Page 1 of 4 123 ... LastLast
Results 1 to 15 of 49

Thread: Average Progression rates

  1. #1
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901

    Average Progression rates

    In another thread I wrote:

    I am trying to understand the state of the art w.r.t. average progression rate. As I first understood our surgeon, he seemed to be saying if my daughter could stay below 50* at maturity, she would avoid fusion for life. I thought he meant that people below 50* at maturity simply don't progress ever. What I have come to learn from when I asked him to clarify is that folks still progress but usually at such a slow rate that they are not likely to need fusion in a normal lifespan.

    But I don't think that is accurate after reading the testimonials. What I think we hear is 1* - 2* per year for the average (WIDE variation) sub surgical case that is in the conservative treatment window (~25* - 50*) at maturity. But let's say a kid is at 35* at 15 y.o. and progresses 1* a year. That means they are surgical at age 30 on average. If they are 25* at 15 years old then they are surgical at 40 years old. And assuming a slower progression, it seems that many folks will be surgical by their golden years.

    As far as I can tell, all but the smallest curves that are below the conservative treatment range will reach surgical range well within a normal lifespan. And the 10 to 1 adult to adolescent fusion rate is consistent with that. What am I missing?
    I think I know what I was missing. I think the 1* - 2* degree a year progression rate is the average rate for folks over 50* AFTER maturity.

    I wonder what is know of the average progression rate for folks in the conservative treatment window (~25* - ~45*) after maturity. Whatever it is, it is certain to have a huge variability.

    It would be nice for someone to estimate the percentage of AIS cases that are associated with connective tissue disorders given at least some of these cases group away from the average AIS case. It would also be good to scrupulously try to not lump these two groups in these various research articles because each confounds the other if they truly represent distinct groups in terms of average progression rate. This is reason # 5,908,677 why this literature is dicey.
    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."

  2. #2
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    Here's an article...

    http://www.ijoonline.com/article.asp...13;aulast=Wong

    The natural history of adolescent idiopathic scoliosis

    Hee-Kit Wong, Ken-Jin Tan
    University Spine Center, University Orthopedics, Hand and Reconstructive Microsurgery Cluster, National University Health System, Singapore

    There have been great advances in the conservative and surgical treatment for adolescent idiopathic scoliosis in the last few decades. The challenge for the physician is the decision for the optimal time to institute therapy for the individual child. This makes an understanding of the natural history and risk factors for curve progression of significant importance. Reported rates of curve progression vary from 1.6% for skeletally mature children with a small curve magnitude to 68% for skeletally immature children with larger curve magnitudes. Although the patient's age at presentation, the Risser sign, the patient's menarchal status and the magnitude of the curve have been described as risk factors for curve progression, there is evidence that the absolute curve magnitude at presentation may be most predictive of progression in the long term. A curve magnitude of 25 at presentation may be predictive of a greater risk of curve progression. Advances in research may unlock novel predictive factors, which are based on the underlying pathogenesis of this disorder.
    Last edited by Pooka1; 08-24-2010 at 07:08 AM.
    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."

  3. #3
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    From that article (emphasis added):

    Curve Progression After Skeletal Maturity


    Once the child has attained skeletal maturity, it was generally thought that the curves are less likely to progress. However, this may not always be the case. It is now established that curves due to idiopathic scoliosis do not necessarily stop progressing after skeletal maturity. In a long-term follow-up study of patients with idiopathic scoliosis, Collis and Ponseti found that curves of a larger degree did increase after skeletal maturity. [20] In a separate study with an average follow-up of 40 years, Weinstein and Ponseti also found that a significant number of idiopathic curves increased after skeletal maturity. They reported that in thoracic curves, the Cobb's angle, apical vertebral rotation and the Mehta angle were important prognostic factors. For lumbar curves, the degree of apical vertebral rotation, the Cobb's angle, the direction of the curve and the relationship of the fifth lumbar vertebra to the inter-crest line were of prognostic value. However, they also observed that curves that were less than 30 at skeletal maturity tended not to progress regardless of curve pattern. [21]

    Given the varying definitions of curve progression, this suggests that curves with a Cobb's angle of 30 are an important threshold magnitude and may serve as an endpoint for prediction of curve progression rather than predefined units of curve progression quoted in previous studies. In addition, it must be appreciated that the various associated factors and predictions described only apply to the likelihood of a curve progressing in adolescence. They are only averages and correlations and do not allow us to answer the key issue of how much the curve of an individual child is going to progress.

    In a recent study, Tan and Wong reported on a group of 279 patients with idiopathic scoliosis detected by school screening, and who were followed-up until skeletal maturity using a 30 Cobb's angle at skeletal maturity as a threshold instead of predefined units of curve progression during shorter periods of growth. They found that an initial Cobb's angle of 25 was the most predictive factor for curve progression to this threshold magnitude. Initial age, gender and pubertal status were less important prognostic factors. [22] When different factors were combined, it was also possible to generate different risk progression profiles [Table 4].
    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."

