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Neuron Oct 2020This Perspective examines the status of large-scale cortical interfaces through the lens of potential applications to active implants for brain-machine interfaces.... (Review)
Review
This Perspective examines the status of large-scale cortical interfaces through the lens of potential applications to active implants for brain-machine interfaces. Examples of research and development in a still embryonic field are discussed from a neuroengineer's perspective, touching on the design of scalable electrophysiological sensors with the ambition to access thousands of cortical points at near-cellular-level resolution. Important issues include microscale geometry of neural probes, design of implantable ultra-low-power electronics, implementation of high-data-rate wireless telemetry, and compatible device packaging-all requiring advanced solutions along a translational path for chronic human use.
Topics: Animals; Brain-Computer Interfaces; Cerebral Cortex; Electric Stimulation; Electrodes, Implanted; Humans; Neurosciences; Prostheses and Implants; Telemetry
PubMed: 33120022
DOI: 10.1016/j.neuron.2020.10.015 -
Indian Journal of Ophthalmology Apr 2023Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined... (Review)
Review
Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined with adnexal complications secondary to chronic cicatrizing conjunctivitis is a highly complex situation to treat. In such eyes, procedures such as penetrating keratoplasty alone or combined with limbal stem cell transplantation are doomed to fail. In these eyes, keratoprosthesis (Kpro) or an artificial cornea is the most viable option, eliminating corneal blindness even in eyes with autoimmune disorders such as Stevens-Johnson syndrome, ocular mucous membrane pemphigoid, Sjogren's syndrome, and nonautoimmune disorders such as chemical/thermal ocular burns, all of which are complex pathologies. Performing a Kpro in these eyes also eliminates the need for systemic immunosuppression and may provide relatively early visual recovery. In such eyes, the donor cornea around the central cylinder of the Kpro needs to be covered with a second layer of protection to avoid desiccation and progressive stromal melt of the underlying cornea, which is a common complication in eyes with severe DED. In this review, we will focus on Kpro designs that have been developed to survive in eyes with the hostile environment of severe DED. Their outcomes in such eyes will be discussed.
Topics: Humans; Cornea; Prostheses and Implants; Corneal Diseases; Dry Eye Syndromes; Blindness; Retrospective Studies; Prosthesis Implantation
PubMed: 37026247
DOI: 10.4103/IJO.IJO_2817_22 -
Journal of the American College of... Oct 2019
Topics: Acute Coronary Syndrome; Coronary Artery Disease; Humans; Monitoring, Physiologic; Prostheses and Implants; Time-to-Treatment
PubMed: 31623763
DOI: 10.1016/j.jacc.2019.08.1011 -
International Journal of Environmental... Jun 2020We aimed to assess the biological and mechanical-technical complications and survival rate of implants of full-arch metal-ceramic prostheses, during five years of...
We aimed to assess the biological and mechanical-technical complications and survival rate of implants of full-arch metal-ceramic prostheses, during five years of follow-up. 558 implants (of three different brands) retaining 80 full-arch metal-ceramic prostheses were placed in 65 patients, all of whom were examined annually for biological and mechanical-technical complications during the five years of follow-up. Descriptive statistics and univariate logistic regression were calculated. The cumulative survival rate of the implants was 99.8%, and 98.8% prosthesis-based. Mucositis was the most frequent of the biological complications and peri-implantitis was recorded as 13.8% at restoration-level, 16.9% at patient level and 2.0% at implant level. An implant length greater than 10 mm was shown to be a protective factor against biological complications. The mechanical-technical complications were associated with implant diameter, abutment/implant connection and retention system. Loss of screw access filling was the most frequent prosthetic complication, followed by the fracture of the porcelain. Full-arch metal-ceramic prostheses show a high prevalence of implant and prosthesis survival, with few biological and mechanical-technical complications.
