OBJECTIVE: To compare ultrasound propagation velocity with densitometry in the diaphyseal compact cortical bone of whole sheep metatarsals. METHODS: The transverse ultrasound velocity and bone mineral density of 5-cm-long diaphyseal bone segments were first measured. The bone segments were then divided into four groups of 15 segments each and demineralized in an aqueous 0.5 N hydrochloric acid solution for 6, 12, 24 or 36 hours. All measurements were repeated after demineralization for each time duration and the values measured before and after demineralization were compared. RESULTS: Ultrasound velocity and bone mineral density decreased with demineralization time, and most differences in the pre- and post-demineralization values within each group and between groups were significant: A moderate correlation coefficient (r=0.75956) together with a moderate agreement was determined between both post-demineralization parameters, detected by the Bland-Altman method. CONCLUSION: We conclude that both ultrasound velocity and bone mineral density decrease as a result of demineralization, thus indicating that bone mineral content is of great importance for maintaining the acoustic parameters of cortical bone, as observed for cancellous bone. Ultrasound velocity can be used to evaluate both compact cortical bone quality and bone mineral density.

Objective: To analyze the influence of steel plates for osteosynthesis on the velocity of ultrasound propagation (VU) through the bone.Methods: The transverse coronal and sagittal velocity of ultrasound propagation underwater were measured on the intact bone and then on assemblies of the same bone with two types of osteosynthesis plates (DCP and semi tubular), fixed onto the dorsal side of the bones. The first arriving signal (FAS) was the ultrasound parameter used, taking the coronal and sagittal diameters as the distances to calculate velocity. Intergroup statistical comparisons were made at significance level of 1% (p<0.01).Results: Velocity was higher on the intact bones than on the bone-plate assemblies and higher for the semitubular than for the compression plates, although differences were not statistically significant for most comparisons (p=0.0132 to 0.9884), indicating that the steel plates do not interfere significantly with ultrasound wave propagation through the bone-plate assemblies.Conclusion: The velocity reduction effect was attributed to the greater reflection coefficient of the steel as compared to that of bone and water. Ultrasonometry can, thus, be used in the evaluation of healing of fractures fixed with steel plates. Experimental Study.

OBJECTIVE: To compare normal and delayed bone healing by measuring ultrasound conduction velocity across the bone callus. METHODS: A model of transverse linear and 5 mm resection osteotomies of sheep tibiae was used. Fourteen sheep were operated on and were divided into two groups of seven according to osteotomy type. The procedure was performed on the right tibiae and the intact left tibiae were used as controls. The transverse and axial ultrasound velocities were measured at 30-day intervals for 90 days, after which the animals were killed and both the right and left tibiae were resected for in vitro biomechanical analysis. RESULTS: Both the transverse and axial ultrasound velocities progressively increased, but the increase was smaller for the delayed union that resulted from the resection osteotomy. The mechanical resistance was higher for the normally healed tibiae that resulted from a linear osteotomy; this result closely correlated with the ultrasound velocity results. Significant differences were found for the comparisons between the intact and operated tibiae in both groups and between the groups for both the transverse and axial ultrasound velocities, but the differences were greater for the latter. CONCLUSION: We conclude that in vivo transverse and axial ultrasound velocities provide highly precise information about the healing state of both linear and resection diaphyseal osteotomies, but the axial ultrasound velocity most likely has greater discriminatory power. This method has the potential for clinical application in humans.

OBJETIVO: Medir a velocidade de propagação do ultrassom (VU) através de uma osteotomia transversal em tíbias de ovelha, antes e após a fixação com uma placa DCP. MÉTODOS: Foram utilizadas dez montagens de uma placa DCP com o segmento diafisário das tíbias, no qual era feita uma osteotomia transversal. Foi realizada a medida subaquática transversal, nos planos coronal e sagital, e axial da VU, no osso íntegro, nas montagens sem osteotomia e, depois, com osteotomia sem e com a compressão axial pela placa DCP; comparações estatísticas foram feitas ao nível de significância de 1% (p<0,01). RESULTADOS: Em comparação com a montagem com o osso intacto, a VU diminuiu com a adição da osteotomia e aumentou com a compressão axial, com significância somente para a modalidade axial de medida da VU. CONCLUSÃO: Concluiu-se que esse dado pode ser aplicável ao acompanhamento pós-operatório das osteossíntese com placa DCP, com a capacidade de demonstrar quando esta se torna ineficiente. Trabalho experimental.

