Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 43.376
Filtrar
1.
Br J Radiol ; 93(1105): 20190069, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31642702

RESUMO

OBJECTIVE: To evaluate the impact of different metal artifact reduction (MAR) algorithms on Hounsfield unit (HU) and standardized uptake values (SUV) in a phantom setting and verify these results in patients with metallic implants undergoing oncological PET/CT examinations. METHODS AND MATERIALS: In this prospective study, PET-CT examinations of 28 oncological patients (14 female, 14 male, mean age 69.5 ± 15.2y) with 38 different metal implants were included. CT datasets were reconstructed using standard weighted filtered back projection (WFBP) without MAR, MAR in image space (MARIS) and iterative MAR (iMAR, hip algorithm). The three datasets were used for PET attenuation correction. SUV and HU measurements were performed at the site of the most prominent bright and dark band artifacts. Differences between HU and SUV values across the different reconstructions were compared using paired t-tests. Bonferroni correction was used to prevent alpha-error accumulation (p < 0.017). RESULTS: For bright band artifacts, MARIS led to a non-significant mean decrease of 12.0% (345 ± 315 HU) in comparison with WFBP (391 ± 293 HU), whereas iMAR led to a significant decrease of 68.3% (125 ± 185 HU, p < 0.017). For SUVmean, MARIS showed no significant effect in comparison with WFBP (WFBP: 0.99 ± 0.40, MARIS: 0.96 ± 0.39), while iMAR led to a significant decrease of 11.1% (0.88 ± 0.35, p < 0.017). Similar results were observed for dark band artifacts. CONCLUSION: iMAR significantly reduces artifacts caused by metal implants in CT and thus leads to a significant change of SUV measurements in bright and dark band artifacts compared with WFBP and MARIS, thus probably improving PET quantification. ADVANCES IN KNOWLEDGE: The present work indicates that MAR algorithms such as iMAR algorithm in integrated PET/CT scanners are useful to improve CT image quality as well as PET quantification in the evaluation of tracer uptake adjacent to large metal implants. A detailed analysis of oncological patients with various large metal implants using different MAR algorithms in PET/CT has not been conducted yet.


Assuntos
Artefatos , Metais , Tomografia Computadorizada com Tomografia por Emissão de Pósitrons/métodos , Próteses e Implantes , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Idoso , Algoritmos , Feminino , Fluordesoxiglucose F18 , Humanos , Masculino , Imagens de Fantasmas , Estudos Prospectivos , Compostos Radiofarmacêuticos
4.
Int J Oral Maxillofac Implants ; 34(34): 1389-1396, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31711080

RESUMO

PURPOSE: This study represents a systematic review of the literature to assess the effectiveness of strontium-coated titanium surfaces on osseointegration in experimental assays with healthy, nonosteoporotic and/or nonosteopenic animals. MATERIALS AND METHODS: An electronic search was conducted of the databases MEDLINE/PubMed, Wiley Library, and Web of Science through 2018, with the aim of identifying studies on the osseointegration of titanium implants modified with strontium. RESULTS: A total of 255 papers were found, of which 11 were included in this systematic review. The primary result was the percentage of bone-to-implant contact (BIC) around the titanium implants with or without a strontium-coated surface. The different techniques used to coat titanium surfaces with strontium recorded significant results in terms of the improvement in the implant's quality, as they increased its contact with the bone, bone area, and bone formation, as well as enhanced its biomechanical properties. CONCLUSION: Nine of 11 studies reported that titanium implants coated with strontium showed significantly higher BIC (P < .001 to P < .05). This coating also improved the implants' biomechanical properties.


Assuntos
Implantes Dentários , Osseointegração , Estrôncio , Titânio , Animais , Materiais Revestidos Biocompatíveis , Modelos Animais , Próteses e Implantes , Propriedades de Superfície
5.
Nature ; 575(7781): 169-174, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31666696

RESUMO

Two dry surfaces can instantly adhere upon contact with each other through intermolecular forces such as hydrogen bonds, electrostatic interactions and van der Waals interactions1,2. However, such instant adhesion is challenging when wet surfaces such as body tissues are involved, because water separates the molecules of the two surfaces, preventing interactions3,4. Although tissue adhesives have potential advantages over suturing or stapling5,6, existing liquid or hydrogel tissue adhesives suffer from several limitations: weak bonding, low biological compatibility, poor mechanical match with tissues, and slow adhesion formation5-13. Here we propose an alternative tissue adhesive in the form of a dry double-sided tape (DST) made from a combination of a biopolymer (gelatin or chitosan) and crosslinked poly(acrylic acid) grafted with N-hydrosuccinimide ester. The adhesion mechanism of this DST relies on the removal of interfacial water from the tissue surface, resulting in fast temporary crosslinking to the surface. Subsequent covalent crosslinking with amine groups on the tissue surface further improves the adhesion stability and strength of the DST. In vitro mouse, in vivo rat and ex vivo porcine models show that the DST can achieve strong adhesion between diverse wet dynamic tissues and engineering solids within five seconds. The DST may be useful as a tissue adhesive and sealant, and in adhering wearable and implantable devices to wet tissues.


Assuntos
Adesividade , Adesivos/química , Coração , Pulmão , Próteses e Implantes , Estômago , Molhabilidade , Resinas Acrílicas/química , Animais , Quitosana/química , Reagentes para Ligações Cruzadas/química , Dessecação , Gelatina/química , Coração/anatomia & histologia , Hidrogéis/química , Ligações de Hidrogênio , Pulmão/anatomia & histologia , Pulmão/química , Camundongos , Ratos , Eletricidade Estática , Estômago/anatomia & histologia , Estômago/química , Suínos , Fatores de Tempo , Água/análise , Água/química , Dispositivos Eletrônicos Vestíveis
6.
Medicine (Baltimore) ; 98(45): e17935, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31702680

RESUMO

BACKGROUND: Recently, many kinds of cages for cervical fusion have been developed to avoid the related complications caused by tricortical iliac crest graft. The existing literature has reported the excellent clinical efficacy and superior fusion rate. However, various types of cages have their own disadvantages. Which bone graft material is the best choice for cage with the fewest complications? At present, there is still no conclusion. METHODS: By reviewing patients with 1 to 2-level cervical degenerative disease in our hospital with a novel cage made of allograft or polyetheretherketone (PEEK), we evaluated the efficacy and reliability of the new cage in anterior cervical discectomy and fusion (ACDF). From 2015 to 2016, a prospective review of 58 and 49 consecutive cases with spondylotic radiculopathy or myelopathy undergoing ACDF using allograft (group A) and PEEK (group B) cage were performed. The follow-up ranged from 12 to 40 months. Intraoperative index, clinical outcome and complications were recorded. Radiographs evaluated segmental and overall cervical lordosis, the height of the intervertebral space, interbody height ratio (IHR), cage positioning, and fusion state. RESULTS: A total of 134 cages were implanted. Compared to preoperatively, the visual analog scale (VAS) and neck disability index (NDI) were reduced postoperatively without any change during the subsequent follow-up in both groups. There was no migration or extrusion of the cages at the latest follow-up. There were 2 and 4 patients suffering dysphagia respectively. In both groups, the intervertebral height, IHR, segmental and overall cervical lordosis were significantly greater than pre-operation (P < .05) and were maintained at the last follow-up, but were not statistically significant (P > .05). The allograft group achieved a fusion rate of 100% (58/58) according to CT scans at 3 months post-operation, while PEEK group was 91.8% (45/49), which reached 95.9% (47/49) at 6 months and 100% at 12 months. In addition, the fusion state was maintained in all patients at the last follow-up. CONCLUSION: Our data showed that the new allograft cage is superior to the PEEK cage in providing a high fusion rate and fewer complications after 1-level and 2-level ACDF procedures. It may represent an excellent alternative to other cages.


Assuntos
Aloenxertos/transplante , Discotomia/métodos , Fixadores Internos , Degeneração do Disco Intervertebral/cirurgia , Cetonas/uso terapêutico , Polietilenoglicóis/uso terapêutico , Fusão Vertebral/métodos , Adulto , Feminino , Humanos , Degeneração do Disco Intervertebral/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados não Aleatórios como Assunto , Próteses e Implantes , Resultado do Tratamento
7.
Adv Exp Med Biol ; 1101: 91-122, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31729673

RESUMO

Peripheral nervous system, widely spread in the whole body, is the important bridge for the transmission of neural signals. Signals from the central nervous system (brain and spinal cord) are transmitted to different parts of the body by the peripheral nerves, while along the way they also feedback all kinds of sensory information. Certain level of information integration and processing also occurs in the system. It has been shown that neural signals could be extracted from the distal end of the stump, indicating that the bridge is still effective after limb damage or amputation, which is the neurophysiological basis for the research and development of peripheral nerve interface for the prosthetic system.


Assuntos
Nervos Periféricos , Transdução de Sinais , Sistema Nervoso Central , Humanos , Regeneração Nervosa , Nervos Periféricos/fisiologia , Próteses e Implantes , Medula Espinal
8.
Adv Exp Med Biol ; 1101: 225-241, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31729678

RESUMO

The technological ability to capture electrophysiological activity of populations of cortical neurons through chronic implantable devices has led to significant advancements in the field of brain-computer interfaces. Recent progress in the field has been driven by developments in integrated microelectronics, wireless communications, materials science, and computational neuroscience. Here, we review major device development landmarks in the arena of neural interfaces from FDA-approved clinical systems to prototype head-mounted and fully implantable wireless systems for multi-channel neural recording. Additionally, we provide an outlook toward next-generation, highly miniaturized technologies for minimally invasive, vastly parallel neural interfaces for naturalistic, closed-loop neuroprostheses.


Assuntos
Interfaces Cérebro-Computador , Próteses e Implantes , Interfaces Cérebro-Computador/tendências , Desenho de Equipamento/tendências , Humanos , Neurônios , Neurociências , Próteses e Implantes/tendências
9.
Medicine (Baltimore) ; 98(47): e18022, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31764819

RESUMO

This retrospective study investigated the effect of the novel bone graft transverse process strut (TPS) in single segmental thoracic spinal tuberculosis (TB) with the one-stage posterior approach of debridement, fusion, and internal instrumentation. Thirty patients treated in our department from March 2014 to October 2016 were retrospectively analyzed. Surgical time, blood loss, hospitalization time, drainage volume, and follow-up (FU) duration were recorded. The visual analog scale (VAS), Oswestry Disability Index (ODI), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), American Spinal Injury Association (ASIA) grade, segmental angle, and bone fusion were compared between preoperative and final FU. All the patients were followed for a mean 50.10 ±â€Š25.10 months; the mean age, surgical time in minutes, blood loss, hospitalization time, and drainage volume were 46.23 ±â€Š17.20 years, 195.08 ±â€Š24.0 minutes, 280.77 ±â€Š189.90 mL, 17.31 ±â€Š4.23 days, 436.92 ±â€Š193.81 mL, respectively. VAS and ODI scores were significantly improved at the final FU. The ESR and CRP returned to normal. All patients achieved bony fusion with a mean time of 5.85 ±â€Š1.82 months and a mean segmental angle of 18.77 ±â€Š2.49° preoperatively, which significantly decreased to 9.31 ±â€Š1.54° at the final FU (P < .05). No complications, such as bone graft failure, pleural effusion, fistula, or wound infection were recorded except for cerebrospinal fluid leakage (one case), water electrolyte imbalance (5 cases), superficial infection (1 case), and mild intestinal obstruction (1 case). TPS as a bone graft is reliable, safe, and effective for segmental stability reconstruction for surgical management of single-segment thoracic spinal TB.


Assuntos
Desbridamento/métodos , Próteses e Implantes , Vértebras Torácicas/cirurgia , Tuberculose da Coluna Vertebral/cirurgia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
11.
Radiologe ; 59(10): 875-884, 2019 Oct.
Artigo em Alemão | MEDLINE | ID: mdl-31591698

RESUMO

METHODICAL INNOVATIONS: In the present article, interactions associated with magnetic resonance (MR) procedures and MR test procedures for implants/devices are examined. PERFORMANCE: Since 2012, many interactions of items with MR procedures have been physically described and translated into standardized ASTM and ISO testing procedures. Despite the standardized procedures, the determination of the test method to use is an important decision. The MR user is also responsible for the transfer and interpretation of the individual technical parameters despite the MR Conditional labelling and therefore relatively unambiguous instruction. This includes the total MR examination duration, which often has no clinical practical duration, but is derived from the 15 min of the ASTM radiofrequency (RF) heating test. ACHIEVEMENTS: There has been an increasing standardization of the test methods as well as the MR labeling requirements and the advantageous transfer of the parameters to suitable input masks on the MR systems. PRACTICAL RECOMMENDATIONS: The current use of standardized MR test methods and MR marking represents the best possible state of the art from the point of view of the approval of medical devices as well as from a liability point of view for the manufacturers of implants-and for MR users in clinical practice. However, off-label decisions (i.e., deviations from the manufacturer's official MR marking) in everyday clinical practice can be medically justified.


Assuntos
Imagem por Ressonância Magnética , Próteses e Implantes , Segurança de Equipamentos , Espectroscopia de Ressonância Magnética , Rotulagem de Produtos
12.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 54(10): 670-675, 2019 Oct 09.
Artigo em Chinês | MEDLINE | ID: mdl-31607002

RESUMO

Objective: To explore the optimal method of microelectrode implantation that can produce efficient mouth closure with microelectrode for orbicularis oris muscle (OOM) in rhesus monkeys with unilateral peripheral facial paralysis (UPFP) in order to provide basis for the research and development of artificial facial nerve prosthesis (AFNP). Methods: Right lateral peripheral facial paralysis model on four healthy rhesus monkeys (two males and two femles, aged 5-6 years, weighed 2.0-3.0 kg) were prepared. AFNP electric stimulation was used to induce closed-mouth reaction of the affected OOM with a one-way rectangular pulse, 50 Hz frequency and 0.2 ms pulse width in vitro. Around the affected lateral OOM, four stimulus electrodes implantation positions were selected at the upper lip (position A), the lower lip (position B), the connection with the corner of the mouth to the ipsilateral tragus (position C), and the horizontal line of the mouth angle (position D). According to the different implantation positions of three stimulation electrodes on the stimulation side of AFNP and the results of our previous study, six groups of microelectrode implantation methods were designed. In Group A, two microelectrodes were implanted at position A and one microelectrode was implanted at position B; in Group B, one microelectrode was implanted at position A, B and C respectively; in Group C, one microelectrode was implanted at position A and two microelectrodes were implanted at position B; in Group D, one microelectrode was implanted at position A, B and D respectively; in Group E, one microelectrode was implanted at position A, C and D respectively; in Group F, one microelectrode was implanted at position B, C and D respectively. The minimum stimulating current (threshold current) required for effective mouth closure were recorded. The threshold and peak current values were compared using one-way ANOVA and LSD-t multiple comparisons. Results: The microelectrodes of the AFNP stimulating side in Group E and F failed to induce a smooth mouth closure. The microelectrodes in A, B, C and D group induced smooth mouth closure. The threshold current value of OOM contraction on affected side in the Group A, B, C, and D were (1.35±0.05), (1.02±0.04), (1.40±0.04) and (1.10±0.02) mA, respectively (F=295.302, P<0.001), with the lowest value in Group B and there was significant difference between the current value in Group B and those in the other groups (all P<0.05). The peak current value of OOM contraction on affected side in the four groups were (3.95±0.02), (2.95±0.03), (3.99±0.05) and (3.51±0.01) mA, respectively (F=1 014.985, P<0.001). Group B showed the best lip-closure morphology observed with naked eyes. Conclusions: When three output microelectrode of the AFNP stimulated side are separately imbedded into the upper lip, the lower lip and the connection with the corner of the mouth to the ipsilateral tragus, AFNP can sufficiently induce closed-mouth reaction. These positions are suitable as priority options microelectrodes implantation positions for the microelectrodes of the AFNP stimulated side.


Assuntos
Paralisia Facial , Microeletrodos , Próteses e Implantes , Animais , Músculos Faciais , Nervo Facial , Paralisia Facial/terapia , Lábio , Macaca mulatta , Masculino
13.
Gan To Kagaku Ryoho ; 46(10): 1599-1601, 2019 Oct.
Artigo em Japonês | MEDLINE | ID: mdl-31631148

RESUMO

A man in his 40s presented with fever and nasal congestion. NK-T cell lymphoma was pathologically diagnosed. A central venous(CV)port was implanted via a right subclavian approach. Four months later, redness and swelling were observed around the implanted CV port. Initially, an infection of the CV port was suspected, and the CV port was removed. Regardless of the removal of the port, the wound healing was refractory, and an ulcer formed. Surgical biopsy from the ulcer showed skin infiltration of NK-T cell lymphoma. In cases ofref ractory wound healing around an implanted CV port in patients with lymphoma, lymphoma recurrence and port infection should be considered.


