Effect of arthroplasty design on cervical spine kinematics: analysis of the Bryan Disc, ProDisc-C, and Synergy Disc

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Cervical total disc replacement has emerged as a surgical option to preserve motion and potentially avoid adjacent-segment disease after anterior cervical discectomy and fusion. Recently, much attention has been directed at the ability of a given device to maintain and/or restore normal segmental alignment. Nonphysiological disc and segmental angulation could result in increased stresses transmitted to the facet joints and posterior elements, conflicting with the essence of arthroplasty and potentially leading to adjacent-segment disease. The goal of this study was to contrast device alignment and segmental kinematics provided by 3 different cervical disc prostheses.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Sixty patients were retrospectively analyzed and divided into 3 groups receiving the Bryan, ProDisc-C, or Synergy disc. Only single-level arthroplasty cases were included in the study. Lateral dynamic radiographs of the cervical spine were analyzed using quantitative motion analysis software (Medical Metrics, Inc.) to analyze the kinematics at the index level both preoperatively and postoperatively. Several parameters were noted, including range of motion, disc angles, shell angles, anterior and posterior disc heights, translation, and center of rotation. Preoperative and postoperative data were compared using the Student t-test with a significance level of p &lt; 0.05.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Postoperatively, all 3 disc groups maintained adequate range of motion at the implanted level. With respect to the shell angles, the Synergy disc demonstrated the least variability, maintaining 6° lordotic configuration between the device endplates. In the Bryan disc group, significant shell kyphosis developed postoperatively (p &lt; 0.0001). Both ProDisc-C and Synergy discs significantly increased anterior and posterior disc heights (p &lt; 0.0001). The Bryan and Synergy discs maintained the natural center of rotation, whereas significant anterior shift occurred with ProDisc-C.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The goal for motion preservation at the implanted level was achieved using all 3 devices. The Synergy disc was unique in its ability to alter device angulation by 6°. The Bryan disc demonstrated device endplate kyphosis. Both the Synergy disc and ProDisc-C increased disc space height.</jats:p></jats:sec>

Three-dimensional motion analysis of the cervical spine for comparison of anterior cervical decompression and fusion versus artificial disc replacement in 17 patients

“…43 Three devices were included in that study: Bryan Cervical Disc, ProDisc-C (DePuy Synthes, Inc.), and Synergy Cervical Disc (Synergy Disc Replacement, Inc.). The study was concerned primarily with characteristics at the index level, analyzing postoperative range of motion, disc height, sagittal plane translation, angulation, and center of rotation.…”

“…34,36,58 One potential reason for the discrepancy in findings between previous studies may be due to the techniques used. Previous studies investigating cervical spine motion are often limited to a 2D analysis 18,34,39,43,45,53 or cadaveric simulations. 14,59 Although cadaveric simulations are ideal for measuring 3D motion patterns, they are not designed to reproduce the joint forces, muscle forces, and complex motion patterns associated with in vivo conditions.…”

Artroplastia total de disco cervical com prótese de Bryan: resultados clínicos e funcionais

“…Tem-se observado resultados semelhantes com essas próteses em curto prazo (dois anos de seguimento) 24,26 .…”

“…Na prática a artroplastia foi tão eficaz quanto a artrodese 26 . Na nossa casuística tivemos um único caso de mielopatia e a recuperação foi satisfatória com a artroplastia.…”

Can Cervical Arthroplasty Impact Alignment? A Comparison of the Synergy Disc with Cervical Fusion

“…In a retrospective cohort of 259 patients, neck pain was more common in the arthroplasty group at 15.8% (n=27 patients) when compared to the fusion group at 12.5% (n=11 patients) [21]. Although some authors have suggested that ball and socket can provide a modest increase in alignment, Rabin et al demonstrated that a lordotic configuration of ProDisc-C endplates was associated with restricted motion from neutral to extension [5,[22][23][24]. Similarly, Du et al described that even with a ball and socket design that incorporated 7˚ of lordosis in endplates (Discover Cervical Disc, DePuy Spine, Raynham MA, USA), there were reported cases of device endplate kyphosis [25].…”