OBJECTIVE: To measure the ultrasound propagation velocity (UV) through a tibial transverse osteotomy in sheep, before and after the fixation with a DCP plate. MATERIAL AND METHODS: Ten assemblies of a DCP plate with the diaphyseal segment of tibiae, in which a transverse osteotomy was made, were used. Both coronal and sagittal transverse and the axial UV were measured, first with the intact bone assembled with the plate and then with the uncompressed and compressed osteotomy; statistical comparisons were made at the 1% (p<0.01) level of significance. RESULTS: Compared with the intact bone assembly, axial UV significantly decreased with the addition of the osteotomy and significantly increased with compression, presenting the same behavior for the other modalities, although not significantly. DISCUSSION AND CONCLUSION: In accordance with the literature data on the ultrasonometric evaluation of fracture healing, underwater UV measurement was able to demonstrate the efficiency of DCP plate fixation. The authors conclude that the method has a potential for clinical application in the postoperative follow-up of DCP plate osteosinthesis, with a capability to demonstrate when it becomes ineffective. Laboratory investigation.

Foi realizado um estudo experimental sobre o desenvolvimento e desempenho de um fixador externo flexível no processo de consolidação de tíbias de carneiros submetidas à osteotomia transversa mediodiafisária. Foram empregados no estudo 20 carneiros da raça Santa Inês, com massa corporal média de 37kg, divididos em diferentes grupos conforme o período de observação pós-operatória, de 30, 45, 60 e 90 dias. Ao final, os animais sofreram a eutanásia e as tíbias foram removidas para estudo de volumetria transversal do calo ósseo por tomografia computadorizada e ensaio mecânico destrutivo. Os resultados mostraram que ocorreu a formação de calo ósseo volumoso, caracterizando assim a ocorrência de deslocamento de carga axial para o foco da osteotomia, promovida pelo fixador externo utilizado. No ensaio mecânico, observou-se que as comparações entre os grupos respectivos intactos e operados foram significantemente diferentes (P<0,05), com exceção do grupo com 90 dias, demonstrando haver rigidez equivalente ao osso normal. Em nenhum dos animais, houve desenvolvimento de pseudoartroses ou não união óssea. Diante dos resultados, conclui-se que o uso do fixador com haste flexível abordado nesta pesquisa para o tratamento de fraturas dos ossos longos de animais de médio porte foi de fácil aplicação, reprodutível e recomendável.

An experimental study was carried out to verify the development and performance of a flexible external fixator on the bone healing process of the tibia of sheep submitted to a transverse diaphyseal osteotomy. It was used twenty Santa Inês sheep with average weigh of 37kg divided in groups, according to the period of postoperative observation of 30, 45, 60 and 90 days. At the end, the animals were sacrificed and the tibiae were removed for study of transverse callus volumetric by computed tomography and destructive mechanical testing. The results had shown that the formation of voluminous callus occurred, thus characterizing the occurrence of displacement of axial load to the focus of the osteotomy, promoted by the used external fixator used. The mechanical testing showed that the comparisons between the respective intact and operated groups were significantly different (P<0.05) except for the group with 90 days, which demonstrated equivalent stiffness when compared to normal bone. In none of the animals there was development of pseudarthrosis or non-union of the bone. Given the results, it was conclude that the use of the flexible fixator covered in this research for treatment of long bones fractures in medium animals was easy to apply, reproducible and recommended.

