i was very happy to hear the first speaker because they have said almost everything i will show you the important for this topic is to not confuse alignment and violence and to to go to abundant balance because in human standing you know you must mixed alignment and balance one is static and the other is dynamic so on the x-ray when you see this patient the alignment is not so good but what about balance when you use the eos imaging system you have the advantage to see the patient not only front back but you see also the horizontal plane and it is very important to understand the importance of this horizontal plane you see when you see x-ray of this patient not so bad but your eyes are adapted to to to the instruments but when you see from the top and from the back and from the bottom it is not exactly the same and you see where the alignment is not so perfect so to simplify one of my fellow design the vertebral vector that you see here on the 3d vertebral vector able to quantify and you see the aspect of the normal spine of the right thoracic scoliosis pre and postop and when you say when you look to the same lengthy one group if you substrate put put them in various case you have you know the lumbar modifier the sagittal modifier described by larry but you need an horizontal modifier when you see this patient that was already treated with interspinous device and that was treated by transparticular osteotomies this was done by my friend jean-marc vitale in bordeaux when you see the view from the top demonstrates the good alignment but the balance with me judge only one motion and function we must get dynamic recording to get the mobility stability so you have the eos imaging system you have the force plate measurement and you have the dynamic motion analysis to have this dynamic evaluation of the balance and function because a balance static or dynamic is a stability within the movement you have to take it of course globally or locally remembering that global and local are permanent permanently linked sometime for worsening from time for compensation but think always that never treat one ignoring the other you have you know very well the complication cascade that can occur after only an herniated disc and uh it is evident that the eric posture in human is characterized by three major elements the chain of balance with cephalic vertebrae and horizontal gaze you have the the very big importance of the pelvic vertebra that can move and compensate as you see and this drive to the cone of economy of course that is a very important concept because the concept of the cephalic vertebrae you know the prosthetic to me and the swan neck deformity that you can get when you see this patient that was a congenital myomatic biopatty she was obliged to hold his head before the surgery of the spinal deformity uh by the hand after she was aligned correctly uh you see the head was holding by itself so the reverse pendulum concept is a very important as well as the concept of the vertebral pelvic vertebrae as a intercalary bone see the erect posture was acquired progressively during infancy in childhood the result of harmonious bonanza alignment during motion thanks to neurological input reflex and acquired automatis was learned during infancy and childhood it is the balance it is the [Music] balance and see if you're saying to this patient this child climbing the stairs you have the mechanical requirements the chain of joints in the space must work you have the muscle function antagonist and agonist strength power relaxation modulation speed acceleration breaking and the neurological requirement of course vision very important ent proprioception you have the modulation by coordination and double task with a condition that is a very important thing and you have at the end of the composite chain in the space the effector about speed transmission and and reaction so the global the first consequence is that the global balance is evidently neurological proprioception visual appearance and you you you see the tractography of the visual route when you see so many junctions inside the brain and of course a vestibulo labiantic efferents and here you see very well these very nice drawings that for me summarize the integrative centers that are from bine level mid brain level cerebellum spinal cord and the effector system the oculomotor system with the stabilization for the body and the gaze and the two second major conclusion is coming from the clinic that the disorder of this balance are often automatically correct by compensation you have the compensation very big characteristic of the human nature of biological metabolic and for example orthopedic level lumbar or doses compensate inflection contracture on inflation abduction of your shoulder contracerab a pollution defect and aging you see that with aging the pelvic reformation come but it is compensated by an inflection lumbar lordosis and you see this drawing very clear clearly demonstrate and remember also that the loss of extension of the hip joint has consequences been demonstrated clearly by islam overcast with a hip extension reserve it is why from time to time a total lip will resolve the problem of low back pain because it compensates moderate loss of the lumbar lordosis and this explains many immediate or secondary failures for example when you have a reflection contracture of course you have the change of the orientation of the pelvis so remember the hip extension reserve is important each person has a specific morphotype of the spine in it and you you know why the incidence angle was described by madame du divalbo and you you know very well the fourth sagittal type of the spinal alignment in the population uh as it is one of the factors of the chain of balance with his big genetic penetrance that you can get and remember that this is not always the incidence angle may change and you you saw we did an experience for 30 idiopathic sclerosis a fuse only on the thoracic area down to a a l1 or l2 maximum and when we measure the posture and the movement after the fusion we see that it was a change very important and go going to showing that the compensation come from the movement of the pelvic vertebra and we saw in this survey that 50 percent of the case had a modification of the pelvic angle incidence angle up to 11 degrees so the real question of of the balance is a question of the piling of the body regarding the gravity exceeds axis but mainly of the mass the mass not only of the angle so because the head torx abdomen pelvis are mass and the ignorance of the concept was explaining many of uh failure that you can get because you have a calculation only on the projected angle not on the mass and for example this uh transparticular osteotomy would not survive sagittal alignment but you you will know the result on the balance not immediately on the x-rays that yet you show but it is taking count the afferents the integration the effector below in between above and uh so remember that it is necessary and it was already said very clearly and the last speaker demonstrates the importance of all the brain function to to test the the reason a long time ago uh in in 2002 uh 2011 something like that in miami i describe the spine like a statue it is this long instrumentation