A castor oil plant (Ricinus communis)-derived implant improves the biomechanical properties of noncritical bone defects

ABSTRACT Purpose The biomechanical properties of the polyurethanes implant material derived from castor oil plant (Ricinus communis) were evaluated in a noncritical bone defect model in rat tibia. Methods After three weeks of the implant application, the tibias were tested by means of the biomechanical three-point flexion test and resistance, rigidity, energy at maximum load and maximum energy were evaluated. Nonparametric statistical analysis was performed. Results It was found that the group that received the implant behaved the same as the intact control group and also showed a significant increase in maximum load compared to the spontaneous repair group. Conclusions Our results indicate that the tibias with the implant material in a noncritical bone defect recover normal biomechanical parameters in less time than spontaneously.

Behavior study of the doped castor bean polymer rod with bioactive glass and hidroxyapatite in mice femur medullary canal

Abstract Purpose To evaluate the polymer doped rods behavior with bioactive glass and hydroxyapatite for possible application as a fracture fixing method. Methods Twenty eight Rattus norvegicus Wistar underwent bone defect for access to the femoral medullary canal and distributed into three experimental groups: group A - doped castor bean polymer with bioactive glass; group B - castor bean polymer and; group C - castor bean polymer doped with bioactive glass and hydroxyapatite. After 15 and 60 evaluation days, the femurs were removed and sent for histology and scanning electron microscopy. Results Initially mild and moderate inflammatory infiltrate is observed that decreases as time goes by, and the presence of connective tissue capsule around the graft in all groups. Regarding the biomaterials resorption little was observed. The implanted rods did not favor the osteoconductive process in the femoral medullary canal which was observed only in the C15 group. Conclusions The association of castor bean polymer, bioactive glass and hydroxyapatite was biocompatible and osteointegrable. The osteoconductive only occurred in the presence of hydroxyapatite and bioactive glass (C15 Group) and little biodegradation was observed.

Hydrocortisone release from tablets based on bioresorbable poly(ether-ester-urethane)s

Abstract Bioresorbable linear poly(ether-ester-urethane)s with different hydrophilic characteristics were synthesized from triblock copolymers of poly(ε-caprolactone)-poly(ethylene oxide)-poly(ε-caprolactone) (PCL-PEO) as macrodiols, and L-lysine diisocyanate (LDI) or hexamethylenediisocyanate (HDI) were used as the required diisocyanates. Macrodiols were obtained by ring-opening polymerization (ROP) of ε-caprolactone (CL). Polyurethanes were synthesized by the reaction of the triblock copolymers with LDI or HDI in solution using stannous 2-ethylhexanoate as catalyst. Polyurethane tablets were fabricated and investigated as prospective drug delivery systems. The effect of the PEO content on the polymers' performance as drug carriers was evaluated. It was found that water provoked more swelling and erosion of polymers with higher contents of PEO. The hydrocortisone release profiles were analyzed using the Ritger-Peppas approximation. An anomalous release behaviour (values of n higher than 0.5) was found for most of the analyzed samples.

Avaliação de custo-efetividade de dois tipos de curativos para prevenção de úlcera por pressão / Cost-effectiveness of two types of dressing for prevention of pressure ulcer

Objetivo: Analisar a relação custo-efetividade de dois tipos de curativos para a prevenção de úlcera por pressão na região sacral. Métodos : Pesquisa de análise secundária, comparativa, que incluiu 25 pacientes dos quais dez utilizaram a cobertura hidrocoloide e 15 o filme transparente, para prevenção de úlcera por pressão na região sacral. Foram contabilizados custos de aquisição com cada tipo de cobertura; verificados desfechos intermediário e final; e foi estimada a relação custo-efetividade. Resultados : A relação custo-efetividade do hidrocoloide para o desfecho intermediário foi de R$174,68 enquanto do filme transparente foi de R$45,74. Para o desfecho final, essa relação foi de respectivamente R$272,00 e R$28,97. Conclusão : O filme transparente foi mais custo-efetivo do que o hidrocoloide na prevenção de úlcera por pressão sacral.