  4. #4
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    By the way, here's another identifying initial Cobb at the most important prognosticating factor for progression, in agreement with other researchers. This is why the Katz et al. (2010) paper purportedly showing a dose-response in brace wear should have directly addressed the issue when interpreting their results. The groups were relatively small and may have been inadvertently stacked by chance. The researchers need to rule that in or out.

    http://journals.lww.com/spinejournal...iosis_.11.aspx

    Conclusion. Initial Cobb angle magnitude is the most important predictor of long-term curve progression and behavior past skeletal maturity. We suggest an initial Cobb angle of 25 as an important threshold magnitude for long-term curve progression. Initial age, gender, and pubertal status were less important prognostic factors in our study.
    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."

  5. #5
    Join Date
    Aug 2009
    Posts
    1,164
    Quote Originally Posted by Pooka1 View Post
    By the way, here's another identifying initial Cobb at the most important prognosticating factor for progression, in agreement with other researchers. This is why the Katz et al. (2010) paper purportedly showing a dose-response in brace wear should have directly addressed the issue when interpreting their results. The groups were relatively small and may have been inadvertently stacked by chance. The researchers need to rule that in or out.
    Aren't all of these researchers talking about a threshold Cobb (as opposed to the actual Cobb magnitude). I think this threshold of progression (25) is close to the threshold for bracing, so I'd suspect all of the subjects in the bracing study fell above it.

  6. #6
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    Quote Originally Posted by hdugger View Post
    Aren't all of these researchers talking about a threshold Cobb (as opposed to the actual Cobb magnitude). I think this threshold of progression (25) is close to the threshold for bracing, so I'd suspect all of the subjects in the bracing study fell above it.
    My point was rather that the magnitude of the curve at the beginning of treatment has been identified as an extremely important variable in trying to predict progression. That is, this is yet another way to restate that larger curves tend to get larger and smaller curves tend to stay smaller. On average. Katz et al. published what purport to be dose-response data (on mostly mature kids) for relatively small subgroups, each with different average hours of brace wear. Just like the results of an important previous bracing study were negated by the identification of unintentional stacking of L versus T curves in the treatment versus observation group respectively, I am saying Katz et al. should have triaged their data for inadvertent stacking of smaller versus larger curves in the various brace wear duration groups identified after the fact.
    Last edited by Pooka1; 08-24-2010 at 06:55 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."

  7. #7
    Join Date
    Mar 2009
    Posts
    1,090
    Quote Originally Posted by Pooka1 View Post

    I think I know what I was missing. I think the 1* - 2* degree a year progression rate is the average rate for folks over 50* AFTER maturity.

    I wonder what is know of the average progression rate for folks in the conservative treatment window (~25* - ~45*) after maturity. Whatever it is, it is certain to have a huge variability.
    The variability is not that huge. There is no doubt some variability between those with 45 degrees and those with 35 degrees and under after maturity.

    But for those with a 35 degree curve...none of these 92 patients progressed after maturity for at least sixteen years (except to return to the pre-braced angle, which is to be expected). There is no average progression rate for these patients, at least until in their thirties.

    "CONCLUSION: The curves of patients with adolescent idiopathic scoliosis with a moderate or smaller size at maturity did not deteriorate beyond their original curve size at the 16-year follow-up.

    Curve progression was related to immaturity."


    http://www.ncbi.nlm.nih.gov/pubmed/17873811

  8. #8
    Join Date
    Aug 2009
    Posts
    1,164
    Quote Originally Posted by Pooka1 View Post
    My point was rather that the magnitude of the curve at the beginning of treatment has been identified as an extremely important variable in trying to predict progression.
    Yes, I followed those discussions. I was just saying that that concern, stated in other discussions, didn't seem relevant to the results you cited in *this* discussion, since these papers are emphasizing a threshold of 25 degrees.

    On the rest, after a few years on this forum, I see the various interpretations of the scoliosis literature as a kind of Rorschach test - it illuminates the interpreter far more then the research.

  9. #9
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    Quote Originally Posted by hdugger View Post
    Yes, I followed those discussions. I was just saying that that concern, stated in other discussions, didn't seem relevant to the results you cited in *this* discussion, since these papers are emphasizing a threshold of 25 degrees.
    Yes that was not on point. I just added it here out of convenience because I found it in the course of working on this thread.

    On the rest, after a few years on this forum, I see the various interpretations of the scoliosis literature as a kind of Rorschach test - it illuminates the interpreter far more then the research.
    The range of interpretation among lay folks is not really relevant to anything. The range of opinion among researchers in this field and surgeons is what matters but only if they are up on the literature. Some apparently are not.
    Last edited by Pooka1; 08-24-2010 at 01:44 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."

  10. #10
    Join Date
    Sep 2003
    Location
    Northern California
    Posts
    6,797
    Hi Sharon...

