Dynamic Cervical Implant in Treatment of Cervical Disc Disease

Anterior cervical decompression and fusion (ACDF) is the traditional method for treating degenerative cervical disc disease, providing satisfactory results in a high proportion of patients. However, stabilization of the treated segment may result in loss of mobility as a functional spinal unit and acceleration of degeneration of the adjacent disc. Re operations may be required to treat complications of fusion, such as recurrent radicular symptoms, non-union, graft collapse, or expulsion. Many previous studies have shown that loss of motion at the fused level is compensated by increased motion at adjacent segments after ACDF, which induces a high rate of degenerative change adjacent to the fused segment. Cervical non-fusion techniques have increasingly been accepted and applied by spine surgeons. As a main component of cervical non-fusion techniques, artificial cervical disc replacement provides good ROM of the cervical spine. Dynamic cervical stabilization with the DCI is a novel treatment approach for cervical disc disease that was initially conceived as a method to combine the potential advantages of fusion and total disc replacement. The first DCI was designed by Matgé in 2002 for treating cervical spondylosis. Paradigm spine introduced the second generation DCIs in 2005. A U-shaped appearance and axial elasticity are two the most significant characteristics. A prospective study by Matgé et al. in 2009 showed that the clinical efficacy was satisfactory after DCI replacement in 102 cases of cervical spondylosis and during a 1-year follow-up; there was neither device migration nor subsidence. The basic concept of the inter-body implant is to maintain a distraction-compression mechanism and so avoid possible collapse of the disc height. This is achieved using the special titanium-alloy DCI, which is bio compatible, available in various sizes, and provided with different foot prints. The U-shaped body provides support and has tooth-like serrations that resist expulsion or retropulsion of the implant when placed into the inter-vertebral space. With the end-plate left intact, osteogenesis and bone fusion are inhibited and no further hetero-topic fusions are supposed to occur. The initial clinical and radio graphic results with the DCI appear promising as an alternative to TDR and ACDF in the treatment of cervical disc disease. It affords maximal neurological improvement, along with maintenance of excellent clinical outcomes. The potential bio-mechanical advantages of DCI include the ability to maintain device-level motion and minimize the development of adjacent-segment disease, while protecting the facet joints from excessive stresses noted with other motion-preserving devices during lateral bending, axial rotation, and extension. The surgical technique included the use of a conventional anterior cervical approach and discectomy. As reported, disc replacement with DCI is a new strategy, in between ACDF \& ADR. It is an intermediate solution in the spectrum of management strategies of cervical disc diseases. Immediate dynamic stability with good clinical response and no implant-related morbidity or complications are the main advantages of this implant.