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Thread: new bypass surgery

  1. #1
    Junior Member efsta's Avatar
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    new bypass surgery

    hey everyone, i found this link and wanted to find out a bit more info about it.

    i only heard about this bypass surgery 2nite whilst visiting my brother in rehab...

    http://www.theage.com.au/news/world/...234065071.html

    any opinions....info??

    thanks in advance
    effs
    "You gain strength, courage and confidence by every experience in which you really stop to look fear in the face. You are able to say to yourself, 'I have lived through this horror. I can take the next thing that comes along.' You must do the thing you think you cannot do." --Eleanor Roosevelt

  2. #2
    Junior Member efsta's Avatar
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    new bypass surgery

    hey everyone, i found this link and wanted to find out a bit more info about it.

    i only heard about this bypass surgery 2nite whilst visiting my brother in rehab...

    http://www.theage.com.au/news/world/...234065071.html

    any opinions....info??

    thanks in advance
    effs
    "You gain strength, courage and confidence by every experience in which you really stop to look fear in the face. You are able to say to yourself, 'I have lived through this horror. I can take the next thing that comes along.' You must do the thing you think you cannot do." --Eleanor Roosevelt

  3. #3
    Hi. I merged your doubled posts and moved them to the Cure Forum where potentially curative therapies of spinal cord injury are discussed.

    Martin at Columbia reported using peripheral nerve bridges to restore function to the spinal cord. The idea is actually quite a good one and one that has been previously shown to work. Because axons can grow in peripheral nerves and because they cannot grow in the spinal cord, one possibility is to grow axons from the spinal cord into the a peripheral nerve bridge from above the injury site to below the injury site. While this has been shown before, what Martin showed was that it can restore motor function in rats.

    Wise.

  4. #4
    Senior Member rdf's Avatar
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    Wise ?

    I asked a question similar to what this article lays out a couple of years ago, but it went unanswered. I don't know if that's because if was buried deep within a thread on another matter, or if Wise thought it was so naive that he didn't feel the need to answer.

    Forgetting the FDA for this propostion, please tell me if the ending supposition is viable. If any of the items listed are false, then the final supposition isn't possible.

    1. SCI persons with strong spasms below the injury level must have remaining axons still firing below injury level.

    2. We know from the brain stem all the way down the spinal cord which bundle of axons/neurons innerverate which muscles.

    3. It is possible to fuse or attach spinal (or other) nerves to other spinal cord nerves.

    4. Fresh cadaver spinal nerves/axons from a non-paralyzed person are still viable to be used in a live human. (or non-spinal cord nerves from either cadavers or nerves from other parts of our living body)

    5. We can take a fresh cadaver bundle of spinal axons and graft it to a paralyzed person's spinal cord, using micro-surgery. We can go over the scar tissue, or slice into it to lay the new axons.

    6. During the surgery, all of the latest approaches to prevent SCI in acutes will be used as the cadaver nerves are grafted to axons above the injury leve, as well as below the injury level, minimizing potential new damage.

    7. We're able to identify the axons remaining below the injury that are still alive and firing, causing spasms, so we know where to attach the below level axons.

    8. We can put an artificial protective sheath around the cadaver nerves before transplantation into the SCId person.

    If all of the above are true, then why can't something like this work? Is it being pursued by researchers other than the one mentioned in this thread's article? It would seem coupled with the plasticity of the spinal cord, that such a clinical trial should have started years ago, if all of the above items are true. If they're not true, please tell me if they're close to being true, or are not at all possible.

    Do we have the micro-surgical ability to do this at this time? Would the FDA not allow something like this for any reason you know of?

    Finally, are there researchers trying to grow axons in the lab, meaning in some type of solution in a petri dish? Or is all research of regenerating spinal nerves done only on laboratory animals?

    Thanks for any enlightenment. Please answer even if you feel the supposition is naive.
    Last edited by rdf; 04-10-2008 at 02:40 PM.
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  5. #5
    Senior Member rdf's Avatar
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    Excuse my interchangable use of axon and nerve. Where I say axon, I mean within a nerve of a fresh cadaver. Where I say bundle, I mean bundle of nerves containing non-injured axons of a cadaver.
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  6. #6
    rdf, I am having serious problems understanding your question and I don't think that it is due to the words that you are using. You are assuming certain things about the spinal cord and its connections that don't make sense to me. Let me start with a few definitions to make sure that we are on the same page conceptually and we are talking about the same things.

    • Axons are parts of neurons. If they are disconnected from the neurons, the axons die.
    • There are neurons in the spinal cord. Neurons in the spinal cord below the injury site receive input from sensory neurons that are located outside the spinal cord in the dorsal root ganglia. Motoneurons send axons out the spinal cord to the muscles. Activation of sensory input into the spinal cord below the injury site will cause reflex activity.
    • After injury, the neurons above and below the injury site becomes hyperexcitable. Hyperexcitability of the neurons below the injury site result in spasticity and spasms. Spasticity is increased reflexes. Spasms are organized movements that result from small input or even spontaneously. Clonus is when reflexes activate repeatedly.
    • The axons in a removed segment of peripheral nerve die because they have been separated from their respective cell bodies. So, what you have is just the scaffolding of the peripheral nerve. We know that this scaffolding will support axonal growth and therefore such peripheral nerve segments have been used to bridge gaps in the spinal cord (Henreich Cheng and Lars Olson). Others have used tubes of a material called matrigel as a substitute for peripheral nerves. Note that cutting a segment of the peripheral will result in the inability of that nerve to regenerate and therefore loss of function of that peripheral nerve.
    • It is possible to use a peripheral nerve outside of the spinal cord to allow axons to grow from above the injury site to the lower spinal cord. In the past, several groups have shown that axons of the spinal cord will readily grow into a peripheral nerve that has one end inserted into the cord above the injury site and the other end below the injury site. The difficulty was always getting the axons to grow back into the spinal cord from the nerve. However, Martin was able to get the axons to grow in and produce some functional improvements.

