Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 6 Articles
Background: Staphylococcus epidermidis (S. epidermidis) has emerged as one of the leading pathogens of\nbiomaterial-related infections. Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial molecule\ncontrolling extravasation of leukocytes. Sialic acid-binding immunoglobulin-like lectin 9 (Siglec-9) is a leukocyte ligand\nof VAP-1. We hypothesized that 68Ga-labeled 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-conjugated\nSiglec-9 motif containing peptide (68Ga-DOTA-Siglec-9) could detect inflammatory response due to S. epidermidis\nperi-implant infection by positron emission tomography (PET).\nMethods: Thirty Sprague-Dawley rats were randomized into three groups. A sterile catheter was implanted into\nthe medullary canal of the left tibia. In groups 1 and 2, the implantation was followed by peri-implant injection of\nS. epidermidis or Staphylococcus aureus (S. aureus) with adjunct injections of aqueous sodium morrhuate. In group 3,\nsterile saline was injected instead of bacteria and no aqueous sodium morrhuate was used. At 2 weeks after operation,\n68Ga-DOTA-Siglec-9 PET coupled with computed tomography (CT) was performed with the measurement of the\nstandardized uptake value (SUV). The presence of the implant-related infection was verified by microbiological\nanalysis, imaging with fluorescence microscope, and histology. The in vivo PET results were verified by ex vivo\nmeasurements by gamma counter.\nResults: In group 3, the tibias with implanted sterile catheters showed an increased local uptake of 68Ga-DOTA-Siglec-9\ncompared with the intact contralateral bones (SUVratio +29.5%). 68Ga-DOTA-Siglec-9 PET detected inflammation induced\nby S. epidermidis and S. aureus catheter-related bone infections (SUVratio +58.1% and +41.7%, respectively). The tracer\nuptake was significantly higher in the S. epidermidis group than in group 3 without bacterial inoculation, but the\ndifference between S. epidermidis and S. aureus groups was not statistically significant. The difference between\nthe S. aureus group and group 3 was neither statistically significant.\nConclusion: PET/CT imaging with novel 68Ga-DOTA-Siglec-9 tracer was able to detect inflammatory tissue\nresponse induced by catheter implantation and staphylococcal infections....
Background: The purpose of the present study was to assess the value for money achieved by bar-retained implant\noverdentures based on six implants compared with four implants as treatment alternatives for the edentulous maxilla.\nMethods: A Markov decision tree model was constructed and populated with parameter estimates for implant and\ndenture failure as well as patient-centred health outcomes as available from recent literature. The decision scenario was\nmodelled within a ten year time horizon and relied on cost reimbursement regulations of the German health care\nsystem. The cost-effectiveness threshold was identified above which the six-implant solution is preferable over the\nfour-implant solution. Uncertainties regarding input parameters were incorporated via one-way and probabilistic\nsensitivity analysis based on Monte-Carlo simulation.\nResults: Within a base case scenario of average treatment complexity, the cost-effectiveness threshold was identified\nto be 17,564 ââ??¬ per year of denture satisfaction gained above of which the alternative with six implants is preferable over\ntreatment including four implants. Sensitivity analysis yielded that, depending on the specification of model input\nparameters such as patientsââ?¬â?¢ denture satisfaction, the respective cost-effectiveness threshold varies substantially.\nConclusions: The results of the present study suggest that bar-retained maxillary overdentures based on six implants\nprovide better patient satisfaction than bar-retained overdentures based on four implants but are considerably more\nexpensive. Final judgements about value for money require more comprehensive clinical evidence including\npatient-centred health outcomes....
Background: The purpose of this study was to evaluate surgical healing rates, implant failure, implant removal, and\nthe need for surgical revision with regards to plate type in midshaft clavicle fractures fixed with 2.7-mm\nanteroinferior plates utilizing modern plating techniques.\nMethods: This retrospective exploratory cohort review took place at a level I teaching trauma center and a single\nlarge private practice office. A total of 155 skeletally mature individuals with 156 midshaft clavicle fractures between\nMarch 2002 and March 2012 were included in the final results. Fractures were identified by mechanism of injury\nand classified based on OTA/AO criteria. All fractures were fixed with 2.7-mm anteroinferior plates. Primary outcome\nmeasurements included implant failure, malunion, nonunion, and implant removal. Secondary outcome\nmeasurements included pain with the visual analog scale and range of motion. Statistically significant testing was\nset at 0.05, and testing was performed using chi-square, Fisherââ?¬â?¢s exact, Mannââ?¬â??Whitney U, and Kruskall-Wallis.\nResults: Implant failure occurred more often in reconstruction plates as compared to dynamic compression plates\n(p = 0.029). Malunions and nonunions occurred more often in fractures fixed with reconstruction plates as\ncompared to dynamic compression plates, but it was not statistically significant. Implant removal attributed to\nirritation or implant prominence was observed in 14 patients. Statistically significant levels of pain were seen in\npatients requiring implant removal (p = 0.001) but were not associated with the plate type.\nConclusions: Anteroinferior clavicular fracture fixation with 2.7-mm dynamic compression plates results in excellent\nhealing rates with low removal rates in accordance with the published literature. Given higher rates of failure,\n2.7-mm reconstruction plates should be discouraged in comparison to stiffer and more reliable 2.7-mm dynamic\ncompression plates....
Background: The long term radiological status of screw fixation following scoliosis surgery with all pedicle screw\nconstruct is not previously studied.\nAim: To evaluate the incidence of loosening (implant failure) evaluated with low-dose CT two years following scoliosis\nsurgery.\nStudy design: Retrospective study.\nMethods: 81 consecutive patients with adolescent idiopathic scoliosis (AIS), aged 18 Ã?± 3 years at 2 years follow-up\n(83% were female), subjected for scoliosis corrective surgery with all pedicle screw construct (total of 1666 screws) has\nbeen examined with plain radiography and with low dose CT 6 weeks and 2 years postoperatively.\nResults: In 26 out of 81 (32%) patients there were signs of loosening of one or more screws, a maximum 3 screws.\n47 out of 1666 (2.8%) screws showed evidence of loosening. Preoperative Cobb angle was 56Ã?° among patients with\nloosening compared with 53Ã?° among patients with no evidence of loosening (P = 0.288). In males there were signs of\nloosening in 8 out of 14 (57%) and in females 18 out of 67 (27%), (P = 0.027). Among cases with loosening, 14% had\nsuboptimal screw placement at the first postoperative CT compared with 11% among patients with no evidence of\nloosening (P = 0.254). One patient with a loosened L4 screw had neurological deficit and subjected for revision of the\nconstruct. Out of 26 patients with evidence of loosening, 5 patients reported minor pain or discomfort, 1 patient had a\nminor proximal junctional kyphosis of about 15Ã?° and 3 patients showed evidence of pull-out of 3ââ?¬â??5 mm at the upper\nend of the construct but no clinical complaint. With plain radiography loosening could be observed only in 11 out of\n26 cases, 5 were in the lumbar region.\nConclusions: In a consecutive series of 81 cases with AIS who had underwent scoliosis surgery, one third showed,\n2 years after the intervention, minor screw loosening. Males were more prone to develop screw loosening. In CT\nsystem that enables low-dose protocol, CT is recommended for the evaluation of evidence of screw loosening....
Background: Local slow release implant provided long term and stable drug release\nin the lesion. The objective of this study was to fabricate biodegradable slow release\nINH/PLLA tablet via 3 dimensional printing technique (3DP) and to compare the\ndrug release characteristics of three different structured tablets in vitro.\nMethods: Three different drug delivery systems (columnar-shaped tablet (CST),\ndoughnut-shaped tablet (DST) and multilayer doughnut-shaped tablet (MDST)) were\nmanufactured by the three dimensional printing machine and isoniazid was loaded\ninto the implant. Dynamic soaking method was used to study the drug release\ncharacteristics of the three implants. MTT cytotoxicity test and direct contact test\nwere utilized to study the biocompatibility of the implant. The microstructures of the\nimplantsââ?¬â?¢ surfaces were observed with electron microscope.\nResults: The PLLA powder in the tablet could be excellently combined through 3DP\nwithout disintegration. Electron microscope observations showed that INH\ndistributed evenly on the surface of the tablet in a ââ?¬Å?nest-shapedââ?¬Â way, while the\nsurface of the barrier layer in the multilayer doughnut shaped tablet was compact\nand did not contain INH. The concentration of INH in all of the three tablets were\nstill higher than the effective bacteriostasis concentration (Isoniazid: 0.025 ~ 0.05 ?g/\nml) after 30 dayââ?¬â?¢s release in vitro. All of the tablets showed initial burst release of the\nINH in the early period. Drug concentration of MDST became stable and had little\nfluctuation starting from the 6th day of the release. Drug concentration of DST and\nCST decreased gradually and the rate of decrease in concentration was faster in DST\nthan CST. MTT cytotoxicity test and direct contact test indicated that the INH-PLLA\ntablet had low cytotoxicity and favorable biocompatibility.\nConclusions: Three dimensional printing technique was a reliable technique to\nfabricate complicated implants. Drug release pattern in MDST was the most stable\namong the three implants. It was an ideal drug delivery system for the antibiotics.\nBiocompatibility tests demonstrated that the INH-PLLA implant did not have\ncytotoxicity. The multilayer donut-shaped tablet provided a new constant slow\nrelease method after an initial burst for the topical application of the antibiotic....
Background: Orthodontic palatal expansion appliances have been widely used with satisfactory and, most often,\npredictable clinical results. Recently, clinicians have successfully utilized micro-implants with palatal expander designs to\nwork as anchors to the palate to achieve more efficient skeletal expansion and to decrease undesired dental effects. The\npurpose of the study was to use finite element method (FEM) to determine the stress distribution and displacement\nwithin the craniofacial complex when simulated conventional and micro-implant-assisted rapid palatal expansion\n(MARPE) expansion forces are applied to the maxilla. The simulated stress distribution produced within the palate and\nmaxillary buttresses in addition to the displacement and rotation of the maxilla could then be analyzed to determine if\nmicro-implants aid in skeletal expansion.\nMethods: A three-dimensional (3D) mesh model of the cranium with associated maxillary sutures was developed using\ncomputed tomography (CT) images and Mimics modeling software. To compare transverse expansion stresses in rapid\npalatal expansion (RPE) and MARPE, expansion forces were distributed to differing points on the maxilla and evaluated\nwith ANSYS simulation software.\nResults: The stresses distributed from forces applied to the maxillary teeth are distributed mainly along the trajectories\nof the three maxillary buttresses. In comparison, the MARPE showed tension and compression directed to the palate,\nwhile showing less rotation, and tipping of the maxillary complex. In addition, the conventional hyrax displayed a\nrotation of the maxilla around the teeth as opposed to the midpalatal suture of the MARPE. This data suggests that the\nMARPE causes the maxilla to bend laterally, while preventing unwanted rotation of the complex.\nConclusions: In conclusion, the MARPE may be beneficial for hyperdivergent patients, or those that have already\nexperienced closure of the midpalatal suture, who require palatal expansion and would worsen from buccal tipping of\nthe teeth or maxillary complex...
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