In Vitro Assessment of the Neuro-Compatibility of Fe-20Mn as a Potential Bioresorbable Material for Craniofacial Surgery.

Background and Objectives: Spring-assisted surgery is a popular option for the treatment of non-syndromic craniosynostosis. The main drawback of this procedure is the need for a second surgery for spring removal, which could be avoided if a distractor material could be metabolised over time. Iron-Manganese alloys (FeMn) have a good trade-off between degradation rate and strength; however, their biocompatibility is still debated. Materials and Methods: In this study, the neuro-compatibility of Fe-20Mn (wt.%) was assessed using standard assays. PC-12 cells were exposed to Fe-20Mn (wt.%) and stainless steel via indirect contact. To examine the cytotoxicity, a Cell Tox Green assay was carried out after 1, 2, and 3 days of incubation. Following differentiation, a neurite morphological examination after 1 and 7 days of incubation time was carried out. The degradation response in modified Hank's solution at 1, 3, and 7 days was investigated, too. Results: The cytotoxicity assay showed a higher toxicity of Fe-20Mn than stainless steel at earlier time points; however, at the latest time point, no differences were found. Neurite morphology was similar for cells exposed to Fe-20Mn and stainless steel. Conclusions: In conclusion, the Fe-20Mn alloy shows promising neuro-compatibility. Future studies will focus on in vivo studies to confirm the cellular response to Fe-20Mn.

Implante biodegradável de dexametasona para o tratamento do edema macular diabético em maiores de 18 anos, conforme Protocolo Clínico do Ministério da Saúde / Biodegradable dexamethasone implant for the treatment of diabetic macular edema in people over 18 years of age, according to the Clinical Protocol of the Ministry of Health