Objective: To analyze the cost-effectiveness relationship of two types of dressing for prevention of sacral pressure ulcer. Methods : This secondary analysis and comparative study included 25 patients. Of these, 10 used a hydrocolloid dressing and 15 used a transparent film dressing for prevention of sacral pressure ulcer. We measured costs of each dressing type, verified intermediate and final results, and estimated the cost-effectiveness relationship. Results : The cost-effectiveness relationships for the intermediate results were R$174.68 for the hydrocolloid dressing and R$45.75 for the transparent film dressing. For the final result, the values were R$272.00 and R$28.97, respectively. Conclusion : For sacral pressure ulcers, transparent film dressing was cost-effective compared with hydrocolloid dressing.

Comparison of polyurethane with cyanoacrylate in hemostasis of vascular injury in guinea pigs / Comparação do poliuretano com cianoacrilato na hemostasia de injúria vascular em cobaias

Objective: To evaluate the behavior of castor oil-derived polyurethane as a hemostatic agent and tissue response after abdominal aortic injury and to compare it with 2-octyl-cyanoacrylate. Methods: Twenty-four Guinea Pigs were randomly divided into three groups of eight animals (I, II, and III). The infrarenal abdominal aorta was dissected, clamped proximally and distally to the vascular puncture site. In group I (control), hemostasis was achieved with digital pressure; in group II (polyurethane) castor oil-derived polyurethane was applied, and in group III (cyanoacrylate), 2-octyl-cyanoacrylate was used. Group II was subdivided into IIA and IIB according to the time of preparation of the hemostatic agent. Results: Mean blood loss in groups IIA, IIB and III was 0.002 grams (g), 0.008 g, and 0.170 g, with standard deviation of 0.005 g, 0.005 g, and 0.424 g, respectively (P=0.069). The drying time for cyanoacrylate averaged 81.5 seconds (s) (standard deviation: 51.5 seconds) and 126.1 s (standard deviation: 23.0 s) for polyurethane B (P=0.046). However, there was a trend (P=0.069) for cyanoacrylate to dry more slowly than polyurethane A (mean: 40.5 s; SD: 8.6 s). Furthermore, polyurethane A had a shorter drying time than polyurethane B (P=0.003), mean IIA of 40.5 s (standard deviation: 8.6 s). In group III, 100% of the animals had mild/severe fibrosis, while in group II only 12.5% showed this degree of fibrosis (P=0.001). Conclusion: Polyurethane derived from castor oil showed similar hemostatic behavior to octyl-2-cyanoacrylate. There was less perivascular tissue response with polyurethane when compared with cyanoacrylate. .

Objetivo: Avaliar o comportamento hemostático e a reação tecidual do poliuretano, derivado da mamona, após injúria da aorta abdominal de cobaias e compará-lo com o 2-octil-cianoacrilato. Métodos: Vinte e quatro cobaias foram divididas aleatoriamente em três grupos de oito animais (I, II e III). A aorta abdominal infrarrenal foi dissecada, pinçada proximal e distalmente ao local que se procedeu à punção vascular. No grupo I (controle), a hemostasia foi feita com digitopressão; no grupo II (poliuretano), aplicou-se o selante vegetal e, no grupo III (cianoacrilato), aplicou-se o 2-octil-cianoacrilato. O grupo II foi subdividido em IIA e IIB, conforme o tempo de preparo do poliuretano. Resultados: A média de perda sanguínea nos grupos IIA, IIB e III foi 0,002 g, 0,008 g e 0,170 g, com desvios padrões de 0,005 g, 0,005 g e 0,424 g, respectivamente (P=0,069). O tempo de secagem do selante cianoacrilato foi em média 81,5 segundos (s) (desvio padrão: 51,5 s), enquanto o poliuretano B levou 126,1 segundos (desvio padrão: 23,0 s) (P=0,046). Entretanto, houve tendência (P=0,069) do cianoacrilato apresentar um tempo maior de secagem que o poliuretano A. Além disso, o poliuretano A teve um tempo de secagem menor que o poliuretano B (P=0,003), com média para o IIA de 40,5 segundos (desvio padrão: 8,6 s). No grupo III, 100% dos animais tiveram fibrose moderada/acentuada, enquanto no grupo II apenas 12,5% (P=0,001). Conclusão: O poliuretano derivado da mamona apresentou comportamento hemostático semelhante ao 2-octil-cianoacrilato. A cola vegetal demonstrou menor reação tecidual perivascular. .

