The Effects of a Semiconstrained Integrated Artificial Disc on Zygapophyseal Joint Pressure and Displacement

Yao, Qingqiang; Wang, Jeffrey C.; Shamie, Arya Nick; Lord, Elizabeth L.; Cohen, Yermie; Zheng, Shengnai; Wei, Bo; Guo, Yang; Hu, Wenhao; Yan, Junwei; Zhang, Dongsheng; Wang, Liming

doi:10.1097/brs.0000000000000638

Cited by 5 publications

(6 citation statements)

References 29 publications

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“…The studies were carried at 22 - 23 °C, with an environmental humidity of 40%. To prevent unwanted desiccation we sprayed the specimens with 0.9% sodium chloride solution at least every five minutes [46 , 72 , 107 , 111] .…”

Section: Methodsmentioning

confidence: 99%

“…Traditionally, total disc implant designs have had a ball and socket mechanism [16] , which can be constrained, unconstrained or semi-constrained [111] . These lumbar prostheses do not replicate the features of the intact lumbar disc, particularly in what pertains to the Instantaneous centre of rotation (ICR).…”

Section: Introductionmentioning

confidence: 99%

“…Hence, although movement is allowed, it is not within the normal ranges. This is particularly true in the case of 3-piece prostheses where the central portion is oftentimes mobile, compared to 2-piece disc replacements [111] . The characteristics often dictate abnormal patterns of translation and rotation, and different ICR distribution than the intact lumbar disc [65] .…”

Section: Introductionmentioning

confidence: 99%

“…The characteristics often dictate abnormal patterns of translation and rotation, and different ICR distribution than the intact lumbar disc [65] . The most challenging motion is axial rotation, where excess movement has to be controlled by zygapophyseal joints, unless the implant has some ligament-like components that limit the range of movement (ROM) in this direction [85 , 111] .…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the commercially available lumbar disc prostheses do not accommodate to the natural ICR [80 , 87 , 111] . This results in an overload of adjacent anatomical structures, particularly the zygapophyseal joints [12 , 42 , 79 , 86 , 88 ].…”

Section: Introductionmentioning

confidence: 99%

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ICR in human cadaveric specimens: An essential parameter to consider in a new lumbar disc prosthesis design

Vanaclocha¹,

Atienza

Vanaclocha

et al. 2020

North American Spine Society Journal (NASSJ)

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Study design: Biomechanical study in cadaveric specimens. Background:The commercially available lumbar disc prostheses do not reproduce the intact disc's Instantaneous centre of Rotation (ICR), thus inducing an overload on adjacent anatomical structures, promoting secondary degeneration.Aim: To examine biomechanical testing of cadaveric lumbar spine specimens in order to evaluate and define the ICR of intact lumbar discs.Material and Methods: Twelve cold preserved fresh human cadaveric lumbosacral spine specimens were subjected to computerized tomography (CT), magnetic resonance imaging (MRI) and biomechanical testing. Kinematic studies were performed to analyse range of movements in order to determine ICR.Results: Flexoextension and lateral bending tests showed a positive linear correlation between the angle rotated and the displacement of the ICR in different axes.Discussion: ICR has not been taken into account in any of the available literature regarding lumbar disc prosthesis. Considering our results, neither the actual ball-and-socket nor the withdrawn elastomeric nucleus models fit the biomechanics of the lumbar spine, which could at least in part explain the failure rates of the implants in terms of postoperative failed back syndrome (low back pain). It is reasonable to consider then that an implant should also adapt the equations of the movement of the intact ICR of the joint to the post-surgical ICR.Conclusions: This is the first cadaveric study on the ICR of the human lumbar spine. We have shown that it is feasible to calculate and consider this parameter in order to design future prosthesis with improved clinical and biomechanical characteristics. * Corresponding author.spine [78] . When the intervertebral disc degenerates, it loses its capacity to transmit this load and thus may become a source of low back pain [66] .Lumbar disc arthroplasty was introduced in 1960 [27] , although results were not promising until the 1980 ′ s [7 , 36 , 60 , 115] . The aim of this surgical procedure is to preserve motion as well as to avoid spinal fusion related complications and side-effects. The first successfully implanted device was the SB Charitè [7 , 15] . The initial suboptimal results, which occurred due to mechanical failure [7 , 19 , 52 , 101 , 102] , were mitigated by repeatedly improving on the design [60] . Ever since, many other disc

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%