Podcast Transcript: Free Flaps 101

[Dr. Gopi Shah]
Tell us about post-op. Do you, one, have a protocol or anything like that? Two, are we doing Q1 flap checks the first 24 hours still? Then Q2, is that still happening? Then what are some signs? Do you have an algorithm if somebody is concerned for whether it's venous congestion versus an arterial problem?

[Dr. Eli Gordin]
Yes, we've got a protocol. We just revised it actually. It's now 24 pages or 25 pages long.

[Dr. Gopi Shah]
We don't have to go through all 25 pages.

[Dr. Eli Gordin]
Good, because it takes an hour and a half. I did that yesterday.

[Dr. Eli Gordin]
We're trying to create a document that's both tells people what happens on each day, post-operative day, and things to look out for when preparing for a case and pre-op preparations and things like that. Then also filling in the rationale behind different things and all kinds of stuff like who might be appropriate to decannulate and how you decide if somebody is maybe ready to start PO intake or capping their trach or whatever. There's just a lot of background information in there too. It's not all just day-to-day do this at this point in time.

As far as flap checks, we do Q1 hours for almost 72 hours. We have them go to the ICU. We don't have an intermediate or a step-down unit, unfortunately. Q1 hour checks can't be done on the floor. They can do Q4 hour, I believe is the most frequent checks that they can do.

[Dr. Ashley Agan]
“They” being like, nursing, right? It's nursing doing the checks?

[Dr. Eli Gordin]
Correct. It's a nursing order. Yes, nurses can't because of the number of patients they have. They're restricted by the frequency of different orders that can be carried out on patients on the floor relative to the ICU. ICU can do Q1 hour nursing flap checks. That's what we do.

[Dr. Ashley Agan]
What does that entail, Eli? Is that just them Dopplering the stitch, or what are you asking?

[Dr. Gopi Shah]
They document the color, the warmth?

[Dr. Eli Gordin]
Everything. As long as it's visible, then flap check entails looking at the flap. Does the color look normal? It should just look like normal, healthy skin. Unfortunately, a lot of times the flap is more pale than the surrounding tissue, especially when it's coming from the leg and it's going to the face or the thigh. It's pretty pale relative to the face. It's always going to look pale relative to the surrounding tissue, but it's really more of a change than anything else. Whether it looks pale, extra pale, whether it starts looking purple, which might be a sign of congestion—

Edema, like I mentioned, is pretty normal and flaps, especially perforator-based flaps, they tend to get pretty edematous slowly over the course of the first three days. That's the peak I think is around day three. Then it starts slowly tapering off again, but a sudden change in flap edema or swelling that might signify hematoma under the flap or hematoma in the neck or wherever else.

The temperature is not the easiest thing to assess. A lot of time the flap does feel more cool relative to the surrounding skin, but you palpate it. You feel the temperature, you feel the general turgor or just how tight it feels. It again should feel pretty normal, but it does get swollen. Then the Doppler check. Usually, we have some degree of donor site extremity checks too. Just doing the same thing with the hand. If it's a forearm, just look at the hand, and especially thumb and forefinger, which are the distal most in the circulation.

If you're getting your circulation from your ulnar artery now and you have no radial artery, making sure that the cap refill and sensation and motor are all intact on the donor site, and there's no evidence of compartment syndrome developing. Then if there's any concern, then they call our resident team, and then the residents would assess. If they agree that there's something questionable on the flap check, then the next step is to scratch it or stick it with a needle, depending on your preference.

Usually I take a scalpel and just make a tiny little, paper cut depth thing, just through the epidermis and barely into the dermis. Not anything that needs to be sutured up, but just a little-- Literally, it looks like a paper cut. I just find that easier to ascertain whether or not there's blood return than if you stick it with a little needle, then you look at the blood, and if it's not bleeding, then obviously that's concerning for ischemia. If it's bleeding real dark red blood that comes out extremely quickly, then that's concerning for venous congestion because you have backflow of blood into the flap. Then there's everything in between, which is usually where it is. Then you're trying to figure out what you should do at that point.

[Dr. Ashley Agan]
Normal would be a little bit of bright red blood, if everything is that reassuring?

