Biosynthetic Mesh--BTK
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Speaker: [00:00:00] Welcome to Behind the Knife podcast. We are the OHSU hernia team. I'm Maggie Bosley, one of the faculty at our, um, hernia and abdominal wall reconstruction center, joined by my partner Sean Orenstein, our fellow Amber Sandoval, and our chief resident Peter Ferron. Today we're gonna talk about bioresorbable mesh, and I think when we think about bioresorbable mesh, we know that there's a lot of new products out there, and we have to consider what are the pros and cons of using bioresorbable mesh versus synthetic mesh ver- versus a biologic mesh.

And when we think about different mesh products, in hernia surgery, we always wanna consider what's the right operation for the right patient at the right time with the right mesh, and you can see when we consider all of these things, it gets pretty complicated pretty quickly. And these decisions aren't always easy as we develop new technologies, new techniques, new materials.

This interplay gets even more confusing. And so if we zoom in [00:01:00] today specifically on mesh selection, I think the first decision we have to make is whether or not we're going to use a permanent synthetic versus bioresorbable versus a biologic mesh. And there's a bunch of different products within each of those categories that have different properties, which we'll talk about a little bit later.

But ultimately, when we're thinking about these newer mesh products and these bioresorbables, we're asking, "Is it worth it?" And when we ask if it's worth it, we're talking about specifically in comparison to the other options, which would be a biologic or a permanent synthetic And when these were developed, what we're really looking after is whether or not this gives us the best of all worlds.

When we think about, uh, permanent synthetic mesh, we often think about them in the context that they're very durable. They're obviously a permanent synthetic. They're often very cost-effective. But on the other hand, it may bring some concerns whether or not [00:02:00] these are intolerant to contamination or infection.

We have to worry about adhesion risk or potentially erosion and fistula formation. There's foreign body fear, some quality-of-life concerns. And on the flip side, if you consider putting a biologic mesh in a patient, these were originally, um, assumed to have a lower infectious risk with con- contamination and can tolerate contamination better and potentially have less erosion, but these are very, very expensive.

And a b- biologic can cost almost 200 times the cost of a, of a synthetic mesh. And so when we look at these bioresorbables, we have to ask ourselves, can this be the best of both worlds? And so before we decide really, are biosynthetics worth it, we need to understand some of the unique properties of these meshes and how long they stick around and what they really offer.

So, uh, Dr. Orenstein, can you kind of talk about some of the different [00:03:00] options?

Speaker 2: Absolutely. Well, you know, given it's a, a, a podcast here, there's limited discussion on all the meshes. You've given a nice intro into the wide variety of permanent versus biologic versus, uh, bioresorbable meshes. Let's focus on resorbable meshes.

That includes fully synthetic as well as biosynthetic. One of the more common classic ones that has been used over time is Vicryl mesh. And, uh, when we're talking about all these meshes, let me take a step back and think about things to consider. One is how long does that la- that mesh last upon implantation, and not only does...

how long does it last before it's fully resorbed, but what is the strength in that? That mesh is gonna last a lot longer even though its strength profile may degrade rapidly over several weeks to several months depending on the, uh, the, the, the mesh. And then also cost is an important determinant as we're picking these and this can make these repairs quite costly depending on the extent and size of the mesh we use.

So going down the list of some of these resorbable meshes, [00:04:00] again, Vicryl, one of the sort of the, uh, time-tested classic, uh, meshes that has been used in the past. One of the challenges with Vicryl meshes, though, is that its, its short degradation time. It's fully absorbed in about eight to 10 weeks, and not only that, its strength profile, uh, profile decreases quite rapidly.

75% strength at about two weeks, 50% at three weeks. By about four weeks, we're only looking at about a 25% strength of that mesh. That is not very long considering the the forces upon the abdominal wall after whatever use is, especially with a temporizing repair. Um, a- another consideration with Vicryl mesh is because it's rapidly re- absorbable, it's very inflammatory.

It induces and incites a significant and intense inflammatory response which can, uh, do a variety of things, including, uh, potential for fistula formation if it's on top of inflamed bowel, um, among other, uh, issues in that space. So for these reasons, while we used to use this quite a bit in the past, this has [00:05:00] fallen out of favor, uh, given that rapid degradation, uh, cycle and other, uh, issues, w- this has fallen out of favor and, and basically have used other, uh, materials instead of this.

Um, other... another, uh, product is that of BioA. This is a g- another fully synthetic but absorbable product. Uh, timeframe for absorption is about six months. Uh, however, the strength profile decreases significantly at about four to six week. We're only looking at about 50 to 75% of this strength profile. And while there probably is a, a time and a place for this material, again, I believe that the rapid degradation cycle is too rapid for supporting the strength and the forces of the abdominal wall for most uses.

Now moving on to bioresorbable meshes, and these are meshes that have... They are synthetic, that is, they're derived in a lab, but there's a, uh, biologic, uh, uh, derivation as well. Many of these are obtained by, uh, plasmid, uh, and [00:06:00] bacterial technology that, um, output various substances that then they use in a synthetic manner to, uh, weave or knit various materials for mesh production.

One material, one... excuse me, one mesh is called Tiger Matrix, uh, and Tiger, T-I-G-R, for that Tiger Matrix. Um, this i-interestingly is made of two different, uh, polymers. One is a rapid degradation which, uh, resorbs in, uh, about four months or so, whereas there's a second slowly resorbable fiber that lasts about three years.

And, uh, as far as the strength, uh, th-there is, um, uh, data that shows it lasts, it is fairly strong at about six months or so. Um, as far as this mesh, uh, is concerned, um, uh, we don't have any use of this product here in our facility. I don't know how widespread it is in the United States. I do know they have used this in Europe.

Um, to my knowledge, there's very limited data in the use of Tiger, uh, Matrix compared to other resorbable meshes. [00:07:00] And in addition, cost-wise, uh, and I forgot to mention this on the other meshes, the Vicryl mesh, we're looking at about a thousand dollars, uh, or so for the medium-sized meshes. The 30 by 30 centimeter Vicryl mesh is upwards of a couple thousand dollars for that.

BioA, we're looking at about four to five thousand dollars for the 20 to 30 centimeter range, and then Tiger Matrix, also about four to five thousand dollars or more for the 20 by 30 size, and then would go up based on the square, uh, uh, area of that. Um, uh, moving on to Phasix mesh, uh, which is one of the more, uh, commonly used biosynthetic resorbable meshes.

Uh, this has a, a very predictable degradation time of about 12 to 18 months. Um, and over that time, the strength does, uh, diminish as with any resorbable product. And with this, uh, similar to Tiger Matrix, we're talking at about a six, uh, to nine-month degradation time where it's probably lost about, uh, or at about 75%, or excuse me, is at about 75% of its [00:08:00] strength at about the, the six-month or more mark but does continue to last on for at least a, a year to a year and a half total.

Um, this is a, a little bit more expensive than the Tiger Matrix, hitting at around five to $7,000 for the 20 to 30 centimeter size and goes up from there. Um, Phasix mesh, uh, in its bare form can be used i, in an onlay or in a retromuscular or preperitoneal plane. They do make a coated version with an anti-adhesion barrier, their ST version, that can be used, uh, as an underlay or a bridged inlay for intraabdominal use.

Um, and then to last, to round out the list is a, is the newer resorbable mesh on the market, and that is Transorb. Transorb is another biosynthetic resorbable mesh. This one also happens to... is, is a Progrip, so it is a self-gripping mesh, and this lasts about three to five years, uh, from an absorption standpoint, and the strength is reported about five or so months.

Um, that said, it is a, it is a, is a [00:09:00] fairly new mesh on the market, so there's limited data with this, so we don't have, uh, long-term outcomes on this data. And particularly look- speaking of data, there's a lot of limited data on many of these products, uh, though some do have, uh, more robust data than others, which we will get to later in the podcast.

Uh, last couple things about these meshes is how do these meshes resorb away? And that is important because it can be impacted by post-operative, um, events. Uh, while biologic meshes typically resorb by enzymatic breakdown, many of these resorbable synthetic meshes degrade by hydrolysis. That is important.

Uh, for example, if a patient develops an infection in the area of the mesh, um, a biologic mesh can get rapidly degraded if there's a very strong, robust uh, bacterial infection with enzymatic breakdown of the product. This process cannot happen with these resorbable meshes as it does not degrade by enzymatic [00:10:00] breakdown, and it goes through a more predictable degradation cycle through hydrolysis, some of which go through the Krebs cycle and can turn into CO2 or water at the, as the end products.

So, um- Bottom line is there are pros and cons to all of these products. Each has a time and a place. They have differing cost analyses for these, and some hospitals have contracts which do uh, allow, uh, availability of these, where some hospitals may not have others available. Uh, the last thing to mention about these is, uh, eh, the way they're manufactured, many are actually manufactured like a synthetic mesh from a sizing standpoint and the, and the machinery.

