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  1. #1
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    six degree curve

    I am new to this part of the forum. I am recently recovering from my own surgery. I have watched my own children like a hawk, but surprisingly, my daughter was diagnosed with a 6 degree curve this winter. She is 14, has stopped growing and the doctor said that they wouldn't have done anything for her anyway.

    My concern is: I was told as an adolescent that after bracing my curve would not progress. My curve was much larger than hers. But does anyone have any information on adolescents with small curves and their chance of progression? My heart would break if she had to go through what I have been through.
    Kathy, 43
    Diagnosed as a teen
    Boston brace 2 years
    63 degree lumbar curve
    Surgery August 26, 2009
    Anterior approach fused T12-L4
    now 28 degrees

  2. #2
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    Hi Kathy,

    I don't have the link to the chart handy (there's one that shows the likelihood of progression based on the size of the curve when discovered), but my memory is that a 6 degree curve is extremely unlikely to progress in a teenager who has stopped growing. I'm not even certain it can be diagnosed as scoliosis if it's under 10 degrees - most people have some small degree of curve.

    I completely understand your concern, but I think it's very likely that she's safe.

  3. #3
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    Take a deep breath there Kathy, I think your daughter is in pretty good shape.
    The only actual data I can share to support that is the attached figure (maybe others can cite other supporting information).
    Using the lowest curve amplitude (10 degrees) and figuring your daughter's skeletal age is Stage 3 or above (likely above), the table indicates a 0% liklihood of progressing to surgery (I know that (surgery) wasnt your question, but this is the only data I have to share).
    The 95% confidence intervals are very small (0 to 0). Pretty good.
    Now yourself on the other hand, after bracing, likley fell into one of the ranges lower on the graph (with much more vague confidence intervals).
    In life nothing is guaranteed, but I think there is a vanishingly low chance your daughter will go through what you did.

  4. #4
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    Fascinating...it just shows how much need for further research we have to do. Wide variations where they had too small a sampling...

    People my age and older are realizing that what we knew years ago is nothing compared to what we know now. After I took my brace off, I thought nothing of it until 1 year ago, when I noticed how disfigured I was. My doctor thirty years ago was Wood Lovell, who was a champion in the field of pediatric orthopedics...and still we've come so far.

    Thanks so much for the info. I will rest easy...but keep a close eye!
    Kathy, 43
    Diagnosed as a teen
    Boston brace 2 years
    63 degree lumbar curve
    Surgery August 26, 2009
    Anterior approach fused T12-L4
    now 28 degrees

  5. #5
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    Quote Originally Posted by concerned dad View Post
    Take a deep breath there Kathy, I think your daughter is in pretty good shape.
    The only actual data I can share to support that is the attached figure (maybe others can cite other supporting information).
    Using the lowest curve amplitude (10 degrees) and figuring your daughter's skeletal age is Stage 3 or above (likely above), the table indicates a 0% liklihood of progressing to surgery (I know that (surgery) wasnt your question, but this is the only data I have to share).
    The 95% confidence intervals are very small (0 to 0). Pretty good.
    Now yourself on the other hand, after bracing, likley fell into one of the ranges lower on the graph (with much more vague confidence intervals).
    In life nothing is guaranteed, but I think there is a vanishingly low chance your daughter will go through what you did.
    There is something funny about that table... there are huge jumps between small probabilities (shaded) in each and every column and then a huge probability (unshaded). That suggests a real physical threshold at each combination of maturity stage and Cobb angle which strains credulity. You would expect a smoother distribution I think with no sharp thresholds, especially at each stage. It almost can't be right and must be an artifact of extremely small sample sizes in the face of what is known to be a wildly variable condition.

    If those data are to be believed, someone should be looking specifically for some physical reason each of those combinations should have a huge probability jump at some point. That might be an important clue if real (which I don't think it is). You can fool yourself with large data sets... it's not unusual to fool yourself with small ones. This is very difficult research.

    For example
    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."

  6. #6
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    Quote Originally Posted by Pooka1 View Post

    For example
    WOW! I lost my train of thought there and I can't now figure out where I was going with that!

    The neurons... they peter out...
    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
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    Sharon, you make a valid observation. I neglected to include the specific discussion the author made in the text. I did note though that the researchers intent was not so much to assess likelihood of curve progression, but rather to assess the predictive power/utility of skeletal maturity indicators in that determination (edit, I just reread my post, I guess I didnt "note" this. Oh well, I should have).

    The risk of progression is determined with use of logistic regression methods. The estimated probability of the final curve being >50 degrees for Lenke type-1 curves (single thoracic curves) and type-3 curves (double major curves with a predominant thoracic curve) is shown in Table III. The average risk of progression is that determined by logistic regression. Where there was no corresponding data point, a logistically created one was added so that the probability could be estimated for all combinations of main curve magnitude and maturity stage. The 95% confidence intervals are shown in parentheses. Wide confidence intervals reflect a small sample size, indicating that the probability may require modification with a larger sample, and therefore those particular cells should be interpreted with caution.

    Table III shows the relationship between maturity stage, curve size, and the probability of the curve progressing to >50.The unshaded cells correspond with combinations for which surgery would be a plausible treatment if >50degrees at maturity is accepted as a threshold for surgical treatment. For example, if a patient presents with a 25 degree curve, the prognosis would clearly depend on the maturity stage of the patient. For stages 1 and 2, surgery is quite likely; conversely, for stages 4 to 8, surgery is unlikely. For Stage 3, the probable outcome is not so clear.

    As shown in Table III, a 25 degree curve had substantially different chances of reaching 50 degrees, depending on the skeletal maturity stage. Since stages 1 through 5 all typically occur before iliac apophyseal ossification, a 25degree curve in a girl who is in Risser stage 0 and skeletal stage 2 has a 100%(confidence interval, 92% to 100%) chance of reaching >50 degrees despite bracing. On the other hand, the same 25degree curve in a girl who is in Risser stage 0 but skeletal stage 4 has an essentially 0% (confidence interval, 0% to 5%) chance of reaching >50 degrees. A 25 degrees curve in a girl who is in skeletal stage 3 has a 29% chance of reaching >50 degrees, but the confidence interval (3% to 84%) is too wide for accurate estimation. To predict the probability of the curve being >50degrees to within 10% (with 95% confidence), a power analysis suggests thirty-six or more patients must be followed through to skeletal maturation for each curve type.


    There are other caveats the author reports in the paper and we should be cautious to try to read too much into this chart. It is the only recent study that came to my mind to address Kathy's question. There may be better/more relevant information. Sharon, I know you like to see confidence intervals reported. You must be pleased to see them included in this research. The “take away message” from this data is the stuff I bolded above for emphasis. I think this is the information he wanted to get across. Risser 0 is NOT the important thing. The important thing is skeletal maturity stage (as assessed from an xray of the hand).

    I am also attaching Table 1 from the same paper.
    Last edited by concerned dad; 10-18-2009 at 11:24 AM.

  8. #8
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    Quote Originally Posted by concerned dad View Post
    The average risk of progression is that determined by logistic regression. Where there was no corresponding data point, a logistically created one was added so that the probability could be estimated for all combinations of main curve magnitude and maturity stage.
    Well I have my standard "what isn't linear on a log-log plot?" comment?



    To predict the probability of the curve being >50degrees to within 10% (with 95% confidence), a power analysis suggests thirty-six or more patients must be followed through to skeletal maturation for each curve type.
    That's interesting. Close to but larger than 30 which is some magic number in stats.

    Sharon, I know you like to see confidence intervals reported. You must be pleased to see them included in this research. The “take away message” from this data is the stuff I bolded above for emphasis. I think this is the information he wanted to get across. Risser 0 is NOT the important thing. The important thing is skeletal maturity stage (as assessed from an xray of the hand).
    Well me and anyone who wants to know how precise the data are like error bars.

    I tried to graph those data in Excel with the error bars and also for the +/- 5 degree error on the angle but I couldn't do it. I need by scientific graphing package at work. But I got far enough to guess why they tabled the data rather than graphed it.

    Interesting. This stuff is very hard to do.
    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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