Cervical Artificial Disc Replacement

Abstract

This article is the first of 2 parts. Cervical artificial disc replacement represents an exciting new frontier in spine surgery for degenerative cervical disease. This article reviews the history, development, and biomechanics of the cervical artificial disc. An analytical comparison of the currently available arthroplasty systems is also presented. Cervical disc arthroplasty focuses on preserving motion at the treated level while minimally affecting motion in the adjacent levels. The postulated advantage of this approach is a reduction in adjacent level degenerative disease. However, more comprehensive biomechanical data are needed before arthroplasty devices are widely accepted and implanted. Computational analysis of cervical spine load transmission will enhance the available knowledge and facilitate the design of the next generation of prostheses.

Long-Term Functional and Symptomatic Outcomes of Cervical Disc Prostheses

“…Robinson and Smith and later Cloward were the first to develop the technique of anterior cervical discectomy and fusion for cervical disc disease and spondylosis (15,19) . The clinical results were favorable, but the disadvantages of the procedure were the elimination of motion in a formerly mobile functional segment and hypermobility at adjacent segments, which caused increased strain in the adjacent segments resulting in further disc degeneration and instability (13,15) . Segments adjacent to fusion may have increased range of motion (ROM) and increased intradiscal pressure, causing recurrence of neurological symptoms and degenerative changes adjacent to the fused cervical levels (20) .…”

“…Although Reizt and Joubert reported satisfactory results (10) , these devices have a high risk of steel ball subsidence to the vertebral corpuses eventually leading to fusion. Different alternative cervical discs have been invent-ed since than such as Bryan, ProDisc-C, PCM, Prestige, Cervi Core, Mobi-C (15) . These different designs consist of either articulating or non-articulating components constructed from various materials.…”

“…Cervical disc arthroplasty aims motion preservation at the operated level while minimizing adjacent level degenerative disease through restoration of cervical motion at operated level by preserving the normal kinematics of the spine and by prevention of normal motion at the adjacent levels. The technique reconstitutes the space height, thus maintains the neural decompression and aims to maintain the stability at the operated level (15,20) . In addition, these devices do not complicate a subsequent fusion procedure if the arthroplasty fails and leads to a painful pseudarthrosis.…”

“…It has been documented that the conventional cervical surgical technique, namely ACDF surgery, causes improvements in NDI and VAS (29) . Some studies examined outcomes of fusion patients (30)(31)(32)(33)(34) , whereas others compared fusion with arthroplasty (15,16,26,28,(35)(36)(37) . Neck pain, arm pain and NDI generally show significant improvements during the follow-up of patients after ACDF (38) .…”

“…Anterior decompression of the disc with or without interbody cage has been performed for the cervical pathologies causing myelopathy and radiculopathy with the aim of obtaining fusion after discectomy at the operated level (7)(8)(9)(10)(11)(12) . Although this surgical technique generally results in success, many disadvantages have been reported (13,14) , prompting surgeons to discover alternative methods, such as cervical disc arthroplasty, which aims preservation of motion at the operated level while minimizing degenerative disease at adjacent levels (15,16) .…”