Métodos histológicos e eletrofisiológicos de avaliação da regeneração dos nervos periféricos não provêem dados sobre o real estado funcional do membro interessado, mesmo em condições experimentais controladas. Alguns métodos de avaliação funcional têm sido propostos, mas a correlação entre seus resultados e aqueles dos métodos histológicos e eletrofisiológicos ainda não está perfeitamente estabelecida, o que demanda maiores investigações. Estas, por outro lado, necessitam do aprimoramento dos métodos de captação, armazenamento e processamento dos dados obtidos. Neste trabalho foi desenvolvido uma esteira para caminhada de animais com velocidade controlada para captação das pegadas de ratos submetidos a diferentes tipos de lesão dos nervos ciático, peroneiro e tibial, obtidas numa trilha de marcha captada por uma webcam acoplada a esteira e a um microcomputador capaz de armazenar as marchas filmadas para posteriormente serem digitalizadas para avaliação funcional. A esteira desenvolvida possibilita a captação e filmagem das marchas tendo sido testado em estudos experimentais em andamento sobre lesões do nervo ciático do rato, submetido a diferentes formas de tratamento. Também permite ao pesquisador a captação da marcha com velocidade contínua controlada e pré-estabelecida pelo pesquisador anulando algumas variáveis que possam prejudicar os resultados da pesquisa, além de permitir a visualização imediata da marcha.

Histological and electrophysiological methods for evaluation of peripheral nerve regeneration do not faithfully reproduce the functional index of limbs, even in controlled experimental conditions. Some methods of functional evaluation have been proposed, but their correlation to histological and electrophysiological data is not completely established, requiring more investigations with improvement of collection, management and processing of obtained data. In this study we developed a treadmill with controlled speed for recording footprint of rats submitted to different kinds of sciatic, fibular and tibial nerve lesions. The footprints were obtained on a walking track by means of a webcam connected to the treadmill and a computer with capacity to record the gait that will be submitted to functional evaluation. The developed treadmill allows the collection and filming of gaits and it has been tested in current experimental studies in rats with sciatic nerve lesion submitted to different kinds of treatment. The treadmill also enables researchers to record gait with constant, controlled and pre-established speed, with the possibility of direct visualization through the treadmill wall. In this manner, some variables that could damage the results of the research are resolved.

OBJETIVO: Foi nosso objetivo, desenvolver uma pinça regulável que permite produzir uma lesão com carga conhecida, num segmento de 5 mm de comprimento do nervo isquiático de ratos. MÉTODOS: O material escolhido para confecção da pinça foi o aço inoxidável, pela sua maior durabilidade e possibilidade de esterilização com soluções anti-sépticas, quase sempre corrosivas. A carga de esmagamento da pinça é regulável, pelo aumento ou diminuição da tensão da mola que a aciona, por meio de um parafuso de regulagem de calibração, feita com uma célula de carga. RESULTADO: A pinça foi utilizada em investigações experimentais e mostrou-se tão eficiente quanto as máquinas de ensaio e de peso morto anteriormente utilizadas. CONCLUSÃO: A pinça desenvolvida apresenta vantagens de ser portátil, de fácil manuseio, baixo custo e permite padronização da carga aplicada.

OBJECTIVE: A new adjustable pinch has been developed for producing a crush injury, with a previously known load of 5 kg, on a 5 mm-long segment of the nerve. METHODS: Stainless steel was the material selected for building the pinch due its durability and possibility of sterilization with anti-septic substances, which are often corrosive. The crushing load of the pinch is adjustable by increasing or decreasing the tension of the spring by means of a screw used for calibration, which is performed by a load cell. RESULT: This pinch has been used in a few experimental investigations and was shown to be as efficient as both the universal testing machine and the dead weight machine, previously used. CONCLUSION: The developed pinch has the advantages of being portable and user-friendly. In addition, the pinch is cheap and allows for the standardization of the applied load.

