By Scott Blumenthal.
Being an international society focusing on motion preserving technologies, the 2010 SAS (formerly the Spine Arthroplasty Society which is now in the process of undergoing re-naming) provided the perfect forum for an update on the use of total disc replacement (TDR) from around the world.
A faculty was assembled to represent six continents: Europe (Rudolf Bertagnoli), North America (Scott Blumenthal), South America (Luiz Pimenta), Asia (Chun-Kun Park), Africa (Louis Nel), and Australia (Mathew Scott-Young). Lumbar TDR has been in use for more than 20 years.
Internationally, there are surgeons with high levels of experience with these devices and literature reporting good results, yet disc replacement has not gained universal acceptance as a treatment for painful disc degeneration. There are also reports expressing concern about wear debris and other complications.
The international panel of speakers described their experiences with various TDR devices, gave an overview of the literature, and discussed issues related to acceptance, or lack thereof, among surgeons and payers in their respective geographic regions. No one identified a problem with patient acceptance of the technology. Also included during the course was a presentation by a TDR recipient, Richard Longland, who for several years has managed a website dedicated to patient advocacy for TDR.
There was consensus that TDR produces good results in appropriately selected patients. This was noted in the long-term European experience and in the carefully monitored prospective, randomised Food and Drug Administration (FDA) regulated trials in the USA. There was general agreement that cervical TDR has gained acceptance more readily than lumbar, although lumbar has been used much longer. This may be attributable, at least in part, to cervical TDR’s application to treat conditions that are well defined and accepted in the spine community; whereas there remains some controversy over the diagnosis of painful disc degeneration, the primary indication for lumbar TDR. Ironically, for this reason and the inconsistent results of current interventions for lumbar disc degeneration may actually make it more important than its cervical counterpart where diagnoses and interventions are currently better defined. TDR may be of greater value in the lumbar spine due to the variability of results of other treatments for this condition. Of the presenters’ cumulative years experience with a variety of TDR designs for both cervical and lumbar applications, none have had a significant rate of device failures or re-operations related to device malfunction, migration, or subsidence. The primary keys to appropriate patient selection are patients with chronic pain related to disc degeneration, typically confirmed with discography, and who do not have significant facet joint degeneration, osteoporosis, or significant spondylolisthesis or scoliosis. As with most spine surgery, TDR complications can be avoided by adhering to appropriate patient selection criteria and using good surgical techniques to ensure good device positioning within the disc space and using the right size device to fit the patient.
Studies from several countries have found that TDR is similar in cost, or less expensive, than fusion for the treatment of painful disc degeneration.
Throughout the SAS conference, there were more presentations on prospective, randomised studies, five-year follow-up of additional FDA trials, and costs of TDR. These added more support to the favourable outcomes TDR achieved at costs less than or similar to fusion, and complications or re-operation rates that are similar to or lower than fusion.
The international TDR pre-course as well as other presentations during SAS10, reinforced the use of these implants in appropriately selected patients. There were no presentations with high device failure rates or complications greater than encountered with other surgeries to treat the same condition. The barriers to reimbursement for TDR seem to slowly recede; however, there is great frustration on the part of surgeons and patients that the procedure is still often denied in patients who meet selection criteria for it. Complicated and inconsistent reimbursement policies for TDR have created greater use of medical tourism both within and across the continents, particularly for self-pay patients.
Scott Blumenthal is an orthopaedic surgeon and partner at Texas Back Institute, Plano, USA.