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Endoscopic Lumbar Spine Surgery

Albert Telfeian and Jean-Pierre Mobasser

November 07, 2016

Transcript

- Today, we have Albert Telfeian with us from Brown University. Albert is the director of minimally invasive and endoscopic spine surgery. I'm Jean-Pierre Mobasser and I'm a neurosurgeon here at Goodman Campbell Brain and Spine in Indiana University. Welcome Albert.

- Thank you, Jean-Pierre.

- Glad you could join us and teach us a little bit about endoscopic spine surgery.

- Thank you very much for the invitation.

- This is obviously gonna be an interesting topic. It's a growing field, and we certainly saw a lot of interest at the society for minimally invasive spine surgery this year on this particular topic.

- Yes, it was exciting to see the evolution of endoscopic spine surgery come this far.

- Why don't you go ahead and start your presentation and if it's okay, I may interrupt you throughout it and just ask some questions that I think less experienced surgeons are gonna want to know.

- Thank you, Jean-Pierre. We're going to discuss endoscopic spine surgery today, which is really traditional spine surgery done in a most minimally invasive fashion in patients that are awake. I'm going to be presenting work that I've done in collaboration with other spine surgeons around the world. Particularly Ralf Wagner in Frankfurt Guntram Krzok in Richard Broda Germany. Menno Iprenburg in the Netherlands and Gabriele Jasper here in the United States. My other collaborators here in the United States have also been very instrumental in developing this technology. We're going to start with talking about the transfer reamer approach, which is an approach through Kambin's triangle. Kambin's triangle is the triangle between the exiting and traversing nerve roots. If this were the L45 disc space, we would have the L4 nerve root reaching under the hypotenuse of the L4 pedicle. And that would be the hypotenuse of the triangle. We'd have the traversing L5 root and we'd have the enplate of L5. When you're looking at it in this view and a direct lateral view, it looks like a straight forward approach into the foramen. However, this direct lateral approach isn't feasible for this surgery because of the abdominal viscera. So we really approach this from an oblique angle, which brings in the superior articulating process of the inferior vertebra as one obstruction to reaching the neuroforamen. This is from a cadaver study that I published in the journal Neurosurgery Focus in February of this year. And we're looking at the L5-S1 level here with the Fossette removed. We have the Si pedicle, the L5 pedicle, the S1 traversing nerve root and the L5 nerve root. And this is the area we have to target. I wanna go through a few cases and a step-by-step approach that make sense to other surgeons. The first case is going to be a left far lateral L5-S1 herniated disc and here's the sagittal T2 MRI. We can see the L4-5, we see the exiting L4 nerve root, but then at the L5-S1 level, we see a lateral disc herniation impinging on the exiting L5 nerve root. In the axial view, you can see the far lateral disc, and you can see that this would be a challenging case for spine surgery because the L gets in the way. So if you were going to do this through an open fusion, if you would do this with a minimally invasive approach, it would be difficult to access this with a tubular attractor. But this is how we would do this through a transversal endoscopic approach. And this fore scopic view, the patient is positioned prone, and I'm putting an external marker marking the disc space line. I'll mark the pedicle line. And then I'll mark on the patient's side a target line targeting the top of the disc space of L5-S1. And this is what the patient looks like position prone on a Jackson table. The patient's head is to the left, the patient's buttocks is to the right. This is the disc line, the midline, the pedicle line and this is the target line. And I've drawn three horizontal lines, 10, 12, and 14 centimeters from the midline to give me essentially a stereotactic grid of where I am. And typically for an L5-S1 herniated disc, I'll start 12 to 14 centimeters off the midline. And the patient's awake. I'll use local anesthetic and I'll start with an 18 gauge 25 centimeter spinal needle, like a lot of minimally invasive spine procedures. And I'm targeting the top of the disc space. So in this case, I'm just entering the disc space on the lateral view, but on the AP view, I'm just at the medial border of the pedicle of S1. Yes.

- Albert, so how do you come up with that oblique line that you put across from the, it looks like it's coming from the center and going down to the hip crest?

- The tip of that marker is going to be at the target. You want the orientation or the obliquity of that angle to be going across the isthmus or the parse. And the reason you do that is so that you can remove a maximally effective portion of that superior articulating process of the inferior vertebra. You want to avoid injuring the exiting nerve root. And so that gives you the best access to the safest portion of Kambin's triangle. Is that?

- A separate question is, how do you decide whether to go 10, 12, or 14 centimeters off midline and does that vary from level to level?

- As a rule of thumb when I'm teaching people how to do this, I'll explain that at L5-S1 12 centimeter from the midline, L4-5 11 centimeters from the midline. L3-4 10 centimeters from the midline. And those will be sort of rule of thumb starting points. Larger patients you'll have to move further lateral. And the idea is that if you're looking at the patient here, you really are starting at the point that if this was the patient was more of a rectangle where the flank meets the flat part of the back. So in this slide, you see I've advanced a K wire through the spinal needle, and then I'll make a four millimeter incision over the spinal needle. Remove the spinal needle, Jean-Pierre, do you have a question?

- I do. I wanna clarify this. These patients are awake?

- That is exactly correct Jean-Pierre. So typically I'll use verset and fentanyl for the patient, but in my practice, I need to be able to communicate with them because that will be my neuro monitoring. And so I'll prep the patient before surgery and let them know that I specifically need to know if they have any sensation or pain down the legs while I'm doing the procedure.

- Do you believe that EMG is an inadequate method for assessing the nerves during this procedure?

- There are a significant number of surgeons who do endoscopic spine surgery who use EMG and general anesthesia. I think that for surgeons that do endoscopic spine surgery, if you're very familiar with the anatomy, that that's a sufficient way to do it. In my practice, what I'm trying to do is give the patient an experience where they have the advantage of avoiding general anesthetic.

- Is there any literature that shows that patients who were asleep with EMG monitoring have a higher incident of nerve injury,

- No, there isn't.

- As opposed to people who are awake for the procedure? Okay. And is there a learning curve to doing these procedures with the patient awake with sedation? Because I know that some of my anesthesiologists may be uncomfortable if I were to try and do something like this at our Institute?

- That is a subject that there is quite a bit of literature on, which is the learning curve with endoscopic spine surgery. And the misnomer is that it's a steep learning curve. When in actuality, it's a shallow learning curve where you have to practice that technique over time and see incremental improvements in your success. And that is one of the challenges to doing this procedure. And typically someone who is learning the procedure will do a two day cadaver lab, might repeat that cadaver lab. We'll do a visitation with a surgeon who practices the technique. And the question about the hesitation of anesthesia providers in providing marked anesthesia for these kinds of cases, when they're unfamiliar with the cases of something I'll hear from around the United States. But it really is a minority view. We're all hear it's a problem. The solution-

- Sorry to interrupt, go ahead.

- To have that anesthesia provider talk to one that is very familiar with providing anesthesia for the technique. This line shows the beginning of the sequential dilation over that K wire. So this is just a Seldinger approach, just like if you were going to do a metrics tube type minimally invasive approach. And so you see in this lateral core scopic view, the first sequential dilator going down a road K wire, and then the next sequential dilator being stopped by that SAP. And these are the sequential dilators, and this is a crown reamer. So this is a tool that I will use to open the foraminal window. So a crown reamer cuts when you turn it clockwise and doesn't cut when you turn it counterclockwise. And so all let-

- Does that apply for bone and soft tissue or mainly bone?

- Just for bone removal. And so when it's passing through the soft tissue.

- But I mean the ability for it to not cut tissue, those teeth seem awfully sharp. So if you were on the dura, even regardless of which motion I assume there could be damage to the dura or the nerve root.

- Absolutely. When you turn this instrument counterclockwise in the non cutting fashion, that's principally so that a patient doesn't have pain while you're passing the instrument. But it is a sharp instrument. And so if it comes in contact with a nerve root, it is painful and the patient will immediately give you that feedback, that they feel pain. If you use this in an area where the actual thecal sac would be in contact, then certainly you could cut the thecal sac with this. There are other endoscopic instruments, blunt side shaver drills, endoscopic diamond drills that we use when we're near the thecal sac.

- Okay.

- And this was an AP fore scopic view, showing the reamer drill, just passing the SAP. And typically the safe approach would be to stop at the medial border of the pedicle so that you will not endanger the thecal sac. And this is the instrument tray with some of the instruments. This is the final working channel or final tubular retractor, and that'll be placed. And this is...

- Can you tell me the diameter of that final port?

- Yes, this final port is seven millimeters. It is exactly the size of a number two pencil. So it's really amazing doing surgery through such a small tube. This is a ball probe. This is a semi bendable grasper. So this is the final seven millimeter tubular retractor placed in the patient. This is me looking at the patient. The patient's head is here. There's a plastic drape. The patient's talking to the anesthesiologist, I'm using AP and lateral fluoroscopy during the case. This is the-

- Can you tell me Albert, when you go from AP to lateral?

- Is use the AP and lateral fluoroscopy primarily for the targeting with the needle. After that, I would use it to confirm where a ball probe would be over the pedicle. This is the working channel endoscope. This is the tip of the working channel endoscope scope. So this is about just over a six millimeter endoscope with a three millimeter working channel. And that is a two millimeter high definition camera. It has two ports, one for irrigation, the other for the egress of the irrigation. And the endoscope goes in the working channel, the irrigation is coming out the back of the endoscope. This is the port for the irrigation. This is the tubular retractor inside the foramen. And that's a ball probe underneath the S1 nerve. And so this cartoon is the orientation we're going to see the next video. One thing that you have to get used to is that this is endoscopy or arthroscopy, where we're able to turn the scope 360 degrees. So when this video starts, you'll see the orientation is that the exiting L5 nerve root, remember we're doing a far lateral left L5-S1 herniated disc. So when we look in, we're gonna see the exiting L5 route, and we'll gonna see the herniated disc. We remove the inferior portion of the SAP here. So if we could go to the video, so here's our orientation. This is the semi bendable grasper. This is the exiting L5 nerve root. And you see the white herniated disc. So I'm able to talk to the patient throughout this procedure just turning that tubular retractor more in line with the disc. And I'm able to reach with this bendable grasper underneath that exiting L5 root. So the advantage here for this kind of cases that this tubular attractor is of such small size, that I can safely get it into this tight space and decompress this L5 nerve root with the patient awake and do it safely knowing that I'm not injuring the nerve.

- It almost looks to me like the port we're working through is sitting on the nerve and rubbing up against it. Is that correct?

- So it does look like that, but it actually isn't, it is a very beveled port. So the open port part of the bevel acts so that it's not compressing the nerve. The tip of the bevel is inferiorly, and it's a 30 degree angled scope, so you're looking up. So it's almost an illusion that it looks like you're pushing on the nerve, but you're able to have that open part of the bevel protect or not pinch the nerve. And then if you want to protect the nerve, you could spin so that the bottom part of the bevel pushes it away. So it's a very well product design.

- Is there an annual biotomy defect in this particular case that was already present once you'd started taking out disc material and you're entering the annulus in that point?

- In this case, I couldn't tell you whether there was because I aggressively reamed and open the annulus with my reamer. There are cases where I have a very clear large pho gated, bilateral disc, where I'll do no reaming and I'll go in and you just see a very large fragment there, like a mushroom. And so you see that the epidural fat here is where you're getting into the actual space where the traversing nerve root would be. But this patient has principally a far lateral disc pathology and I don't need to really-

- Is that last remaining bit of white tissue that was in the upper position of the scope, was that disc material that's just being blown up into the canyon load by the irrigation?

- That's exactly right. And you don't always have to remove those. They can just float up the back of the camera. And that's the enplate of S1 that I've ream smoothly there. And this space here is the thecal sac or the epidural space where you see the top of the annulus here. And the ball probe here is what I'll do to reach over the pedicle of S1. So it really is interesting how small the foramen is that you can look from the exiting root down to the pedicle of S1 and all of this is accessible to endoscopic techniques. So it makes a great tool to-

- Let me ask, a lot of times patients when they're having surgery for these problems, their nerves are so inflamed and so sensitive. Do you find it just manipulating the nerves gently can have a significant impact on their pain levels during the procedure?

- Jean-Pierre, that is a great question. You can imagine that with this technique, the easiest case to access would be a far lateral disc, but in some ways that can be a very challenging case in a patient with an inflamed DRG. Because just by docking next to that DRG, the patient is in extreme pain. And you're not sure whether you're safely targeting. So sometimes those can be challenging patients. You don't wanna put them too far under and hurt their nerve, but you don't want to risk damaging the nerve because they're in pain when you're manipulating around it. So, excellent question. That is definitely one of the challenges with the-

- Albert, I'm gonna just summarize the case you just showed. A lot of times we have trouble doing bilateral disc at L5-S1 due to the patient's hip crest, the amount of space there. So there are a lot of surgeons out there that now do total facet ectomy and minimally invasive TLIFs for a crowded foramen at L5-S1. So it seems to me, one of the big advantages of this technique is for these foraminal discs and these foraminal stenosis cases, being able to really treat and free the nerve up without necessarily committing a patient to a fusion.

- That is exactly right, Jean-Pierre. And I'll have many of my neurosurgery colleagues now refer these patients to me for this type of surgery so that they won't have to.

- What percentage of your cases would you say are foraminal type disc, which to me, this seems the ideal technique for? Or is it just that you've gotten so good at this technique and technology that you've slowly expanded to a large other variety of cases and that's basically taken over a lot of other cases you used to do in a different fashion?

- Well, both things that you're saying are exactly correct. On one hand, my practice is biased because I'll see a larger number of foraminal or far lateral disc herniations for this type of surgery, because they're referred from other surgeons. And so it won't be a percentage that reflects the actual incidence of the disease. But what has happened in my practice is that I have grown so comfortable with the endoscopic technique is that I will try to apply it to other pathologies that seem that they would be accessible. Principally, this is my research interest is what advantages endoscopic spine surgery has to other pathologies, other than disproportionately.

- It looks like we're gonna start heading into the other uses. So I'll let you start with the next case.

- Okay, we're going to go through a few other basic but illustrative cases. So the next one is a left L2-3 caudally extruded disc herniation. This is interesting because this isn't foraminal pathology, it's canal pathology. This patient has an L2-3 herniated disc inside the canal, medial to the pedicle of L3. And this is a patient like you were referring that has extreme pain. The patient's been in the emergency room twice, is begging for surgery immediately. And this is the trans isthmus approach I was describing. So I put a needle in already a K wire, and this is the first dilator. And I'm targeting initially the superior enplate of L3. This is an AP view just over the pedicle of L3. And now remember the pathology is down here. This is the vinyl tubular retractor. The pathology is still here. I'm still quite a ways away. The ball probe now is reaching around where the pathology is. This is a bendable grasper where I'm starting to remove some soft tissue. And now I'm able to get the ball probe over here behind the pedicle of L3. And this is now a grasper really where the top of that extruded fragment is. And if we can go to the video. And this is one of the challenges when somebody is starting endoscopic spine surgery is. What you're looking at when you first get the camera in. This tool is a radio frequency probe, it's our bipolar. And what you're seeing here is remember, this is the left L2-3 foramen. So here is where the pedicle of L3 is. This is where I've used a drill to remove a portion of where the superior articulating process meets the pedicle. And then I'm seeing this large fragment of disc. It's just a white fragment sitting there, medial to the pedicle. So 98% of what you do in endoscopic spine surgery is targeting 'cause you can't remove something you can't see. And you can't see something if you're not in the right location. And you'll see the bleeding here, which is the epidural blood vessels, the epidural venous plexus that you have when you're inside the canal. And here you see for a second, the residual bone of the SAP that I've reamed off drilling the top of the pedicle. And just allowing me to access that extruded fragment. I can shoot an AP or a scopic image here to confirm that I'm medial to the pedicle and that I'm at the medial wall of the pedicle. And this is while I'm talking to the patient. I can poke on the nerve and ask the patient when he feels in his leg. And one question I'm often asked is how do I know if I've done enough? I can ask the patient, do you feel that pain anymore? I'm just going to turn my light back on.

- Albert, can you tell me where the nerve is in relation to the fragment right now? Or is it more of a not a direct visualization?

- So right here, what you see is that little pink area right there will be that just the fat and the blood vessels that are right against the traversing L3 nerve root. But here is an example where you're not seeing a clear skeletonized traversing nerve root. And many times what you'll see in this view because of the 30 degree scope is a thin portion of the bottom of the nerve. And so this is what becomes the view that you see for what the expected pathology is. So if you're targeting the disc fragment, you're gonna remove the disc fragment, but you might only see the inferior portion of the traversing root. There's other cases where you'll need to skeletonize that route and you'll see it more clearly.

- Okay, so I've got to ask you while we're on the case that you just showed that in my hands and in my practice, a disc medial to the pedicle wall that's migrated, why wouldn't I just do a tubular diskectomy putting it just medial to the pedicle drilling the lateral legend of laminin coming right down on the disc fragment and visualizing it directly? Do you think that what you're showing me is a better alternative, just an alternative or a more difficult alternative, except for advanced users?

- I think that the case I just showed you is challenging for the fact that that patient called my boss. And my boss is Thiago Caslon. He called my boss the next morning to tell him that he had run three miles. And so one of the challenges with this kind of surgery is that it's so minimally invasive patients aren't really in the frame of thought that they've had surgery. And if you did a tubular diskectomy you probably, when I used to do cases like this in that way, I didn't have patients running three miles in the morning after surgery, less than 24 hours. So one of the challenges is reminding patients that this is real surgery. That even if it's done in an almost percutaneous fashion, that they have the same risks as an open procedure. But certainly the issue you bring up is that you might not wanna make this your first case if you're starting endoscopic spine surgery. And so typically what I do is when I'm teaching people these things they're texting me pictures of cases from around the country about what they should be doing and how they should be doing those first cases. But this is maybe not a first case for somebody's doing endoscopic spine surgery.

- So let me ask you though, a little more pointed, because obviously you're an advanced user, and you've gotten to a point where you're comfortable knowing that you've got the fragment, knowing that you're reaching down medial to the pedicle, knowing that the nerve is decompressed. But for me, who's equally comfortable doing this minimally invasively through a tubular retractor where the incision may be two centimeters instead of nine millimeters. And the patients are, it takes an hour to do, and they go home the same day and they're up and active. I'm trying to see, is this a better procedure or just another alternative for this particular case? I see the value for a foraminal disc. And I see how you could say potentially that's a better procedure for the patient, but in this case, I don't see it as clearly. Is it just another alternative?

- Yeah, that's exactly right, Jean-Pierre. That's my opinion that essentially what it is, it's the same surgery, except I'm using endoscopic visualization. Both cases are a diskectomy, both require some bony removal. This might be through a smaller incision. And the advantages to this kind of surgery when you look at them will be less blood loss, maybe quicker back to work, back to life, but the outcomes are the same. There's not an advantage outcomes wise to do it this way. So if you're more comfortable doing it through a microscope and a tubular retractor, that would be the best way to do it. But I think that we as patients as well, will choose the way we want it done. So the average patient today comes a little over 100 miles to have this procedure with me. So there's professional athletes that will seek me out because they want the quicker back to life, maybe an advantage is less scar. We don't see as much scar with these kinds of procedures, but I don't think of this as the evolution that it's better than a traditional minimally invasive approach. And just like some people would say that the tubular retractor case, isn't really an advantage over a non tubular retractor case, even though there are some things that we think are superior to it. But when you look at the outcomes, they're very similar.

- Yeah, and you brought up a good point. Are there MRIs and studies that show, I would imagine that the scar tissue is less, are there MRI studies that show this?

- There are not MRI studies, but those of us that have done a thousand and more cases, we get together at special endoscopic meetings. And we all have these cases where we go back and do an open procedure because somebody has a different pathology or a reherniation. And what is odd is that you don't see the same scar. If I were to go back and do a disc reherniation after a microdiscectomy, the scar is terrible. It's amazing. But if I go do a microdiscectomy after an endoscopic, I essentially see no scar. And that is not something that is my own opinion, it's shared by many other endoscopic spine surgeons. We don't have MRI data on that, but it is very interesting phenomenon.

- I have a question when the real limitation for me as somebody who does a tubular diskectomy and the reason I use that is it's a very common minimally invasive technique. It's almost become pervasive. But the limiting factor in return to activities for me is not really anything related to surgery, but rather that annular defect and my concern that they're going to essentially extrude more disc or the existing anular defect. And so I'm really waiting for that anular healing process to occur, and that's my limiting effect. It's not so much of the muscle healing from the surgery because a day or two after the surgery, my patients are up and I'm having to hold them back as well. Are you saying that you think that there's a different issue with holding your patients back than that? Or is it just because they have even less pain that they're not paying attention enough?

- So I would say that if you compare an endoscopic to minimally base a tubular, it's the same amount of time. We're both waiting for the same annulus to heal. And with this technique, just like a tubular technique, you have to encourage the patients that although their skin is healed, that anulus isn't healed and they're at risk for reherniation. But I think I have to especially counsel them to be careful after this because it is such a small incision.

- Okay.

- The next case is a trauma case. It's a left L4-5 herniated disc and enplate fracture after a snowmobiling accident. And this is the MRI. You see the inferior enplate fracture of L4, and you see the disc protrusion on the sagittal T2. You see the L5 nerve root being compressed. And you can see here where the disc herniation is at the superior portion or the inferior portion of the L4 disc. And you have the L4 nerve coming out here. And this is the tubular dilator. This is the semi bendable grasper. And if we can go to the video. So this is a 23 year old patient who traveled several hundred miles because he was offered a fusion at his hospital. And we see the exiting L4 nerve root here. You can see how white the disc is, and now we're facing towards the foramen. And so you see the exiting root to the left, you see the foramen fat here. So I'll be able to take this bendable grasper, reach up underneath the annulus, start to remove that disc herniation. And this is a great instrument because it allows me to feel under that annulus and remove these chunks of disc. And I'll save the pieces of desk on a piece of gauze, so I can see how much I read note. And then I'm able to turn that and reach underneath the L4 exiting route.

- You know, sometimes these disc fragments are outside the annulus, but underneath the ligament, are you able to discern that visually or is that more of a tactile thing?

- So, both. This ball probe in here, I'm able to feel just like if we did with a dental or a blunt hook, I'm able to feel over the annulus. I'm able to use that ball probe and split the area between the disc and the annulus and hockey stick out fragments. So it really is the same technique, but just with a different visualization. All the instruments that I use.

- Are you able to have good tactile feed? Because I know that a lot of your instrument is running up against the cannular that it's in. Are you still able to feel distantly well with that?

- Yes. And that might be somewhat surprising is how much you have tactically even though you're working through a long tube. The next case I'm gonna show is an L5- S1 foraminal narrowing below a fusion. So the patients had a TLIF at L4-5 and now they've developed foraminal stenosis and an L5-S1 radicular apathy below their fusion. So typically in most of our practices, this would require extending the fusion. And we can see here how narrow the foramen is. And this is the endoscopic retractor underneath and on the lateral view. And this is the ball probe over the pedicle of S1. And if we go to the first video, this would be video three,

- I think it's four.

- Four, you're right, it is. You'll see that even after that initial reaming, this is the S1 pedicle going to the pedicle via SAP of L5. This is an endoscopic trill. So this foramen is extremely small. This is a guarded drill. And I'll the drill so that you can actually see the drill edges. And this procedure essentially won't be a diskectomy, there's the drill. This'll be a foramenatomy procedure. This'll take about 20 minutes to remove enough bone. And can you go to the next video Jean-Pierre.

- Sure.

- So after I'm done drilling, this is what it looks like. I have a pulsating S1 nerve root here. This is the ball probe. I'm able to feel the medial wall of the pedicle of S1. I'm able to ask the patient how her symptoms are, and I've decompressed this foramen. Now I published in World Neurosurgery this month, my two year prospective study of these patients who I'm doing adjacent segment disease above and below fusions. And all of my patients had success with the procedure. But by two years, 30% required me to go back and extend their fusion. So it allows me to symptomatically treat the compression, but it does not arrest the disease of adjacent segment disease. There's still the wear, and then the overgrowth. So I still have to figure out whether that makes it worthwhile, but that's not a small number, 30%.

- Albert, in that particular case, are you able to see... I assume you see the L5 nerve root exiting as well, but we just not able to see it in that video because we didn't look in that direction?

- Yes, that video was edited. So I didn't show the a L5 nerve root.

- Now I'm going to ask you a question that I only bring up because it's been a recent thing that I've had. Can you get into trouble if somebody has a conjoined nerve root that's exiting above the pedicle in Kambin's triangle where it's not supposed to be?

- I never seen a conjoint nerve root doing this. So it's a great question, but it is a rare phenomenon.

- Yeah, the only reason I bring it up is I had one last month. And like, even with your technique, when I'm going down and I'm in that lateral recess, I know my safe zone is right above the inferior pedicle. And there happened to be a nerve there coming off the dura and running out laterally. There were two nerves going out the same level one under the pedicle and then one at the level of the disc. And it was very lucky that I didn't injure the nerve root.

- It's a rare phenomenon. How I would approach this endoscopically really comes down to the fact that if my patient is awake, that is really what's going to protect me in those cases. And although I've never had a case where I had to bail out, because I couldn't seek my retractor, I certainly wouldn't proceed with a case where a patient had pain and I couldn't get around the nerve.

- So let's say that you're trying to put that reamer down. And every time you try and do it, or even actually the dilators before you get to the reamer and the patient's having significant pain, you would basically have to back off because that would never get better if there was a nerve there.

- Right, so in those cases, what I do is I back off and then I target the SAP directly. And then I'll go down with an endoscopic drill and then do my boney removal under direct visualization.

- Okay, all right.

- I just wanna go over some studies that my collaborators and I have been coming out with over the past few years, to give you an idea about some of the advances of endoscopic spine surgery and where it's going now. This first one is for the treatment of syndylolisthesis. And I think this is a good illustration. This is a former NFL player who on the pre-op image has an L5-S1 syndylolisthesis, a herniated disc. On the post-doc image, you see we relieved that compression and you see the endoscopic trough that's been drilled through there. And this is from the surgery that K wire, this is a curved dilator to get under and around that syndylolisthesis, the reamer. This is an endoscopic reamer and this is the the working out retractor inside the framing. So you get an idea of how big that foramen is now. Endoscopic drill to open up that area. This is a grasper to remove some of that retro pulsed enplate. This is some of the disc that's removed during this case. And then this is a series of 11 patients we published with another example of an L4-5 syndylolisthesis. And you can see here that after that reaming, you can see disc ligamentum flavum and that reamed SAP. Now you're only part way done at this point, when you enter with the endoscope, because with the Kerrison punch, you can remove this ligamentum flavum, take off the bottom of this until you see the skeletonized nerve root. And in this series, we had about an 80% good or excellent outcome in the patient's bass scores, but these were not patients that had instability, and they were not patients treated with stenosis. These were purely patients with syndylolisthesis and ridiculous symptoms.

- These were stable syndylolisthesis with no significant movement on flection extension. whose main symptom was coming from a neural compression.

- Correct.

- Okay.

- This was a case I published as a rescue or salvage technique after a minimally invasive TLIF. And Jean-Pierre, this was one of the things we talked about at the SMS meeting this year, which is disc preparation in the setting of minimally invasive surgery. So this is a 25 year old patient who had inner spinous clamps two level TLIF. And you see on this sagittal CT reconstruction, this is all herniated disc after his surgery. You see I've window to differently here. So he has residual herniated disc after the surgery and retro post TLIF cage. So my solution for this patient, I'm entering in with a needle just at that medial pedicle wall of L5. At the same time, I'm at the top of the L5 vertebral body. You see, I'm reaming my way in and simultaneously this is an endoscopic view and a fore scopic view. So when I say that ball probe is just medial to the pedicle of L5, you see them underneath the L5 nerve root touching the pedicle. This is a grasper removing disc. This is the same grasper reaching underneath that traversing nerve root taking out that large fragment of disc. This is the large fragment of the disc. This is the semi bendable grasper. A lot of the stuff I do is salvage work for other surgeries. This is a patient who had a minimally invasive spine surgery with heterotopic bone formation from BNP. You'll see his cage here. He has pedicle screws on one side, the set screws on the other side, and he has severe foot pain from L4-5 heterotopic bone formation. And this has been published as a technique for, I think, in the journal of spine technology for removing that with a metrics tube. But I am using a endoscopic approach here with a blunt tip shaver drill. So when you were asking me that question about the reamer being sharp, that's an excellent question. Because this drill has a blunt tip. So it pushes the nerve away as the drills edges open that foramen.

- Just to look up those last two cases that you just showed. Both of those cases, I would say, obviously you're showing the techniques and what you're capable of doing and how you can do it in a least invasive way for the patient. But we also looked at a couple of surgeries that really weren't well-executed. We saw graphs that were left on the posterior margin of the disc space that were not all the way anterior. We didn't see any segmental lordosis restoration in those cases. The bone forming behind the cage when the cage is so far back, all of those things could have been avoided with good surgical technique and good training. Wouldn't you agree?

- Absolutely, absolutely. I think that a lot of these cases seem to me that they have washed to the shore from the first generation of people doing minimally invasive spine surgery. Because we didn't know things when that BMP would cause heterotopic bone formation in minimally invasive TLIF. But this is just an interesting technique to solve some of these problems. But these problems do exist. I find that they're challenging patients to take care of. They don't want another large procedure, and they're not a lot of surgeons that wanna take on these cases that somebody else has had a technical difficulty. This next study was our experience with treating patients with persistent lumbar radiculopathy after instrumented spine fusion. And so you see the advantage to treating somebody that has failed laminectomy syndrome in the sense that they have a failure to decompress their lateral recess stenosis. So to be able to go in, this is the grasper, and I'm looking at it on FOS view to go in with our endoscopy tools, reamer shown here, and the scoping drill shown here, and a scopic chisel shown here, and this patient has a perforated pedicle screw. This is the exiting root. So very interesting how you can treat some of these complications of spine surgery.

- Albert, can you orient us on that last picture with the pedicle screw, the nerve and just sort of orient us? 'Cause I think that's a fascinating picture.

- Right, so this is the L4 pedicle, the L4 exiting nerve root. And this is just removing that really it's the top of the SAP below. So one of those pictures I showed you, we are focusing more down here. But if we walked up that Fossette from the external view, we could get all the way up to the superior pedicle. But you see the challenge. So we're not down at the disc below, like we worked decompressing. It was more like when I told you if I couldn't get through, I would walk up onto the Fossette. So you can look at wherever you can get your scope to go. Is that clear?

- Yeah, that's a fascinating picture. Especially seeing the screw threads exposed on the pedicle.

- Sure. When I started doing this high definition didn't exist. And things did not look as clear as they do in this picture. But this is what the advantage of a high definition camera is. The title of this talk is, endoscopic lumbar spine surgery, but obviously endoscopic surgery isn't confined to just the lumbar spine. So here's a series of three cases that published on the thoracal lumbar herniated discs. This patient is a woman who was actually referred to me because this was thought to be a tumor because it enhanced in contrast. She was in extreme pain. And the challenge with this is where it becomes like stereotactic spine surgery. So I have a large herniated disc, completely acquitted the foramen, but here her kidneys. And how am I gonna approach this safely? So I'll map out before the surgery, you were asking about how far off the midline, so it would be tailored for each level. And so I'll target seven centimeters off the midline to target that fragment. This is what it looks like with the ball probe on the AP view. And these are just some of the pictures from the endoscopic camera. This is the neural elements on retracting that the bipolar, this is the herniated disc fungating out into the endoscopic view. And this is the bendable grasper reaching underneath the annulus, finishing the diskectomy.

- Albert, it looked to me on that picture, like at this level, it's more of a, if you look at that image in the top right, that your cannular is coming in almost directly lateral, unlike the other ones where it's angled down towards the foramen.

- You'll see that this is actually, it's an extreme lateral approach would be coming across this. So this is actually quite a vertical approach, but the retractor isn't docked in the disc, it's really-

- It's not coming from a trajectory above or below. It looks to me like this is coming more parallel to the disc at this level.

- Oh, I understand now, Jean-Pierre, that's exactly right. As you march up the spine, that trajectory becomes more and more direct. So a patient with an L2-3 or L1-2 disc, the foramen first is so large. You don't have the SAP creating a window shade and you do come essentially a direct approach. I published this case. This is Ralf Wagner, my collaborator in Frankfurt. In World Neurosurgery technical note about doing a thoracic diskectomy, which is very exciting. This patient has a T8-9 disc. This is pre-op. This is post-op. This is pre-op axial, you'll see it here. The patient has a radiculopathy. And this is the diskectomy in the post-op image. And what that looks like is this is more five centimeters off the midline for the approach. This is where the pedicle is first when you dock, but now you see we're really medial to the pedicle here. And this is where the retractor is at the top of the disc. But endoscopically, now, this is where we are. Here's T8, here's T9, here's the SAP. So this is really done in two steps. You have to remove the top of the SAP and then more inferiorly on the SAP. So when you look in with the endoscopic camera, you first see this. You drill off that, and then you turn the camera slightly counter-clockwise to the SAP pedicle junction. You continue drilling until you have the disc exposed. And then there's the neural elements decompressed. And the reviewers were very appropriately wanted me to mention in this, this is not a technique for central disc calcified discs, but I think we all in our practice have those patients with thoracic radiculopathies that this might be appropriate for.

- How many of those have you found to this point?

- I have done two thoracic discs, both luckily successful. But several years ago, I did, it's two years ago now, I did the first thoracic spine tumor in the world, and this was in a 16 year old girl awake. And she had presented to me when she was 15, a cheerleader with this ventral T6 epidural tumor. And this is her postop scan. And I did a Costeau transfer septum for her, got a complete tumor resection, but the pathology was only a malignant tumor, not otherwise differentiated. Pathology was sent around the world. Nobody could figure out what it was. She just received radiation. And then she recurred like this chain of grapes. And so the first challenge was one, get more specimen. So here's the largest piece of this behind the T6 body. And so I went in endoscopically, this is what it looks like in an endoscopic view. And able to decompress at T6. And unfortunately this was a new links sarcoma and she eventually died from the malignant progression of this to the brain and spine. But what I was able to offer her was a palliative awake surgery where I could decompress, get specimen and do it in a way where she didn't lose a day of her life with a larger surgery. It was an outpatient awake procedure, which was very scary for me as a surgeon, but my neuro monitoring was that she could move her legs throughout it. This next case is another salvage procedure. It's a retibroplasty at L2 where the patient is leaked some net medial to the pedicle wall. And we know in our practices that having a patient with severe osteoporosis that you need to go do a laminectomy is a very challenging case. And that's the person you don't fuse. Here is that cement, patient has a severe L2 radiculopathy. And this was treated. This is a case of Ralf Wagner as well, that we wrote together. Where here's what it looks like after that endoscopic drilling, here is that cement drilling through removing it with the grasper and the skeletonized L2 nerve. A truly non de-stabilizing way to decompress that L2 radiculopathy without having to do a laminectomy. So this would be a case like you were saying, what's the advantage of this over a more open procedure. In this case, it's trying not to destabilize her. Dr. Wagner and I had published this case with treating a complication of total disc replacement. And we don't do so many of these in the United States anymore, but this patient said an L4-5 L5-S1 artificial disc. And in the L4-5 diskectomy, the surgeon got a fragment of bone in the L4-5 foramen. Now, the revision rate for TDRs is about 10%. And it usually requires a posterior fusion when you go to revise it. But Dr. Wagner, in this case used an endoscopic approach. And you can see from these endoscopic images using a drill, the grasper to remove that chunk of bone, and then the decompressed TDR. This patient went on to do very well after a total disc replacement. Recently, I published several articles with Dr. Guntram Krzok in Friedrich, Germany who invented a trans particular approach for endoscopic surgery. And this will be my last slide. And I want you to this hole in the pedicle on the CT scan. And this is on a cadaver model. So you know we're using a seven millimeter retractor and you know the pedicles down at four and five, you have a 15 to 18 millimeter pedicles. So we published two articles together. This one is on extruded disc fragments. So going through the pedicle to get this, this is that side shaver drill. This is what it looks like in there. And in these studies showed that the pedicle heals over a year. The two articles we published were for extruded disc fragments, and for Juxtapid set cysts. One of the patients in the study couldn't have general anesthesia, was very ill. Couldn't tolerate general anesthesia. So this is clearly a case where we're pushing the limits of endoscopic spine surgery. Because while you can do this through an open procedure, why risk fracturing a pedicle. But those of us that do these endoscopic procedures find us being sought out by patients who can't have general anesthetic. You have patients that have such severe CLPD, that they A, can't have general anesthesia and B, can't be positioned prone. So we can do these surgeries in the lateral position. And so this is maybe a not for primetime application, but it is interesting that it shows you what's going on with the technique today.

- Well, Albert you've certainly shown us the whole spectrum and it's really interesting how it starts and where it leads to. And I think we've seen this when you look at endovascular neurosurgery and where it started years ago and where it's progressed to. I have a couple of questions for you. The first one, is I looked at this technology a few years ago and said, this is gonna be done in some academic centers, but I don't see this going mainstream in community hospitals with community surgeons. Do you think that's right or wrong?

- You know, it seems to have-

- It's okay tell me if I'm wrong.

- No, no, I don't know the answer because it does seem to have some barriers that laparoscopic coal cystectomy didn't. That seemed to have a short window where only a few academic centers were doing it. And then it seemed to happen everywhere. It was almost overnight. I've been doing these procedures since 2005. So the technology we've all heard about it for a decade, but it still isn't happening in every center. A lot of this has to do with the technique has been evolving. I'm considered one of the advanced users, but it really wasn't until 2009 that I was really seeing major breakthroughs in what the technique could do. So I don't have the answer yet to say whether this will be practiced in every town. I do think it'll be more than just an academic centers. I think that now the biggest barrier was getting it to be performed at residency programs so that residents and fellows could be trained. Because there was the barrier, well, you can't learn something that you didn't learn in residency. And we all know the challenges to learning techniques that you didn't learn in residency. We look at lateral-

- That brings up something that I think is very important, which I've always said is these things are so much easier to learn in a residency or fellowship where you have somebody there with you, you have time to learn it. You can get over the learning curve during that training period. I feel like this would be something very difficult for a practicing surgeon to go do a weekend course, and then turn around and start implementing this in their practice with their patients. Do you agree with that?

- Yeah, I do agree with that, but I would also say I have some very gifted, minimally invasive spine surgeons who I've taught in a weekend who went on to do this very successfully and now currently teach the procedure. There are as a subset of minimally invasive spine surgeons that were born to do this.

- Now, one last question, before we wrap things up, one of the barriers in our area for this is the insurance aspect of this. And that is that insurance companies in certain areas are denying endoscopic diskectomy not because of this procedure, but because of the pain anesthesiologists and the mild procedure where they were coding these when they're sticking a needle into the disc and aspirating a quarter of a CC, a disc, and it all became somewhat of a billing question mark. And so these procedures are getting denied for that reason in our area. Do you have any thoughts or comments on that?

- Yes, to give you sort of up to the minute. I've spent about the last four years working with the AMA, developing a code for this procedure, that now comes out in the 2017 CPT code. And my experience is that I needed for these procedures to go to the individual insurance companies and make a case for the procedure to be able to do it in my area. And that really was one of the difficulties that not only you or other people felt I have felt myself. But hopefully we're getting past that.

- Well, I have to thank you for joining us. This has really been a fascinating subject, and it's one of the few procedures that makes me feel like I am behind the times and may need to adapt.

- Well, Jean-Pierre, thank you for your gracious interview. And I assure you, you are not behind the times.

- All right, have a very nice day, thank you. And to all our viewers, if you have questions and want to get in touch with Albert, I'm sure he'd be more than happy to have you and mentor you through this process.

- Thank you, absolutely right Jean-Pierre. Thank you.

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