, global parameters in the normogastric region had slight variances, which may not significantly impact clinical findings. The sensitivity of the EBI to higher frequencies is evident.
Objectives Pilots are susceptible to fatigue during flight operations, posing significant risks to flight safety. However, single-feature-based detection methods often lack accuracy and robustness. Methods This study proposes a fatigue classification approach that integrates EEG features and motion behavior features to enhance fatigue recognition and improve aviation safety. The method extracts energy ratios of EEG frequency bands ( α , β , θ , δ ), incorporates forearm sample entropy and Euler angle standard deviation, and applies Pearson correlation analysis to select key features. Finally, a Support Vector Machine (SVM) classifier is employed to achieve precise fatigue classification. Results Experimental findings indicate that the proposed method achieves a test accuracy of 93.67 %, outperforming existing fatigue detection techniques while operating with a reduced computational cost. Conclusions This study addresses a gap in current research by integrating physiological and behavioral data for fatigue classification, demonstrating that the fusion of multi-source information significantly enhances detection accuracy and stability compared to single-feature methods. The findings contribute to improved pilot performance and enhanced flight safety by increasing the reliability of fatigue monitoring systems.
Objectives This study evaluates how research output and impact in medical informatics vary among EU member states before and during the COVID-19 pandemic by analyzing publication volume, impact metrics, collaboration patterns, and open-access trends. It seeks to identify regional disparities, highlight key research themes, and provide insights for researchers, the public, and policymakers to promote equitable access, collaboration, and investment in medical informatics across the EU. Methods A bibliometric analysis was performed using Clarivate Web of Science and InCites databases, encompassing 6,620 articles from 47 medical informatics journals published between 2018 and 2022. Metrics such as cumulative impact factors, article counts, and collaboration trends were analyzed. Results Our analysis identified substantial regional disparities in research output and impact. Western European countries, including Germany, the Netherlands, and Spain, consistently led in article volume and cumulative impact factors, while Eastern European countries showed lower engagement. Collaboration metrics revealed that 66 % of publications involved international partnerships, showcasing strong cross-border cooperation within the EU. Conclusions This study highlights the uneven distribution of research productivity in medical informatics across the EU. The findings underline the importance of international partnerships and equitable access to research in advancing medical informatics and addressing evolving healthcare challenges.