INTRODUÇÃO: A retinopatia diabética, a principal causa de cegueira em pessoas em idade laboral, é uma manifestação do diabetes na forma de lesão de órgãos-alvo. Clinicamente, as primeiras lesões são anormalidades vasculares como microaneurismas, hemorragias e exsudatos. O aumento da vasopermeabilidade resulta em espessamento da retina e/ou depósitos lipídicos. Quando esses eventos ocorrem na mácula, instala-se o edema macular diabético (EMD), levando ao risco de perda visual central. Dois mecanismos fundamentais estão envolvidos no EMD: angiogênese e inflamação. A angiogênese é secundária ao aumento da expressão de VEGF, principal molécula envolvida na perda da ruptura da barreira hemato-retiniana, que por sua vez causa a exsudação e espessamento macular. A inflamação pode ser causa ou consequência da angiogênese, atualmente considerada fator interdependente. Citocinas encontram-se elevadas em pacientes com retinopatia diabética e EMD, tendo correlação positiva com a severidade da doença ocular. O PCDT atual de retinopatia diabética, publicado pelo Ministério da Saúde, inclui os antiVEGFs ranibizumabe e aflibercepte para pacientes sem tratamento medicamentoso prévio, associado ou não à fotocoagulação a laser, para o EMD, mas não contempla a corticoterapia para o bloqueio da produção dos mediadores inflamatórios e barreira vascular endotelial. Por este motivo ainda existem necessidades não atendidas no cenário de tratamento das retinopatias diabéticas, especialmente relacionadas ao EMD. De acordo com a literatura, pacientes vitrectomizados, pacientes com eventos tromboembólicos recentes ou que não apresentaram resposta satisfatória ao tratamento com os antiangiogênicos, por exemplo, se encontram desassistidos pelo PCDT, além das dificuldades relacionadas ao regime de aplicações dos anti-VEGFs (injeções frequentes com deslocamentos aos serviços em saúde), complicando o atendimento no SUS. Ainda, relacionado às complicações da retinopatia diabética e qualidade de vida dos pacientes, a falta de tratamento ou tratamento subotimo pode levar à cegueira, além de outras complicações. BREVE HISTÓRICO: Em 2020 a tecnologia foi submetida e teve recomendação desfavorável devido as incertezas frente à ineficácia terapêutica, ausência de evidências robustas e falta de informação sobre delimitação e escopo para uso no SUS. PERGUNTA: O uso do implante intravítreo de dexametasona é seguro e efetivo no tratamento tratamento de adultos com edema macular diabético , como opção terapêutica no SUS? EVIDÊNCIAS CLÍNICAS: As evidências de eficácia e segurança do implante intravítreo de dexametasona são baseadas no estudo pivotal do implante intravítreo de dexametasona e em três estudos de comparação direta com os antiVEGFs, já incorporados ao SUS. O estudo pivotal que comparou o implante de dexametasona ao placebo, utilizando adicionalmente ou não a fotocoagulação a laser, demonstrou melhora da acuidade visual maior ou igual a 15 letras da linha de base do estudo, em ambos os braços de tratamento (DEXi 0,7 e 0,35 mg) em relação ao grupo placebo tratado apenas com fotocoagulação a laser. A melhora significativa no BCVA (do inglês, Best Corrected Visual Acuity) ocorreu independentemente do status do cristalino na linha de base do estudo. Os resultados do primeiro estudo de comparação direta são de não-inferioridade da dexametasona em relação ao ranibizumabe e redução do número de injeções realizadas, com perfil de segurança aceitável. O segundo estudo demonstrou equivalência da dexametasona ao tratamento com aflibercepte, uma vez que a diferença em BCVA não foi clinicamente significativa. O terceiro ECR de comparação direta incluído aponta para a segurança e eficácia em melhorar a BCVA e diminuir a espessura da mácula central, em pacientes com EMD, por ambos os implantes intravítreos (dexametasona vs ranibizumabe). A avaliação da qualidade metodológica dos ECRs foi realizada e os riscos de vieses foram descritos sendo de baixo risco, em sua maioria. AVALIAÇÃO ECONÔMICA: O presente dossiê demonstrou que Ozurdex se configura como uma tecnologia poupadora de recursos para o sistema de saúde, através de apresentação de uma análise de custo-minimização abrangente, que incluiu custos de medicação, custos de administração e custos relativos a potenciais eventos adversos. Através de uma análise de cenários que variou os principais parâmetros tais como horizonte temporal (1 ou 3 anos), e custo de aquisição dos comparadores (anti-VEGFs), valor de APAC (forma de financiamento dos antiangiogênicos) ou custo do frasco-ampola proposto pelos fabricantes em suas solicitações de incorporação, foi possível demonstrar que o tratamento com Ozurdex pode proporcionar economia de recursos que varia de R$ 1.533,21 até R$ 15.651,77 por paciente, em comparação aos anti-VEGFs. ANÁLISE DE IMPACTO ORÇAMENTÁRIO: Na análise de impacto orçamentário, foram avaliados sete cenários com combinações de diferentes valores para os comparadores (APAC e custo frasco-ampola), estimativas populacionais (epidemiológica ou demanda aferida) e dois possíveis comportamentos de market shares. A economia projetada foi de pelo menos R$ 8 milhões, avaliando o cenário mais conservador. Nos demais cenários as economias projetadas foram de R$ 16 e R$ 39 milhões, e entre R$ 148 e R$ 716 milhões em estimativa de usuários consideravelmente maior. Os montantes apresentados podem contribuir para a otimização dos recursos no manejo dos pacientes com RD. MONITORAMENTO DO HORIZONTE TECNOLÓGICO: Foram detectadas 3 tecnologias para compor o esquema terapêutico do edema macular diabético em adultos. São 3 anticorpos monoclonais inibidores do crescimento do endotélio vascular (VEGF): brolucizumabe, faricimabe e tarcocimabe tedromer, sendo que o segundo apresenta também ação anti-angiopoietina 2 (Ang-2). O brolucizumabe e faricimabe estão registrados na FDA e EMA desde 2022. O tarcocimabe está em fase 3 e pode apresentar resultados dos ensaios a partir de 2023. CONSIDERAÇÕES FINAIS: Adicionalmente às evidências clínicas de qualidade, a avaliação de custo-minimização possui e a análise de impacto orçamentário possuem incertezas em relação à definição de custos e cenários de comparação, mas que sugerem dominância do Implante biodegradável de dexametasona para tratamento do edema macular diabético sob a perspectiva do Sistema Único de Saúde. PERSPECTIVA DO PACIENTE: Foi aberta a Chamada Pública nº 09/2022 de 13 a 26 de fevereiro 2022 e duas pessoas se inscreveram, ambas representantes de associações de pacientes. A definição dos representantes titular e suplente foi determinada por decisão consensual entre o grupo de inscritos. A representante leu três relatos de pacientes que possuem edema macular diabético e recorrem ao DEXi. Os três pacientes iniciaram o tratamento com um antiangiogênico e, após o uso do DEXi, apresentaram melhora dos sintomas e o alcance de maior qualidade de vida. Nenhum deles manifestou eventos adversos após o uso do implante. RECOMENDAÇÃO PRELIMINAR: Os membros do plenário, presentes na 118ª Reunião ordinária da Conitec, no dia 03 de maio de 2023, deliberaram por unanimidade encaminhar para a consulta pública com recomendação favorável a incorporação do implante biodegradável de dexametasona para o tratamento do edema macular diabético (EMD) em maiores de 18 anos no SUS. CONSULTA PÚBLICA: Realizada no período de 03 de julho a 24 de julho do presente ano, teve 62 contribuições de caráter técnico-científico e 146 respostas tidas como de experiência ou opinião. As contribuições recebidas na consulta pública sobre o relatório que avalia a proposta de incorporação do Implante biodegradável de dexametasona para o tratamento do edema macular diabético (EMD) em maiores de 18 anos no SUS foram majoritariamente favoráveis a recomendação preliminar da Conitec, de incorporação. Não foram adicionadas na consulta pública, referências que alterassem a análise da evidência apresentada no relatório, apenas atualização pelo demandante. RECOMENDAÇÃO FINAL: Os membros do plenário, presentes na 121ª Reunião ordinária da Conitec, no dia 02 de agosto de 2023, deliberaram por unanimidade recomendar a incorporação do implante biodegradável de dexametasona para o tratamento do edema macular diabético (EMD) em maiores de 18 anos conforme Protocolo Clínico do Ministério da Saúde, sob registro de deliberação 840/2023. Para tal recomendação, levou-se em consideração, entre outros fatores, que há economia de recursos em todos os cenários analisados e que os estudos demostraram que o benefício clínico do implante de dexametasona é maximizado para algumas populações, que atualmente encontram-se desassistidas ou subtratadas devido à ausência de uma opção de corticoterapia no âmbito do SUS. DECISÃO: Incorporar, no âmbito do Sistema Único de Saúde - SUS, o implante biodegradável de dexametasona para o tratamento do edema macular diabético em maiores de 18 anos, conforme Protocolo Clínico do Ministério da Saúde, publicada no Diário Oficial da União nº 193, seção 1, página 143, em 9 de outubro de 2023.