[Dr. Eli Gordin]
Yes. Sometimes it's pretty brisk. It can be hard sometimes. Going back to the paper cut analogy, if you cut your finger like that, oftentimes it'll bleed pretty briskly for a little bit until you hold pressure and it stops. Sometimes a normal flap will bleed quite briskly, but as long as it's bright red blood, then I'm not too concerned about that. Then it might be something to just monitor and go back for the resident to check themselves every hour or a little bit more frequently just to make sure it's not something that's progressing.

Because a lot of times the goal is to catch things as early as possible, but that also means that in these situations where you're not sure, then you're trying to rule out whether or not it's a progressive perfusion problem. If you're catching it early, venous outflow obstruction, meaning the flap is now bleeding more than it ought to be, then over time that's going to worsen and the flap's going to start getting purple, and it's going to start getting blue. Arterial thrombosis that follows that is extremely difficult to salvage at that point because that means the entire flap has become static and clotted off.

If they come back and they can just scratch with a needle the cut that we already made there, and illicit bleeding from the cut that we already put there, that way you don't have to be stabbing the flap over and over again with needles because that ends up causing bruising if the flap's not dead. Then that becomes more difficult to interpret because now you have a bruised flap that may have a perfusion problem. Yes, you're just looking for the speed of bleeding, but again, as long as it looks bright red, even if it's pretty slow, as long as it's present—

When it's starting to get ischemic you see this weird serous component to the blood, you might see a tiny little drop of blood, and then there's this serous fluid that also starts coming out and that's usually a bad sign.

[Dr. Ashley Agan]
Is imaging ever helpful if you're not sure? Does CT, or ultrasound, or I don't know, are there any objective studies that help you decide?

[Dr. Eli Gordin]
The problem is if there's really a problem you need to act on it more quickly. You can't really wait around for trying to get a CT. Theoretically, I would think a CT angio you could look at it at the pedicle, you could do it like a duplex ultrasound and look at the pedicle. i think there are times when we've tried that when we were like, "I really don't think this is a true problem, but I just want to be able to sleep better tonight."

The classic teaching is if you're in doubt, just go back to the OR and just open it up and check because worst case scenario, you had an unnecessary take back and you spent a couple hours mobilizing the OR, and then half an hour to actually look in the neck and assess the pedicle. The patient's had a little extra anesthesia but a lot of times they have a trach anyway, so it's pretty easy to induce anesthesia in them. If they don't, and it's a difficult airway, then that factors into your decision making too because it's all just risk-benefit analysis, but really if you have a doubt about the circulation of the flap then going back to the OR is the gold standard thing to do at that point.

[Dr. Gopi Shah]
In terms of let's say you caught it early, we're going to do more frequent checks, and we're going to try the scratch thing, what do you use temporizing measures? Are we still doing things like nitrous or leeches? How do whether to do those things versus we need to go back?

[Dr. Eli Gordin]
It can be difficult to figure that out sometimes. Again, going back is usually the first line. Sometimes you go back and it looks fine, and the macro circulation looks fine, the artery looks fine, the vein looks fine, but the flap looks weird, so then that's some local or microvascular issue. For that, there's not really an operative intervention that you can do. Usually, in this situation it's some partial flap issue. You might have a very large flap and a portion of it is unhappy for one reason or another. Then you might consider using nitro paste in that situation.

Theoretically, you could use hyperbaric oxygen, which may help for small amounts of ischemic tissue although that's pretty difficult to do on inpatients who are ICU, post-op day one. Head and neck resection free flap, that's probably not practical. Then we do sometimes use leeches for cases where there's a local area that looks congested or flap looks congested. We've taken it back, we've done everything we can, and it seems like it's holding on, but it's still congested for some reason.

Sometimes these little perforator based flaps, you might have somehow an injury to the tiny little vein as it enters the skin, so you can have transient perfusion issues in perforator flaps that might be temporized with leeching, but if it's a real venous clot, then leeching it is not really the way to go. You need to try and take it to the OR and fix the issue. These are really just in situations where it's a local flap, part of a flap perfusion problem, or you've already tried everything that you possibly can in terms of salvage operatively and it's not worked.

[Dr. Ashley Agan]
When you're going to the OR to troubleshoot, what does that look like? Are you taking down your anastomosis? Can you get an idea of how it's doing just by looking at it or I’m Dopplering it? What does it look when you're doing that OR take back?

[Dr. Eli Gordin]
You can get a sense of how it looks like. If you open the neck and it looks normal, after you've been doing it for a little while, you can get a sense for what a normal artery looks like. If there's a clot, usually, there's a bit of a discoloration, a purpleness. Arteries are usually white light pink shade. It gets a discoloration usually when there's a clot in there but depending on the wall thickness of the artery, you may or may not see that.

Certainly, you would see when you have a pedicle, and it's flowing properly, especially in cases where it's geometrically curving or looping on itself, you don't want to have it kinked, but sometimes we create a gentle curvature in the pedicle, so that it's going to where it needs to go, but not kinking, but then the whole thing expanding as it pulsates. It's not just rocking back and forth, which is more indicative of there being some obstruction and you're just getting a transmitted pulsation appearing thing from the fact that it's attached to a vessel that at some point does have some flow in it until that flow hits the obstruction.

You can just look and see whether or not it's expanding. You can Doppler it. If the neck is open, then you're able to lift the pedicle up and Doppler it with air underneath it such that you're not potentially picking up the signal of a deeper artery, which you can if you're just Dopplering it while it's flat against the neck. For the vein, likewise, you can probably more easily tell when there's a clot inside a vein because it's a thinner-walled structure, and then you can palpate a vein a little bit more easily. You take your little micro jeweler forceps and you can palpate artery, palpate vein. You can feel when there's a clot in there, especially for the vein it's pretty obvious most of the time.

You can do what's called a strip test, where you take two jewelers and you just gently you hold. For the vein you would be holding towards the flap upstream of where the venous drainage is coming from and then you milk with the other pickup. You draw your hand down towards the anastomosis and then you let go of the first one. You try and see whether or not there's venous blood passing through that area.

Then if you're not sure, then you have to take it down or cut a side branch. Sometimes there's little side branches that you clipped when you're doing the harvest, and then sometimes you can cut one on the artery and see whether or not there's brisk blood pulsatile arterial blood shooting out of the side branch or likewise with the vein and look for appropriate venous bleeding, but again, if you can't tell or you're not sure then the next step is you just have to take it down.

Unless it's a very late failure from venous thrombosis in which case the entire thing is clotted off, usually it's one or the other. In my experience, it's most commonly been the artery. Unless it's a late complication because of fistula or infection that affects everything, then you don't necessarily have to take down the vein. You might just take down the artery and the clot is going to be right at the anastomosis.

Unless there was some injury to the vessel downstream of the anastomosis, it's pretty much right there, so you just cut right next to your suture line or through your suture line you can just see the clot, pull it out, and then try and figure out why the clot happens because that's really the next step. Are we going to be able to salvage this? How long has it been? How long do we think it's been since we really detected the ischemia and what we need to change? Why did this happen? Is it a patient intrinsic factor? Do they have some hypercoagulable state that we missed or was it a technical error, which is oftentimes, especially early in your career is usually what it is.

You just redo it and then it's fine, but those usually occur 20 minutes, half an hour after you finish the original anastomosis. Just going back to the implantable Doppler, the one nice thing about the implantable Doppler, was you put that on right after you finish your anastomosis. Then it's there and you're listening to it as you're closing. Then it gets slowly quieter over time, and then you're like, "Oh," and you wait and you wait and it goes away. Then you have to reopen the neck, but you're already right there, and you're still in the OR, and the drapes are still up, so you find it immediately.

I think sometimes there's probably some degree of not noticing it until the patient's in the ICU. Then maybe the last thing you want to do is come back, especially if it was a hard case and it's late at night. Finding these things intraoperatively and Dopplering, like to Doppler, find the area that we're going to put a Doppler stitch on the neck or wherever it's going to be before we close the neck so that we are as sure as possible that we're Dopplering the appropriate thing, and then Doppler before we take the drapes down. Doppler before we leave the OR room. If there's going to be a problem you should find it within the first hour.

After doing the anastomosis, if there's a technical problem, or sometimes there's a plaque that's a little bit downstream of your anastomosis that just slowed things down enough to create a clot, so then just going back to what you're doing to try and salvage the situation. You're cutting back the vessels till the area looks clean and there's no more clots stuck in there.

If it's a localized clot, then you're not having to do TPA or flush the flap through with any thrombolytic agent if it's just at the anastomosis, then you assume first and foremost that there's either a technical problem with your suturing or perhaps your neck artery didn't have good enough flow, so you might check that again. Does it look like the facial artery or the superior thyroid or whatever you're using does that look like it's still two men as they say, or does it look like it's trickling out?

Then what's the blood pressure? Is the blood pressure 80 and it's trickling out or is the blood pressure 150 and it's still trickling out because that's a different situation too. Then maybe you want to pivot to a different neck vessel, whatever it may be, whether lingual or just something else, or just cut the vessel back more until you get good flow. Because step one is find a source of blood that's appropriate for your flap. Then once you have that, then it's looking into the lumen of the flap artery and trying to ascertain whether there's any indication that there could be atherosclerosis in there. Could there be a plaque more downstream?

You can tell usually just externally looking at the vessel if it looks irregular, if there's a marble appearance where you see yellow plaques and stuff like that through the wall and you can palpate it gently. You don't want to crack these things, so you have to be pretty careful. You don't want to squeeze a very atherosclerotic vessel and cause la crack in the plaque that then is going to become a thrombogenic stimulus.

Then just cutting back the flap artery. If that's not working to the extent that you can, just if you hook the vessel back up again and it thrombosis again, then you keep cutting the artery back until you can't anymore, and then at some point if too much time has passed, then you've reached what's called the no-reflow phenomenon where enough microcirculatory damage has occurred to the flap because of ischemia that it's just never going to come back again and all the microcirculation is thrombosed and it's over.

[Dr. Ashley Agan]
How much time do you have until then?

[Dr. Eli Gordin]
Theoretically, for a skin flap, six hours is,what's quoted as the upper limit of normal and it decreases with muscle and decreases a lot with a visceral, a jejunum type of flap. The problem is you never know when the ischemia occurred unless it's intra-op. You don't know if it's post-op day two, and you got called in the morning that the flap didn't look right. You have no idea if it's been eight hours or what.

[Dr. Gopi Shah]
Then for a flap that is salvageable, you take it back, you're able to cut back and re-anastomose, do you ever then put these patients on aspirin or Heparin afterwards or is there any rule for that post-op?

[Dr. Eli Gordin]
As far as evidence-based rule, I don't think so. The only evidence-based anticoagulation scenario is patients with hypercoagulable states, but I do usually put them on, if I thought it was an isolated anatomic or technical thing that we fixed, and I feel good about it, then no. If it's something that I just am not sure why this happened, but we managed to get things flowing again, then yes, usually we'll put them on heparin infusion at that point just because I have no idea why this happened in the first place and we want to obviously prevent it from happening again, but then it's trade-off between hematoma risk versus risk of re-thrombosis.

One thing I failed to mention is doing the thrombolysis and using TPA or something else like that. If you think that the clot has propagated pretty extensively throughout the flap or the last thing that you do, if your other stuff isn't working then you have to disconnect the flap from the patient's circulation because you can't inject TPA into the patient's systemic circulation. You can, but then you're risking a stroke or bleeding event where you don't have to. If you can just either disconnect the vein or clamp the vein and open a side branch and let all the TPA just out so that you can suction it up.

Sometimes you can use Fogarty catheters, these little vascular catheters with a little balloon on it to try and snake some clot out of there, but that, you're also potentially damaging the vessel when you're putting that in, and the vessel is narrowing, the more distal it goes. That oftentimes isn't a great solution, but it's another trick to just have.

[Dr. Gopi Shah]
As we are rounding it out, I feel like we've only scratched the surface.

[Dr. Ashley Agan]
We made a paper cut into this topic!

[Dr. Gopi Shah]
In the interest of time, any final thoughts about just how you think about free flaps and things that you would want listeners to know as the big take home points.