[Cervical disc prostheses]

Endoprosthetic replacement for spinal cord disorders represents an attractive alternative to fusion in those cases where surgery appears necessary for degenerative disc disease. At least in theory it has been proven that placement of an endoprosthesis minimizes undue stress on the adjoining segments and its possible negative consequences. Furthermore, cervical endoprostheses facilitate speedier rehabilitation and the problems involved in removal of the bone chip become irrelevant. Clinical results reported to date for the cervical spine are very encouraging and indicate that endoprosthetic replacement has been quite successful particularly for difficulties in multilevel approaches. However, long-term results for cervical endoprostheses have not yet been published and therefore at present there are no reference values for the viability of the prosthesis with regard to the aseptic loosening rate. There are also no findings available on how the implanted cervical prosthesis will behave when bone quality diminishes at an advanced age.