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Thread: FAO HDugger - sorting out various fusions

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    FAO HDugger - sorting out various fusions

    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.
    Last edited by Pooka1; 08-30-2009 at 04:32 PM.
    Sharon, mother of identical twin girls with scoliosis

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    Just want to add w.r.t. the "well-corrected" claim... I posted a long-term study that showed no difference in pain levels between folks corrected somewhat versus a lot.

    So maybe there is some disagreement on that point.

    Also, there is no guarantee that fusions into the lumbar will cause disc issues. So there's that. For example, if my pain continues I would agree to a surgical extension of my natural two-level lumbar fusion just to be able to stand for any period of time. No question. I like doing fieldwork.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
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    "We are all African."

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    Quote Originally Posted by hdugger View Post
    Thank you so much, Pooka. That is *very* helpful. I'd been wondering why so many of the older adults who had surgery had it for double curves, when in young people it seemed that just the thoracic curve needed surgery. BTW, I wrote to the webmaster at the UofW site (because that's the only email address I could find). I'll let you know if I hear anything back from them.
    Linda (Racine, moderator) mentioned recently that it is sort of known or acknowledged or whatever that fusing earlier often means having to fuse less levels. That bothered me because I think it call into question waiting to get to 50* for T curves. Maybe these fusions could stop at T12 (or higher) rather than L1 or L2 if done earlier.

    Let me know if you see anything more about this kind of collapse, since it ties into my next question. What I've been wondering is, if one were able to keep their curve from progressing with exercise that it would also mean that the wedging would not increase. So, if my son were able to hold his curve at whatever it is now (variously measured anywhere from T47 to T57), he wouldn't suddenly come out of that to discover that his curve had gone to 80 degrees due to progressive wedging.
    Again, I hope Linda chimes in. I am guessing this particular type of relatively rapid collapse is unusual. What would not be unusual is the slow progression of both curves through life. I suspect the T curve would have progressed absent the collapse in the lumbar which was taking the brunt of the abnormal loading apparently.

    WRT you son being able to hold his curve at the present angle, I have no idea. Others here might know from personal experience. Certainly you would want him under constant observation and not just assume the exercises were holding the curve. It might be far more exercise than he realizes or even has time in the day to do.

    Also, does the wedging itself ever improve? So, for the two women who have managed to reduce their curves for many years with exercise, do their vertebra regrow to fill up that space? Or does only fusing cause the bones to regrow.
    I don't know but I'm guessing they have simply built up abnormally asymmetrical musculature to hold the vertebrae at a particular angle. I don't think vertebrae, once remodeled, can be modeled more correctly absent surgical intervention. And it's one thing to hold the curve; at least one of those women needed to exercise for 4 hours a day for several years to accomplish the reduction. And we don't know if she has been successful at holding the reduction or if she still needs to exercise several hours a day.

    I realize there probably aren't any firm answers on these question, but any information that would cast light in these areas would be helpful in our decision about how to proceed.
    I have come to realize there are many questions to which nobody knows the answer.

    BTW, I've gotten another recommendation for a Portland Dr. - Dr. Timothy Keenen, who's also on the SRS list of surgeons.
    It's good to start with a SRS surgeon though there are non-SRS folks out there doing as many or more scoli fusions with stellar results. Something to consider. SRS status requires devoting 20% of their practice to spine issues AFAIK. So you can find SRS guys who may have done few or no scoli fusions.
    Last edited by Pooka1; 08-30-2009 at 06:47 PM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by hdugger View Post
    Thanks again, Pooka. This will all be very helpful for him in making his decision about how to proceed.
    You're welcome but of course none of this substitutes for a few opinions from experienced orthopedic surgeons. It might be a good place from which to generate questions for the surgeons, though.

    Good luck.
    Last edited by Pooka1; 08-30-2009 at 08:56 PM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by Pooka1 View Post
    Linda (Racine, moderator) mentioned recently that it is sort of known or acknowledged or whatever that fusing earlier often means having to fuse less levels. That bothered me because I think it call into question waiting to get to 50* for T curves. Maybe these fusions could stop at T12 (or higher) rather than L1 or L2 if done earlier.



    Again, I hope Linda chimes in. I am guessing this particular type of relatively rapid collapse is unusual. What would not be unusual is the slow progression of both curves through life. I suspect the T curve would have progressed absent the collapse in the lumbar which was taking the brunt of the abnormal loading apparently.

    WRT you son being able to hold his curve at the present angle, I have no idea. Others here might know from personal experience. Certainly you would want him under constant observation and not just assume the exercises were holding the curve. It might be far more exercise than he realizes or even has time in the day to do.



    I don't know but I'm guessing they have simply built up abnormally asymmetrical musculature to hold the vertebrae at a particular angle. I don't think vertebrae, once remodeled, can be modeled more correctly absent surgical intervention. And it's one thing to hold the curve; at least one of those women needed to exercise for 4 hours a day for several years to accomplish the reduction. And we don't know if she has been successful at holding the reduction or if she still needs to exercise several hours a day.



