Minimally Invasive Spine Surgery

Minimally or less invasive surgical techniques have profoundly changed the way surgeons operate today. Never before in medical history have surgical procedures undergone such tremendous and often even fundamental changes in such a short period of time as we have seen in the last 2 decades. Technology rapidly changes our daily lives outside of the surgical environment, triggered by the increases in computing power, advances in information technology and progress in material sciences, to name just a few. Driven by the same scientific and engineering forces, the superior intraoperative visualization techniques provided by modern microscopes and endoscopes, the improved materials in spinal instrumentation and the new image-guided procedures have had and still have a profound impact on the way we operate today.

Why did we develop newer and less or even minimally invasive techniques in the first place?

The answer is simple: to facilitate the patients’ return into normal life as fast as possible with the least possible surgically associated morbidity. But does this also mean that minimally invasive surgery or especially minimally invasive spine surgery (MISS) is less demanding or even less dangerous?

Here a fundamental problem surfaces: who has not been asked by a patient whether a specific procedure can be done in a minimally invasive way? From the patients’ point of view minimally invasive mainly means less dangerous. Unfortunately some of us try to sell exactly this idea to our patients. It is my personal opinion – which I share with most of my spine surgeon colleagues – that minimally invasive techniques are certainly not less dangerous. We need to achieve the same surgical result, e. g., an internal fixation or the removal of a fragmented disc using a drastically reduced exposure which concomittently results in a drastically reduced visualization. The 2D view through an endoscope can certainly never equal the sharp brilliance of a 3D image provided by a modern surgical microscope. Another problem is the reduced manipulatory options. Operating through one working channel is doubtlessly more demanding than performing the same procedure with 2 hands.

When using minimally invasive surgical techniques, we have to achieve the same surgical results with limited visualization and fewer manipulatory options as those in conventional, open approaches. These problems can partially be overcome by the rigorous use of modern surgical technology, such as high-definition cameras and flexible endoscopic instruments. The benefits are reflected by the fact that most studies comparing minimally invasive with standard techniques show comparable complication rates in traditional vs. minimally invasive procedures. It needs to be emphasized that, generally speaking, the long-term outcomes tend to be equal for the 2 surgical techniques.

The main advantage postulated and proven in a variety of studies for at least some procedures, such as mini open PLIF, is the reduced hospital stay and the faster recovery of patients operated by means of MISS.

However, many of these less or minimally invasive technologies are still lacking proof for less comorbidity and better short- or long-term outcomes on the basis of evidence-based studies. In order to successfully integrate and use these techniques, solid and well planned studies are required to define and prove their value in comparison to standard techniques.

The work of Arts and his colleagues has sparked an interesting debate and some, in my opinion, necessary controversies. It is a well planned, multicenter study with a result that does require some thought and it has most certainly stirred up the community of spine surgeons.

In my personal opinion, the exposures required for a “conventional” microsurgical approach compared with a tubular procedure in this particular pathology of lumbar herniated discs are quite similar. Not surprisingly the results are also quite similar. The study does not show a significant advantage of one method over the other concerning this particular operation. However, this should not lead to the conclusion that tubular procedures in general do not yield benefits in terms of faster patient recovery. Especially in more complex cases, this method will probably show its benefits – which will still require the proof of scientific data.

Mainly, it underlines the necessity of such studies concerning minimally invasive spine procedures. However, as a personal opinion regarding the study mentioned above, I do believe that it not only demonstrates the need for additional and similar carefully planned studies, but also the need for good evidence-based data.

We must have such evidence-based data in order to continuously evolve even better techniques without being overwhelmed by the ever-increasing progress of technological possibilities and their promises. We belong to the first generation of surgeons facing technological promises and possibilities like never before. With this comes responsibility. It depends on us to shape the future of surgery, and therefore we need more scientific data and studies investigating our new methods.

Or as the Antoine de Saint-Exupery wrote: “As for the future, your task is not to foresee it, but to enable it”. We should act accordingly.

Correspondence