Bone Incorporation of a Poly (L-Lactide-Co-D, L-Lactide) Internal Fixation Device in a Rat's Tibia: Microtomographic, Confocal LASER, and Histomorphometric Analysis.

This study evaluated the bone incorporation process of a screw-shaped internal fixation device made of poly (L-lactide-co-D, L-lactide) (PLDLLA). Thirty-two male Wistar rats received 32 fixation devices (2 mm × 6 mm) randomly assigned to either the right or left tibia and one implant in each animal. After 7, 14, 28, and 42 days, the rats were euthanized and the specimens were subjected to microtomographic computed tomography (microCT) and histomorphometric analyses to evaluate bone interface contact (BIC%) and new bone formation (NBF%) in cortical and cancellous bone areas. The animals euthanized on days 28 and 42 were treated with calcein and alizarin red, and confocal LASER microscopy was performed to determine the mineral apposition rate (MAR). Micro-CT revealed a higher percentage of bone volume (p < 0.006), trabecular separation (p < 0.001), and BIC in the cortical (p < 0.001) and cancellous (p = 0.003) areas at 28 and 42 days than at 7 and 14 days. The cortical NBF at 42 days was greater than that at 7 and 14 days (p = 0.022). No statistically significant differences were observed in cancellous NBF or MAR at 28 and 42 days. Based on these results, it can be seen that the PLDLLA internal fixation device is biocompatible and allows new bone formation around the screw thread.

The Incorporation of Zinc into Hydroxyapatite and Its Influence on the Cellular Response to Biomaterials: A Systematic Review.

Zinc is known for its role in enhancing bone metabolism, cell proliferation, and tissue regeneration. Several studies proposed the incorporation of zinc into hydroxyapatite (HA) to produce biomaterials (ZnHA) that stimulate and accelerate bone healing. This systematic review aimed to understand the physicochemical characteristics of zinc-doped HA-based biomaterials and the evidence of their biological effects on osteoblastic cells. A comprehensive literature search was conducted from 2022 to 2024, covering all years of publications, in three databases (Web of Science, PUBMED, Scopus), retrieving 609 entries, with 36 articles included in the analysis according to the selection criteria. The selected studies provided data on the material's physicochemical properties, the methods of zinc incorporation, and the biological effects of ZnHA on bone cells. The production of ZnHA typically involves the wet chemical synthesis of HA and ZnHA precursors, followed by deposition on substrates using processes such as liquid precursor plasma spraying (LPPS). Characterization techniques confirmed the successful incorporation of zinc into the HA lattice. The findings indicated that zinc incorporation into HA at low concentrations is non-cytotoxic and beneficial for bone cells. ZnHA was found to stimulate cell proliferation, adhesion, and the production of osteogenic factors, thereby promoting in vitro mineralization. However, the optimal zinc concentration for the desired effects varied across studies, making it challenging to establish a standardized concentration. ZnHA materials are biocompatible and enhance osteoblast proliferation and differentiation. However, the mechanisms of zinc release and the ideal concentrations for optimal tissue regeneration require further investigation. Standardizing these parameters is essential for the effective clinical application of ZnHA.

Evaluation of the degradation of two bioabsorbable interference screws: an in-vivo study in sheep

Purpose: To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + ß-tri-calcium phosphate (ß-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery. Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/ß-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions: The inclusion of ß-TCP favors screw degradation since the PDLLA/ß-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/ß-TCP screws presented less bone tissue at the implantation site.

A tomada de decisão no uso de sistema de fixação absorvível em cirurgias bucomaxilofaciais: revisão sistemática / Decision making in the use of absorbable fixation system in maxillofacial surgery: a systematic review / Toma de decisiones en el uso de sistemas de fijación absorbibles en cirugías maxilofaciales: revisión sistemática

Introdução: As fraturas ósseas faciais são muito comuns em lesões de face, destacando-se as fraturas mandibulares. Para o tratamento delas é necessário haver um sistema de fixação a fim de restaurar o osso fraturado, sua forma e função. Objetivo: Identificar fatores influenciadores do uso de sistemas de fixação absorvíveis em cirurgias buco maxilo faciais. Material e método: Trata-se de uma revisão sistemática feita nas bases de dados MEDLINE, BBO e SciELO, no período de agosto de 2019 a setembro de 2020 nos portais da PubMed e BVS. Dentre os 322 achados e após utilização de filtros, leitura de títulos e resumos, foram incluídos 30 artigos para compor a revisão. Resultados: Os achados do estudo revelam existir uma série de fatores influenciáveis na escolha do melhor material, tais como: sua aplicação em pacientes pediátricos ou adultos, a palpabilidade das placas, a resistência, as principais medidas de satisfação, o envolvimento com doenças malignas, complicações e novidades que a literatura vem discutindo sobre o tipo de material. Conclusão: O uso de placas absorvíveis é aconselhado para uso pediátrico, pois minimizam as restrições ao crescimento, dispensam a necessidade de uma cirurgia secundária, reduzindo, assim, gastos hospitalares. Além disso, as placas biodegradáveis originam exames de imagem com menos artefatos, de modo que não comprometem diagnósticos em pacientes com neoplasias(AU)

