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Thread: Cord Tethering/Compression

  1. #1

    Cord Tethering/Compression

    I notice it seems to be standard protocol to decompress and or untether the spinal cord when performing spinal surgery on chronic SCI patients. How common is compression and/or tethering in chronic SCI?

    Due to some neurological changes, I've had a number of diagnostic tests performed recently (MRI, CT, Myelogram). Would cord tethering and/or compression be obvious on these tests?

  2. #2

    Quadfather

    Tethering and adhesions is very hard to diagnose on MRI or any of the imaging modalities. This is because adhesions are generally very thin and do not show up on standard images (CT or MRI). So, in general, two criteria are used to rule out adhesions. First, if there is cerebrospinal fluid completely surrounding the spinal cord, i.e. the spinal cord is not contacting the dura, this would tend to argue against adhesions. Second, the presence of tethering sometimes can be seen at the roots, in the form of a thickening of the membranes surrounding the roots.

    If the spinal cord is touching the dura or there appears to be thickening of the membranes surround some of the roots, it is possible that adhesions and tethering are present. On occasions, both of these may be present but the surgeon finds little or no adhesions when they expose the spinal cord surgically. If this is combined with neurological symptoms of pain and neurological loss, this should be sufficient to justify surgical exploration.

    The problem with surgical exploration is of course the occurrence of additional adhesions and tethering that may develop again. There are many approaches to this problem and every surgeon has his or her own favorite approach. This problem has not been seriously explored in animal studies before and we are currently doing so in the laboratory, to test the various approaches that work best in preventing adhesions and scarring about spinal cord injury and surgical exposure of the spinal cord.

    In recent years, several places have been experimenting with new imaging approaches that tries to see the movement of the spinal cord. In other words, while in the MRI scanner, they move the position of the neck and see how the spinal cord moves. There have been several reports that report that this approach can detect tethering and adhesions.

    Wise.

  3. #3

    Follow-Up

    I do have a follow up question about your response; however, I would first like to thank you Dr. Young. Once again you have addressed a question that requires a complex and lengthy answer and done it in a manner that is detailed yet easy to understand. You are an invaluable asset to those of us with SCI because we would otherwise be unable to obtain such information, even elsewhere on the Internet. Your time, insight, patience, knowledge and energy are greatly appreciated.

    If one's cord were tethered wouldn't symptoms related to tethering occur not long after the initial injury (i.e. a year or less). Could neurological loss 15 years post, with no other previous similar symptoms be due to tethering? If so, why would tethering begin to cause problems so long after injury?

    Finally, where are the places you mentioned that are doing imaging to see spinal cord movement?

  4. #4
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    Quadfather- questions about tethering

    This message is in response to Quadfather's questions.

    Q: How common is compression and/or tethering in chronic SCI?
    R: Tethering is very common but it is probably not always symptomatic. That is, there are patients who have tethered spinal cords in other settings, e.g. a congenital problem, who may never display symptoms.
    Q: Compression? In general, the fullest potential to experience neurological recovery is considered to exist when the spinal cord or nerve roots are free of compression. In recent years definitive decompressive surgery following SCI has become the standard of care in many institutions. If surgery is performed successfully, new compression does not usually result unless there is a progressive deformity such as kyphosis. Some patients with chronic SCI have never been adequately "decompressed".
    Q: Would cord tethering and/or compression be obvious on these tests (CT/MRI)?
    R: I agree with Dr. Young's comments and usually I can diagnose tethering form either MRI or CT-myelogram, but not from CT alone. The quality of the MRI is very important and in order to diagnose tethering the MRI must be of high quality. Cine-MRI studies are often used in this setting and their interpretation is still in evolution but they especially meaningful in view of current belief that the lack of adequate CSF flow around the spinal cord can predispose to problems such as syrinx formation, that may co-exist with tethering. These studies are available at most major spinal cord surgical centers in North America but each institution may use slightly different protocols and interpretation.
    Q: If one's cord were tethered wouldn't symptoms related to tethering occur not long after the initial injury (i.e. a year or less).
    R: No, tethering is believed to be a form of chronic injury and can definitely be progressive over several years.
    Q: Could neurological loss 15 years post, with no other previous similar symptoms be due to tethering?
    R: Yes, it is one possible cause among many.
    Q: If so, why would tethering begin to cause problems so long after injury?
    R: Tethering can disturb CSF flow and lead to progressive pressure/flow related changes in the spinal cord. It can also probably be associated with repetitive motion-related injuries. Normally the spinal cord and nerve roots undergo considerable movement as the spine flexes, extends and twists. Tethering can restrict this motion and lead to stresses in the spinal tissue that may lead to cumulative injury. Sometimes cumulative injury must reach a threshold level to become obvious as a change in function.

