So, just like Dr. Tomei said, a complicated area of the spine to navigate is the cervical spine, and so we have a lecture devoted to navigating the cervical spine by Dr. Shibon. And hopefully... What? Your computer won't work. Yeah, it should be. Thank you very much. Good morning. Let's see. Great. Okay, so these are my disclosures. Also, I should say that Brain Lab has a slight influence on the talk because you will see many pictures from the company. Well, I would like to show you a few papers that are dealing with spine navigation for the cervical spine, mainly on screw placement, lateral mass, vertical screws, and also a few about tumor resection, then show you how we do it in Munich. We have intraoperative CT, 3D fluoroscopy, and different navigation systems, so we could also compare between the systems available. But also, we also have the passive robotic arm, which we will also show you afterwards in the hands-on section. And finally, an illustration of the robotic arm that is not released yet, that we probably will get by next year. So looking at the screws placement options, you will see in the literature that the different screw options, lateral mass screws, C1, C2, pass, vertical screws, or the lateral mass on the subaxial spine and tumor resection, and we'll just show you a few representative papers of those. Basically, you have either image-based navigation for the cervical spine, and now we have also the first reports of augmented reality in cervical spine. Otherwise, you can use template-based navigation where you have a patient-specific 3D implant, either you buy it or you can do it yourself, I'll show you that also. And some reports are showing stereotactic methods, but I will not go into that because it's really not an emerging technology. So for image-based, basically either you are working with preoperative CT scans or you are doing intraoperative acquisition, and depending on what you have, you will have different qualities of imaging. Best would be, obviously, intraoperative CT scan. So this paper looking at the accuracy of lateral mass screw placement between C3 and C7. Not randomized, but comparative study looking at 140 screws, conventional freehand method and 144 with navigation using surface matching, and they found no differences in nerve injury, spinal cord injury, or any other complication or blood loss. So we also tend to not use navigation for lateral mass screws because you don't really need even fluoroscopy for that, it's just according to anatomy. Looking at pedicle screws is a different thing in cervical spine. These are really demanding surgeries because you don't have really much space for error there. So in pedicle screws you see, this is a comparative study using 3D fluoroscopy, you see that the rate of badly positioned screws, grade 3 screws, here you see a real significant difference between freehand and navigation. And you can see here why that grade 3 screws, these are the screws that get you into trouble where the patient may have also neurological deficit or you may even hit the vertebral artery and do much damage. Looking at another paper, looking at intraoperative CT, it's a small retrospective study from Berlin, but nicely done. You see here excellent results, no misplacements whatsoever, but one of the issues that we talk about all the time is operative time. You see that mean OR time was almost three hours with a surgery that otherwise takes about 60 minutes. So it's obviously an issue, but safety of the patient is the most important thing and you see here that the accuracy was excellent. Now this is also a German group looking at the difference between intraoperative CT and surface matching, comparing two navigation systems. At first glance you see that there was no real difference, accuracy was very good, even so that intraoperative CT was almost better. But if you read carefully they also state that one of the patients in the intraoperative CT group had four CT scans during one surgery and the screw had to be revised. So finally no screw misplacement at the end, but again the patient had four CT scans and did have one screw revision. Here looking at augmented reality, this was published a week ago, also from the same group looking at the utility of visibility and the workflow of augmented reality using intraspinal lesion removal cases, which is nice, but again I'm not sure why you would need that, but time will tell and the technology is already available right now. Here looking at 12 patients with 3D templates, these are things that you can buy, this is Chinese paper. This is a patient specific 3D implant you can order according to a specific patient and you see here also very high accuracy and it's pretty cheap, so if you don't want to buy a navigation system because you don't really use or have to do particular screws of several splines so much, this would be a good alternative. Another paper, also Chinese paper using reverse engineering not only for the templates but also for the screw position and size, showing very good accuracy, also here $100 per segment which is very nice, or $50 per vertebrae, no complications, no revisions. Here if you don't have the time to order and wait for two to three weeks for the implant, you can do it yourself, this is a freeware you can download and then using a normal 3D printer you can, you know, prepare your own 3D template and use it