Introduction: Facial bone fractures are very common in facial injuries, highlighting mandibular fractures. In order to treat them, it is necessary to have a fixation system in order to restore the fractured bone, its shape and function. Objective: To identify factors influencing the use of absorbable fixation systems in oral maxillofacial surgery. Material and method: This is a systematic review carried out in the MEDLINE, BBO and SciELO databases, from August 2019 to September 2020 in the portals of PubMed and VHL. Among the 322 findings and after using filters, reading titles and abstracts, 30 articles were included to compose the review. Results: The findings of the study reveal that there are a number of influential factors in the choice of the best material, such as: its application in pediatric or adult patients, the palpability of the plates, the resistance, the main measures of satisfaction, the involvement with malignant diseases, complications andthe main novelties that the literature has been discussing about the type of material. Conclusion: The use of absorbable plates is advised for pediatric use, because they minimize the restrictions to growth, dispense the need for a secondary surgery, thusreducing hospital expenses. Besides that, the biodegradable plates originate imaging exams with fewer artifacts, so that it does not compromise the diagnosis of patients with cancer(AU)

Introducción: Las fracturas de los huesos faciales son muy frecuentes en las lesiones faciales, especialmente las fracturas mandibulares. Para poder tratarlos es necesario disponer de un sistema de fijación con el fin de restaurar el hueso fracturado, su forma y función. Objetivo: Identificar los factores que influyen en el uso de sistemas de fijación absorbible en cirugía oral maxilofacial. Material y método: Se trata de una revisión sistemática realizada en las bases de datos MEDLINE, BBO y SciELO, de agosto de 2019 a septiembre de 2020 en los portales de PubMed y VHL. Entre los 322 hallazgos y luego de utilizar filtros, leer títulos y resúmenes, se incluyeron 30 artículos para componer la revisión. Resultados: Los hallazgos del estudio revelanque existen una serie de factores que influyen en la elección del mejor material, tales como: su aplicación en pacientes pediátricos o adultos, la palpabilidad de las placas, la resistencia, las principales medidas de satisfacción, la implicación con enfermedades malignas, complicaciones y las principales novedades que ha venido discutiendo la literatura sobre el tipo de material. Conclusión: Se recomienda el uso de placas absorbibles para uso pediátrico, ya que minimizan las restricciones de crecimiento, prescinden de la necesidad de cirugía secundaria, reduciendo así los gastos hospitalarios. Además, las placas biodegradables dan como resultado pruebas de imagen con menos artefactos, de modo que no comprometen el diagnóstico em pacientes con neoplasias(AU)

Delay of neuropathic pain sensitization after application of dexamethasone-loaded implant in sciatic nerve-injured rats

Neuroimmune interactions underlying the development of pain sensitization in models of neuropathic pain have been widely studied. In this study, we evaluated the development of allodynia and its reduction associated with peripheral antineuroinflammatory effects induced by a dexamethasone-loaded biodegradable implant. Chronic constriction injury (CCI) of the sciatic nerve was performed in Wistar rats. The electronic von Frey test was applied to assess mechanical allodynia. The dexamethasone-loaded implant was placed perineurally at the moment of CCI or 12 days after surgery. Dorsal root ganglia (DRG; L4-L5) were harvested and nuclear extracts were assayed by Western blot for detection of nuclear factor (NF)-κB p65/RelA translocation. Dexamethasone delivered from the implant delayed the development of allodynia for approximately three weeks in CCI rats when the implantation was performed at day 0, but allodynia was not reversed when the implantation was performed at day 12. NF-κB was activated in CCI rat DRG compared with naïve or sham animals (day 15), and dexamethasone implant inhibited p65/RelA translocation in CCI rats compared with control. This study demonstrated that the dexamethasone-loaded implant suppresses allodynia development and peripheral neuroinflammation. This device can reduce the potential side effects associated with oral anti-inflammatory drugs.

Aligned ovine diaphragmatic myoblasts overexpressing human connexin-43 seeded on poly (L-lactic acid) scaffolds for potential use in cardiac regeneration.

Diaphragmatic myoblasts (DMs) are precursors of type-1 muscle cells displaying high exhaustion threshold on account that they contract and relax 20 times/min over a lifespan, making them potentially useful in cardiac regeneration strategies. Besides, it has been shown that biomaterials for stem cell delivery improve cell retention and viability in the target organ. In the present study, we aimed at developing a novel approach based on the use of poly (L-lactic acid) (PLLA) scaffolds seeded with DMs overexpressing connexin-43 (cx43), a gap junction protein that promotes inter-cell connectivity. DMs isolated from ovine diaphragm biopsies were characterized by immunohistochemistry and ability to differentiate into myotubes (MTs) and transduced with a lentiviral vector encoding cx43. After confirming cx43 expression (RT-qPCR and Western blot) and its effect on inter-cell connectivity (fluorescence recovery after photobleaching), DMs were grown on fiber-aligned or random PLLA scaffolds. DMs were successfully isolated and characterized. Cx43 mRNA and protein were overexpressed and favored inter-cell connectivity. Alignment of the scaffold fibers not only aligned but also elongated the cells, increasing the contact surface between them. This novel approach is feasible and combines the advantages of bioresorbable scaffolds as delivery method and a cell type that on account of its features may be suitable for cardiac regeneration. Future studies on animal models of myocardial infarction are needed to establish its usefulness on scar reduction and cardiac function.

