Mobile total disc replacement prosthesis Mobi-C, our experience. Results of the study with five years follow-up
Abstract
Aim: To present the clinical outcome and radiological findings in a group of patients five years after the implantation of mobile total disc replacement prostheses Mobi-C Material and Methods: Retrospection of prospectively collected data after 5 years from 17 patients with 18 disc prostheses Mobi-C implanted at the Department of Neurosurgery, Charles University Teaching Hospital in Plzen, Czech Republic. Inclusive data were symptoms of radiculopathy and/or myelopathy in correlation with a soft disc herniation on magnetic resonance.
Development of Visual Analogue Scale (VAS), modified Japanese Orthopaedic Association Scale (mJOA) and Nurick Scale were followed. The range of motion of the operated spinal segment and the whole cervical spine was studied from dynamic X rays.
Heterotopic ossification was evaluated according to Mehren classification. The results were statistically tested with the nonparametric Wilcoxon test on a level of 0.05 significance.
Results: Range of motion five years after the implantation was not restricted, the median stayed on the same value of 7.0 (p=0,2932), the range of motion of the whole cervical spine was not significant either; median 36 to 48 (p=0.0997). Heterotopic ossification of degree 0 was found in 28 %, bony fusion, degree IV, in 11 %.
Statistically significant improvement in neurological findings was found in all patients. The VAS median changed from 5.5 to 2 (p=0.0009) and mJOA median from 16 to 18 (p=0.0025).
Conclusions: Total disc replacement with mobile prosthesis Mobi-C is an effective option in the treatment of cervical disc degeneration according to the clinical outcome. The range of motion of the operated segment was not reduced during the five years after the implantation.
The correlation between the clinical outcome and the range of motion of the prosthesis was not found.