on the patient also. With regards to tumor resection, you'll see that there are many case reports, not really big series, using, looking at the feasibility, the workflow, how you should do it, how to position the patient and how this helps you, this is very nice but still not a big series, but if you have it you should use it in the complex cases like we saw with Professor Tomei in the previous talk. So the way we do it in Munich is because we think that the cervical spine, at least C1, C2 is very mobile and anatomy is so clear we don't really use navigation for C1, C2, we don't use it for lateral mass but we always use it for all particular screws, especially in the cervical spine. And this is the setup, it took us about half a year for each system to learn how to position the patient, where to put the device, where to put the nurse and the camera and all. This is a big issue of line of sight, you see here that you don't want to have anything between you and the camera, so that's why with the O-arm we put the patient head towards the nurse feet, this is what the anesthesia, and you move the O-arm towards you when you need it and then push it back away from you. For the CT it's similar also here, you really don't want anything between you and the camera, it's set up differently here but in this way you don't have to move the camera from the left to right all the time during surgery. Fluoroscopy is the easiest part because you only put it inside the field where you're working only when you need it and then remove it but again here you need to be careful that because of line of sight issues nothing is between you and the camera. This is a nice case of a 14 year old, we had a radiation induced osteosarcoma where we used navigation for the posterior approach, here you see the setup, you are standing on the head, the camera is in front of you, there's nothing between the drill guide and the camera so no line of sight issues. And also navigation, in this case you see he basically had no pedicle which is in this case navigation was really helpful. Pitfalls here, we always do percutaneous, small incisions, lateral incisions for the pedicle screws of the cervical spine, we think you should not go through the midline because you wouldn't get the trajectory you need for the pedicle screws and also you need to be careful, also in this case the imaging, the preoperative imaging was not sufficient, here the C2 was not seen at all so we got lucky in this case, we didn't have to do a new interoperative scan but in some cases if you don't have a good preoperative scan you can't do surface matching. Here you see this is the interop position control and using the navigator you can also go in and know where you are at all times and do tumor resection. And afterwards we did a ventral approach here, we didn't think we need navigation because you had the disk space for orientation and he had a P-cage and then went for the treatment. So now we have also the robotic arm, we'll show you afterwards, this is really nice for the cervical spine because you eliminate all the movement during surgery, you have your trajectory, you move it, this is a passive arm, you just move it towards the operative field and then you can do the drilling and using a K-wire you can put your screw but this is still a problem as you can see here. You remove the passive arm and you put the screw freehand basically and you try to find your way again. So you move circular motions until you find, until the K-wire is still now or moving again then you have your trajectory and this is a big issue and a big, one of the biggest problems that's why we're working now with Brain Lab on ways how to put the screw through the passive arm in the same trajectory you used for the drilling. And hopefully by next year we will get the real robot looks like this, where you just push it, sorry. Well we'll show you the robot in a bit, but you have to move it towards the operating field and then the robot will continue with the final few degrees of movement for the placement of the screw. And that's it. I'm sorry about that. I need to find it again. So. So in conclusion, sorry about that again. So for lateral mass and uh, pa- pass screws for C1 we don't think you should use navigation, the anatomy is good enough. And it does prolong or surgical time considerably so if you have it and you have a big academic center for the residents it's great, also as a teaching tool, but you don't really need it. But you do need to use something for the particular screws of the cervical spine, they are just too dangerous if you do it freehand. If you have navigation use it, if not try with the templates. We don't have good data on that yet. And uh, please do not go into, through the midline, use percutaneous approach through lateral incision uh, for the particular screws. And here for tumor resection, this is good for complex cases, Professor Tomay showed the utility much better than I could. And uh, for clinical research in the robotics is still lacking so we need uh, more papers on that. Thank you very much. Yeah. The same one, the same one. Yeah. Yeah. What, well you could put it the other way around, but it's still very mobile so, yeah. Please. Interoperative monitoring you mean? Only for intermediary lesions, not for extra medullary only. Okay.

cervical spine

screw placement

navigation

pedicle screws

robotics