    I have come to realize there are many questions to which nobody knows the answer.



    It's good to start with a SRS surgeon though there are non-SRS folks out there doing as many or more scoli fusions with stellar results. Something to consider. SRS status requires devoting 20% of their practice to spine issues AFAIK. So you can find SRS guys who may have done few or no scoli fusions.
    Hi Sharon...

    I would venture to say that 95% of the surgeons who are SRS members devote their entire practice to spine. The actual requirement is that members devote at least 20% of their practice to spinal deformity.

    --Linda

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    Quote Originally Posted by LindaRacine View Post
    Hi Sharon...

    I would venture to say that 95% of the surgeons who are SRS members devote their entire practice to spine. The actual requirement is that members devote at least 20% of their practice to spinal deformity.

    --Linda
    Ah okay. In that case, I don't see why they don't set the bar at 90% or better. Why do they set it so low?
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by Pooka1 View Post
    Ah okay. In that case, I don't see why they don't set the bar at 90% or better. Why do they set it so low?
    I've always wondered the same thing. The only thing I can think is that one of the missions of the SRS is to educate the medical community about scoliosis and other spinal deformities. I'm thinking that it's better to at least try to educate those spine surgeons who don't do a lot of scoliosis surgery, then to leave them floundering.

    --Linda

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    Thanks for posting that.

    I'm not sure that second clarification addresses T fusions. He seems to be talking about above the fusion and then mentions L1 and T12. That would mean that comment is about L fusions, no?

    So what is the bottom line on the possibility of degenerative changes above and below T fusions? I can't make it out from that response.

    Also, I never thought about the differences between adults who get fused for degenerative issues VERSUS kids who get fused who only have a curve and no degeneration. Maybe the jury is out on whether kids should be fused earlier when there are no degenerative changes. Maybe that obviates at least some of the changes or limits them to the levels immediately below (or above) the fusion as opposed to the rest of the unfused spine. Who knows.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by hdugger View Post
    I do have the sense that they just don't know how this newer instrumentation will turn out. But, yes, that gets to the "schizophrenic positions" about whether it's better to have them earlier or slightly later. The "slightly" was not a huge stretch. For both of the children, they were talking about waiting until they were in their 20s instead of operating on them at ages 15 (for the boy) and 13 (for the girl) if I remember correctly.
    When you are talking waiting "slightly" later, that might trigger the issue of longer fusion. It seems like with my kids, had they been fused earlier they might have had shorter fusions and stable backs but I don't know that. Shorter fusions being possible earlier is in keeping with what Linda stated also. So they are balancing whether or not a kid will progress with the length of the fusion essentially. I understand that in the case of AIS but if/when the situation clears up w.r.t. connective tissue disorder (CTD) scoliosis, I think it will be UNethical to let these kids get past ~35* if it means a much shorter fusion.

    Now w.r.t. waiting just 10 years later because a clock starts ticking on degenerative changes above and below the fusion, I'm still waiting on evidence that is true to T fusions as opposed to fusions into or within the L area. Again, Linda can comment again but it seems even with the older instrumentation, most of the problems triggering revision surgery are when the fusion extends into the lumbar or is in the lumbar. Hopefully, the new instrumentation will avoid that for those patients also.

    So while I can see the issues with waiting on an L curve which, by the way, has a lower chance of progressing to surgery territory compared to a T curve, I don't see any upside to not fusing a T curve as soon (or before in the case of CTD) it hits surgical territory. Or at least there is no evidence there is likely to be a problem over and above the 85% rate that the general public has of developing a back problem. I suspect that is why out surgeon seems to think my fused daughter is back in the same risk pool as everyone. Or at least the error bars on the long term T fusions might likely overlap the error bars for the general population so you can't show a difference thought one might be there. It's between 85% and 100% and the condition is very variable... that might be in the noise by definition.

    Who the hell knows?
    Last edited by Pooka1; 09-09-2009 at 03:29 PM.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by hdugger View Post
    There are concerns about long-term degenerative arthritis that may appear 30 to 50 years later in segments of the spine that were not fused. Currently, there is not adequate follow-up information on the procedure to know the frequency of this problem.
    I suspect that people with large unfused scoliosis curves are probably much more likely to experience degeneration than people with fused curves. I have, however, never seen any research that might confirm that.

    I could easily get a surgeon to answer questions, but I doubt that anyone would do it in a large forum such as this, as they'd be deluged with questions. If you have some interest in a conference call or a webinar, and someone has access to such a resource, I can probably provide a surgeon.

    Regards,
    Linda

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    Thanks so much for doing the leg work. I'll check it out.

    Do you guys have a preference for day/time of doing such a conference? Would a Sunday mid-afternoon work for example?

    --Linda

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    That fusion goes into the lumbar. Harrington rods are known to be problematic into the lumbar. It is my understanding, and Linda has agreed per her experience, that Harrington rods that are in the thorax only are not generally problematic.

    I don't know what causes instability above fusions but I don't think it is usual. I would like to know if that woman has some connective tissue disorder or other non-AIS scoliosis.

    I hope the pedicle screw constructs into the lumbar avoid the problems of the Harrington rods there. I think it is hopeful... some here have relayed that their surgeon gave them very low odds for having to extend fusions that go into the lumbar. I think it's because you can get the balance very good in all three planes with the screw constructs (and a great surgeon).
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Nope but it must be revisions/extensions to date in comparison to those with Harrington rods. I think peole were needing revisions/extensions only a few years out with H rods if they were fused very low. Perhaps that is already known not to be the case with pedicle screws. Who knows.

    I'm sure Linda knows.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Quote Originally Posted by hdugger View Post
    Yes, I'd be very interested in looking at any study with hard numbers for estimating the risk of revision with pedicle screws.
    Yes I would too. But I was told both my kids are not expected to need revision/extension because they had T fusions that end at L1. I'm guessing he is just extrapolating from the lack of problems with H rods in the T fusions and given the balance is even better with pedicle screws. That's my guess anyway.
    Sharon, mother of identical twin girls with scoliosis

    No island of sanity.

    Question: What do you call alternative medicine that works?
    Answer: Medicine


    "We are all African."

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    Hi...

    Unfortunately, there really aren't any truly long-term outcomes study yet. Although I'm sure that some adjacent level problems were seen in the early post-op period for Harrington rods, I don't know that any of the surgeons really understood the depth of the issue. Although it appears that surgeons believe there won't be any BIG issues like there were with Harrington rods, there's no way to know for certain. We do know that there are still adjacent level issues, but surgeons are getting better at knowing what causes those issues, and are starting to compensate for them.

    Anyway, here's a 3-year followup with a large cohort:

    Spine (Phila Pa 1976). 2008 Jun 15;33(14):1598-604.
    Operative treatment of adolescent idiopathic scoliosis with posterior pedicle screw-only constructs: minimum three-year follow-up of one hundred fourteen cases.

    Lehman RA Jr, Lenke LG, Keeler KA, Kim YJ, Buchowski JM, Cheh G, Kuhns CA, Bridwell KH.

    Walter Reed Army Medical Center, USA.

    STUDY DESIGN: Preoperative review of a prospective study, single institution, consecutive series. OBJECTIVE.: To analyze the intermediate-term follow-up of consecutive adolescent idiopathic scoliosis (AIS) patients treated with pedicle screw constructs. SUMMARY OF BACKGROUND DATA: There have been no reports of the intermediate-term findings in North America following posterior spinal fusion with the use of pedicle screw-only constructs. METHODS: One hundred and fourteen consecutive patients having a minimum 3-year follow-up (mean 4.8 +/- 1.1; range, 3.0-7.3 years) with AIS were evaluated. The average age at surgery was 14.9 +/- 2.2 years. Radiographic measurements included preoperative (Preop), postoperative (PO), 2-year (2 years), and final follow-up (FFU). A chart review evaluated PFTs, Scoliosis Research Society scores, presence of thoracoplasty, Risser sign, Lenke classification, and complications. RESULTS: The most frequent curve pattern was Lenke type 1 (45.6%), followed by type 3 (21.9%). The average main thoracic curve measured 59.2 degrees +/- 12.2 SD Preop, and corrected to 16.8 degrees +/- 9.9 PO (P < 0.0001). Sagittal thoracic alignment (T5-T12) decreased from 25.8 degrees to 15.5 degrees at FFU (P = 0.05). Nash-Moe grading for apical vertebral rotation (AVR) in the proximal thoracic curve decreased from 2.0 Preop to 1.1 at FFU (P < 0.0001), and AVR in the thoracolumbar/lumbar spine decreased from 1.6 Preop to 1.1 at FFU (P < 0.0001). Importantly, the horizontalization of the subjacent disc measured -8.3 degrees Preop which decreased to -0.9 degrees PO (P < 0.001). PFT follow-up averaged 2.4 years with a 7.1% improvement in FVC (P = 0.004) and 8.8% in FEV1 (P < 0.0001). SRS scores averaged 83.0% at latest follow-up. Age, gender, Risser sign, or complications did not have a significant effect on outcomes. There were 2 cases of adding-on, 3 late onset infections, 1 with a single pseudarthrosis, but no neurologic complications. CONCLUSION: This is the largest (N = 114), consecutive series of North American patients with AIS treated with pedicle screws having a minimum of 3-year follow-up. The average curve correction was 68% for the main thoracic, 50% for the proximal thoracic, and 66% for the thoracolumbar/lumbar curve at final follow-up.

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