All right, our next speaker is Jesus Lafuente from Barcelona, and he'll be speaking about cranial cervical junction instability. Thank you. Marjorie and Michael, thank you for the invitation. And yes, I will speak about the cranial cervical instability. And for that, we need to understand the biomechanics before. And the biomechanics would be that for C1, C0 and C1, the stability is based on the bone structures, particularly in the facet joint and the capsular ligaments, which are the most, the stronger ones at that level. And in C1, C2, the stability is based mainly on ligamentous structures, most of the ligaments cruciate and alar being the most important ones, and tectorial membrane capsular ligaments playing a second role. So to understand stability, we need to understand what are the players. And let's start with the bone. And with the bone, we have the occipital bone with the occipital condyle element, vascular, clivus, and the squamous portion. And also very important to know about the condyle, as if we want to do or plan to do condylectomy for some surgeries, particularly on the foramen magnum, we need to realize how much can we take out. And for that, we need to know the shapes and sizes where they come with. And we know that the oval size is the most traditional or more typical one, is a bigger one, so you can allow more condylectomy in this situation, whereas the triangular one, which is more common in men, is smaller. And if you have to do a condylectomy, then you have to be aware that if you do too much, you can cause instability there. The other bone players are the axis and the atlas. And as you can see, with the respective joints, the first joint is occipital atlas joint, which is a very strong capsular ligament, as I mentioned before. And the structure of the bone also plays a major role in stability at that level. Then we have the atlanto-odontoid joint, where the density is kept by the transverse ligament, one of the most, if not the strongest, ligament in the body. And then we play with the third joint, which is the atlantoaxial joint, which is a bit looser with the ligaments, particularly to allow rotation of the dense within that joint. So slightly talking briefly about the muscles, these play a major role, too, on stability. And we have superficial muscles like trapezius and sternocleidomastoid, which are the most external ones of them. And then we have deep muscles, which are two sides, superficial with splenus capitis and the splenus services, and a deeper one, which are the rotators, multifidus, and so forth. And the important thing there, as an anatomical landmark, is the suboccipital triangle created by the rectus capitis posterior major and the superior oblique and inferior oblique. This is a potent landmark, particularly to identify the third section of the vertebral artery. And also, if you want to, or you intend to do, the condylar screws, the floor of that triangle is, you will find in the superior part, the condyle. And then you can do your insertion of screws there for occipital-cervical fusions. Finally, ligaments, very important, perhaps the most important stabilizers in the craniocervical junction. We have external ligaments with ligament and nuclei, a very wide ligament going from the nucleus line in the squamous portion of the occipital bone down to T7, C7. And then we have an anterior and posterior ligaments, which are similar to the ones in the rest of the spine. They follow, in fact, all the way down. And the internal ligaments, perhaps the most important, most strong ones, as the eight main ligaments, the apical, both alars, a cruciate ligament with a transverse ligament as a transverse component, capsular ligaments, tectorial membrane, et cetera, et cetera. So with respect to the normal biomechanics, what happens at the craniocervical junction? You have to realize that the head is sort of a round shape. You have to connect it with the cylinder. And the amount of stability there, the amount of range of movement, are huge. And that's why we need severe or we need important stabilizers there, as we get 25% of all flexion extension and about 50% of all axial rotation. So those are two distinct joints, but they work as a single unit. And this is very important to understand, because if you're treating one, you may have to treat both. So you try to fix C0, C1, then you may have a problem as this function as a single unit. So the other important issue in the craniocervical junction, of course, is the amount of pathology, diverse pathology that you can find. And that's why it's very important to understand the anatomy very, very carefully. So the clinical picture, traditional, we saw in a previous talk, some of the clinical myelopathy with pain and sometimes deformity. And in some occasions, lower cranial nerve dysfunction, 11th nerve, 12th nerve particularly. And the therapeutic principle, which I think is important, is to reduce when it's possible, to fix when it's, to stabilize when it's unstable. And if you cannot reduce, you may have to do decompression. And the decompression can be from the front, through transorally, or from the back. So important in these cases, of course, the pre-surgical planning, I would like to emphasize on that. We need to do as many relevant tests that we can to have as much information we need. We