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Atlas Innovations: ZEISS QEVO: The Microinspection Tool

Juan Carlos Fernandez-Miranda, Amir Dehdashti, Walavan Sivakumar

June 28, 2021

Transcript

- Colleagues and friends. Thank you for joining us for another session of the Atlas innovations. Today, we'll be talking about Qevo from Zeiss Meditec. Qevo is a micro inspection tool that's been very helpful in terms of how visualizing the operative blind spots. Our guests today, who will be talking about the utilization of this useful tool. Are Dr. Amir Dehdashti from Northwell Health, as well as Dr. Wally Sivakumar from Pacific Neuroscience Institute. Both of them are very accomplished micro surgeons, and I'm very excited to introduce them, and learn how to use this useful tool. One of the most important shortcomings of the intraoperative microscope is the fact that we are unable to pass around a straight light of the mind, a straight light of the scope to be able to see around the corners. So, having a device that can actually provide practical visualization without necessarily bringing the endoscope, which can be as fair amount of work and time to get everything going, would be they're useful. Before we go to our speakers, I'd like to introduce Qevo very briefly, that extends boundaries of neurosurgical visualization. These are disclosures that these opinions are ours. I also want to briefly introduce the robotic visualization system by KINEVO that's been quite effective, but it's not the focus of our discussion today. So the robotic visualization is obviously Surgeon-Controlled. It has Digital Hybrid Visualization, and the Qevo is another tool in terms of providing a 45 degree micro inspection tool, like a 45 degree endoscope, to be able to effectively see around the corners, very practically, and we can bring it into the operative field and well-integrated through the microscope. This is a picture of the device. And, as you can see, you can explore areas that are critical and not easily seen through the straight light of the scope. It's cranked design supports a new degree of safety for insertion into the operative field. And it's really easy to be able to hold it while you use your other hand to perform the operation. You can easily toggle between views between the microscope and endoscope, or the Qevo, and that's something significantly better than bringing an endoscope that can be quite impractical and time consuming. And also this is autoclaveable and can be reused easily and therefore can save some further costs. So again, I think the principle is to have a 45 degree inspection tool endoscope like device that you can bring in quickly when you need it on the fly, rather than suddenly remember in surgery, or find out that you need one, by the time they roll in the endoscope, take out the microscope, make all those accommodations that can be quite challenging. And then switching between the endoscope, the microscope can even be more challenging. So this device really has been an incredible tool to be able to provide a fast highway for us to see around the blind corners in the operative field. So now I like to ask Dr. Fernandez Miranda at Stanford University. This is really a very innovative tool. Tele surgery or tele-dissection where he's actually right now at Stanford University, I'm in Indianapolis. And he's going to show us in his lab, how use his Qevo on cadavers in terms of seeing things around the corners. Well, Carlos, thank you for joining us and let's go ahead and go to Stanford University in Palo Alto. Thank you.

- Thanks, Aaron, it's good to be with you again. And as you mentioned, we are here in our Middle Train Center in Stanford university. I'm here with Max by my side, who is one of our fellows, doing phenomenal work. And we're going to do some nice dissections on how to apply this new technology, the Qevo from the size of microscope. As you know, the Qevo you can see here is a device that isn't, it's like an endoscope, but it's actually a visualization tool or an inspection tool that compliments the microscope really well. And we wanna show you how we do this in these dissections, but how can you apply this into surgery. It's a very simple device, that you see, it has no bottoms on it, at all. Everything is controlled from the control panel in the microscope. You can rotate the view. Is this an angle endoscope by definition. Is a 45 degree angle scope by definition. So, it gives you this view that is angled beyond the reach of the microscope. So, it compliments the microscope. So, let's go on and start looking at the, the case example. This is a super cerebellar approach, which actually we're going to be transtentorial on the patient's left side. I wanna look first with a microscope, a panoramic view. Then we're going to go with the Qevo device to augment our visualization. So Max, go ahead. So as, we start seeing the... you'll see the super cerebellar route. We're using now the microscope in the exo scope function. We are at 600 millimeters, 626, actually, of distance from the focus. And this is the POV visualization we can get. Guido, can you give us the close-up view? That we used before? So, Guido our technician can actually now... This is the more panoramic view, and then let's go to number two. And then we chose these views from before. So the microscope with his robotic function can directly zoom in, and give us this visualization on the supracerebellar pineal region. So, Max is showing us the pineal gland, very nicely. Max you can always start exactly showing, showing this around, and you see the cerebellar, encephalic fixture, and he's gonna move the tentorium beautifully. So you can see the medial temporal lobe, as you know, this approach has been used to access the medial temporal lobe for, you know, lesion at cavernomas or tumors Beautiful view there. You can see the ambient cistern or you know, how the quadrigeminal cistern becomes the ambient cistern more anteriorly. So, you have beautiful visuals with the microscope. You can see the quadrigeminal plate, the superior colliculus, you can see the basal vein. You can see the Corpus callosum superiorly, you know, the vein of a gallein. And yeah,

