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FAI November 2024 Podcast: Outcomes of Charcot-Marie-Tooth Disease Cavovarus Surgical Reconstruction
00:31:13
Charcot-Marie-Tooth (CMT) disease is a progressive inherited neurologic disorder causing muscle weakness and lower extremity deformity. The goal of foot and ankle surgical treatment is to create a stable, plantigrade foot, with the potential...
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- [00:00]
A
Hi, this is Charlie Saltzman, Editor in Chief of Foot and Ankle International. I'm excited to announce that Dr. Mark Easley, a great friend and extraordinary foot and ankle surgeon, will start today as the podcast Editor for Foot and Ankle International. Mark has served the American Orthopedic Foot and Ankle Society in virtually every capacity possible, including the mission critical roles of President and as Program Chair, and he now serves our global community as President of the International Federation of Foot and ankle societies. Dr. Easley's day job is as Surgeon in Chief of the highly productive Foot and Ankle Service at Duke University. And in my mind, he's the ideal person to be the Foot and Ankle International Inaugural Podcast Editor. Undoubtedly, he will raise the level of discourse and quality of our podcast. I welcome Mark to our program and look forward to his leadership.
- [01:09]
B
This is Mark easley. For the FAI podcast series, I am discussing with Dr. Glenn Pfeffer and Dr. Edward Haupt the outcomes of Charcot Marie Tooth Disease. Caylo Vera Surgical Reconstruction, the lead article for this particular Foot and Ankle edition. Let me introduce Dr. Pfeffer. Glenn is the senior author. This is his eighth study on Charcot Marie Tooth disease, published in Foot and Ankle International. He is the past President of the American Orthopedic Foot and Ankle Society and is a professor at the Department of Orthopedics at Cedar Sinai Medical center in Los Angeles. He's also currently on the Medical Advisory board of the Charcot Marie Tooth association and the Hereditary Neuropathy Foundation. Edward Halt or Eddie Haupt is the first author. He's a Senior Associate Consultant with the Department of Orthopedic Surgery at the Mayo Clinic, Jacksonville in Florida. Eddie was an All American football player and earned two national championship titles with the University of Florida Gators prior to completing his medical and orthopedic residency training at his alma mater. Before starting his practice at the Mayo Clinic, Dr. Haupt spent a year of fellowship with Drs. Thorderson, Charlton and Pfeffer at Cedars Sinai Hospital. So we'll get into some questions now and I'll start it off by asking Eddie as being the lead author, would you please give the listeners a general overview of Charcot Marie tooth disease and a brief summary of your paper and its major findings.
- [02:55]
C
Charcot Marie Tooth or CMT is a family of diseases. Actually, these are all hereditary motor and sensory neuropathies caused by multiple different genes with variations in genetic penetrance between genotypes. So broadly, CMT results in length dependent impairments of the motor and the sensory nerves and most patients with CMT develop an archetypal deformity and a pattern of weakness. So most commonly the CMT foot exhibits intrinsic muscle wasting and contracture and imbalances develop as certain muscles weaken faster than others which disrupts this normal agonist and antagonist relationship. This leads to a characteristic cavivarous foot deformity, sometimes with claw toes and then gait non ankle instability results often due to foot drop and evertor paralysis. So couple this with these events occurring during growth and some pretty significant deformities can develop which obviously cause significant disability for CMT patients. Bracing has historically been the mainstay for stabilization of a foot with CMT. And around the country medical providers of various specialties such as neurology or primary care or even orthopedic surgeons don't believe surgical treatment is necessary over the braces. Especially considering CMT is known to be progressive due to its genetic inheritance. So what is the role for surgical treatment that's to be able to walk and enjoy life with a stable brace free foot? The surgical treatment can be employed to correct the deformity with soft tissue balancing and bony work to make the foot planigrate and address these imbalances with tendon transfers. And so what this study did is it looked at a series of CMT patients, the largest series of CMT patients to date receiving surgical treatment for exactly this the archetypal deformity and weakness pattern. This study examined the effects of surgical treatment using primarily patient reported outcome measures, comparing the scores before and after surgery was completed and that including all planned surgical treatments. So even patients with bilateral reconstructions. And what we found is significant improvements in physical function and reduction in pain result from surgical treatment in patients with CMT with follow up with a minimum of one year. In this series we looked at subgroup analyses as well trying to describe more severe patterns of illness. And what we found is that even these more severely affected patients also experienced benefit from surgical treatment through their initial though their initial scores may be blunted or reduced compared to the group as a whole.
