scholarly journals Biomechanical Evaluation of Different Surgical Approaches for the Treatment of Adjacent Segment Diseases After Primary Anterior Cervical Discectomy and Fusion: A Finite Element Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Wencan Ke ◽  
Chao Chen ◽  
Bingjin Wang ◽  
Wenbin Hua ◽  
Saideng Lu ◽  
...  
Keyword(s):  
Finite Element ◽  
Revision Surgery ◽  
Anterior Cervical Discectomy ◽  
Surgical Approaches ◽  
Adjacent Segment ◽  
Fe Model ◽  
Element Analysis ◽  
Cervical Discectomy ◽  
Computed Tomography Images ◽  
Adjacent Segments

Symptomatic adjacent segment disease (ASD) is a common challenge after anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the biomechanical effects of a second ACDF and laminoplasty for the treatment of ASD after primary ACDF. We developed a finite element (FE) model of the C2-T1 based on computed tomography images. The FE models of revision surgeries of ACDF and laminoplasty were simulated to treat one-level and two-level ASD after primary ACDF. The range of motion (ROM) and intradiscal pressure (IDP) of the adjacent segments, and stress in the cord were analyzed to investigate the biomechanical effects of the second ACDF and laminoplasty. The results indicated that revision surgery of one-level ACDF increased the ROM and IDP at the C2–C3 segment, whereas two-level ACDF significantly increased the ROM and IDP at the C2–C3 and C7-T1 segments. Furthermore, no significant changes in the ROM and IDP of the laminoplasty models were observed. The stress in the cord of the re-laminoplasty model decreased to some extent, which was higher than that of the re-ACDF model. In conclusion, both ACDF and laminoplasty can relieve the high level of stress in the spinal cord caused by ASD after primary ACDF, whereas ACDF can achieve better decompression effect. Revision surgery of the superior ACDF or the superior and inferior ACDF after the primary ACDF increased the ROM and IDP at the adjacent segments, which may be the reason for the high incidence of recurrent ASD after second ACDF.

scholarly journals Biomechanical Effect of Plate-to-Disc Distance on Surgical and Adjacent Segment in C5/C6 Anterior Cervical Discectomy and Fusion - A Finite Element Analysis

2020 ◽  
Author(s):  
Yuan Xue ◽  
Xing Guo ◽  
Jiaming Zhou ◽  
Yueyang Tian ◽  
Liang Kang
Keyword(s):  
Finite Element ◽  
Intervertebral Disc ◽  
Bone Graft ◽  
Anterior Cervical Discectomy ◽  
Von Mises Stress ◽  
Adjacent Segment ◽  
Titanium Plate ◽  
Cervical Discectomy ◽  
Cage Subsidence ◽  
Biomechanical Effect

Abstract Background: The PDD is an important factor affecting the degeneration of adjacent segments after ACDF. However, the most suitable PDD is controversial. This study examined the adjacent intervertebral disc stress, bone graft stress, titanium plate stress and screw stress to evaluate the biomechanical effect of different Plate-to-Disc Distance (PDD) on surgical segment and adjacent segment following C5/C6 anterior cervical discectomy and fusion (ACDF). Methods: We constructed 10 preoperative finite element models (FEM) of intact C4–C7 segments and validated them in the present study. We simulated ACDF surgery based on the 10 intact models in software. We designed three different distance of Plate-to-Disc titanium plates: L, long PDD (10 mm); S, short PDD (0 mm); and N, PDD (5 mm). The changes in C4/C5 and C6/C7 intervertebral disc stress, bone graft stress, titanium plate stress and screw stress were analyzed.Results: The von Mises stress of C4/C5 and C6/C7 intervertebral discs have no significant differences (P>0.05) in three different PDD groups. Titanium plate stress increased as the PDD decreased. The bone graft stress and screws stress decreased as the PDD decreased. The maximum stress of each part occurred was mostly in the conditions of rotation and lateral bending. Conclusions: The PDD has no effect on adjacent intervertebral disc stress, but it is an important factor that affecting the bone graft stress, titanium plate stress and screws stress after ACDF. Shorter PDD plate can provide better stability to reduce stress on screws and bone graft, that may be helpful to prevent cage subsidence, pseudarthrosis and instrument failure. This can serve as a reference for clinical choice of plate.

scholarly journals Comparative Analysis of the Biomechanical Characteristics After Different Minimally Invasive Surgeries for Cervical Spondylopathy: A Finite Element Analysis

2021 ◽  
Vol 9 ◽  
Author(s):  
Tao He ◽  
Jun Zhang ◽  
Tong Yu ◽  
Jiuping Wu ◽  
Tianyang Yuan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cervical Spine ◽  
Minimally Invasive ◽  
Element Analysis ◽  
Cervical Discectomy ◽  
Cervical Spondylotic Radiculopathy ◽  
Flexion Extension ◽  
Adjacent Segments ◽  
Cervical Foraminotomy

Minimally invasive surgeries, including posterior endoscopic cervical foraminotomy (PECF), microsurgical anterior cervical foraminotomy (MACF), anterior transdiscal approach of endoscopic cervical discectomy (ATd-ECD), and anterior transcorporeal approach of endoscopic cervical discectomy (ATc-ECD), have obtained positive results for cervical spondylotic radiculopathy. Nonetheless, there is a lack of comparison among them regarding their biomechanical performance. The purpose of this study is to investigate the biomechanical changes of operated and adjacent segments after minimally invasive surgeries compared to a normal cervical spine. A three-dimensional model of normal cervical vertebrae C3–C7 was established using finite element analysis. Afterwards, four surgical models (PECF, MACF, ATd-ECD, and ATc-ECD) were constructed on the basis of the normal model. Identical load conditions were applied to simulate flexion, extension, lateral bending, and axial rotation of the cervical spine. We calculated the range of motion (ROM), intradiscal pressure (IDP), annulus fibrosus pressure (AFP), uncovertebral joints contact pressure (CPRESS), and facet joints CPRESS under different motions. For all circumstances, ATc-ECD was close to the normal cervical spine model, whereas ATd-ECD significantly increased ROM and joints CPRESS and decreased IDP in the operated segment. PECF increased more the operated segment ROM than did the MACF, but the MACF obtained maximum IDP and AFP. Except for ATc-ECD, the other models increased joints CPRESS of the operated segment. For adjacent segments, ROM, IDP, and joints CPRESS showed a downward trend in all models. All models showed good biomechanical stability. With their combination biomechanics, safety, and conditions of application, PECF and ATc-ECD could be appropriate choices for cervical spondylotic radiculopathy.

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