scholarly journals Bicortical Screw Purchase at Upper Instrumented Vertebra (UIV) Can Cause UIV Fracture After Adult Spinal Deformity Surgery: A Finite Element Analysis Study

Neurospine ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 377-383 ◽  
Author(s):  
Seong-Hyun Wui ◽  
Seung-Jae Hyun ◽  
Bokku Kang ◽  
Ki-Jeong Kim ◽  
Tae-Ahn Jahng ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Spinal Deformity ◽  
Adult Spinal Deformity ◽  
Element Analysis ◽  
Analysis Study ◽  
Spinal Deformity Surgery ◽  
Upper Instrumented Vertebra ◽  
Bicortical Screw

scholarly journals Longer Screws Can Reduce the Stress on the Upper Instrumented Vertebra With Long Spinal Fusion Surgery: A Finite Element Analysis Study

2021 ◽  
pp. 219256822110184
Author(s):  
Shin Oe ◽  
Kengo Narita ◽  
Kazuhiro Hasegawa ◽  
Raghu N. Natarajan ◽  
Yu Yamato ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Adult Spinal Deformity ◽  
Equivalent Stress ◽  
Fe Model ◽  
Element Analysis ◽  
Analysis Study ◽  
Screw Insertion ◽  
Cord Injury ◽  
Upper Instrumented Vertebra

Study Design: A finite element analysis study. Objective: Of proximal junctional failure, upper instrumented vertebra (UIV) fracture can causes severe spinal cord injury. Previously, we reported that higher occupancy rate of pedicle screw (ORPS) at UIV prevented UIV fracture in adult spinal deformity surgery; we had not yet tested this finding using a biomechanical study. The purpose of present study was to measure the differences in loads on the UIV according to the length of PS and ORPS. Methods: We designed an FE model of a lumbar spine (L1-S1) using FE software. The PS was set from L2 to S1 and connected the rod. The FE model simulated flexion (8 Nm) to investigate the loads at UIV (L2) according to the length of the PS. There were 5 screw lengths examined: 40 (ORPS 36.4%), 45 (48.5%), 50 (66.7%), 55 (81.8%), and 60 mm (93.9%). Results: Stress with bending motion was likely to occur at the upper front edge of the vertebral body, the pedicles, and the screw insertion point. The maximum equivalent stress according to screw lengths of 40, 45, 50, 55, and 60 mm were 45.6, 37.2, 21.6, 13.3, and 14.8 MPa, respectively. The longer screw, the less stress was applied to UIV. No remarkable change was observed between the screw lengths of 55 and 60 mm. Conclusions: Increasing ORPS to 81.8% or more reduced the load on the UIV. To prevent UIV fracture, the PS length in the UIV should be more than ORPS 81.8%.

scholarly journals Morse taper performance: A finite element analysis study

Clinics ◽  
2019 ◽  
Vol 74 ◽  
Author(s):  
Gustavo Passarelli Petris ◽  
João Paulo De Carli ◽  
Luiz Renato Paranhos ◽  
Pâmela Letícia Santos ◽  
Paula Benetti ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
Analysis Study
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