I've been seeing a Neurologist now for 4 months for a damaged nerve (he said post traumatic neuroma) that is right on my cheekbone, next to my nose. I've had shots of Kennalog several times, and he says Xeomin could be the thing that stops the pain for good. My insurance won't pay for it because my diagnosis doesn't match it's approved uses, so I'm cosidering paying out of pocket. Also, he's treating constant sciatic pain with the kennalog, but relief only lasts a few days. wondering what to do.
Xeomin for a Damaged Nerve? Treatment for Sciatic Pain?
Doctor Answers 1
Unorthodox use of neurotoxin
This is a very interesting issue that you raise, and it really gets to the heart of medical innovation. The "first glance" surface answer to your question is that all of the botulinum type A neurotoxins, Xeomin, Botox, and Dysport, work the same way by disabling a protein called SNAP-25 which exists at the neuromuscular junction and is necessary for the transport of the neurotransmitter acetylcholine between nerve and muscle to initiate contraction of the muscle, and thus movement. This is how botulism causes paralysis. It then follows that one would expect the majority of the activity of these toxins to be directed toward the motor function of nerves and not the sensory component which causes pain, like the neuralgia experienced with a neuroma. Having said that, we should dig a little deeper and know first, that most nerves are mixed, that is that they are not purely motor or sensory, and second, there have been some unexplained phenomena related to pain syndromes and neurotoxin use, like the treatment of migraine headache with Botox. Why does that work? We don't really know. There are theories, but none have been proven. The convenient answer is that muscle contraction headaches may lead to migraines and these may be decreased by Botox, but nobody has PROVED this. There are also other theories implicating other neurotransmitters, like substance P, and there may well be some undiscovered function of botulinum that works in those cases. So, I would tell you that your neurologist may be onto something, but you would also have to recognize that he many not be as well. This is the "art of medicine, " and it's what makes our profession challenging, exciting, and interesting. I would not go so far as to say that he is recommending "experimental treatment," but it certainly is off-label use of the product, and it is empirical at best; that is, not based on proven scientific fact, rather based on our medical knowledge and judgment. It is somewhat speculative. In doing these things we must consider the risks against the benefits, and the one thing that I would encourage you to consider is that because of the proximity of those nerves to some important muscles of facial animation, you might wind up with some undesired weakness or paralysis of facial muscles with change in facial animation. If this is a worthwhile trade-off to get relief from chronic pain, it may be worth attempting. The good news is that with judicious dosing and treatment the effects are not life threatening and they will be temporary. Thus, if things don't work well, the effects will wear off, and you can simply decide to never do it again. A very interesting clinical puzzle, and I wish you and your neurologist luck in going forward.