A finite element analysis on different bone cement forms and injection volumes injected into lumbar vertebral body in percutaneous kyphoplasty

Abstract

Background To investigate the stress changes between different bone cement forms and injection volumes in adjacent vertebrae after percutaneous kyphoplasty (PKP) by establishing a three-dimensional finite element model of osteoporosis. Methods A male healthy volunteer was selected. CT of scans L1 to L3 vertebrae were imported into Mimics 21.0 software.The vertebral model of osteoporosiswas established based on previous literature reference. The models were divided into three groups: unilateral, bilateral integration and bilateral separation groups, with each group injecting 2 ml, 4,ml and 6 ml of bone cement, respectively. In all models, a vertical compressive load of 500 N, anterior flexion/posterior extension, left/right bending, and left/right rotation were applied with a moment of 7.5 N/m, of which 85% was applied to the anterior mid-column and 15% to the posterior column. The stress changes between adjacent vertebrae under different conditions were calculated. Results After percutaneous kyphoplasty was applied to the L2 vertebral body, some differences can be found between the effects of different cement injection volumes and cement morphology on adjacent structures. There was no major difference between the groups when the bone cement injection volume was 2 ml. When the amount of bone cement injected was 4 ml, the bone cement morphology of the bilateral integration group (BIG) produced less stress between adjacent vertebral bodies. The minimum stress was 14.95 MPa in the L3 vertebral body in posterior extension. Whereas the stress levels on adjacent intervertebral structures, BIG shaped bone cement shows some superiority. In addition, the adjacent vertebrae and intervertebral structures are subjected to less stress during left and right rotation. Conclusions The present finite element study suggested that bilateral integration bone cement is a suitable form of cement injection, and when the injection volume is 4 ml, reduces stress on adjacent segments by approximately 15% while maintaining the stability of the injected vertebral body.

Spatiotemporal Regulation of Injectable Heterogeneous Silk Gel Scaffolds for Accelerating Guided Vertebral Repair

“…Zhang et al reported the injection volume of bone cement also affects the stress on adjacent segments, this prompts us to conduct further study to optimize the use of silk hydrogel. [63] FEA results further suggested the uniform stress dispersion of silk gel scaffold compared with PMMA and osteoporotic trabecula (Figure 4e). Trabecular bone filled with silk demonstrated a decrease in peak stress by about 38-50% under the same compressive deformation loading condition.…”

“…Zhang et al reported the injection volume of bone cement also affects the stress on adjacent segments, this prompts us to conduct further study to optimize the use of silk hydrogel. [ 63 ]…”

A 20-Year Review of Biomechanical Experimental Studies on Spine Implants Used for Percutaneous Surgical Repair of Vertebral Compression Fractures

“…Although finite element computational studies of the biomechanics of VCF repair was not the focus of this review, some remarks should be made. Great improvements in computational tools in recent years have encouraged some researchers to utilize finite element models, rather than costly experiments to investigate VCF treatments [12,39,[56][57][58][59][60][61][62][63][64][65][66][67][68]. However, the best way to model VCF fixation is still a controversial topic.…”

“…The cancellous region around the cement and/or implant can often be compacted during VCF treatment, which can alter the mechanical stresses on surrounding structures [60]. The vertebral bone is commonly modeled as osteoporotic to mimic older patients [65][66][67][68], but normal bone quality can also be easily simulated if younger patients are of concern. The shape, size, and material of the implant itself can be optimized [39,64], while the implant can be used alone or combined with other spine fusion devices [65].…”

“…However, the best way to model VCF fixation is still a controversial topic. For instance, the shape of the cement bolus can be modelled in different ways [ 12 , 68 ]: (a) an idealized barrel, ellipsoid, spheroid, or torus; (b) the shape of the host vertebra itself; or (c) realistic cement shapes based on medical imaging scans of patients with injured vertebrae that have been treated with cement. The vertebral volume that is filled with cement can also range widely from partial to complete filling [ 12 ].…”