Topics: Aged; Aged, 80 and over; Artificial Limbs; Ceramics; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Female; Follow-Up Studies; Humans; Male; Metals; Middle Aged; Postoperative Complications; Retrospective Studies
PubMed: 32545913
DOI: 10.3390/ijerph17124250 -
Journal of the American College of... Apr 2020
Topics: Aortic Valve; Aortic Valve Stenosis; Humans; Prostheses and Implants; Prosthesis Failure; Transcatheter Aortic Valve Replacement
PubMed: 32327099
DOI: 10.1016/j.jacc.2020.03.017 -
Clinical Microbiology Reviews Apr 2022The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the... (Review)
Review
The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.
Topics: Bacteria; Biofilms; Humans; Prostheses and Implants
PubMed: 35044203
DOI: 10.1128/cmr.00221-20 -
Dental and Medical Problems 2022Delayed loading in the rehabilitation of edentulous patients with an implant-supported prosthesis implies a longer treatment time. It requires additional surgery to...
BACKGROUND
Delayed loading in the rehabilitation of edentulous patients with an implant-supported prosthesis implies a longer treatment time. It requires additional surgery to uncover the submerged implants, and this may increase patients' discomfort and morbidity.
OBJECTIVES
The immediate loading-based technique described in this article involves creating a metal framework by intraorally welding the implants pair by pair, using specific wing abutments. The aim of the study was to investigate the implant-prosthetic success and complication rates of this technique when used to rehabilitate totally edentulous patients.
MATERIAL AND METHODS
The clinical records of totally edentulous patients were retrospectively evaluated. The prosthetic success rate as well as technical and biological complications were analyzed. Furthermore, the implant survival and success rates were assessed by measuring marginal bone loss (MBL) at the implant, prosthesis and patient levels.
RESULTS
The records of 37 patients (284 implants and 43 prostheses) were included in the study. At the last follow-up (45.5 ±33.6 months), the prosthetic success rate was 100%. Mucositis affected 4 implants (1.4%), while peri-implantitis affected 4 implants (1.4%). Meanwhile, 7 implants (2.5%) showed a lack of early osseointegration. According to the criteria of Albrektsson et al., 271 implants (95.4%) were successful. The average MBL at the implant, prosthesis and patient levels was 0.26 ±0.42 mm, 0.26 ±0.19 mm and 0.26 ±0.18 mm, respectively.
CONCLUSIONS
The technique described in this article seems to be a viable approach to the rehabilitation of totally edentulous patients through immediate loading. However, these results should be confirmed by appropriately designed prospective and comparative clinical studies.
Topics: Dental Implants; Dental Prosthesis, Implant-Supported; Humans; Jaw, Edentulous; Mouth, Edentulous; Prospective Studies; Retrospective Studies; Welding
PubMed: 36098486
DOI: 10.17219/dmp/149470 -
Journal of Neuroengineering and... Mar 2022Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone anchoring implants, where osseointegration defines the biological... (Review)
Review
Electrical stimulation has shown to be a promising approach for promoting osseointegration in bone anchoring implants, where osseointegration defines the biological bonding between the implant surface and bone tissue. Bone-anchored implants are used in the rehabilitation of hearing and limb loss, and extensively in edentulous patients. Inadequate osseointegration is one of the major factors of implant failure that could be prevented by accelerating or enhancing the osseointegration process by artificial means. In this article, we reviewed the efforts to enhance the biofunctionality at the bone-implant interface with electrical stimulation using the implant as an electrode. We reviewed articles describing different electrode configurations, power sources, and waveform-dependent stimulation parameters tested in various in vitro and in vivo models. In total 55 English-language and peer-reviewed publications were identified until April 2020 using PubMed, Google Scholar, and the Chalmers University of Technology Library discovery system using the keywords: osseointegration, electrical stimulation, direct current and titanium implant. Thirteen of those publications were within the scope of this review. We reviewed and compared studies from the last 45 years and found nonuniform protocols with disparities in cell type and animal model, implant location, experimental timeline, implant material, evaluation assays, and type of electrical stimulation. The reporting of stimulation parameters was also found to be inconsistent and incomplete throughout the literature. Studies using in vitro models showed that osteoblasts were sensitive to the magnitude of the electric field and duration of exposure, and such variables similarly affected bone quantity around implants in in vivo investigations. Most studies showed benefits of electrical stimulation in the underlying processes leading to osseointegration, and therefore we found the idea of promoting osseointegration by using electric fields to be supported by the available evidence. However, such an effect has not been demonstrated conclusively nor optimally in humans. We found that optimal stimulation parameters have not been thoroughly investigated and this remains an important step towards the clinical translation of this concept. In addition, there is a need for reporting standards to enable meta-analysis for evidence-based treatments.
Topics: Animals; Bone-Implant Interface; Electric Stimulation; Humans; Osseointegration; Prostheses and Implants; Surface Properties; Titanium
PubMed: 35313892
DOI: 10.1186/s12984-022-01005-7 -
Trends in Biotechnology Aug 2021Recent research in tissue engineering and regenerative medicine has elucidated the importance of the matrisome. The matrisome, effectively the skeleton of an organ,... (Review)
Review
Recent research in tissue engineering and regenerative medicine has elucidated the importance of the matrisome. The matrisome, effectively the skeleton of an organ, provides physical and biochemical cues that drive important processes such as differentiation, proliferation, migration, and cellular morphology. Leveraging the matrisome to control these and other tissue-specific processes will be key to developing transplantable bioprosthetics. In the ovary, the physical and biological properties of the matrisome have been implicated in controlling the important processes of follicle quiescence and folliculogenesis. This expanding body of knowledge is being applied in conjunction with new manufacturing processes to enable increasingly complex matrisome engineering, moving closer to emulating tissue structure, composition, and subsequent functions which can be applied to a variety of tissue engineering applications.
Topics: Cellular Microenvironment; Extracellular Matrix; Female; Humans; Ovary; Prostheses and Implants; Regenerative Medicine; Tissue Engineering
PubMed: 33593603
DOI: 10.1016/j.tibtech.2021.01.008 -
Sensors (Basel, Switzerland) Jun 2023A retinal prosthesis, also known as a bionic eye, is a device that can be implanted to partially restore vision in patients with retinal diseases that have resulted in... (Review)
Review
A retinal prosthesis, also known as a bionic eye, is a device that can be implanted to partially restore vision in patients with retinal diseases that have resulted in the loss of photoreceptors (e.g., age-related macular degeneration and retinitis pigmentosa). Recently, there have been major breakthroughs in retinal prosthesis technology, with the creation of numerous types of implants, including epiretinal, subretinal, and suprachoroidal sensors. These devices can stimulate the remaining cells in the retina with electric signals to create a visual sensation. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 is conducted. This narrative review delves into the retinal anatomy, physiology, pathology, and principles underlying electronic retinal prostheses. Engineering aspects are explored, including electrode-retina alignment, electrode size and material, charge density, resolution limits, spatial selectivity, and bidirectional closed-loop systems. This article also discusses clinical aspects, focusing on safety, adverse events, visual function, outcomes, and the importance of rehabilitation programs. Moreover, there is ongoing debate over whether implantable retinal devices still offer a promising approach for the treatment of retinal diseases, considering the recent emergence of cell-based and gene-based therapies as well as optogenetics. This review compares retinal prostheses with these alternative therapies, providing a balanced perspective on their advantages and limitations. The recent advancements in retinal prosthesis technology are also outlined, emphasizing progress in engineering and the outlook of retinal prostheses. While acknowledging the challenges and complexities of the technology, this article highlights the significant potential of retinal prostheses for vision restoration in individuals with retinal diseases and calls for continued research and development to refine and enhance their performance, ultimately improving patient outcomes and quality of life.
Topics: Humans; Quality of Life; Retina; Retinal Diseases; Visual Prosthesis; Biomedical Engineering; Electrodes, Implanted; Patient Selection; Treatment Outcome
PubMed: 37447632
DOI: 10.3390/s23135782