The biomechanical effects of foraminoplasty of different areas under lumbar percutaneous endoscopy on intervertebral discs

Abstract

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 L3–5, using simulate lumbar percutaneous endoscopy by carrying out cylindrical excision of a bone whose diameter was 7.5 mm on the L5 superior articular process and the L4 inferior articular process, respectively. We therefore obtained 3 models. The first was the normal lumbar model, the second the L4 inferior articular process shaped model, while the third was the L5 superior articular process shaped model. We compared the biomechanics of discs of L3/4 and L4/5 in states of forward flexion, backward extension, left and right flexion as well as left and right rotation. Results: When the L4 inferior articular process shaped model was in backward extension, left rotation, and right rotation, the stress of the L4/5 disc was greater than in the normal model, especially in the state of extension. When the L5 superior articular process shaped model was in left and right rotation, the biggest stress of the L4/5 disc increased slightly. However, no matter which way the L5 superior articular process or the L4 inferior articular process of model was shaped, the stress impact of the L3/4 disc was small. Conclusions: There is more biomechanical influence on the L4/5 disc when carrying out a foraminoplasty on L4 inferior articular process under a lumber percutaneous endoscopy. In addition, the influence of both types of surgery on the stress of L3/4 disc is small.

Visible trephine-based foraminoplasty in PTED leads to asymmetrical stress changes and instability in the surgical and adjacent segments: a finite element analysis

“…However, the stress of L4-5 disks increased significantly after molding, with an increase of less than 9% in Group B and 26% in Group C, while the disk stress of the DE group could increase up to a maximum of 44%. These findings were consistent with those observed by Xie et al [ 23 ] and Li et al [ 27 ], where simple ventral SAP resection had a minimal effect on disk stress, but extended ventral resection or SAP shoulder resection could affect the overall bearing of the facet, thus increasing the disk stress of L45. This increase in disk stress may result in postoperative L45 disk stress concentration, leading to possible recurrence of disk herniation or accelerated space degeneration.…”

“…Multiple studies have reported the role of the lumbar zygapophysial articular cartilage plays in maintaining the overall stability of the lumbar spine and protecting the annulus fibrosus [ 22 , 23 ]. Spine surgeons traditionally believed that varying types of facet facetectomy have little impact on postoperative stability [ 24 ].…”

Quantifying Lumbar Foraminal Volumetric Dimensions: Normative Data and Implications for Stenosis—Part 2 of a Comprehensive Series

“…Our volumetric analysis, grounded in a precise and replicable formula, offers a framework for integrating quantitative imaging assessments into the diagnostic process for lumbar spinal disorders. By establishing normative data for lumbar foraminal volumes, our study paves the way for developing diagnostic criteria and thresholds that can be applied in clinical settings to differentiate normal anatomical variations from clinically significant stenosis ( Figure 4 ) [ 54 , 55 , 56 ].…”