Spinal motion restoration devices for the degenerative disc

Cervical and lumbar degenerative disc disease is common in today's society and can be associated with significant pain and disability (Taksali et al. 2004). Spinal fusion continues to be the most common surgical treatment for degenerative conditions in the neck and low back (Davis 1994; Lee and Langrana 2004). While fusion has been similarly used for the treatment of degenerative arthritis of the hip and knee joints, it has been replaced by revolutionary joint arthroplasty techniques with excellent outcomes in terms of relieving pain and restoring function (Santos et al. 2004). In contrast, disc arthroplasty has only recently been considered an alternative to spinal arthrodesis and has not replaced fusion as the gold standard treatment. Studies regarding spinal fusion for degenerative disc disease have demonstrated inconsistent clinical results even in properly selected patients, and despite advances in spinal fusion technique and instrumentation, patient outcomes have not been significantly altered (Barrick et al. 2000; Kleeman et al. 2001; Madan and Boeree 2003; Bono and Lee 2004; Lee and Langrana 2004; Santos et al. 2004).