We'll sort of move down that path and let Rick share some of his early experience with his endoscopic discectomies, and then let Mike, the world's expert in craziness, show us how to do it with a robot with an endoscope, okay? Thanks, Rick. Thanks, Charlie. Good morning, everyone. That was an excellent talk, by the way, that's really nice. So as most of you know, for my whole career, I have been a tubular endoscopic or microscopic surgery, and I have been relatively anti-transforaminal surgery, more than relatively, I think. But I started experimenting with it again, so this is the third time that I've tried transforaminal endoscopy. First time was with Gary Onik doing the percutaneous endoscopic lumbar discectomies, and I didn't continue it because it just didn't make any sense to me. Second time was when we started doing visually guided transforaminal endoscopy, and when we started doing this, our tools were so primitive that you really couldn't get much done, so I abandoned it again. Things have advanced, and I'm trying it a third time, and I'm going to just talk about where I am with that and what's gotten better and what we can do. I don't have a lot of experience with this yet, but I don't think I'm going to abandon it this time. We've really made some progress in this area, so that's what I want to talk about today. I don't have any conflicts in this area. So principles of minimally invasive surgery are the same whether we're doing it transforaminally or through a tube. It has to be minimally invasive, and that means primarily that there's less tissue disruption, but the consequences of that are there's less pain, less blood loss, less ICU stay, shorter hospitalization. It can't be technically unreasonable, and that's where the transforaminal approaches become challenging because it is technically challenging. You've got to be able to do it in a reasonable operative time. You've got to be able to do it at a reasonable cost. Bottom line is you've got to get the job done. If you're doing surgery, whether it's open, minimally invasive, or transforaminal, you've got to get the job done, and you've got to do that without increasing your complication rate. So I've spent most of my career over here doing this kind of endoscopy and minimally invasive surgery, but recently I started looking at this again. So in the various attempts of doing minimally invasive procedures, we've tried a lot of things. We've tried chemonucleosis, the automated percutaneous, intradiscal electrothermally or IDET, hydrodiscectomies, radiofrequencies, laser discectomies, and visually guided transforaminal surgeries, what we're going to talk about today. None of these have made the cut, and the question is whether this one will now make the cut or not. When we go back to our principles, the transforaminal endoscopy satisfies several of these. It is truly minimally invasively. Technically it's a challenge, but not totally unreasonable. It can be done quickly, but it's maybe not so cost-effective initially. There's a big financial outlay to get this equipment. And bottom line is you've got to get the job done, and we're still proving whether we get the job done or not, and it does this with relatively few complications. The advantages, you can get access to the spinal canal and the entire foramen through a single six or seven millimeter incision. There's very little bone resection unless that's exactly what you're going there for, and I do specifically do sometimes foramen anatomies with this technique. It's totally muscle sparing. There's no blood loss. You can do it under local anesthesia if you want with sedation, can be done as an outpatient. They can immediately return to their normal activities, and there's essentially no infection rates. The disadvantages are you're working in a two-dimensional field rather than a three-dimensional field. You really need to know your anatomy because it's very hard to visualize your anatomy, especially in the early stages of the operation. It's pretty tough to get to L5-S1. If all of your pathology is posterior stenosis, for example, rather than lateral recess stenosis, that can be tough to get to. It would really be good if we had three hands to do this. Two hands is tough. The instruments are still limiting, although they're better than they were, and you put all of these things together, and there's a significant learning curve. It's kind of tough. So where did we start with minimally invasive surgery? The first procedures were actually done almost 60 years ago when Vals and O'Delaney started doing vertebral body biopsies for tumors, and they did this with a needle. They would stick it into the body. Immediately after that, Key and Ford started doing the same technique for discography so we could actually visualize the disc and its degenerative pathology. That led to doing chymopat pain injections, which is still being used in other parts of the world, but not at all in the United States. Then we started going to percutaneous discectomies. Initially these were non-visualized. Parviz Kambin was the first person to do this. He was working through a Krag needle and putting in the tiny forceps to do discectomies, and they were not visualized. They were blind, fluoroscopy