    Wise.

  7. #7
    Senior Member rdf's Avatar
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    Quote Originally Posted by Wise Young
    rdf, I am having serious problems understanding your question and I don't think that it is due to the words that you are using. You are assuming certain things about the spinal cord and its connections that don't make sense to me. Let me start with a few definitions to make sure that we are on the same page conceptually and we are talking about the same things.

    • Axons are parts of neurons. If they are disconnected from the neurons, the axons die.
    • There are neurons in the spinal cord. Neurons in the spinal cord below the injury site receive input from sensory neurons that are located outside the spinal cord in the dorsal root ganglia. Motoneurons send axons out the spinal cord to the muscles. Activation of sensory input into the spinal cord below the injury site will cause reflex activity.
    • After injury, the neurons above and below the injury site becomes hyperexcitable. Hyperexcitability of the neurons below the injury site result in spasticity and spasms. Spasticity is increased reflexes. Spasms are organized movements that result from small input or even spontaneously. Clonus is when reflexes activate repeatedly.
    • The axons in a removed segment of peripheral nerve die because they have been separated from their respective cell bodies. So, what you have is just the scaffolding of the peripheral nerve. We know that this scaffolding will support axonal growth and therefore such peripheral nerve segments have been used to bridge gaps in the spinal cord (Henreich Cheng and Lars Olson). Others have used tubes of a material called matrigel as a substitute for peripheral nerves. Note that cutting a segment of the peripheral will result in the inability of that nerve to regenerate and therefore loss of function of that peripheral nerve.
    • It is possible to use a peripheral nerve outside of the spinal cord to allow axons to grow from above the injury site to the lower spinal cord. In the past, several groups have shown that axons of the spinal cord will readily grow into a peripheral nerve that has one end inserted into the cord above the injury site and the other end below the injury site. The difficulty was always getting the axons to grow back into the spinal cord from the nerve. However, Martin was able to get the axons to grow in and produce some functional improvements.

    Wise.
    Thanks for taking the time to answer, Wise. Give me one more shot at trying to get my question right in my head, and thus make it more clear.

    According to what you've written, the referenced rat was able to move its hind limbs utilizing a peripheral nerve scaffold because the new axons grew all the way over the bridge and back into the spinal cord, then to the Lower Motor Neurons, in the process creating new spinal nerves as they exit the spinal column, thus innervating the rat’s hind limbs. Let’s keep it that simple (if what I've just written is even correct), and not go into ventral horns, gray matter, white matter, motor neuron dendrites, sensory neuron dendrites, etc. So I’ll understand and not have to bug you again on this matter.

    1. Did this researcher only use a peripheral nerve just long enough to bridge over the injury site, and from there, just below the injury site, the neurons and their axons grew on their own in length and back into the spinal cord, and then found their own way to the lower motor neurons that innervated the hind limbs of the rat?

    If this works as I've laid out, why can’t many peripheral nerves be spliced together to the length needed so that not only would it bypass the injury site, but be long enough to lead to near where the lower motor neurons enter the spinal cord, and have the peripheral nerve enter the cord at that point…then the peripheral’s neuronal axons should connect to other motor neurons much easier and much more quickly.

    2. People have organ’s harvested all the time, and I’m sure they’re kept technically alive while this harvesting takes place. Forgive my use of the term cadaver earlier.

    My question concerns Thoracic level injury. Can’t the 12 pairs of spinal nerves in the Thoracic level be harvested in whole from a still living organ donor and grafted above the injury level, as this researcher did with the rat, and and then reenter the spinal cord at the different levels where the lower motor neurons innervate our muscles.
    Don’t you think there’s a chance that the actual evolutionary created spinal nerve pathway for humans created over millions of years would be the best means available at accomplishing what Martin did in this article, if we replace his rat with a human being? Would these 12 Thoracic spinal nerves stay alive for the short time it took to implant them into the SCI patient, or is my belief that such a thing as harvesting spinal nerves from a living donor pure fantasy?

    Again, I’m confusing, as I have found many different meanings of the term “spinal nerves” when in relation to the spinal cord. Maybe the 12 Thoracic “spinal nerves” means simply neurons and their axons and dendrites, etc., that are connected only through synaptic firing, and isn’t something that is one unit, something whole, and not at all similar to a long piece of thread, or hair.

    To be blunt, are the 31 pairs of spinal nerves only neurons and their cell bodies, dendrites and axons, and are called spinal nerves only because they're made up of neurons and the firing of synapses in a consistent manner, but are free floating within the confines of the spinal cord - or are they actual fibrous material pathways in which the neurons exist in stationary form, and pass along synapses, much like I presume a peripheral nerve is in its organic makeup?

    If they’re the latter, then is there any possibility as to the viability of my two questions.

    Thanks again.
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