Polyurethane-Coated Breast Implants Revisited: A 30-Year Follow-Up

BACKGROUND: Polyurethane coating of breast implants has been shown to reduce capsular contracture in short-term follow-up studies. This 30-year study is the longest examination of the use of polyurethane-coated implants and their correlation with capsular contracture. METHODS: This study evaluates the senior surgeon's (F.D.P.) experience with the use of polyurethane-coated implants in aesthetic breast augmentation in 382 patients over 30 years. Follow-up evaluations were conducted for six months after surgery. After the six-month follow-up period, 76 patients returned for reoperation. The gross findings, histology, and associated capsular contracture were noted at the time of explantation. RESULTS: No patient during the six-month follow-up period demonstrated capsular contracture. For those who underwent reoperation for capsular contracture, Baker II/III contractures were noted nine to 10 years after surgery and Baker IV contractures were noted 12 to 21 years after surgery. None of the explanted implants had macroscopic evidence of polyurethane, which was only found during the first five years after surgery. The microscopic presence of polyurethane was noted in all capsules up to 30 years after the original operation. CONCLUSIONS: An inverse correlation was found between the amount of polyurethane coating on the implant and the occurrence of capsular contracture. Increasingly severe capsular contracture was associated with a decreased amount of polyurethane coating on the surface of the implants. No contracture occurred in patients whose implants showed incomplete biodegradation of polyurethane, as indicated by the visible presence of polyurethane coating. We recommend research to find a non-toxic, non-biodegradable synthetic material as an alternative to polyurethane.

A castor oil-containing dental luting agent: effects of cyclic loading and storage time on flexural strength

Favorable results in the use of castor oil polyurethane (COP) as pulp capping, membrane material, sealer, mouthwash and in bone repair, associated with the fact that Ricinus communis is not derived from petroleum and it is abundant in Brazil, encourage researches in the development of luting agents. Objectives This study compared the flexural strength (FS) of a castor oil-containing dental luting agent with a weight percentage of 10% (wt%) of calcium carbonate (COP10) with RelyX ARC (RX) after mechanical cycling (MC) and distilled water storage. Material and Methods Sixty-four specimens (25x2x2 mm) were fabricated and divided into two groups, COP10 and RX (control). Each group was divided into 4 subgroups (n=8) according to the storage time, 24 hours (24 h) or 60 days (60 d), and the performance (MC+FS) or not (only FS) of the mechanical cycling test. The FS (10 kN; 0.5 mm/min) and MC tests (10,000 cycles, 5 Hz, 0.5 mm/min) were carried out using an MTS-810 machine. The data were analyzed using ANOVA (α=0.05). Results The obtained FS (MPa) values were: COP10 24h- 19.04±2.41; COP10 60d- 17.92±3.54; RX 24h- 75.19±3.43; RX 60d- 88.77±6.89. All the RX specimens submitted to MC fractured, while the values for COP10 after MC were as follows: COP10 24h- 17.90±1.87 and COP10 60d- 18.60±1.60. Conclusions A castor oil-containing dental luting agent with a weight percentage of 10% (wt%) of calcium carbonate is resistant to mechanical cycling without decreases in flexural strength. However, mean COP10 showed only about 25% of the RelyX ARC mean flexural strength. .

Estudo de complicações em próteses mamárias: avaliação de 546 casos em oito anos / A report on complications of breast implantation: evaluation of 546 cases in 8 years

