Dr. Margetis gives rehabilitation professionals a current overview of Cervical Myelopathy. Review of the condition, case study example, and current surgical options overview.
Chapters (Click to go to chapter start)
Clinical Case - Intro of a clincal case study Degenerative Cervical Spine Disease - Overview of cervical spine disease Pathophysiology of the Degenerative Spine Disease Cervical Myelopathy Overview - Specific cervical melopathy insights for rehabilitation professionals. Cervical Myelopathy Surgical Options Overview - Review of the latest surgical options
present this topic to you today. I understand that there are many world experts in the field of spinal cord. So it was, it was not an easy task for me to come up with the presentation that I will try to keep their interest. And I understand that we also have many junior colleagues that they're new to the field. So I felt that we need to provide some more background information that they might find useful. So uh we we have to cover many topics. So I'll start so I'll start with a quick clinical case. So this is a 67 year old man with some balance issues and neck pain that goes up to eight out of 10. There is a small disc herniation that you can see here and the slide spinal cord for the formation of the axle cuts. But on the flexion extension M. R. I. You see here on the extension that the stenosis gets worse. Well, deflection, the stenosis gets better. You can see here the spinal cord, the CSF. So this is a kind of borderline case whether we should offer surgery or not. There are some factors like the spinal cord signal saints here that shows that there's some kind of uh you know, active inflammation going on in the spinal cord that will lead us toward surgery, but his symptoms have remained stable. So we have opted to closely monitor him and on top of all the other things, there is a degree of uh degree of uh I will call the stability by hyper mobility of the cervical spine. And you can see that on the on the lateral views. There is a degree of scandalous thesis until we actually measure that is 1.8 millimeters. And when he's flexing the head That degree of smart analysis goes up to 3.5. So again a very borderline case and um we have opted to monitor him after explaining in all the options that both the search collapse and the non operative options. But the real Um you know the real issue here is that we're not certain what is the best option for him. So someone might consider the previous cases kind of esoteric like neurosurgical dilemma that probably doesn't apply to you know to rehabilitation doctor or two. You know general general medical doctor. But there's this recent study that they're talking that the prevalence of a symptomatic cervical spinal cord cooperation can be as high as 24%. So this M. R. S. Like the other we saw might be much more common in general population and thus the threshold for getting an M. R. I. S. And the availability of M. R. I becomes higher higher. We might be seeing more of these findings in many cases that might be incidental. So it's important to be familiar with the topic of spinal cord cooperation path. E. And this study they argued that the prevalence of milo party might be as high as 2.3% in the general population. Uh I will take that number as an absolute number. But it's an indication that this is an incredibly common disease that I think that would slow be familiar with. And it's now regarded as the most common cause of spinal cord dysfunction. And actually there are some people who call the generative circle milo apathy as spinal cord injury in slow motion because we're dealing with spinal cord danger. But in a more like chronic uh way of of developing. And somebody might say that the previous patient had mild symptoms didn't really affect that mass his quality of life. But it is the case with all the DCM cases and this study a few years ago, they actually saw that for the sf 36 with a common quality of life metric the cervical spine. Geological, I love coffee. And a quick note here this condition can be referred as CSM or DcM were basically referring to the same thing. So they have a very low quality of life, both in the physical component. Also the mental component. It was only the back pain that had a lower mental component and all the chronic failure that had a lower physical component. So, again, I will take these numbers as absolute comparison between the pathologist. But it is an indication that my locality can definitely have a big impact on patient's quality of life. So let's take a step back, what is the degenerative cervical spinal disease. So this is part due to normal aging but also their lifestyle factors and we also know that some of the anatomical changes that happened with milo apathy. They kind of propagate and bring more the generation to uh to the to the spine. And like with most spinal pathology they can present with the cervical spinal disease can present with three main symptoms, axle pain, ridiculous apathy and milo apathy. We don't really know exactly what's the prevalence and what is the relationship. Because there are many, many challenges in actually quantifying the epidemiology of these diseases. They are not always present. They might fluctuate over time. And also for milo apathy as we will see a bit later, It's not really clear what should be the diagnostic criteria for milo apathy. So a few things about the degenerative spine disease. Again, one of the first things that happened, we believe is the generation of uh of the disc that brings them several changes that lead to stenosis and also instability and about a mile apathy. We believe that it starts with the compression or the