| Summary of Background Data: Burst fractures of the thoracolumbar spine are common and often result in significant disability. The treatment of these injuries has evolved rapidly over the past severl decades. Operative stabilization is often performed because of ability to reduce the fracture, protect the neural elements, and provide for earlier mobilization and ambulation of the patients. The most common mothed of spinal stabilization has been posterior rod instrumentation using sublaminar hook. By primarily using distraction and ligamentotaxis, the deformity and retropulsed fragments often could be reduced. Because of the inability to completely reduce retropulsed fragments and reduce the kyphotic deformity, however, alternative methods of stabilization were developed. The posterior transpedicular systems offer the adavantages of better control of kyphosis reduction, and limiting fusion to one level above and below the fracture.Even posterior transpedicular systems, however, do not always effectively clear the spinal canal. Many surgeons have advocated a two-stage approach whereby the posterior reduction is first performed, the patient resrudied, and should canal compromise continue, an anterolateral corpectomy for spinal canal decompression is performed. With the introduction of anterior spinal fixation devices, this two-stage procedurecould be performed in a single anterior approach, complete clearance of the spinal canal, and immediate stabilization for early mobilization of the patient. However, lesions involving both anterior and posterior spinal structures may require combined anterior and posterior decompression procedures and circumferential stabilization. Reconstruction methods to be used after corpectomy may depend on the extent of element involvement. To date, however, it remains unclear what extent of bone destruction requires anterior reconstruction alone versus posterior alone, combined anterior and posterior stabilization. The purpose of the present study was to compare the biomechanical stability provide by anterior Z-plate fixation device, posterior Tenor transpddicular system, and combined instrumentations in human caddveric spine model with burst fracture.Objective: To evaluation the biomechanical stability of short-segment anterior Z-plate fixation device, posterior Tenor transpedicular system, and combined instrumentations procedures for management of lumbar spine burst fracture.Methods: Ten fresh human cadaveric lumbar spine specimens were prepared for biomechanical testing. At harvest, muscle tissue was removed from the spines, but all intervertebral ligaments and facet capsules were left intact, all structures superior to the L1 end plate and inferior to the L5 end plate were excised and kept frozen in plastic bags at -20℃. Burst fracture was created on each L3 tebraverl body by simple axial compression using a high-speed trauma model(0ne was failure). Anterior reconstruction was performed between L2 and L4 using anautogenous bone strut graft and the Z-plate device for three models. Posterior reconstruction was accomplished between L2 and L4 using the Tenor device through the pedicle for three models. For circumferential reconstruction, the Tenor device and Z-plate device was combined with anterior autogenous bone struct graft in three models. Pure moments of flexion-extension, left-right axial torsion, and left-right lateral bending were applied to the top vertebra in a flexibility machine, and the motion of the L3 vertebral and adjacent discses were recorded with a motion measurement system after preconditioning. Three anterior, posterior and combined instrumentations fixative constructiones were test and load-displacement cures were abtained.Results: The anterior instrumentation provided less potential stability than combined instrumentations in flexion-extension, left-right axial torsion, and left-right lateral bending motion directions. Posterior instrumentation provided greater rigidity than the anterior Z-plate, except flexion and right lateral bending. Th... |
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