Abstract:

Objective　To evaluate the biomechanical properties of the aliform memory alloy intrasegmental fixation instrument (AMAIFI) for lumbar spondylolysis.　Methods　L4/5 functional spinal units from 8 fresh pig cadavers were used in the test, which were grouped into: the normal spine group, the lumbar spondylolysis group, the Buck's screw group, the Nicol's wire fixation group and the aliform memory alloy the intrasegmental fixation group. The movement range of each group was measured under the kinetic state of flexion/extension, left/right lateral bending, and left/right axial rotation.　Results　Under the state of flexion/extension and left/right axial rotation, the stability of the lumbar spondylolysis group was the worst，and had a significant difference with the other groups (P<0.05). The stability of spondylolysis lumbar could be restored distinctly in the group fixed with AMAIFI, and had no significant difference with the normal spine group and the other 2 intrafixation groups (P>0.05). Under the state of the left/right lateral bending，there was no significant difference among the various groups (P>0.05). 　Conclusions　The newly designed AMAIFI can restore the stability of spondylolysis lumbar with its operationf; Consequently, it can be assumed hat AMAIFI has a better application in the future.

Key words:  Lumbar spondylolysis;   , Memory alloy;    , Intrasegmental fixation;     , Biomechanics