New Posterior Atlantoaxial Restricted Non-Fusion Fixation for Atlantoaxial Instability

Chen, Jinshui; Zhou, Fang; Ni, Bin; Guo, Qunfeng; Guan, Huapeng; Xu, Tianming; Liu, Qi

doi:10.1227/neu.0000000000001122

Cited by 9 publications

(9 citation statements)

References 23 publications

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“…Kato et al 12 designed a novel motion preservation device that preserves 50% of the motion at C1-2; however, the extremely large size of the device caused several problems. Chen et al 5 designed a posterior C1-2 restricted nonfusion fixation device that retains C1-2 rotation and lateral flexion motion but cannot preserve flexion-extension. Gradual improvements in anterior and posterior artificial joints have largely facilitated the preservation of ROM in the C1-2 joint in all directions.…”

Section: Discussionmentioning

confidence: 99%

Novel posterior artificial atlanto-odontoid joint for atlantoaxial instability: a biomechanical study

Shen

Deng

Yang

et al. 2018

Journal of Neurosurgery: Spine

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OBJECTIVEAtlantoaxial instability is usually corrected by anterior and/or posterior C1–2 fusion. However, fusion can lead to considerable loss of movement at the C1–2 level, which can adversely impact a patient’s quality of life. In this study, the authors investigated the stability and function of a novel posterior artificial atlanto-odontoid joint (NPAAJ) by using cadaveric cervical spines.METHODSThe Oc–C7 regions from 10 cadaveric spines were used for anteroposterior (AP) translation and range of motion (ROM) tests while intact and after destabilization, NPAAJ implantation, and double-rod fixation.RESULTSThe mean AP C1–2 translational distances in the intact, destabilization, and double-rod groups were 6.53 ± 1.07 mm, 11.54 ± 1.59 mm, and 3.24 ± 0.99 mm, respectively, and the AP translational distance in the NPAAJ group was significantly different from that in the intact group (p < 0.05). The AP translational distance in the NPAAJ group was not significantly different from that in the double-rod group (p = 0.24). The mean flexion, extension, and axial rotation ROM values of the NPAAJ group were 9.87° ± 0.91°, 8.75° ± 0.99°, and 61.93° ± 2.93°, respectively, and these were lower than the corresponding values in the intact group (p < 0.05). The mean lateral bending ROM in the NPAAJ group (9.26° ± 0.86°) was not significantly different from that in the intact group (p = 0.23), and the flexion, extension, and rotation ranges in the NPAAJ group were 79.5%, 85.2%, and 82.3%, respectively, of those in the intact group.CONCLUSIONSUse of NPAAJ for correction of atlantoaxial instability disorders caused by congenital odontoid dysplasia, odontoid fracture nonunion, and C-1 transverse ligament disruption (IA, IB, and IIB) may restore the stability and preserve most of the ROM of C1–2. Additionally, the NPAAJ may prevent soft tissue from embedding within the joint. However, additional studies should be performed before the NPAAJ is used clinically.

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Section: Discussionmentioning

confidence: 99%

Novel posterior artificial atlanto-odontoid joint for atlantoaxial instability: a biomechanical study

Shen

Deng

Yang

et al. 2018

Journal of Neurosurgery: Spine

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“…Recently, few attempts have been made to overcome this problem, by innovations of artificial C1-C2 joints. [ 9 10 11 12 13 14 15 ] These strive to restore CVJ stability and simultaneously preserve the C1-C2 movements as close to that seen in a nondiseased spine. For this purpose, an atlanto-odontoid joint prosthesis has been described, and was inserted in cadaveric specimens through a trans-oral approach.…”

Section: Discussionmentioning

confidence: 99%

“…[ 12 ] Similarly, another posterior C1-C2 restricted nonfusion fixation device consisting of multi-axial fixed connector with atlas-axis connecting rod systems, and preserving the rotation and lateral bending movements has been developed by Chen et al . [ 13 ] The above mentioned posterior motion-preserving prostheses can be useful in indications such as nonunion of dens fractures and injuries involving transverse ligament disruption. Nevertheless, these may not be appropriate for congenital AAD patients in whom the primary pathology lies in the lateral facetal joints.…”

Section: Discussionmentioning

confidence: 99%

C1-C2 arthroplasty for craniovertebral junction instability: A preliminary proof of concept in human cadavers

