Biomechanical Finite Element Analysis of Percutaneous Endoscopic Lumbar Discectomy via a Transforaminal Approach

OBJECTIVE: Based on the previously established 3dimensional model, this study uses the finite element analytical method to observe the effects of superior articlar process resection and intervertebral discectomy on the stress of the surgical segment under different motion states. METHODS: A validated L3-S1 finite element model was modified for simulation. And on the basis of the normal lumbar spine model, the superior articular process and discs of different parts of L4-L5 were simulated for resection. The resection models were divided into 6 groups, and the stress characteristics of articular process and discs of the lumbar spine under different postoperative motion conditions were examined under the same loading conditions.- RESULTS: Simultaneous resection of the tip and base of the superior articular process increased the stress on the facet joint under various motion states compared with separate resections. In addition, the fewer herniated discs that are removed, the smaller the increase in facet joint stress. excision of the tip of the superior articular process caused a smaller stress increase in the facet joint than excision of the base under the forward bending and rightlateral flexion, and the opposite results were found under left-lateral flexion, posterior extension, and rotation. Resection of the tip of the superior articular process increases disc stress more than resection of the base of the superior articular process.- CONCLUSIONS: Select resection of the superior articu lar process base as much as possible to expose the target of the disc. And minimize annulus damage and disc removal.