need to know how the dynamics are working, so that we have a, we can prove sometimes that the instability on simple x-rays, functional x-rays. Also the MRI is very important to see the spinal cord. Also we need to see the vertebral arteries, which are the most important artery or vessel in that joint. And if you have spinal malalignment, then you may consider applying some cervical traction temporarily. But also, our pre-surgical plan includes how far are we going to go up or down. Do we stick to C0, C1? Or in the other hand, we need to go from occipital to lower cervical, subaxial cervical. So to determine stability at the C0, C1, remember the bones mainly. We have to draw lines, and we saw in the previous talk a case where you ran a line between the vasian and the spinolaminar line in C1, and you divide them to the C1, triage, and opisthogen. And this has to be below one. If it's above one, something is wrong, something is broken, and this may cause instability. And this is the trinellis classification for suboxation of C0, C1, anterior, supravertical, and posterior. This patient, of course, didn't make it, but these are more traditional ones, the posterior ones. You can manage to fix them, and you can save these guys sometimes anyway. Trinellis also describes the fractures of the occipital condyle in type 1, type 2, type 3. And this is a patient who was run by a car, age 46, which he has a bilateral. You can see a bilateral injury here and there. So this may be regarded as unstable. So to determine instability at the C1, C2, so the top one, C0, C1, is lines. In the C1, C2, are dynamic tests. And this is a traditional x-ray where you can see instability at C0, C1. And then you know, and you have to be familiar with the anterior dental interval and the posterior adantodental interval. And you know that in the AD, less than three millimeters is normal, more than three is abnormal. Similarly, for the PADI, more than 30 millimeters is normal, and less is a pathological one. So we have this case when we have to show two cases to understand. If these are reducible lesions, then you must reduce and stabilize. This is a 51-year-old man from Pakistan working in Bartholoma who was working in a building as a builder. And he came to our clinic with progressive myelopathy. This is the MRI. These are the dynamic x-rays where you can see clearly instability, but it can reduce on extension. And you can see there's a fascia joint subluxation, sublux when you extend the patient. We did an MRI. We can see a huge amount of compression there. It was amazing that he can walk into the ward, to the consulting room. And he had an abnormality there, but maybe an assault onto a down. And we treated with the C1, C2 screws because the rest of the spine was intact. And you can see the joint stabilized there and reduced. And sometimes we cannot do pedicular screws because high right invertebral arteries, as we have there. And we have alternatives in the C2, as we saw yesterday in the craniocebacal course we did, to introduce and stabilize the C2 vertebra. He has very huge options. And on the other hand, so we have a reducible lesion. And on the other hand, we have sometimes that they are not reducible lesions. And those situations you have to decompress and then fix on that level. So we have a traditional case. We don't see that many nowadays. But there's a 75-year-old female, seropositive rheumatoid on 83, unsteady head on 2006, allopathic gait on 2010, and unable to walk in 2012. These are the CT scans. You can see panels there and the dents sticking up in the foramen magnum. So she was a question of whether or not to operate on this lady. You can see a mass there, which is compressing. It's impossible to reduce this. We need trying any intent to reduce that can cause more trouble rather than any benefit. And for that reason, we need to decompress. In these situations, traditionally with rheumatoid, and to try to avoid the panels, we did a transoral surgery. And now you can do it through endoscope. This patient was done about four or five years ago. Nowadays, we may have considered only posterior instrumentation and see what happens. But she wasn't steady. She wasn't able to walk. So we decided to go with a bit more aggressive. This is how we do a transoral approach. Now we do this endoscopically, as I said. And you run the drill. And you remove part of the panels already. We are taking the sticking dents now with a drill up to we see the tectorial membrane, which is the last layer before encountering the dura. And you'll be seeing there just about the dura showing up there. And then we remove the rest of the bone. And then we flip the patient back. And this is a video showing how we do C1, C2s basically, an animation with relations to the vertebral artery. Of course, in the rheumatoid, this was a clear standard procedure. We have to realize that rheumatoids come with other subaxial pathology, like staircase deformity. And for this situation, if you do only a C1, C2, that will be a major disaster. So you need to back or plan your surgery before. And under those circumstances, rheumatoid arthritis, tumor, opiolel, clipel file, post traumatic aortic and congenital deformities. In those situations, you may have to increase your fusion up to the cranial bone, as you can see here. And in the cranial bone, of course, you can use all sorts of constructs. You can do transarticular screws, attach this to the major construct of the occipital-cervical fusion. And we have a lot of alternatives to make this fusion very rigid and successful for the patient. Nowadays, of course, we have improved dramatically on the medication. And now we rarely see these patients anymore. I haven't seen at least, I'm sure you. And we have also been expecting new technologies in this matter. We always thought that putting the cranial plate created unnecessary complications, such as head position and so forth. And studying the condyle well is important, as you can use a condyle screw sometimes to affix the skull to the cervical spine. I think it's important. But also, it has its dangers. We have to be aware of the hypoglossal canal, which runs around there, and also the vertebral, the carotid artery, and the jugular foramen for the jugular vein. These are important structures that we should not hit. Of course, immediately, we should not go to the spinal cord. This is the ideal positioning. And you may have to make sure that this is posterior, this is anterior, this is where the vertebral artery runs. You have to do it there. Yes, you have to avoid the joint. And also, from the top, you have to avoid the hypoglossal canal. Okay, so you have a limited space, but the anatomical landmarks are pretty standard. And I think it's a good solution to avoid the complications that maybe a cranial plate can cause. And also, the bone, the bone is, you can put up to 18 to 22 screws, millimeter screws, which is much more than you can put into the squamous portion of the occipital bone. Of course, with the minimally invasive, people who do minimally invasive realize the importance of the musculature as tension band. And when we do this operation, we strip all the muscles apart, and we want to see all the positions of, we want to see all the insertion for the pedicles on C1, lateral mass, C2. There's an alternative to do this minimally invasive. You have to do this through navigation, as you have to navigate the wound incision. You can see where we put two incisions laterally, and this is to avoid the stripping of the musculature and preserving the tension band intact, or nearly intact, as we do in the tubular procedures in the lumbar spine. And you can see some of the pictures here, just to not run. Of course, you don't have the possibility of putting bone grafts, so the suggestion here is to divide the C2 nerve root. I normally, when I do open procedure, I try to preserve it, but in this situation, you must cut it, so you have to see the fascia joint. You can drill it in, so you can create fusion locally there, and that gives you an extra way of fixation. So please beware of the vertebral artery, the most important structure in this region, as you can cause tremendous damage into the brain and also to the patient. And as I said before, C2 has a lot of alternatives to, you have a lateral mass, you can put trans-lamina screws, and so this is a big structure, so you can have other alternatives. So navigation, we limit our risks, which is also very important. And to conclude, the cranial-vertebral junction is a challenging surgical region. All people who does it realize that we can do perfect operations. Sometimes we can have serious complications. That's why knowledge of the anatomy is absolutely mandatory, and pre-planning surgery is absolutely mandatory too. And instability has to be established before surgery. And surgically, very important patient position, particularly if you're going to use, if you're going to increase to the cranial bone the fixation, you don't want any complication there. Pre-surgical planning, I cannot say that more often. And also, if you have some abnormalities in one of the sides, I recommend you screw first the right side and try and avoid damage into the vertebral artery, as if you damage it in the first time, you will not be able to do it in the other side. You shouldn't be able to do it in the other side. And basically avoid complications. Thank you very much. Any questions, comments, while the next speakers come up? Jesus, if the next speakers could come on up. Jesus, let me ask you real quick. So we get a consult every day about occipital condyle fracture, and the patient can't be flexed and extended like you've shown. And what do you do about that patient? They're polytrauma patients, they're immobilized. Anyways, what do you do to evaluate these people? For bilateral condyle fractures? It's the same thing. You see them every day. We see a patient every single day that we get called. There's a condyle fracture. What do you want to do? They're polytrauma, they're intubated. What do you do with these people? Well, depending on what the condition of the patient is, of course. But normally, if it's unilateral fracture, depending on the type of fracture, if it's a type three fracture, we would like to mobilize it with a collar. If it's a bilateral fracture, I am a bit more concerned, so I would consider a fixing at some point, depending on whether the patient is able to undertake surgery. But for type one and type twos, I do virtually little. I just put a collar and so on. Great, thank you.

cranial cervical junction instability

biomechanics

C1-C0 joint

C1-C1 joint

C1-C2 joint