Impact of Cervical Artificial Disc Implantation on the Biomechanical Function of Adjacent Segments

2013 ◽  
Vol 748 ◽  
pp. 358-364
Author(s):  
Wen Zhi Zhao ◽  
Bin Li ◽  
Bing Zhi Chen ◽  
Sheng Wei He ◽  
Jin Su ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Intervertebral Disc ◽  
Interbody Fusion ◽  
Element Model ◽  
Cervical Disc ◽  
Adjacent Segment ◽  
Artificial Disc ◽  
Range Of Movement ◽  
Fusion Surgery ◽  
Adjacent Segments

The range of movement(ROM) of adjacent segments and the change of intervertebral disc stress after implanting artificial cervical disc are investigated. The contact problem for bio-modeling is introduced. A normal cervical spine finite element model is proposed. The bone graft and fusion between C5 and C6 and C5/6 artificial disc implantation were simulated. The range of movement on adjacent segment and the change of intervertebral disc’s stress in such two cases are analyzed. Computational results show that the model includes the ligaments, joint capsule and other soft tissue structures, which is real, fine and high accuracy. When the adjacent intervertebral ROM was increased after interbody fusion surgery, the stress of corresponding intervertebral disc was increased obviously and the stress of upper segment of nucleus pulposus and annulus fibrosus were also increased about 70% ,besides the next-bit segments was increased about 40%. There were no differences among cervical spine ROM except extension (p> 0.05) after the implantation of artificial disc, and the stress on adjacent segments was increased less than 10%. The implantation of artificial cervical disc can release the stress on adjacent segments in a certain extent, and resume cervical activities at the same time.

A Computer Simulation Study of Fusion Surgery and Artificial Disc Replacement on the Human Cervical Spine

2006 ◽  
Vol 326-328 ◽  
pp. 903-906
Author(s):  
Hyung Soo Ahn ◽  
Il Hyung Park ◽  
Denis DiAngelo
Keyword(s):  
Cervical Spine ◽  
Adjacent Segment ◽  
Artificial Disc ◽  
Spherical Joint ◽  
Rotational Stiffness ◽  
Computer Simulation Study ◽  
Fusion Surgery ◽  
Biomechanical Changes ◽  
Disc Level ◽  
Flexion And Extension

The biomechanical changes brought on by spine fusion and the artificial disc designs to restore physiologic motion were studied by using a cervical spine computer model. Fusion increased the motion compensation at the adjacent segment during flexion and extension. The global rotational stiffness and segmental disc forces were also increased after fusion. Among the three prosthetic disc designs, the PDD-III (5-DOF spherical joint in plane parallel with the C5-C6 disc level) maintained the normal motion and minimized load build up of adjacent segment.

Artificial Disc Versus Fusion: Effect on Three-Dimensional Dynamic In Vivo Cervical Spine Motion

2011 ◽  
Author(s):  
Colin P. McDonald ◽  
Michael J. McDonald ◽  
Nicole L. Ramo ◽  
Stephen W. Bartol ◽  
Michael J. Bey
Keyword(s):  
Cervical Spine ◽  
Three Dimensional ◽  
Adjacent Segment Degeneration ◽  
Cervical Disc ◽  
Adjacent Segment ◽  
Artificial Disc ◽  
Disc Disease ◽  
Adjacent Disc ◽  
Spine Motion

Intervertebral disc degeneration in the cervical spine is a common condition that often manifests as cervical disc disease, resulting in pain, motor weakness and sensory deficits. The most common surgical treatment strategy involves removal of the diseased disc and fusion of the adjacent vertebrae. Although fusion typically relieves symptoms at the surgical site, evidence of degeneration in the adjacent disc has been reported in 25–92% of patients [1,2]. It has been hypothesized that the progression of adjacent segment degeneration is a result of increased motion at the segments adjacent to the site of fusion [3]. As a response to this proposed mechanism of degeneration, artificial discs were designed with the goals of preserving motion at the operative site and maintaining normal motion in the adjacent segments. However, the extent to which normal adjacent segment motion is maintained in artificial disc patients compared to fusion patients remains unknown. Thus, the objective of this study was to compare the dynamic, three-dimensional (3D) motion of the cervical spine in fusion patients and artificial disc replacement patients.

