Search Results (1,812)

In this research, as-built Ti–6Al–4V anatomical plates were successfully fabricated using laser powder bed fusion (LPBF). This study thoroughly examines the microstructural evolution and its role in enhancing the mechanical properties of clavicle bone plates under sub-β-transus heat treatment for medical application. Scanning electron microscope (SEM) images of the as-built specimens reveal a dense formation of a hard α’ hcp martensite structure, which decomposes during annealing at 650 °C and ultimately transforms into an α + β lamellar structure at 950 °C. Additionally, coarse grains resulting from recrystallization and reduced dislocation density were observed through electron backscatter diffraction (EBSD) following heat treatment. Due to these microstructural evolutions, the desired mechanical properties of as-built Ti64 parts for surgical applications were achieved. Heat treatment of the anatomical plates at 950 °C demonstrated an excellent strength–ductility synergy under tensile deformation and the highest energy absorption capability under bending deformation, indicating sufficient durability for medical implantation applications. Full article

Zirconia is increasingly favored for dental implants owing to its corrosion resistance, hypoallergenic properties, and superior esthetics, but its biocompatibility remains a challenge. This study explores laser-assisted surface modification to enhance zirconia bioactivity. Zirconia transitions from the monoclinic to the tetragonal phase during sintering, with mixed phases observed in the pre-sintered stage. These transitions are critical for understanding its structural stability and malleability. Grid patterns were imprinted on the green body implant surface using a 1064 nm Nd-YAG laser (Continuum Surelite II, San Jose, CA, USA), with mesh sizes ranging from 7 to 50 µm and depths up to 2 µm, controlled by varying laser fluence, irradiation time, and templates. SEM, AFM, and XRD analyses were used to characterize the surface morphology and crystallography. Protein adsorption studies compared two patterned samples with different surface coverage—the first sample had a patterned area of 0.212 cm² (27%), while the second sample had a patterned area of 0.283 cm² (36%)—to a control sample. Protein adsorption increased by 92% in the first and 169% in the second sample, demonstrating a direct correlation between increased pattern area and bioactivity. Enhanced protein adsorption facilitates cell attachment and growth, which are crucial for improving osseointegration. These results underscore the potential of laser-assisted surface modification to optimize zirconia’s performance as a medical implant material. Full article

Acute cardiovascular disorders are incriminated in up to 33% of maternal deaths, and the presence of sickle cell anemia (SCA) aggravates the risk of peripartum complications. Herein, we present a 24-year-old Caribbean woman with known SCA who developed a vaso-occlusive crisis at 36 weeks of gestation that required emergency Cesarean section. In the early postpartum period, she experienced fever with rapid onset of acute respiratory distress in the context of COVID-19 infection that required tracheal intubation and mechanical ventilatory support with broad-spectrum antibiotics and blood exchange transfusion. Shortly thereafter, transthoracic echocardiography documented severe biventricular dysfunction associated with raising levels of cardiac troponin and ECG signs of myocardial ischemia. Medical treatment with incremental dobutamine and noradrenaline infusion failed to improve cardiac output and blood gas exchange. After consultation with the regional cardiac center, a prompt decision was made to provide cardiac and respiratory support via implantation of femoral cannula and initiation of veno-arterial extracorporeal membrane oxygenation (ECMO, Cardiohelp^®). Under stable ECMO, the patient was transferred by helicopter to a specialized cardiac center. There were no signs of ongoing hemolysis, and progressive recovery of the right and left ventricular function facilitated forward blood flow through the aortic valve. Three days after implantation, ECMO was weaned, and the cannula were removed. One day later, the patient’s chest X-rays showed partial resolution of lung edema. The patient was successfully extubated, and non-invasive ventilation with pulmonary rehabilitation was initiated to speed up her functional recovery. Full article

Autonomous electronic systems are becoming increasingly important in people’s lives, as a result of advances in efficient energy storage systems, devices that can be permanently implanted in humans, and the trend towards compact devices that function as an extension of the human body. In addition, strategies continue to be found for the integration of energy harvesting in a constant and efficient manner. Covering the numerous advances made in biomedical devices can be quite overwhelming. This work presents a review of the latest strategies developed to produce energy from human body activity, the energy collectors for devices, and the strategies to create ultra-low-power wearable devices. The review focuses on the potential energy sufficiency required to power devices that can be implanted or worn, while also providing information about the patient’s condition. A comparison between the energies produced by different instruments and the improvements in the development of low-consumption devices is presented, with a focus on the type of medical devices. A new approach is established to classify and locate the most recent advances in autonomous systems in biomedicine based on their complexity/function. Full article

