Influence of an artificial cervical joint compared with fusion on adjacent-level motion in the treatment of degenerative cervical disc disease

Abstract

<jats:p content-type="fine-print"><jats:italic>Object.</jats:italic> The authors report the preservation of motion at surgically treated and adjacent spinal segments after placing an artificial cervical joint (ACJ) and they describe the influence of interbody fusion on changes in angulation occurring in the sagittal plane at adjacent levels in the treatment of cervical spondylosis.</jats:p> <jats:p content-type="fine-print"><jats:italic>Methods.</jats:italic> The authors conducted a prospective nonrandomized study of patients in whom an ACJ was placed or autologous bone graft interbody fusion was performed. Angular measurements at levels adjacent to that surgically treated were calculated using plain flexion—extension radiographs obtained at 6-month intervals. Analyses of qualitative data, such as increase or decrease in adjacent-level motion, and the degree of disc degeneration were performed. Quantitative data were also analyzed. In the fusion group a significant increase in adjacent-level movement was demonstrated at the 12-month follow-up visit compared with the group of patients in whom ACJs were placed (p &lt; 0.001). The increase in movement occurred predominantly at intervertebral discs that were preoperatively regarded as normal (p &lt; 0.02). An overall reduction in adjacent-level movement was observed in patients who underwent joint replacement, although this was compensated for by the movement provided by the ACJ itself.</jats:p> <jats:p content-type="fine-print"><jats:italic>Conclusions.</jats:italic> Fusion results in increased motion at adjacent levels. The increase in adjacent-level motion derives from those discs that appear radiologically normal prior to surgery. It remains unknown whether ACJs have a protective influence on adjacent intervertebral discs.</jats:p>

Assessment of adjacent-segment mobility after cervical disc replacement versus fusion: RCT with 1 year’s results

“…The fusion group demonstrated a higher segmental motion at the adjacent level in comparison to prostheses [45]. However, the increased ROM in patients with ACDF was distributed at spinal levels with no X-ray evidence of degenerative disc disease and not at discs with radiographic degenerative changes [45].…”

“…Wigfield et al [45,46] prospectively compared the ROM between nonrandomized patients with ACDF and patients with prostheses. The fusion group demonstrated a higher segmental motion at the adjacent level in comparison to prostheses [45].…”

“…There are many potentially important factors associated with the development of adjacent segment disease, starting with increased segmental motion, stress, load, and intradiscal pressure at levels adjacent to the fusion site [4,6,26,33,34,43,45,46].…”

Cervical disc prosthesis versus arthrodesis using one-level, hybrid and two-level constructs: an in vitro investigation

“…Because TDR is an emerging technology with the need for evaluation, most laboratory and clinical studies first investigated safety and efficacy of cervical TDR at one-level [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. However, multi-segmental cervical spondylosis is not rare in clinical practice.…”

Three-dimensional kinematic analysis of the cervical spine after anterior cervical decompression and fusion at an adjacent level: a preliminary report

“…In vivo kinematic studies using flexion/extension plain radiograms have also addressed the effects of anterior cervical fusion on the kinematics at the adjacent levels to fusion [4,8,[15][16][17][18][19][20][21][22]. Results of these studies were also variable.…”