Long-Term Follow-Up of Patients after Percutaneous Coronary Intervention with Everolimus-Eluting Bioresorbable Vascular Scaffold / Seguimento Muito Tardio de Pacientes após Intervenção Coronária Percutânea com Suporte Vascular Bioabsorvível Eluidor de Everolimus

Abstract Background: Bioresorbable vascular scaffolds (BVS) were developed to improve the long-term results of percutaneous coronary intervention, restoring vasomotion. Objectives: To report very late follow-up of everolimus-eluting Absorb BVS (Abbott Vascular, Santa Clara, USA) in our center. Methods: Observational retrospective study, in a single Brazilian center, from August 2011 to October 2013, including 49 patients submitted to Absorb BVS implantation. Safety and efficacy outcomes were analyzed in the in-hospital and very late follow-up phases (> 2 years). Results: All 49 patients underwent a minimum follow-up of 2.5 years and a maximum of 4.6 years. Mean age was 56.8 ± 7.6 years, 71.4% of the patients were men, and 26.5% were diabetic. Regarding clinical presentation, the majority (94%) had stable angina or silent ischemia. Device success was achieved in 100% of cases with 96% overall procedure success rate. Major adverse cardiovascular events rate was 4% at 30 days, 8.2% at 1 year, and 12.2% at 2 years, and there were no more events until 4.6 years. There were 2 cases of thrombosis (1 subacute and 1 late). Conclusions: In this preliminary analysis, Absorb BVS showed to be a safe and effective device in the very late follow-up. Establishing the efficacy and safety profiles of these devices in more complex scenarios is necessary.

Resumo Fundamento: Os suportes vasculares bioabsorvíveis (SVB) foram desenvolvidos com o intuito de melhorar os resultados da intervenção coronária percutânea a longo prazo, restabelecendo-se a vasomotricidade. Objetivos: Reportar o seguimento muito tardio do implante do SVB eluidor de everolimus Absorb® (Abbot Vascular, Santa Clara, EUA) em nosso centro. Métodos: Estudo observacional, retrospectivo, em um único centro brasileiro, que incluiu 49 pacientes submetidos ao implante do SVB Absorb® entre agosto/2011 e outubro/2013. Foram analisados os desfechos de segurança e eficácia na fase hospitalar e bastante tardia (> 2 anos). Resultados: Todos os 49 pacientes completaram um seguimento mínimo de 2,5 anos, sendo o máximo de 4,6 anos. A média de idade foi 56,8 ± 7,6 anos, sendo 71,4% da população estudada do sexo masculino e 26,5% composta por diabéticos. Considerando a apresentação clínica, a grande maioria (94%) tinha angina estável ou isquemia silenciosa. Obteve-se sucesso do dispositivo em 100% dos casos e do procedimento, em 96%. A taxa de eventos cardiovasculares maiores foi de 4% aos 30 dias, de 8,2% em 1 ano, e de 12,2% em 2 anos, sem mais eventos até 4,6 anos. Houve 2 casos de trombose (1 subaguda e 1 tardia) até o último seguimento. Conclusões: Nesta análise preliminar, o uso do SVB Absorb® mostrou-se seguro e eficaz no seguimento bastante tardio. Faz-se necessário estabelecer o perfil de eficácia e segurança destes dispositivos em cenários de maior complexidade.

Bone healing after biodegradable mini-plate fixation

PURPOSE:To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits.METHODS:Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared.RESULTS:Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months.CONCLUSION:The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.(AU)

Bone healing after biodegradable mini-plate fixation

ABSTRACT PURPOSE: To compare bone healing in mandibular vertical body osteotomies (MVBO) after fixation with a resorbable 2.0mm-profile fixation system in the first and third postoperative months in rabbits. METHODS: Twenty hemimandibles of ten rabbits were divided into two groups according to duration of resorbable fixation-one or three months. The MVBOs were performed and one four-hole, resorbable, 2.0mm mini-plate fixation system was used on each side. The computed tomography (CT) scans, scanning electron microscopy (SEM), and histomorphometric outcomes of groups I and II were compared. RESULTS: Significant differences were found between the one- and three- month assessments in terms of newly formed bone ratio values (p<0.05). There was more new bone formation at the third month on both the CT and histomorphometric examinations. A better adaptation of the bone tissues to the resorbable mini-plate and screws was observed on SEM at three months. CONCLUSION: The resorbable mini-plates provided a fixation stable enough to allow immediate oral alimentation and callus formation in both groups.