Background: Mediastinal mass syndrome represents a major threat to respiratory and cardiovascular integrity, with difficult evidence-based risk stratification for interdisciplinary management. Methods: We conducted a narrative review concerning risk stratification and difficult airway management of patients presenting with a large mediastinal mass. This is supplemented by a case report illustrating our individual approach for a patient presenting with a subtotal tracheal stenosis due to a large cyst of the thyroid gland. Results: We identified numerous risk stratification grading systems and only a few case reports of regional anesthesia techniques for extracorporeal membrane oxygenation patients. Clinical Case: After consultation with his general physician because of exertional dyspnea and stridor, a 78-year-old patient with no history of heart failure was advised to present to a cardiology department under the suspicion of decompensated heart failure. Computed tomography imaging showed a large mediastinal mass that most likely originated from the left thyroid lobe, with subtotal obstruction of the trachea. Prior medical history included the implantation of a dual-chamber pacemaker because of a complete heart block in 2022, non-insulin-dependent diabetes mellitus type II, preterminal chronic renal failure with normal diuresis, arterial hypertension, and low-grade aortic insufficiency. After referral to our hospital, an interdisciplinary consultation including experienced cardiac anesthesiologists, thoracic surgeons, general surgeons, and cardiac surgeons decided on completing the resection via median sternotomy after awake cannulation for veno-venous extracorporeal membrane oxygenation via the right internal jugular and the femoral vein under regional anesthesia. An intermediate cervical plexus block and a suprainguinal fascia iliaca compartment block were performed, followed by anesthesia induction with bronchoscopy-guided placement of the endotracheal tube over the stenosed part of the trachea. The resection was performed with minimal blood loss. After the resection, an exit blockade of the dual chamber pacemaker prompted emergency surgical revision. The veno-venous extracorporeal membrane oxygenation was explanted after the operation in the operating room. The postoperative course was uneventful, and the patient was released home in stable condition. Conclusions: Awake veno-venous extracorporeal membrane oxygenation placed under local anesthetic infiltration with regional anesthesia techniques is a feasible individualized approach for patients with high risk of airway collapse, especially if the mediastinal mass critically alters tracheal anatomy. Compressible cysts may represent a subgroup with easy passage of an endotracheal tube. Interdisciplinary collaboration during the planning stage is essential for maximum patient safety. Prospective data regarding risk stratification for veno-venous extracorporeal membrane oxygenation cannulation and effectiveness of regional anesthesia is needed. Full article

Oral implantology faces a multitude of technical challenges in light of current clinical experience, underlining the need for innovation in implantable medical devices in both mechanical and biological terms. Objectives: This study explores the influence of the thickness factor of calcium-doped zirconia (Ca-SZ) coatings deposited by PVD on their intrinsic mechanical properties and the determinism of the latter on adhesion to the TA6V alloy substrate after mechanical loading for applications in dental implantology. Methods: Three separate thicknesses of 250 nm, 450 nm and 850 nm were evaluated in terms of mechanical strength, modulus of elasticity and adhesion to the substrate, in accordance with ISO 20502:2005. Results: The results show an increase in apparent modulus of elasticity with thickness, reaching values of around 25.05 GPa and 36.3 GPa, close to the cortical bone for the 250 nm and 450 nm thick coatings, respectively. Adhesion tests show a progressive improvement up to 450 nm, followed by a similar observation at 850 nm, underlining the importance of optimal thickness to balance mechanical protection and biomechanical compatibility. Furthermore, the initial roughness and topography of the substrate were not influenced by the different thicknesses of the Ca-SZ coating. Conclusions: Together, these results reinforce the potential of Ca-SZ coatings to minimise stress shielding in dental implants. Full article

