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SICOT e-Newsletter

Issue No. 44 - May 2012

Scientific Debate

Disc Replacement for Cervical Radiculopathy: Is it the new gold standard?

The traditional gold standard surgery for cervical radiculopathy has been Anterior Cervical Discectomy and Fusion (ACDF). Cervical Disc Arthroplasty has emerged as an alternative surgical procedure for the treatment of cervical radiculopathy. The decision to fuse or replace the cervical motion segment after neural decompression remains controversial. As a continuing initiative of the young surgeon's group of SICOT, we attempt to debate this controversial topic. The following debate is a personal opinion of each author based on his experiences and interpretation of literature; and in no way should be considered as an absolute guideline for management.

FOR CERVICAL ARTHROPLASTY

VG: Adjacent segment degeneration (ASD) is a significant problem with ACDF which is estimated to contribute to about a 3% re-operation rate per year [1]. Disc replacement following neural decompression for cervical radiculopathy has the advantage of retaining cervical motion. Preservation of segmental cervical motion reduces the stresses on the adjacent segment and hence reduces the incidence of ASD as well as delays its onset. Besides these advantages, artificial cervical disc replacement practically eliminates the risk of pseudoarthrosis that is associated with ACDF.

Preservation of segmental cervical motion has been demonstrated to be maintained for many years after disc replacement. Multicentre prospective randomised controlled trials have demonstrated that the outcomes of disc replacement are statistically superior to ACDF at 2 years follow-up [2-4]. Even at 4-5 years, the good outcome with disc replacement was maintained [5,6]. It has been shown that patients who get disc replacement are able to return to work earlier than patients who underwent an anterior cervical fusion.

Cervical disc replacement has been shown to be associated with a significantly lower re-operation rate at the adjacent segment as well as the same segment as compared to ACDF [2-5]. This is a manifestation of the favourable effect of motion preservation on the adjacent segment kinematics. Obviously, the complications of pseudoarthrosis and graft/spacer related complications occurring at the same level are not seen in patients who undergo disc replacement.

To conclude, cervical disc replacement is a successful operation which has shown to give excellent clinical results. It preserves cervical motion and reduces the risks of adjacent segment degeneration as well as pseudoarthrosis. To my mind, there is no doubt that disc replacement in an appropriately selected patient yields better results than fusion.

AGAINST CERVICAL ARTHROPLASTY

SR: The success of surgery for cervical radiculopathy depends upon neurological decompression rather than the technique of intervertebral reconstruction. Anterior cervical discectomy and fusion (ACDF) has been the gold standard operation for cervical radiculopathy for more than 30 years with more than 95% success rate [7]. I fail to see why one would replace a highly successful surgery with a new technique whose long-term safety profile is still unproven.

Disc replacement, even in the industry sponsored multicentre prospective randomised controlled trials, has shown only marginally superior outcomes as compared to ACDF [2-4]. I agree that the return to work has been shown to be quicker with disc replacement but then the same trials reported that the rate of employment at 2 years was similar between the two groups.

Disc replacement has many contraindications and nearly 60% of the patients with cervical radiculopathy are not suitable for a disc replacement [8]. One of the contraindications for disc replacement is facet arthropathy. In my experience, it is difficult to find a patient with disc degeneration but pristine facet joints. Proponents argue that disc replacement reduces the incidence of adjacent segment degeneration (ASD). This is yet to be proven conclusively by level I evidence [9]. Besides, ASD has been known to occur even with disc arthroplasty.

Disc replacement by itself is also associated with a new set of complications namely periprosthetic ankylosis, loss of motion, subsidence, focal kyphosis, implant loosening, need for revision surgery as well as sagittal split of the vertebral bodies [10]. In addition, there is a concern about the long-term safety profile with respect to serum metal ions and the wear debris in the vicinity of the spinal cord and the retro pharynx.

To conclude, I see no justification in changing our practice unless the superiority and long-term safety of disc arthroplasty is conclusively proven. Add to this argument the additional cost of disc replacement and the dice is heavily loaded in favour of ACDF.

  
References:

  1. Hilibrand AS, Carlson GD, Palumbo MA, Jones PK, Bohlman HH. Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am. 1999;81(4):519-28.
  2. Heller JG, Sasso RC, Papadopoulos SM, Anderson PA, Fessler RG, Hacker RJ, Coric D, Cauthen JC, Riew DK. Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial. Spine 2009;34(2):101-7.
  3. Mummaneni PV, Burkus JK, Haid RW, Traynelis VC, Zdeblick TA. Clinical and radiographic analysis of cervical disc arthroplasty compared with allograft fusion: a randomized controlled clinical trial. J Neurosurg Spine 6:198–209, 2007.
  4. Murrey D, Janssen M, Delamarter R, Goldstein J, Zigler J, Tay B, Darden B. Results of the prospective, randomized, controlled multicenter Food and Drug Administration investigational device exemption study of the ProDisc-C total disc replacement versus anterior discectomy and fusion for the treatment of 1-level symptomatic cervical disc disease. Spine J 9:275–286, 2009.
  5. Ben J. Garrido, Tarek A. Taha, Rick C. Sasso. Clinical Outcomes of Bryan Cervical Disc Arthroplasty. A Prospective, Randomized, Controlled, Single Site Trial With 48-Month Follow-up. J Spinal Disord Tech 2010;23:367–371.
  6. J. Kenneth Burkus, Regis W. Haid Jr., Vincent C. Traynelis, Praveen V. Mumm aneni. Long-term clinical and radiographic outcomes of cervical disc replacement with the Prestige disc: results from a prospective randomized controlled clinical trial. J Neurosurg Spine 13:308–318, 2010.
  7. Fraser JF, Härtl R. Anterior approaches to fusion of the cervical spine: a metaanalysis of fusion rates. J Neurosurg Spine 6:298–303, 2007.
  8. Auerbach JD, Jones KJ, Fras CI, Balderston JR, Rushton SA, Chin KR. The prevalence of indications and contraindications to cervical total disc replacement. Spine J. 2008 Sep-Oct;8(5):711-6.
  9. Ingrid Zechmeister, Roman Winkler, Philipp Mad. Artificial total disc replacement versus fusion for the cervical spine: a systematic review. Eur Spine J. 2011 Feb;20(2):177-84.
  10. V. Denaro, R. Papalia, L. Denaro, A. Di Martino, N. Maffulli. ASPECTS OF CURRENT MANAGEMENT. Cervical spinal disc replacement. J Bone Joint Surg [Br] 2009;91-B:713-19.

Authors:

VG: Vijay Goni, MS (Ortho), is a Consultant Orthopaedic Surgeon at the Postgraduate Institute of Medical Education and Research, Chandigarh, India. He is specialised in spine surgery.

SR: Saurabh Rawall, MS (Ortho), FNB (Spine Surgery), is a Clinical Fellow in Spine Surgery at the University of Calgary, Alberta, Canada.