Polyethylene biodegradation: current status and perspectives / 生物工程学报

Polyethylene (PE) is the most abundantly used synthetic resin and one of the most resistant to degradation, and its massive accumulation in the environment has caused serious pollution. Traditional landfill, composting and incineration technologies can hardly meet the requirements of environmental protection. Biodegradation is an eco-friendly, low-cost and promising method to solve the plastic pollution problem. This review summarizes the chemical structure of PE, the species of PE degrading microorganisms, degrading enzymes and metabolic pathways. Future research is suggested to focus on the screening of high-efficiency PE degrading strains, the construction of synthetic microbial consortia, the screening and modification of degrading enzymes, so as to provide selectable pathways and theoretical references for PE biodegradation research.

Meta-analysis of different joint interfaces in total hip arthroplasty under long-term follow-up / 中国骨伤

OBJECTIVE@#To compare the long-term follow-up effect and complications of ceramic on ceramic (CoC) interface and ceramic on polyethyleneon ceramic (CoP) interface in primary total hip arthroplasty, and provide clinical evidence.@*METHODS@#Search PubMed, EMBase, the CoChrane Library databases, Web of science, Wanfang database, and CNKI from January 2000 to September 2021, screening and inclusion of randomized controlled trials (RCTs) comparing the long-term efficacy and complications of CoC interface and CoP interface in total hip arthroplasty. Literature screening, quality evaluation and data extraction were carried out according to the inclusion and exclusion criteria, using Review Manager 5.3 statistical software. The software was used to perform statistical analysis on joint function, revision, prosthesis fracture, abnormal joint noise, and prosthesis wear rate after CoC or CoP.@*RESULTS@#Seven RCTs studies were included, including 390 cases of hips with CoC artificial joints and 384 cases of hips with CoP artificial joints. The long-term joint function improvement of CoC and CoP artificial joints was similar and there was no significant differences, with an average difference was MD=0.63, 95%CI=(-1.81, 3.07), P=0.61. About the postoperative complications, CoC artificial joints have higher incidence rate of abnormal joint noise, with odds ratio (OR)=11.05, 95%CI=(2.04, 59.84), P=0.005. CoP artificial joints wear faster, with an average MD=-87.11, 95%CI=(-114.40, -59.82), P<0.000 1. There was no significant difference between the two groups in the replacement-related complications such as joint dislocation, prosthesis loosening, osteolysis, and the rate of prosthesis revision caused by various reasons.@*CONCLUSION@#The clinical function results and complications of CoC artificial joints are comparable to those of CoP artificial joints. Although CoP artificial joint prosthesis has a faster wear rate, it does not affect joint function and increase complications, and there is no abnormal joint noise. CoC is expensive and the long-term efficacy is equivalent to CoP. Clinicians should consider cost performance when choosing CoC.

Reparación primaria versus reparación y aumentación con cinta de polietileno de alto peso molecular en lesiones del ligamento cruzado anterior: resultados funcionales / Primary repair versus repair and augmentation with high molecular weight polyethylene tape in ACL injuries. Functional results

Introducción: el objetivo del trabajo es evaluar y comparar resultados funcionales en pacientes que fueron sometidos a una reparación primaria del LCA y aquellos en quienes se efectuó reparación asociada con aumentación con cinta de polietileno. Materiales y métodos: se realizó un estudio comparativo en el que se analizaron ochenta y siete pacientes intervenidos quirúrgicamente por lesión proximal del LCA entre 2017 y 2019. El grupo 1, con lesión Sherman I, fue tratado con reparación primaria (cincuenta y seis pacientes). En el grupo 2, con lesiones Sherman II, se efectuó reparación más aumentación (treinta y un pacientes). Se evaluaron el IKDC (Lysholm, Tegner, International Knee Documentation Committee), WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), y KOOS (Knee Injury and Osteoarthritis Score), preoperatorio y a los seis, doce y veinticuatro meses postoperatorios. Se consideraron significativas aquellas pruebas con p <0.001 (IC 95%). Los análisis estadísticos fueron llevados a cabo en el software estadístico R (R Core Team, 2022).Resultados: el índice de falla fue de 10.4% y 7.6% para los grupos 1 y 2, respectivamente, a los dos años del postoperatorio. Todos los scores mejoraron en el postoperatorio y fue estadísticamente significativa la diferencia con el preoperatorio a los seis y a los veinticuatro meses (p <0.001). El tipo de cirugía no tiene un efecto estadísticamente significativo en los scores clínicos. Conclusión: la reparación en una lesión proximal de LCA (Sherman I o II) es una buena alternativa quirúrgica que permite una mejoría rápida de los scores clínicos, buenos resultados y con bajo índice de complicaciones. Nivel de Evidencia: IV

Introduction: the objective of this study is to compare clinical and functional results in patients who underwent primary ACL repair and primary repair associated with augmentation with polyethylene tape. Materials and methods: eighty-seven patients who underwent surgery for proximal ACL injury between 2017 and 2019 were analyzed. The group 1, with Sherman I injury was treated with primary repair (fifty-six patients). In the group 2, with Sherman II lesions, repair plus augmentation was performed (thirty-one patients). IKDC (Lysholm, Tegner, International Knee Documentation Committee), WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), and KOOS (Knee Injury and Osteoarthritis Score) were evaluated preoperatively and at six, twelve, and twenty-four months postoperatively. Those tests with p <0.001 (95% CI) were considered significant. Statistical analyzes were carried out in the statistical software R (R Core Team, 2022). Results: the failure rate was 10.4% and 7.6% for groups 1 and 2, respectively, at two years after surgery. All the scores improved in the postoperative period, with significant difference respect to the preoperative period at six and at twenty-four months (p <0.001). Type of surgery does not have a significant effect on clinical scores.Conclusion: repairing a proximal ACL injury (Sherman I or II) is a good surgical alternative, which allows fast improvement of clinical scores, good results and a low rate of complications. Level of Evidence: IV

Clinical Evaluation of Composite Restorations with and without Polyethylene Fiber in First Permanent Molars: A 24-Month Randomized Clinical Trial

ABSTRACT Objective: To evaluate the 24-month clinical performance of composite resin restorations with and without polyethylene fiber in the first permanent molars of pediatric patients with extensive caries. Material and Methods: In total, 75 Class II restorations were placed in the permanent molar teeth of 75 children (mean age 11.3 years) with (FC; n=38) or without (C; n=37) fiber. One operator placed all the restorations. The restorations were evaluated using the modified USPHS criteria in terms of retention, color match, marginal discoloration, anatomic form, marginal adaptation, secondary caries, and postoperative sensitivity. Statistical data were analyzed using chi-square and Cochran tests (p<0.05). Results: At the end of two years, 65 restorations (FC:31; C:34) were followed up. No changes were observed during the first six months. After 24 months of follow-up, there were minor changes in marginal adaptation and marginal color in both groups; however, no statistically significant difference was observed between the clinical performances for all criteria (p>0.05). Conclusion: Extensive composite restorations with or without fibers displayed good clinical performance in high load-bearing areas after 24 months.

Effect of sealing on the feed out face of trench silos on the performance of confined calves / [Efeito da vedação na porção inicial de silos trincheiras sobre o desempenho de novilhos confinados]

This study aimed to evaluate the productive performance, dry matter intake, apparent digestibility and ingestive behavior of feedlot calves fed corn silage from the feed out face of trench silos with different types of sealing. The animals were divided into three treatments with four repetitions: Conventional seal - double-sided polyethylene of 110µm thickness; Double-sided seal - double-sided polyethylene of 200µm thickness; and Double seal - composed of double face polyethylene with a thickness of 80µm superimposed on a polyamide translucent vacuum film with a thickness of 20µm. The use of double face sealing provided 12.63% increase in average daily gain and improved food conversion by 0.62 percentage points. The apparent digestibility of the diet with double-face sealing system silage was 4.30% higher than the diet with double-face sealing silage and 11.00% higher than the diet with conventional sealing silage. It is recommended to use the double face sealing with 200µm polyethylene and double face sealing with 80µm thick polyethylene on top of a 20µm thick polyamide translucent vacuum film.(AU)

Objetivou-se avaliar o desempenho produtivo, o consumo de matéria seca, a digestibilidade aparente e o comportamento ingestivo de novilhos confinados, alimentados com silagem de milho da porção inicial de silos do tipo trincheira, conservada sob distintos tipos de vedação. Os animais foram divididos em três tratamentos, com quatro repetições: vedação convencional - polietileno tipo dupla face, com espessura de 110µm; vedação dupla face - polietileno tipo dupla face, com espessura de 200µm; e dupla vedação - polietileno tipo dupla face, com espessura de 80µm sobreposto a um filme vácuo translúcido de poliamida, com espessura de 20µm. O uso da vedação dupla face proporcionou incremento de 12,63% no ganho de peso médio diário e melhorou em 0,62 ponto percentual a conversão alimentar. A digestibilidade aparente da dieta com silagem do sistema de vedação dupla face foi 4,30% superior em relação à dieta com silagem da dupla vedação e 11,00% superior à dieta com silagem da vedação convencional. Recomenda-se a utilização tanto da vedação dupla face com polietileno de 200µm quanto da dupla vedação com polietileno tipo dupla face, com espessura de 80µm, sobreposto a um filme vácuo translúcido de poliamida com espessura de 20µm.(AU)

Contaminación por microplásticos en playas del Pacífico de Guatemala: abundancia y características / Microplastics pollution in Pacific beaches of Guatemala: abundance and characteristics