Estudo comparativo entre osteossíntese em fratura de tornozelo com implantes convencionais e bioabsorvíveis / Comparative study between osteosynthesis in conventional and bioabsorbable implants in ankle fractures

Objetivo: Comparar os resultados funcionais de fraturas de tornozelo tratadascom placas metálicas e absorvíveis. Métodos: Vinte pacientes foramrandomizados e seguidos de forma prospectiva em dois grupos, metálicoe absorvível. No período pós-operatório imediato os pacientes foram imobilizadoscom tala gessada por uma semana, que foi substituída por órteseremovível por quatro semanas adicionais. Carga parcial foi autorizada comtrês semanas, e carga total com seis semanas. Os vinte pacientes foramseguidos por nove meses e avaliados funcionalmente aos seis e nove meses.Resultados: A recuperação funcional foi similar nos dois grupos. Aosseis meses, três pacientes no grupo metálico queixaram-se de problemaslocais, e tiveram seus implantes removidos. Um paciente do grupo absorvívelteve uma deiscência precoce da sutura, submetida a desbridamentoe sutura com boa evolução. Aos seis e nove meses o escore da AmericanOrthopaedic Foot and Ankle Society (AOFAS) foi aplicado para todosexceto um paciente do grupo metálico, que foi perdido do seguimento.Os resultados funcionais foram semelhantes nos dois grupos, nos doismomentos. Conclusão: Os implantes absorvíveis permitiram resultadosclínicos e funcionais semelhantes aos metálicos em fraturas de tornozelo.Nível de Evidência II, Estudo Prospectivo Comparativo.

Objective: To compare the functional results of ankle fracturestreated with metallic and absorbable plates. Twentypatients were randomized into two groups (metallic and absorbableimplant groups) and followed prospectively. In theimmediate postoperative period, patients were immobilizedwith plaster casts for one week, which was replaced by aremovable cast for another four weeks. Partial weight-bearingwas allowed after three weeks, and full weight-bearing aftersix weeks. Functional recovery was similar in both groups. Atsix months, three patients in the metallic group complainedof local pain, and had their implants removed. One patientin the absorbable group exhibited early dehiscence of thesuture and underwent debridement and suturing with goodevolution. The American Orthopaedic Foot and Ankle Society(AOFAS) score was similar between the two groups after sixand nine months of follow-up. The absorbable implants showedclinical and functional results that were similar to thoseof metallic implants. Level of Evidence II, ProspectiveComparative Study.

COMPARATIVE STUDY BETWEEN OSTEOSYNTHESIS IN CONVENTIONAL AND BIOABSORBABLE IMPLANTS IN ANKLE FRACTURES.

OBJECTIVE: To compare the functional results of ankle fractures treated with metallic and absorbable plates. Twenty patients were randomized into two groups (metallic and absorbable implant groups) and followed prospectively. In the immediate postoperative period, patients were immobilized with plaster casts for one week, which was replaced by a removable cast for another four weeks. Partial weight-bearing was allowed after three weeks, and full weight-bearing after six weeks. Functional recovery was similar in both groups. At six months, three patients in the metallic group complained of local pain, and had their implants removed. One patient in the absorbable group exhibited early dehiscence of the suture and underwent debridement and suturing with good evolution. The American Orthopaedic Foot and Ankle Society (AOFAS) score was similar between the two groups after six and nine months of follow-up. The absorbable implants showed clinical and functional results that were similar to those of metallic implants. Level of Evidence II, Prospective Comparative Study.

Dissecções de Borda Após Implante Coronário de Suportes Vasculares Biorreabsorvíveis. Análise Seriada com Tomografia de Coerência Óptica / Edge Dissections After the Coronary Implantation of Bioresorbable Scaffolds. Serial Analysis Using Optical Coherence Tomography

Introdução: A incidência de dissecções de borda, após o implante de suportes vasculares biorreabsorvíveis (SVBs), ainda não foi investigada. Esses suportes têm hastes mais espessas e requerem pré-dilatação mais agressiva no implante. Avaliamos a incidência de dissecções de borda após implante de SVBs, seus aspectos morfométricos e o processo de cicatrização, com imagens de tomografia de coerência óptica (OCT) seriadas. Métodos: Incluímos pacientes consecutivos, que foram tratados com SVBs polimérico, e que possuíam avaliação com OCT após o procedimento e aos 6 meses de evolução. Dissecções de borda foram definidas como rupturas da superfície luminal nos 5 mm distais ou proximais ao SVB. Resultados: Das 96 bordas de 48 SVB implantados em 48 lesões de 48 pacientes, 91 bordas estavam disponíveis para a análise. Dissecções foram detectadas pela OCT em 28 bordas (30,7%) de 22 lesões (45,8%), com igual distribuição entre as bordas distais e proximais. Todas as dissecções apareceram como flaps e não foram visualizadas pela angiografia. Doença aterosclerótica esteve presente em 96,4% das bordas dissecadas; a maioria era fibrocalcificada (40,8%) e mais de um terço era rica em lipídio. O comprimento médio das dissecções foi 1,80 mm e a área média dos flaps tinha 0,30 mm. A maioria ...

