An Experimental Method for Stereolithic Mandible Fabrication and Image Preparation

Reproduction of anatomical structures by rapid prototyping has proven to be a valid adjunct for craniofacial surgery, providing alternative methods to produce prostheses and development of surgical guides. The aim of this study was to introduce a methodology to fabricate asymmetric human mandibles by rapid prototyping to be used in future studies for evaluating mandibular symmetries. Stereolithic models of human mandibles were produced with varying amounts of asymmetry in the condylar neck, ramus and body of the mandible by means of rapid prototyping. A method for production of the synthetic mandibles was defined. Model preparation, landmark description and development of the experimental model were described. A series of synthetic mandibles ranging in asymmetry were accurately produced from a scanned human mandible. A method for creating the asymmetries, fabricating, coating and landmarking the synthetic mandibles was formulated. A description for designing a reproducible experimental model for image acquisition was also outlined. Production of synthetic mandibles by stereolithic modeling is a viable method for creating skeletal experimental models with known amounts of asymmetry

Axial length and choroidal thickness changes accompanying prolonged accommodation in myopes and emmetropes

The time course of elongation and recovery of axial length associated with a 30 minute accommodative task was studied using optical low coherence reflectometry in a population of young adult myopic (n = 37) and emmetropic (n = 22) subjects. Ten of the 59 subjects were excluded from analysis either due to inconsistent accommodative response, or incomplete anterior biometry data. Those subjects with valid data (n = 49) were found to exhibit a significant axial elongation immediately following the commencement of a 30 minute, 4 D accommodation task, which was sustained for the duration of the task, and ¬was evident to a lesser extent immediately following task cessation. During the accommodation task, on average, the myopic subjects exhibited 22 ± 34 µm, and the emmetropic subjects 6 ± 22 µm of axial elongation, however the differences in axial elongation between the myopic and emmetropic subjects were not statistically significant (p = 0.136). Immediately following the completion of the task, the myopic subjects still exhibited an axial elongation (mean magnitude 12 ± 28 µm), that was significantly greater (p < 0.05) than the changes in axial length observed in the emmetropic subjects (mean change -3 ± 16 µm). Axial length had returned to baseline levels 10 minutes after completion of the accommodation task. The time for recovery from accommodation-induced axial elongation was greater in myopes, which may reflect differences in the biomechanical properties of the globe associated with refractive error. Changes in subfoveal choroidal thickness were able to be measured in 37 of the 59 subjects, and a small amount of choroidal thinning was observed during the accommodation task that was statistically significant in the myopic subjects (p < 0.05). These subfoveal choroidal changes could account for some but not all of the increased axial length during accommodation

Densitometric Evaluation of Spiraeoside after Derivatization in Flowers of Filipendula Ulmaria (L.) Maxim

Spiraeoside (quercetin-4'-glucoside) is the major and most caharacteristic flavonoid of Filipendula ulmaria flowers and is not found in the leaves and stems. This paper describes a quantification of spiraeoside by HPTLC densitometry after derivatization with diphenylboric acid -2-aminoester. The fluorescence of this flavonoid was measured at 330 nm. the spiraeoside content in batches of Filipendula ulmaria flowers ranged from 3 to 4.3 %. It is of note that these results are similar to those published elsewhere after HPLC analysis of other batches

Aplication of the stereolithography technique in complex spine surgery Aplicação da técnica de estereolitografia em cirurgias complexas da coluna

Many techniques have been proposed for surgical training as a learning process for young surgeons or for the simulation of complex procedures. Stereolithograpfy, a rapid prototyping technique, has been presented recently as an option for these purposes. We describe the case of a 12 years old boy, diagnosed with Ewing&acute;s sarcoma in the cervical spine. After a surgical simulation accomplished in the prototype, built by stereolithography, the patient was submitted to a C4 corpectomy and to a C4 and C3 laminectomy with anterior and posterior fixation, a non intercurrence procedure. This technique is an innovative and complementary tool in diagnosis and therapy. As a result, it is easier for the surgeon to understand the complexity of the case and plan the approach before any surgical procedure.<br>Lesões tumorais da coluna podem representar um grande desafio para equipe cirúrgica. A estereolitografia é uma técnica de construção de peças anatômicas a partir de desenhos gráficos ou exames radiológicos. Apresentamos um paciente de 12 anos, com quadro de cervicobraquialgia à direita com diagnóstico de sarcoma de Ewing. Ao exame neurológico, o paciente apresentava-se com paresia em MSD grau IV e leve hipoestesia em dermátomos de C6 à T1 à direita. RM evidenciou edema intra e extra-ósseo com compressão medular e instabilidade cervical. Realizada simulação cirúrgica no protótipo construído por estereolitografia. Foi submetido a corpectomia de C4 e a laminectomia C4 e C3, com fixação anterior e posterior, procedimento sem intercorrências. A estereolitografia é ferramenta inovadora no auxílio diagnóstico e terapêutico. Seu uso permite ao cirurgião entender fisicamente o sítio da lesão, estudar a via de acesso e perceber a real complexidade do caso antes do procedimento cirúrgico