    JD Guest

    ryley1

  5. #5

    Thank You Doctor Guest!

    I cannot overstate my appreciation for your participation in this forum. As I previously replied to Dr. Young's post, your generosity is invaluable to us and allows us to better understand the progression and potential risks with chronic SCI.

    As a follow up I have 2 unrelated questions:

    1. Your reply mentioned that tethering is one of many possible causes of neurological loss. Is there some way I could get your professional opinion of my films? I am, of course, willing to follow any protocols you stipulate (to ensure you are compensated by my health insurance provider).

    2. As a member of the renowned Miami Project, do you share Dr. Young's optimism for the prospect of meaningful treatments for SCI (acute and chronic) in the near future (less than 10 years)?

    Again, thank you Dr. Guest. Your participation herein is appreciated and encouraged!

  6. #6
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    Response to Quadfather

    Thankyou for your expressed appreciation.
    1. re your first question about reviewing your films. It is true that MRI and other radiologic studies are able to provide considerable insights into patient's problems and the process of film review is a useful one. It is not my intention to use the forum to solicit business. Let me check with Dr. Young to see if there is a policy about making consultation agreements and I will let you know. I appreciate your confidence.

    2. Re: my personal thoughts about the future of SCI research. Yes, I am hopeful. I think that the problem of nervous system restoration is probably the most complex that has been approached by human beings. I date my inititiation into the research community from the beginning of my PhD in 1993. Since that time several true paradigms have been elucidated such as the presence of stem/progenitor cells in the CNS and the recognition that inhibition of axonal "growth" is built into the adult CNS. I believe that "short distance" regeneration is an achievable goal in some patients within the 10 year horizon. That type of regeneration over many mms, or cms, could result in some recovery particularly in the cervical cord and conus medullaris. Also, many other lines of research, that focus on other issues besides regeneration are progressing very well, such as treadmill training in incomplete SCI.
    I think that there will be some false starts and unexpected, possibly adverse responses to some of the therapies that will be part of forward progress but I am definitely optimistic.

    JD Guest

    Originally posted by quadfather:

    I cannot overstate my appreciation for your participation in this forum. As I previously replied to Dr. Young's post, your generosity is invaluable to us and allows us to better understand the progression and potential risks with chronic SCI.

    As a follow up I have 2 unrelated questions:

    1. Your reply mentioned that tethering is one of many possible causes of neurological loss. Is there some way I could get your professional opinion of my films? I am, of course, willing to follow any protocols you stipulate (to ensure you are compensated by my health insurance provider).

    2. As a member of the renowned Miami Project, do you share Dr. Young's optimism for the prospect of meaningful treatments for SCI (acute and chronic) in the near future (less than 10 years)?

    Again, thank you Dr. Guest. Your participation herein is appreciated and encouraged!
    ryley1

  7. #7
    Senior Member alan's Avatar
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    Bumping this back to life, with a question:

    If one has untethering surgery, would it make sense to give methylprednisolone before or during the surgery, to possibly prevent a recurrence of tethering?

    Alan

    There's a fungus among us, and I'm not lichen it!

    Nerve Center Telnet BBS - tncbbs.no-ip.com

  8. #8
    In most spine surgeries, some type of antiinflamatory is usually given. It may be Dexamethasone.
    It is to prevent swelling and possibly scar tissue formation.

    CWO

  9. #9
    Senior Member alan's Avatar
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    Is there a certain type of MRI scan that better shows tethering, if it is there?

    Alan

    There's a fungus among us, and I'm not lichen it!

    Nerve Center Telnet BBS - tncbbs.no-ip.com

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