Karthigeyan

Salunke

Kodigudla

et al. 2022

J Craniovert Jun Spine

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Background: The atlantoaxial complex contributes to significant neck movements, especially the axial rotation. Its instability is currently treated with various C1-C2 fusion techniques. This however, considerably hampers the neck movements and affects the quality of life; a C1-C2 motion preserving arthroplasty could potentially overcome this drawback. Objectives: We evaluate the range of motion (ROM) of lateral C1-C2 artificial joints in cadaveric models. Materials and Methods: This is an in vitro cadaveric biomechanical study. After C1-C2 arthroplasty through a posterior approach, the C1-C2 ROM was tested in 4 fresh-frozen human cadaveric specimens, before and after destabilization. Results: The mean axial rotation demonstrated after the placement of C1-C2 joint implants was 15.46 degrees on the right and 16.03 degrees on the left side; the prosthesis provided stability, with 46% of the baseline C1-C2 axial rotation on either side. The ROM achieved in the other axes was less compared with that of intact specimens. To initiate rotation, a higher moment of 1.5 Nm was required in the presence of joint implants compared to 0.5 NM in unimplanted specimens. Conclusions: In our preliminary ROM evaluation, the C1-C2 arthroplasty appears to be stable and provides about half of the range of atlantoaxial rotation. It has the potential for joint motion preservation in the treatment of atlantoaxial instability resulting from lateral C1-C2 joint pathologies.

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“…We then orderly Fig. 1 All specimens were confirmed, by CT and X-ray, to be without fractures, deformities or any metastatic disease broke the ligaments of the atlantoaxial and eliminated the latter half of the lateral joint capsule [8]. An experimental model of atlantoaxial instability was constructed.…”

Section: Fixation and Test Sequencementioning

confidence: 99%

A biomechanical comparison of crossed and parallel rod configurations in atlantoaxial internal fixation

Feng¹,

Zou

Xu³

et al. 2020

Eur Spine J

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Background Posterior atlantoaxial fixation with screw rod forms an approximate "II" shape or "H" increasing transverse link for better stability. In order to improve stability and in consideration of difficult placement of transverse connecting rod, possibility of inadequate bone graft, some scholars have preliminarily researched biomechanics of a novel crossed rod as an approximate "X" configuration of screw rod. Purpose The aim of this study was to evaluate and compare the biomechanics of the crossed and parallel rod configurations in the screw rod system for posterior atlantoaxial fixation on a cadaveric model. Methods Six fresh cervical specimens were used to complete the range of motion (ROM) testing by applying pure moments of ± 2.0 nm. Following intact state and under destabilization testing, screws were implanted. The specimens were then tested in the following sequence: Group BLS + PR (C2 bilateral laminar screws + parallel rod), Group BLS + CR (C2 bilateral laminar screws + crossed rod), LPRLS + PR (C2 left pedicle screw and right laminar screw + parallel rod), LPRLS + CR (C2 left pedicle screw and right laminar screw + crossed rod), BPS + PR (C2 bilateral pedicle screws + parallel rod) and BPS + CR (C2 bilateral pedicle screws + crossed rod). The ROM of the C1-2 segments was measured in flexion-extension, lateral bending and axial rotation. Six surgical constructs were compared between the groups and with intact condition, respectively. Results The six fixed modes significantly increased stability compared with both the intact and destabilization group in flexion-extension, lateral bending and axial rotation (p < .05). In extension, BPS + CR and BLS + CR showed greater stability than BLS + PR (p < .05). During flexion, the six fixation methods showed no statistical significance (p > .05). In left lateral bending, stability of the other five screw rod fixation techniques significantly increased when compared with BLS + PR (p < .05). In the right lateral bending direction, the stability of BLS + PR was worse than that of BPS + CR and BPS + PR (p < .05). In the left axial rotation, stability of BLS + CR, LPRLS + CR and BPS + CR was greater than that of BLS + PR, LPRLS + PR and BPS + PR (p < .05). In the right axial rotation, the stability of BPS + CR and BLS + CR was greater than that of BLS + PR (p < .05). ConclusionThe six investigated fixation methods provide sufficient biomechanical stability. The crossed rod configuration can further enhance the axial rotation stability of the screw rod system, which consists of C1 bilateral pedicle and C2 pedicle, or C2 lamina screws. The crossed rod can also improve the stability of the screw rod system made up of C1 bilateral pedicle and C2 lamina screws in lateral bending and extension. The crossed rod configuration is reliable and provides superior stability for clinical application.

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New Posterior Atlantoaxial Restricted Non-Fusion Fixation for Atlantoaxial Instability

Cited by 9 publications

References 23 publications

Novel posterior artificial atlanto-odontoid joint for atlantoaxial instability: a biomechanical study

Novel posterior artificial atlanto-odontoid joint for atlantoaxial instability: a biomechanical study

C1-C2 arthroplasty for craniovertebral junction instability: A preliminary proof of concept in human cadavers

A biomechanical comparison of crossed and parallel rod configurations in atlantoaxial internal fixation

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