Angiography-Based Superficial Wall Strain of De Novo Stenotic Coronary Arteries: Serial Assessment of Vessels Treated with Bioresorbable Scaffold or Drug-Eluting Stent.

OBJECTIVES: This study sought to present an angiography-based computational model for serial assessment of superficial wall strain (SWS, dimensionless) of de-novo coronary stenoses treated with either bioresorbable scaffold (BRS) or drug-eluting stent (DES). BACKGROUND: A novel method for SWS allows the assessment of the mechanical status of arteries in-vivo, which may help for predicting cardiovascular outcomes. METHODS: Patients with arterial stenosis treated with BRS (n = 21) or DES (n = 21) were included from ABSORB Cohort B1 and AIDA trials. The SWS analyses were performed along with quantitative coronary angiography (QCA) at pre-PCI, post-PCI, and 5-year follow-up. Measurements of QCA and SWS parameters were quantified at the treated segment and adjacent 5-mm proximal and distal edges. RESULTS: Before PCI, the peak SWS on the 'to be treated' segment (0.79 ± 0.36) was significantly higher than at both virtual edges (0.44 ± 0.14 and 0.45 ± 0.21; both p < 0.001). The peak SWS in the treated segment significantly decreased by 0.44 ± 0.13 (p < 0.001). The surface area of high SWS decreased from 69.97mm2 to 40.08mm2 (p = 0.002). The peak SWS in BRS group decreased to a similar extent (p = 0.775) from 0.81 ± 0.36 to 0.41 ± 0.14 (p < 0.001), compared with DES group from 0.77 ± 0.39 to 0.47 ± 0.13 (p = 0.001). Relocation of high SWS to device edges was often observed in both groups after PCI (35 of 82 cases, 41.7 %). At follow-up of BRS, the peak SWS remained unchanged compared to post-PCI (0.40 ± 0.12 versus 0.36 ± 0.09, p = 0.319). CONCLUSION: Angiography-based SWS provided valuable information about the mechanical status of coronary arteries. Device implantation led to a significant decrease of SWS to a similar extent with either polymer-based scaffolds or permanent metallic stents.

In vitro cytocompatibility and antibacterial studies on biodegradable Zn alloys supplemented by a critical assessment of direct contact cytotoxicity assay.

In vitro cytotoxicity assessment is indispensable in developing new biodegradable implant materials. Zn, which demonstrates an ideal corrosion rate between Mg- and Fe-based alloys, has been reported to have excellent in vivo biocompatibility. Therefore, modifications aimed at improving Zn's mechanical properties should not degrade its biological response. As sufficient strength, ductility and corrosion behavior required of load-bearing implants has been obtained in plastically deformed Zn-3Ag-0.5Mg, the effect of simultaneous Ag and Mg additions on in vitro cytocompatibility and antibacterial properties was studied, in relation to Zn and Zn-3Ag. Direct cell culture on samples and indirect extract-based tests showed almost no significant differences between the tested Zn-based materials. The diluted extracts of Zn, Zn-3Ag, and Zn-3Ag-0.5Mg showed no cytotoxicity toward MG-63 cells at a concentration of ≤12.5%. The cytotoxic effect was observed only at high Zn2+ ion concentrations and when in direct contact with metallic samples. The highest LD50 (lethal dose killing 50% of cells) of 13.4 mg/L of Zn2+ ions were determined for the Zn-3Ag-0.5Mg. Similar antibacterial activity against Escherichia coli and Staphylococcus aureus was observed for Zn and Zn alloys, so the effect is attributed mainly to the released Zn2+ ions exhibiting bactericidal properties. Most importantly, our experiments indicated the limitations of water-soluble tetrazolium salt-based cytotoxicity assays for direct tests on Zn-based materials. The discrepancies between the WST-8 assay and SEM observations are attributed to the interference of Zn2+ ions with tetrazolium salt, therefore favoring its transformation into formazan, giving false cell viability quantitative results.

In vitro and in vivo assessment of squeeze-cast Mg-Zn-Ca-Mn alloys for biomedical applications.

