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PURPOSE: To evaluate the effect of orbital wall reconstruction with absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide by assessment of the orbital volume via orbital computed tomography. METHODS: 24 patients who followed up at least 6 months after orbital wall reconstruction with unsintered hydroxyapatite/poly L-lactide were included. Retrospective clinical chart reviews for clinical manifestations and complications were performed, and orbital volume measurements were taken using the Eclipse Treatment Planning System (ver.13.0, Varian Medical System Inc., Palo Alto, CA, USA) through orbital computed tomography, which were taken before operation, right after operation, and at last follow up. RESULTS: Fourteen patients (58.3%) showed diplopia and extraocular muscle movement limitation preoperatively. Diplopia was resolved at last follow up and extraocular muscle movement limitation was improved at postoperative 6 months for all cases. The mean volumes of the fractured orbit and the unaffected orbit before operation were 23.62 ± 0.45 cm3 and 21.95 ± 1.01 cm3, respectively (p = 0.003). The mean volumes of the fractured orbit and the unaffected orbit right after operation were 21.65 ± 0.91 cm3 and 21.78 ± 0.83 cm3, respectively (p = 0.542). The mean volumes of the fractured orbit and the unaffected orbit at last follow up were 21.84 ± 0.93 cm3 and 21.81 ± 0.91 cm3, respectively (p = 0.889). CONCLUSIONS: Absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide was effective for clinical improvement and orbital volume assessment in cases of orbital wall reconstruction and it can be used safely without definite implant related complications.
Subject(s)
Humans , Absorbable Implants , Diplopia , Follow-Up Studies , Orbit , Retrospective StudiesABSTRACT
PURPOSE: To evaluate the effect of orbital wall reconstruction with absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide by assessment of the orbital volume via orbital computed tomography. METHODS: 24 patients who followed up at least 6 months after orbital wall reconstruction with unsintered hydroxyapatite/poly L-lactide were included. Retrospective clinical chart reviews for clinical manifestations and complications were performed, and orbital volume measurements were taken using the Eclipse Treatment Planning System (ver.13.0, Varian Medical System Inc., Palo Alto, CA, USA) through orbital computed tomography, which were taken before operation, right after operation, and at last follow up. RESULTS: Fourteen patients (58.3%) showed diplopia and extraocular muscle movement limitation preoperatively. Diplopia was resolved at last follow up and extraocular muscle movement limitation was improved at postoperative 6 months for all cases. The mean volumes of the fractured orbit and the unaffected orbit before operation were 23.62 ± 0.45 cm3 and 21.95 ± 1.01 cm3, respectively (p = 0.003). The mean volumes of the fractured orbit and the unaffected orbit right after operation were 21.65 ± 0.91 cm3 and 21.78 ± 0.83 cm3, respectively (p = 0.542). The mean volumes of the fractured orbit and the unaffected orbit at last follow up were 21.84 ± 0.93 cm3 and 21.81 ± 0.91 cm3, respectively (p = 0.889). CONCLUSIONS: Absorbable osteoconductive unsintered hydroxyapatite/poly L-lactide was effective for clinical improvement and orbital volume assessment in cases of orbital wall reconstruction and it can be used safely without definite implant related complications.
Subject(s)
Humans , Absorbable Implants , Diplopia , Follow-Up Studies , Orbit , Retrospective StudiesABSTRACT
BACKGROUND:Through a ful investigation of biodegradable scaffolds, we propose a new self-expanding degradable poly-L-lactide coated endotracheal stent based on the design, production, experimental and clinical applications of nickel titanium memory alloy stent. OBJECTIVE:To design a kind of biodegradable endotracheal stent with poly-L-lactide and hydroxyapatite, and to test its mechanical properties, biocompatibility and biodegradation capacity. METHODS:With the technology of computer aided design, the stents were prepared with poly-L-lactide (Mr RESULTS AND CONCLUSION:The average radial supporting force of the tracheal stent was 7.8 kPa, the percentage of stent surface coverage was less than 20%, the stent expansion rate was≥4%, and the stent longitudinal shortening rate was≤9%, which reached the mechanical requirements for degradable endotracheal stents. After 4-16 weeks, there was no significant inflammatory response. The decline in molecular weight changes and weight loss ratio was higher for in vivo degradation than in vitro degradation at different time (P<0.05). These findings indicate that poly-L-lactide/hydroxyapatite composite stents have good mechanical properties, biocompatibility and biodegradability. 150 000) and hydroxyapatite materials, 20 mm to 26 mm in diameter. The mechanical properties were tested using a universal testing machine. These poly-L-lactide/hydroxyapatite stents were implanted into dog models of tracheal stenosis at an appropriate size. The histopathological changes of the tracheas were observed, and biodegradation property was studied via molecular weight changes and weight loss ratio after 4, 8, 12, 16 weeks.