- [05:29]
B
Thank you Eddie. That's, that's important that we have a good overview. Now I'm going to turn attention to Glenn. I assume Glenn will probably occupy some time, but what many of you may not know is that Glenn is an accomplished magician and you can catch his act at the the Magic Castle in la. So it's something you definitely want to put on your calendars. He's also skilled in the art of banzai. So two things that many of us don't really understand and have much skill understanding how these actually are carried out or pulled off even more so, I think much of us struggle with the surgical management of Charcot Marie tooth disease foot deformity. So Glenn, your surgical indications and approach used for the patients in this particular study is based on your previously published algorithm and conclusions from consensus group collaboration. And you made that clear in the article. Would you though briefly share with us with the listeners your surgical strategies for cmt? Would you also clarify when you may use an arthrodesis in combination with or in lieu of tendon transfers?
- [06:47]
D
You know, I do about 70 CMT cases a year at Cedars and there are definitely some key strategies and controversies that I think are worth going over. It's hard to be brief, but I will try to be quick. There are three major objectives as we know for a CMT surgery. The first is to get a plant degraded well balanced foot. The second is to create a stable hind foot. And the third is to eliminate the need for braces or at least to minimize their use. And here's how I try to go about that. And over the past 10 years I've really standardized my approach to this problem. My first was in 1989 and I've learned a lot since then. Before surgery begins, I stress the ankle under anesthesia using fluoroscopy. I usually don't find significant laxity, but if there is, it's typically interestingly isolated to the calcaneofibular ligament which I reef up later in the case and fix it with an internal brace. Before I start operating, I always draw out the potential incisions. With eight average procedures, I no one wants to get caught with compromised skin bridges. Next I check out the Achilles or the gastroc. I find the Achilles is often contracted. That shouldn't be surprising in a patient who has weak dorsiflexion and a drop foot. But I know that many patients disagree with. Excuse me, many surgeons disagree with me. The contracture has to be corrected as it creates a varus pull on the hind foot. Because of the largely medial insertion of the Achilles, I typically do a hoax triple cut right in the beginning of the case as the ankle comes up. As we know, the long toe flexors will start to tighten and percutaneous tenotomies are often needed at the base of the toes. I use an 18 gauge needle. Now the most important surgical principle is to release all the soft tissue contractures before any osteotomies are done. Is it's absolutely impossible to know what to do with the bones until the soft tissues are released. Joints that seem fixed and irreducible preoperatively usually are not in the foot. Typically, my releases include the pt, posterior tibial, the tale and navicular capsule, spring ligament, peroneus longus and the plantar fascia through a separate incision in the midfoot. The first incision I make is medially. Probably most of us do that over the course of the posterior tibial tendon. I always dissect the tendon far out onto its insertion insertion on the medial cadioform, just where the tibialis anterior inserts. For me, this is one of the most important aspects of this case and not well understood, I think in the CMT surgical community. The PT muscle often has some contracture, which makes sense in a cavo varus foot, and it doesn't have full excursion, although it's worth transferring if it's strong. This technique that I'm talking about adds a centimeter and a half, 2 centimeters of length to the PT, which is absolutely critical. Without that extra length when doing a PT transfer for drop foot, it's impossible for me to seat the tendon properly into the lateral cuneiform, the central axis of the foot. I never place the tendon under maximal tightness. I leave some play, usually 3/4 tightness to both maximize the PT muscle function and not limit plantar flexion, which I've seen when I've over tightened the transfer. Now, once I release the pt, the talar navicular joint is next. It's very important to do a generous debridement of the capsule of this joint, usually with a division of the spring ligament. Not always, but usually I was not. And I no longer release the subtalar ligaments I used to. And that led to about eight or nine patients who had an overcorrection gapping medially at the subtalar joint. But after everything's released, the supination starts to magically unwind, just like a nice magic trick. Only in extremely rare cases will I do a TN or CC fusion to hold the correction. Although I've heard surgeons talk about the need to always do a CC fusion. Now, even after the TN is well aligned, varus deformity of the heel can persist. And this can be a challenge. I've often heard surgeons say I couldn't get the heel reduced. I examine the heel carefully. Is the varus deformity coronal from the back, axial from the top, or both? We found weight bearing cts to be invaluable for the evaluation of this deformity. An isolated shift may not be enough. A Dwyer osteatoma may be needed. Not uncommonly. I do both, but watch out for overcorrection. Doing both is very powerful. In order to mobilize the tuberosity, I often do a plantar fascia release just below it and a stylus stripping, you know, the intrinsic muscles off the tuberosity. Max Michal and our groups published a wonderful study with me on the abnormal morphology of the calcaneus. It's worth reading if you're going to do CMT surgery. Just a few more points after the calcane osteotomy I work on lateral stability. We all know that the peroneus longus is the