OBJETIVO: O objetivo deste trabalho foi comparar a velocidade e atenuação ultra-sônica, na avaliação in vitro da consolidação óssea. MÉTODO: Foram empregados no estudo 17 carneiros, com massa corporal média de 37 kg, divididos entre grupos controle e três experimentais, conforme o período de observação pós-operatória de 30, 60 e 90 dias. As osteotomias foram realizadas nas tíbias direitas dos animais, ficando as esquerdas como controle. O processo de consolidação foi acompanhado por meio de avaliação radiográfica a cada duas semanas. Ao fim do período de observação estipulado para cada grupo, os animais sofreram eutanásia e as tíbias foram removidas para a análise ultra-sonométrica in vitro. Foram medidos e correlacionados a velocidade de propagação transversal e longitudinal do ultra-som e a atenuação do ultra-som (BUA) transversal na região da osteotomia. RESULTADOS: A velocidade de propagação do ultra-som (transversal e longitudinal, in vitro) aumentou com o avançar da consolidação, sendo as diferenças significantes em relação ao grupo controle e entre a maioria dos grupos experimentais. Já a BUA diminuiu, sendo parte das diferenças significantes entre os grupos. CONCLUSÃO: O método de avaliação da consolidação pelos parâmetros da ultra-sonometria é factível, com resultados confiáveis e precisos para medir a consolidação óssea.

OBJECTIVES: The objective of this study was to compare the in vitro ultrasonic velocity and attenuation in bone healing evaluation. METHODS: Seventeen sheep weighting 37 kg in average were used, being divided into two groups of five animals each and one group of seven animals, according to the postoperative follow-up time (30, 60 and 90 days, respectively). Osteotomies were performed on the right tibiae and the intact left tibiae of the 17 animals were used as control. The healing process was monitored with conventional conventional radiographs taken at two-week intervals. The animals were sacrificed at the end of the corresponding followup period and both right and left tibiae were removed for in vitro underwater and contact ultrasound evaluations. The transverse and longitudinal ultrasound propagation velocity (USPV) and the broadband ultrasound attenuation (BUA) were measured and correlated. RESULTS: USPV increased with the progression of the healing process, while BUA decreased, with significant differences between the experimental and control groups and between the experimental groups, for most of the comparisons. CONCLUSION: It was concluded that the method using ultrasound as employed in this investigation is feasible and reliable for evaluating cortical bone healing.

Foi realizado um estudo experimental sobre a avaliação ultra-sonométrica da consolidação de tíbias de carneiros submetidas a osteotomia transversal mediodiafisária, utilizando 15 carneiros, com pêso médio de 37 Kg, divididos em três grupos experimentais de cinco animais cada, conforme o período de observação pós-operatória de 30, 45 e 60 dias. As osteotomias foram realizadas nas tíbias direitas dos animais, ficando as tíbias esquerdas como controle. Foi feita avaliação radiográfica da consolidação a cada duas semanas e, ao fim do período de observação, os animais foram sacrificados e as tíbias, removidas para a análise ultra-sonométrica. Foram medidos e correlacionados o diâmetro da tíbia e a velocidade de propagação transversal do ultra-som na região da osteotomia, em duas direções diferentes (perpendicular e paralela ao plano da tuberosidade anterior da tíbia). A velocidade de propagação do ultra-som aumentou com o avançar da consolidação (±5%), sendo as diferenças significantes em relação ao grupo-controle, mas não entre os grupo experimentais. Os diâmetros diminuíram nas duas direções medidas, sendo as diferenças significantes entre os grupos, com forte correlação negativa com a velocidade. Concluiu-se que o método de avaliação da consolidação pela ultra-sonometria é factível, com resultados confiáveis e precisos.

An experimental study on the ultrasonometric evaluation of the bone healing process of the tibia of sheep submitted to a transverse diaphyseal osteotomy for different periods was carried out using 15 sheep weighing 37 kg on average and divided in three groups of five according to the postoperative period of observation of 30, 45 and 60 days. The osteotomies were performed on the right tibiae while the left tibiae were left for control. Radiographic control was done at 2-week intervals and the animals were killed at the end of the period of observation for removal of the tibiae and ultrasonometric evaluation. Both diameter and ultrasound transverse propagation velocity were measured in two directions (perpendicular and parallel to the anterior tuberosity) at the osteotomy site and compared. The ultrasound propagation velocity increased with time (±5%), the differences between the experimental and control groups being significant, but not within the experimental groups. The diameters decreased in both directions, the differences between the experimental groups being significant, with a strong negative correlation with velocity. It was concluded that ultrasonometric evaluation of the bone healing process is feasible and the results are precise and reliable.