Finite Element Analysis and in Vitro Biomechanical Experiment on the Effect of Unilateral Partial Facetectomy Performed by Percutaneous Endoscopy on the Stability of Lumbar Spine

Abstract Purpose: To investigate the lumbar biomechanical effects of unilateral partial facetectomy (UPF) of different facet joint (FJ) portions under percutaneous endoscopy. Methods: A 3D finite element (FE) model of the lumbar spine and 40 fresh calf spine models were used to simulate UPF under a physiological load performed through 3 commonly used needle insertion points (IPs) : (1) The apex of the superior FJ (as the first IP), (2) The midpoint of the ventral side of the superior FJ (as the second IP), (3) The lowest point of the ventral side of the superior FJ (as the third IP). The range of motion (ROM) and the L4/5 intradiscal maximum pressure (IMP) were measured and analyzed under a physiological load in all models during flexion, extension, left-right lateral flexion, and left-right axial rotation. Results: When UPF was performed through the first and the third IPs, the ROM of the lumbar spine and the L4/5 IMP in the FE model were significantly increased compared with those in the intact FE model. When UPF was performed through the second IP, the ROM of the lumbar spine and the L4/5 IMP were not significantly different compared with those in the intact FE model. When UPF was performed through the second IP, the ROM of the lumbar spine and the L4/5 IMP in the calf spine models were not statistically different from the intact calf spine model. Conclusion: UPF through the second IP resulted in a minimal impact on the biomechanics of the lumbar spine. Thus, it might be considered as the most appropriate IP for UPF.