La contaminación por microplásticos (MPs) de tamaño menor a 5 mm ha tomado relevancia en los últimos años debido a su impacto en los ecosistemas. En Guatemala, se carece de información relacionada con MPs, por lo que este estudio tuvo como objetivo evaluar la abundancia y características de MPs en cuatro playas del Pacífico de Guatemala, Ocós, Tulate, Sipacate y Las Lisas. Se colectaron muestras de arena en mayo y octubre de 2019. Los MPs se aislaron y se clasificaron por forma, y el tipo de polímero se identificó a través de un equipo de espectroscopia infrarroja con transformada de Fourier (ATR-FTIR). La abundancia expresada en MPs/m2 en mayo fue de 25.6, 5.6, 0.8 y 0 MPs/m2 para Tulate, Las Lisas, Ocós y Sipacate; mientras que en octubre fue de 59.6, 23.2, 17.6 y 17.6 MPs/m2 en Tulate, Ocós, Las Lisas y Sipacate. Fragmentos, foam, pellets y láminas fueron las formas predominantes de MPs que se encontraron en las playas. El análisis por ATR-FTIR muestra que los principales polímeros identificados en las playas son polietileno, poliestireno y polipropileno. Los resultados de este estudio indican que las playas del Pacífico de Guatemala están contaminadas por MPs de diferentes tipos de polímeros. Además, estos resultados ofrecen información importante a los responsables de la toma de decisiones sobre la eliminación y el manejo de la basura plástica marina.

Microplastics < 5 mm (MPs) pollution has gained relevance in the last years because of its impact on the ecosystems. In Guatemala, information related to MPS as an environmental stressor is lacking, that is why this study aimed to assess the abundance and characteristics of MPS in four beaches to the Pacific Ocean of Guatemala, Ocós, Tulate, Sipacate, and Las Lisas. Sand samples were collected in May and October 2019. MPs were isolated and classified by shape and the type of polymer was identified by using Attenuated Total Reflec-tion-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The abundance expressed in MPs/m2 in May was 25.6, 5.6, 0.8 and 0 MPs/m2 in Tulate, Las Lisas, Ocós, and Sipacate; whereas in October was 59.6, 23.2, 17.6, and 17.6 M Ps /m2 in Tulate, Las Lisas, Ocós and Sipacate. Fragments, foam, pellets, and film were the predominant shapes found on the beaches. The ATR-FTIR analysis indicates that the main polymers identified in the beaches are polyethylene, polystyrene, and polypropylene. The results of this study indicate that the Pacific Beaches of Guatemala are contaminated by MPs of different types of polymers. These results offer important information to decision makers about disposal and management of marine plastic litter.

Comparative Biomechanical Study of Crosslinked Polyethylene Wear with 36-mm Ceramic Femoral Heads and with 32-mm Metal Femoral Heads / Estudo biomecânico comparativo do desgaste do polietileno reticulado com cabeças femorais cerâmicas de 36 mm e com cabeças metálicas de 32 mm

Abstract Objective This study aims to compare the in vitro wear rate of crosslinked, high molecular weight polyethylene coupled to 36-mm diameter ceramic heads and 32-mm diameter metal heads. Methods Ceramic-on-polyethylene (36 mm) and metal-on-polyethylene (32 mm) tribological pairs were submitted to biomechanical tests in a simulator to determine the wear rate after 15 × 106 cycles. Results A statistically significant difference (p= 0.0005) was detected when comparing the wear rate of assemblies with metallic heads (average wear: 14.12 mg/MC) and ceramic heads (average wear: 7.46 mg/MC). Conclusion The present study demonstrated the lower wear rate in prosthetic assemblies using 36-mm crosslinked ceramic-on-polyethylene tribological pairs compared to 32-mm crosslinked metal-on-polyethylene assemblies. This finding demonstrates the effectiveness of ceramic-on-polyethylene tribological pairs, even with large diameter heads.

Resumo Objetivo: O objetivo do presente estudo foi comparar, in vitro, a taxa de desgaste do polietileno de alto peso molecular reticulado acoplado a cabeças cerâmicas de 36 mm de diâmetro e acoplado a cabeças metálicas de 32 mm de diâmetro. Métodos: Foram realizados ensaios biomecânicos em simulador de desgaste para os pares tribológicos cerâmica-poli (36 mm) e metal-poli (32 mm) a fim de verificar a taxa de desgaste após em 15 × 106 ciclos. Resultados: Na comparação entre as medidas de taxa de desgaste dos conjuntos com cabeças metálicas (média:14,12 mg/MC) e cerâmicas (média:7,46 mg/MC) houve diferença estatitsticamente significativa (p= 0,0005). Conclusão: O presente estudo demonstrou menor taxa de desgaste em conjuntos protéticos que utilizaram o par tribológico cerâmica-polietileno reticulado de 36 mm em comparação aos conjuntos com metal-polietileno reticulado de 32 mm. Tal achado demonstra a eficácia do par tribológico cerâmica-poli, mesmo com a utilização de cabeças de grande diâmetro.

Pares articulares en prótesis primaria de cadera. ¿Existe alguna diferencia? / Bearing surfaces in primary hip arthroplasty. Is there any difference?