Squeeze casting of biodegradable Mg-4Zn-0.5Ca-xMn (x = 0, 0.4 or 0.8 all in weight %) alloys is a process intended to improve mechanical properties (i.e., strength and ductility), corrosion performance (i.e., resistance), and biocompatibility (i.e., little to no cytotoxicity). In this study, we found that an increased Mn content causes the dendritic microstructure of squeeze-cast Mg-4Zn-0.5Ca-xMn to become more refined and uniform, while the volume fraction of the Ca2Mg6Zn3 phase simultaneously increases. Squeeze-cast Mg-4Zn-0.5Ca-0.8Mn presents the best yield strength, ultimate tensile strength, and elongation of the alloys tested. An electrochemical corrosion test in Hanks' solution at 36.5°C demonstrates that the corrosion resistance of squeeze-cast Mg-4Zn-0.5Ca-xMn alloys show improvement at higher Mn levels. Additionally, squeeze-cast Mg-4Zn-0.5Ca alloys containing Mn exhibit favorable biocompatibility, as evidenced by cell viability studies with MC3T3-E1 cells and a local lymph node assay test. Squeeze-cast alloy specimens implanted into the skull and spine of Sprague-Dawley rats for four weeks showed no serious cytotoxicity or foreign body response; however, swelling was observed in the implantation areas of Mn-free squeeze-cast Mg-4Zn-0.5Ca alloy, while no swelling was observed in rats implanted with Mn-containing Mg-4Zn-0.5Ca alloy. These findings indicate potential applications of biodegradable, Mn-containing, squeeze-cast Mg-4Zn-0.5Ca specimens in bone-reconstruction devices given their biocompatibility, mechanical properties, and degradation profiles. STATEMENT OF SIGNIFICANCE: Bioresorbable magnesium alloys have recently gained attention as viable biomaterials for skeletal reconstruction implants. Extensive research on biodegradable Mg alloy design, synthesis, and as-cast versus post-processed material properties useful for medical applications have been reported. The squeeze-casting technique used in this study can improve the mechanical properties (i.e., strengthening) and corrosive performance (reduced rate) of bioresorbable Mg-Zn-Ca-Mn alloys. Squeeze-casting of these alloys is also expected to improve specimen microstructure, near-net-shape manufacturing, and cost (i.e., reduced). This study provides an in vitro and in vivo assessment of squeeze-cast Mg-Zn-Ca-Mn alloys for biomedical applications.

Quantitative assessment of increase in orbital volume after orbital floor fracture reconstruction using a bioabsorbable implant.

PURPOSE: To assess the postoperative changes in the orbital volume and the degree of enophthalmos after orbital floor fracture reconstruction using a bioabsorbable implant and to determine the predictors of postoperative orbital volume change. METHODS: Single-center, retrospective case series of 16 patients who underwent orbital floor fracture reconstruction using a bioabsorbable implant [poly(L-lactic acid)-poly(glycolic acid)/ß-tricalcium phosphate; Biobsorb ß®] were included. Three-dimensional volumetric calculations of orbit were determined using computed tomography scans and the degree of enophthalmos was assessed via Hertel exophthalmometry. Postoperative changes in the orbital volume and the degree of enophthalmos and their correlation were assessed. RESULTS: The mean volume of fractured orbits immediately after surgery was 22.26 ± 1.98 cm3, increasing to 23.67 ± 2.00 cm3 at 6-month follow-up (p < 0.001); the increased orbital volume was associated with postoperative deformation of the implant. The mean degree of enophthalmos was 0.09 ± 0.27 mm at 1-month follow-up, which increased to 0.66 ± 0.30 mm at 6-month follow-up (p = 0.001). Increase in orbital volume and enophthalmos progression showed a linear correlation (R = 0.682, p = 0.004). Patients with more herniated orbital tissue preoperatively showed increased postoperative orbital volume change (p = 0.015), whereas the size of the fracture area was not predictive of postoperative orbital volume change (p = 0.442). CONCLUSION: Increase in orbital volume by deformation of the bioabsorbable implant resulted in progressive enophthalmos during the postoperative follow-up period after orbital floor fracture reconstruction. Thus, careful selection of proper implants before surgery and close postoperative follow-up is needed for an optimal outcome.

Long-Term Intracoronary Structural and Vasomotor Assessment of the ABSORB Bioresorbable Vascular Scaffold.

We systematically categorized the longer-term (≥3 years) structural and functional characteristics of the ABSORB bioresorbable vascular scaffold (BVS) using optical coherence tomography imaging and coronary vasomotor reactivity testing and further compared the functional characteristics of BVS stented versus remote coronary segments. A total of 92 patients (mean age 56.4 ± 9.7 years, 22.8% women) who underwent percutaneous coronary intervention (76% with acute coronary syndrome) using the ABSORB BVS (112 lesions) were included. Optical coherence tomography analysis (38,790 visible struts) comprised in-segment quantitative lumen/plaque and semiquantitative plaque composition analysis of the neointimal pattern. Epicardial endothelium-dependent and-independent vasomotion was defined as any vasodilatation at low/intermediate intracoronary dose of acetylcholine (ACh) and nitroglycerine, assessed using quantitative coronary angiography. At a median time of 3.2 years follow-up, 79.8% of BVS segments still demonstrated visible struts with a predominant neointimal fibrotic healing pattern in 84% of BVS segments, with 99.5% of struts demonstrating coverage with apposition. Compared with remote segments, BVS segments demonstrated less endothelium-dependent vasodilatation at low (p = 0.06) and intermediate ACh doses (p = 0.04). Hypertension, longer time interval from index percutaneous coronary intervention, and the degree of in-BVS segment neointimal volume (p <0.03 for all) were each independently associated with abnormal BVS endothelium-dependent vasomotor function. Endothelium-independent function was more likely preserved in non-BVS (remote) segments compared with BVS segments (p = 0.06). In conclusion, at 3+ years post-ABSORB BVS insertion, the rate of complete scaffold resorption was low and residual strut presence was high, with a dominant fibrous healing response contributing toward neointimal hyperplasia and endothelium-dependent and-independent vasomotor dysfunction.

In vitro and in vivo degradation assessment and preventive measures of biodegradable Mg alloys for biomedical applications.

Magnesium (Mg) and its alloys have been widely explored as a potential biodegradable implant material. However, the fast degradation of Mg-based alloys under physiological environment has hindered their widespread use for implant applications till date. The present review focuses on in vitro and in vivo degradation of biodegradable Mg alloys, and preventive measures for biomedical applications. Initially, the corrosion assessment approaches to predict the degradation behavior of Mg alloys are discussed along with the measures to control rapid corrosion. Furthermore, this review attempts to explore the correlation between in vitro and in vivo corrosion behavior of different Mg alloys. It was found that the corrosion depends on experimental conditions, materials and the results of different assessment procedures hardly matches with each other. It has been demonstrated the corrosion rate of magnesium can be tailored by alloying elements, surface treatments and heat treatments. Various researches also studied different biocompatible coatings such as dicalcium phosphate dihydrate (DCPD), ß-tricalcium phosphate (ß-TCP), hydroxyapatite (HA), polycaprolactone (PCL), polylactic acid (PLA), and so on, on Mg alloys to suppress rapid degradation and examine their influence on new bone regeneration as well. This review shows the need for a standard method of corrosion assessment to predict the in vivo corrosion rate based on in vitro data, and thus reducing the in vivo experimentation.

Vasculature-on-chip for Assessment of Bioresorbable Scaffolds and Endothelial Barrier Integrity.

ABSTRACT: Endothelial cells adhere to one another through junctional structures formed by intercellular adhesion molecules. These intercellular proteins regulate barrier function in response to the hemodynamic shear rate and enable the selective passage of solutes and fluids across the endothelium. After endovascular device implantation, the endothelial barrier is compromised and becomes discontinuous, which increases permeability, allowing transmigration of leukocytes and lipoproteins and leading to the accumulation of lipid-laden foamy macrophages in the subendothelial space. Drug-coated bioresorbable vascular scaffold implants have been associated with unexpected thrombotic complications, which were not predicted in animals because of dissimilarities in endothelial regeneration and realignment between animals and humans. The development of a microengineered, microfluidics-based system of patterned channels lined with human endothelial and smooth muscle cells perfused with blood allows for the evaluation of endothelial function and barrier integrity. This review highlights the translational potential of vasculature-on-chip, which recreates the microphysiological milieu to evaluate the impact of drug-eluting bioresorbable vascular scaffolds on endothelial barrier integrity and to characterize polymer biodegradation behavior and drug release kinetic profiles over time.

Early cost estimating model for new bioabsorbable orthopedic implant candidates: A theoretical study.

An early health technology assessment (HTA) study was performed to assess the need for developing a new bioabsorbable implant for the treatment of specific orthopedic injuries. The Anterior Cruciate Ligament Reconstruction (ACLR) procedure was selected based on the need and potential impact of bioabsorbable implants in the treatment of ACL injuries. The economic model considers the possible health events after an ACLR (failures and other complications such as stiffness and pain). A decision tree approach was used, and several sensitivity analyses were performed using a Monte Carlo simulation. A cost estimating model was applied comparatively for currently available metal and bioabsorbable implants against a potential new bioabsorbable implant with improved performance. A reduction in stiffness and pain symptoms were considered as targets for these new implants performance, with reduced inflammation resulting from the use of materials with appropriate biological and mechanical properties. The current study estimates that, under the assumptions made, the introduction of a new bioabsorbable implant in ACLR surgeries may generate yearly cost savings. The model estimates positive cost-benefits of the new implant when it reduces the probability of failure by more than 30%, or reduces at least 14% the probability of complications of an inflammatory nature. The development of a new bioabsorbable orthopedic implant for ACLR is encouraged by this study identifying the need for new bioabsorbable implants with improved biological and mechanical performance. The results of this early HTA have made it possible to anticipate design needs and objectives for the research and development of new orthopedic bioabsorbable implants.

