Biomechanical Advantages of Novel Duet Screws Plus Bilateral Satellite Rods Fixation in the Correction Surgery for Adult Spinal Deformity

作者：He Zhong, Yi Chen, Zhen Liu, Bo Kyu Yang, Benlong Shi, Yu Wang, Zhenhua Feng, Tianyuan Zhang, Xipu Chen, Yong Qiu, Xiaodong Qin, Zezhang Zhu · 发表于：Orthopaedic Surgery · 年份：2025 · DOI：10.1111/os.70121 · 被引用次数：2 · 研究领域：Scoliosis diagnosis and treatment、Spine and Intervertebral Disc Pathology、Spinal Fractures and Fixation Techniques

PURPOSE: Adult spinal deformity (ASD) patients undergoing pedicle subtraction osteotomy (PSO) with long fusion to the pelvis have a high risk of rod failure at the PSO level or adjacent areas. This study aimed to investigate the biomechanical advantages of novel duet screws (multiaxial screws with dual heads) plus satellite rods in ASD correction using finite element models and cadaveric specimens. METHODS: A lumbar-pelvis finite element model was constructed, and Von Mises equivalent stress was used to analyze the structural stress under different fixation constructs. Six human cadaveric spine segments (T11-S2) were selected to validate the finite element results. L3 PSO was performed, with posterior fixation from L1 to pelvis using S2-alar-iliac (S2AI) screws, and satellite rods (L2-L4) were connected to the primary rods using duet screws. Three fixation constructs were evaluated: two rods (Group A), three rods (Group B), and four rods (Group C). In Group B, a biomechanical test was performed on two sides: single rod side (Group B-S) and double rods side (Group B-D). In vitro motion tests were performed under pure moments in lateral bending (LB), flexion/extension (FE), and axial rotation (AR) to measure the range of motion. Rod strain was measured at L3 and S2. RESULTS: Finite element analysis revealed stress concentration near the PSO site, the screw bases, and the L5-S1 region. The use of duet screws with satellite rods significantly reduced primary rod stress. Cadaveric...