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physiology of a nerve transfer
Posted: Wed May 13, 2009 1:18 pm
by racerboy
I’ve read a bunch of information nerve transfer surgery, both before and after I had it done back in March. The one piece that still puzzles me is when the fascicles are transferred over, is the expectation that they will grow along the same path as the injured nerve, to regenerate axons within the myelin sheath of the damaged nerve? For instance, my musculataneous nerve, though not avulsed, was stretched badly in the upper trunk of my brachial plexus. When the ulnar/median transfer was made, are they hoping that my attaching below the injured stretch, the existing axons can begin firing again? Because we are all told that nerves grow slowly (1 mm a day) I think the recovery is dependent on the ability of regenerating axons within the existing myelin sheath, as opposed to just hotwiring those below the injured part of the nerve.
I did not ask Dr. Wolfe this at my 2-week follow-up, but will certainly ask him at my 3-month visit in June.
Re: physiology of a nerve transfer
Posted: Wed May 13, 2009 5:52 pm
by Christopher
Both of your responses are correct. You are "hotwiring" an existing, yet injured nerve, below the point of injury with another healthy and uninjured nerve. This transfered nerve will have to regenerate from the point of attachment down to the target muscle(s). Within the existing injured nerve's myelin sheath, the transfered nerve's fascicles will grow, continuing onward to the target muscle.
I interviewed with Dr. Wolfe before choosing the Mayo Clinic, he is a very competent and good surgeon. If your nerve was not avulsed and stretched badly, did he not choose a nerve graft (replacing the damaged section only) instead of doing a nerve transfer because the roots were too damaged to access or work with? I know you said the "upper trunk" was damaged, and I'm assuming that it was just too close to the spine to access anything to graft to instead of transfering. Just curious.
Best of Luck,
Christopher
Re: physiology of a nerve transfer
Posted: Wed May 13, 2009 8:37 pm
by racerboy
Hi Christopher-
I believe that the stretch injury was too great for a graft to be used along, so he did 4 nerve transfers (ulnar/median to musculataneous; tricep to axillary (deltoid); and spinal accessory to suprascapular). The non-avulsion was confirmed from a pre-surgery scan I had where they do a spinal tap and inject you with dye, then partially invert you for an MRI of the cervical spine. I think the injury was very close to the root, but did not avulse the root from the spinal cord.
I also remeber Dr. Wolfe saying that when they had me open, if the damaged portion of the C5 C6 roots was relatively short, then I might be a good candidate for a graft, but when they got in there, I guess the damage was over a longer section of nerve than they typically like to graft.
Frank
Message was edited by: racerboy