PURPOSE: Recent studies describe significant rates of heterotopic ossification (HO) after cervical total disc replacement (CTDR). Little is known about the reasons, and one aspect that requires further in vivo investigation is the biomechanical alteration after CTDR and the role of the implant-related centre of rotation (CORi) in particular. The role of the sagittal position of the CORi on functional outcome in two versions of a semi-constrained disc prosthesis with sagittally different CORi is the topic of this study. METHODS: Patients were candidates for single-level CTDR between C3 and C7 who suffered from CDDD and received a standard or flat version of activ C™ (Aesculap AG, Tuttlingen). Clinical and radiographic assessments were determined preoperatively, intraoperatively, at discharge and again at 6 weeks, 6 months, 1 and 2 years. Radiographic examinations were performed independently using specialized quantitative motion analysis software. RESULTS: Clinical outcome improved significantly regarding NDI as well as VAS on neck and arm pain with no differences in mean improvement by study group. Segmental angle measures show a significantly better lordotic alignment for both groups after surgery, but the degree of correction achieved is higher in the flat group. Correlation analysis proves that the more anterior the CORi is positioned, the higher the lordotic correction is achieved (Pearson rho -0.385). Segmental ROM decreased in the standard group but was maintained for flat implants. At present, our data do not demonstrate a correlation between CORi and ROM at 2 years. Two years after surgery, severe HO grade III-IV was present in 31.6 % standard and 13.1 % flat cases with significant differences. Grouping according to HO severity showed comparable sagittal positions of CORi for flat implants but a more posterior position in the severe HO group for standard implants. CONCLUSIONS: Our results confirm the influence of CORi location on segmental alignment, kinematics and HO for a semi-constrained CTDR, but it also indicates a multifactorial process.

• MeSH
• artroplastika meziobratlové ploténky MeSH
• dospělí MeSH
• heterotopická osifikace etiologie   MeSH
• krční obratle diagnostické zobrazování   chirurgie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• lordóza diagnostické zobrazování   MeSH
• meziobratlová ploténka diagnostické zobrazování   chirurgie   MeSH
• následné studie MeSH
• prospektivní studie MeSH
• rentgendiagnostika MeSH
• stupeň závažnosti nemoci MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

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 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.

• MeSH
• ankylóza etiologie   patologie   patofyziologie   MeSH
• bolest krku etiologie   patologie   patofyziologie   MeSH
• čas MeSH
• časové faktory MeSH
• diskektomie škodlivé účinky   MeSH
• dospělí MeSH
• fúze páteře škodlivé účinky   MeSH
• heterotopická osifikace etiologie   patologie   patofyziologie   MeSH
• hlava - pohyby fyziologie   MeSH
• interní fixátory škodlivé účinky   MeSH
• krční obratle patologie   chirurgie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mechanický stres MeSH
• měření bolesti MeSH
• následné studie MeSH
• pooperační komplikace etiologie   patologie   patofyziologie   MeSH
• posuzování pracovní neschopnosti MeSH
• recidiva MeSH
• rozsah kloubních pohybů fyziologie   MeSH
• výhřez meziobratlové ploténky komplikace   patologie   chirurgie   MeSH
• zatížení muskuloskeletálního systému fyziologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH