RESUMO
BACKGROUND:The finite element analysis method is more accurate and fast to construct the three-dimensional model of the human skeleton and design the bone surgical medical instrument. OBJECTIVE:To establish locking plate model according to the clavicle model, analyze and evaluate stress distribution of locking plate of the finite element model under bending and torsion conditions. METHODS:Chest scan was carried out in a healthy young adult male by adopting 64-row spiral CT and his two-dimensional image data were gotten. The obtained data were analyzed with Mimics 10.0 software to establish the three-dimensional clavicle finite element model. The clavicle locking fixation plate model was established by applying the UG software. The locking fixation plate was evaluated by utilizing the abaqus software when the plate was bent while down to give force of 200 N, and twisted while 200 N?mm, to simulate the force and analyze the stress distribution of the locking plate. RESULTS AND CONCLUSION:Based on the original image parameters provided by CT, this experiment produced a three-dimensional model of the clavical titanium plate which fitted better to bones. This model can obtain a single individual, personalized plate by three-dimensional printing technology. The finite element analysis basical y can simulate the actual stress of the plate. For straight plate and“S”-shape plate, in lateral bending and axial torsion loads, the maximum stress distribution of the seven-hole titanium plate is located in the center of the center hole. During actual surgical procedures, clavicle fracture fragments and middle locking hole had stress superposition. If the titanium plate can avoid the stress concentration, it can effectively avoid the occurrence of the broken plate after implantation, provide theoretical guidance for clinical practice, and provide reference and technical route for biomechanical analysis of other types of titanium plate.
RESUMO
BACKGROUND:The narrowing of intervertebral space induced by the intervertebral disc degeneration is mainly characterized by the expression of proteoglycan in nucleus pulposus cells and the reduction of col agen type II. OBJECTIVE:To quantitatively observe col agen type II protein in adult normal and degenerative intervertebral disc nucleus pulposus cells by immunofluorescence staining and safranin O staining. METHODS:The nucleus pulposus specimens were col ected from adult scoliosis patients and patients with intervertebral disc protrusion, who were al volunteers. After culture, 26 cells in each patient were measured. There were 78 cells in both normal group and degeneration group. The normal and degenerative intervertebral disc nucleus pulposus cells were subjected to safranin“O”staining, and gray values were determined;intracellular col agen type II was detected by immunofluorescence staining. RESULTS AND CONCLUSION:Immunofluorescence staining revealed that, degenerative intervertebral disc nucleus pulposus cells were only mildly stained, with the fuzzy staining, the shape was round, spindle, fusiform and irregular. There were a very smal amount of fluorescent particles within cells. The expression of col agen type II was decreased significantly compared with normal cells (P0.05). The degenerative intervertebral disc nucleus pulposus cells have a smal quantity and partial y become apoptotic, the content of col egen type II protein is decreased significantly compared with normal nucleus pulposus cells.