The biomechanical effects of foraminoplasty of different areas under lumbar percutaneous endoscopy on intervertebral discs: A 3D finite element analysis

摘要

Background: We set out to evaluate the biomechanical influence of foraminoplasty on intervertebral discs in different areas under lumber percutaneous endoscopy through the use of a three-dimensional finite element. Methods: We established a normal 3D finite element mode of L 3–5 , using simulate lumbar percutaneous endoscopy by carrying out cylindrical excision of a bone whose diameter was 7.5 mm on the L 5 superior articular process and the L 4 inferior articular process, respectively. We therefore obtained 3 models. The first was the normal lumbar model, the second the L 4 inferior articular process shaped model, while the third was the L 5 superior articular process shaped model. We compared the biomechanics of discs of L 3/4 and L 4/5 in states of forward flexion, backward extension, left and right flexion as well as left and right rotation. Results: When the L 4 inferior articular process shaped model was in backward extension, left rotation, and right rotation, the stress of the L 4/5 disc was greater than in the normal model, especially in the state of extension. When the L 5 superior articular process shaped model was in left and right rotation, the biggest stress of the L 4/5 disc increased slightly. However, no matter which way the L 5 superior articular process or the L 4 inferior articular process of model was shaped, the stress impact of the L 3/4 disc was small. Conclusions: There is more biomechanical influence on the L 4/5 disc when carrying out a foraminoplasty on L 4 inferior articular process under a lumber percutaneous endoscopy. In addition, the influence of both types of surgery on the stress of L 3/4 disc is small.