The indications for lumbar and cervical disc replacement.

Although cervical and lumbar disc replacements are in their spinal surgical infancy with regard to clinical application, the indications are already delineated. Lumbar disc arthroplasty is indicated for one- or two-level discogenic mechanical back pain primarily in the absence of radiculopathy. In contrast, cervical disc replacement can be readily applied in patients presenting with neurologic deficit, radiculopathy or myelopathy because the approach and anterior spinal cord decompression are identical for anterior cervical disc replacement and traditional Smith-Robinson cervical decompression. In addition, the application of more complex spinal osteotomies, revision of pseudarthroses and deformity correction are much more applicable to the cervical arthroplasty procedures. This is because even the most experienced vascular access surgeon has difficulty with the formidable revision through a repeat anterior lumbar procedure, whereas most experienced cervical spinal surgeons are familiar with repeat anterior cervical approaches. The end result is that surgeons will have more trepidation with multilevel lumbar arthroplasties, especially those presenting in conjunction with neurologic symptoms. At the current time radiculopathy is an exclusion criteria for the four prospective Investigational Device Exemption (IDE) Food and Drug Administration (FDA) studies on lumbar disc replacement, whereas cervical radiculopathy is an inclusion criteria for the major IDE FDA investigations of cervical arthroplasties.