guided, little tiny forceps, Krag needle. He was doing this through open surgery initially rather than doing it percutaneously. Then Gary Onik developed the automated percutaneous lumbar discectomy, which was a suction device that once you got into the disc space, you would just suck out disc for an undefined period of time. The theory was that if you decompress the central part of the nucleus, then you're going to take the pressure off the traversing and exiting nerve roots. That never really caught on very well, but then in the early 90s, we started putting cameras and lights on the end of these discectomies, and that's what this is. These are the light sources here. Here is the camera. We had a small, about two and a half millimeter working channel that we could put in small forceps and probes in order to get into the disc and remove things. Schreiber and Loy in 91 changed this to a bi-portal approach where one side would be the camera and the other side was the working instruments. It then became uni-portal, again with Parviz Kambin, and that eventually led into several different systems which are currently available now and which have gone a long way to being able to do more aggressive procedures. If we're going to do this, in order to be safe, we really need to know the anatomy. You need to know the anatomy very well, and you need to know the anatomy coming at it from a very different approach than we normally do, because we often, except if you're going to be doing a far lateral discectomy, we're not approaching Kambin's triangle that much, so we have to really understand what the anatomy is coming laterally. You want to work under clear visualization. You want to do it, you can do it under awake anesthesia if you want. I recommend if you're starting this, do it under general anesthesia. You always want to make sure that your instruments are moving away from the cord rather than toward the cord so that you don't slip and bang something. And you want to go, as we do all good surgery, in a very step-by-step procedure so that you always know what you're doing and what you're going to do next. This is an ideal first case to do. So this is one that Luis would do with a far lateral tubular discectomy, me too. But this is a great first case. That disc fragment is just sitting out there for you. It's easy to get to. You've got a big foramen to work through. And you can do this with your patient prone or lateral. The advantage of doing it lateral is it's very comfortable for you to work that way. The disadvantage is it's kind of disorienting at first. We're not used to doing that much surgery coming transforamally from the lateral position. So you can do it prone. The advantages of prone are that the anatomy is going to be in the same place that you're usually used to seeing it. So you can do it under MAC if you want. If you're doing that, you don't need neuromonitoring because if you bang the nerve, the patient's going to jump. You don't have to intubate them. You just give them a little nasal cannula for oxygen. Very short recovery time in the PACU. And you can talk to the patient if you need to. Under general anesthesia, I recommend using neuromonitoring so that you know if you're irritating the nerve root. You have a little bit longer recovery in the PACU. The patient is intubated. I recommend if you're starting these procedures, do them under general at first. I do, frankly, I do most of mine under general because I'm teaching and I'm allowing my residents to do part of the surgery. And if your patient's awake, they find that a little bit disturbing because your patient always says, you are going to do the operation, right, doctor, not your resident. And I'm pretty straightforward with them. I say, you know, this is a teaching hospital. We teach surgeons how to operate. I will be doing part of it. My resident will be doing part of it. If that's not acceptable, you need to go somewhere else. So the procedural steps, plan your approach, your access. First you insert your needle and guide wire. Then you do a sequential dilation. Then you do a sequential reaming. Then you insert your retractor. Then the endoscope. Identify your anatomy and then get the job done. Remove your herniation or do whatever you're going to have to do. So here, for example, is a patient in the prone position. In order to identify our anatomy, we draw a number of lines. This is the midline. This is the iliac wing. Normally I will also have a line going over the intended level that I'm going to work on, for example, 4-5, that would be here. And then you draw lines out here for 8, 10, 12, maybe, if you've got a really big patient, maybe 14 centimeters. And where those lines intersect is where you make your incision and start your needle to get to your target. So you're going to end up usually at about a 60 degree angle coming from cephalad to caudad. And depending upon which level you're working on, you're going to be anywhere from 25 degrees to about 50 degrees in this direction. So you insert your needle first under lateral and then AP fluoroscopy. And then once you've got that in position, you advance your K-wire through that. So the target you want to aim for is the superior edge of the inferior vertebral body. And you want to be in the mid-particular line. If you're too far out here, you're not going to get into the foramen well enough. If you get past the medial border, then you're going to put your needle into the dura. So this is probably the most important part of the procedure. So once you've got that, then you put your K-wire through that. And is that running? Yeah, good. And you get that down in position. And once you've got that, you ream the bone. And this is opening your foramen. So by the time I'm getting into actually doing the job, I've already opened the foramen, so I've got more working room. And then you go in and you identify your anatomy. Now, the first thing you see when you go in is just a gamish, right? You've got fat. You've got some ligament laying there. And you really can't identify everything. Once you start removing that, the first thing you're going to see is you're going to see the inferior portion of the facet, of the superior articular facet. Once you've identified that and your pedicle, now you kind of know where you are. And you can start removing pedicle and the inferior portion of the facet. And then you start seeing the lateral edge of the dura, like right here, and the traversing or exiting nerve root. So here was that case that we were talking about, a great case to start with. After I've dilated, this is my working channel. So I put my working channel in and I turn it cephalad. That's now protecting the exiting nerve root for me. So I don't have to worry about that anymore. So I can go in. I can probe. I can use my pituitaries. I can do a kerosene punch. I can use my drill. And I know that the exiting nerve root is protected. Rick, can I ask a question? Occasionally when I do a T-lift, I'll see a very low-lying nerve root that's really at the level of the disc, not up higher. Is there some risk in this part of the procedure? The risk is what Lewis was talking about. When you do this, I mean, it's easy to get this out of the way. Because you can either put it in on top and then turn it sideways, or you can put it in way up here. And so that's way above the nerve root. And then when you still turn it, it really retracts it out of the way. But that's the DRG. When you're retracting in the DRG, they have dysesthesia post-operatively. And that's one of probably the major complications that we see with this is dysesthesia. It always goes away, but it's really disturbing. And let me see. So here we are. We haven't done anything yet. We've done our dilation. I've put in my camera. And now I'm just removing a little bit of the ligament that's sitting there, the fat that's laying around. And then you can probe. You can verify that you're, in fact, at the disc level and that you're not going to get into the dura. And then you start actually seeing your disc. And in a second here, you're going to see everything get all kind of blurry right there. And that's because we just took out that disc. So you can get really big discs out through this. It's not a limited procedure in that regard anymore. And the other thing I often use this for is this is a patient who had scoliosis. We did a three-level, four-level correction. And then he developed just foramenal stenosis at one level. And that's probably from a little bit of bony overgrowth from using BMP. And we went in and essentially did just a foramenotomy from the outside going in. And we just drilled off the entire superior articular process to open that up and free it for his nerve. And I have Kerrison punches you can use. The size of the working channel is 3.7 millimeters. But they're now developing a new working channel that is 4.7. So we're getting to the point where we're actually having real instruments that can actually do a real work. They've developed techniques now to do lumbar stenosis as well as doing transforaminal procedures. So it's beginning to expand the indications. And maybe that means that it's getting worthwhile to spend the money and have it. So in summary, this is my third time that I've tried this technology. The first two times I abandoned it. Maybe I'll abandon it again. But I doubt it. We're starting to get some real work done with this. And it is really minimally invasively. Mike Wang's going to come up and talk. And he is a master at this. I'm still a novice at best. This time it appears to be pretty good. There is still a significant learning curve. But I think for some pathologies, this is going to offer a significant benefit. And so far, I'm pretty happy with it. Thank you. Yes, sir. Dr. Kessler, if you're revising somebody or doing it a second time for a recurrence, would you do that with a tube or would you use the endoscope? Right now, I would do it with a tube because I'm not experienced enough. Maybe next year I'll be able to come back and say, oh, this is... And it's interesting. When we first started doing MEDs, what we said was, this is good for virgin disks but you can't do redos. It turns out it's way better to do a redo minimally invasively than it is open. Maybe we'll have the same kind of experience with this, but I'm not there yet.

endoscopic discectomies

transforaminal approach

minimally invasive surgery

advancements in technology

procedural steps