go to transfer for most of us. I make this particular transfer very tight with a Pulver Taft weave. I think of the transfer as a soft tissue subtalar fusion. If the peroneus longus is weak, too weak to transfer, transfer the fhl. If the FHL is too weak to transfer, I typically fuse the subtelar joint to create hindfoot stability. Almost all of the patients that had subtilar fusions in our study were for stability, not arthritis. Typically, calcane osteotomy has to be done in conjunction with the fusion. The remainder of the case is pretty straightforward. To correct the forefoot valgus in adults, a closing wedge osteotomy is done by me at the base of the first metatarsal. I use a 3.5 cannulated screw and a 22 gauge wire. It's inexpensive, fast, and there's no potentially bulky plate that has to be removed down the line. Rarely a similar osteotomy is needed in the second. Very rarely. And if more than two metatarsals need correction, that's when I go to a cold osteotomy in the midfoot. In kids who can be quite challenging in their forefoot deformity when the first metatarsal fight is still open, I'd suggest an opening wedge osteotomy of the cuneiform. This has been popularized by Vince Mosqua. I fashioned the graft myself from a fresh frozen iliac crest, but there are certainly other holograft options. And finally, I've heard surgeons say over the years that the PT always has to be transferred or released. I don't really agree with that. If it's not a significant deforming force and I can balance it out with a strong transfer laterally into the brevis, I leave it alone or perhaps do a 1cm z lengthening. This is usually the case, though in young People, you know, people that are 25 or younger. To treat a foot drop in these cases where the PT is left alone, I'd suggest a Hibbs procedure. Several years ago, Max and I published an FAR on this procedure. The EHL and EDL are transferred into the medial and lateral cuneiforms and held with biotenadesis screws. Again, I shoot for 3/4 tightness. It's an in phase transfer. It works great, but the lesser toe flexors have to be released percutaneously to avoid future contractures. And with the Jones procedure, which we all know, the IP joint needs to be fused. I use one headless screw and that highlights the high points for me of CMT surgery.
- [14:34]
B
Glenn, that was absolutely extraordinary. Thank you for taking the time and letting us see behind the curtain. As a magician, it's rare that we get to see how the tricks are done, but that's helpful. And I did want to ask you one more thing about the manuscript itself. So, in the limitations, you note that as a single surgeon study, you may introduce selection and sampling bias. You acknowledge that a group of CMT patients possesses rather heterogeneous presentations. And I'm sure that the listeners are curious. In studying the patients like you just described, how do you control for bias?
- [15:14]
D
That's an interesting question. We all have biases, surgical biases, but I suppose mine have to do with patient selection. I don't think anyone with a crooked callused Cavovaris foot should live in a painful brace, although I see many neurologists that disagree and some surgeons. And I'm also willing to operate on a person who might theoretically do well in braces but doesn't want to use them. An 18 year old says, I don't want to be in braces the rest of my life. If I can help them, I'll operate on them. In terms of surgical biases, I don't like split tendon transfers at any age. I think a tendon works best when it does one thing. Which is also why, parenthetically, I don't really like the bridal procedure in these patients.
- [16:09]
B
It sounded like to me that it makes perfect sense to follow this protocol you've worked out, and it has some variances, but you mentioned the limitations, so I wanted to make sure that was brought to light and explained a bit. Eddie, let's turn back to you with your football career. I assume that Tim Tebow owes much of his success to you, and it seems to me that Glenn owes a lot of his success with this work to you as well. Maybe I'm stretching it a bit, but that's what I see. But just with that said, what do you consider the major strengths of this particular study and what do you see as the major clinical implications of this particular work, this particular paper?
- [16:58]
C
Well, thanks, Mark. Those are kind words. I think, like I mentioned before, as well as Glenn, doctors around the country, surgeons included, don't all agree that surgical treatment is useful for CMT patients. And so I think the major strength the study is that there's objective evidence using patient reported outcomes that surgical treatment is beneficial to improve physical function and reduce pain. And so we looked at the CMT patients here as a whole group, acknowledging that there is some variation that's well described in the paper. And so we focused really on patient reported outcomes here over radiographic or, you know, clinical outcome measures. So I think a strength of this, it really is using patient reported outcomes as the main looking glass for these patients. I really like that we try to describe these more severely affected patients. And as Dr. Pfeffer described, arthrodesis here, in contrast to many other publications, wasn't just limited to arthritic deformities, but also applied as an adjunct for treatment of muscle weakness. And so this severely affected group. Air quotes. Is a challenging group to treat. And so we found this group to be worse off than the main group of CMT patients, which obviously are worse off next to population norms. But we found that these more challenging patients also have an equivalent improvement in outcome measures. And so saying even somebody that may only have one functioning muscle to transfer also benefits from surgical treatment. I think that's. That can be news to many people. And so I think those are the main clinical implications of the study.
- [18:38]
D
Great.
- [18:39]
B
Thank you for sharing that, Glenn. I'll turn back to you. This is probably more of a personal question I have, but I've run into this. When I see patients with any neurogenic component to their disease process, my anesthesiologist has some hesitation when it comes to surgery. So you described the surgical techniques in great detail in your treatment algorithm and what you've learned over the years. But your study suggests that your CMT patients are routinely discharged home with a regional catheter for 3, 4 days to control their post operative pain. We do some of the same or there's some other methods of doing that in my institution for patients without neurologic conditions or baseline issues. So my anesthesia team is very hesitant to perform regional blocks in patients with baseline neurologic deficits for fear of exacerbating those Nerve deficits. Is this concern, Is this a concern that's really unwarranted?
- [19:43]
D
I've heard that concern from different medical centers around the country. But first I'd like to say I'm really honored that you think I'm like Tim Tebow, that we, he and I are very similar. Over the years, I've had patients who've had prolonged numbness. It's worrisome. Most of them resolve, but not all of them. Since 1989, though, I've done about a thousand CMT surgeries. So it's not something that stops me from doing it. There are multiple papers, though, in the anesthesia literature, Mark, that talk about the safety and efficacy of blocks in CMT patients. I was just looking at some the other day from the Canadian anesthesiology literature. But in our literature, two years ago, Tanya Ahn was the lead author in a foot and ankle paper that looked at 20 of our patients who had blocks and indwelling nerve catheters for three or four days postoperatively. And we found no significant problems. Limited number of patients over a limited number of times. But if we couldn't use the catheter and do this as an outpatient, I don't think it would be possible. Before the catheter, we had some intractable pain patients that were discharged as an outpatient. So I think it's unjustified. It's reasonable concern, but unjustified.
- [21:20]
B
Perfect. Thank you for letting me know. I'll talk to my anesthesia team. And my understanding is that you had an anesthesiologist that you worked with that now is maybe at my institution. So we'll have a common thread. I'll try to get to the bottom of it. Eddie, back to you. Your investigation is strong in patient reported outcomes, but you and Glenn both acknowledged in the paper that there is a lack of post operative clinical testing and radiographic data. Do you believe that comparing pre and post op clinical and radiographic data would change your outcomes? And do you think that comparing pre and post op gait analysis would be meaningful?
- [22:03]
C
Well, first off, regarding gait analysis, I actually think that's the holy grail that we're all chasing. The initial IRB approval for the study actually included gait analysis. That's really what we're going for, right? I mean, a stable, you know, air quotes, normal gait that doesn't require a brace, right? Yeah. But unfortunately, due to just geographical and logistical constraints, we weren't able to pull that off with this study in a standardized manner. But, boy, Would I like to see that done? And that's something that we as a group, or even we as a foot and ankle society need to pursue. So regarding measurement of a clinical data, I think what we're talking about here is like range of motion and motor strength, right? So we, we thought about this, we acknowledged that the measurements are going to be variable between examiners. And you know, the big problem here was that a lot of these patients travel from far away for surgical treatment at Cedars. And so this is something that's, you know, very difficult to do on the phone or over video. You know, not to mention that a big portion of the group also get treated with arthrodesis or tendon transfers as a portion of this, which has some expectation for range of motion limitations and weakness anyways, you know, a lot of these would be best resolved meaningfully with gait analysis anyways. And so we just didn't think that this could be accomplished in a standardized manner where it would change outcomes. And so almost certainly these are addressed by patient reported outcomes. Anyways, you know, lastly, the X rays, we only looked at preoperative radiographic measures. And that was because the standardization of what we could collect postoperatively on the patients just wasn't able to be done to the same degree as the patient reported outcomes. But published in Foot and ankle International from Dr. Song Jae Wong Song is actually the exactly what you're asking for. There's a comparison of pre versus post op weight bearing CT measurements, which is obviously a much more precise measurement tool. And that paper found that there's improvements in the, all these markers of the foot toward normal. And so while I would have loved if that was like perfectly overlapped with the patients in this study, just due to time constraints and the way in which the IRBs were done, they don't perfectly overlap. So in a perfect world we would have had that, but unfortunately just not the case here. And so, but again, do I think that would have changed the outcome of the study? Actually, no, I don't. And that's due to a lot of the variability of the patients. And at least I think we controlled that with like Dr. Pfeffer's, you know, what stereotypical surgical algorithm that he just described.
