And we're going to move on to MIS T-LIFT, essentially, with Dr. Su. Dr. Su is a professor of orthopedic surgery at Northwestern, expert in minimally invasive surgery, and we're happy to have him. He's also our co-director, too.
Great. Thank you, Paul. You can hear me okay?
Awesome. Let me just bring up our talk here. All right. Yeah.
Thanks again for having me. I really wish I could be in Seattle. I know it's the best time of the year to visit. We're really hoping that at some point we can get back to this very soon. So, yeah, we're going to switch gears.
I know we lost a few minutes with some of the previous talks. So my plan is just to go right into MIS TLIF. We'll talk about some of the reasons why I do it. some things that allowed me to change from open to minimally invasive rather seamlessly.
And then after some Q&A, I'll talk about a case that illustrates why I think MIS is better for patients, for patient outcomes. And we'll go through my workflow from soup to nuts as well. My disclosures are listed here. The only relevant one would be... probably be the royalties I received from a Stryker Tritanium cage, which is a T-Lift cage.
But I also use other cages as well. But most of my cage uses is titanium in nature. We also put together a MIS T-Lift bone grafting and technique guide with the help of BioVentis and the Council for the Advancement of Biologics.
You can see the members of the council here. that contributed to this circular and I'm happy to share this with Linda and this SSF group in terms of having a written syllabus so to speak as to what I'll be talking about. So as you heard from the excellent speakers this morning already there are reasons that MIS surgery should be considered. All of these are certainly considerations but the most important take-home message is that if you are proficient in MIS surgery then there is faster it's safer and it's more inexpensive. So it is a self-sustaining type of technique.
And when I talk about MIS, I'm actually referring to MIS-T lift, to O-lift, to laterals and all of the other techniques that you've heard. This is the type of patient that we need to struggle with because this is the most common patient that will come into your office. It's not necessarily your AIS patient or your degenerative scoliosis patient or have you, but it's a patient who has clear L4-5 Degenspondy, two-level central amperamel stenosis, symptoms are severe, really good indication for surgery, but the decision-making process really comes down to what is the best procedure for this individual and why. So the drivers of this debate would be to include and to achieve the goals of surgery, which would be a solid arthrodesis. We want to optimize clinical outcome.
We also want to optimize patient satisfaction, and that can come down to length of stay, amount of pain postoperatively, and function that correlates with that as well. And finally, we need to recognize that no two degenerative spinal incisors are alike. Even though some may have similar characteristics, we have to use these different characteristics and different qualities determined to the best procedure for the individual. So the algorithm for Degen-Spondy ranges from non-operative to operative, and even in some operative cases, a decompression alone can certainly lead to a good outcome.
Not every patient necessarily needs a fusion. But each of these patients with different kinds of procedures can all work well, meaning that they can all have very good outcomes depending on the type of characteristics that they have with their pathology. and I've done every single one of these procedures for a different individual with the same pathology. And so what makes them different?
Well, every disc height's a little bit different. The fluid in the facet joint, which may indicate dynamic instability, which then may lead to a decision for a more robust construct, and a better long-term outcome. Patients with positive sagittal balance not all need a PSO. necessarily, but we need to take this into account when we talk about approaches, whether it's anterior or posterior only. Obesity certainly will affect outcomes in a negative way.
And the patient's activity level, are they physiologic 60? Are they physiologic 50? That kind of activity level will put a large amount of stress on the construct that you give. And finally, what kind of symptoms are there?
Is it back? pain, leg pain only, and back or back and or leg pain. And so the continuum of treatment for me really depends on age as well as the characteristics and these are the kinds of procedures that I have performed for everyone who comes through the door. I do think that the MIS-T lift is a very powerful technique for a large number of individuals, especially those who are in between the ages of 50 and 65 years.
I don't think that Patients who are over the age of 70, for example, all need an inner body implant per se. If they just have central stenosis, then if you decompress that area, a T-lip may not be necessary. And then when do we do what? Well, these are all the characteristics I have in my mind.
I think you've heard from many of the speakers today that this will go to the algorithm of the decisions that you can make for future individuals. And this includes... the laterality of their symptoms, what exactly their pathology is, how many levels of stenosis that they have, how severe is it, and finally it comes down to the patient's wishes and whether they want a front back or a posterior only procedure that needs to be discussed with them. So why do we add interbody?