- [MAX] The third ventricle

- [Dr, Fernandez] The third ventricle you have the roof of the third ventricle towards the velum interpositum. Exactly, that is probably the internal cerebral veins, right? Going in, or coming from the roof of the ventricles. But this is all the microscope can give you because it doesn't have this lateral angle view, right. You're gonna go, Max with a microscope, go in, now if you agree. And so, as you were using the microscope, we were using as we said, the exo scopic function before, Max will from the top. Now we're gonna go with the microscope as we typically use it, right. With the viewer. And we're going to focus in that area. We're not trying to maximize our view in this area. There you go. Similarly, Max is approaching this, seeing the collicular plate and a beautiful view of both superior and inferior colliculi right there. And to maybe Max, why don't you try for example, to go into the third ventricle, see what we can see, going into the third ventricle with this approach.

- [Max] We push the pineal

- [Dr. Fernandez] Yeah, so he's doing the para pineal approach or supra pineal approach. You went to the supra pineal recess to enter the third ventricle. And perhaps you can, you want to zoom to that area, and, zoom there. And Guido, if you wanna show us the device, how you, maybe angle a little bit, one way or the other, you see at this had other role or the function that is nice. So we can maximize our view around that focal point. And this is the microscope moving on its own. And that's the beauty of it. You can see the choroid plexus on the roof of the third ventricle, right. So perhaps now it's time to start adding the Qevo device. Let's see. So, here is our Qevo. And, here you go ahead. So we're gonna access with Qevo device now. And the good thing about these device is that it doesn't dissolve your workflow. You are at the same time working with the microscope and you bring your inspection device to see beyond what the microscope can show you. You can keep your microscopy view on that upper corner. And then we ended up with a Qevo and are gonna look into that quadrigeminal region. Now this, as a surgeon, you are either looking to the viewers of the microscope, because that can be fed into the view of the microscope, or you're looking to a monitor. That is very nice of view Max. And then, now, as an endoscope this becomes sometimes contaminated. So you need to bring it out, irrigate it, wipe it, etcetera, if needed or as needed. There you go, Max that's very nice. So you can see, you can track all the paracerebellar or precentral vein and go around it. You saw how Max nicely pursuit of that vein that often is sacrificed in surgery, in the midline. And from there, let's try to get into the, into the, third ventricle parapineal as you were doing before, right. I can maybe help you move in this vein a little bit.

- [Max] Mjmm

- [Dr. Fernandez] You see that's the thalamus, right there, the pulvinar. That's our velum interpositum. Again, that's always a problem with any endoscope device that it gets contaminated, you need to bring it in and out. There you go. Now the device is looking up. As you see here, I'm going to move this pineal. I'm gonna get a unique view. Look at the view between the Corpus callosum, and the velum interpositum, the internal cerebral veins coming from the roof of the third ventricle. So, that's the kind of view that you will not be getting with the microscope by the Qevo device really assist you on getting better view. Also, you got a tentorial meningioma here, or far tentorial meningioma. you can see this far tentorial junction really well superiorly, which you cannot see well... with the microscope. Is an area where you need to decide how much do you need to remove and what you leave behind. This is the area of the junction of the veins, right there. That's great views. And, maybe now, Max have seen as, showing us very nicely, the medial temporal lobe, on these left side, and, we're going to have to fold the medial temporal lobe along the incisura and ambient cistern In this direction right there. That is very good Max. So we see Corpus callosum up here, medial temporal lobe here. So this whole direction into the, ambient cistern here.

- Yes, this look good Juan Carlos, would you mind also showing us to the ventricles, maybe another example for us, since the time is limited, show us how you can work much better and have visualization within the ventricle, please.

- [Dr. Fernandez] Yes, absolutely. So, in this device, let us show as CP angle perhaps first, right? You went out with CP angle in this specimen Max?

- [Max] Yeah.

- And then we move into the ventricle. So now in this example, we're looking at the... Look at the fourth ventricle and the view you're getting there A beautiful view of the roof of the fourth ventricle. With a Qevo device, you can see the dentate nucleus. That's a great view. Nearly a bit angle has been cut, and then let's go to the inter acoustic canal. There you go. And now we can see along the P2 surface much more than we would see with the microscope because of the angle nature of this inspection tool. Very nice. Now we're looking at the three pontine region, you know, the area where you access to a transcranial endonasal approach or through, you know, retrosigmoid, presigmoid approach, depending. You can see the basilar, the whole source of the clivus and we're using the Qevo inspection tool to see better. You can see the sixth nerve and we are working below the sixth nerve. Okay. So I don't know we are looking at the...

- [Max] That's the one?

- [Dr. Fernandez] That is the one. Yes.

- [Max] Okay.

- [Dr. Fernandez] So now, we're not looking at the skull base from a lateral approach. Imagine a retrosigmoid, or a combined transpetrosal approach, with a lot of dissection. You can see the, the view of the internal acoustic canal, there's seven and eight nerve, going into the... Into the canal. And, you know, Max is there sitting in front of it, like if you're within a transpetrosal approach, and, Guido, you can give us a closer view, The next one please. We're gonna look into the pre punting region, as we will, let's say three in a pre tentorial angioma or epidermoid in the prepontanious space. So, the limited, the V.... the microscope, often provides limited visualization in this space because it's very narrow, and it becomes very medial. And here we're looking at, you know, the sixth nerve, that clival region, you can see the inferior petrosal sinus. The vessel are already inferiorly, and working above the seventh and eight complex. And that is a view we can get with a microscope. We're going to now, put the Qevo device and augment our visualization. So, there you go. Guido, you please change to the Qevo device, There you go. So, now we have our Qevo device, we're looking at a lower cranial nerve, right? So let's see Max, if you can look above seventh and eight.

- [Max] Seven, eight, above.

- [Dr. Fernandez] Aja.

- [Max] To reach the prepontine area.

- [Dr. Fernandez] So we're looking at the prepontine area, and we can see... Can almost see all the way to the contralateral side. So imagine you're doing an epidermal tumor, and you think you are limits and tumor behind. You can not see it. You can use this inspection tool, to confirm that you have, or not, tumor left and in cases like epidermoses, relatively simple to use a section and remove more of this tumor. And these you can do with visualization. Is that the contralateral sixth nerve under?

- [Max] Yes, yes it sixth.

- [Dr. Fernandez] That's the contralateral sixth nerve, Entering the contralateral canal, which is, almost an impossible view to get together with a microscope. And its really good. A good transpetrosal approach, but not with a retrosigmoid, to se the contralateral sixth nerve, but sometimes epidermal is extended, right?

- [Max] Yes it is.

- [Dr. Fernandez] Good. That's a very nice view. Okay. Let's get, let's get another example on the ventricle, right? So, now we're going to look into the... Give us first view with a microscope. So, so now we're going to simulate. Yeah. See if you could, Guido, you can focus for us in there. Again, using the robotic features of the microscope. We're gonna do a simulate, a contralateral interhemispheric approach. Precuneus into a hemispheric approach, contralateral to the atrium, to the contralateral atrium. Okay? So, we're working with a microscope first. And, you can see the view of the lateral wall of the atrium. And we had a bit out of focus. So let me focus this a little bit. There you go. That's much better focus. In fact, let me move this a little bit, because we want to be centered, right... Oops. Right there. So you can focus there Guido, So we make sure that we are completely focus there. So see how the corpus callosum is in front of us. Also, what is called the isthmus the cingulum. Is been gently detected forward, with open yes behind it, looking into the atrium. So, now we're going to assume into that area, and this is as much as you can see with the, with the microscope. Maybe, if we move it a little bit in this direction. We can gain more visualization of the atrium right there, but, that's pretty much what we get, all is. We start getting more white matter of the middle of the ventricle. So, now we're going to use the Qevo device and get into this area. And naturally, you know, endoscopes and visualization tools like the Qevo, work wonderfully in cavities like the ventricles. So, here we can start seeing, much more than what we've seeing before. You can see normally the lateral wall, by we start seeing some of the roof of the atrium, and more importantly, all the way until we see the thalamus. And we see the choroidal fissure. I can remember them through the wall of the atrium, formed by the thalamus, posterior part of the pulvinar the ventricular side of the pulvinar, and the choroidal fissure that you see there. And the fornix will be also in the front. And they fissure in between both. And we can even see the floor of the atrium, going towards the temporal horn, he post occipital simple horn. And we can maybe look even anterior and to see from the atrium all the way to the frontal horn on the body of the, of the ventricle, you see that blue is, is what do call these, the clonus, of the other choroid plexus.

- [Max] Mjmm.

- [Dr. Fernandez] It's a large choroid plexus. And you see the tremendous advantage of the Qevo, when working in this cavity, in this ventricular cavity.

- Okay. So, this is the view of the... Operating angles for the brain stem, as you can see, and let's go ahead and bring the Qevo in, and you can see the operating is holding the Qevo in a specific orientation. So, Max, if you can please bring the Qevo in at this stage, and you can see the handle is being held in a specific orientation, let's go to the Qevo angle, and now you can see the angle there, but we can control the angle of viewing through the Qevo, as you can see in the control panel and be able to align the orientation of the viewing very much with those of the microscope. So in this field, angles are aligned. And in addition, we can go ahead and adjust the light to be able to see more at the depth of the like operative angle. Guido, can you change the angles one more time? So people can appreciate the changing angles that they have control over. You can see if you change the angles until the viewing angle is aligned with a microscope without necessarily moving your hands and putting it in an uncomfortable position for the operator. Thank you. Great. Great. Juan Carlos, I want to thank you for making the time to do this, really a nice tool to see around the blind spots of surgery. Again, thank you, Max. Thank you, Juan Carlos. Incredible work you guys are doing in the lab, in the lab at Stanford University. So again, thank you.

- [Dr. Fernandez] Thank you Aaron.

- So, guys, again, thankful for having you today. Amir, let's go ahead and start with your talk. Thank you.

- Thank you very much, Aaron. And I would like to thank Taiz and Guido for giving me the opportunity to describe our experience with the use of Qevo micro inspection tool during microsurgery for brain, vascular and tumor surgery. I am an endoscopic skull base surgeon, so I think it's important to mention that, that the Qevo is a two dimensional visualization of the hidden area in the brain. And it's a little bit different from what you get with a 3D dimension. So it's important to have some degree of training, and experience with two dimensional work inside brain. And with this in mind, I would like to also to emphasize that as much as I'm advocating for minimally invasive surgery, including endoscopic skull-based surgery, including mini craniotomies for brain aneurysms or microvascular decompressions, I think, I have tried, and I think the concept of having an extremely small opening and using the inspection tools, including endoscopes, to improve the visualization is not necessarily helpful, because you need to have at least some degree of maneuverability of the instruments. So, just doing a small bare hole, or in large bare hole and going after a complex surgery, to me, it does not make sense. However, making it a little bit bigger opening, which is still would be a mini craniotomy, that will allow a very good microscopic visualization of the intracranial structures, even deep structures. And if need be, specifically for hidden areas, then bring down the Qevo micro inspection tool to look around the areas that are blind and they are not clearly visible with your mini craniotomy exposure. So, yes for minimally invasive exposure, but not too small, not bare hole or not an enlarge bare hole, because I think that's very important, because if we get into a complication would be very difficult to deal with it, if you have it very tiny opening. So, with this in mind, I would like to go to the indications where I think, the micro inspection tool, which is Qevo in the setting of sights microscope would be very helpful, For aneurysms, paraclinoid aneurysms, specifically, superior hypophyseal artery. Specifically, if there are small aneurysms and I'm going to give you and show you examples where these aneurysms almost not visible sometimes when the full exposure is done. Also to confirm the patency of perforators. Superior hypophyseal artery vessels are extremely important. I have heard many people say you do don't care about the SHA arteries. They are not that important. Sometimes you can get away with it, but we know that if you are an unlucky day, a sacrifice of one superior hypophyseal artery, can cause Kawaze ischemia and significant visual deficit. The same for anterior choroidal artery, vascular tip, and also PICA. PICA. Once, although the exposure can show all the perforators around the pike hole, once the clipping is done, you might not be able to clearly see the perforators in the blind spot. And that's where the inspection, additional inspection tool with Qevo will help. For tumors, I think there were three areas, specifically In the pineal region. Specifically, if the tumors there is extensive, the petrous apex after an approach such as Kawaze or anthopituisectomy, where the opening is relatively small, and you really need to look around the angle. And, if it's tubular schwannoma to look into the internal artery canal, when the tumor in that part is removed and you do not want to open the canal longer to not to reach the medianly or superior semicircular canal. And finally, I think for microvascular decompressions, I'll do... I do... I have not really felt that I have needed the endoscopic visualization for further visualization of cranial nerves, but I think for fifth and ninth to neurologia, that could be a helpful tool. Not for hemifacial spasm because, we really rely on the lateral spread responses for hemifacial spasm. So I don't think an endoscopic visualization would further help, however, for trigeminal and grocer pharyngeal neuralgia, I think that would be helpful. Now, I'm going to focus mainly on vascular surgery and I'm going to want to show one tumor case just to show you, how will we utilize Qevo during surgery. So the first video we will discuss the resection of an epidermoid cyst in the sitting position. This is a patient who presented with an extremely large quadrigeminal cistern epidermoid cyst. As you can see on the MRI, with obstructive hydrocephalus, we decided for a sitting position, and as you can see, that's a super cerebral or transtentorial approach. And these are different approaches we can get to this tumor. We decided for supracerebellar transtentorial and also the tentorium needs to be caught to get access to the more lateral and superior axis of the tumor. You can see here. This is the approach to the paramedian supracerebellar. Is a retractor less approach, and falls with the gravity, and we already get to the cyst. And the it's important to emphasize that the epidemic cyst removal has to be with removal of the cyst wall, just removing the contents of the cyst is not enough. And as you can see here, I'm separating the cyst wall from the brain structures. This is the edge of the tentorium that will be cut to allow the access to the superior extension of the tumor. And you can see here we get around the cyst, removing the content, and then separate the cyst wall from surrounding structures. This is after the tentorium is being cut. You can see the... cyst content is being