Resumen: Introducción: En un reemplazo total de cadera primario (RTC), diferentes materiales son los que se usan para las superficies de apoyo. En nuestro medio, las cabezas de metal o cerámica con polietileno altamente entrecruzado (PA) son los más utilizados. Estas combinaciones tienen buenos resultados, pero no es claro cuál es superior clínicamente. Basados en una revisión sistemática de la literatura y de los registros nacionales de artroplastía, el objetivo de este estudio es determinar si existe alguna diferencia significativa desde el punto de vista clínico. Material y métodos: Realizamos una revisión sistemática de la literatura y de los registros nacionales de artroplastía. Buscamos estudios en los que se compararan los tipos de superficie de contacto: cerámica-polietileno altamente entrecruzado (CP) y metal-polietileno altamente entrecruzado (MP), además de los registros nacionales de artroplastía que describieran, con un seguimiento mínimo de 10 años, la tasa de revisión según el tipo de superficie. El desenlace evaluado fue: tasa de revisión por cualquier causa según el tipo de superficie. Resultados: Dos de quince registros nacionales fueron incluidos: el registro australiano muestra una diferencia en la tasa de revisión a 15 años, comparando CP: 6.3 (IC 5.8, 6.7) contra MP: 5.1 (IC 4.6, 5.7). El registro de Nueva Zelanda no muestra diferencias en la tasa de revisión/100 componentes/año: CP de 0.54 (0.48-0.61) en comparación con MP de 0.61 (0.57-0.66). No encontramos estudios clínicos con los criterios de inclusión que respondan la pregunta de investigación. Conclusión: Los resultados de esta revisión muestran una alta supervivencia cuando se usa polietileno altamente entrecruzado; asimismo, los resultados son similares cuando se utilizan cabezas de cerámica o metálicas.

Abstract: Introduction: In primary hip replacement, different materials are used for bearing surfaces. In our medium metal or ceramic heads with highly crossed-linked polyethylene (PA) are the most used. These combinations have good results, but it is not clear which is clinically superior. The objective of this study is to determine whether there is any clinically significant difference based on a systematic review of the literature and national registries of arthroplasty. Material and methods: We conduct a systematic review of the literature and national registries of arthroplasty and we were looking for studies comparing bearing surfaces: ceramic-highly cross-linked polyethylene (CP) and metal-highly cross-linked polyethylene (MP); describing the revision rate according to the surface type with a minimum 10-year follow-up. The outcome evaluated was: review rate for any cause depending on surface type. Results: Two out of fifteen national registries were included. The Australian registry shows a difference in the 15-year revision rate: CP: 6.3 (IC 5.8, 6.7) vs MP: 5.1 (IC 4.6, 5.7). The New Zealand registry shows no differences in revision rate/100 components/year: CP 0.54 (0.48-0.61) vs MP 0.61 (0.57-0.66). We do not find clinical studies with inclusion criteria that answer the research question. Conclusion: The results of this review show a high survival rate with the use of highly cross-linked polyethylene, the results are similar when using ceramic or metal heads.

Influência das suplementações de ômega-3 e melatonina sobre a resposta tecidual de diferentes cimentos endodônticos / The influence of the supplementation of Omega 3 and melatonin on tissue response of different endodontic sealers

O objetivo deste estudo foi avaliar a influência das suplementações de ômega-3 e melatonina sobre a resposta tecidual de cimentos endodônticos. Foram utilizados 72 ratos Wistar alocados em 3 grupos principais: ratos controle tratados com água (TA), ratos tratados com ômega-3 (TO) e ratos tratados com melatonina (TM). Em cada rato foram implantados 4 tubos de polietileno, sendo 1 tubo vazio para controle, e os demais contendo um dos cimentos endodônticos: Sealapex®, AH Plus® e Endofil®. Os períodos de avaliação foram de 5, 15 e 30 dias (n=8/tempo). Após eutanásia, os tubos foram removidos e processados para análise microscópica. A inflamação foi avaliada em coloração de H.E. e técnica imunohistoquímica para IL-6 e TNF-α, o colágeno pela coloração de Picrosírios red e a deposição de cálcio, pela técnica de von Kossa e luz polarizada. A estatística foi realizada de acordo com cada tipo de análise, com nível de significância de 5% (p <0,05) e considerando cada tipo de suplementação comparado ao controle. Podese observar infiltrado inflamatório reduzido com o tempo e de menor intensidade nos grupos TO ou TM comparado a TA, assim como a imunomarcação para IL-6 e TNF-α. O cimento Sealapex induziu menor inflamação aos 30 dias, tanto em TO quanto em TM. Em relação ao colágeno, foi observado maior expressão de fibras imaturas no grupo TO aos 15 e 30 dias, entretanto, no grupo TM, foi observado maior quantidade de fibras maduras aos 5 dias, ambos comparados a TA. O cimento Sealapex foi único a apresentar marcação positiva para cálcio e cristais de calcita birrefringentes à luz polarizada, independente das suplementações. Pode-se concluir que a suplementação com ômega-3 ou melatonina modularam a inflamação, diminuindo o infiltrado inflamatório e a imunomarcação de IL-6 e TNF- α, estimularam o reparo tecidual e não influenciaram no processo de deposição de cálcio(AU)