INTRODUÇÃO: O implante de próteses mamárias é uma das cirurgias mais frequentes e desafiadoras da cirurgia plástica, devido às complicações associadas. MÉTODO: Foi realizado um estudo retrospectivo de 546 pacientes operadas em oito anos (maio de 2004 a maio de 2012), sendo estudadas todas as pacientes submetidas à inclusão de próteses mamárias, isoladamente ou associadas à mastopexia ou mamoplastia redutora. RESULTADOS: Foram utilizadas próteses texturizadas em 84,8% e poliuretano, em 15,2%, com plano de implantação subglandular em 91,7% e submuscular, em 8,24%. Foram estudados: contratura (3,3%), seroma (2,7%), ptose (2,7%) e infecção (0,6%). A maioria das contraturas surgiu cinco anos após a cirurgia e apenas nas próteses texturizadas, que tiveram tempo de seguimento maior (4,2 anos, nas próteses texturizadas versus 1,7 ano nas de poliuretano). Houve maior frequencia de ptose nas texturizadas e de infecção, nas de poliuretano. Somente apresentaram contraturas pacientes com próteses texturizadas no período observado. Comparando-se o plano de implantação, o seroma foi mais frequente nas submusculares. Considerando-se a complexidade do procedimento, houve aumento do índice de complicações: nas implantadas com poliuretano, aumentou o índice de infecção; nas texturizadas, de ptose e seroma, mas não houve diferenças quanto à contratura. Todos os casos de infecção ocorreram em mamoplastias redutoras com próteses de poliuretano e foram causados por germes comuns, sem casos de micobactérias. CONCLUSÕES: Contraturas e ptose foram exclusivas em próteses texturizadas, no tempo de seguimento mais curto. Infecção apenas ocorreu em próteses de poliuretano. As mastopexias e mamoplastias redutoras apresentaram um índice progressivamente mais alto de complicações.

INTRODUCTION: Breast augmentation implant surgery is one of the most frequently performed plastic surgery procedures; however, it can be challenging because of its associated complications. METHOD: We conducted a retrospective study of 546 patients operated on in eight years (May 2004 to May 2012). These patients underwent breast augmentation, alone or in association with mastopexy or breast reduction. RESULTS: In this study, 84.8% textured and 15.2% polyurethane prostheses, with 91.7% deployed in the subglandular plane and 8.24% in the submuscular plane, were used. We investigated the occurrence of contracture (3.3%), seroma (2.7%), ptosis (2.7%), and infection (0.6%). Most contractures occurred 5 years after surgery and only in textured prostheses, which had a longer follow-up (4.2 years for textured implants vs. 1.7 years for polyurethane implants). There was a higher frequency of ptosis in textured implants and of infection in polyurethane implants. Only patients with textured prostheses showed contractures in the observed period. Concerning the deployment plane, seroma was more frequently observed in submuscular implants. More complex procedures showed a higher rate of complications. Polyurethane implants were associated with increased infection rates, whereas textured implants resulted in ptosis and seroma; however, there were no differences in contracture rates. All cases of infection occurred in patients who received reduction mammoplasty with polyurethane prostheses and were caused by common germs, with no cases of mycobacterial infection. CONCLUSIONS: Contractures and ptosis uniquely occurred in textured prostheses in the shortest follow-up time. Infection occurred only in polyurethane prostheses. Mastopexies and reduction mammoplasties showed a progressively higher rate of complications.

An in-vitro study to compare the force degradation of pigmented and non-pigmented elastomeric chains.

Aim: The purpose of the study was to compare the force delivery and force decay property of pigmented and non-pigmented elastomeric chains, widely used in orthodontic practice. Materials and Methods: Force delivered by the samples consisting of pigmented and non-pigmented elastomeric chains obtained from 3 manufacturers were tested at 3 time intervals (as received, after 24 hours and 21 days of stretching) to measure the force delivered by the test samples, as well as the force decay over time. Results: The force delivered by the non-pigmented samples was significantly greater than the pigmented ones at all 3 time intervals irrespective of the brand. Force decay was more significant in case of pigmented samples. Force decay was greater noticed in first 24 hours of testing and a gradual decrease in force was observed from 24 hours to 21 days in all test samples irrespective of the brand or color. Conclusion: Non-pigmented elastomeric chains exhibited better force delivery and less force decay percentage when compared to pigmented chains. Though colored elastomeric chains are widely used in present day orthodontic practice to satisfy the younger age group patients, the study ascertains the prudential use of pigmented and non-pigmented chains for efficient and faster orthodontic treatment.

