Biomechanical analysis of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body: a finite element study

Abstract

BackgroundTo compare the biomechanical properties of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body (HAVB) with the titanium mesh cage (TMC) and artificial vertebral body (AVB), and evaluate its biomechanical efficacy in spinal stability reconstruction.MethodsA 3D nonliner FE model of the intact L1-sacrum was established and validated. Three FE models which instrumented HAVB, TMC, and AVB were constructed for surgical simulation. A pure moment of 7.5 Nm and a 400-N preload were applied to the three FE models in 3D motion. The peak von Mises stress upon each prosthesis and the interfaced endplate was recorded for analysis. In addition, the overall and intersegmental range of motion (ROM) of each model was investigated to assess the efficacy of each model in spinal stability reconstruction.ResultsAVB had the greatest stress concentration compared with TMC and HAVB in all motions (25.6–101.8 times of HAVB, 0.8–8.1 times of TMC). The peak stress on HAVB was 3.1–10.3% of TMC and 1.6–3.9% of AVB. The maximum stress values on L2 caudal and L4 cranial endplates are different between the three FE models: 0.9–1.9, 1.3–12.1, and 31.3–117.9 times of the intact model on L2 caudal endplates and 0.9–3.5, 7.2–31.5, and 10.3–56.4 times of the intact model on L4 cranial endplates in HAVB, TMC, and AVB, respectively, while the overall and segmental ROM reduction was similar between the three models, with AVB providing a relatively higher ROM reduction in all loading conditions (88.1–84.7% of intact model for overall ROM and 69.5–82.1% for L1/2, 87.0–91.7% for L2/4, and 71.1–87.2% for L4/5, respectively).ConclusionsHAVB had similar biomechanical efficacy in spinal stability reconstruction as compared with TMC and AVB. The material used and the anatomic design of HAVB can help avoid stress concentration and the stress shielding effect, thus greatly reducing the implant-associated complications. HAVB exhibited some advantageous biomechanical properties over TMC and AVB and may prove to be a potentially viable option for spinal stability reconstruction. Further in vivo and vitro studies are still required to validate our findings and conclusions.

Efficacy of NHP66 Bioactive Cage on Patients with Cervical Spine Injury in Short-Track Speed Skating

“…However, the ilium, as a cancellous bone with thin cortical bone, has low strength and is prone to subsidence and collapse [ 22 ]. For STSS athletes, the strength of the cage is of particular importance for adaption to fierce sports confrontation [ 23 ]. Additionally, the integrity of lower limbs is crucial for STSS, as the sport requires strong explosive power of legs.…”

“…In light of the above reasons, AIB is not suitable for restoring CSI in STSS athletes. The cage for the anterior column of the spine must have favorable biocompatibility, high toughness, and mechanical properties, with the ability to effectively induce osteoblast activity and facilitate clinical examination [ 23 ]. NHP66 is an optimal material able to perfectly meet the above requirements.…”

Posterior unilateral approach with 270° spinal canal decompression and three-column reconstruction using double titanium mesh cage for thoracic and lumbar burst fractures

“…The anterior column supports approximately 80% of the axial load, and its efficiency for reconstruction is crucial ( 19 ). Biomechanical studies have indicated that TMC is resistant to axial compression ( 20 ). These cages are available in different diameters and heights, and the tamping of autografts inside the mesh can significantly promote osteoinduction.…”

A Comparison of Corpectomy ACDF Hybrid Procedures with Nano‐Hydroxyapatite/Polyamide 66 Cage and Titanium Mesh Cage for Multi‐level Degenerative Cervical Myelopathy: A Stepwise Propensity Score Matching Analysis

“…The titanium mesh cage (TMC) is limited by its high cage subsidence rates, radiolucent opacity, and increased stress shielding effect due to the elastic modulus 21–23 . The nano‐hydroxyapatite/polyamide‐66 (n‐HA/PA66) cage is a hollow bullet composed of a bionic composite material synthesized from nano‐hydroxyapatite and polar polymer polyamide‐66, which simulates the composition and biomechanical characteristics of natural bone 24,25 . Previous studies have found satisfactory clinical results with the n‐HA/PA66 cage to reconstruct the stability of the anterior cervical column 26–31 .…”