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BACKGROUND: Degenerative change in lumbar spine is the natural physiological and pathological process with age increasing, which seriously affects the patients' quality of life. Conventional surgical treatments may bring about some complications. Interspinous stabilization Coflex demonstrates good clinical outcomes, while there is lack of experimental evidence.OBJECTIVE: To investigate the effect of fixation methods on the movement of lumbar vertebrae, and to provide reference for clinical operation from the aspect of biomechanics.METHODS: Five fresh specimens of pig cadaveric lumbar spine were selected and divided into five groups: blank control group (group A), injury group (group B), L3-L4 Coflex fixed (group C), L3-L4 Coflex fixed plus decompression (group D),and L3-L4 intervertebral fusion fixed (group E). The biomechanical performance of the five lumbar specimens was tested in six loading directions of flexion/extension, left/right lateral bending, and left/right axial rotation driven by a robot system.The motion range of the operation segments (L3-L4) and the whole lumbar spine was observed by a multi-directional torque sensor combined with a three-dimensional motion capture system. Finally, the influence of lumber fixation methods on the spinal movement was explored.RESULTS AND CONCLUSION: (1) For the range of three-dimensional angle at the operation segments (L3-L4), it was found that groups C and D were similar to group A, and groups B and E were quite different from group A. (2) Group E could restore the motion range of the injured segments, but the motion angle was much smaller than that in the groups C and D. (3) These results indicate that the motion angle of the injured spine treated with Coflex can restore to the normal state, with long-term stability. For unstable lumbar spine, interspinous Coflex is better than transforaminal lumbar interbody fusion, which can induce similar biomechanical properties to normal lumbar spine after operation.
RESUMO
PURPOSE: The aim of this study was to determine the relationship of hypoxia-inducible factor-2 (HIF-2α) and vascular endothelial growth factor (VEGF) with radiographic severity in primary osteoarthritis (OA) of the knee. Expression of these two factors in cartilage samples from OA knee joints was examined at mRNA and protein levels. MATERIALS AND METHODS: Knee joints were examined using plain radiographs, and OA severity was assessed using the Kellgren and Lawrence (KL) grading system. Specimens were collected from 29 patients (31 knees) who underwent total knee replacement because of severe medial OA of the knee (KL grades 3 and 4), 16 patients who underwent knee arthroscopy (KL grade 2), and 5 patients with traumatic knees (KL grade 0). HIF-2α and VEGF expression was quantified by real-time polymerase chain reaction and western blotting. RESULTS: Cartilage degeneration correlated with the radiographic severity grade. OA severity, determined using the Mankin scale, correlated positively with the KL grade (r=0.8790, p<0.01), and HIF-2α and VEGF levels with the radiographic severity of knee OA (r=0.7001, p<0.05; r=0.6647, p<0.05). CONCLUSION: In OA cartilage, HIF-2α and VEGF mRNA and protein levels were significantly and positively correlated. The expression of both factors correlated positively with the KL grade. HIF-2α and VEGF, therefore, may serve as biochemical markers as well as potential therapeutic targets in knee OA.