Page 4 of 5 FirstFirst ... 2345 LastLast
Results 46 to 60 of 63

Thread: Flexural-torsional buckling

  1. #46
    Join Date
    Jan 2008
    Location
    NC
    Posts
    9,184
    Quote Originally Posted by sjmcphee View Post
    btw, Also note I was skeletally mature at the time of that xray, so I never had factors relating to growth as a part of my scoliosis.
    Have you considered that you injured yourself there only because there was a small curve there already?

    I suggest it might be physically impossible to pull your spine into a T3-T6 12* curve from using your arms and getting injured from that.
    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. #47
    Join Date
    Nov 2010
    Location
    Los Angeles
    Posts
    139

    3D x-rays

    Sorry to change the subject but this discussion has me wondering about 3d x-rays. I get that by building a 3d model, it would have all the flexibility of a living spine. But I'm also wondering why more 3d x-rays of actual spines aren't taken. I recently had a 3d x-ray taken at the dentist. If you haven't seen this, it produces a 3d model that looks like the bottom half of your skull and jaw. It also produces something that looks like a regular x-ray but can be dragged to view from any angle. Do they do this on spines too? It seems like you could get a better view of the rotation and even start to develop better ways to quantify curves other than just Cobb angle. The only thing I've seen along these lines for scoliosis is what looks like a topographical map of your back so you can see the rib hump, etc, but still only from the one viewpoint.
    1993, Age 13, 53* Right T Curve w/ Left L compensatory
    2010, Age 30, 63* or 68* (depending on the doc) Right T Curve w/ Left L compensatory

    http://livingtwisted.wordpress.com/

  3. #48
    Join Date
    Mar 2010
    Posts
    2,004
    Mehera, I think you are refering to CT. But radiation seems to be hundreds times greater..

  4. #49
    Join Date
    Nov 2010
    Location
    Los Angeles
    Posts
    139
    I don't think it was a CT scan. I should have asked them more about it. Just googled and it looked a lot like this: http://www.youtube.com/watch?v=SxPljWm3vGA
    1993, Age 13, 53* Right T Curve w/ Left L compensatory
    2010, Age 30, 63* or 68* (depending on the doc) Right T Curve w/ Left L compensatory

    http://livingtwisted.wordpress.com/

  5. #50
    Join Date
    Mar 2010
    Posts
    2,004
    A CT give a 3d image of the spine. I saw one once.. and not for a small curve.. something really incredible.

  6. #51
    Join Date
    Mar 2010
    Posts
    2,004
    Well.. in fact I think it cannot be dragged to view from any angle like an animation.. but really 3D.. I'll try to find it.

  7. #52
    Join Date
    Sep 2011
    Location
    Cary, NC
    Posts
    105
    mehera

    Yes.. Look at EOS 2D/3D x-ray. There are a few centers that have this technology. It produces very nice, 3d x-rays, that can be viewed from many different angels. I haven't seen one in person but have seen presentations on them. A really really really neat thing. I also understand that the amount of radiation exposure is less than a normal x-ray (although I could be wrong about that). It's certainly no more exposure than a standard x-ray.

  8. #53
    Join Date
    Mar 2010
    Posts
    2,004
    Quote Originally Posted by Kevin_Mc View Post
    mehera

    Yes.. Look at EOS 2D/3D x-ray. There are a few centers that have this technology. It produces very nice, 3d x-rays, that can be viewed from many different angels. I haven't seen one in person but have seen presentations on them. A really really really neat thing. I also understand that the amount of radiation exposure is less than a normal x-ray (although I could be wrong about that). It's certainly no more exposure than a standard x-ray.
    Definitely better than a CT in all sense. It's strange for me that X-ray radiation is still considerable high, when something incomparable more sophisticated has the same amount of radiation..

  9. #54
    Join Date
    Mar 2010
    Posts
    2,004

    Returning to the subject.. sorry

    Scott, I think you are sure about your work and you think that you may finish it and it must to be finished in order to show it, otherwise you couldn't do anything with it. But it would demand you a great effort, so you are not doing it and trying to forget it, but is not something simple to do, mainly believing that may help many people.. surely it would be always a bad memory for you if you don't do the attemp.. but would be a really great effort..

    I lived a something similar situation many years ago.. I go directly to the conclusion: What you need is someone helping you to finish your work. Surely you may find someone .. you should to do the attemp.

  10. #55
    Join Date
    Aug 2011
    Posts
    35
    hello, well not to butt in but I can tell you for certian that 6 degrees of freedom means 3 translational and 3 rotational.

    the 3 translational would be your
    1)up/down or z-axis (so along a vertical line from feet to head)
    2)forward /back or y-axis (along a horizontal line parallel to the ground runing from belly button to spine)
    3)left/right or x-axis (along a horizonal line runing right to left)

    the other 3 degrees of freedom are the rotational components
    4)rotation around the up/down or z-axis (this would be the direction of twist)
    5)rotation around the forward/back or y-axis (this would be the rotation that creates the c or s curve)
    6)rotation around the left/right or x-axis (this would be lordosis/kyphosis)


    ok- so I don't know anything about spines but I know that 6 degrees of freedom are 3 translational and 3 rotational and it takes all 6 to describe the motion of an object. But if an object can't move in some ways then those directions can be omitted. Such as a car on a flat surface cannot move up or down nor can it rotate about eitherr horizonatal axis- so provided it is driving on a flat surface it would be described by 2 degrees of freedom. (I think- forward/back and rotation (turning)- its been awhile)

    I am only guessing but for a vertebrea I would think that it is in fact the translational movements that could be omitted (wouldn't that be like a slipped disk?) Maybe axial translation to describe the compression due to disk shrinkage from ageing.
    just my 2 cents. I like this forum- I am very interested in this. thank you
    Last edited by whatishappening; 09-21-2011 at 12:44 AM.

  11. #56
    Join Date
    Sep 2011
    Location
    Cary, NC
    Posts
    105
    Quote Originally Posted by whatishappening View Post
    the 3 translational would be your
    1)up/down or z-axis (so along a vertical line from feet to head)
    2)forward /back or y-axis (along a horizontal line parallel to the ground runing from belly button to spine)
    3)left/right or x-axis (along a horizonal line runing right to left)

    the other 3 degrees of freedom are the rotational components
    4)rotation around the up/down or z-axis (this would be the direction of twist)
    5)rotation around the forward/back or y-axis (this would be the rotation that creates the c or s curve)
    6)rotation around the left/right or x-axis (this would be lordosis/kyphosis)


    I am only guessing but for a vertebrea I would think that it is in fact the translational movements that could be omitted (wouldn't that be like a slipped disk?) Maybe axial translation to describe the compression due to disk shrinkage from ageing.
    just my 2 cents. I like this forum- I am very interested in this. thank you
    Exactly right.

    The translational movements could be/would be described relative to the mid-line. Indeed, this is a major component of how gravity calculations are done. The more complex models certainly include these 6degrees and use various modulus coefficients, e.g. disc 'spongy-ness', to determine how compression or other frictional forces might be generated.


    I'm trying to attach some pictures of what the EOS 2d/3d system is capable of. Or at least, the information that can be obtained can then be used in a variety of ways. I was correct that the amount of radiation is lower than a standard x-ray.

    Tamás Illés, Miklós Tunyogi-Csapó and Szabolcs Somoskeöy
    Breakthrough in three-dimensional scoliosis diagnosis: significance of horizontal plane view and vertebra vectors.
    European spine journal Ills yr:2011 vol:20 iss:1 pg:135 -143

    Let's see if the attachments work.



    scoliosis vectors.jpg

    scoliosis vertebral vectors.jpg
    Last edited by Kevin_Mc; 09-21-2011 at 12:42 PM.

  12. #57
    Join Date
    Sep 2011
    Location
    Cary, NC
    Posts
    105
    Quote Originally Posted by sjmcphee View Post

    By the way what is a vector? I consider it to be a line with angle and direction, but in my adobe illustrator they consider a vector to be a point on a line.
    A vector is generally a geometric object that has both magnitude/length and direction. It's usually represented by a line. In physics is can indicate force in 3d space.

    Wikipedia is usually a pretty good reference for basic concepts like that.



    Quote Originally Posted by sjmcphee View Post

    Now I'm not sure anyone is going to be able to grasp any of this, but I want you to know that it was by this method that I quantified the loading of the entire curve pattern at every intervertebral level.
    When you say you quantified the loading. What was quantified i.e. what number did you come up with and what is that number referencing?

  13. #58
    Join Date
    Mar 2010
    Posts
    2,004
    Quote Originally Posted by Kevin_Mc View Post
    I'm trying to attach some pictures of what the EOS 2d/3d system is capable of. Or at least, the information that can be obtained can then be used in a variety of ways. I was correct that the amount of radiation is lower than a standard x-ray.

    Kevin, it’s really great! That is the kind of improvements that we are needing. It should to be available for everyone!. Of course, the incomparable kind of image is the purpose (do you know the degrees of that curve?), but the lower radiation is the best news for me. It lead me to believe that using the same kind of technology, it should to be possible to obtain traditional 2D X-ray with incomparable lesser amount of radiation than the current ones. It’s something urgent!

  14. #59
    Join Date
    Sep 2011
    Location
    Cary, NC
    Posts
    105
    Quote Originally Posted by flerc View Post
    Kevin, it’s really great! That is the kind of improvements that we are needing. It should to be available for everyone!. Of course, the incomparable kind of image is the purpose (do you know the degrees of that curve?), but the lower radiation is the best news for me. It lead me to believe that using the same kind of technology, it should to be possible to obtain traditional 2D X-ray with incomparable lesser amount of radiation than the current ones. It’s something urgent!
    The curve was 49° pre-op and 8° post-op.

    I agree, I wish more hospitals would begin buying these machines.
    Attached Images Attached Images

  15. #60
    Join Date
    Aug 2011
    Posts
    35
    Quote Originally Posted by Kevin_Mc View Post
    The curve was 49° pre-op and 8° post-op.

    I agree, I wish more hospitals would begin buying these machines.


    scoliosis coronal EOS.jpg‎
    that is incredible- thank you very much for posting that.

Posting Permissions

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