Biomechanical comparison of a novel transoral atlantoaxial anchored cage with established fixation technique - a finite element analysis

Abstract

BackgroundThe transoral atlantoaxial reduction plate (TARP) fixation has been introduced to achieve reduction, decompression, fixation and fusion of C1–C2 through a transoral-only approach. However, it may also be associated with potential disadvantages, including dysphagia and load shielding of the bone graft. To prevent potential disadvantages related to TARP fixation, a novel transoral atlantoaxial fusion cage with integrated plate (Cage + Plate) device for stabilization of the C1-C2 segment is designed. The aims of the present study were to compare the biomechanical differences between Cage + Plate device and Cage + TARP device for the treatment of basilar invagination (BI) with irreducible atlantoaxial dislocation (IAAD).MethodsA detailed, nonlinear finite element model (FEM) of the intact upper cervical spine had been developed and validated. Then a FEM of an unstable BI model treated with Cage + Plate fixation, was compared to that with Cage + TARP fixation. All models were subjected to vertical load with pure moments in flexion, extension, lateral bending and axial rotation. Range of motion (ROM) of C1-C2 segment and maximum von Mises Stress of the C2 endplate and bone graft were quantified for the two devices.ResultsBoth devices significantly reduced ROM compared with the intact state. In comparison with the Cage + Plate model, the Cage + TARP model reduced the ROM by 82.5 %, 46.2 %, 10.0 % and 74.3 % in flexion, extension, lateral bending, and axial rotation. The Cage + Plate model showed a higher increase stresses on C2 endplate and bone graft than the Cage + TARP model in all motions.ConclusionsOur results indicate that the novel Cage + Plate device may provide lower biomechanical stability than the Cage + TARP device in flexion, extension, and axial rotation, however, it may reduce stress shielding of the bone graft for successful fusion and minimize the risk of postoperative dysphagia. Clinical trials are now required to validate the reproducibility and advantages of our findings using this anchored cage for the treatment of BI with IAAD.

Biomechanical Evaluation of a New Fixation Type in 3D-Printed Periacetabular Implants using a Finite Element Simulation

“…These fixation types reportedly incur high traumatic fracture risks under compressive loading conditions [16,17]. Enhancements of the mechanical stability using spinal rod connectors, which have a bridge component between two straight connectors, have been reported in spine surgery publications [18,19]. Thus far, this bridge component design has not been utilized for pelvic implant fixation.…”

Retropharyngeal Reduction Plate for Treatment of Irreducible Atlantoaxial Dislocation: A Cadaveric Test and Finite Element Analysis

“…The stress tolerance of the two internal xations are consistent in exion, extension, bending, and rotation. In addition, the mean stress of the two internal xations was far below the maximum yield strength (795-827 MPa) and ultimate strength (860-896 MPa) of titanium alloy [14].…”

Anterior stabilization of C1–C4 vertebrae after transoral removal of a giant cell tumor of C2–C3 vertebrae

“…Из-за анатомических особенностей и технической сложности вмешательств на верхнешейных отделах позвоночника в настоящее время нет стандартной хирургической техники лечения гигантоклеточной опухоли шейного отдела позвоночника, особенно в C 1 и C 2 позвонках. Традиционно хирургическое лечение таких образований включает широкую (en-bloc) резекцию, внутриклеточный кюретаж [30,31] и лучевую терапию [32]. Наиболее часто использующейся стабилизирующей операцией при резекции С 2 позвонка является окципитоспондилодез.…”

“…Впервые передняя стабилизация атлантоаксиального сочленения была описана Schmelzle et al [36] в 1987 г. В ходе биомеханических и клинических исследований выявлено, что передняя стабилизация является надежной [30,[37][38][39]. Однако из-за обнаружения недостатка пластины Harms в виде высокой частоты раскручивания винтов [37,39] ее применение на тот момент было ограничено.…”

“…В настоящее время одной из самых распространенных систем передней стабилизации является Transoral atlantoaxial reduction plate. Также известна система Transoral atlantoaxial anchored cage [30].…”