formation of the spinal cord that can be either continues being there all the time. And we usually call that a static or intermittent that and we call the dynamic. We saw in the previous example that that patient on on the flexion and extension. There was definitely a significant difference in the anterior posterior diameter of the spinal canal. So there is a dynamic component of spinal cord compression. Many of these cases. Another condition that can cause myopathy. And we used to consider as a separate entity, but now it falls within this degenerative circle. Myopathy spectrum is diversification of the posterior looks to the ligament and you see here justification, you can also see here justification. And the question that frequently comes up is how much stenosis is required in order to cause my low Kathy. And uh, I really like that study is not a new study, but I still think that it's probably the best evidence we have. And it's so that actually there's not like a very absolute cut off point. But what they found is that when the anterior posterior diameter of the canal is more than 40 millimeters, none of the patients can buy low Cathy when it was less than six millimeters, all of them had, and between 6 to 14, which is actually the usual anterior posterior diameter of the canal for for many people. Uh, it depends and there are many factors that we still don't know what will make a patient to develop by local versus another one who doesn't have and some of the factors we think that there might be. Uh, the increased range of motion, like again, the first example that we saw that that basically have hypermobility, inflection extent of the cervical spine and when we have a patient with a cervical myopathy or we suspect cervical telepathy. We do the standard clinical evaluation that we we take the history. We assess for any red flags for serious spinal conditions like weight loss or any any recent trauma, weight losses for for cancer or a recent trauma that messages traumatic etiology. We asked specifically about milo apathy symptoms and we'll see what this might be. And then we do the standard neurological exam. Uh, and it's very, very important to do a thorough motor strengthen exam and also to assess the gate. We believe that the gate is a very, especially the tandem gate examination is a very sensitive clinical finding for the the and here's a little bit more comprehensive table of the signs and symptoms of, of DcM. The ones that I would like to emphasize is the loss of manual dexterity. This is very common. And very early the disease, the patients usually described that they feel that their hands are clumsy, They cannot they cannot use their phone and cannot use the fork and knife what they're reading as well as they did before. And gait and balance is also very, very common in the very early sign in the course of the disease. But we need to remember that there is not like a single finding that will allow us to place the diagnosis. Usually it's a combination and there's active research right now that that we're doing to see if there is one symptom or sign that is more sensitive, more specific than the than the others. Here's a question that actually addresses the four main symptoms are very common symptoms. Milo Kathy. It's more targeted for primary care physicians to allow the early diagnosis of milo apathy. So these these are again the four main symptoms that we see or we hear very difficult for patients. They describe that they're dropping things, the balance might be off and they might feel weakness in the arms and dominance as well in the arms. And they found that if the answer is yes to three or more of these questions, then there's a very high sensitivity to pick up my little thing. And there are many clinical skills for for milo Kathy and you know what I mean, traumatic spinal cord injury, we all use in scale but that's not a very good scale for DCM because first of all it takes a lot of time required like specific training and it's not sensitive to pick up the subtle changes that these patients have in the early phase of the disease, where it might be just some dropping of things, some numbness, some of the device might be off, which although they might not sound as serious as, you know, the motor deficits of traumatic spinal cord injury patient. But for a highly functional individual, they can have a significant effect in their daily activities in their overall functional status as we saw with one of the studies. So also, you know what another challenge that the spinal cord, you know um control so many functions and it's very difficult to come up with a terribly sort clinical outcome so short to evaluate clinical outcome scale that will also be comprehensive. And these authors, they suggested that we should actually track more than one clinical outcome and like the M. D. O. A. And we'll see what these are. So the first my love of clinical scale was this by new rick. We don't really use it that often anymore, although it's a it's a simple but it's a simple outcome measure but it doesn't really capture all the granularity in the disease. Uh The most common scale is the modified joo a where basically we assess for different functions. One is the motor function of the upper extremities, motor function of the lower extremities, the century function of the other extremities. And we take also the bowl and the platter. We ask about the bowl and the platter Actually the bladder. So this is the most commonly performed the evaluation or the most commonly used clinical outcome scale. It goes from 0-18. Another is that the pain scale that we use because it's very commonly present in DCM patients. And then this is the neck disability index although it's not specific for melo apathy. But we also says that as with all cervical spinal cervical spine diseases. And it's a quality of life outcome measure that we also use very, very frequently. So the differential diagnosis of DCM is actually quite extensive and in cases where we we have a degree of stenosis but we are not convinced that this is the cause of the symptoms. We very commonly refer the patients to neurology. Because as you can see here this uh this list is already pretty extensive and it's not, it doesn't include all the all the different diseases that can mimic DCM. So in these cases we just refer the patient to to an expert to investigate further. If it were not convinced that the compression of the spinal cord is enough to cause the symptoms. In regards statements in World Cup, we get very frequently X rays we saw in that previous patient. We also added the flexion extension because it can reveal dynamic instability. We also get an M. R. I. Without contrast. And in some special cases where the patient has a lot of hardware, metal, hardware and there is a lot of metal magnetic artifact or if there is a country in the case for M. R. I, then we might get city Maya la graffiti and also when you were planning to do surgery were very difficult to get a cT scan to see the bony anatomy in greater detail. But again, when we're evaluating the findings, we should try to correlate them with the basic signals because the stenosis is actually, it can be very very prevalent. Doesn't mean that every basement stenosis will also have my love of it. And that's something we try to clarify with this with this publication where some disease like if you have inter cerebral hemorrhage you get the cities, can you see the Emirates? And then you can place the diagnosis that the basic has Emirates. But that doesn't apply for DCM because again as we said, there are patients that they might have stenosis without milo Kathy. And in this case is in the same cases we get the information to support the diagnosis that is already we already have the clinical suspicion that the patient has this disease. And it's also to rule out any any other any other conditions. So it's not so much to rule in the diagnosis but more to support and rule out any other conditions that might mimic the DCM. There are some ongoing research actually. They have found that DCM can cause changes in the brain and we know that very well from spinal cord injury that uh there is uh there are changes that happen in the brain both at the cortex at the cortical level but also the brainstem level or the economic level as as a response to the spinal cord injury. And also in addition to the regular M. R. I. S. We have some new modalities that we're still investigating if they can provide us with more information for for DCM in cars to the neuro physiological work up. It is very very helpful basically when we want to rule out other conditions like very from neuropathy. It's a very common scenario to have a patient with gait problems in the degree of stenosis. But they also have like a significant diabetes. So in these cases we don't know if we're dealing with diabetic neuropathy versus the cm. And in this instance is uh the nerve conduction we lost this. C. M. C. S. S. C. P. S can be can be very helpful. And also during the surgery we always monitor these patients with motor evoked potentials and some of the essential potentials to make sure that the surgical maneuvers don't cause any any additional Compression and additional and injured 2 to the spinal cord. And uh we're still we're still not clear about whether all of these modalities are two mortar the disease. The reason is that we don't have very specific changes in DCM. That will make the sociological work up more and more useful for mortar the disease or to quantify hispanic or dysfunction. But this is an area of active research and who might be this might change in the next years. So another thing that is um it's commonly we can we see that in the literature are the physical performance tests for the diagnosis TCM And there's this recent study that they saw that all these tests actually they perform well for detecting motion of the DcM but they are not very practical to administer them in in the you know in the office setting. And uh there might be an opportunity for further research to see if one is better than the other. So probably we can do that or probably refer the patient to physical therapy for a more thorough evaluation of this uh of this test. And uh you know, this is an can be can be helpful but uh there's some people who argue that this is kind of outdated way to assess the physical performance of the patients. Now, we have all the wearable technologies like you know, to have the watches that can monitor many physiological parameters and they do that continuously. So probably in the near future might have applications through the horrible technologies that will allow us a little bit better the physical performance of these patients. And also there are some people who claim that computer vision may have an application where instead of fast trying to quantify for example, how many seconds it took for the patient to do the nine hole back test, then a computer vision might be able to assess if there's any tremor, if there's any inaccuracies in the patient use, you know, trying to perform the test and do that more easily and more objectively than any kind of evaluation by by human um by human. So there are definitely opportunities for further research in that field. And uh there is uh back in 2013, there was a study that so that there is actually a significant delay from the initiation of symptoms to the diagnosis of Milo Cathy. And this has to do again with the fact that in my present with subtle findings and initially they might, the primary care physician might attribute these changes to Normal aging or they might they might not take the complaints very seriously because initially they're they're very sample. And uh, you know, several years later, actually, there was not much progress in that other study. The patients reported that there was a delay 22 years between all set of symptoms and uh and getting the diagnosis and to make things even worse. There was a recent study that they were basically claiming that this disease is not only there might be a delay diagnosing diagnosing the disease, but there might be a significant other diagnosis or other recognition of the disease. So one of the limitations is that we don't have very robust diagnostic criteria about what what constitutes milo apathy and when we can safely place the diagnosis. So, uh I'll show you a few, a few things from the research that we're doing right now. So we're trying to review the literature and see how Authors and clinical studies that have defined by low empathy and how how they were able to place the diagnosis. And uh you know, we we consider that that could be like a proxy for coming up with some objective diagnostic criteria. And uh we we did a literature search but we came up with like 1600 different studies. So it was it was basically impossible to analyze that let's say manual or was very very you know laborious to do that. And we consider several approaches on how we can analyze the data from all these studies. And uh we we we realize that these three options can be very time consuming. So we explore a bit better whether the necklace of NLP can help us with that. So what is NLP NLP a branch of artificial intelligence and you can do many many things with NLP but I will focus on topic modeling and text summarization. So what what is topic modeling? So will you give you give a text to to the algorithm to the to the software And the software tries to detect either any patterns or any topics that emerged from from from the text and can do that in several different documents. And then comes comes up with a probability of whether a topic is present in a specific area of the text. So just to give an example we we fed the algorithm with all the data from this literature review. And then uh the algorithm came up with some word clouds like that and these were the topics that the Calgary detected in in the text. That we we we found the algorithm and then this is up to the experts in the field to try to make sense of what these words might mean. And uh we gave all the world class to a group of experts and we we agree that this is more like more likely referring to a motor dysfunction. So probably one of the criteria that we need to use for the diagnosis dcM is that there must be a motor dysfunction and there are a couple of other models. Again this has not been published yet and we're still working on it. So these are not the final results. But I just want to give you an idea of how that process goes and this is another another world cloud that came up and it contains very diverse terms like severity progression and we had trouble you know understanding why what this might mean and uh again because there was so diverse all the words here, we couldn't come up with like a unifying thing thing that will kind of bring all this together but then we realized that this might be some modifying or as we call reinforcing factors that in some questionable cases of milo path E that might make us link towards the diagnosis TCM for example if there is a progression of of the of the findings, if there is an instability, if there is any intermediary signal then it is more likely to be milo apathy versus not being my local thing. And another technique that we use is the summarization and this is actually you can have multiple applications in medicine I believe especially now that the medical medical literature has been growing so fast and it's very difficult to catch up with all the all the new publications that come up and all the new generals that come up I would say every day. So the text summarization provides like a concise summary and it gives us the important features from from the text. So we don't have to read the whole text ourselves but just get the important points from from the algorithm. And there are two ways to do that. Actually three ways to do that. One is the extractive fashion where the algorithm picks up some sentences or some words that considered very very important and considers that these sentences convey the important aspects of of of the text. And then there's the obstructive fashion where the sentences don't necessarily preexisting the text. But it's a way that the algorithm can summarize the data and present, present the data to us. And then there are several ways to combine the two techniques. So let me show you how that looks. And so these are two summaries that came up with the obstructive summarization and actually it doesn't doesn't look very bad and as you can see here although this is an automated process but there are some we call them hyper parameters, some instructions that we give to the algorithm and actually you can modify these hyper parameters to a significant degree and get different results. And uh this is still kind of an art meaning that there are no very specific rules on how you should modify or how you should, let's say fine tune this um this hyper parameters and how you can get like a better summary of uh of the text. But for example, here we we had a more lenient uh length