Assuntos
Cateterismo Venoso Central , Linfoma , Biópsia , Bases de Dados Genéticas , Humanos , Masculino , Próteses e Implantes , Recidiva
14.
Int J Nanomedicine ; 14: 7217-7236, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31564875

RESUMO

Prosthesis-associated infections are one of the main causes of implant failure; thus it is important to enhance the long-term antibacterial ability of orthopedic implants. Titanium dioxide nanotubes (TNTs) are biomaterials with good physicochemical properties and biocompatibility. Owing to their inherent antibacterial and drug-loading ability, the antibacterial application of TNTs has received increasing attention. In this review, the process of TNT anodizing fabrication is summarized. Also, the mechanism and the influencing factors of the antibacterial property of bare TNTs are explored. Furthermore, different antibacterial strategies for carrying drugs, as well as modifications to prolong the antibacterial effect and reduce drug-related toxicity are discussed. In addition, antibacterial systems based on TNTs that can automatically respond to infection are introduced. Finally, the currently faced problems are reviewed and potential solutions are proposed. This review provides new insight on TNT fabrication and summarizes the most advanced antibacterial strategies involving TNTs for the enhancement of long-term antibacterial ability and reduction of toxicity.


Assuntos
Antibacterianos/farmacologia , Nanotubos/química , Ortopedia , Próteses e Implantes , Titânio/farmacologia , Antibacterianos/química , Humanos , Propriedades de Superfície
19.
Kyobu Geka ; 72(10): 799-804, 2019 Sep.
Artigo em Japonês | MEDLINE | ID: mdl-31582699

RESUMO

Ventricular septal defect is the most frequent congenital heart disease and it exists as an isolated form or combines with other complex cardiovascular malformations. Soto's classification is based on the location and extension of the defect and it is most useful and comprehensive for a surgeon. Ventricular septal defect closure is one of the basic surgical procedures that a congenital heart surgeon must master first. In order to perform a perfect patch closure of the defect without making complications such as residual interventricular shunt, tricuspid valve regurgitation, or atrioventricular block, surgeon must acquire, ① preoperative and intraoperative accurate assessment and understanding of the anatomical features of the defect, ② effective intraoperative exposure of the defect, and ③ safe and assured stitch and ligation.


Assuntos
Comunicação Interventricular , Insuficiência da Valva Tricúspide , Comunicação Interventricular/cirurgia , Humanos , Próteses e Implantes
20.
Arq. bras. med. vet. zootec. (Online) ; 71(5): 1535-1540, set.-out. 2019. ilus, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1038647

RESUMO

The objective of this study was to develop a locked tibial-plateau-leveling osteotomy (TPLO) plate and to compare this implant with the conventional bone fixation method using a locked plate to determine bone stabilization against torsion forces. Maximum force, angle at peak torque, and stiffness values were determined. Ten synthetic tibias were used, divided into 2 groups. The results in Group 1 (modified TPLO plate) and Group 2 (locked plate) were assessed using analysis of variance and the means were compared using Tukey's test at 5% probability. There were significant differences in the angle at peak torque and stiffness. The group Modified TPLO plate had higher mean values of stiffness compared with Group locked plate. Group locked plate showed a greater angle at peak torque compared with Group modified TPLO plate. All constructs failed due to tibial fractures distal to the plate. The modified TPLO plate presented higher stiffness indexes than conventional locked plate in torsion. The locked plate presented greater elasticity than modified TPLO plate having greater angle at the peak of torque.(AU)


O objetivo do presente estudo foi desenvolver placa de TPLO bloqueada modificada e avaliar, em ensaio de torção, a estabilização óssea proporcionada pelo implante desenvolvido comparativamente a método de fixação óssea convencional com placa reta bloqueada. As variáveis obtidas foram força máxima, ângulo no pico de torque e rigidez. Foram utilizadas 10 tíbias sintéticas, dividas em dois grupos. Os resultados obtidos do grupo 1 (placa TPLO modificada) e do grupo 2 (placa bloqueada) foram submetidos à análise de variância, e as médias comparadas entre si pelo teste de Tukey a 5% de probabilidade. Houve diferença significativa em relação às variáveis, ângulo no pico de torque e rigidez. Na variável rigidez, a média do grupo placa de TPLO modificada foi maior que a do grupo placa reta bloqueada. Em relação à variável ângulo no pico de torque, o grupo placa reta bloqueada foi superior ao grupo placa de TPLO modificada. Todas as montagens falharam devido à quebra do corpo de prova distal à placa. Conclui-se que a placa de TPLO modificada apresentou maior índice de rigidez que a placa reta convencional sob força de torção. A placa reta bloqueada apresentou maior ângulo no pico de torque, sendo, portando, mais elástica.(AU)


Assuntos
Animais , Cães , Próteses e Implantes/veterinária , Procedimentos Ortopédicos/veterinária , Fixação Interna de Fraturas/métodos , Fixação Interna de Fraturas/veterinária , Tíbia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA