Design a novel integrated screw for minimally invasive atlantoaxial anterior transarticular screw fixation: a finite element analysis

Abstract

Purpose: To design a new type of screw for minimally invasive atlantoaxial anterior transarticular screw (AATS) fixation with a diameter that is significantly thicker than that of traditional screws, threaded structures at both ends, and a porous metal structure in the middle. The use of a porous metal structure can effectively promote bone fusion and compensate for the disadvantages of traditional AATSs in terms of insufficient fixation strength and difficulty of bone fusion. The biomechanical stability of this screw was verified through finite element analysis. This instrument may provide a new surgical option for the treatment of atlantoaxial disorders. Methods: According to the surgical procedure, the new type of AATS was placed in a three-dimensional atlantoaxial model to determine the setting of relevant parameters such as the diameter, length, and thread to porous metal ratio of the structure. According to the results of measurement, the feasibility and safety of the new AATS were verified, and a representative finite element model of the upper cervical vertebrae was chosen to establish, and the validity of the model was verified. Then, finite element-based biomechanical analysis was performed using three models, i.e., atlantoaxial posterior pedicle screw fixation, traditional atlantoaxial AATS fixation, and atlantoaxial AATS fixation with the new type of screw, and the biomechanical effectiveness of the novel AATS was verified.

Biomechanical behaviour of tension-band-reconstruction titanium plate in open-door laminoplasty: a study based on finite element analysis

“…2 ). The cortical bone, facet joint surface and cartilage endplate were meshed by shell elements, with thickness of 1.5 mm, 0.2 mm and 0.4 mm [ 14 ], respectively. The intervertebral disc was divided into the nucleus pulposus and the annulus fibrosus, with the nucleus pulposus accounting for 1/3 of the intervertebral volume [ 15 ].…”

Biomechanical properties of different anterior and posterior techniques for atlantoaxial fixation: a finite element analysis

“…Currently, studies have demonstrated that posterior surgery represented by C1 lateral mass-C2 pedicle screw fixation achieves reliable stability and has high fusion rates and excellent clinical outcomes, so it has become the commonly used method for atlantoaxial fixation [ 6 – 8 ]. However, the posterior approach may present unsatisfactory decompression and reduction results in some cases in addition to the risk of vertebral artery injury and causing more extensive soft tissue damage than the anterior approach [ 9 , 10 ]. In particular, the anterior approach is suitable for patients with a vertebral artery with an abnormal course and patients with no posterior bony structure [ 11 ].…”

Biomechanical Properties of Novel Lateral Hole Pedicle Screws and Solid Pedicle Screws: A Comparative Study in the Beagle Dogs

“…They discovered that the bone tissue could not just bind at the interface of the implant but also grow through the lateral holes into the interior of the implant, where it tightly bound with the internal sidewalls of the implant, achieving secondary reinforcement and promoting bone fusion. Zhang et al 21 designed a novel atlantoaxial anterior transarticular screw with enlarged thread structures at both ends and a porous cylinder in the middle. The finite element analysis confirmed that the novel screw could provide improved biomechanical stability.…”

“…Zhang et al . 21 designed a novel atlantoaxial anterior transarticular screw with enlarged thread structures at both ends and a porous cylinder in the middle. The finite element analysis confirmed that the novel screw could provide improved biomechanical stability.…”