Clinical results and development of heterotopic ossification in total cervical disc replacement during a 4-year follow-up

Abstract

Cervical total disc replacement (CTDR) aims to decrease the incidence of adjacent segment disease through motion preservation in the operated disc space. Ongoing data collection and increasing number of studies describing heterotopic ossification (HO) resulting in decreased mobility of implants, forced us to carefully evaluate our long-term clinical and morphological results of patients with CTDR. We present the first 54 consecutive patients treated with 65 ProdiscC TM prostheses during a 12-month period (2/2004-3/2005). All patients signed an informed consent and were included in prospective long-term study approved by hospital ethical committee. The 1-and 2-year follow-up analysis were available for all patients included and 4-year results for 50 patients (60 implants). Clinical (neck disability index-NDI, visual analog scale-VAS) and radiological follow-up was conducted at 1-, 2-and 4-years after the procedure. The Mehren/Suchomel modification of McAfee scale was used to classify the appearance of HO. Mean preoperative NDI was 34.5%, VAS for neck pain intensity 4.6 and VAS for arm pain intensity 5.0. At 1-, 2-and 4-year follow-up, the mean NDI was 30.7, 27.2, and 30.4, mean VAS for neck pain intensity 2.5, 2.1 and 2.9 and mean VAS for arm pain intensity pain 2.2, 1.9 and 2.3, respectively. Significant HO (grade III) was present in 45% of implants and segmental ankylosis (grade IV) in another 18% 4 years after intervention. This finding had no clinical consequences and 92% of patients would undergo the same surgery again. Our clinical results (NDI, VAS) are comparable with fusion techniques. Although, advanced non-fusion technology is used, a significant frequency of HO formation and spontaneous fusion in cervical disc replacement surgery must be anticipated during long-term follow-up.

Clinical and radiological outcome at 10 years of follow-up after total cervical disc replacement

“…Similar observations were verified in a number of studies, which demonstrated comparable post-operative scores at different long-term observation periods, ranging between 4 and 30 years, and irrespective of the type of prosthesis used [2][3][4][16][17][18][19].…”

“…Qureshi et al analysed the cost-effectiveness comparing single level TDR and ACDF and conclude also that cTDR and ACDF are cost-effective procedures, but cTDR must remain functional for at least 14 years to establish greater cost-effectiveness than ACDF [34]. The appearance of HO right up to solid fusion (Grade 4) is a well known complication in cervical total disc replacement which can affect the motion, respectively, the function of the prosthesis [31,32,35] regardless the implant-type [7,11,17,27,28,[36][37][38][39]. The progression of HO into higher grades over time was also seen in other studies [28,32].…”

Heterotopic ossification and clinical outcome in nonconstrained cervical arthroplasty 2 years after surgery: the Norwegian Cervical Arthroplasty Trial (NORCAT)

“…On the other hand, Qizhi et al [29], who used the Discover device in two-level disc surgery, found no HO after 32,4 months. Tu et al [18] reported 50 % HO with the Bryan device at a mean 19 months follow-up, and Suchomel et al [28] found high-grade HO in 63 % after 4 years with the ProDisc-C. Thus, different degrees of constraints seem to influence the development of HO, but HO also differs among devices with the same degree of constraint and in different reports concerning the same device.…”

Footprint mismatch in total cervical disc arthroplasty

“…Mehren et al reported an ossification rate of 49.4 % one year after implantation of disc device and suspected an even higher rate of spontaneous fusion after long-term follow-up [13]. The reported incidence of spontaneous fusion after ACDA varies from 18 % after 4 years [14] to 60 % after 5 years following implantation [15]. To minimise failures in ACDA, good implant design is required.…”