scholarly journals Hybrid Strategy of Cervical Artificial Disc and Intervertebral Cage – Biomechanical Effects on the Adjacent Tissues and Implants

2020 ◽  
Author(s):  
Tzu-Tsao Chung ◽  
Dueng-Yuan Hueng ◽  
Chi-Pin Hsu ◽  
Chun-Ming Chen ◽  
Shang-Chih Lin
Keyword(s):  
Element Model ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Peek Cage ◽  
Artificial Disc ◽  
Hybrid Surgery ◽  
Hybrid Strategy ◽  
Intervertebral Cage ◽  
Adjacent Segments ◽  
Nonlinear Finite Element Model

Abstract Background: Adjacent segment degeneration (ASD) is a concern in multi-level ACDF surgery. Hybrid surgery with C-ADR and ACDF are an alternative treatment to reduce the level of increased rigidity, but biomechanical differences between strategies using one C-ADR and two ACDFs have not been thoroughly investigated.Methods: To evaluate the placement-related effects of using one cervical artificial disc replacement (C-ADR) and two anterior cervical discectomy and fusion (ACDF) on tissue responses and implant behavior. A nonlinear finite element model from the C2 to the T1 vertebrae was developed. Ligament interconnection, follower loads, and weight compression were used to simulate cervical flexion. Within the C4-C7 segments, two placements of one C-ADR and two ACDFs were arranged: PAP (peek cage, artificial disc, and peek cage) and APP.Results: Both PAP and APP consistently induced kinematic and mechanical redistribution to adjacent segments. The C-ADR served as a buffer of the compensated motion and stress from the ACDF segments. The motion and stress of the cranial C2-C3 and C3-C4 segments were greater for the PAP than the APP constructs. However, the caudal C7-T1 segment of the APP construct was more flexed and stressed. Serially stacked cages of the APP placement increased bone-cage stresses, potentially inducing subsidence and loosening. The sandwiched C-ADR of the PAP construct accommodated the compensated motion and stress from the adjacent ACDFs more than the APP construct.Conclusions: The PAP and APP placements cause more severe ASD progression at the cranial and caudal segments, respectively. The PAP placement is preferred for concerns regarding ACDF and postoperative degeneration of caudal segments. The APP placement is recommended when C-ADR failure and ASD progression are considered.

scholarly journals History of cervical disc arthroplasty

2009 ◽  
Vol 27 (3) ◽  
pp. E10 ◽  
Author(s):  
Ali A. Baaj ◽  
Juan S. Uribe ◽  
Fernando L. Vale ◽  
Mark C. Preul ◽  
Neil R. Crawford
Keyword(s):  
Cervical Spine ◽  
Load Transfer ◽  
The Other ◽  
Cervical Disc ◽  
Cervical Disc Arthroplasty ◽  
Adjacent Segment ◽  
Cervical Arthroplasty ◽  
Disc Arthroplasty ◽  
History Of ◽  
Adjacent Segments

Enthusiasm for cervical disc arthroplasty is based on the premise that motion-preserving devices attenuate the progression of adjacent-segment disease (ASD) in the cervical spine. Arthrodesis, on the other hand, results in abnormal load transfer on adjacent segments, leading to the acceleration of ASD. It has taken several decades of pioneering work to produce clinically relevant devices that mimic the kinematics of the intervertebral disc. The goal of this work is to trace the origins of cervical arthroplasty technology and highlight the attributes of devices currently available in the market.

scholarly journals Comparison of pedicle screw–based dynamic stabilization and fusion surgery in the treatment of radiographic adjacent-segment degeneration: a retrospective analysis of single L5–S1 degenerative spondylosis covering 4 years

2016 ◽  
Vol 25 (6) ◽  
pp. 706-712 ◽  
Author(s):  
Yu Han ◽  
Jianguang Sun ◽  
Chenghan Luo ◽  
Shilei Huang ◽  
Liren Li ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Interbody Fusion ◽  
Posterior Lumbar Interbody Fusion ◽  
Adjacent Segment Degeneration ◽  
Adjacent Segment ◽  
Spinopelvic Parameters ◽  
Fusion Surgery ◽  
Spinal Stabilization ◽  
Pfirrmann Grade

OBJECTIVE Pedicle screw–based dynamic spinal stabilization systems (PDSs) were devised to decrease, theoretically, the risk of long-term complications such as adjacent-segment degeneration (ASD) after lumbar fusion surgery. However, to date, there have been few studies that fully proved that a PDS can reduce the risk of ASD. The purpose of this study was to examine whether a PDS can influence the incidence of ASD and to discuss the surgical coping strategy for L5–S1 segmental spondylosis with preexisting L4–5 degeneration with no related symptoms or signs. METHODS This study retrospectively compared 62 cases of L5–S1 segmental spondylosis in patients who underwent posterior lumbar interbody fusion (n = 31) or K-Rod dynamic stabilization (n = 31) with a minimum of 4 years' follow-up. The authors measured the intervertebral heights and spinopelvic parameters on standing lateral radiographs and evaluated preexisting ASD on preoperative MR images using the modified Pfirrmann grading system. Radiographic ASD was evaluated according to the results of radiography during follow-up. RESULTS All 62 patients achieved remission of their neurological symptoms without surgical complications. The Kaplan-Meier curve and Cox proportional-hazards model showed no statistically significant differences between the 2 surgical groups in the incidence of radiographic ASD (p > 0.05). In contrast, the incidence of radiographic ASD was 8.75 times (95% CI 1.955–39.140; p = 0.005) higher in the patients with a preoperative modified Pfirrmann grade higher than 3 than it was in patients with a modified Pfirrmann grade of 3 or lower. In addition, no statistical significance was found for other risk factors such as age, sex, and spinopelvic parameters. CONCLUSIONS Pedicle screw–based dynamic spinal stabilization systems were not found to be superior to posterior lumbar interbody fusion in preventing radiographic ASD (L4–5) during the midterm follow-up. Preexisting ASD with a modified Pfirrmann grade higher than 3 was a risk factor for radiographic ASD. In the treatment of degenerative diseases of the lumbosacral spine, the authors found that both of these methods are feasible. Also, the authors believe that no extra treatment, other than observation, is needed for preexisting degeneration in L4–5 without any clinical symptoms or signs.

scholarly journals A lattice topology optimization of cervical interbody fusion cage and finite element comparison with ZK60 and Ti-6Al-4V cages

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Jun Sun ◽  
Qiuan Wang ◽  
Dazhao Cai ◽  
Wenxiang Gu ◽  
Yiming Ma ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Topology Optimization ◽  
Bone Graft ◽  
Interbody Fusion ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Cervical Disc ◽  
Significant Difference ◽  
Fusion Cage

Abstract Background In current clinical practice, the most commonly used fusion cage materials are titanium (Ti) alloys. However, titanium alloys are non-degradable and may cause stress shielding. ZK60 is a bio-absorbable implant that can effectively avoid long-term complications, such as stress shielding effects, implant displacement, and foreign body reactions. In this study, we aimed at investigating the biomechanical behavior of the cervical spine after implanting different interbody fusion cages. Methods The finite element (FE) models of anterior cervical disc removal and bone graft fusion (ACDF) with a ZK60 cage and a Ti cage were constructed, respectively. Simulations were performed to evaluate their properties of flexion, extension, lateral bending, and axial rotation of the cervical spine. Moreover, a side-by-side comparison was conducted on the range of motion (ROM), the deformation of cages, the stress in the cages, bone grafts, and cage-end plate interface. Simultaneously, according to the biomechanical analysis results, the microporous structure of the ZK60 cage was improved by the lattice topology optimization technology and validation using static structure. Results The ROMs in the current study were comparable with the results reported in the literature. There was no significant difference in the deformation of the two cages under various conditions. Moreover, the maximum stress occurred at the rear of the cage in all cases. The cage’s and endplate-cage interface’s stress of the ZK60 group was reduced compared with the Ti cage, while the bone graft stress in the ZK60 fusion cage was significantly greater than that in the Ti fusion cage (average 27.70%). We further optimized the cage by filling it with lattice structures, the volume was decreased by 40%, and validation showed more significant biomechanical properties than ZK60 and Ti cages. Conclusion The application of the ZK60 cage can significantly increase the stress stimulation to the bone graft by reducing the stress shielding effect between the two instrumented bodies. We also observed that the stress of the endplate-cage interface decreased as the reduction of the cage’s stiffness, indicating that subsidence is less likely to occur in the cage with lower stiffness. Moreover, we successfully designed a porous cage based on the biomechanical load by lattice optimization.

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