    I suspect that the magnitude of curve(s) at presentation is important because 25-30 degree curves, which seems to be the size of curves when they're most commonly discovered, are the most successfully braced curves. That is, those kids don't progress to surgery by the time of skeletal maturity. However, as we all know way too well, we don't know if it makes any difference in the long-term outcome.

    --Linda
    Never argue with an idiot. They always drag you down to their level, and then they beat you with experience. --Dilbert
    I'm sarcastic... what's your super power? --Unknown
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    Surgery 2/10/93 A/P fusion T4-L3
    Surgery 1/20/11 A/P fusion L2-sacrum w/pelvic fixation
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    If you've signed up and are having trouble posting, please check your spam folder. An email was sent to the email address which you subscribed. You have to follow the instructions in that email. Done that and still having trouble posting? Contact Joe O'Brien at jpobrien@scoliosis.org.

  11. #11
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    Quote Originally Posted by LindaRacine View Post
    Hi Sharon...

    I suspect that the magnitude of curve(s) at presentation is important because 25-30 degree curves, which seems to be the size of curves when they're most commonly discovered, are the most successfully braced curves.
    Most successfully braced or most unecessarily treated? This is an open question as far as I can tell.

    Don't you think Cobb at presentation is important as a predictor because big curves tend to get bigger and small curves tend to stay smaller? That seems to explain most if not all of its prediction power.

    That is, those kids don't progress to surgery by the time of skeletal maturity. However, as we all know way too well, we don't know if it makes any difference in the long-term outcome.

    --Linda
    I hope some more studies come out on that. I think it will influence the bracing debate depending on how it shakes out. The ratio of adult/adolescent fusions will be relevant as will the average progression rate of curves at the low end of the treatment window in terms of if these folks are reaching surgical range in the out years. Twenty-five or 30* might be an important threshold here.
    Last edited by Pooka1; 08-24-2010 at 01:50 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."

  12. #12
    Join Date
    Mar 2009
    Posts
    1,090
    The Daniellson study had both braced and unbraced kids in it. Neither progressed after maturity for sixteen years. (And, in fact, only the non-braced kids progressed to surgery during the study.)

    Would I rather have decades of a non-progressing curve with full flexibility and the potential for amazing discoveries in the years ahead should surgery potentially be needed at some point due to multiple pregnancies or age-related deterioration?

    Or would I rather not brace and end up with surgery during adolescence and start the clock ticking on my revision surgeries due to age-related deterioration? And perhaps end up with a worse situation due to risks associated with that surgery to have to live with forever.

    That is a choice the parents and patients can make themselves...but I certainly know which one I would choose. Obviously some are going to progress even if braced, but that's a risk everyone takes with scoliosis until more is learned about the causes of progression.

  13. #13
    Join Date
    Aug 2009
    Posts
    1,164
    Quote Originally Posted by Pooka1 View Post
    The range of interpretation among lay folks is not really relevant to anything. The range of opinion among researchers in this field and surgeons is what matters but only if they are up on the literature. Some apparently are not.
    Given the quality of the literature, I'm not certain that "being up on it" is of much importance. Because of the lack of quality of the literature, any real scoliosis knowledge lies primarily in the land of anecdotal evidence. I'd trust an alert surgeon's anecdotal knowledge over a researcher who is familiar with the literature but hasn't directly worked with patients.

  14. #14
    Join Date
    Sep 2003
    Location
    Northern California
    Posts
    6,797
    Quote Originally Posted by Pooka1 View Post
    Most successfully braced or most unecessarily treated? This is an open question as far as I can tell.
    I was referring to success in the short-term. Kids with 30 degree curves usually get great correction if the brace is fitted well. I'm not talking about once brace treatment is discontinued, or success in the long-term.

    --Linda
    Never argue with an idiot. They always drag you down to their level, and then they beat you with experience. --Dilbert
    I'm sarcastic... what's your super power? --Unknown
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    Surgery 2/10/93 A/P fusion T4-L3
    Surgery 1/20/11 A/P fusion L2-sacrum w/pelvic fixation
    ---------------------------------------------------------------------------------------------------------------------------------------------------
    If you've signed up and are having trouble posting, please check your spam folder. An email was sent to the email address which you subscribed. You have to follow the instructions in that email. Done that and still having trouble posting? Contact Joe O'Brien at jpobrien@scoliosis.org.

  15. #15
    Join Date
    Jan 2008
    Location
    NC
    Posts
    8,901
    Quote Originally Posted by hdugger View Post
    Given the quality of the literature, I'm not certain that "being up on it" is of much importance. Because of the lack of quality of the literature, any real scoliosis knowledge lies primarily in the land of anecdotal evidence. I'd trust an alert surgeon's anecdotal knowledge over a researcher who is familiar with the literature but hasn't directly worked with patients.
    In the case of scoliosis bracing, being familiar with the literature is synonymous with realizing how much is unknown still. Claims that more is known than has been shown is to be unfamiliar with the literature.
    Last edited by Pooka1; 08-24-2010 at 01:46 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."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •