Section: CME Category: Foot Conditions

Tarsal Tunnel Syndrome

Harold Schoenhaus, DPM

Harold Schoenhaus, DPM discusses the etiology of Tarsal Tunnel Syndrome as well as diagnostic tests to help evaluate and treat it. Dr Schoenhaus also examines the different surgical treatment options to treat tarsal tunnel syndrome.

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Goals and Objectives
  1. Describe the etiology of tarsal tunnel syndrome
  2. Compare diagnostic tests for tarsal tunnel syndrome
  3. Examine different treatment options for tarsal tunnel syndrome
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    Release Date: 08/16/2018 Expiration Date: 12/31/2020

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  • Lecture Transcript
  • TAPE STARTS – [00:00]

    Male Speaker: Tarsal tunnel syndrome, certainly it’s a condition that you should be well aware off, no matter how many cases you see in a given year, of patients who have tarsal tunnel syndrome.

    It can be disabling, it can be very painful, and we’re going to take a look at a few important points that I have learned through the years in an attempt to alleviate the symptoms from this condition.

    Learning objectives, kind of simple what we’re trying to do. When we think of tarsal tunnel syndrome, we’re dealing with symptoms through the canal, that’s the third compartment of the laciniate ligament, within which lies the posterior tibial nerve, artery, and vein. And there are a number of things that take place within that canal that can affect the nerve artery complex, and primarily we deal with the nerve when we’re talking about tarsal tunnel syndrome.

    Some of the ideology is space occupying lesions, varicosities, ganglia, lipomas, accessory muscle, tenosynovitis of the adjacent flexors, bone spicules from fractures, foreign bodies, but what we often see is nerve entrapment, scarring, orthopedic compression, hyper pronation, posterior tibial tendon disease, trauma, and iatrogenic, and we recognize that that’s a small, confined area, and when that nerve becomes influenced or affected by surrounding tissues that are putting pressure on it, symptoms are going to arise.

    We probably don’t associate it as often as we should with a hyper pronated foot, recognizing that the compartment continues into the foot through this little canal.

    [02:00]

    The adductor canal going into the foot, often referred to as as the porta pedis or adductor component.

    So actually between the abductor loses in the calcaneus, and when you follow through the tarsal tunnel dissection, you go into these little canals and channels going into the foot, and it’s essential that you do open those areas to be sure there is no compression, and when you think about hyper pronation syndrome, you are going to increase tension on the abductor hallucis which is going to put pressure against the nerve.

    So there’s a good example of varicosities within the canal. That’s probably one of the easiest things to deal with because you just ligate, get rid of the varicosities. Recognizing when you do open this canal that the artery is sitting with the veins, the venae comitantes.

    So you have to very careful in your dissection because the artery is not that big. You don’t see this big pulsating vessel. Now, it’s questionable whether you should do these type of releases with a tourniquet or without.

    Certainly with a tourniquet you’re not going to be able to see the pulsatile effect of the posterior tibial artery or even palpate it, all right? So my preference is, I think I know the anatomy pretty well and my dissection is good.

    Where you run into problems is redo. When scarring takes place in that canal from previous tarsal tunnel syndrome, the vessel can even adhere to the roof of the canal, and inadvertently you cut the posterior tibial artery.

    Now as a reasoning, if you cut the posterior tibial artery, what’s the first thing you do? You go to the bathroom and change your underwear, because this is like, “Uh-oh, major problem.”

    [04:02]

    Vascular supply to a good portion of the foot plantar, recognize, however, in a rather healthy patient, you’ve got a perineal artery and you have the dorsalis pedis. So most trauma people will tell you, at worst, you sacrifice the posterior tibial artery. You’re not losing a foot because of that.

    Here’s an example of scarring with adhesions. This is a nightmare when you try to dissect through, and there are new devices would… evaluate nerve transmissions. So when you’re dissecting through scar, it helps you identify where the nerve might be. You certainly don’t want to cut or sacrifice the entire posterior tibial nerve. The distribution after it’s dividing into medial lateral plantar nerves is the entire plantar aspect of a foot, so we don’t want an insensate foot. So these are the nightmares that one deals with. These are usually secondary trauma or previous surgical procedures.

    Diagnostic testing, MRI can be helpful, provocative nerve conduction velocity testing, and I’ll tell you what I mean by that, CT, ultrasound. If a patient is developing tarsal tunnel syndrome, the sensation of burning or sharp pain radiating into the foot, or noticing contractures of tendon or the toes bending down occasionally through the day, these are patients who may have symptoms secondary to the hyperpronation syndrome.

