Disc arthroplasty - surgical update

Nicholas Little

Royal North Shore Hospital, Sydney, Australia

cSpinal disc arthroplasty is a rapidly expanding and controversial area of spinal surgery. Whether it is evolution, revolution or just another substantial source of income for prosthesis companies remains to be seen. I will discuss briefly the history of surgery to fuse the spine and the rationale behind arthroplasty. I will present the surgical and anaesthetic challenges presented by arthroplasty and the results that are available for this treatment to date.
The differences in constraint and mobility of prostheses will be considered along with the clinical consequences.
Orthopods have known for a long time that to fuse a painful joint will often make it less painful. This approach had a substantial mechanical cost to the patient and has lead to arthroplasty becoming the gold standard for treatment of large painful/degenerative peripheral joints (eg. Hips, knees). Whether this mechanical benefit of arthroplasty over fusion applies to the spine is the crux of the discussion. The mechanical consequences of spinal fusion at one level are significantly less than that of a large peripheral joint. The indications for spinal surgery, often for axial pain, are often far less clear than that for other joints and outcome measures are flawed. In the end is the argument against arthroplasty one of cost control (as has recently occurred with cervical arthroplasty in Australia) or are there other dangers of embracing this technology. There are specific risks with both cervical and lumbar arthroplasty and will seductive new technology lead to expansion of indications beyond what is reasonable.
As with most areas of medicine we need to critically evaluate new technology and procedures with an eye on individual patient benefit in the context of ever increasing financial burden on the system. Conflicts and barriers to good medical care such as relationships between prosthesis companies and surgeons need to be transparent or avoided where possible.
I believe spinal arthroplasty will grow in popularity and is an appropriate treatment strategy, which will change the way we think about spinal mechanics. How we handle this revolution is a challenge requiring care and restraint.