RESUMO
BACKGROUND:For severe thoracolumbar compression fracture (>1/3 compression), ideal therapeutic method is minimal y invasive internal fixation, which has good biomechanical functions. Moreover, bone graft is reliable. Injured vertebra reduction and bone graft stability achieved. Motor unit of spinal column and normal physiological function were retained, resulting in lessening nearby segmental degeneration. OBJECTIVE:To discuss the design of single vertebrae internal fixation system and evaluate its biomechanical performance which apply to treat thoracolumbar compression fracture by endoscope. METHODS:A brand-new single vertebrae internal fixation system was designed in accordance with data of anatomic measurement of adult thoracolumbar vertebra. Six fresh adult corpse specimens were prepared to produce models of L 1 compression fracture, and assigned to control group, fracture injury group, single vertebrae internal fixation system group, AF reduction internal fixation group and anterior plate internal fixation group.Three-dimensional movement range experiments were conducted separately. RESULTS AND CONCLUSION:The biomechanical comparison showed that there was no significant difference in three-dimensional range of motion among single vertebrae internal fixation system group (anteflexion, left and right lateroflexion), AF reduction internal fixation group and anterior plate internal fixation group (P>0.05). However, range of motion significantly increased at backward extension, left and right rotation (P<0.05). Results suggested that the design of single vertebrae internal fixation system was novel and the system had good biomechanical performance at anteflexion, left and right lateroflexion. However, it needs to be improved in which lacks of stability of extension and rotation.