Effect of implant design and bone density in primary stability

AIM: To evaluate the influence of the format and surface treatment of implants, as well as the substrate used in primary stability. METHODS: Thirty-two Conexão® implants were used: 8 conical (CC) (11.5 x 3.5 mm) and 24 cylindrical (11.5 x 3.75 mm) - 8 external hexagon implants without surface treatment (MS), 8 external hexagon implants with double Porous treatment (MP), 8 internal hexagon implants with Porous treatment (CA). They were inserted in Nacional® polyurethane in three densities (15, 20 and 40 PCF). The insertion torque (IT) (N.cm) was quantified using the digital Mackena® torque meter, and the pullout force (PF) (N) by means of axial traction force with a 200 kg load cell, performed in a Universal Test Machine (Emic® DL10000) and the Tesc 3.13 software. Data were analyzed statistically by ANOVA and Tukey's test with a significance level of 5%. RESULTS: Difference was observed between groups (p<0.05). Regarding the IT, MP and MS inserted to the substrate 40PCF showed higher values with statistically significant difference with all interactions implants x substrate; the 15 and 20PCF densities was not significant in all groups of implants. MP, MS, CC and CA did not differ significantly, even inserted in a lower density, where CC showed better IT compared with other densities. For PF, the best performance was the interaction implant CA x 40PCF substrate, showing a difference from the other implants inserted in all substrates. CONCLUSIONS: The higher bone density and cylindrical implants with surface treatment provides greater IT and PF.

In vitro evaluation of three different biomaterials as scaffolds for canine mesenchymal stem cells

PURPOSE: To evaluate in vitro ability the of three different biomaterials - purified hydroxyapatite, demineralized bone matrix and castor oil-based polyurethane - as biocompatible 3D scaffolds for canine bone marrow mesenchymal stem cell (MSC) intending bone tissue engineering. METHODS: MSCs were isolated from canine bone marrow, characterized and cultivated for seven days with the biomaterials. Cell proliferation and adhesion to the biomaterial surface were evaluated by scanning electron microscopy while differentiation into osteogenic lineage was evaluated by Alizarin Red staining and Sp7/Osterix surface antibody marker. RESULTS: The biomaterials allowed cellular growth, attachment and proliferation. Osteogenic differentiation occurred in the presence of hydroxyapatite, and matrix deposition commenced in the presence of the castor oil-based polyurethane. CONCLUSION: All the tested biomaterials may be used as mesenchymal stem cell scaffolds in cell-based orthopedic reconstructive therapy.

Prevenção de úlceras por pressão no calcanhar com filme transparente de poliuretano / Prevention's pressure ulcers heel with transparent polyurethane film

OBJETIVO: Avaliar a efetividade do filme transparente de poliuretano na prevenção de úlceras por pressão no calcâneo. MÉTODOS: Uma amostra de 100 pacientes inscritos em um ensaio controlado não-randomizado recebeu uma análise pareada de ambas as áreas do calcâneo; cada um deles recebeu a intervenção experimental (filme transparente poliuretano) no calcanhar esquerdo e a intervenção controle no calcanhar direito (somente diretrizes clínicas), constituindo um total de 200 áreas de calcanhar para análise. RESULTADOS: A incidência de úlceras por pressão foi de 32%, com 6% ocorrendo na intervenção experimental, 18% na intervenção de controle e 8% bilateralmente, com incidência significante nos primeiros 15 dias de hospitalização. A duração de tempo sem ocorrências de úlceras por pressão na intervenção experimental foi de 19,2 dias, com um intervalo de confiança de 95%. CONCLUSÃO: Foi concluído que o filme transparente de poliuretano associado às diretrizes clínicas das úlceras por pressão foi efetivo na prevenção da úlcera por pressão no calcanhar.

OBJECTIVE: Evaluate the effectiveness of transparent polyurethane film in prevention of pressure ulcer of the calcaneus. Methods: A sample of 100 patients enrolled in a non-randomized controlled trialreceived a paired analysis of both calcaneus areas; each received the experimental intervention on the left heel and the control intervention on the right heel (clinical guideline only), constituting a total of 200 heel sites for analysis. RESULTS: The incidence of pressure ulcers was 32%, with 6% occurring in the experimental intervention, 18% in the control intervention, and 8% bilaterally, with significant incidence in the first 15 days of hospitalization. The length of time without pressure ulcers occurrence with the experimental intervention was 19.2 days, with a 95% confidence interval. CONCLUSION: It was concluded that the transparent polyurethane film associated with the pressure ulcers clinical guideline was effective in the prevention of heel pressure ulcer.

Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats / Reação histopatológica sobre a superfície de próteses cobertas por espuma de silicone e poliuretano implantadas em ratos

PURPOSES: To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam. METHODS: Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III. RESULTS: There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046) when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002), with the polyurethane group displaying greater neovascularization with H&E stain. Similar results were obtained with picrosirius red, which revealed in the polyurethane group a much greater number of vessels than in the silicone group (p=0.001). The collagen area was larger in the polyurethane group, significantly at 28 days (p=0.001) and at two months (p=0.030). CONCLUSIONS: Polyurethane foam elicited more intense foreign-body reaction when compared with silicone foam. The number of vessels was higher in the capsules of the polyurethane foam implants 28 days after the operation. The capsule of the polyurethane foam implants showed a greater amount of collagen than that of the silicone foam implants.

OBJETIVOS: Avaliar, em relação ao uso de próteses, se a espuma de poliuretano apresenta maior reação de corpo estranho no organismo ao ser comparada com a espuma de silicone. Se há diferenças na vascularização das cápsulas formada ao redor das duas espumas implantadas. Se as cápsulas dos implantes de espuma de poliuretano apresentam quantidade maior de fibras colágenas ao serem comparadas com as da espuma de silicone. MÉTODOS: Utilizou-se 64 ratos albinos da linhagem Wistar, distribuídos em dois grupos de 34, grupo espuma de poliuretano e grupo espuma de silicone e receberam implantes discóides subcutâneos em seu dorso. Foram analisadas as cápsulas peri-implante com 28 dias, dois, três e seis meses após a introdução. A análise microscópica com H&E considerou as variáveis: inflamação aguda, inflamação crônica, reação de corpo estranho e neoformação vascular. A análise da coloração com picrosirius-red usando ImageProPlus considerou o número de vasos e colágeno tipo I e tipo III. RESULTADOS: Em relação à inflamação aguda e crônica, não foram encontradas diferenças estatísticas nos dois grupos. Todos os animais do grupo poliuretano, em todos os momentos, apresentaram reação de corpo estranho moderada ou intensa e foi encontrada diferença estatística significativa (p=0,046) ao serem comparados com o grupo silicone, cuja reação era ausente ou discreta aos dois meses. A neoformação vascular apresentou diferenças significativas nos dois grupos, aos 28 dias (p=0,0002); o grupo poliuretano com H&E apresentava quantidade maior de vasos neoformados e o mesmo ocorrendo com o picrosirius, cujo número de vasos era maior que no grupo silicone (p=0,001). A área de colágeno em todos os momentos foi maior no grupo poliuretano, sendo significativa com 28 dias (p=0,001) e com dois meses (p=0,030). CONCLUSÕES: A espuma de poliuretano apresentou maior reação de corpo estranho no organismo do que a espuma de silicone. A quantidade de vasos foi maior na cápsula da espuma de poliuretano com 28 dias após o implante. Aos 28 dias as cápsulas dos implantes de espuma de poliuretano apresentaram quantidade significativamente maior de colágeno do que as de espuma de silicone.

Fragmented Pigtail Percutaneous Nephrostomy Tubes: Etiology and Management

PURPOSE: To review our experience with the management of fragmented and retained pigtail percutaneous nephrostomy (PCN) tubes and to explore the reasons for the fragmentation. MATERIALS AND METHODS: We retrospectively reviewed our institute database from January 2006 to December 2011 for patients who had undergone retrieval of fragmented PCN tubes. We assessed the preoperative factors, operative technique, and post-operative outcomes. RESULTS: A total of seven patients (4 males and 3 females) had been diagnosed with fragmented PCN tubes. The mean age of the patients was 41.5 years. Of the seven patients, five required antegrade instrumentation by way of a percutaneous tract to remove the foreign body, mostly along with stone retrieval. One patient underwent ureterorenoscopy and pneumolithotripsy for a ureteric stone along with ureteroscopic removal of the PCN fragment. Another patient underwent nephrectomy of the kidney containing the PCN fragment because it had become nonfunctioning. All patients were free of stones and symptoms on follow-up. CONCLUSIONS: A prolonged waiting period for definitive surgery, urinary infection, and associated stone disease are significant factors causing fragmentation of PCN tubes. Proper insertion techniques, regular timed changes of the PCN tube, appropriate care of the PCN tube, and early surgery for underlying stone disease are required to avoid this complication. Patients with retained PCN tubes can be managed effectively with antegrade or retrograde endoscopic techniques while definitive management of the primary pathology is carried out, without any additional morbidity.

