Radiological changes of the operated and adjacent segments following cervical arthroplasty after a minimum 24-month follow-up: comparison between the Bryan and Prodisc-C devices

Abstract

Object. The purposes of this retrospective study were to determine the radiological changes at the index and adjacent levels after cervical arthroplasty using the Bryan disc and Prodisc-C disc after a minimum 24 months followup, and to demonstrate the possible clinical factors related to these changes. Methods. Following single-level cervical arthroplasty using either the Bryan disc or Prodisc-C, the degree of facet degeneration and other radiological changes at the index and adjacent levels were assessed by observing radiographs and CT scans at a minimum 24 months after the operations. These findings were determined in relation to the clinical outcome, various perioperative factors, and prosthesis factors. Thirty-six patients were included in this investigation (19 in the Bryan disc group and 17 in the Prodisc-C group).Results. At the index level, progression of facet arthrosis (PFA) was observed in 7 of 36 levels (1 level with the Bryan disc, 6 with the Prodisc-C). At adjacent levels, PFA was minimally observed. Heterotopic ossification (HO) was observed at 19 levels (11 with the Bryan disc, 8 with Prodisc-C). Progression of facet arthrosis at the index segments was positively related to malposition of the prosthesis on the frontal plane, and decreased postoperative functional spinal unit range of motion at the index level. Occurrence of HO was correlated with the preoperative calcification of the posterior longitudinal ligament at the operated level, regardless of prosthesis type. Clinical outcome and the occurrence of PFA or HO did not show any significant relationship.Conclusions. This study demonstrates that the incidence of PFA at the index level is 19.4% after a minimum 24-month follow-up, and occurs more frequently in the Prodisc-C group. Progression of facet arthrosis is related to less functional spinal unit range of motion and anterior placement of the prosthesis. The occurrence rate of HO is high, regardless of the type of prosthesis, and it is significantly correlated with preoperative calcification of the posterior longitudinal ligament at the operated level. (DOI: 10.3171/2010.3.SPINE09445) Key WoRDS

Editorial

“…Although the data in the paper by Ryu et al 8 are interesting, this study has a number of important limitations. The strength of the conclusions is limited by the retrospective, consecutive patient design.…”

“…Ryu et al 8 should be commended for including a broad spectrum of radiographic outcome measures and trying to relate these to in vivo clinical outcomes. Should arthroplasty devices maintain pathological ROM or restore it?…”

Uncovertebral hypertrophy is a significant risk factor for the occurrence of heterotopic ossification after cervical disc replacement: survivorship analysis of Bryan disc for single-level cervical arthroplasty

“…There are several theories related to the cause of HO, but none provide a satisfactory explanation of its features [9,10,16]. One report suggested that age and sex are possible risk factors for the occurrence of HO [10], other authors have reported no relationship between sex and occurrence of HO [9,16].…”

“…Most of the recent studies on HO have demonstrated an unacceptably higher occurrence rate than expected after cervical arthroplasty [1,9,16,22]. Yi et al [24] even insisted that HO after cervical disc replacement surgery is an inevitable postoperative complication, although differences in occurrence rates were observed according to the prosthesis type.…”

Anterior Cervical Discectomy - An Overview of Technique and Developments for the Future

“…[27][28][29][30] A specific complication related to cervical disc prostheses is periprosthetic ossification. [31][32][33][34][35][36] Bone is formed around the prosthesis and can restrict movement. It is remarkable that this occurrence does not alter clinical outcome.…”