Background: The incidence of edge dissections after the coronary implantation of bioresorbable scaffolds (BRS) has not been investigated. BRS have thicker struts and require more aggressive pre-dilation for implantation. The incidence of edge dissections after BRS implantation, their morphological aspects and healing process were evaluated using serial optical coherence tomography (OCT) images. Methods: Consecutive patients treated with a polymeric BRS, who had an OCT evaluation after the procedure and at 6-month follow-up, were included in the current analysis. Edge dissections were defined as luminal surface ruptures, 5-mm distally or proximally to the BRS edges. Results: Out of 96 edges from 48 BRS implanted in 48 lesions of 48 patients, 91 edges were available for analysis. Dissections were detected by OCT in 28 edges (30.7%) and in 22 lesions (45.8%), with equal distribution between distal and proximal edges. All dissections appeared as flaps and none were visible by angiography. Atherosclerotic disease was present in 96.4% of all dissected edges; most were fibrocalcific (40.8%), and more than one-third were lipid-rich. Mean dissection length was 1.80 mm, and the mean flap area was 0.30 mm. Most dissections (89.3%) were superficial and restricted to the intima/atheroma layer. At the 6-month follow-up 92.8% of all dissections healed completely, and there was no significant reduction in the luminal dimensions at the edge segments, with only one case of restenosis. ...

Modificações na angulação coronária após implante de suporte vascular bioabsorvível e de stents de cromo-cobalto e aço inoxidável / Changes in coronary angulation after bioresorbable vascular scaffold and cobalt-chromium and stainless steel stent implantation

INTRODUÇÃO: A conformabilidade do stent, definida como a adaptação da prótese à forma natural do vaso, é a principal responsável pelas alterações geométricas produzidas após o implante do dispositivo, sendo influenciada pelo material e pelo desenho do stent. Ela pode ser aferida medindo-se as modificações da curvatura e a angulação do segmento tratado após o implante do stent. O objetivo deste estudo foi comparar as mudanças na angulação coronária após implante do suporte vascular bioabsorvível (SVB) e das plataformas metálicas de cromo-cobalto e aço inoxidável, utilizadas em stents farmacológicos de segunda geração. MÉTODOS: Foram incluídos, nesta análise retrospectiva, 50 pacientes com lesões únicas, de novo, em coronárias nativas, com diâmetro entre 2,5 e 3,5 mm e extensão de até 23 mm. Vinte e cinco pacientes foram tratados com SVB e 25 pacientes com plataformas metálicas de cromo-cobalto (n = 12) ou de aço inoxidável (n = 13). A angulação foi medida usando um software de angiografia coronária quantitativa dedicado. RESULTADOS: A angulação do vaso modificou-se significativamente após o implante dos dispositivos. No grupo submetido ao implante de plataformas metálicas, houve maior modificação do ângulo coronário quando comparado ao tratado com SVB (41,6% vs. 14,9%; P < 0,01). Quando observado o comportamento do SVB e das diferentes plataformas metálicas, a alteração do ângulo coronário foi maior para as plataformas de aço inoxidável, seguida das plataformas de cromo-cobalto e os SVB (53,7% vs. 28,5% vs. 14,9%; P < 0,01). CONCLUSÕES: Nesta avaliação preliminar, o SVB produziu uma menor mudança da angulação coronária. O impacto clínico deste achado necessita ser investigado prospectivamente em uma coorte maior e mais complexa.

BACKGROUND: The conformability of the stent, defined as the adaptation of the prosthesis to the natural shape of the vessel, is the major cause of geometrical changes after stenting and is influenced by the stent material and design. It may be assessed by measuring changes in the curvature and the angulation of the treated segment after stent implantation. The objective of this study was to compare changes in coronary angulation after implantation of the bioresorbable vascular scaffold (BVS) and cobalt-chromium and stainless steel metal platforms used in second-generation drug-eluting stents. METHODS: In this retrospective analysis, 50 patients with single de novo lesions in native coronary arteries and diameter between 2.5 and 3.5 mm and length up to 23 mm were included. Twenty-five patients were treated with BVS and 25 patients were treated with cobalt-chromium (n = 12) or stainless steel (n = 13) platforms. Angulation was measured using a dedicated quantitative angiography analysis software. RESULTS: Vessel angulation significantly changed after device implantation. In the group submitted to the implantation of metal platforms there was greater coronary angulation change when compared to the group treated with BVS (41.6% vs. 14.9%; P < 0.01). When we analyzed the performance of the BVS and the different metal platforms, coronary angulation change was greater for the stainless steel platforms, followed by cobalt-chromium platforms and the BVS (53.7% vs. 28.5% vs. 14.9%; P < 0.01). CONCLUSIONS: In this preliminary assessment, the BVS produced a smaller coronary angulation change. The clinical impact of this finding must be prospectively investigated in a larger and more complex cohort.