when you see here and when you do that you have a very high risk you have only motion at the cervical thoracic and at the hip junction it is why in many cases you see this so-called pgk and a pelvic junction failure and when you have this this ad for example if in your plan you do too much lumbar lordosis you remember you you see that your upper part of the of the of the spine is pull on the back and after to recover a [Music] gravity line it is necessary to have a pgk so it is due to the spinal imbalance of the head of the mass of the head so don't be addicted by the angle think about mass it is important a persian okay for this not a question of scroll why ligament connector everything it's a comprehension of the chain of balance uh local balance of the sephalic so why why is this occur because the the pre-op where we're done purely static with ignorance of the amplitude and uh to to know exactly the possibility of compensation above and below the fusion zone and when you ignore the mass of the head and the torx of the pelvis and lower you you you you are looking on on the pure pure projection of the alignment but you don't know about the exact active possibility so you need some to to to measure this uh this dynamic you have to make coupling of the uh aoc imaging uh of the reconstruction of the of the measurement of the force plate to to try to approach the the dynamic balance in the spain in the spy in the space and to approach this cone of economy that i described long time ago because you see for example for for for this patient you you follow with time the patient and it is very useful for aging people that with time you have extension amplitude of of the spine very almost symmetrical to the amount of flexion and slowly and slowly you keep flexion good but you you lose amplitude of extension and with the time you you you become unbalanced then critical then overstep so it is necessary to try if you follow this very clearly to choose the time to do surgery before not only as a cardio treatment or a etc function disappear but also to to try to to do the surgery before too much correction it is why it is necessary to measure this was already said by previous speaker but i i will emphasize this to measure the in standing as well in lying proposition the active movement a total segmental head cervical spine spine and also at the same same level same thing ip join to keep the possibility of adaptation and compensation so prevention for for me four factor very important never stop the upper instrumentation of the junctional vertebra because the junctional vertebra is always the most instable and you shave the you check the active pressure band bending add upper thoracic spine including the scapular girdle with humeral heads you check the lumbar column if you in your plan you you you remember spine is not be planed not be planned to to be fused you must check the active lumbar lordosis of the patient and if you have to fuse down to the sacrum you must check also the amount of lordosis and then the incidence angle have some importance but never forgot the hip extension reserve that is as important in passive or in his acting and this is it's easy and and uh when you have a research lab when you have all the tools but you don't have this in in your in your clinic easily so for me it's an important thing to check the patient with a simple chronometer uh you can do this in in your clinic speed and walking five meters straight forward backwards speed and ease to climb three stairs and go down and for me the most discriminant it's a speed and ease to squat on the floor and get up but never forgot to make this uh very easy testing is working while you are speaking on the telephone or for example use being one two three or you you was being uh ninety ninety one with one with two with three and and you have the double task that's give you an idea of the condition of the patient so never forgot this so for me you you must check your your planning that is what said uh even for the post-operative evaluation not only on static picture on x-ray but on the dynamic measurement for me the dynamic balance in the space is okay for the longevity of the spinal unit remaining and you remember that i i did this drawing for the cd instrumentation in 1983. i want that i demonstrated on the sagittal plane here but you have to to think that is occurring in the three dimension to get the balance the unbalance in one direction or in other words so you must uh have the bone engine status alignment with me the muscle power and this is important and the coordination with a neural system neurological system with a vision vestibular proprioception coordination and the efferent and you have to to check this to every of your patients becoming slowly and slowly hold as soon as 45 years old and then to prevent this you can have proper nutrition of course if you have to do surgery at that time is necessary of course to do you make the correction of the various levels after you are you must have daily physical exercise sufficient in time and and intensity not performance but exercise and you have of course to have your control and correct vision and especially good good foot shoes and physical exercise we instilled that direction proprioception and vestibular and never forgot the cognitive rehabilitation with double tasks and of course be very careful and this was said also by gents at the beginning as a first talk be careful with the medical drugs of course that changes and aging does exercise as some influence on the result and you must remember this work in 2013 for a big number of patients with a mean age 76 year old people half were doing daily exercise balance station and the other half was not doing such exercise and in the in the case that were exercise group 40 percent less fall and 61 percent less fracture in the exercise group and we did a meeting at the a national academy of medicine about the muscles in uh january 2018 and we demonstrate here clearly that the satellite cells are able to activate and multiply in the muscle uh of course when you are very young you have 45 65 division at five year old and but you are still at 15 you have still that central year but even at 80 year old even 86 year old you have still divisions demonstrating that of course exercise is very important so don't mix don't don't uh remember that you you you are not too to to to speak about balance when you say an x-ray alignment and balance are very very important thing they are not opposed they are complementary a good alignment is preferable to have a good balance but not sufficient it needs a 3d balance of course just in 3d with the polygon of support or with entire chain of balance but also needs compensation passive and active and big need the reaction action reaction on the neurological point of view this is the result of the balance and remember that with jean-pierre farci a long time ago we we say that aging starts on your birthday and a good health for elderly is prepared during childhood and afterward so you have so many things that entering on the balance mechanics earring vision emotion vestibule proprioception thalamus hormone and bone and nail function so it is only the the message that don't mix alignment and balance thank you