An overview of assessment tools for determination of biological Magnesium implant degradation.

Medical implants made of biodegradable materials are advantageous for short-term applications as fracture fixation and mechanical support during bone healing. After completing the healing process, the implant biodegrades without any long-term side effects nor any need for surgical removal. In particular, Magnesium (Mg) implants, while degrading, can cause physiological changes in the tissues surrounding the implant. The evaluation of structural remodeling is relevant, however, the functional assessment is crucial to provide information about physiological changes in tissues, which can be applied as an early marker during the healing process. Hence, non-invasive monitoring of structural and functional changes in the surrounding tissue during the healing process is essential, and the need for new assessing methods is emerging. This paper provides an assessment of Mg based implants, and an extensive review of the literature is presented with the focus on the imaging techniques for investigation of the Mg implants' biodegradation. The potential of a hybrid analysis, including Near-Infrared Spectroscopy (NIRS) and photoacoustic imaging (PAI) technology, is further discussed. A hybrid solution may play a significant role in monitoring implants and have several advantages for monitoring tissue oxygenation in addition to tissue's acidity, which is directly connected to the Mg implants degradation process. Such a hybrid assessment system can be a simple, ambulant, and less costly technology with the potential for clinically monitoring of Mg implants at site.

Simulated versus physical bench tests: The economic evaluation of the InSilc platform for designing, developing, and assessing vascular scaffolds.

BACKGROUND: In silico medicine allows for pre-clinical and clinical simulated assessment of medical technologies and the building of patient-specific models to support medical decisions and forecast personal health status. While there is increasing trust in the potential central role of in silico medicine, there is a need to recognize its degree of reliability and evaluate its economic impact. An in silico platform has been developed within a Horizon 2020-funded project (In-Silc) for simulations functional to designing, developing, and assessing drug-eluting bioresorbable vascular scaffolds.The main purpose of this study was to compare the costs of 2 alternative strategies: the adoption of In-Silc platform versus the performance of only physical bench tests. METHODS: A case study was provided by a medical device company. The values of the model parameters were principally set by the project partners, with use of interviews and semi-structured questionnaires, and, when not available, through literature searches or derived by statistical techniques. An economic model was built to represent the 2 scenarios. RESULTS: The InSilc strategy is superior to the adoption of physical bench tests only. Ceteris paribus, the costs are 424,355€ for the former versus 857,811€ for the latter. CONCLUSIONS: In silico medicine tools can decrease the cost of the research and development of medical devices such as bioresorbable vascular scaffolds. Further studies are needed to explore the impact of such solutions on the innovation capacity of companies and the consequent potential advantages for target patients and the healthcare system.

Splitting the Difference: Using Synthetic and Biologic Mesh to Decrease Cost in Prepectoral Immediate Implant Breast Reconstruction.

SUMMARY: Prepectoral breast reconstruction has minimized morbidity and dynamic deformities associated with submuscular implant-based breast reconstruction. However, reliance on implant coverage with acellular dermal matrix in immediate implant reconstruction remains limited by high material costs. The authors describe a technique in which anterior implant coverage in prepectoral reconstruction is split into acellular dermal matrix inferolaterally and synthetic, absorbable mesh superiorly. Use of acellular dermal matrix inferiorly provides coverage and reinforces the inframammary fold, whereas the absorbable mesh is trimmed and sutured to the acellular dermal matrix at the appropriate tension to support the implant and relieve pressure on mastectomy flaps. A retrospective review was performed on all consecutive prepectoral one-stage breast reconstructions using this technique at a single institution. Patient demographics, mastectomy and reconstruction characteristics, reconstructive outcomes, and cost of support materials were queried and analyzed. Eleven patients (21 breasts) underwent prepectoral immediate implant reconstruction with Vicryl and acellular dermal matrix anterior coverage. Average mastectomy weight was 775.8 g. Smooth, round cohesive implants were used in all cases and average implant size was 514.5 ml. Overall complication rates were low and included one minor infection (4.8 percent) and one case of minor mastectomy flap and partial nipple necrosis each (4.8 percent). Calculated cost savings of Vicryl and acellular dermal matrix anterior coverage was up to $3415 in unilateral and $6830 in bilateral cases. Prepectoral breast reconstruction using acellular dermal matrix inferiorly and Vicryl mesh superiorly is a safe technique that decreases material costs associated with support materials and allows the surgeon to precisely control the implant pocket and position. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Comparative assessment of biodegradable-antireflux heparine coated ureteral stent: animal model study.