Comparação da retração aguda do stent entre o suporte vascular bioabsorvível eluidor de everolimus e dois diferentes stents metálicos farmacológicos / Comparison of acute stent recoil between the everolimus-eluting bioresorbable vascular scaffold and two different drug-eluting metallic stents

INTRODUÇÃO: Suportes vasculares bioabsorvíveis (SVB) têm sido desenvolvidos como forma de fornecer sustentação à parede do vaso enquanto ocorre o processo de cicatrização, após a intervenção coronária percutânea (ICP), sendo absorvido posteriormente. Pelo fato da plataforma ser de material polimérico, existe preocupação em relação à retração aguda do dispositivo. Avaliamos aqui a retração aguda do SVB com a de dois diferentes stents farmacológicos metálicos. MÉTODOS: Foram incluídos 50 pacientes com lesões não complexas. Dentre esses pacientes, 25 foram tratados com SVB e comparados a outros 25 pacientes tratados com stent de cromo-cobalto eluidor de everolimus (EES; n = 12) ou stent de aço inoxidável eluidor de biolimus (BES; n = 13). A retração aguda foi definida como a diferença entre o diâmetro médio do balão durante a pressão máxima de inflação (X) e o diâmetro médio do stent após o esvaziamento do balão (Y). A porcentagem de retração aguda foi definida como (X - Y)/X. RESULTADOS: Não houve diferença significativa em relação às características clínicas e angiográficas basais. O ganho luminal agudo foi menor com o SVB comparado ao EES e ao BES (1,51 ± 0,41 mm vs. 1,76 ± 0,28 mm vs. 1,9 ± 0,42 mm; P = 0,02). A retração aguda foi de 0,21 ± 0,13 mm vs. 0,15 ± 0,08 mm vs. 0,14 ± 0,08 mm (P = 0,21), e o porcentual de retração aguda foi de 7,0 ± 4,6% vs. 5,0 ± 2,2% vs. 5,7 ± 4,1% (P = 0,16). CONCLUSÕES: O SVB demonstrou ter retração aguda ligeiramente maior, embora não significativa, que os stents metálicos farmacológicos de segunda geração.

BACKGROUND: Bioresorbable vascular scaffolds (BVS) have been developed to provide support to the vessel wall during the healing process after percutaneous coronary intervention (PCI), being reabsorbed afterwards. Because the scaffold is made of polymeric material, there is a concern regarding the acute recoil of the device. We compared the BVS acute recoil with that of two different metallic drug-eluting stents. METHODS: Fifty patients with non-complex lesions were included. Twenty-five of these patients were treated with a BVS who were compared to 25 patients treated with a cobalt-chromium everolimus-eluting stent (EES, n = 12) or a stainless steel biolimus-eluting stent (BES, n = 13). Acute recoil was defined as the difference between the mean diameter of the balloon during maximum inflation pressure (X) and the mean diameter of the stent immediately after balloon deflation (Y). The percentage of acute recoil was defined as (X-Y)/X. RESULTS: There was no significant difference in the baseline clinical and angiographic characteristics. Acute luminal gain was lower with BVS compared to EES and BES (1.51 ± 0.41 mm vs. 1.76 ± 0.28 mm vs. 1.9 ± 0.42 mm, P = 0.02). Acute recoil was 0.21 ± 0.13 mm vs. 0.15 ± 0.08 mm vs. 0.14 ± 0.08 mm (P = 0.21) and the percentage of acute recoil was 7.0 ± 4.6% vs. 5.0 ± 2.2% vs. 5.7 ± 4.1% (P = 0.16). CONCLUSIONS: BVS presented a slightly higher, although not significant, acute recoil than the two second-generation metallic drug-eluting stents.

Membrana do biopolímero da cana-de-açúcar: avaliação experimental na orelha média / Sugarcane biopolymer membrane: experimental evaluation in the middle ear

O desenvolvimento dos biomateriais é importante na cirurgia. O comportamento de uma nova membrana derivada da cana-de-açúcar será avaliado na orelha média do rato. OBJETIVOS: Analisar a interação da membrana do biopolímero da cana-de-açúcar na mucosa da orelha do rato. MATERIAL E MÉTODO: Estudo experimental, prospectivo e pareado com 24 ratos Wistar. A membrana do biopolímero da cana-de-açúcar foi inoculada na orelha média direita e a fáscia autóloga na orelha esquerda. Os ratos foram subdivididos em 3 grupos de 8 e sacrificados com 4, 8 e 12 semanas após a cirurgia. Foi realizada uma análise histológica da mucosa da orelha média e da membrana timpânica. RESULTADOS: Houve reação inflamatória no grupo experimental com exsudato subagudo em 50 por cento dos casos e 30 por cento exsudato crônico; 20 por cento estava normal. A inflamação foi intensa inicialmente, mas diminuiu no decorrer do tempo. No grupo controle houve apenas um caso de exsudato. Miringoesclerose na membrana timpânica foi observada em ambos os grupos. A biomembrana foi absorvida tardiamente em comparação com a fáscia. CONCLUSÕES: A membrana do biopolímero da cana-de-açúcar causou reação inflamatória na orelha média, com regressão no tempo tardio do experimento e fibrose leve. Futuros estudos podem direcionar seu uso na otorrinolaringologia.

