Continuing in response to your posts on the Autism thread, this post from the blog of an SRS surgeon seems relevant to the issue of postulated long-term outcomes.
This woman had a T/L of 30/18 at maturity and in less than 20 years had a T/L of 30/39! In other words, her T curve held but her L curve went up more than a degree a year.
He makes a case for earlier fusions that likely may prevent collapses as seen in this case but I wonder how common these collapses are.
It also addresses the issue of long-term stability of the lumbar discs when the fusion ends at L1 or L2 that is relevant to your earlier comments.
Progressive scoli despite 30* T curve at maturity
Could earlier scoliosis have prevented this lumbar collapse? Probably yes. With modern current scoliosis techniques using pedicle screw fixation, and shorter constructs for thoracic curves (T5-L1 for example), 80-95% corrections are possible of the major curve, which results in nearly complete correction of the compensatory curves on either side, including the lumbar area. Although there can be an issue with adjacent level failure with lumbar fusions, it appears that the patients who have thoracic fusions down to L1 or L2, with most of the lumbar discs preserved actually wear their lower lumbar discs very well, especially when the top curve is well-corrected. Perhaps in the future we will have more longitudinal studies which will show that earlier short fusions can prevent the later collapse of the upper and / or lower curves that tend to affect quality of life a lot in the adult population. In this case, a “stitch in time may save nine”, in that a smaller operation can be performed on the adolescent or young adult which prevents the need for a longer instrumentation and fusion later in life to fuse across both the upper and lower curves. This younger age may also allow for a greater degree of correction, with subsequent improvement in load balance, and by fixing it at a younger age allow the discs to be subjected to more centered loads for the duration of the life of the person.
All things considered, I am thinking my unfused kid might have benefited more from being fused when she hit 40* rather than now but it probably won't make a difference to the outcome.
My fused kid followed the trajectory in the blog... T curve corrected from 58* to 5* and the lumbar curve straightened completely on its own. I hope for the same with my other kid.
This woman had a T/L of 30/18 at maturity and in less than 20 years had a T/L of 30/39! In other words, her T curve held but her L curve went up more than a degree a year.
He makes a case for earlier fusions that likely may prevent collapses as seen in this case but I wonder how common these collapses are.
It also addresses the issue of long-term stability of the lumbar discs when the fusion ends at L1 or L2 that is relevant to your earlier comments.
Progressive scoli despite 30* T curve at maturity
Could earlier scoliosis have prevented this lumbar collapse? Probably yes. With modern current scoliosis techniques using pedicle screw fixation, and shorter constructs for thoracic curves (T5-L1 for example), 80-95% corrections are possible of the major curve, which results in nearly complete correction of the compensatory curves on either side, including the lumbar area. Although there can be an issue with adjacent level failure with lumbar fusions, it appears that the patients who have thoracic fusions down to L1 or L2, with most of the lumbar discs preserved actually wear their lower lumbar discs very well, especially when the top curve is well-corrected. Perhaps in the future we will have more longitudinal studies which will show that earlier short fusions can prevent the later collapse of the upper and / or lower curves that tend to affect quality of life a lot in the adult population. In this case, a “stitch in time may save nine”, in that a smaller operation can be performed on the adolescent or young adult which prevents the need for a longer instrumentation and fusion later in life to fuse across both the upper and lower curves. This younger age may also allow for a greater degree of correction, with subsequent improvement in load balance, and by fixing it at a younger age allow the discs to be subjected to more centered loads for the duration of the life of the person.
All things considered, I am thinking my unfused kid might have benefited more from being fused when she hit 40* rather than now but it probably won't make a difference to the outcome.
My fused kid followed the trajectory in the blog... T curve corrected from 58* to 5* and the lumbar curve straightened completely on its own. I hope for the same with my other kid.
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