The aim of this study was to evaluate the influence of omega-3 and melatonin supplements on the tissue response of endodontic sealers. 72 Wistar rats were allocated in 3 main groups: control rats treated with water (TW), rats treated with omega-3 (TO) and rats treated with melatonin (TM). In each rat, 4 polyethylene tubes were implanted, 1 empty tube for control, and the others containing one of the endodontic sealers: Sealapex®, AH Plus® and Endofil®. The evaluation periods were of 5, 15 and 30 days (n = 8 / time). After euthanasia, the tubes were removed and processed for microscopic analysis. Inflammation was evaluated in H.E. staining and immunohistochemical technique for IL-6 and TNF-α, collagen by Picrosírios red staining and calcium deposition by von Kossa and polarized light technique. Statistics were performed according to each type of analysis, with a significance level of 5% (p <0.05) and considering each type of supplementation compared to the control. It is possible to observe a reduced inflammatory infiltrate over time and less intensity in the TO or TM groups compared to TW, as well as the immunolabeling for IL-6 and TNF-α. Sealapex sealer induced less inflammation at 30 days, both in TO and TM. Regarding collagen, a greater expression of immature fibers was observed in the TO group at 15 and 30 days, however, in the TM group, a greater amount of mature fibers was observed at 5 days, both compared to TW. Sealapex sealer was the only one to present positive marking for calcium and birefringent calcite crystals under polarized light, regardless of supplementation. It can be concluded that supplementation with omega-3 or melatonin modulated the inflammation, reducing the inflammatory infiltrate and the immunolabeling of IL-6 and TNF-α, they stimulated tissue repair and did not influence the calcium deposition process(AU)

Evaluación costo-efectividad de las prótesis con superficie cerámica-polietileno vs. metal-polietileno para reemplazo articular primario de cadera en Colombia / Cost-Effectiveness of Ceramic-Polyethylene Vs Metal-Polyethylene Bearing for Primary Total Hip Replacement in Colombia

Introducción Existe una diferencia estadísticamente significativa del 1.2% en la tasa de revisión a 15 años a favor de cerámica- polietileno altamente entrecruzado (CP), demostrada en el registro nacional de artroplastia australiano. Nuestro objetivo es evaluar la costo-efectividad entre los pares: cerámica-polietileno altamente entrecruzado (CP) y metal- polietileno altamente entrecruzado (MP) para el pagador en Colombia. Materiales y métodos Se construyó un árbol de decisiones TreeAge Pro® comparando CP vs MP desde la perspectiva del Sistema de Salud Colombiano (SSC). Los parámetros se tomaron de la mejor evidencia disponible, para la efectividad se realizó una revisión sistemática de la literatura y para los costos se usaron tarifas del mercado local. Se determinó la relación de costo-efectividad incremental, asumiendo un horizonte temporal de 15 años y aplicando una tasa de descuento del 5% para costos y efectividad. La incertidumbre fue controlada por un análisis de sensibilidad determinístico y probabilístico. Resultados Para el SSC, con un umbral de 1 PIB per cápita por año de vida ganado ajustado por calidad (AVAC), en adultos llevados a RTC el uso de CP no es costo-efectiva, dado que la efectividad es similar (MP:11,32 AVAC vs CP: 11,36 AVAC) y el costo es tres veces mayor (MP $ 861.826 COP vs CP $ 2.298.090 COP). El análisis de sensibilidad determinístico demuestra que la variable más importante en el resultado es el costo de la cerámica. Discusión Para el SSC el uso rutinario de cabezas de cerámica en RTC no es una estrategia costo-efectiva.

Background There is a statistically significant difference of 1.2% in the revision rate in a 15 year follow in favour of the use of ceramic on highly cross-linked polyethylene (CP) recently described in the Australian National Joint Registry. The purpose of this study is to compare the cost-effectiveness of CP implants and metal-on-highly cross-linked polyethylene (MP) implants in patients undergoing total hip replacement (THR). Materials and methods A TreeAge Pro® decision tree was constructed in order to determine cost-effectiveness between two bearing surfaces: CP or MP from the perspective of the Colombian Health Care System (CHCS). The model parameters where taken from the best available evidence. For the effectiveness, a systematic review of the literature was performed, and costs were taken from local market rates. The incremental cost-effectiveness ratio was determined assuming a time horizon of 15 years, and a discount rate of 5% was used for costs and effectiveness. Cost-effectiveness uncertainty was controlled with deterministic and probabilistic sensitivity analysis. Results For the CHCS, with a 1PIB per capita threshold adjusted per QALY in adults undergoing (THR), the use of a CP implant is not cost-effective, given that the effectiveness is similar (11.32 QALY for MP vs 11.36 QALY for CP), and the cost is three times higher (MP $ 861.826 COP vs CP $ 2.298.090 COP). The deterministic sensitivity analysis showed that the most important variable in the results is the ceramic cost. Discussion for the CHCS the routine use of ceramic-highly cross-linked polyethylene bearing surface in a THR is not a cost-effective strategy.

