Letter to the Editor: Cervical disc arthroplasty: nonconstrained versus semiconstrained

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TO THE EDITOR: We read with great interest the article by Dr. Heary and colleagues8 in the December issue of the Journal of Neurosurgery: Spine (Heary RF, Goldstein IM, Getto KM, et al: Solid radiographic fusion with a nonconstrained device 5 years after cervical arthroplasty. J Neurosurg Spine 21:951–955, December 2014). The authors reported the case of a patient who underwent cervical disc arthroplasty (CDA) using the DISCOVER artificial disc (DePuy Synthes Spine Inc.). Five years after the surgery, spontaneous fusion at the surgical level was identified, despite excellent clinical outcomes. The authors’ article provided valuable information regarding an unexpected radiographic finding that occurred but did not affect the clinical outcome. However, there is a fundamental issue that needs to be clarified before claiming that this is the first identification of fusion around a nonconstrained cervical artificial disc.

In many reports the Bryan disc (Medtronic Sofamor Danek Inc.) has been considered as nonconstrained.1,3,6,7,10,12–15 Unlike the ball-and-socket articulating design of ProDisc-C (DePuy Synthes Spine Inc.) or the Prestige disc (Medtronic Sofamor Danek Inc.), the Bryan disc is composed of 2 pieces of titanium alloy shells and a polyurethane nucleus in between, surrounded by a polyurethane sheath with lubricant inside. This bi-articulating metal-on-polymer design naturally allows for translational and unconstrained motion through a physiological range of motion, including flexion-extension, lateral bending, and axial rotation. The fully variable instantaneous center of rotation (COR) of the Bryan disc has led to some concerns over extra loading of the facets and potential kyphosis.6,9,17 On the other hand, ProDisc-C and Prestige discs were often considered semiconstrained4,10 because of their predetermined COR of the ball-and-socket design and relatively lower allowance for translation.5

Spontaneous fusion or development of heterotopic ossification (HO) after CDA with a Bryan disc has been reported many times.2,11,16,18,19 It is reasonable to anticipate more incidences of this undesired bone formation after CDA, as the application of this technology increases and the follow-up is extended. Whether or not the HO is related to the biomechanical design remains elusive. Furthermore, the differences between the more- and lessconstrained devices for CDA may be less substantial than those for large joint arthroplasty.

The treatment of cervical degenerative disc disease and spondylosis with CDA is a science with ongoing development. The authors are commended for sharing their precious clinical experience with the worldwide readers of the Journal of Neurosurgery: Spine. However, it would be more helpful if they provided a detailed explanation of the nomenclature of CDA devices and a comparison of the types of constraint had by Bryan and DISCOVER discs.

References

  • 1

    Anderson PASasso RCRouleau JPCarlson CSGoffln J: The Bryan Cervical Disc: wear properties and early clinical results. Spine J 4:6 suppl303S309S2004

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    • Export Citation
  • 2

    Bartels RHDonk R: Fusion around cervical disc prosthesis: case report. Neurosurgery 57:E1942005

  • 3

    Bertagnoli RDuggal NPickett GEWigfleld CCGill SSKarg A: Cervical total disc replacement, part two: clinical results. orthop clin North am 36:3553622005

    • Search Google Scholar
    • Export Citation
  • 4

    Chang UKKim DHLee MCWillenberg RKim SHLim J: Changes in adjacent-level disc pressure and facet joint force after cervical arthroplasty compared with cervical discectomy and fusion. J Neurosurg spine 7:33392007

    • Search Google Scholar
    • Export Citation
  • 5

    Darden BVCervical disc arthroplasty. Fokter S: Recent advances in arthroplasty Rijeka, CroatiaInTech2012. 499514

  • 6

    Fong SYDuPlessis SJCasha SHurlbert RJ: Design limitations of Bryan disc arthroplasty. Spine J 6:2332412006

  • 7

    Goffln JCasey AKehr PLiebig KLind BLogroscino C: Preliminary clinical experience with the Bryan Cervical Disc Prosthesis. Neurosurgery 51:8408472002