New developments on biomaterials are important in surgery. The behavior of a new membrane produced from sugarcane will be evaluated in the middle ear of rats. AIM: This study analyzed the results from the interaction of the sugarcane-base biopolymer membrane in the middle ear of a rat. MATERIALS AND METHODS: We ran an experimental, prospective, paired study with 24 Wistar rats. The sugarcane-base polymer membrane was inoculated in the right ear; and an autologous fascia in the left ear. The rats were divided in 3 groups of 8, and slaughtered at 4, 8 and 12 weeks after surgery. Histological analyses were performed on the rats' middle ear mucosa and their tympanic membranes. RESULTS: There was an inflammatory reaction on the experimental group and middle ear subacute exudate in 50 percentof the cases; 30 percent chronic exudate; and 20 percent was normal. In the control group there was only one case of exudate. The inflammation was initially described as intense, but it decreased over time. Myringosclerosis was observed in both groups. The sugarcane biopolymer membrane was absorbed later when compared with fascia. CONCLUSION: The sugarcane biopolymer membrane induced an inflammatory reaction in the middle ear which decreased over time, and mild fibrosis. Future studies can indicate its use in otolaryngology.

Sistemas biodegradáveis contendo acetato de prednisolona para administração orbitária / Biodegradable systems containing prednisolone acetate for orbital administration

OBJETIVO: O presente estudo objetivou o desenvolvimento e a avaliação de um sistema biodegradável de liberação de fármacos com característica de liberação prolongada, destinado à administração orbitária de acetato de prednisolona (AP). MÉTODOS: O sistema desenvolvido, na forma de microesferas (MEs) de poli-e-caprolactona (PCL) contendo o AP, foi obtido pelo método de evaporação de solvente. As MEs foram caracterizadas por microscopia eletrônica de varredura (MEV), calorimetria diferencial exploratória (DSC), avaliação do teor de encapsulação e pelo perfil de liberação in vitro. O perfil de liberação in vivo foi avaliado em coelhos após administração peribulbar de uma suspensão aquosa das MEs. A biocompatibilidade local do sistema foi verificada por meio de análise histopatológica da região de implantação. RESULTADOS: Após obtenção das MEs, a análise morfológica por MEV mostrou a viabilidade do método de obtenção do sistema. O teor de AP encapsulado foi de 43 ± 7 por cento e pode ser considerado bastante satisfatório. A caracterização do sistema por DSC, além de confirmar a sua estabilidade, não indicou a existência de interação entre o fármaco e o polímero. O estudo de liberação in vitro indicou que o sistema apresenta perfil de liberação prolongada. O estudo in vivo confirmou o perfil de liberação prolongado do AP a partir das MEs, sugerindo, também, a viabilidade do sistema devido à ausência de toxicidade local. CONCLUSÃO: O conjunto dos resultados obtidos neste trabalho é relevante e credencia o sistema desenvolvido como uma possível alternativa ao tratamento de orbitopatias inflamatórias.

PURPOSE: The present study aimed to evaluate an injectable extended-release formulation of prednisolone acetate (PA) for orbital administration. METHODS: Microspheres (MEs) of poly-e-caprolactone (PCL) containing PA were developed by the method of solvent evaporation. The MEs obtained were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), encapsulation efficiency and in vitro release profile. The in vivo release profile was evaluated in rabbits after periocular injection of an aqueous suspension of MEs. The local biocompatibility of the system was verified by histopathologic analysis of the deployment region. RESULTS: After MEs preparation, morphological analysis by SEM showed the feasibility of the employed method. The content of PA encapsulated was 43 ± 7 percent and can be considered as satisfactory. The system characterization by DSC technique, in addition to confirm the system stability, did not indicate the existence of interaction between the drug and the polymer. The in vitro release study showed the prolonged-release features of the developed system. Preliminary in vivo study showed the absence of local toxicity and confirmed the prolonged release profile of PA from MEs, suggesting the viability of the developed system for the treatment of orbital inflammatory diseases. CONCLUSION: The results obtained in this work are relevant and accredit the system developed as a possible alternative to the treatment of inflammatory orbitopathy.

Nova tecnologia: valvuloplastias com anéis biodegradáveis / New technology: valve repair using biodegradable rings

OBJETIVO: Introduzir um novo conceito na tecnologia de anuloplastia. Embora anéis rígidos e flexíveis cumpram com as necessidades básicas em adultos, não preservam mudanças na forma e no tamanho ocorridos durante o ciclo cardíaco. Se implantado em crianças, eles não permitem o crescimento do anel nativo. Métodos: De março de 2003 a março de 2007, 207 pacientes submeteram-se ao reparo da valva mitral e/ou tricúspide implantando anéis biodegradáveis de polidioxanona Bioring®. Pacientes foram separados em dois grupos: Grupo 1, Adultos n=121. Idade média: 48 anos (± 19,2). Mais velho 85 anos. Grupo 2, Pediátrico: n=86. Idade média: 9,6 anos (± 4,4). Mais novo 0,5 anos. RESULTADOS: Grupo 1 - mortalidade hospitalar: 3,3 por cento; seguimento médio: 26,4 meses ± 15,4. Quatro pacientes submetidos à substituição da valva mitral 1,2,2 e 4 meses pós-reparo. Grupo 2 - mortalidade hospitalar: 1,2 por cento; seguimento médio: 26,7 meses, ± 13,4. Sete reoperações mitrais entre 1 a 24 meses, duas para novo reparo da válvula, cinco para substituição valvar. CONCLUSÕES: Anéis biodegradáveis remodelam a forma, reforçam o reparo, devolvem a função das valvas atrioventriculares, mantendo a dinâmica tridimensional e geometria dos anéis valvares mitrais e tricuspídeos. Além disso, estes anéis preservam o crescimento potencial em crianças. Embora o anel de anuloplastia biodegradável tenha sido inicialmente desenvolvido para população pediátrica, é atualmente aplicado em adultos. Crianças com ventrículoúnico e incompetências valvares A-V são indicações adicionais. Resultados a médio prazo mostraram que a degradação do produto ocorreu sem conseqüências negativas observáveis. Resultados a longo termo deverão comprovar estes achados.