Cold chain time- and temperature-controlled transport of vaccines: a simulated experimental study

Isolated Acetabular Liner Exchange for Polyethylene Wear and Osteolysis with Well-Fixed Metal Shell

BACKGROUND: The isolated liner and head exchange procedure has been an established treatment method for polyethylene wear and osteolysis when the acetabular component remains well fixed. In this study, the mid-term results of this procedure were evaluated retrospectively. METHODS: Among the consecutive patients operated on from September 1995, two patients (three hips) were excluded because of inadequate follow-up, and the results of remaining 34 patients (34 hips) were evaluated. There were 20 men and 14 women with a mean age of 49 years. A conventional polyethylene liner was used in 26 cases and a highly cross-linked polyethylene liner was used in eight cases. In three cases, the liner was cemented in a metal shell because a compatible liner could not be used. RESULTS: After a follow-up of 5 to 20.2 years, re-revision surgery was necessary in 10 cases (29.4%): in eight for wear and osteolysis at 55 to 101 months after liner exchange and in two for acetabular loosening at 1 and 1.5 years after liner exchange. Re-revision surgery included all component revision (four cases), cup revision (four cases), and liner exchange (two cases). In all re-revision cases, a conventional polyethylene liner was used initially. There was no failure in the cases in which a highly cross-linked polyethylene liner was used. CONCLUSIONS: The results of this study suggest that isolated acetabular liner exchange is a reasonable option for wear and osteolysis when the metal shell is well fixed. More promising long-term results are expected with the use of highly cross-linked polyethylene liners.

Efficacy of ramosetron in combination with polyethylene glycol of preparing for a colonoscopy / 영남의대학술지

BACKGROUND: Because of its efficacy and safety, polyethylene glycol (PEG) is generally used to prepare for colonoscopy. However, the side effects of PEG, including nausea, vomiting, abdominal discomfort, pain, and general weakness, tend to decrease patient compliance and satisfaction. The aim of this study is to investigate the efficacy and safety of PEG with 0.1 mg ramosetron on colonoscopy patients who had difficulty taking PEG due to side effects or large volume.METHODS: From January to August in 2012, 28 patients who visited Yeungnam University hospital for a colonoscopy were prospectively enrolled. All enrolled patients were previous history underwent colonoscopy using PEG only in our hospital. The efficacy and safety of ramosetron were assessed through the use of a questionnaire, and compared previous bowel preparation.RESULTS: Compared to previous examination, the patients using the ramosetron reported less nausea, vomiting, abdominal discomfort, and abdominal pain, as well as a higher degree of compliance and satisfaction of the patient. There were no side effects reported with the use of ramosetron. However, overall bowel preparation quality was not better than the previous examination.CONCLUSION: In case of the use of ramosetron in combination with PEG for bowel preparation, patients experienced a higher rate of compliance and tolerance. Looking forward, ramosetron may become an option of pretreatment for bowel preparation.

A novel technique for placing titanium mesh with porous polyethylene via the endoscopic transnasal approach into the orbit for medial orbital wall fractures

BACKGROUND: The endoscopic transnasal approach is widely used for reconstructing the medial orbital wall by filling it with a silicone sheet or Merocel, but this technique has the disadvantage of retaining the packing for a long time. To overcome this drawback, a method of positioning an absorbable plate in the orbit has been introduced, but there is a risk of defect recurrence after the plate is absorbed. Here, the authors report the results of a novel surgical technique of placing a nonabsorbable titanium mesh with porous polyethylene into the orbit through the endoscopic transnasal approach. METHODS: Fourteen patients underwent surgery using the endoscopic transnasal approach. Preoperative computed tomography (CT) was used to calculate the size of the bone defect due to the fracture, and the titanium mesh was designed to be shorter than the anteroposterior length of the defect and longer than its height. The titanium mesh was inserted into the orbit under an endoscopic view. The authors then confirmed that the titanium mesh supported the orbital contents by pressing the eyeball and finished the operation. Immediately after surgery, CT results were evaluated. RESULTS: Postoperative CT scans confirmed that the titanium mesh was well-inserted and in the correct position. All patients were discharged without any complications. CONCLUSIONS: We obtained satisfactory results by inserting a titanium mesh with porous polyethylene into the orbit via the transnasal approach endoscopically.

Reconstruction of extended orbital floor fracture using an implantation method of gamma-shaped porous polyethylene

BACKGROUND: The conventional surgical method for reconstructing orbital floor fractures involves restoration of orbital continuity by covering an onlay with a thin material under the periorbital region. However, in large orbital floor fractures, the implant after inserting is often dislocated, leading to malposition. This study aimed to propose a novel implanting method and compare it with existing methods. METHODS: Among patients who underwent surgery for large orbital floor fractures, 24 who underwent the conventional onlay implanting method were compared with 21 who underwent the novel γ implanting method that two implant sheets were stacked and bent to resemble the shape of the Greek alphabet γ. When inserting a γ-shaped implant, the posterior ledge of the orbital floor was placed between the two sheets and the bottom sheet was impacted onto the posterior wall of the maxilla to play a fixative role while the top sheet was placed above the residual orbital floor to support orbital contents. Wilcoxon signed-rank test and Mann-Whitney U test were used for data analyses. RESULTS: Compared to the conventional onlay method, the gamma method resulted in better restoration of orbital contents, better improvement of enophthalmos, and fewer revision surgeries. CONCLUSION: Achieving good surgical outcomes for extended orbital floor fractures is known to be difficult. However, better surgical outcomes could be obtained by using the novel implantation method of impacting a γ-shaped porous polyethylene posteriorly.

