Thursday, July 29, 2010
From the Desk of Peter G. Whang, M.D.
My name is Peter Whang and I am one of the members of the Evidence Based Medicine (EBM) Editorial Board who has been asked by Spine to evaluate several of the most important studies in the field of spine surgery that have been published in prominent journals over the past 6 months and develop recommendations for clinical practice based upon a critical assessment of the available evidence. I hope you have had the opportunity to read our most recent installment which was published in the July 1 issue of Spine. The primary purposes of this article were to summarize these studies, perform a methodologic review in order to elucidate their relative strengths and weaknesses, and determine if these results justify any changes in the so-called “standard of care” for spine surgery.
My fellow members and I consider The Spinal Column blog as an opportunity to receive direct feedback from the readers about this process and to discuss the conclusions we have drawn from each of these investigations, many of which are bound to be at least somewhat controversial. For instance, we analyzed two prospective, randomized trials comparing vertebroplasty to a sham procedure (Buchbinder et al. and Kallmes et al.) that were published together in The New England Journal of Medicine last year.1,2 Although these studies appear to provide Level 1 evidence suggesting that vertebroplasty does not confer any significant advantages over placebo, both studies exhibit significant limitations which we felt did not warrant the complete abandonment of this treatment option for vertebral compression fractures. From my experience with cement augmentation largely involving kyphoplasty (which was not specifically addressed in these clinical trials), I would maintain that patients clearly experience rapid and significant pain relief which I believe is more favorable than the natural history of vertebral compression fractures. This is an example of “cognitive dissonance” – how could this procedure be no better than placebo if patients do so well? Nevertheless, regardless of my personal feelings, it is these types of studies which need to be completed in order to definitively establish the efficacy of these interventions.
I also believe that the results of the Abdu et al. investigation comparing various fusion techniques (i.e. in situ posterolateral, instrumented posterolateral, or 360°) for degenerative spondylolisthesis using data from the Spine Patient Outcomes Research Trial (SPORT) to be quite fascinating.3 While there were some initial improvements in SF-36 bodily pain and physical function scores at 2 years with circumferential constructs, there were no significant differences noted between any of these cohorts after 4 years. Proponents of interbody arthrodesis cite many potential advantages such as the ability to achieve greater reduction and anterior column support which are thought to bring about enhanced radiographic and clinical outcomes; however, it does not appear as if these benefits are borne out in the existing literature at this point. We are certainly not suggesting that 360° fusions are not indicated for this application but are simply pointing out that there continues to be a paucity of Level 1 data that is able to differentiate between these different methods. Thus, for the time being it seems as if there are still many ways to “skin a cat” when it comes to treating degenerative slips. The SPORT study has generated some of the highest-quality evidence that has ever been published in this field.
Have any of these findings actually influenced the way you manage your patients?
Let’s hear your views and experiences. Please post your thoughts on The Spinal Column.
- Buchbinder R, Osborne RH, Ebeling PR, et al. A randomized trial of vertebroplasty for painful osteoporotic vertebral fractures. N Engl J Med 2009;61:557-68.
- Kallmes DF, Comstock BA, Heagerty PJ, et al. A randomized trial of vertebroplasty for osteoporotic spinal fractures. N Engl J Med 2009;361:569-79.
- Abdu WA, Lurie JD, Spratt KF, et al. Degenerative spondylolisthesis: does fusion method influence outcome? Four-year results of the spine patient outcomes research trial. Spine 2009;34:2351-60.