Validation of an experimental polyurethane model for biomechanical studies on implant supported prosthesis - tension tests

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, frequently hinder the development of clinical trials. The purpose of this in vitro study was to determine the modulus of elasticity of a polyurethane isotropic experimental model via tension tests, comparing the results to those reported in the literature for mandibular bone, in order to validate the use of such a model in lieu of mandibular bone in biomechanical studies. MATERIAL AND METHODS: Forty-five polyurethane test specimens were divided into 3 groups of 15 specimens each, according to the ratio (A/B) of polyurethane reagents (PU-1: 1/0.5, PU-2: 1/1, PU-3: 1/1.5). RESULTS: Tension tests were performed in each experimental group and the modulus of elasticity values found were 192.98 MPa (SD=57.20) for PU-1, 347.90 MPa (SD=109.54) for PU-2 and 304.64 MPa (SD=25.48) for PU-3. CONCLUSION: The concentration of choice for building the experimental model was 1/1.

Validation of an experimental polyurethane model for biomechanical studies on implant-supported prosthesis: compression tests

OBJECTIVES: The complexity and heterogeneity of human bone, as well as ethical issues, most always hinder the performance of clinical trials. Thus, in vitro studies become an important source of information for the understanding of biomechanical events on implant-supported prostheses, although study results cannot be considered reliable unless validation studies are conducted. The purpose of this work was to validate an artificial experimental model based on its modulus of elasticity, to simulate the performance of human bone in vivo in biomechanical studies of implant-supported prostheses. MATERIAL AND METHODS: In this study, fast-curing polyurethane (F16 polyurethane, Axson) was used to build 40 specimens that were divided into five groups. The following reagent ratios (part A/part B) were used: Group A (0.5/1.0), Group B (0.8/1.0), Group C (1.0/1.0), Group D (1.2/1.0), and Group E (1.5/1.0). A universal testing machine (Kratos model K - 2000 MP) was used to measure modulus of elasticity values by compression. RESULTS: Mean modulus of elasticity values were: Group A - 389.72 MPa, Group B - 529.19 MPa, Group C - 571.11 MPa, Group D - 470.35 MPa, Group E - 437.36 MPa. CONCLUSION: The best mechanical characteristics and modulus of elasticity value comparable to that of human trabecular bone were obtained when A/B ratio was 1:1.

A Case of Parapharyngeal Foreign Bodies Causing Explosion of Polyurethane Foam in Oral Cavity / 대한이비인후과학회지

Foreign bodies in the upper digestive tract are frequently encountered accidental cases in otolaryngologic fields. Oropharyngeal foreign bodies consisting of polyurethane foam have never been reported. Moreover, foreign bodies penetrating into the parapharyngeal space of neck are rare but when it does, it may also cause extensive neurovascular injuries. Polyurethanes are widely used in manufacturing industries but serious hazards of these materials have not been reported. In this article, we report a man who, presented with foreign bodies that entered as a result of an explosion of polyurethane foam in the oral cavity. The foreign body had entered into the parapharyngeal space, very close to the vertebral artery.

Implante de ducto nasolacrimal de poliuretano: relato de caso / Nasolacrimal stent implantation: report of a case