Background and Clinical Significance: Cardiomyopathy is a significant cause of mortality in patients with Duchenne muscular dystrophy (DMD). Key prognostic factors include the age of onset of cardiomyopathy, low body mass index (BMI), and poor respiratory function. Detection of cardiac abnormalities can be challenging, which complicates timely diagnosis and treatment. Common treatments for heart failure include ACE inhibitors, beta-blockers, and mineralocorticoids. However, their effectiveness can vary, and the progression of cardiomyopathy may differ from one patient to another. Ongoing research aims to identify better therapeutic strategies and biomarkers for early intervention, ultimately improving the quality of life for patients affected by cardiomyopathy. New medications for heart failure, such as sodium/glucose co-transporter 2 inhibitors (SGLT2i) and valsartan/sacubitril (V/S), have been proposed, but their safety and efficacy in DMD patients remain unknown. Case Presentation: We present two cases that illustrate the histories of two patients who experienced different outcomes. The management of the first patient was complicated by several factors, including an early onset of cardiomyopathy, intolerance to ACE inhibitors, and untreated scoliosis, which hindered the implantation of a cardioverter defibrillator (ICD). Unfortunately, he only benefited from dapagliflozin in the later stages of his cardiomyopathy. Neurological complications further exacerbated the advanced state of his disease. In contrast, the second patient adhered to all recommended therapies, including innovative medications, and he currently has compensated heart failure. Conclusions: We concluded that several factors, beyond genetic ones, may have influenced their prognosis, including updated guidelines for cardiomyopathy treatment and the utilization of innovative medications. Full article

Introduction: To report the role of prostaglandin-associated periorbitopathy (PAP) severity on the surgical efficacy of Ahmed Glaucoma Valve (AGV) implantation. Subjects and Methods: Retrospective observational case series. Participants were the consecutive 102 eyes from 102 Japanese subjects (55 males, 47 females; mean age ± standard deviation, 74.9 ± 7.8 years) who underwent AGV implantation for primary open-angle glaucoma (POAG), completed full postoperative visits for 12 months, and had information on PAP severity graded by the Shimane University PAP Grading System (SU-PAP). Data were collected via medical chart review. Comparison of surgical success rates among groups stratified by SU-PAP grades (grades 0–3) using survival curve analysis. Failure was defined based on additional glaucoma surgery, IOP reduction in less than 20%, postoperative IOP exceeding 18 mmHg (definition A) or 15 mmHg (definition B), or postoperative visual acuity reduced to no light perception. Results: At 12 months postoperatively, the success rates for grades 0, 1, 2, and 3 were 47%, 43%, 42%, and 73%, respectively, for definition A (p = 0.35) and 35%, 26%, 19%, and 27%, respectively, for definition B (p = 0.64, log-rank test). For definition A, younger age was associated with surgical failure (Hazard ratio = 0.97/year, p = 0.049, Wald test), while no other factors, including gender, preoperative IOP, medications, refractive error, history of conjunctival manipulation procedures, or SU-PAP grade, were associated with surgical failure. For definition B, no factors were found to influence surgical outcomes. Conclusions: The preoperative severity of PAP might not affect the postoperative outcomes of AGV. Given that the success rate of trabeculectomy is influenced by PAP severity, in cases with severe PAP, physicians are advised to consider long-tube shunt surgery as an initial filtration procedure or as a rescue procedure when filtration surgery is unsuccessful. Full article

This review explores the advancements in additive manufacturing (AM) of biodegradable iron (Fe) and zinc (Zn) alloys, focusing on their potential for medical implants, particularly in vascular and bone applications. Fe alloys are noted for their superior mechanical properties and biocompatibility but exhibit a slow corrosion rate, limiting their biodegradability. Strategies such as alloying with manganese (Mn) and optimizing microstructure via laser powder bed fusion (LPBF) have been employed to increase Fe’s corrosion rate and mechanical performance. Zn alloys, characterized by moderate biodegradation rates and biocompatible corrosion products, address the limitations of Fe, though their mechanical properties require improvement through alloying and microstructural refinement. LPBF has enabled the fabrication of dense and porous structures for both materials, with energy density optimization playing a critical role in achieving defect-free parts. Fe alloys exhibit higher strength and hardness, while Zn alloys offer better corrosion control and biocompatibility. In vitro and in vivo studies demonstrate promising outcomes for both materials, with Fe alloys excelling in load-bearing applications and Zn alloys in controlled degradation and vascular applications. Despite these advancements, challenges such as localized corrosion, cytotoxicity, and long-term performance require further investigation to fully harness the potential of AM-fabricated Fe and Zn biodegradable implants. Full article