Hip prosthesis biomaterials: a challenge in prevention of biofilm formation / Biomateriais de próteses de quadril: um desafio na prevenção da formação de biofilme

The objective of this study was to identify the scientific evidences regarding biofilm formation prevention on hip prosthesis biomaterials. It's an integrative review that aims to answer the following question: what are the scientific evidences regarding biofilm formation prevention on hip prosthesis biomaterials? The search was performed on PubMed portal and on databases: Web of Science, Embase, Cochrane, CINAHL and LILACS. Primary studies about the topic published online up until November 2017 in English, Spanish and Portuguese are included. Among 16 primary studies, 81.25% were in vitro experimental studies, in which polyethylene showed a higher biofilm formation than metallic biomaterials and polymethylmethacrylate. Among clinical studies, Staphylococcus epidermidis and Staphylococcus aureus were isolated in most of joint prosthesis components. New acylase-containing polyurethane coatings, silver-zirconium carbonitride films, bioactive gentamicin, biodegradable gentamicin-hydroxyapatite, vancomycin, titanium-silicon-carbonoxygen-nitrogen films and cross-linked polyethylene combined with vitamin E and a poly(2-methacryloyloxyethyl phosphorylcholine) layer were developed to prevent biofilm formation. Moreover, cobalt-chromium (Co-Cr) ions inhibited bacterial growth, and cobalt-chromium particles reduced biofilm development. The biomaterials that presented properties against biofilm formation were: bioactive gentamicin, biodegradable gentamicin-hydroxyapatite, vancomycin, acylasecontaining polyurethane, cross-linked polyethylene combined with vitamin E-blended and a poly(2-methacryloyloxyethyl phosphorylcholine) layer, silver-zirconium carbonitride films and titanium-silicon-carbon-oxygen-nitrogen films. Moreover, the Co-Cr particles released from metallic joint prosthesis showed higher antibiofilm activity than Co-Cr ions.

O objetivo deste estudo foi identificar as evidências científicas a respeito da prevenção da formação de biofilme em biomateriais de próteses de quadril. Revisão integrativa da literatura, com vistas a responder a seguinte questão: quais são as evidências científicas a respeito da prevenção da formação de biofilme em biomateriais de próteses de quadril? Realizado no portal PubMed da National Library of Medicine e nas bases: Web of Science, Embase, Cochrane, CINAHL e LILACS. Incluíram-se estudos primários sobre a temática, publicados online até novembro de 2017 em inglês, espanhol e português. Dos 16 estudos primários analisados, 81,25% foram pesquisas experimentais in vitro; polietileno demonstrou maior contagem de unidades formadoras de colônia do que materiais metálicos e polimetilmetacrilato. Dos estudos clínicos, Staphylococcus epidermidis e Staphylococcus aureus foram isolados na maioria dos componentes das próteses articulares. Novos revestimentos constituídos de poliuretano contendo acilase, filmes de prata-carbonitreto de zircônio, gentamicina bioativa, gentamicina-hidroxiapatita biodegradável, vancomicina, filmes de titânio-silício-carbonooxigênio-nitrogênio e polietileno reticulado combinado com vitamina E e uma camada de poli (2-metacriloiloxietil fosforilcolina) foram desenvolvidos para prevenção da formação de biofilme. Além disso, íons de cobalto-cromo (Co-Cr) inibiram o crescimento bacteriano, e houve uma tendência das partículas de cobalto-cromo diminuírem o desenvolvimento de biofilmes. Os biomateriais que apresentaram propriedades que previnem a formação de biofilme foram: gentamicina bioativa, gentamicina-hidroxiapatita biodegradável, vancomicina, poliuretano contendo acilase, polietileno reticulado combinado com vitamina E e uma camada de poli (2-metacriloiloxietil fosforilcolina), filmes de prata-carbonitreto de zircônio e filmes de titânio-silício-carbono-oxigênio-nitrogênio. Além disso, partículas de Co-Cr liberadas das próteses articulares metálicas mostraram maior atividade antibiofilme que íons de Co-Cr.

Preoperative care of Polypoid exposed mucosal template in bladder exstrophy: the role of high-barrier plastic wraps in reducing inflammation and polyp size

ABSTRACT Objective To assess the role of high-barrier plastic wrap in reducing the number and size of polyps, as well as decreasing the inflammation and allergic reactions in exstro- phy cases, and to compare the results with the application of low-barrier wrap. Materials and Methods Eight patients with bladder exstrophy-epispadias complex (BEEC) that had used a low density polyethylene (LDPE) wrap for coverage of the exposed polypoid bladder in preoperative care management were referred. The main complaint of their parents was increase in size and number of polyps. After a period of 2 months using the same wrap and observing the increasing pattern in size of polyps, these patients were recommended to use a high-barrier wrap which is made of polyvinylidene chloride (PVdC), until closure. Patients were monitored for the number and size of polyps before and after the change of barriers. The incidence of para-exstrophy skin infection/inflammation and skin allergy were assessed. Biopsies were taken from the polyps to identify histopathological characteristics of the exposed polyps. Results The high barrier wrap was applied for a mean ± SD duration of 12±2.1 months. Polyps' size and number decreased after 12 months. No allergic reaction was detected in patients after the usage of PVdC; three patients suffered from low-grade skin allergy when LDPE was applied. Also, pre-malignant changes were observed in none of the patients in histopathological examination after the application of PVdC. Conclusion Polyps' size and number and skin allergy may significantly decrease with the use of a high-barrier wrap. Certain PVdC wraps with more integrity and less evaporative permeability may be more "exstrophy-friendly".

