Effects of Facet Joint Arthroplasty at Different Positions under Lumbar Percutaneous Endoscopy on Range of Motion of Vertebral Bodies / 医用生物力学

ABSTRACT

Objective To evaluate the influence of facet joint arthroplasty at different positions under lumbar percutaneous endoscopy on range of motion (ROM) of vertebral bodies by using the three-dimensional (3D) finite element method. Methods The 3D finite element model of normal L3-5 segment was established, and lumbar percutaneous endoscopy was simulated by doing cylindrical excision of bone with diameter of 7.5 mm on the tip or basement of L5 facet joint, so as to obtain normal lumbar vertebra model, L5 facet joint model with shaped tip, L5 facet joint model with shaped basement, respectively. Given specific loading conditions, the ROMs of adjacent vertebral bodies for the 3 models under flexion, extension, left and right lateral flexion, left and right rotation were compared. Results When L5 facet joint tip was shaped, the ROMs of L4-5 under extension，left lateral flexion, right lateral flexion, left rotation and right rotation were obviously larger than those of the normal model, especially under left rotation. When the L5 facet joint basement was shaped, the ROMS of L4-5 under left and right rotation increased slightly compared with those of the normal model. However, the ROMs of L3-4 for both tip-shaped and basement-shaped L5 facet joint model showed no obvious changes under six different motions. Conclusions The influence of L5 facet joint with shaped tip on ROMs of L4-5 was relatively larger than that of L5 facet joint with shaped basement under lumber percutaneous endoscopy. There was no significant effect on the ROMs of L3-4 with L5 facet joint arthroplasty.