OBJECTIVE: To introduce a new concept in the annuloplasty technology. Although rigid and flexible rings meet the basic needs of adults, they do not preserve the changes in shape and size occurring during the cardiac cycle. If implanted in children, such materials do not allow growth of the native annulus. METHODS: From March 2003 to March 2007, 207 patients underwent mitral and/or tricuspid valve repair implanting polidioxanone biodegradable rings - Bioring®. Patients were divided into two groups: Group 1, Adults: n=121. Mean age: 48 years (± 19.2). Oldest 85 years. Group 2, Pediatric: n=86. Mean age: 9.6 years (± 4.4). Youngest 0.5 years. RESULTS: Group 1, Hospital mortality: 3.3 percent. Mean follow-up: 26.4 months ± 15.4. Four patients underwent mitral valve replacement 1, 2, 2 and 4 months post repair. Group 2, Hospital mortality: 1.2 percent. Mean follow-up: 26.7 months±13.4. Seven mitral reoperations within 1 to 24 months, two for valve re-repair, five for valve replacement. CONCLUSIONS: Biodegradable rings remodel the shape, reinforce the repair, restore the function of the atrioventricular valves and maintain the three dimensional dynamic motion and geometry of the mitral and tricuspid valves annulus. Growth potential is preserved in children. Although the biodegradable annuloplasty ring was first designed and developed for a pediatric population, it is currently applied to adult cases. Children with single ventricle and AV valve incompetence are an additional indication. The mid-term results showed that degradation of the device occurred without negative observable consequences. Long-term results should confirm these findings.

Treatment of mandibular fracture bybio-absorbable fixation: case report / Tratamento de fratura de mandíbula através de material reabsorvível: relato de caso

Among the fracture in oral and maxillofacial trauma compound, the one in lower third occupy prominent place due to its frequency and immediate esthetic and functional damage. Several techniques and materials are used for its treatment, for example, the titanium screws and plates and, more recently, a bio-absorbable system in which, once intalled the plate and screws, it will be degraded by the organism. The present work describes a clinical case of a facial trauma with consequent mandible fracture in a female patient aging 39 years old. Once reduced the fracture, the stabilization was accomplished by the bio-absorbable system. There was not any rejection to the material and the patient developed satisfactorily after the treatment.

Fixação interna de fragmento osteocondral originado de osteocondrite dissecante do joelho / Internal fixation of osteochondral fragment originated fro dissecting knee osteochondritis

O tratamento da osteocondrite dissecante do joelho com lesão tipo cratera associada a corpo livre intra-articular pode ser realizado pela fixação do fragmento osteocondral no seu local de origem. No entanto, existem controvérsias quanto à indicação e eficácia deste procedimento, principalmente quando o corpo livre está solto por tempo prolongado, já que existem relatos na literatura demonstrando deterioração do revestimento condral do mesmo diretamente relacionado com o intervalo decorrente de sua soltura. Relatamos um caso em que, apesar do fragmento osteocondral estar livre na articulação por aproximadamente cinco semanas, a sua fixação não trouxe complicações e resultou em cicatrização completa da lesão. Nós concluímos que, principalmente nos casos onde a lesão osteocondral no côndilo femoral envolve a superfície de carga, quando então o descarte do fragmento geralmente resultaria em mau prognóstico, as possíveis complicações da fixação tardia são compensadas pelos benefícios obtidos pela redução do fragmento osteocondral no local de origem, resultando na recuperação da congruência articular e possivelmente evitando um processo degenerativo articular precoce.

The treatment of dissecting knee osteochondritis with crater-like lesion associated to intra-articular loose body can be provided by fixating the osteochondral fragment on its original site. However, there is some concern about the efficacy of this approach, since some reports have shown that the cartilage layer in osteochondral loose bodies that have been detached for a long time becomes deteriorated. We report a case where while the osteochondral loose body was detached for as long as five weeks, the fixation to the osteochondral defect was uneventful and resulted in a completely healed lesion. We concluded that, especially in cases in which the lesion involves a weight-bearing area of the knee with a detached osteochondral fragment, when the prognosis is usually worse if the fragment is discarded, potential complications of the fixation are offset by the benefits achieved by reducing the osteochondral fragment at the crater-like lesion, resulting in better joint congruence, and potentially avoiding an early joint degeneration process.