Well, I think the evidence suggests, in my opinion, that you can increase fusion rates with a posterior interbody versus a posterior lateral one. And in my opinion, the evidence does suggest this and show this. The rest of the reasons that we do inner bodies, including correction of deformity, increased stabilization, have more lordosis, have a better outcome, those are a little more controversial in my opinion.
And certainly, we need further data to definitively conclude this with the limited data that we have. But that being said... If we want to increase fusion rates, the candidates for an interbody fusion, in my opinion, would be a younger patient, one with an associated deformity, one with a dynamic instability, those who we do MIS for because we're not really doing a very good post-relateral fusion, and finally, non-union risk.
If you look at the exposure that one would have with an ALIV versus an open TLIV, and then you look at what we are looking through with an MIST lift, there is no question that there is a, for the surgeon, it's a poor access to surface area. And because of that, we need a biologic with a better handling property than what we're using for an A lift that's packed into a cage, what we're using for an O lift that's done in the same way, what we're using for a poster lateral fusion that needs to have some stickiness in a gutter region or more robustness. We need a biologic in this scenario that can be delivered through a very small tube, often two centimeters in diameter, and be able to be manipulated into a space even smaller than that.
And because we're not providing as much biologic, we need a biologic with more potency or better potency than the conventional ones that we see. So in my mind, if you are to do a MIST lift, You are really stressing the biologic environment or you are creating a stress biologic environment which you need a better biologic in order to accommodate for that. And so if you look at the corridor that we can typically manipulate, I would say, with a tube through a Wilsey approach and through angles, there's much that we can do here.
We can take the entire facet, we can take the contralateral frame out. And we can do a very good decompression to access the disc from a number of different areas. But there are again limitations.
There's no question in my mind that if you do an open T-lift and you have wide open view your angles to get the disc are at least 30 or 40 percent greater and it's just certainly more challenging when you have a small tube. In general, these are the keys to success in my mind. If you do an MIS T-lift, you really want to avoid nerve root injury. retraction, and irritation. I think most experienced surgeons who are on the panel will admit to you that when we first started doing some of these procedures, MIS-T lip in particular, the rate of radiculitis was quite high and much ado was made about whether or not it was the materials that we're using or the screws that we're using or the inflammation.
But I do believe that the more attraction you have in this area, the more you can get the better of the material. the more the patient can have radicular type pain. And so when you get more experience with this, you'll realize that at times your tube will be docked too medially.
And if it is docked too medially, you're going to have to pull the traversing nerve root a lot tighter and a lot harder than you would if you had a more gradual or more angled approach to it. And that's just one example of how I think one can limit some of the nerve root issues that we have. And I certainly don't hear about the radicular type issues after MIS-TILA as much as when this procedure first became popular.
And then, you know, adequate disc exposure and then avoiding pedicle resection during the MIS-TILA that I think is also important. When you dock your tube and you center it on the disc space, often the inferior edge of the tube will overlap the pedicle. So if you decide to take everything, all the bone and...
all the tissue out in the area of your tube that is allowing you to access the disc space and you're not careful, you can easily take away the pedicle and then that can make screw placement very difficult thereafter. These are pearls that the council came up with which I would agree with. Obviously the retractor placement is vital and I'll demonstrate that in a case very shortly. You want to know the length of each instrument that you're using. I do the procedure under a microscope, others do not.
But when you're using a microscope or have a tubular access, you really can't see how deep your instrument goes. You can only see the tip of the instrument that's visible. So you really want to know what point or at what point of the instrument you're looking at that is going beyond 30 millimeters, for example, because it's very easy to inadvertently. puncture the ALL and if your instrument is working in that environment, there's a lot of dangers that can occur.
And so knowing the length of everything that you put in will help prevent this. Blunt shavers are key not only for the disc space but also in case you do go through the ALL. Approximately 10 cc's of bone graft is what we would recommend to pack inside of a disc and to lead to a very good fusion. Again, for an MIS-T lip, it's a little more challenging than an open one, just because you're not taking as much disc out, in my opinion.
I see my fellows make a very small annulotomy when they start doing this procedure, and I'm always teaching them how to make a larger annulotomy, and if the annulotomy isn't quite large enough, then you use a kerosene in order to take away the annulus. If you do not have enough space or excursion to operate your instruments, to move your hand down, to move your hand up. to angle your instruments into the space, there's no way that you're going to be performing a good discectomy. And finally, instruments for packing the biologic are important.
I've seen a range of 10 to 15 different instruments that surgeons, excellent surgeons use all over the country, and I think all of them can be appropriate just as long as you think about which biologic you're using, how are you using that biologic, and what your workflow is in terms of packing that in. without wasting the material or having it come back to irritate the nerve. Just a moment on cost because we've talked about minimally invasive procedures and if they're sustainable and the only way they can be is to reduce the cost of surgery compared to open procedures.
The way we do this in the perioperative setting would be to reduce OR time. So most of the MIs, I'm sorry, all the MI surgeons that you're seeing on the panel here and most of the ones you know, around that we do surgeries with, are reducing their OR time compared to open. If you're not doing this, then it doesn't make a whole lot of sense because it will end up costing more.
Length of stay is important. I think this is the one measure that MIS T-Lifts have clearly shown a advantage compared to open T-Lifts. And that's maybe perhaps reducing the length of stay of one day on average. Now one day doesn't sound like a very, the very, you know, long period of time. If you're doing 200 cases a year, those are very big dollars when it comes to arguing for this procedure.
And then finally, if you're able to reduce infection in reoperations, or reoperations as a result of an infection, there's no question that you can save money from a perioperative perspective. So this study from Rush clearly shows, comparing 66 consecutive patients that MIS leads to less surgical time, reduced length of stay, and less anesthesia time. And there is a number that you can label as to how much money you save with an MIS-T lift.
If you're looking at post-operative studies, the study from Manorville looked at the surgical site infection rate and concluded that it's much lower for MIS than for open. It's not a reach to think about why this would be the case, but certainly those who are doing these surgeries can attest to And if you save $5,000 per case, you're talking about a huge amount of cost savings for the procedures that are performed, for every 100 procedures that are performed. And then finally, there are indirect costs as well. I do believe in my heart that MIS patients recover quicker in the immediate post-operative setting. And when I say that, we're talking about six weeks, maybe up to three months.
I do think that the outcomes are about the same after that period of time. But this study showed that MIS patients, if you have a shorter narcotic use, if you return to work faster, then these indirect costs can be realized as well. And so in general, there is a body of evidence to suggest that MIS saves money. And if it saves money, then it is better for the health care system as well as the patient. Quickly, when I talk about the efficiency of surgery and MIS-T-LIV, I'd be remiss not to talk about the evolution of navigation and how I use it in my practice and how I've made it efficient for everyone involved.
When we previously did percutaneous screws, all we had was fluoroscopy and a number of instruments, including jam sheeting, guide wires, and so on and so forth. The ORM came into play about 15 years ago when I entered practice, but at that time we were using the same instruments, jam sheeting, guide wires, and the like. Today we use navigation with much more efficiency, less steps, and has greatly reduced the time that I need to be in the OR for an MIH T-LIFT.
And along the way we've learned a few things including, you know, where to put the camera and to avoid having our staff having objects within the line of sight, being able to drape the patient and not the actual In this case it would be ORM itself and that reduces a significant amount of time. The use of power, the use of a table that like the new ORM Jackson tables that can save different levels of height where you're using it on a microscope and then using it with fluoro and then being able to use real time obviously self navigation in order to be able to place the screws. And so what it means is that in my OR when I am setting up an ORM, it takes, now it takes less than 15 minutes. I would say it takes us around 11 minutes from the calling of the ORM to the spin and even the removal of the ORM all in one fell swoop.
Because as the ORM is being removed, I can already start putting in the screw even before the ORM is actually out of the room, you know, in and of itself. Because sometimes they have to be maneuvered. on or around the case.
And so if you combine this with the fact that my colleagues who use fluoroscopy, they take about seven minutes per screw. And if you're using navigation and you're only adding about 15 minutes and you're doing a three minutes per screw, again, that doesn't sound like a huge savings per screw, but with a one level fusion that becomes significant. And then if you do 200 cases a year, it adds up as well. So this adds to the efficiency when we talk about the MIST level. And so before I go into my case, I wanted to identify two patients that I believe are serious home runs when it comes to this procedure in achieving a good outcome.
I think many of us would argue or would admit to the fact that if you have a one-level cervical disc herniation that's treated with an ACDF or a one-level lumbar disc herniation treated with microdiscectomy, those... success rates are really, really good. And I would argue that an MIS-T lip for this kind of patient is just as good.
If you've got an elderly gentleman who has L5 radiculopathy, and all it takes is just this one area right here in the foramen that we know we cannot get to through a conventional microdiscectomy, and then we need to take the facet out, these patients do incredibly well for MIS-T lip, and in my opinion, don't. do quite as well if they're doing it from a lateral or oblique or even an anterior approach. The second patient I think who is an excellent candidate in general is somebody who, and pretty common, is somebody who has had a previous discectomy and has residual foraminal stenosis. So in this scenario you can see that from the axial view that this patient has had a micro decompression. At one point they had resolution of their symptoms or improvement of their symptoms.
and then their symptoms came back. And then when you re-image them, you realize that there's still foraminal stenosis in that region. So an MIST lift in this scenario, just like the L5S1 foraminal stenosis from a posterior ossephalic complex, I think these two types of pathologies are very, very common in our patient population. And if you are able to do an MISC for them, they're going to be your bread and butter. You're going to have a very happy practice.
Okay, so that's my talk for pearls. And then I have a case presentation where we'll review workflow in a few videos in a sec here. But I thought I would stop for a moment just to see if there are any questions or discussion.
Hey, Wellington, it's Victor Chang. I'm filling in for Paul. He's getting ready in the lab.
So fabulous talk. A question for my, you know, we talked about radiculitis. What are your kind of strategy?
I mean, you touched on a little bit. What are kind of your strategies and pearls for avoiding that? In my own experience, I find that it's more common, like that second to last example where you showed the disc is collapsed, frame is pretty short. And then, you know, you get a few instances where you get like an L5 radiculitis post-op.
Sometimes it's delayed. What have you found to help kind of avoid that in your practice? Yeah, thanks Victor. Thanks for the question. So when, earlier in my practice, so similar to when, earlier in practice when I did laterals, the few times when I do a lateral and I, when I take the retractor up and you can see the nerve sort of slide into the view as the retractor is being removed, those are the patients in my practice that get radiculitis from the lateral.
And so the ones, the MIS-T lifts who have the same problem are the ones where I happen to dock the tube a little bit too medial. So usually you'll see in my talk or my workflow talk, I like to dock the tube where I can see the lateral edge of the facet joint. And if I underestimate...
where that lateral edge is and my tube is too medial, when I'm doing the decompression, I'm actually on top of part of the fecal sac and right on top of the traversing nerve root. In that scenario, I have just rotated or angled the tube just a little bit and then tried to pull the traversing nerve root over a bit just to get the cage in. But those are the patients that have radiculitis in my practice. So, um, The one thing I have noticed significantly over the past four or five years is that I'm taking a little bit more lateral approach for the individuals that I don't need to go into the lateral recess as much for.
And that improves the angle and reduces the nerve retention when we do the procedure. You know, other folks like folks who use BMP, for example, I'm using barrier technology. For me, I use MasterGraft, which is actually a bone graft. you know, bulking agent as well as a barrier for BMP, I believe can prevent some of that material coming out leading to the inflammation as well.
Okay, great. Thanks. There's a question here. I just saw, let's see, not using interbody in older patients and just using post-ferulateral fusion. Yeah, I just briefly went over that.
So if I have an individual who has a DGEN spondy with central stenosis and let's say has a collapsed disc, I think a lot of folks in my practice, a lot of my colleagues may do an interbody in that scenario. But in my opinion, if it's central stenosis and it's a relatively stable area, there's really no reason to pull on the nerve root and try to get an implant in to a collapsed disc because you're treating the central stenosis and you're fusing that patient. So fusing that patient posterolateral only, especially if they're a little bit older and you may not need as robust of a construct, I think is a good choice for that individual because you're not doing as much surgery and you can leave the construct and the more robust surgery for someone who actually needs it. And so yes, in that case, I would do an open poster.
Well, I would use like cortical screws or something like that, that would be minimally invasive and also provide that posterolateral fusion. So Dr. Su, that is another question that I had. So for the posterolateral fusion, what's been your experience with using cortical screws?
And my second question is, when you do your MIST lifts, do you arthrodes the contralateral facet or not? Good question. So the first question was about cortical screws. And I use these very, very often in my practice for the patient that I just talked about.
Cortical screws, in my opinion, do reduce length of stay about a day. I think it reduces the incidence of radiculitis because they're not even dealing with the lateral nerve root and the exposure in that area. And I think it can be effective and efficient. The negatives are that the fusion is not nearly as robust as a conventional posterolateral fusion where you expose the gutters. I think we all have to accept that.
But a lot of individuals don't need a robust posterolateral fusion in the gutters. They may need just a facet fusion. And so earlier in my practice, I would do 50 and 60-year-olds with this technique, and they would fail.
They would lead to a pseudo, and that pseudo would become symptomatic. I would say that if you have a symptomatic pseudo in like an a 75 or 80 year old, those, I'm sorry, if you get a pseudo in a 75 to 80 year olds, those tend not to be symptomatic. So even if, even if it's not as robust, it probably doesn't, doesn't really matter for that patient.
The second question was, when I do an MIS-TLIF, am I burying the contralateral facet? I am not. My, my partners do and my colleagues do. I think that takes extra time. I think that's extra time that is not required and not needed.
I believe if you have a good biologic for the inner body spacer, for the inner body implantation, then you don't need the contralateral facet and you can lead to just as good of an outcome. So it's really just about being efficient in the OR and how long you want to stay in there for that patient. Hey Wellington, this is Rick Hines. I have a question for you. I'm really glad to hear about corpus screws.
I use that for every case just about. What's so interesting is that a robot makes it easy for my PA to put a cortical screw in or any screw because it's just preoperative planning. But my real question is the elephant in the room between T-LIFT and lateral procedures is balance and lordosis.
And so I think there's a debate whether T-LIFT at L5S1 can really do the job or not. And is it a technique problem that we're having with not getting maximum lordosis with T-LIFT at 5.1? Or is it the technology that can't get us the appropriate lordosis? I've seen it every which way from it causes kyphosis to no, it doesn't cause any problem. You can get great lordosis.
But there's some debate. And of course, with lateral surgery, you always get great lordosis. Great question, Rick.
Yeah, so I would subscribe to the notion that if somebody has true sagittal imbalance, that the procedure for them is anterior, not necessarily lateral or posterior. Now, I would agree that lateral probably provides some more lordosis than a posterior, than a TILA, for example. I would agree with that. But most of the reduction or the improvement is really the disc height, not necessarily lordosis in that segment. Now, you are correct in saying and insinuating that the technology improvements have allowed us to gain more lordosis in laterals.
And I would 100 percent agree with that. But I think it is technique limited in some way. Now, the O-lift I'm going to take out of the equation because I think we're still learning about not still learning, but I think we're learning about the power of O-lift in terms of the results and outcomes with with lordosis. But it's pretty clear that if you do an A-lift. you're going to get the most lordosis compared to all of these other techniques, simply because the technique allows you to have that patient in the most optimum setting.
That may change though. I definitely think technology, we've certainly seen with laterals in particular, the ability to have hyperlordotic cages will increase the surgeon's ability to achieve lordosis. But at the same time, it's going to be limited when it comes to a posterior approach. I think that you can get lordosis with a posterior T-lift, especially with proper technique and using, you know, banana shaped cane, putting an anterior and then, you know, even compressing screws in the back.
But there is a ceiling for that. And so if somebody has positive sagittal balance, I am trying to shy away from a posterior only approach for that reason. And I think the evidence supports that as well. All right. There's.
One last question from the chat, and then we could probably go to your case. Could you discuss how far lateral from the midline you make your incisions for the screw placement versus inner body? Yes, I'll demonstrate that in a sec.
It's generally three centimeters. And unless the patient's really obese, you know, maybe 3.5 centimeters. But I think three centimeters is a very reasonable and rational sort of happy medium to put in screws and inner body cage. all right um yeah go ahead and go to your case okay sounds good good questions guys thank you okay so um i'm going to uh just talk about a case again it's in this circular that i talked about at the beginning of the talk that i'm happy to distribute um and um i can give you and so no need to take notes so sweet okay so this is a 45 year old uh female with a one-year history of left lower extremity pain in the l3 and l4 distributions I had a secondary symptom of low back pain. failed conservative management, and neurovascularly intact.
So this patient, in my opinion, is a reasonable candidate for MIS-T lift, primarily because of the foraminal stenosis, the disc height loss, the instability, and the lack of central stenosis. Not that you can't do an MIS-T lift with central stenosis, but it just makes it a lot more efficient, and you don't need to worry about decompressing the contralateral side and just focusing on the one area where you need to remove the set. So this is what my markings look like three centimeters from midline And I'm not taking an AP view when I'm trying to dock my tube. I traditionally Do the T lift first the inner body first and then the screw second and that really is predicated on the fact that I'm using alarm self navigation. It's just a little bit easier to do that after I do all the work inner body work and such so after the incision is made the the set is palpated and then the most important part of this procedure in my opinion is the placement of your retractor so not only do you want a good starting point to bisect the foramen but you also want it to be directed in an angle both medial laterally as well as caudally encephalad that will bisect and in our is in line with the disc space if you have a retractor that is not in the right place either because you're there's parallax with your fluoro or you've underestimated the amount of angle that you need to get to this space, you're going to get yourself in a lot of trouble.
And that trouble can come from all different directions. If you're too lateral, if you're too medial, if you're too high for too low, if you're not in the right place with the retractor, this tends to be a very long and painful procedure. Once your retractor is in the right place, then it becomes a very easy procedure because the corridor that you...
created allows you to remove all the bone that you need to decompress all of the neural elements to deliver the bone graft deliver the cage and then finally the screws and the rod afterwards and this all comes from a two centimeter area that's identified using AP or I'm sorry using lateral fluoroscopy and so you'll find that many surgeons who do this procedure will spend more time on the positioning of their retractor And again, even if it's in line on the lateral, you're not really sure if it's in line medial to lateral direction. That's when you have to start looking for the lateral edge of the fasetula, looking for the articulation of the laminectomy in the fasetula and looking for the lateral pars. The other thing I have found to be very helpful is that if you use a microscope and a fluoroscopy, you want them on opposite ends of the table.
And so anybody who has done this procedure like myself. knows that it's a very painful process when you bring fluoro in, you have to move the microscope out and vice versa. By doing it this way, your microscope can be stabilized at the head of the table and the fluoro can come in and out from the opposite end without interfering with the microscope going in and out of the table as well.
Now that we have some modern fluoro machines that allow the table to be at a operating height without having to move it up and down. These are just little things that will increase your efficiency so that you can do the one extra case a day where you're not in the OR for an extra hour. And they really matter significantly.
And so the OR in my room looks like this, where the fluoro and the microscope are on opposite ends of the room. And they're basically parked in that area. And so I don't need to call people in and out all of the time if I need fluoro or shadow or whatever, because everything's done.
So this is what it looks like, you know, in real time. If you look at it from the head and down to the buttocks area, this is the midline and lateral area. This is what it looks like after the tube is in the proper position. We're feeling for the lateral edge of the facet joint right here. We're removing the muscle tissue overlying the facet joint and then now we convert this entire facet and not have to worry about taking out the pedicle.
not have to worry about being too medial. And this can be done with an osteotome, with a burr, what have you. It can be done very efficiently.
This is Kamin's triangle that you're looking for that would match the surgical animation up top here. And so if you have this window and you're not retracting, you're traversing nerve root medially to get to that window, then this patient will not develop. radiculitis because you're not in that area, in that danger zone that would create that. So these are the things we want to be thinking about, not only nerve root issues, but we don't want to lead to an inadequate decompression.
In this case, the x-ray nerve root is up in this area. I teach my fellows and my residents that you don't necessarily need to see that nerve root. However, you need to know that the amount of bone that you've taken out is posterior to the nerve root so that nerve root can come back and forth. There are times where there's a lot of tissue and there's fleeting in the area of the nerve root so we don't necessarily need to see it every time, but just as long as there's room in that area then I know I can stop. And so this is a video of the actual procedure itself, we won't go through the whole thing.
But while this is all being done, we can get x-ray in very easily because it's on the opposite side. We can make sure that when we're doing our disc prep that we're not too lateral or medial. And being able to expose this area, you know, to do your discectomy and to do the decompression at the same time can then be very efficient. So this is the case. So from L3 to L5 there's foraminal stenosis.
We did the fascitectomy. I was using p cages at the time of this procedure even though I sort of switched to a 3d printed titanium. I do use BMP for a majority of the MIS T-lift cases. I would say that up until very recently BMP was probably the only biologic that I would trust in this environment and this is predicated on the fact that I just talked about how I think that this is a more stringent environment to achieve effusion. And when I put BMP in the front of the cage, I also pack Mastergraph behind the BMP because studies in my lab have shown that the Mastergraph actually does not bind to BMP whatsoever.
It acts as a barrier. It also acts as a barrier to BMP. bulking agent inside of the disc space and the cage can prevent the extravasation of the growth factor as well. More recently, I've been using a third generation synthetic. In fact, this week, I had to use it in a patient who has known active multiple myeloma, who I would recommend not using a active growth factor in, regardless of the controversies with cancers and such.
But there's no reason to use a growth factor in that environment, in my opinion. So a third generation said that then in my limited experience for the past year, I've been reasonably pleased with it as well. OK, so that's the case. Let's see. Let me stop the share here.
Any questions regarding that? I guess Osama's month isn't working. No, that was a great case example. I don't think we have any other questions. I just want to ask, is it hard to get those peak cages in there?
Are you constrained by the tube at all? Because I've seen people use a lot of expandable technology through tubes. What do you think about that?
Generally speaking, no. I just use like a quadrat tracker actually with a spotlight arm and that the diameter I use is 21 millimeters so two centimeters in my opinion is enough. You just have to make sure it's in the right place.
You have to make sure it's right in line with the disc space, that you've removed enough facet superiorly and inferiorly. Generally speaking, if you have removed all of the bone posterior to the exiting nerve root then that will give you enough height or enough space in order to put in as large as a 14 millimeter cage and we do that pretty routinely so um now uh there are cages that are have variable widths and so at times i've used a more narrow cage in the in the environment where uh you know you may not have as much room between the exiting the traversing your route sometimes anatomy just sort of ends up that way but typically we're using about 11 millimeter wide cages and able to put that in through the tubular axis. Again, it just comes down to how good your decompression is and being able to see the traversing nerve root and being able to retract it at least to a small degree will increase that space for you.
There is a question in the chat. If you dock your tube laterally, do you expose more bone immediately to observe the root before you're putting the cage or are you comfortable putting the cage in without seeing the root? Yes, good question.
No, I always... So... I don't have to see the nerve root, but I have to remove the bone, if that makes any sense.
And when I'm talking about this, I'm talking about this medially here, the traversing nerve root. Again, the exiting nerve root, I think when you do this a while, it really doesn't come into play. The goal of the surgery is to decompress the exiting nerve root, but as long as that decompress, you're really looking at the traversing nerve root to retract it slightly more medial in order to give you the most space for your T-lift. So the question is referring to the fact that, yeah, if your tube is more lateral, you have a more medial angle, you still need to remove the medial bone.
If you don't remove the medial bone, then the patient may have a pincer effect that leads to lateral resuscinosis and persistent symptoms. If you don't remove the medial bone, you're also, you may, this may lead to cage mal, or misplacement because you're not able to angle it medially enough. to get across the um to the contralateral side and that will that will lead to the best fusion type outcome in general and then uh there's a follow-up question if you do the inner body first are you concerned about the nerve roots being exposed when you play screws no uh because when i do the inner body i save the pedicles on both sides i'm not going into the pedicle um and uh And I think what this is referring to is that you have to put like an all tap and then the screw in after you've exposed the nerve.
In general, when we do the screws, it's two steps. We use one all tap and then we put the screw in. So I think the risk of having the exposed nerve root being in the surgical field while you have multiple instruments, that's really not a concern for me because of the way I do the screw technique.