- [24:44]
D
Mark, if I could just add, Dr. Song has spent a year with us doing research projects and it's a beautiful study that he did. It's on 29 patients, as Eddie was saying, looking at pre and post op on the same foot weight bearing ct. And in that group of patients which overlapped with our Current Promise study, but not sufficiently to use the data. In our current study, it showed that we were able to nearly normalize many of the measurements of even severely deformed Kelovara's foot. I didn't believe it actually at first. We went over the data again and again, but I was happy to see it. It was real research and I was very pleased with those results.
- [25:29]
B
Well, certainly hats off to you for the patient reported outcomes. I was just curious, just something you mentioned in the write up and I felt it was good to hear it directly from you and it's good to know that your data is meaningful and it dovetails with some of the other work that's been done. So Glenn, while I've got you, CMT is a progressive neurologic disorder and I recognize that you have an ongoing follow up protocol for your CMT patients, even with the favorable results that you are now publishing in this manuscript. With surgical patients at a minimum, one year follow up and 21 month mean follow up. What has been your experience with longer term follow up in your patients? Is there still a benefit for these patients even when the outcomes can deteriorate due to progressive nature of hereditary sensory motor neuropathy?
- [26:24]
D
That's an excellent, excellent question. There's one seminal study in the literature coming out of Iowa by Reginald Cooper, who most of us have heard of, he showed 26 years follow up in CMT patients, all with continued good results. So I think that that's important information. I'll never get to that length of follow up I think in this study unless. Well, but we're continuing to add patients, probably about 70 a year and I look forward to see how they do. It's important. But I think one critical thing, if a patient comes in with this painful crooked cavovirus foot with calluses on the lateral border and we do surgery that creates a plant degrade foot and we know from Dr. Song's study that we are, even if the disease progresses, even if they have progressive weakness, we've created a plantigrade foot which will always be more braceable. So that's compelling to most of my patients and to me to keep doing this. No one mark in 2024 should live with a calloused, cavalierous, painful foot. We need to help these people.
- [27:48]
B
Great answer and very comprehensive. And thanks for sharing some of the previous literature too. I think that's important. So we're coming to the end of the podcast. This has been very informative and I like your candor too. And I've certainly learned a lot. I just want to finish with congratulating you on excellent work, both Glenn and Eddie. As we end this, is there anything else you'd like to share with the listeners? Maybe I'll give Eddie a chance first and then Glenn, you can finish up the session for us.
- [28:19]
C
Yeah, I think. Thank you to you and Charlie Saltson and Footnackle International for inviting us on to talk about it. It's a complex topic and a very important one for a group of patients out there with a unique problem. So I very happy to be here. I mean, this is the group that I want to be in with you and Dr. Pfeffer, Mark. So I appreciate everyone's time.
- [28:43]
D
Thank you, Mark. Thanks very much. I think we covered everything. You did a great job. Personally, I'm very gratified about what seems to be the increasing interest in CMT surgery across the world and specifically, particularly in our country. Let's keep it up.
- [29:09]
B
That's great. I'll ask you one last question. I am not a heavy social media user, but I do occasionally see your great work on social media. Would you just, in a very brief summary to conclude this, how effective is that? Do you find that? It's really. Do surgeons gravitate toward that? Do patients gravitate toward that? How does you sharing patient experiences influence the care of these patients, both from a surgeon referral standpoint or from patients reaching out to you?
- [29:48]
D
You know, I'm of the generation that's still a bit embarrassed about social media. And about eight years ago, a 16 year old girl from the Midwest said to me, Dr. Pfeffer, you have to reach out to more people. And I said, okay, how do I do that? And she said, start Instagram. I was very cool. I went, okay, that's a good idea. I went to the, to the office and I said to the resident, what's Instagram? We set up a site within a minute and the next day the guy cutting my hair told me how to put a video on. I didn't know it would happen, but it's wonderful for patients. It's just wonderful. They feel less alone. I had encouragement from the Charcot Marie Tooth association and the Hereditary Neuropathy Foundation. And in answer to your specific question, patients, people with cmt, they're direct messaging me all the time and I spend an hour, hour and a half every Sunday talking to them on the phone, whether they can come here to Cedars or not. And many of them do. So I think it's been a wonderful thing because otherwise they'd be living with their continued symptoms and pain.
- [31:00]
B
Well, I want to thank you both. It's been a great session, and again, congratulations to terrific work.