[Spinal instrumentation, source of progress, but also revealing pitfalls].

The second half of the XXo century and especially the last 30 years have been the source of a great improvement for surgical treatment of spinal pathology essentially in 3 directions:--First, for the patient himself and his comfort by suppression for most of the cases of any post operative external support thanks to the rigidity, security and strength of segmental fixation given by the hooks, screws and rods systems, as well for posterior as anterior instrumentation. In addition, these new techniques allow the patient to return quickly to standing and walking activity and subsequently the surgery for adult people increased dramatically especially for all kind of degenerative diseases and more and more extended spinal deformities.--The second major improvement came from the real and new understanding of the 3 dimensions for all the physiology and pathology of the spine leading to practical applications for the design and surgical strategies for correction. The exploding expansion of the era of computer technology brought a lot of help in such understanding as well as for the development of spinal instrumentation.--Finally the impressive development of medical imaging with CT scan and less and less invasive techniques like MRI allow a much better vision of spinal cord and roots (a major concern for the spinal surgeon). All this occurs also because simultaneous revolution occurred in the field of anesthesia and intensive care especially post operatively, but also because the big progress for monitoring of vital function as well as neurological monitoring during surgery. The consequence of that was an improvement for the results concerning the patient for functional quality of life as well as for cosmesis. The subsequent failures resulting of these improvements came from various fields even if we exclude infection or neurological complications more and more controlled now.--At the level of the indications because of these lack of post operative external immobilization, indication for cosmesis extend widely including adults. But also because these adult peoples are asking more and more for an active way of life including often sports. The indications for function also extend requiring more and more pre operative checking to limit the increase of the risk.--At the level of the pre operative strategy, most surgeons were establishing the strategy looking only on more or less close similar cases already done. In fact no personalized strategy done on biomechanical static and dynamic data of the patient as well as its connective and bone tissue proper qualities were really performed. It is why it is still now difficult to know pre operatively the behavior of the not fused area above and mainly below the instrumented area. Because the power of correction was very much improved with the new instruments, we can get some 3D imbalance immediately after or secondary acquired after such surgery as well from anterior or posterior devices. It is why we need pre operative simulation of surgery thanks to the computer.--At the level of surgery itself: it is not entered in the practical field any per operative 3D reliable measurement to know exactly the surgeon is doing because the maximum of reduction is not the optimum for many cases and this has to be quantified. The last thing is of course the difficulty to translate the lying position of the patient during surgery to the standing functional one. Some answers or perspectives for the future may come from:--The real pre operative simulation of the surgery (including levels of instrumentation amount of correction in 3D) according to the personalized values, stiffness, quality of soft tissues, weight, size, of the patient, localization and type of the deformity, etc.... Computer software already exists or are on the way to be expanded.--Per operative 3D control of what is doing the surgeon are also emerging with real time information in order to adjust the correction according to the pre op. simulation. In addition the noticed improvements on the biological field for fusion with bone activators like BMP, Hydroxyapatite, or bone substitutes like bio-active ceramics will probably help for fusion and decrease necessity of bone grafting. It is the same about disc regeneration which is on the way. Finally it is evident that the first steps already done for spinal surgery avoiding fusion will extend.--For children and growing spine, the challenge is major, but with memory metal instruments, laser precise destruction of abnormal growing structures as well as posterior flexible instrumentation avoiding stripping of the periosteum and leaving integrity of the disc and facet joints function, improvements are also on the way.--For adult and degenerative spinal deformities and pain, the development of spinal arthroplasty already done for the disc replacement will improve as well as for the posterior joints units where artificial ligaments experience will be replaced by real artificial joints still on experiment. In conclusion, some general biological medical questions are still waiting for answers:--Neurology and erect posture--Growth and degeneration--Malignancy (comprehension and control)--Pain and suffering. And of course what is the fact of the genetics for all of these problems: plenty of work for the future.