Cementless Total Hip Arthroplasty Using Ceramic Femoral Head on Cross-Linked Ultra-High-Molecular Weight Polyethylene Liner in Patients Older than 65 Years: Minimum Five-Year Follow-Up Results / 대한정형외과학회잡지

PURPOSE: To evaluate the utility of ceramic-on-polyethylene articular bearing surface when cementless total hip arthroplasty is performed in patients older than 65 years through an analysis of the minimum five-year follow-up results using the ceramic femoral head and cross-linked polyethylene liner. MATERIALS AND METHODS: From March 2010 to September 2012, 51 patients (56 hips) who were older than 65 years were enrolled in this retrospective study. The mean age at surgery was 70.9±5.1 years old. A clinical assessment was analyzed using the Harris hip score. For the radiographic assessment, the cup inclination and anteversion, stem alignment, and wear amount were measured. The postoperative complications were also determined. RESULTS: The mean Harris hip score was improved from preoperative 48 points to postoperative 87 points (p < 0.05). The mean cup inclination was 40.9°±6.4° and the mean cup anteversion was 20.3°±8.1°. The mean cup anteversion of the elevated liner-used group (16 cases) was 14.3°±7.9° and the mean cup anteversion of the neutral liner used group (40 cases) was 22.4°±9.1° (p < 0.05). The mean stem alignment angle was 0° (range, varus 4°–valgus 4°). The mean linear wear amount was 0.458±0.041 mm and the average annual linear wear rate was 0.079±0.032 mm/yr. Six cases (10.7%) of intraoperative periprosthetic femoral fractures were encountered. CONCLUSION: Based on these results, the use of a ceramic-on-polyethylene articular bearing surface in elderly patients with cementless total hip arthroplasty is beneficial. On the other hand, careful effort is needed to prevent intraoperative periprosthetic femoral fractures.

Salvage with Reverse Total Shoulder Arthroplasty after the Failure of Proximal Humeral Tumor Treatment / 대한정형외과학회잡지

PURPOSE: Many reconstruction methods have been attempted after an en-bloc resection of the proximal humerus. In particular, the introduction of reverse shoulder arthroplasty (RSA) has made a breakthrough in the functional recovery of the shoulder. Nevertheless, RSA has limitations when the humeral bone stock loss is significant. In addition, it is unclear if RSA is effective in patients showing failure with non-operative treatment of a proximal humeral tumor. MATERIALS AND METHODS: A reconstruction was performed using an overlapping allograft-RSA composite for 11 patients with a failed proximal humeral construct. Delayed RSA was performed on 6 patients with failed non-operative treatment. The pre- and postoperative Musculoskeletal Tumor Society (MSTS) score and the complications were addressed. RESULTS: Overlapping allograft-RSA composite afforded a stable construct in 11 failed proximal humeral reconstructions and the patient's chief complaints were resolved. The mean time to the union of overlapped allograft-host junction was 5.5 months. Average preoperative MSTS score of 20.3 point increased to 25.7 point, postoperatively. Four of the six patients who had RSA within 4 years from the index operation showed arm elevation of more than 90° whereas the remaining 5 patients showed some disability. The complications include one case each of dislocation and aseptic infection, which were resolved by changing the polyethylene liner and scar revision, respectively. None of the 6 patients who underwent delayed RSA after the failure of non-operative treatment showed arm elevation more than 90°. CONCLUSION: An overlapping allograft-RSA composite is a simple and reliable reconstructive modality in patients with massive bone loss. In patients with metastatic cancer necessitating a surgical resection at presentation, early conversion to RSA is recommended to secure functional recovery.

Mayonnaise and the Treatment of Molten Polyethylene Burns: A Case Report

Polyethylene is the most common plastic and is mainly used to produce plastic bags, film and bottles. When the molten polyethylene contacts skin,it causes burns and solidifies, so it is important to remove this material properly. However, no report has been issued to date on molten polyethylene contact burns. Here, we present such a case, in which the solidified polyethylene was successfully removed using mayonnaise. A 48-year-old man was burned on the face and neck by molten polyethylene, which had been heated to 200℃. Burned regions were covered with solidified polyethylene. About 15 minutes after spreading mayonnaise on the patient's face and neck, gently rubbing of the mayonnaise into the solidified polyethylene resulted in its successful removal. Mayonnaise has several advantages as it does not evaporate or flow across surfaces like other liquids, and unlike butter does not need to be melted before use. These properties and its ability to emulsify polythene mean that it can be used for the initial treatment of hot polyethylene burns and probably to treat contact burns caused by other petrochemical products.