penalty, meaning that the algorithm was coming up with a longer text, You had a smaller length penalty. And the algorithm came up with a with a shorter text. And here's an example of the extractive summarization followed by abstracting similar summarization. And uh this is again a way that the growth can help us summarize the data from multiple publications. And although, you know, we're still in the early phases of this new technology and they're still, you know, not performing optimally, but the way they are growing and it's really exponential. In every, every few months we have a new model, we have a new significant progress in the field. And uh I believe that not not not only me, but many people believe that it will be very useful in the near future. And I always like to to solve that graph here. It's about growing a business, but also applies for anything that grows exponentially. So our minds are used to think about linear growth and they're not so much used and think about exponential growth. So this is the new technologies initially they grow exponentially and there's always like a lag in the initial phases. And uh we explore them, we're not really impressed by them and then we kind of dismiss them. But these technologies continue to grow to grow. There is like this this point that they really then start to be much, much better than we expected and they start to impress us. So with NLP actually, I think we're at this point, if not beyond that point already. So let's go back to the global theme how how we treat it. So there was some guidelines published a few years ago and this is the longer version of the guidelines and I don't really read them. But this is the source version that basically we we do surgery, we offer surgery and we consider conservative treatment only. The signals are very mild and they're not progressing and if they're like significant comorbidities or the vision is of advanced AIDS. And the reason is that my local is a progressive disease. And also the outcome is related to the symptom duration. So basically comes to us and has symptoms for like six months, has a better sense of improving after surgery versus somebody versus delaying the surgeon offering the surgery a few years down the road. And uh you know, another thing that usually comes up is is there any role for non operative treatment. And this literature review again from a few years ago identified some shortcomings of the non operative treatment for for DCM first of all in the literature, they don't really define very well what is the non operative care? It includes very different modalities like traction bracing. And even when they discover these modalities that the details of the treatment are not very well very well defined. So other people define attraction as several hours per day, others several just a couple of times per week. And so it's it's unclear so there is not some kind of standardization allows to to draw some kind of uh conclusions. And also in terms of the of the medication. Some there are many publications that report, there was some kind of medication therapy but this is not well defined also. They have done the the non operative treatment in patients regardless of their uh of the severity of the DCM and we now know that for severe and moderate um severity disease then surgeries is a better option. So there's several limitations from some of the literature and there might be some actually research opportunities for the non operative TCM treatment. And I think that there's been more focus of uh of offering uh non operative care in mild cases. And we need more clinical studies specifically for mild cases of DCM also in regards to the postoperative care. This is not really standardized and I think that there is room for developing standardized protocols for DCM patients after the surgery and uh in regards to what might constitute a structure program, we we think that strengthens the neck muscles is very, very important and probably isometric exercise work better because they can offer the muscles strengthen benefit without placing too much stress on the of the musculoskeletal system or on the skeletal system. Actually. Then the spine posture we think is also very, very important work economics, targeted spine interventions can help with the pain that these patients might have and can facilitate a more effective physical therapy. And there's some early evidence that these patients should avoid excessive flexion or extension, but the modern reflection should be safe. So probably if we kind of standardize these instructions to or this type of treatments in mild cases, we might be able to find something interesting in regards to the surgical options. There are several surgical options. We usually divide them in anterior posterior combined approaches and also divide them in whether we're doing a fusion where we lock the bones together, whether we preserve the motion with an instrumented operation, whether we're doing all the compression or hybrid approaches, I'll show you a few examples. So, in regards to selecting uh anterior versus posterior approach, there are many factors that come into play either as multilevel stenosis usually go from the back if there is anterior compressive pathology which will go from the front. But remember that if we do a posterior decompression of the spinal cord kind of sits back. So in this case although there was this disc herniation compressing the spinal cord. And here we did the laminate to me. You see that the spinal kind of sifted more posterior early and although the disc is still there but it doesn't have any kind of compressive effect to the spinal cord. In regards to interior