To critically review the state of the emerging field of cervical disc replacement.
Although anterior cervical decompression and fusion (ACDF) has been used successfully in the treatment of symptomatic radiculopathy and/or myelopathy, biomechanical studies have reported the deleterious effects of cervical fusion on adjacent level kinematics. Proponents of cervical disc replacement claim that maintenance of motion at the operated level will reduce the incidence of adjacent level degeneration and improve long-term clinical outcomes when compared with ACDF.
A systematic review of the literature dealing with cervical disc replacement and technologies of arthroplasty design that may have relevance to the cervical spine. A review of the design characteristics and published clinical data for cervical prostheses undergoing Investigational Device Exemption (IDE) study in the United States is provided.
Current cervical disc replacement designs include one-piece implants and implants with single- or double-gliding articulations with either metal-on-metal or metal-on-polymer bearing surfaces. Reports of in vitro wear testing have claimed substantially less wear for cervical implants than that seen with prosthetic hips and knees. Short-term clinical results after decompression and cervical disc replacement for the treatment of cervical radiculopathy and/or myelopathy are encouraging. Prospective, randomized trials are lacking.
Cervical disc replacement is an innovative technology that preserves motion at the instrumented level/s and will potentially improve load transfer to the adjacent levels compared with fusion. Clinical reports of success of cervical total disc replacement are encouraging but are also quite preliminary. As the U.S. IDE studies are completed, a clearer role for the place of cervical disc replacement in the spine surgeon’s armamentarium should emerge.
Cervical disc replacement preserves motion at the treated level(s) and improves load transfer to the adjacent levels when compared with fusion. Implant design characteristics are critical for functioning and longevity of cervical disc replacements, and the consequences of failure of the implant in close proximity to the spinal cord, esophagus, and trachea must be considered. Clinical reports of success of cervical TDR are encouraging but are also quite preliminary.
From the Rush University Medical Center, Chicago, IL.
Acknowledgment date: February 23, 2005. Acceptance date: May 31, 2005.
The device(s)/drug(s) that is/are the subject of this manuscript is/are not FDA-approved for this indication and is/are not commercially available in the United States.
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Frank M. Phillips, MD, Rush University Medical Center 1725 W. Harrison Street, Suite 1063, Chicago, IL 60062; E-mail: firstname.lastname@example.org