Disk Replacement

About Disk Replacement

Artificial disc replacement, also called total disc arthroplasty, replaces a damaged intervertebral disc with a mechanical device designed to preserve motion at the treated level, as an alternative to spinal fusion. Cervical disc replacement is used for disc herniation or degenerative disease causing nerve root or spinal cord compression, usually at one or two levels, and several devices have been approved by regulators such as the US Food and Drug Administration. Lumbar disc replacement for low back pain is performed less commonly and remains more controversial. Devices typically consist of metal endplates anchored to the vertebrae with a bearing surface of metal or polyethylene between them, or a single piece designed to deform under load. The operation is performed from the front: in the neck through an incision similar to that used for anterior cervical discectomy and fusion, and in the lower back through an approach behind the abdominal contents, often with the help of a vascular surgeon. Proposed advantages over fusion include preserved motion, avoidance of bone graft and possibly less stress on adjacent levels. Randomized trials conducted for regulatory approval found cervical disc replacement at least comparable to fusion in selected patients over several years of follow up. Complications include subsidence or migration of the device, heterotopic ossification, bone formation that can reduce or eliminate motion, wear and adjacent segment disease. Contraindications generally include significant facet joint arthritis, osteoporosis, instability, infection and multilevel degeneration.