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In this study, poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(l-lactide) (PLA) microspheres containing ibuprofen were prepared with the aim of prolonging the drug release. The oil-in-water (O/W) emulsion solvent evaporation technique was used, varying the polymer ratio. All formulations provided spherical particles with drug crystals on the surface and a porous and rough polymeric matrix when PHBV was used and smooth external surface when prepared with PLA. The in vitro dissolution profiles show that the formulation containing PHBV/PLA at the proportion of 30/70 presented the best results in terms of prolonging the ibuprofen release. The analysis of the concentration of ibuprofen in the blood of rats showed that maximum levels were achieved at between one and two hours after administration of the immediate-release form (pure drug), while the prolonged microspheres led to a small amount of the drug being released within the first two hours and reached the maximum level after six hours of administration. It was concluded that it is possible to prolong the release of ibuprofen through its incorporation into PHBV/PLA microspheres.
No presente estudo foram preparadas microesferas de poli(hidroxibutirato-co-hidroxivalerato) (PHBV) e poli(ácido láctico) (PLA) com o objetivo de prolongar a liberação do ibuprofeno, utilizado como fármaco modelo. Empregou-se o método de emulsificação e evaporação do solvente óleo em água (O/A), variando-se a proporção entre os polímeros. Todas as formulações originaram partículas esféricas com cristais de fármaco aderidos à superfície externa. As microesferas apresentaram superfície rugosa e porosa, quando o PHBV foi utilizado, e superfície externa lisa, quando preparadas com o PLA. Os perfis de dissolução in vitro evidenciaram que a formulação que continha PHBV/PLA na proporção de 30/70 apresentou melhores resultados para prolongar a liberação do ibuprofeno. Através da análise da concentração de ibuprofeno no plasma de ratos, após administração oral, verificou-se que os níveis máximos ocorreram entre 1 e 2 horas após a administração de ibuprofeno não encapsulado, enquanto o fármaco presente nas microesferas atingiu um pico máximo após 6 horas da administração. Conclui-se, portanto, que é possível prolongar a liberação do ibuprofeno após a sua incorporação às microesferas preparadas com os polímeros PHBV e PLA, especialmente na proporção de 30/70.
Subject(s)
Rats , Ibuprofen/analysis , Drug Liberation , Microspheres , Polymers/analysis , In Vitro Techniques/classification , Drug LiberationABSTRACT
Objective To assess the fixation efficiency and biocompatibility of the absorbable high strength poly L lactide (SC PLLA) screws which were designed and made by us through a new material reinforcement process, solid state compression (SC), by investigating the healing and tissue reaction of the rabbits which were given femoral osteotomy and fixed with the screws. Method The right femoral condyles of 12 New Zealand rabbits were first cut off and then fixed with a SC PLLA screw. They were sacrificed at 4, 8, 12, and 36 weeks postoperatively to exam their femurs radiologically and histologically. Results At all the sites of osteotomy was seen obvious formation of bony callus. There were no significant displacements at all the operative sides. Histologically, bony union showed at the site of osteotomy and direct connection between the bone and the implants was observed. Conclusion SC PLLA screws can provide sufficient internal fixation for the load bearing cancellous bone, and possess excellent biocompatibility.
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0.05). The scaffolds produced no effect on the cell proliferation and had a low cytotoxicity, with chondrocytes tiled and lots of microspikes and matrixes secreted on the surface. Conclusion: The PCL-b-PLLA scaffold has a good compatibility with cells and is suitable for cartilage tissue engineering.
ABSTRACT
Ion irradiation is a very promising tool to modify the chemical structure and physical properities of polymers. This study was aimed to evaluate the cellular adhesion to ion beam-irradiated surface of biodegradable poly-llactide(PLLA) membrane. The PLLA membrane samples were irradiated by using 35 KeV Ar+ to fluence of 5x10(13), 5x10(14) and 5x10(15)ion/cm2. Water contact angles to control and each dose of ion beam-irradiated PLLA membranes were measured. Cultured fetal rat calvarial osteoblasts were seeded onto control and each dose of ion beam-irradiated PLLA membranes and cultured. After 24 hours, each PLLA membranes onto which osteoblasts attached were examined by scanning electron microscopy(SEM). Osteoblasts were removed from each PLLA membrane and then, the vitality and the number of cells were calibrated. Alkaline phosphatase of detached cells from each PLLA membranes were measured. Ion beam-irradiated PLLA membranes showed no significantly morphological change from control PLLA membranes. In the measurement of water contact angle to each membrane, the dose range of ion beam employed in this study reduced significantly contact angles. Among them, 5x10(14) ion/cm2 showed the least contact angle. The vitalities of osteoblastes detached from each membranes were confirmed by flow cytometer and well attached cells with their own morphology onto each membranes were observed by SEM. A very strong improvement of the cell adhesion and proliferation was observed for ion beam-irradiated surfaces of PLLA membranes. 5x10(14)ions/cm2 exhibited the most strong effect also in cellular adherence. ALPase activities also tended to increase in ion beam-irradiated membranes but statistical differences were not found. These results suggested that ion beam irradiation is an effective tool to improve the adhesion and spreading behaviour of the cells onto the biodegradable PLLA membranes for the promotion of membrane-tissue integration.