Biomechanical evaluation of the U shape lumbar biological dynamic fixation system / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To evaluate biomechanical characteristics of a new U-shaped lumbar bioelastic internal fixation deuice (UBD).</p><p><b>METHODS</b>Six fresh calf lumbar (L2-L5) samples were divided into 4 groups, namely the normal group, traumatic instability group, instability group with rigid internal fixation and instability group with UBD fixation. The vertebral 3-dimensional range of motion (ROM) and rigidity of the 4 group were tested.</p><p><b>RESULTS</b>Elastic fixation and rigid fixation both significantly increased vertebral segment stability for flexion, extension, lateral curvature and rotations. Compared with rigid fixation, elastic fixation obviously increased the ROM by 2.22 degrees in flexion and extension, but significantly decreased the rigidity in forward bending and backward bending and compression (P<0.01).</p><p><b>CONCLUSION</b>The UBD may enhance the load sharing and decrease stress-shielding and stress concentration without sacrificing lumbar stability.</p>