This article presents an evaluation of the accelerated aging impact on the structural properties of biodegradable PLA/HAp implants produced using 3D printing technology for use in traumatic bone defect repairs in individual patients. The designed biodegradable implants were sterilized with a radiation dose of 25 ± 0.99% kGy, then exposed to an accelerated aging process. Selected physicomechanical and chemical properties of biodegradable implants were evaluated with FT-IR spectra analyses and DSC. The accelerated aging process, carried out according to the ASTM F 1980:2002 “Standard Guide for Accelerated Aging of Sterile Barrier Systems and Medical Devices”, simulates three years of implant usage. It confirmed the stability of structural, physical and mechanical properties and proved the effectiveness and safety of the implants’ application. The present study was conducted to determine the shelf-life of newly developed biodegradable implants proposed for the treatment of children and adolescents where bone growth still occurs by using accelerated aging methodologies, allowing the assessment of changes in performance that do not result in a negative impact on the safety of the medical device. Full article

Ti and Ti6Al4V alloy are extensively utilized in structural parts in engineering applications and the production of medical implants due to their excellent mechanical properties, lightweight, and high corrosion resistance. This study comprehensively evaluates their corrosion behavior in three challenging aquatic environments: brackish water, seawater, and seawater bittern. Utilizing open circuit potential (E_OC) measurements with polarization techniques (linear and potentiodynamic) and electrochemical impedance spectroscopy (EIS) measurements, the research highlights distinct environmental influences on corrosion performance. Notably, Ti and Ti6Al4V alloy demonstrated exceptional stability with the highest polarization resistance and lowest corrosion current in brackish water, while seawater bittern presented the most demanding condition for Ti6Al4V. Additionally, the analysis of the electrode surfaces after polarization measurements using optical microscopy, optical profilometry, and SEM/EDS tests revealed minor damage, indicating the high corrosion resistance of these materials. This study advances the understanding of Ti and Ti6Al4V alloy performance in diverse environments and offers valuable insights for optimizing their use in harsh aquatic conditions, particularly for applications requiring durability and longevity. Full article

Biomaterials have assumed a decisive role in modern medicine by enabling significant advancements in medical care practices. These materials are designed to interact with biological systems, offering substantial solutions for various medical needs. In this research, bioceramic materials consisting of a bioactive hydroxyapatite-based matrix with Ti nanoparticles were processed as promising materials. These bioceramics were obtained using mechanical milling, uniaxial pressing, and sintering as powder processing techniques. This study evaluates the effect of Ti additions on the structural, electrochemical, and mechanical properties of the hydroxyapatite ceramic material. Titanium additions were about 1, 2 and 3 wt%. The experimental results demonstrate that the biocomposite’s structure has two hexagonal phases: one corresponding to the hydroxyapatite matrix and the other to the Ti as a reinforced phase. The biomaterials’ microstructure is completely fine and homogeneous. The biomaterial reinforced with 1 wt. % Ti exhibits the best mechanical behavior. In this context, electrochemical tests reveal that bioceramics can achieve stability through an ion adsorption mechanism when exposed to a physiological electrolyte. Bioceramics, particularly those containing 1%Ti, develop their bioactivity through the formation of a high-density hydroxide film during a porous sealing process at potentials around −782.71 mV, with an ionic charge transfer of 0.43 × 10⁻⁹ A/cm². Finally, this biofilm behaves as a capacitor Cc = 0.18 nF/cm², resulting in lower ionic charge transfer resistance (Rct = 1.526 × 106 Ω-cm²) at the interface. This mechanism promotes the material’s biocompatibility for bone integration as an implant material. Full article