As such, they can be trimmed to size based on the, uh, tissue planes being used and the needs for that particular patient and hernia

Speaker: Great. Thanks, Dr. Orenstein. So we know now that these meshes kind of all have different things to consider. We know some of their important properties, that they go away by hydrolysis, how they're [00:11:00] created.

But we know, as you mentioned, that they're kind of-- they're not cheap. They are several thousand dollars for a sheet of mesh, uh, in comparison to a, um, permanent synthetic. So how do we decide if it's actually worth it to use some of these more expensive meshes compared to a permanent synthetic? So Amber, can you take us through a couple things to consider when we're talking about is a mesh product worth it?

Speaker 3: Absolutely. I think the first step is defining what we mean by worth, uh, because in hernia surgery, we're often balancing the same core considerations. First, we're thinking about recurrence risk. Uh, at the end of the day, the goal is to still provide a durable repair, and if the mesh completely resorbs but the patient ends up with another hernia two or three years later, then we really have to question the value of that trade-off.

Second is complications, and that can mean a lot of things: wound complications, surgical site infection, seroma [00:12:00] formation, adhesions, erosion, fistula, chronic pain, et cetera. One of the main appeals of bioresorbable mesh is the idea that maybe we can reduce some of these long-term mesh-related issues while still giving the abdominal wall enough support during the healing process.

Third is cost, which is something that we've mentioned several times already, um, and this is an important part of the conversation because these materials are not inexpensive. Permanent synthetic mesh is generally very cost-effective, while biologics can be extraordinarily expensive. Bioresorbable synthetics tend to land somewhere in the middle, so when we use them, we need to feel like we're gaining something meaningful in return, whether that's a lower infection risk in a contaminated field, avoidance of a permanent implant, or potentially fewer long-term complications.

And then finally, there are patient and surgeon-specific goals that don't always fit neatly into a study outcome table. Maybe you're operating on a young woman of childbearing age. Maybe the patient has significant mesh aversion or prior mesh complications. Maybe you're dealing with a stage [00:13:00] abdominal wall reconstruction or a contaminated setting where a permanent synthetic just doesn't feel like the right choice.

Those nuances matter. So another way I like to think about this is in terms of assets and liabilities. What are the assets of the mesh I'm choosing? What advantages does it bring to this specific patient and operation? And equally important, what liabilities am I accepting in exchange? Because no mesh is perfect.

Every option comes with trade-offs, and ultimately, deciding whether bioresorbable mesh is worth it really comes down to whether the potential benefits justify those trade-offs for the patient that's actually sitting in front of you

Speaker: Yeah, I think that's a really good framework to think about meshes in general and our decision-making process around hernia repair.

Um, but a lot of what we've been talking about is very theoretical. Um, and so Peter, can you take a look and tell us a little bit about what the data shows around some of these meshes?

Speaker 4: Yeah. So the first thing I want to reiterate is just that we don't have a lot of high-quality long-term data yet. That's [00:14:00] probably one of the most important things to take away up front.

Uh, but here's what we do know. So in one of the biggest cohorts with the longest follow-up durations using Phasix, um, this study was published in JACS in 2022, and they reported on outcomes of ventral hernia repair using, uh, Phasix with up to five years of follow-up. This was 121, uh, patient cohort. Um, all cases were clean, and, uh, the patients had moderately high-- some of them had moderately high risk factors such as BMI over thirty-five and active smokers.

Most of these were sublay repairs, and at, at five years, there was about a twenty percent reported recurrence weight-- rate. Importantly, there were no mesh-related complications. And two of the main practical findings to take away from this study, um, that are consistent with some of the other bigger studies that have been published on bioresorbable mesh is that sublay repairs tended to do better overall and wider mesh [00:15:00] overlap mattered.

Um, another key study looking at BioA mesh in a contaminated setting was the COBRA trial. This study looked at about a hundred patients. The cases were mostly, uh, contaminated or clean contaminated, so CDC wound class two or three. Um, this one was a multicenter prospective single-arm study, and the mesh placement was via an open approach in the sublay or underlay position with fascial closure.

In this study, in, uh, cont-- contaminated or clean contaminated cases, the hernia rate with-- recurrence rate was reported at seventeen percent at two years, and the surgical site infection rate was eighteen percent. Notably, the quality of life significantly improved postoperatively. And some of the key takeaways from this study are that outcomes after the use of bioresorbable mesh in contaminated settings are reasonable and acceptable.

Underlay mesh significantly increased recurrence risk, and surgical site infections were associated with [00:16:00] higher recurrence risk overall. Um, when thinking about mesh placement, another notable study was the ATLAS trial, which reported on outcomes after specifically laparoscopic ventral hernia repairs us-using a coated Phasix mesh in the underlay position.

Um, and the recurrence rate in this case was fairly high. It was around thirty percent, especially with larger hernia defects lastly, briefly, just wanted to mention that there has been a meta-analysis published in 2024 looking at these, but, um, overall, this was pretty heterogeneous data. The follow-up was spanned between one month to 98 months.

It included 36 observational studies, and the bottom line here was that, um, the use of bioabsorbable mesh is probably safe with probably acceptable outcomes, but better data is needed, um, to draw any long-term conclusions. Uh, so just stepping back, the 30,000-foot view, uh, these meshes do seem to [00:17:00] perform okay overall, and, uh, like other meshes, technique is important, especially mesh position really seems to matter here.

Speaker: Yeah, I think that's a key insight that can often be missed when we're looking at the data. While we're trying to, uh, figure out what's gonna move the needle in terms of recurrence in some of these outcomes when we're picking different meshes, what we're really seeing here is that the mesh position really matters, the technique really matters, and the amount of overlap really matters for this patient.

So that's-- or this patient population. So that's a really important, um, piece for us to take away.

Speaker 3: Yeah. While we're focusing a lot on mesh type in this discussion, I think as you mentioned, one of the more important themes that comes out of the bioabsorbable mesh literature is that mesh position and technique still matter tremendously.

Honestly, across multiple studies, the signal is pretty consistent. Uh, sublay repair appears to perform the best, and in the data that Peter just summarized, [00:18:00] specifically the long-term FASICS data from Roth and colleagues, most of those repairs were performed in the retromuscular sublay position, and those patients had some of the more favorable outcomes in terms of recurrence and mesh-related complications.

Similarly, in the COBRA study, looking at the contaminated ventral hernia repairs, recurrence rates were higher when the mesh was placed in the underlay position. And then when we talked about the ATLAS trial, that evaluated the underlay placement of a coated FASICS mesh, and recurrence rates there climbed to over thirty percent, particularly in the larger defects.

So although the studies are heterogeneous and certainly not perfect, the overall pattern is hard to ignore. Sublay slowly absorbable synthetic mesh may actually achieve recurrence and infectious outcomes that start to look relatively similar to permanent synthetic mesh in carefully selected clean cases.

But once you move into onlay repairs, bridging, or underlay positioning, especially in larger defects, the recurrence rates become much less favorable. And I think that's a really important point because it's easy [00:19:00] to look at recurrence data and immediately attribute success or failure entirely to the mesh itself.

But in reality, the principles of abdominal wall reconstruction still apply and are the driver of a large part of success or failure in these cases. Tension matters, fascial closure matters, mesh overlap matters, and mesh positioning matters. These meshes are not magic, and they can't compensate for poor mechanics or technique.

So really, as we framed earlier in this discussion, it's not just what mesh you're using, it's also how you're using it. And I think that's an important takeaway when we talk about whether bioabsorbable mesh is worth it. In the right plane with appropriate overlap and sound operative technique, these meshes may perform quite well in selected patients.

But if we ignore those fundamentals, the outcomes become much harder to justify regardless of the mesh material itself.

Speaker: Yeah, I think that was a great summary, Amber. Talking about various techniques and all the things that we need to focus on when we take a patient to the operating room. And we've kind of highlighted some of these different [00:20:00] properties.

So now we need to try to decide what's the right patient when we're talking about right operation, right mesh. What's the right patient to use these in? Uh, Dr. Orenstein, kinda give us your thoughts on when you use these and when you think the right opportunity is.

Speaker 2: Yeah, this is, this brings us to the practical application of when to use these meshes, and keep in mind, this is a moving target.

As we accrue more data, as we gain more experience with the wide variety of these meshes, including the newer ones that are coming on the market, uh, this decision tree does change and evolve over time. But a, a few scenarios where, specifically we're talking about today bioresorbable meshes, where does these make sense?

Um, probably the, the, the first one is the biggest category that I use these in, and this is for temporizing or staged repairs. Um, let's say you're doing a contaminated CO case. Um, you know, there's, there's a low desire to put a permanent implant in there for, for risk and fear of, [00:21:00] of prolonged contamination and, and chronic mesh infection, or perhaps in the emergency setting.

Tra- trauma patient has an open abdomen perhaps, or a emergency general surgery case with a perforated viscus. These are high-risk contaminated cases, and they're very high risk for wound morbidity and implant infection. So these are not good cases to place a, a permanent prosthetic. Um, our, our primary goals is to save the patient's life, save their bowels.

Uh, we can temporize their hernia and come back to fight another day, and a biores- resorbable mesh is a, is a great way to temporize them be that, um, uh, as an adjunct, uh, to, um, uh, reinforce a fascial closure, say like an onlay, uh, without burning too many bridges there or any bridges, or perhaps as a bridged inlay or a bridged underlay.

Um, keep in mind that if we are bridging or if we're doing underlays, this does require an anti-adhesion barrier. We cannot place raw, uncoated meshes into, [00:22:00] into the abdominal cavity, and only some of these meshes are applicable for that, for that particular tissue plane. Um, uh, other things, you know, I mentioned contamination.

It could be an elective contaminated case that perhaps, um, the, the, the contamination and the bio burden is excessive, and we would not wanna place a permanent prosthetic in there. And, uh, you know, a non-permanent mesh, like ones we've talked about, would be very appropriate for this. Uh, a few other categories which are, you know, not quite as, as standard as the other ones- Things like hyperinflammatory states.

Uh, for example, patients that have already had demonstrated, uh, significant reactions to implanted foreign bodies. Uh, we've had patients that have had significant reactions to previous meshes, various suture material, and, uh, there is concern that they would induce a significant inflammatory and foreign body reaction to another permanent prosthetic, so a non-permanent product would be good.

Um, other patients, for example, that have, like, fistulizing Crohn's [00:23:00] or other hyperinflammatory states may be more appropriate to have a bioresorbable mesh. Uh, last couple categories to talk about are patients that come in with mesh fear, and, and, and fortunately we're getting more and more of these patients.

They're reading, uh, chat boards and having discussions online about the fears of mesh, and, and some of them have v- have very valid concerns, uh, about, you know, uh, implanting a permanent, uh, mesh implant in them. Um, and while many of them can be counseled as to, you know, what is the, the correct and appropriate mesh for them, uh, there are others that, um, it, it would be safe and effective to place, uh, a resorbable mesh in those patients.

And then the last category is that, uh, it's a category that doesn't get enough press, although we are discussing this category more at hernia conferences, and that's of women of childbearing age. Uh, women, uh, that have developed hernias. Some are asymptomatic, many are symptomatic, and, uh, while we do counsel these patients, it is ideal to wait until completion of all [00:24:00] pregnancies and childrearing in that we have, uh, tissue planes that we can use without further stretch, uh, and pain from, from pregnancy.

Um, these, uh, may be appropriate cases to use a bioresorbable mesh, uh, to get them through their, their years of childbearing, and then uh, depending on their outcomes after that, then we can always choose after those years to, to revise or do other hernia-related procedures after that. And, um, the last thing to consider though is, you know, globally sort of consider what is the long-term complications with permanent mesh.

Now, permanent meshes have been on the market since the 1950s and '60s. Many of these are time tested and, and widely used for a wide variety of various hernia repairs. But there's more and more data that is reviewing long-term complications, not just months, but many years after the initial implantation.

And so that is something to consider. And again, as we review more and more of the data, we have to weigh this balance [00:25:00] of, of the, the pros and cons of a permanent implant versus the pros and cons of a more costly, but non-permanent implant like the bioresorbable meshes.

Speaker: I think you make a lot of good points, and there's a few big takeaways from this.

Um, Amber highlighted that technique really matters. Peter highlighted in the data that overlap really matters in addition to technique and, and the mesh placement. Dr. Orenstein talked about a lot of good scenarios where these meshes make sense, and I think it all just comes down to using the data in front of you and, and treating the patient in front of you and making the best choice for them.

And I think we all look forward to the even longer term data that's going to come out from these meshes, and even potential new products, and figuring out what makes sense as we, um, move forward. But they are a very useful tool, but they're not a universal solution. So everything comes back to trying to make the best decision for the patient in front of you, choosing the right [00:26:00] surgery at the right time for the right patient with the right prosthetic.

So good luck with your decision-making process as you go out closing holes. And for now... Dominate the

day.