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Prosthetic Devices (prosthetic + device)

Distribution by Scientific Domains

Medical Sciences	41%
Life Sciences	25%
Engineering	16%

Selected Abstracts

New insight into the mechanism of hip prosthesis loosening: Effect of titanium debris size on osteoblast function

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2004
Daniel T. O'Connor
Abstract The incidence of rheumatoid arthritis and osteoarthritis is on the rise due to our expanding elderly population. Total joint arthroplasty is the most successful, prevalent treatment modality for these and other degenerative hip conditions. Despite the wide array of prosthetic devices commercially available, hip prostheses share a common problem with a gradual and then accelerating loss of bone tissue and bone,implant interface integrity, followed by implant instability and loosening. Implant failure is largely the result of inevitable wear of the device and generation of wear debris. To provide information for the development of improved prosthetic wear characteristics, we examined the effects of size-separated titanium particles on bone forming cell populations. We demonstrate unequivocally that particle size is a critical factor in the function, proliferation, and viability of bone-forming osteoblasts in vitro. In addition, we have elucidated the time-dependent distribution of the phagocytosed particles within the osteoblast, indicating an accumulation of particles in the perinuclear area of the affected cells. The report finds that particle size is a critical factor in changes in the bone formation-related functions of osteoblasts exposed to simulate wear debris, and that 1.5,4 ,m titanium particles have the greatest effect on osteoblast proliferation and viability in vitro. The size of titanium particles generated through wear of a prosthetic device may be an important consideration in the development of superior implant technology. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]

D-Tower, NOX, Doetinchem, the Netherlands, 1998,2004 and Son-O-House, Son en Breugel, NOX, the Netherlands, 2000,2004

ARCHITECTURAL DESIGN, Issue 1 2005
Lucy Bullivant
Abstract Conducting your love life or expressing your innermost feelings through an architectural medium, one that seemingly replaces the traditional village green where people met up and shared experiences, is a pretty far-reaching social proposition. But D-Tower, a collaboration between architect Lars Spuybroek of NOX in Rotterdam, and QS Serafijn, a Rotterdam-based artist, aims to do just that, writes Lucy Bullivant, in a way that transcends any notion of a pure prosthetic device with an architectural system of communication. Lars Spuybroek of NOX has also recently made public artwork for Industrieschap Ekkersrijt, in collaboration with composer Edwin van der Heide. Here, Lucy Bullivant describes a project that builds a ,memoryscape' of sounds in and near the space visitors participate in making. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Retinal and Optic Nerve Diseases

ARTIFICIAL ORGANS, Issue 11 2003
Eyal Margalit
Abstract:, A variety of disease processes can affect the retina and/or the optic nerve, including vascular or ischemic disease, inflammatory or infectious disease, and degenerative disease. These disease processes may selectively damage certain parts of the retina or optic nerve, and the specific areas that are damaged may have implications for the design of potential therapeutic visual prosthetic devices. Outer retinal diseases include age-related macular degeneration, pathologic myopia, and retinitis pigmentosa. Although the retinal photoreceptors may be lost, the inner retina is relatively well-preserved in these diseases and may be a target for retinal prosthetic devices. Inner retinal diseases include retinal vascular diseases such as diabetic retinopathy, retinal venous occlusive disease, and retinopathy of prematurity. Other retinal diseases such as ocular infections (retinitis, endophthalmitis) may affect all retinal layers. Because the inner retinal cells, including the retinal ganglion cells, may be destroyed in these diseases (inner retinal or whole retinal), prosthetic devices that stimulate the inner retina may not be effective. Common optic nerve diseases include glaucoma, optic neuritis, and ischemic optic neuropathy. Because the ganglion cell nerve fibers themselves are damaged, visual prosthetics for these diseases will need to target more distal portions of the visual pathway, such as the visual cortex. Clearly, a sound understanding of retinal and optic nerve disease pathophysiology is critical for designing and choosing the optimal visual prosthetic device. [source]

Multicentre retrospective analysis of the outcome of artificial anal sphincter implantation for severe faecal incontinence

BRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 11 2001
Dr D. F. Altomare
Background: A new prosthetic device, the ActiconTM artificial anal sphincter, has recently been introduced for treating severe faecal incontinence. The results of this procedure in 28 patients are presented. Methods: The patients underwent operation for severe faecal incontinence in four Italian university hospitals and patients were reviewed after a median follow-up of 19 (range 7,41) months. Results: Early infections occurred in four patients, requiring removal of the device in three. Dehiscence of the perineal wound occurred in nine patients. After activation of the device, the cuff had to be removed in a further four patients (for rectal erosion in two, anal pain in one and late infection in one). The cuff was accidentally broken in one patient. A new anal cuff was repositioned successfully in two patients. Overall, five patients had complete removal of the device and two removal of the cuff only. Twenty-one patients available for long-term evaluation had a major improvement in faecal continence. Median resting anal pressure increased from 27 mmHg before surgery to 32 mmHg after operation. Preoperative squeeze pressure was 42 mmHg while maximum postoperative anal pressure with the activated device was 67 mmHg. The median American Medical System incontinence score decreased significantly from 98·5 to 5·5 (P < 0·001). Similar figures were observed using the Continence Grading Scale (from 14·9 to 2·6; P < 0·001). Twelve patients developed symptoms of obstructed defaecation while two patients complained of anal pain. Conclusion: Improved continence was achieved after neosphincter implantation in three-quarters of the patients. Early infection and rectal erosion, together with difficulty in evacuating, are still major concerns with this technique. © 2001 British Journal of Surgery Society Ltd [source]

Evidence of amputation as medical treatment in ancient Egypt

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 4 2010
T. L. Dupras
Abstract The use of surgical techniques in ancient Egyptian medicine has only been suggested indirectly through ancient medical texts and iconography, and there is no evidence of amputation as a means of therapeutic medical treatment. This paper presents four cases of amputation from the archaeological site of Dayr al-Barsh,, Egypt. Two of the cases (dated to the First Intermediate and Middle Kingdom periods, respectively) are from individuals that display bilateral amputations of the feet, one through the metatarso-phalangeal joints, the other a transmetatarsal amputation. The exact reason for the amputation, perhaps from trauma or disease, is unknown. The particular healing patterns of the distal ends of the amputations suggest these individuals used foot binding or prosthetic devices. Another case represents a healed amputation of the left ulna near the elbow, dated to the Old Kingdom. The final case represents a perimortem amputation of the distal end of the right humerus. The exact date of this individual is unknown, but most likely pertains to the Old Kingdom or First Intermediate period. This individual seems to have suffered a traumatic incident shortly before death, sustaining many fractures, including a butterfly fracture on the right humerus. Several cut marks were identified on top of the butterfly fracture, indicating amputation of the arm at this point. All four cases support the hypothesis that the ancient Egyptians did use amputation as a therapeutic medical treatment for particular diseases or trauma. Copyright © 2009 John Wiley & Sons, Ltd. [source]

New insight into the mechanism of hip prosthesis loosening: Effect of titanium debris size on osteoblast function

In vitro new dialysis protocol to assay the antiseptic properties of a quaternary ammonium compound polymerized with denture acrylic resin

LETTERS IN APPLIED MICROBIOLOGY, Issue 3 2004
C. Pesci-Bardon
Abstract Aims:, To develop an in vitro protocol in order to assess the antiseptic properties of a quaternary ammonium compound polymerized with acrylic denture resin base, using experimental resin discs and dialysis membranes. Methods and Results:, Experimental acrylic resin discs were polymerized with Poly 202063A, an ammonium compound (2,50%). Antiseptic properties were assayed against two reference strains (Escherichia coli, Staphylococcus aureus) and a laboratory strain (Candida albicans), using three different conditions (test A, B and C). In test A, according to classical protocols the resin discs were first soaked in large volumes of microbial inoculum (45 ml). An original dialysis protocol was then designed to recreate the small biofilm volume on the prosthetic surface. In test B, discs and bacterial inoculum (600 ,l) were introduced in a dialysis bag and dialysed against a sterile buffer. A bactericidal effect was observed against E. coli and Staph. aureus (<0·1% viable cells in initial bacterial suspension). A dose-dependent fungistatic effect was observed against C. albicans. Finally, in test C discs and sterile buffer (600 ,l) were introduced in a dialysis bag and dialysed against microbial inoculum. Reduced activity was found outside the dialysis bag, demonstrating that free ammonium was able to diffuse through the dialysis membrane, displaying antiseptic properties. Conclusions:, The present protocol demonstrated that a quaternary ammonium compound remains efficient after heat polymerization with an acrylic denture base resin, both in immediate and distant microbial environments. Significance and Impact of the Study:, Such removable prosthetic devices with intrinsic antiseptic properties would contribute to improve the long-term management of denture stomatitis. [source]

Electro-synthesized PEDOT/glutamate chemically modified electrode: a combination of electrical and biocompatible features

POLYMER INTERNATIONAL, Issue 5 2008
Jianfei Che
Abstract BACKGROUND: Neural prosthetic devices have been developed that can facilitate the stimulation and recording of electrical activity when implanted in the central nervous system. The key parts of the devices are metal (gold) electrodes; however, surface modification of the gold electrode is desired. Conducting polymers are promising candidates for this purpose. RESULTS: A conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was electro-polymerized onto gold electrodes with a neural transmitter of glutamate (Glu) as dopant. A protocol of ion exchange was employed due to the difficulty of direct incorporation of Glu into PEDOT. Sodium p -toluenesulfonate (TSNa) was chosen as the first dopant and subsequent incorporation of Glu was accomplished via ion exchange. The electrochemical properties of the resultant PEDOT/Glu were studied using electrochemical impedance spectroscopy and cyclic voltammetry. The purpose of incorporating Glu was to improve the biocompatibility of the coated electrode. The PEDOT/Glu-coated electrode showed better cell attachment compared with a PEDOT/TSNa-coated electrode in in vitro cell culture of PC12. The stability of PEDOT was studied by immersing the coated electrode in a biologically relevant reducing agent of glutathione. CONCLUSION: The charge capacity of the coated electrode had an initial slight decrease and then remained unchanged. Good electro-activity was conserved, indicating the superior stability of PEDOT in the biological environment. Copyright © 2007 Society of Chemical Industry [source]

Sensitivity Analysis of Human Leg Metabolical Costs

PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2005
Marko Ackermann
The human walking is characterized by skeletal dynamics and muscle excitation patterns minimizing the metabolical energy. This criterion is applied to assess the performance of lower limb prosthetic devices, and to evaluate therapies for patients presenting gait disorders. It is desirable, therefore, to dispose models of the human normal and pathological gaits capable of estimating the metabolical energy expenditure. For the swing phase of normal and pathological gaits a musculoskeletal model of the lower limb is presented to estimate metabolical energy expenditure. The mechanical model has three degrees of freedom and is actuated by eight Hill-type muscle units, and the model for the metabolical costs is adopted from literature. In this paper a combination of inverse and direct dynamics is used, and a sensitivity analysis of the dynamical behavior and the corresponding metabolical costs estimations with respect to parametrized neural excitations is performed. The leg motions are based on experiments in a gait analysis laboratory. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Retinal and Optic Nerve Diseases

Study of the Different Types of Actuators and Mechanisms for Upper Limb Prostheses

ARTIFICIAL ORGANS, Issue 6 2003
Vanderlei O. Del Cura
Abstract: Research in the area of actuators and mechanisms has shown steadily growing technological advances in externally activated upper limb prostheses. From among the actuators, advances include the use of piezoelectric materials, special metal alloys, polymers, and new motor applications, while the advances in mechanisms include mechanical designs based on the anatomy of the human hand and improvements in the way these components are combined. These efforts are aimed at meeting the need for anthropomorphic and functional prosthetic devices that enable patients to carry out basic daily tasks more easily and reduce the rejection rate of prostheses. This article technically discusses the several types of actuators and mechanisms, listing their main characteristics, applications, and advantages and disadvantages, and the current state of research in the area of rehabilitation of upper limb functions through the use of active prostheses. Comparisons of these devices are made with regard to the main criteria of construction and operation required to achieve optimal prosthetic performance. [source]