pathology, there are two main options. One is to do the fusion where we are removing the disc, placing a some kind of graft over there. Here is a photograph and we place screws and placed local bones together. Eventually we want these two bones to fuse together and become a single bone. In this case over here we remove the disk and we place an artificial disk. And although it sounds like a much better option actually might be a much better option. In many cases there are some limitations of the technique. You cannot use it. In every case there are some contraindications and also we're lacking some kind of uh more long term data about whether these devices are still functioning 20 years down the road. Well with a C. D. E. F. Remains the gold starter. You do the fusion if the bombs fused together, you don't have to worry ever again about that. That level of the spine. I would like to show your video now Just to give you a visual of how an operation like that is being done. So this is a case of 58 year old lady with the right arm with the arm weakness. You see that she has a significant we go back significant disc herniation at 56. And actual business herniation is very very classified. It's more like what we call austin find this complex. You see it's more born here and here's the approach just to orient you the head to the left, the feet towards the right, the midline is over here and over here we're doing a dissection and we're gonna dissect between the corroded artery and between the esophagus and trachea. So this is the plane that we have developed and we're already on the spine over there and we're developing the spine with this we call them peanuts. And also we use seizures to cut through the pre vertebral fascia. And here is the spine again and here we use the quarter to expose the bone and to elevate the longest colli muscle. Just to give you a few anatomy here is the longest colli muscle and and the anterior lateral aspect of it is the sympathetic same so soon injured that area because then we can give the patient a horner's syndrome. The corroded arteries here which we also have to be very careful about for obvious reasons they suffered a little bit more immediately and in the spine a little bit more deep. Around here is the vertebral artery that we also need to be be aware of its location. So many many important structures in a very very close to where we're working here, replacing the self retaining retractors. Here's the spine after the colorization. This is a pin that we put on the bone and that that will allow us to distract the disk space and open it up. And there are several advantages with opening up. It makes it this kept um easier and help us correct any any cathartic deformity that might be present over there. So you see here we place the knife to start the disk ectomy. You see that these materials like you know this calculus are going to remove a little bit more soft material and we use a combination for instruments to perform the mastectomy here we use a high speed drill bit to drill the posterior hasta fines. And over here we're very close to the spinal cord this way use that instrument to confirm whether we have removed all the bone or whether we need to remove more bone and there's still bone present there. So we're gonna continue drilling to make sure we remove all the bone and what is like one millimeter deep to us is the spinal cord. So this is where we're working and this is the drill. This is where the tip of the drill is and this is where the spinal cord is. Here. Some different use of where the instrument is and how close the spinal cord is to where we're working. So that's why we go very very closely. You see here there's a bony fragment that we're trying to retrieve and remove it but doesn't want to come out. So at this point we decided to work on the opposite side. And uh this here is the posterior longitudinal ligament. And uh you'll start seeing that we remove that ligament. You start seeing this glossy wide area. This is the dura. So this literally, you know that the spinal cord is right over there. So we need to be very very careful not to apply any additional pressure to to the spinal cord. And here now we go about after this residual piece of bone, the final were able to to retrieve it. And here we're completing the decompression. I want to see the the europe were very well decompressed. And here we use the size as a metallic instrument. That will help us choose the right size of the graph. And here is the L. A. Graph. So basically is born from a donor that is cutting in a state that will fit in that space. We're moving the beans. They will put some bone walks on the on the bone to get homeostasis. And over here we're working on the on the next level and after we're done, I didn't show you the other level. It was basically the same thing. We're going with some monster fights that will last place the plate and defeated a little bit better on the front surface of the of the spine. So here we're opening the holes for the screws here we're looking they have a locking mechanism that we activate here basically rotate that to lock them to prevent the screws from kicking out and these are the X rays after the surgery. Again. This is uh it was an A. C. D. F. Which is the most commonly done operation, One of the most commonly done operations for my lower body. Another person we frequent frequently do is uh posterior. Another approach actually is the posterior approach and there are two main options for that is the lamb in a plastic versus the laminate to me infusion. And you can see the difference here. Here is the vertebra before the surgery. And in the laminate to me we have removed