Background/objectives: Vancomycin is commonly used in the treatment of periprosthetic joint infection (PJI), and trough concentrations are measured to ascertain that they are within the therapeutic range. It has not been investigated what proportion of vancomycin concentrations during treatment of PJI patients is accurately within this range, how many dose adjustments are commonly needed, and which patient factors predispose towards aberrations from the desired range. Method: In this single-center cohort study, we investigated vancomycin trough concentrations in 108 patients with surgically treated PJI who received IV administered vancomycin treatment post-operatively. Patients were identified in our local arthroplasty register, and data beyond what was available in the register were collected from electronic medical charts. Results: Of the final study cohort, 41% were women, and the median age was 71 (IQR 63–79) years. Most patients had PJI of the hip (73%), the majority (54%) underwent a debridement, antibiotics and implant retention (DAIR) procedure prior to vancomycin treatment, and 39% received vancomycin-loaded bone cement during the preceding revision procedure. Of 791 vancomycin trough measurements, only 58.2% were within the target range of 15–20 mg/L, 18.5% were below, and 23.4% were above. A total of 71% of all patients required at least one dose adjustment, and the median length of vancomycin treatment was 8 days. We observed positive correlations of vancomycin trough concentrations with both age (Spearman’s rho = 0.35, p < 0.001) and pre-treatment creatinine concentrations (Spearman’s rho = 0.34, p < 0.001), but no statistically significant difference between patients who had received vancomycin-loaded bone cement and those who had not. Conclusions: In our PJI patients, a high proportion of vancomycin trough concentrations were outside the therapeutic range, despite adherence to local and national guidelines. We can also confirm that caution needs to be exerted in patients of advanced age and those with compromised kidney function. Alternative broad-spectrum antibiotics that do not require as extensive therapeutic drug monitoring should be further explored. Full article

Electrospun poly(ε-caprolactone) (PCL)-based scaffolds are widely used in tissue engineering. However, low cell adhesion remains the key drawback of PCL scaffolds. It is well known that nitrogen-doped diamond-like carbon (N-DLC) coatings deposited on the surface of various implants are able to enhance their biocompatibility and functional properties. Herein, we report the utilization of the pulsed vacuum arc deposition (PVAD) technique for the fabrication of thin N-DLC coatings on the surface of electrospun PCL scaffolds. The effect of N-DLC coating deposition under various nitrogen pressures on the morphological, mechanical, physico-chemical, and biological properties of PCL scaffolds was investigated. It was established that an increase in nitrogen pressure in the range from 5 × 10⁻³ to 5 × 10⁻¹ Pa results in up to a 10-fold increase in the nitrogen content and a 2-fold increase in the roughness of the PCL fiber surface. These factors provided the conditions for the enhanced adhesion and proliferation of human mesenchymal stem cells (MMSCs) on the surface of the modified PCL scaffolds. Importantly, the preservation of N-DLC coating properties determines the shelf life of a coated medical device. The elemental composition, tensile strength, and surface human MMSC adhesion were studied immediately after fabrication and after 6 months of storage under normal conditions. The enhanced MMSC adhesion was preserved after 6 months of storage of the modified PCL-based scaffolds under normal conditions. Full article

Background: This study compares the long-term intraocular pressure (IOP)-lowering efficacy of standalone MINIject (iSTAR Medical, Belgium) suprachoroidal implantation and two iStent (Glaukos, CA, USA) trabecular bypass implantation using a systematic review and meta-analysis. Methods: Systematic review of standalone implantation of MINIject or iStent inject with at least 24 months of follow up. The mean and standard deviation of IOP and the number of IOP-lowering medications at baseline and at 24 months were extracted. Weighted estimates of the outcome variables were calculated using random-effects meta-analysis models. Heterogeneity in the outcome measures among the studies was quantified using I². Results: Seven studies (three studies for MINIject and four for iStent) comprising 280 eyes were included. At 24 months, there was a greater reduction in IOP from baseline in the MINIject vs. two iStent cohorts (−9.57 vs. −4.92 mmHg, p = 0.03). The change from baseline in mean medication use was −1.00 with MINIject and −0.56 medications with iStent (p = 0.26). The mean percentage IOP reduction at 24 months ranged from 36.3−42.2% with MINIject compared to 5.2−40.7% with iStent, with greater variability in mean change from baseline in IOP observed in the iStent group (I² = 96.5% vs. 0%). The most frequent adverse events for MINIject were anterior chamber inflammation, best-corrected visual acuity (BCVA) loss, hyphema, and conjunctival hemorrhage, and for iStent, these were device obstruction, BCVA loss, IOP spike, and cataract progression. Conclusions: While both MINIject and iStent inject devices resulted in significant reductions in IOP and IOP medication use, standalone MINIject may provide a greater and more consistent reduction in IOP. Full article