Since the last decade, the “golden standard” for treating cervical disc herniation has become cervical discectomy through an anterior approach, followed by fusion.To achieve fusion, a titanium or PEEK cage filled with bone substitute was inserted in the intervertebral space after removal of the disc. Although the short term results of this procedure were very satisfactory, after a few years, premature wearing out of the discs adjacent to the fusion was observed.. Although the short term results of this procedure were very satisfactory, after a few years, premature wearing out of the discs adjacent to the fusion was observed.
Surgical research therefore tried to find a solution that would allow not only the removal of the painful disc and restoration of the disc height, but also restoration of the spinal balance and of disc mobility in order to prevent adjacent level disease. This reflexion lead to the development of cervical disc prosthesis.
The main interest of cervical disc replacement is the preservation of mobility and the protection of the neighbouring levels. The operation is performed under microscope, and involves the removal of the painful disc and disc herniation, allowing decompression of the nerve roots or spinal cord. The prosthetic implant is then placed in the intervertebral space.
The implants are made of two artificial titanium endplates with a plasmapore coating that will allow bone integration on the surface of the prosthesis. These titanium endplates are separated by a polyurethane (Brian prosthesis) or polyethylene (Prodisc prosthesis) interface, that allows mobility and acts as an artificial joint between the two vertebras.
Preoperative routine assessment includes conventional X rays, cervical CT scan and/or magnetic resonance, and, occasionally, discography and bone scintigraphy.
Currently, we consider implanting a cervical disc prosthesis in cases of soft disc herniation in younger patients, presenting a disc space compatible with the size of the implant, and in cases of disc disease adjacent to a previously fused level. The cervical disc prosthesis is not indicated in osteoporotic patients, or in patients presenting with cervical canal stenosis, vertebral instability (spondylolisthesis), tumour or fracture.
Although lots of questions remain unanswered regarding the best type of implant or its life expectancy, about the implantation technique and mostly about the long term evolution of the disc level adjacent to the prosthesis, we believe that cervical disc prosthesis, far from being “experimental” anymore, have become not only an alternative to fusion, but really an original, anatomical and physiological treatment of cervical disc disease.
