[Biomechanical evaluation of monosegmental and bisegmental anterior fixation for thoracolumbar burst fracture]

This paper is aimed to evaluate the biomechanism of monosegmental and bisegmental anterior fixation for thoracolumbar burst fracture. Twenty-four fresh porcine spines (T13-L3) were used in this study. Three of the fresh porcine spines were randomly selected as intact group, and the others were made into L1 burst fracture models. Fifteen of the twenty one fracture models fitting to the experimental requirements were divided randomly into five groups. Each of the specimens in the five groups and in the intact group underwent the tests of load-strain, load-displacement, stiffness and extreme limit bisegmental fixation group (P<0.05) loading. Data for the monosegmental fixation were insignificantly different on the load- strain and load-displacement tests from those for the bisegmental fixation (P>0.05), but were significantly different from those of the bisegmental fixation on the stiffness test, torsion test and limit loading test. Anterior monosegmental fixation is more stable and has stronger strain of axial compression than the bisemental fixation group. Resect pedicle group is insignificantly different from the monosegmental fixation group,so it is important to keep the pedicle integrity of injured vertebral body in surgery. The biomechanical stability of monosegmental fixation is feasible for thoracolumbar burst fracture.