    • Search Google Scholar
    • Export Citation
  • 8

    Heary RFGoldstein IMGetto KMAgarwal N: Solid radiographic fusion with a nonconstrained device 5 years after cervical arthroplasty. J Neurosurg spine 21:9519552014

    • Search Google Scholar
    • Export Citation
  • 9

    Kang HPark PLa Marca FHollister SJLin CY: Analysis of load sharing on uncovertebral and facet joints at the C5–6 level with implantation of the Bryan, Prestige LP, or ProDisc-C cervical disc prosthesis: an in vivo image-based finite element study. Neurosurg Focus 28:6E92010

    • Search Google Scholar
    • Export Citation
  • 10

    Park SBKim KJJin YJKim HJJahng TAChung CK: X-ray based kinematic analysis of cervical spine according to prosthesis designs: analysis of the Mobi C, Bryan, PCM, and Prestige LP. J spinal Disord Tech epub ahead of print2013

    • Search Google Scholar
    • Export Citation
  • 11

    Parkinson JFSekhon LH: Cervical arthroplasty complicated by delayed spontaneous fusion. Case report. J Neurosurg Spine 2:3773802005

    • Search Google Scholar
    • Export Citation
  • 12

    Sasso RCBest NM: Cervical kinematics after fusion and Bryan disc arthroplasty. J spinal Disord Tech 21:19222008

  • 13

    Sasso RCSmucker JDHacker RJHeller JG: Clinical outcomes of BRYAN cervical disc arthroplasty: a prospective, randomized, controlled, multicenter trial with 24-month follow-up. J Spinal Disord Tech 20:4814912007

    • Search Google Scholar
    • Export Citation
  • 14

    Sekhon LHBall JR: Artificial cervical disc replacement: principles, types and techniques. Neurol india 53:4454502005

  • 15

    Shi RLi JLiu HDing CHu TLi T: Clinical comparison of 2 implantation systems for single-level cervical disk replacement. Orthopedics 37:e161e1682014

    • Search Google Scholar
    • Export Citation
  • 16

    Tu THWu JCHuang WCGuo WYWu CLShih YH: Heterotopic ossification after cervical total disc replacement: determination by CT and effects on clinical outcomes. J Neurosurg spine 14:4574652011

    • Search Google Scholar
    • Export Citation
  • 17

    Walraevens JRLiu BSloten JVDemaerel PGoffin J: Postoperative segmental malalignment after surgery with the Bryan cervical disc prosthesis: is it related to the mechanics and design of the prosthesis?. J spinal Disord Tech 23:3723762010

    • Search Google Scholar
    • Export Citation
  • 18

    Wu JCHuang WCTsai HWKo CCFay LYTu TH: Differences between 1- and 2-level cervical arthroplasty: more heterotopic ossification in 2-level disc replacement. Clinical article. J Neurosurg spine 16:5946002012

    • Search Google Scholar
    • Export Citation
  • 19

    Wu JCHuang WCTu THTsai HWKo CCWu CL: Differences between soft-disc herniation and spondylosis in cervical arthroplasty: CT-documented heterotopic ossification with minimum 2 years of follow-up. J Neurosurg spine 16:1631712012

    • Search Google Scholar
    • Export Citation
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Article Information

Contributor Notes

INCLUDE WHEN CITING Published online June 5, 2015; DOI: 10.3171/2015.1.SPINE141313.DISCLOSURE The authors report no conflict of interest.

© Copyright 1944-2019 American Association of Neurological Surgeons

Headings
References
  • 1

    Anderson PASasso RCRouleau JPCarlson CSGoffln J: The Bryan Cervical Disc: wear properties and early clinical results. Spine J 4:6 suppl303S309S2004

    • Search Google Scholar
    • Export Citation
  • 2

    Bartels RHDonk R: Fusion around cervical disc prosthesis: case report. Neurosurgery 57:E1942005

  • 3

    Bertagnoli RDuggal NPickett GEWigfleld CCGill SSKarg A: Cervical total disc replacement, part two: clinical results. orthop clin North am 36:3553622005

