Spinal arthroplasty is here to stay: editorial

Abstract

The authors of this review [1] are to be commended for thediligence they displayed in compiling an overview on theexisting literature regarding spinal arthroplasty. Especiallyhelpful and on the positive side are the tables summarisingthe results of current randomised controlled trials (RCTs),which is very informative for the readers.The information in this review serves the purpose toprovide that part of our neurosurgical community, which isnot intensively familiar with this topic (especially lumbartotal disc replacement (TDR)) with a modern, condensed,and balanced view on it, plus an outlook that will mostprobably happen with this technology.As such, this review should provide additional and newinformation if compared with earlier reviews on this topic(i.e. [2, 3]). In this regard, the literature search isincomplete, as the authors state themselves. The reasonfor this is not quite obvious for me, because it is not veryinspiring to just reiterate known facts and uncertainties.While I agree with many things, I am also happy tosupplement some additional information I feel necessaryplus a somewhat different interpretation of several relatedissues. I hope the authors, who had a tremendous task, willconsider this as normal within the process of peer review,because I am to express opposing views on a number offacts. There is no absolute truth for most things in medicineas there would be in a simple black and white world; thereare merely different shades of grey, with my “grey” havinga different hue. It will be up to the individual reader todecide.My first problem is a certain lack of focus on the actualtopic, i.e. total disc replacement, which is absolutelynecessary because of the sheer amount of information ondisc protheses alone, especially if one likes to cover lumbarand cervical together. The authors go astray and comment“en passant” on related nonfusion technologies (by the way,most people will consider this expression as the genericterm for these technologies).As such, they comment on interspinous devices (IPDs)and nucleus replacement. While they state that the former“has been abandoned due to bad results”, they reserve a lotof space with a more positive tone for the latter. However,reality is in sharp contrast to that, and the literature clearlygives a completely different picture. So this statement isfounded on nothing but personal preference and gut feeling.Whether one likes it or not, IPDs are in widespread andunfortunately uncontrolled use in many countries. Furtherand more important, several IDE studies are going on in theUS as well as multicentre RCTs in Europe to provenoninferiority to decompression, i.e. the standard treatment.We will see, thereafter, where the place for IPDs will be. Sofar, one can only state that they are widely used for theirease of implantation mainly, but also for the wrongindication in many instances. This does not discredit thetechnology, but the user instead. Above that, IPDs are thoserare devices that were introduced subsequent to a proof ofnoninferiority to conservative treatment (i.e. [4–6]). Notmany technologies in spine surgery were and are scruti-nised in this manner. This holds especially true for nucleusreplacement. Not a single good quality report can be foundin the literature. It has disastrous results and must beconsidered absolutely experimental. The only correctattitude to this theoretically attractive concept is a stepback to the laboratory (i.e. [7]) and start a carefullydesigned clinical trial thereafter.