    If you’re ordering an NCV, it may not come back abnormal. So when I order these, if I suspect it secondary to pronation, I do a provocative test.

    [06:00]

    That means I want that patient walking down and back a number of times, hyperpronating, irritate the nerve, and then have the test done. So that to me is provocative testing. They also do that, by the way, with carpal tunnel.

    Clinical symptoms, tingling, burning, intrinsic atrophy, clawing of digits, numbness, heel pain, bulging in the retinacula, recognize heel pain syndrome could come from the medial calcaneal branch, which often comes off the posterior tibial nerve in the canal. So when you go in and do your dissection, you’re going to be carefully looking where the medial calcaneal branch is.

    Some people like to use loops when they do these dissections to follow the more finite branches. It’s all about what you’re used to, what you’re accustomed to, and how comfortable you are.

    I think diabetes is one of the critical disease entities associate with these symptoms of tingling, burning, paresthesia, atrophy. And there had been numerous articles and surgeons who have recommended doing tarsal tunnel release in diabetics. Also common peroneal nerve releases -- deep peroneal nerve releases, alleviate pressure on the nerve.

    Anatomic considerations, the tibial nerve bifurcation, divides into the medial and lateral plantar nerve. And Sharifian showed that within talocalcaneal tunnel, 1.3 to 2.5 centimeters proximal to the division of the posterior tibial artery. Now those are nice things to read about, but every patient is kind of unique and different. So when I go ahead and do my tarsal tunnel releases, I make the incisions high and low.

    [08:05]

    This is not a time when small incisions are utilized. I like to come in to the canal proximally, before any disease entity such as scarring might be present. Un-root the laciniate ligament very carefully and then observe and find your neurovascular structures. The nerve usually lies deeper into the canal and it’s surrounded by fatty tissue. It’s amazing when you open a canal, you think you’re going to be seeing something pop out at you with a light -- flashing light that says, “I am the tibial nerve,” doesn’t happen. You often have to go fishing into the canal to find the nerve complex. And then carefully dissect down toward the porta pedis. So as you could see, distally, I’m following those nerve branches as they go distally.

    And we talked about the medial calcaneal branch and where it comes off. Now, I recognized once that nerve bifurcates or divides, it may go through two different tunnels going into the foot. And based upon the symptoms, if a patient has more lateral plantar nerve involvement or pain versus medial plantar, you can actually have two different parts of the foot that had been affected by compression or pressure on the nerve. So your dissection is going to be kind of predicated on the symptoms that you evaluated preoperatively.

    Non-operative treatment, steroids, non-steroidals. We often give injections into the canal to try to alleviate symptoms, carefully done.

    [10:00]

    Local anesthetic to determine if in fact by eliminating the impulse along the nerve, do the patient’s symptoms improve? Does that tingling or that burning or that sharp shooting pain subside? That to me is indicative of problems coming out of the canal. Recognizing that symptoms, the tibial nerve is coming from all the way up from the low back area. So we can’t put blinders on to say, “Where is the disorder or the disease?” But the nerve conduction study, an EMG study may be helpful in identifying if there’s abnormality more proximal.

    Orthotics, interestingly, stop the hyperpronation syndrome. Medications. I’ve used Lyrica pre-regularly. Diabetic seem to respond pretty nicely to Lyrica with neuropathy. This is a form of a type of neuropathy or neuralgia associated with it. So attempt to use medications to alleviate the symptom complex. So in diabetes, it’s obviously from the diabetes.

    So the surgical treatment is the one that all of you sitting here enjoy probably the most. Opening this area up. And here’s the dissection that I utilized and I mentioned it earlier. Be careful distally to release the abductor hallucis into muscular septum. That’s the trickiest part because it’s often buried a little deeper and your vascular supply and neural supply are going through some more canals. Now you can come distally to do that. As you see on this picture, you look distally, you see that red belly of the abductor.

    [12:01]

    So you can pick up the canal either distally or proximally and work your way from either direction freeing up the nerve and doing any resection that is necessary.

    You can easily see how I am following the nerve, I’ve put these little band retractors around the nerve to gently pull it up. You want to be very careful in the canal. Any instrumentation you’re going to use potentially can be traumatic to the nerve. It can also rupture an artery or a vein by your dissection, depending upon how much scarring or what the etiology is.

    So I use these things called peanuts, which are almost like little cotton-tip applicators to gently push tissue to the side as I’m doing this careful dissection. But I need to free up the nerve from proximal to distal, evaluating disease of the nerve if it’s present and freeing up the nerve along its entire pathway. And here we are just cutting that septum to free the nerve up completely.

    So now, you can see and visualize a beautiful bed in which the nerve is now going to sit. And you could see with the red banner retractors, those little ribbons, that’s the neurovascular bundle sitting in that one. And the yellow one behind that is where the nerve is, and then we just follow it down.

    Let me go back for a minute. You could see a little branch coming off that nerve, and that’s part of some of the medial calcaneal innervation. Now you want to do -- be careful that you don’t do too much damage because in your dissection you could inadvertently cut one of these little filaments, and the patient says, “That’s good, my pain subsided, but now I’m numb on the inside part of my heel or the bottom of my heel. Is that going to come back?”

    [14:12]

    It’s not coming back. But a little numbness, I find, is more acceptable to a patient than pain, especially if it’s only in a small area.

    So we have released the laciniate ligament, released the abductor, and the intermuscular septum, addressed the ideology. If there’s scarring, you got to remove it. Varicosities, we’re clamping them off. And now, what do we do? We’ve done this beautiful dissection. We lay out the structures, recognizing they were in a tight canal. And you’ve incised that canal, so what are you going to do?

    So over the canal -- put the canal back together, so everything is protected. You now have, again, a tight environment into which the neuromuscular -- neurovasculars structures are sitting. So I was never happy with a beautiful dissection, and then I sew everything up, and now I’m setting the environment for scarring again. So, there’s a certain percentage of patients through the years where I’ve had to go back in and do another release.

    So over the last number of years, we’ve started looking into nerve wraps. What can we do to protect that nerve after we’ve done this beautiful dissection? And to prevent scarring and adhesions?

    Well, there’s a number of companies who have come up with products such as collagen. Stryker has a NeuroMend, Integra has a NeuraWrap. And certainly, I take that nerve, which I have beautifully isolated. And here is a little -- it looks like a cocoon that you’re going to place around the nerve. But it’s still a foreign substance that I’m putting in, which I wasn’t totally comfortable with, but I’ve had some good success with that.

    [16:06]

    On the other hand, the introduction of amniotic membrane has become an incredible adjunct to my surgical procedures when there’s nerve involvement. Because now I can wrap the nerve with a material. It’s almost like cellophane. You wrap the nerve, and now we’re going to have this protective component coming from amniotic membrane, which certainly minimizes the tendency for scar formation and protect the nerve during this healing process.

    So there’s a number of companies, you probably have seen them out there in the exhibit hall, who have various types of amniotic membrane, and I’d like to try just about every one of those. Some have easier handling properties, some have far more difficult ones. I certainly don’t want to use a difficult material that immediately wrinkles in my hand, then it rolls up and I can’t even find it, or open it up again to act as a membrane. I don’t want that to take more time than my original surgery took.

    So you’re going to select the product that’s going to be most efficacious for you, whether it’s straight amnion or an amnion/chorion sandwich, which has amnion on both sides, it’s an easier structure to use. Some are frozen, some are just dry, and you will just wrap around it and moisten the environment, and you now have this beautiful envelope, which we rarely even suture over the nerve. It just wraps around, like putting saran wrap around a sandwich. And I’m not going to bore you with that, but you can see the entire process of the effect of amniotic membrane and how it cuts down on any inflammatory process and allows for a healing process to take place rather quickly.

    [18:04]

    Here’s one of those nerves. That’s a nerve stimulator that you’re seeing when you’re going back in to do more involved surgeries, or where there’s a fair amount of scarring that you want to identify the nerve, you can actually locate it, stimulate it, watch the muscles. The intrinsics contract because they are the ones being innervated by this nerve supply. So you’re carefully dissecting down through.

    Here’s an example of one of the thicker materials of an amniotic product where you’re actually wrapping the nerve. And then we close over it. Now, actually, even, like, using amniotic, either fluid or membrane, where the laciniate ligament might be loosely put back together, between that, and the -- now, the subcutaneous layer you use an amniotic membrane, and that prevents further scarring between the skin and the laciniate ligament itself.

    And there’s just a good example of wrapping that material around. And that’s what it looks like when you pretty much finish creating this protected environment. And there are times when I won’t even try to close the boarders of a laciniate ligament. I’ll just lay a membrane over that, and that will be the final portion. And that’s what that is right there.

    So I shared with you a concept of what tarsal tunnel syndrome is all about and a methodology of material that is available in our armamentarium to lessen the post-operative complication of scarring.

    I thank you for your time.

    Are we going to take a short break? Let’s take a short break of about 15 minutes, no more.

    [20:02]

    And then we’re coming right back in and Dr. Lee Rogers will be giving some excellent talks on bio skills and life skills. Thank you.

    TAPE ENDS [0:20:14]