BACKGROUND: Double J ureteral stents are widely used on urological patients to provide drainage of the upper urinary tract. Unfourtunately, ureteral stents are not free from complications, as bacterial colonization and require a second procedure for removal. The purpose of the current comparative experimental study is to evaluate a new heparin-coated biodegradable antireflux ureteral stent (BraidStent®-H) to prevent urinary bacterial colonization. METHODS: A total of 24 female pigs were underwent determination of bacteriuria and nephrosonographic, endoscopic and contrast fluoroscopy assessment of the urinary tract. Afterward, were randomly assigned animals to Group-I, in which a 5Fr double-pigtail ureteral stent was placed for 6 weeks, or Group-II, in which a BraidStent®-H was placed. Follow-up assessments were performed at 1, 3, 6, 8, 12 weeks. The final follow-up includes the above methods and an exhaustive pathological study of the urinary tract was accomplished after 20 weeks. RESULTS: Bacteriuria findings in the first 48 h were significant between groups at 6 h and 12 h. Asymptomatic bacteriuria does not reach 100% of the animals in Group-II until 48 h versus Group-I where it appears at 6 h. The weekly bacteriuria mean rate was 27.7% and 44.4% in Group I and II respectively, without statistical significance. In Group II there were no animals with vesicoureteral reflux, with statistical significance at 3 and 6 weeks with Group-I. The 91.2% of stents in Group-II were degraded between 3 and 6 weeks, without obstructive fragments. Distal ureteral peristalsis was maintained in 66.6-75% in Group-II at 1-6 weeks. CONCLUSIONS: The heparin coating of BraidStent® allows an early decrease of bacterial colonization, but its effectiveness is low at the long term. Heparin coating did not affect scheduled degradation rate or size of stents fragments. BraidStent®-H avoids the side effects associated with current ureteral stents, thus should cause less discomfort to patients.

A Multicenter Randomized Controlled Trial Comparing Safety, Efficacy, and Cost-effectiveness of the Surgisis Anal Fistula Plug Versus Surgeon's Preference for Transsphincteric Fistula-in-Ano: The FIAT Trial.

OBJECTIVE: To undertake a randomized comparison of the Biodesign Surgisis anal fistula plug against surgeon's preference in treating cryptoglandular transsphincteric fistula-in-ano. SUMMARY BACKGROUND DATA: The efficacy of the Biodesign Surgisis anal fistula plug in healing anal fistulae is uncertain. METHODS: Participants were randomized to the fistula plug with surgeon's preference (advancement flap, cutting seton, fistulotomy, Ligation of the Intersphincteric Fistula Tract procedure). The primary outcome was faecal incontinence quality of life (FIQoL) at 12-months. Secondary outcomes were fistula healing, incontinence rates, and complication and reintervention rates. RESULTS: Between May 2011 and March 2016, 304 participants were randomized to fistula plug or surgeon's preference. No differences were seen in FIQoL between the 2 groups at 12 months. Clinical fistula healing was reported in 66/122 (54%) of the fistula plug and 66/119 (55%) of the surgeon's preference groups at 12 months. Fecal incontinence rates improved marginally in both the groups. Complications and reinterventions were frequent, with significantly more complications in the fistula plug group at 6-weeks (49/142, 35% vs 25/137, 18%; P=0.002). The mean total costs were £2738 (s.d. £1151) for the fistula plug and £2308 (s.d. £1228) for the surgeon's preference group (mean difference +£430, P=0.0174). The average total quality adjusted life years (QALYs) gained was marginally higher in the fistula plug group. The fistula plug was 35% to 45% likely to be cost-effective across a willingness to pay threshold of £20,000 to £30,000 / QALY. CONCLUSIONS: The Biodesign Surgisis anal fistula plug is associated with similar FIQoL and healing rates to surgeon's preference at 12 months. Higher costs and highly uncertain gains in QALYs mean that the fistula plug may not be considered as a cost-effective treatment in the UK NHS.

In vivo assessment of biodegradable magnesium alloy ureteral stents in a pig model.

Today, ureteral stent technology is making progress towards the reduction of complications and patient discomfort. Therefore, magnesium alloys have become excellent candidate materials for manufacturing ureteral stents due to their biodegradability and antibacterial activity. Built on our previous work on biodegradable magnesium alloys, this article reports a semisolid rheo-formed magnesium implant that displays degradability and biocompatibility in vivo, and feasibility as ureteral stents in a pig model. Refined non-dendritic microstructure was observed in the rheo-formed alloy, whose grain size and shape factor were ca. 25.2 µm and ca. 1.56 respectively. Neither post-interventional inflammation nor pathological changes were observed in the urinary system during the implantation period of 14 weeks, and the degradation profile (14 weeks) meets the common requirement for the indwelling time of ureteral stents (8 to 16 weeks). Furthermore, histopathological observation and urinalysis results confirmed that the alloy had significantly higher antibacterial activity than the medical-grade stainless steel control. To our knowledge, this is the first in vivo study of biodegradable magnesium alloy as urinary implants in large animal models. Our results demonstrate that magnesium alloys may be a reasonable option for manufacturing biodegradable ureteral stents.

Cost-Effectiveness of an Antibacterial Envelope for Cardiac Implantable Electronic Device Infection Prevention in the US Healthcare System From the WRAP-IT Trial.