the lamb in on but because you have very we have very important muscles attached to the spanish process. If we just do the laminate to me, then there's a very high risk for developing thai forces after the surgery. So that's why we need to put the instrumentation, the roads and the and the screws to lock the bones together and fuse them together in the lambda plastic. We weaken the bone over here. You see there's a trap that we made here and then we lift the bone up and place a plate to keep it up and we give a much more space for the spinal cord which is in this area. But we preserve all the important structures, all the all the important body structure for the stability of the spine. So in that case we don't need to fuse the spine. Again it's a very it's a beautiful operation but not every patient is a candidate for for laminar. Plus there's a specific contraindications mainly there is instability the spine either significant forces or significant neck pain. And actually we we have developed like a modification to the to the technique because what we realize is that when you only do the The λ plastic because the spinal cord kind of six posterior early there were some cases that this panel was getting kicked by the heads of the bone over here. So we felt that it's very very important when you do that operation to trim off the bone at the C. Two and C. Seven basically the cranial and caudal end of the operation. And our experience with this uh modification is actually very very good. I mean even patients with significant pain did better after the surgery. There was significant reduction in the actual neck pain but also significant neurological improvement in these patients. And again this technique seems to be working very well in our place in population. There's some hybrid constructs where we might choose to do both aluminum plastic and the fusion. This is something we've done a couple of times we were still trying to figure out what is its role you know in our armamentarium. And you know in our list of surgical options. So there's still an active of a feel of active research. Now I'd like to say a few things about the spine alignment. So we know that the spines will be aligned meaning that the bones will be probably one over the other and there will be no significant forces or corona plane imbalance. Because then the muscles of the spine need to work harder to maintain that alignment. So this is usually called con of economy. And we have very well established criteria for lumber spine. And recently we started to realize that the same criteria or similar criteria can be applied for the cervical spine. And here we see the most some of the most commonly used. I would like to just point out to the cervical sized vertical axis. So basically is the distance between the C. To the C. Seven. If we draw a plumb line from C. Two so the higher the distances means that the base has more flexion of of the overall of the spine. Market forces or so there is more work for the extensive muscles of the spine to keep the head up. So this is not optimal in patients with uh C. S. C. S. V. A. More than four centimeters. They usually have much higher pain and not as good quality of life. So one of the goals that we have in surgeries is to restore the normal low doses and and give us much uh has much improvement in the spinal alignment parameters. So I would like to see another field of active research that we do. So this is how we position the patient during the surgery prone position. And you see that there is a horizontal traction here. So we have applied the garden wellstone's you see here that these are things that get attached to the skull and through these talks will apply the horizontal traction. But during the surgery we have the option of saying that the vector of attraction towards the ceiling to induce more lower doses or to elevate this support for the face again to give more lower doses to the cervical spine. So for example here I'd like to show you two inter operative x rays. So this is how the spine looked by having only the horizontal vector of traction. And then when we change to both this oblique traction and also elevated the head, you see that we've got a better alignment, better lord dose of the cervical spine. So we're actually actively trying to figure out which technique works, works the best to combine the elevation and the public traction. So we use one of the two. And so this is what we're actively looking um And this is a pre op and post op you see how we gave more lord doses to the to the spine. And here here's the pre op and post op. M. R. I. Another thing that we're actually looking at is what is the quality of life for patients who undergo long posterior infusions. Because we know that 50% of the range of motion of spine comes below from below the sea to the other 50% comes between the head and the C. Two. So if you're losing 50% of the range of motion is associated with significant it should be associated with significant reduction in quality of life. But Our impression is that this residual 50% is more than enough for the daily activities that we very rarely use 100% of the range of motion of neck. But again this is something we are actually looking at with our patients to see if this is this is the case or just a false impression that we have Now in terms of surgical prognosis there are several publications that report that uh surgery can have a very good outcome. And they have uh they have established that at different time points. As you can see over here the overall effect is definitely positive towards towards improvement. And this is for the J. O. A. So this is for the neurological outcome. This is for the overall neck disability. And you can see that this also significantly improved multiple time points. And uh you know these previous publications were just describing you know what is what is the overall outcome. So there can be some efforts in trying to quantifying or trying to prognosticate a little bit better. So there's a more recent publication where they're trying to provide some uneasy to implement prognostic scale about who will respond or who will not respond to surgery for 40cm and identifying that the pre operative forces the number of levels that there is compression of the spinal cord from both anterior and posterior and also the length of the spinal cord changes. They call them the intermediary religion. So they found that these three factors are very important for predicting what is the outcome from the same surgery, but the same surgery is not risk free. There are several complications that can happen. Some of them they're they're rare, but some of them are serious, but hopefully thankfully they're there, for example, spinal cord injury injured the or the vertebral artery injury to the esophagus. Some others are rare, but they're more easily managed. Or they might be self limiting. Like if there is uh injured with the current law, original nerve from anterior process because we're working very close to that nerve or as we, as we discussed, you know, there might be Horner's syndrome, if we injured the longest school line muscle, but most of these are or some of them can be self limited. For example, the original nerve injury, most of the times it's a neural protection. So basically it was just from the retraction of the nerve and it gets better after a few weeks. Very rarely. It is due to a transaction of the nerve that is associated with a permanent permanent deficit. But what we deal with most commonly is um if we do a fusion that the bonds might not heal together, might not fuse together. It was the infusion. We might see additional disease that there is above and below. There's that refused and another common uh not common but a complication that we see from Time times the C. Five policy. It's basically it's weakness to the deltoids and biceps muscle after after surgery. So here's some publications that they try to come up with a percentage of uh what is the accumulative incidence of these complications. But all these studies, you know, they provide us with an overall view or some overall description of what the outcome will be or what the complications might be. But they're not very specific for, they're not individualized. So I'd like to show you an area of active research that we do. And we're using the data from the National surgical quality improvement program of the American College of Surgeons. So this is probably this is probably the biggest database that we have for surgeries. And we have applied some newer type of analysis basically machine learning algorithms And they have several advantages over the more traditional. It's a logistic regression or linear regression. First of all their overall methodology that you what you do in these cases you take 100%, you know, all the data, 100% of them and then you split them into train so you split in 70% for for training the algorithm And then you keep the 30% of the data that al-Gore never never sees. And you come up with a model and then you you take that model with the test data and see how well that model performs. So it's a very it's a clever way to do like an internal validation of the model and also these albums. They're they're very good because they can detect nonlinear relationships. So for logistic regression or in immigration, there is this assumption that an increasing one value leads to an increase in another value the outcome. Or, you know, an increase in one of the predicting features has a linear relationship with one of the outcome measures. But this is not always the case. And uh these outcomes for example, the exit boost gotta boost these newer machine learning outcomes. Can actually detect nonlinear relationships and the overall they provide higher prognostic and predictive accuracy than logistic regression. And they also allow for more accurate predictions at the individual level. So also you hear how one of our websites look for spinal tumors. But as I said, we're actually developing a very similar run for cervical spine surgeries. So you go here and you insert the AIDS, the sex, you know, all these parameters that They can have a predictive value. And then the algorithm can give you a specific prediction for that for that individual. So it can show you that there's an 8% chance for a prolonged length of state verse 20% for a not prolonged length of state. And that's specific for that basis, not just for the various population. General. And also it allows you to assess what is the overall feature importance both at the individual level. So let me go back here. So this is at the individual level. So the outcome sources that these feature values are very very important to predict the long length of state for that specific patient. But I can give you also uh some estimations about what are the features that are important for the overall basic population. If you if you wanted to do some population wide interventions then this is a more helpful feature important scale. So for example here it shows that AIDS uh this specific cpt code uh and for example if the americans uh society of anesthesiology classes still. So all these values, probably they are associated with higher they have a higher importance for the patient population. So I was talk here to a lot of time for for questions. Um thank you for your attention