#883 Do you have to a cut a ligament to remove a painful neuroma? - DOC

#883 Do you have to a cut a ligament to remove a painful neuroma?

Do you have to cut a ligament in the foot to remove a painful neuroma? That is what we’re talking about today on the Doc On The Run Podcast.



I had a call from a patient who wanted to know about surgery for excision of a neuroma but believe it or not this patient I did surgery on more than 10 years ago, so she trusts me because I did a good job. But now she lives far away, and she is looking into having this thing treated and she said she went into the doctor and the doctor said, “Well, we can just take the nerve out. It is not a big deal. We do this all the time.”

Well, she has had surgery so she knows you should really think hard about this before having surgery even if I am doing it. It does not matter who is doing the surgery, things can always go wrong. So, you want to get the full information first and she said that it was said in passing that you have to cut a ligament to take it out. She wanted to know if that was true and what that really means.

So, here is what that really means. We were talking about neuroma in the foot and most of the time it is a Morton’s neuroma and a Morton’s neuroma is in a very specific location in the foot. If you want to make comments about my terrible foot drawings, go right ahead. I am just trying to make a point here but if you want to make fun of me go ahead. I am getting thicker skin by the minute doing all these YouTube videos.

Here is how it works. These are the metatarsal bones, in between the metatarsal bones you have some nerves that go out to the toes and in this space is where the Morton’s neuroma happens. So, Morton’s neuroma is typically the one that goes and divides to go out to half of your third toe and half of your fourth toe. So, it is in what we call the third inter metatarsal space meaning 1234, it is in the third space. And so, you get a lump basically in the nerve right there, between the metatarsals.

When we do the surgery, well most of the time, this is the bottom of the foot, this is the toe, you have the metatarsal here, you have the proximal phalanx bone, the intermediate phalanx and the distal phalanx bone and you have the nerve is underneath here, like this going up into the toes. Now, we do not want you to have a big old painful scar on the bottom of the foot. So, we don’t typically make incision on the bottom of the foot. If we did, you could do that, make an incision right on the bottom of the foot, neuroma would pop out and you would remove it without cutting any ligaments. However, since most of us are paranoid and worried about that painful scar getting on the bottom of the foot, we make the incision on the top of your foot. But that thing in cross section is what we call the inter metatarsal ligament and it basically goes across here like that. And so, you have to cut that.

Unless you cut that, you cannot get the neuroma out because we want to take out a section nerve that basically looks like a Y that is about like that. So, once we remove it, we actually do cut through this ligament, we cut it so it is in two pieces and then we take the nerve out and when we pull the nerve out of your foot, it is got a big lump in it, that is the neuroma and that is what it looks like but you cannot get it out without cutting the inner metatarsal ligament right there.

Is it a huge problem? Not for most people. But if you already have a little instability on the foot, it is reasonable to believe that it will create more instability. Why does it matter there? Well, part of the reason it matters there is that you have the cuboid bone here, lining up with these metatarsals, and you have the cuneiform bones that each line up with each of those metatarsals and they line up with the navicular bone, the navicular bone lines up with the talus and underneath the talus is the heel bone.

So, the heel bone is down here, talus is up here and if the way these line up, the outer two metatarsals, the fourth and fifth actually kind of move as a unit with respect to the other three, the first, second, and third metatarsals and they each line up with different bones. Those two bones, the talus and calcaneus is where your supination and pronation happens. So, a motion in your rear foot translates into sort of independent suspension at the front of your foot and that ligament provide some stability between those two pieces.

Maybe it won’t be a problem but if you are a runner and you are concerned about this, it is valid to actually ask the doctor, “Are you concerned at all that I am going to have any kind of instability that can actually bother me when I am doing sports, whether it is running or other athletic activity that could be a problem?” Because it could potentially make some instability that you might notice that others would not.

Remember, as a runner, not only are you more physically fit, you are also more physically aware. I think most runners have a good sense of their bodies, they feel things, they notice things that are good and bad in a way that as a little more sort of fine tuned than the average patient. And so, you might notice that instability and maybe bother you maybe it would not but it is a thing that does happen when we take out the neuroma, yes we cut through the ligament.

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