    • Search Google Scholar
    • Export Citation
  • 4

    Chang UKKim DHLee MCWillenberg RKim SHLim J: Changes in adjacent-level disc pressure and facet joint force after cervical arthroplasty compared with cervical discectomy and fusion. J Neurosurg spine 7:33392007

    • Search Google Scholar
    • Export Citation
  • 5

    Darden BVCervical disc arthroplasty. Fokter S: Recent advances in arthroplasty Rijeka, CroatiaInTech2012. 499514

  • 6

    Fong SYDuPlessis SJCasha SHurlbert RJ: Design limitations of Bryan disc arthroplasty. Spine J 6:2332412006

  • 7

    Goffln JCasey AKehr PLiebig KLind BLogroscino C: Preliminary clinical experience with the Bryan Cervical Disc Prosthesis. Neurosurgery 51:8408472002

    • Search Google Scholar
    • Export Citation
  • 8

    Heary RFGoldstein IMGetto KMAgarwal N: Solid radiographic fusion with a nonconstrained device 5 years after cervical arthroplasty. J Neurosurg spine 21:9519552014

    • Search Google Scholar
    • Export Citation
  • 9

    Kang HPark PLa Marca FHollister SJLin CY: Analysis of load sharing on uncovertebral and facet joints at the C5–6 level with implantation of the Bryan, Prestige LP, or ProDisc-C cervical disc prosthesis: an in vivo image-based finite element study. Neurosurg Focus 28:6E92010

    • Search Google Scholar
    • Export Citation
  • 10

    Park SBKim KJJin YJKim HJJahng TAChung CK: X-ray based kinematic analysis of cervical spine according to prosthesis designs: analysis of the Mobi C, Bryan, PCM, and Prestige LP. J spinal Disord Tech epub ahead of print2013

    • Search Google Scholar
    • Export Citation
  • 11

    Parkinson JFSekhon LH: Cervical arthroplasty complicated by delayed spontaneous fusion. Case report. J Neurosurg Spine 2:3773802005

    • Search Google Scholar
    • Export Citation
  • 12

    Sasso RCBest NM: Cervical kinematics after fusion and Bryan disc arthroplasty. J spinal Disord Tech 21:19222008

  • 13

    Sasso RCSmucker JDHacker RJHeller JG: Clinical outcomes of BRYAN cervical disc arthroplasty: a prospective, randomized, controlled, multicenter trial with 24-month follow-up. J Spinal Disord Tech 20:4814912007

    • Search Google Scholar
    • Export Citation
  • 14

    Sekhon LHBall JR: Artificial cervical disc replacement: principles, types and techniques. Neurol india 53:4454502005

  • 15

    Shi RLi JLiu HDing CHu TLi T: Clinical comparison of 2 implantation systems for single-level cervical disk replacement. Orthopedics 37:e161e1682014

    • Search Google Scholar
    • Export Citation
  • 16

    Tu THWu JCHuang WCGuo WYWu CLShih YH: Heterotopic ossification after cervical total disc replacement: determination by CT and effects on clinical outcomes. J Neurosurg spine 14:4574652011

    • Search Google Scholar
    • Export Citation
  • 17

    Walraevens JRLiu BSloten JVDemaerel PGoffin J: Postoperative segmental malalignment after surgery with the Bryan cervical disc prosthesis: is it related to the mechanics and design of the prosthesis?. J spinal Disord Tech 23:3723762010

    • Search Google Scholar
    • Export Citation
  • 18

    Wu JCHuang WCTsai HWKo CCFay LYTu TH: Differences between 1- and 2-level cervical arthroplasty: more heterotopic ossification in 2-level disc replacement. Clinical article. J Neurosurg spine 16:5946002012

    • Search Google Scholar
    • Export Citation
  • 19

    Wu JCHuang WCTu THTsai HWKo CCWu CL: Differences between soft-disc herniation and spondylosis in cervical arthroplasty: CT-documented heterotopic ossification with minimum 2 years of follow-up. J Neurosurg spine 16:1631712012

    • Search Google Scholar
    • Export Citation
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