Obstrução parcial ou completa da via lacrimal provoca um lacrimejamento constante ou intermitente denominado epífora. O tratamento preconizado para os casos de epífora com obstruções localizadas abaixo do canalículo comum é a dacriocistorrinostomia externa ou a dacriocistorrinostomia via endoscópica. Nos últimos anos foram criadas e aperfeiçoadas técnicas alternativas para o tratamento de epífora como a intubação da via lacrimal com tubos de silicone, dilatação do ducto nasolacrimal (dacriocistoplastia) e o desenvolvimento de implantes nasolacrimais. O objetivo deste trabalho é relatar a primeira experiência brasileira com o implante de poliuretano, realizado pelos serviços de Radiologia Intervencionista e Oftalmologia do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo - USP - SP. Embora o implante nasolacrimal tenha suas vantagens por ser um procedimento radiológico intervencionista versus uma cirurgia invasiva, não é o procedimento indicado como tratamento primário da obstrução do ducto nasolacrimal. Estudos a longo prazo ainda são necessários para avaliar e resolver as complicações encontradas nos últimos trabalhos. Novos desenhos e métodos de recanalização in situ (mecanicamente ou com auxílio de medicações) talvez melhorem a viabilidade deste método terapêutico para a resolução de epífora.

Epiphora (watering eye) is generally caused by insufficient drainage of tears. The most common cause of epiphora in adults is idiopathic inflammatory obstruction of the nasolacrimal duct. The traditional surgical treatment of nasolacrimal duct obstruction is an external dacryocystorhinostomy, which has an 85 percent to 95 percent success rate. To eliminate cutaneus wounds and scarring some techniques were introduced, for example the endonasal laser dacryocystorhinostomy and the nasolacrimal stent. The aim of this report was to evaluate the first case of nasolacrimal stent implantation in Brazil. The procedure was performed in the "Hospital das Clínicas" of the University of São Paulo - USP. A female patient with tearing of the right eye and secretion was submitted to a nasolacrimal stent implantation, with fluoroscopic guidance. The stent used in this procedure was the polyurethane Tearleader stent set. (Dr. Wilhelm type-PBN MEDICALS - Denmark). After 3 months, the patient started complaining of tearing, so the stent was removed and the patient was submitted to an external dacryocystorhinostomy. At present the patient does not have any symptoms or complaints. This procedure is less invasive and simple, causes no facial scars and avoids surgical trauma, but the long term success rates achieved using polyurethane nasolacrimal stents are low as compared with the external dacryocystorhinostomy. In addition, the patients usually complaint of tearing even having patent lacrimal system. In summary, long-term studies are needed to resolve some complications. Maybe a new stent design and new methods of unblocking the stent in situ would improve in the near future the levels of patency that currently are modest.

Polyurethane Semi-occlusive Dressing for Full Thickness Skin Graft Application

A traditional tie-over dressing may be applied to support the take of a skin graft. Although there are many advantage of this method, it has significant disadvantages, including time-consuming application. Furthermore, when the dressing is changed, the gauze becomes hard and can be stuck to the graft, causing damage and pain upon removal. The purpose of our study is to evaluate the effect of semi-occlusive dressing using polyurethane foam and film dressing(Allevyn(R), Opsite(R)) after full thickness skin graft. The authors treated 45 cases including burn scar contracture(n=38), syndactyly (n=1), absence of nipple-areolar complex(n=4), traumatic skin defect(n=1) and contact burn(n=1) with authors' method and 39 patients including burn scar contracture (n=39) with the tie-over dressing between 2000 and 2004. The patients in polyurethane foam and film dressing group ranged from 1 to 62 years of age (mean age, 15.1 years) and the patients in tie-over dressing group ranged from 2 to 60 years of age(mean age, 21.3 years). The postoperative results were analyzed according to the following measures: (1) the duration of graft-taking, (2) the admission period, (3) complications. Compared with the traditional tie-over dressing, polyurethane foam and film dressing was shown to be more successful in a reduced duration of graft-taking, in which was similar to the former in the rate of graft-taking, a reduced admission period and patient's discomfort. We concluded that semi-occlusive dressing using Allevyn(R) and Opsite(R) was an effective method after full thickness skin graft, which was easy to shape to difficult body locations, such as web spaces, fingers and maintains a moist environment for wound healing and does not stick to the wound.

Shape-memory polymers for medical equipment applications / 医疗卫生装备

Shape-memory polymers(SMPs) can retain a temporary shape after pre-deformation at an elevated temperature and subsequent cooling to a lower temperature.When reheated,the original shape can be recovered.The development of the research on polyolefin,polyurethanes,polyester and some other shape-memory polymers were introduced and their applications in medical equipment were reviewed.