BACKGROUND: In the WRAP-IT trial (Worldwide Randomized Antibiotic Envelope Infection Prevention), adjunctive use of an absorbable antibacterial envelope resulted in a 40% reduction of major cardiac implantable electronic device infection without increased risk of complication in 6983 patients undergoing cardiac implantable electronic device revision, replacement, upgrade, or initial cardiac resynchronization therapy defibrillator implant. There is limited information on the cost-effectiveness of this strategy. As a prespecified objective, we evaluated antibacterial envelope cost-effectiveness compared with standard-of-care infection prevention strategies in the US healthcare system. METHODS: A decision tree model was used to compare costs and outcomes of antibacterial envelope (TYRX) use adjunctive to standard-of-care infection prevention versus standard-of-care alone over a lifelong time horizon. The analysis was performed from an integrated payer-provider network perspective. Infection rates, antibacterial envelope effectiveness, infection treatment costs and patterns, infection-related mortality, and utility estimates were obtained from the WRAP-IT trial. Life expectancy and long-term costs associated with device replacement, follow-up, and healthcare utilization were sourced from the literature. Costs and quality-adjusted life years were discounted at 3%. An upper willingness-to-pay threshold of $150 000 per quality-adjusted life year was used to determine cost-effectiveness, in alignment with the American College of Cardiology/American Heart Association practice guidelines and as supported by the World Health Organization and contemporary literature. RESULTS: The base case incremental cost-effectiveness ratio of the antibacterial envelope compared with standard-of-care was $112 603/quality-adjusted life year. The incremental cost-effectiveness ratio remained lower than the willingness-to-pay threshold in 74% of iterations in the probabilistic sensitivity analysis and was most sensitive to the following model inputs: infection-related mortality, life expectancy, and infection cost. CONCLUSIONS: The absorbable antibacterial envelope was associated with a cost-effectiveness ratio below contemporary benchmarks in the WRAP-IT patient population, suggesting that the envelope provides value for the US healthcare system by reducing the incidence of cardiac implantable electronic device infection. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02277990.

Chronic Total Occlusion 5 Years After Bioresorbable Vascular Scaffold Implantation: A Serial Optical Coherence Tomography Assessment.

Angiography at 60 months post implantation of an Absorb 1.0 bioresorbable vascular scaffold (Abbott Vascular) revealed a total occlusion at the distal scaffold. Within the proximal edge, optical coherence tomography showed complete absorption of stent struts with a decreased mean scaffold area and diameter.

Intracoronary Imaging for Assessment of Vascular Healing and Stent Follow-up in Bioresorbable Vascular Scaffolds.

Bioresorbable Vascular Scaffolds (BVS) are polymer-based materials implanted in the coronary arteries in order to treat atherosclerotic lesions, based on the concept that once the lesion has been treated, the material of the implanted stent will undergo a process of gradual resorption that will leave, in several years, the vessel wall smooth, free of any foreign material and with its vasomotion restored. However, after the first enthusiastic reports on the efficacy of BVSs, the recently published trials demonstrated disappointing results regarding long-term patency following BVS implantation, which were mainly attributed to technical deficiencies during the stenting procedure. Intracoronary imaging could play a crucial role for helping the operator to correctly implant a BVS into the coronary artery, as well as providing relevant information in the follow-up period. This review aims to summarize the role of intracoronary imaging in the follow-up of coronary stents, with a particular emphasis on the role of intravascular ultrasound and optical coherence tomography for procedural guidance during stent implantation and also for follow-up of bioabsorbable scaffolds.

Impact of bioresorbable scaffold design characteristics on local haemodynamic forces: an ex vivo assessment with computational fluid dynamics simulations.

AIMS: Bioresorbable scaffold (BRS) regions exposed to flow recirculation, low time-averaged wall shear stress (TAWSS) and high oscillatory shear index (OSI) develop increased neointima tissue. We investigated haemodynamic features in four different BRSs. METHODS AND RESULTS: Fantom (strut height [SH] = 125 µm), Fantom Encore (SH = 98 µm), Absorb (SH = 157 µm) and Magmaris (SH = 150 µm) BRSs were deployed in phantom tubes and imaged with microCT. Both 2D and 3D geometrical scaffold models were reconstructed. Computational fluid dynamics (CFD) simulation was performed to compute TAWSS and OSI. Thicker struts had larger recirculation zones and lower TAWSS in 2D. Absorb had the largest recirculation zone and the lowest TAWSS (240 µm and -0.18 Pa), followed by Magmaris (170 µm and -0.15 Pa), Fantom (140 µm and -0.14 Pa) and Fantom Encore (100 µm and -0.13 Pa). Besides strut size, stent design played a dominant role in 3D. The highest percentage area adverse TAWSS (<0.5 Pa) and OSI (>0.2) were found for Fantom (56% and 30%) and Absorb (53% and 33%), followed by Fantom Encore (30% and 25%) and Magmaris (25% and 20%). Magmaris had the smallest areas due to a small footprint and rounded struts. CONCLUSIONS: Due to stent design, both Fantom Encore and Magmaris showed smaller TAWSS and OSI than Fantom and Absorb. This study quantifies which scaffold features are most important to reduce long-term restenosis.