separated. Here, you see the significant adherence of the cyst content to the tectum. And this is the back part of the temporal horn of the ventricle, which is opened. You can see CSF is coming out, which will confirm the lateral extension of the tumor. Now further separation of the cyst from the brain structures is being performed. And you can see here that posterior cerebral artery. This is the P3, P4 segment, extremely stuck and necessitates a very meticulous dissection. And at some point, we realize that the... cyst wall is really invested into the P3, P4 segment. However, we do the best possible to remove the cyst wall from the artery and at the end, only a tiny, very, very tiny remanent will be remained because it's really, as mentioned before, invested in the vessel wall. Now we have the micro inspection tool coming in, showing the... posterior aspect of the pulvinar, the tectum, the PCA, the vessel of inner Rosenthal. And we can see a little bit residual tumor. Here is where is important. Then we go back to the microscope and remove the cyst wall from the lateral aspect of thalamus. that was visible on the endoscope and then actually, what seemed to be gross total resection. Although there is a tiny remanent on the... MRI, that you can see extremely small, but we were happy with that. The patient's neurological exam significantly improved, he's ventriculostomy was removed. However, three years later, the patient had a recurrence from that tiny remanent. And we decided to go back with the same approach. And if you can go back to... as you can see the remanence of the tumor that grew back in the... right side of the quadrigeminal cistern, after discussion as tumor decided to go back and say this is a young patient, same approach. We can go to the video. So we are the same approach sitting position, opening up the cyst wall again. And you can see here the same thing, significantly adherence cyst wall to the structures around mainly the thalamus the tectum. Meticulous dissection is being performed. Again, the same vessel, the posterior cerebral artery, here, which you can see is, again very stuck to the tumor and the same way as before we will separate the cyst wall from... The... Vessel. And push through the aspect of the brainstem. You can see here, the vessel of inner Rosenthal separation of the cyst wall. Again, this is from the posterior aspect of the thalamus in Corpus callosum, display some of the Corpus callosum here, here to, Qevo is coming in to look at all the structures. You can see the vessel vein of Rosenthal here, the thalamus here. And, we can see that the resection is as completed it can be except for this tiny remanent, along the PCA. That is honestly, if I sacrifice this vessel with the intends to do a bypass on P3, P4, there was no other option. So I decided to still leave that tiny, tiny remnant. And otherwise there's a gross total resection beside that post-operative shows that tiny residual at the quadrigeminal cistern. The patient did fine after surgery. And real closely monitoring for recurrence. Obviously there is always a risk, but hopefully this time, despite... that tiny remanence, because it's completely coagulated, we the hope that, that will not recur. This is a patient with two aneurysms, PCOM and anterior choroidal artery. And this part here, you can see, this is the anterior choroidal artery, this is the PCOM aneurysm here, but we want to focus on the anterior choroidal artery aneurysm that is right there. And this doctor Prashan, my fellow, who had helped for preparation of all these videos. And he's doing the surgery here with me and, he only open the falciform ligament to release the pressure on optic nerve. You can see the choroidal artery perforators here. The aneurysm is here. So here we were going to clip this choroidal artery aneurysm we'll look with the... Qevo to see exactly where are the perforators. There's no other way to see these choroidal artery perforators in the back wall. Than with the micro inspection tool. So here, the aneurysm is being clipped, but with the endoscope, we will see that the aneurysm is not fully clipped. The perforators are okay, but the aneurysm is not fully clipped. Which necessitates repositioning of the clip, advancement of the clip, and eventually switching the clip to a longer clip. And you can see this is the Qevo going in here, to look at the... situation. You can see that the perforators is preserved here. This is the PCOM aneurysm that will be clipped later. And here you can see, in this location that the aneurysm is completely occluded. So this is one you can see this other perforator just behind a clip, which is also preserved. And ICG angiography confirms patency of group. So the Qevo is very important to confirm patency of choroidal artery, and complete occlusion of that small aneurysm, which is outside our field. And then we'll take care of the PCOM aneurysm without the need for Qevo here. In the next video, I would like to emphasize the importance of visualization of the perforator on the ACA. This is a patient with two aneurysm. One superior hypophyseal artery, and one... A1, lenticular striate aneurysm. Opening up the Sylvian fissure. And this is A1 aneurysm here. This is the carotid bifurcation. This is the lenticular striate artery here. And, we see the... I'm using a French technique here to... push the perforators with the surgicel. This is the aneurysm here, and you can see the back part of the aneurysm is not visible because it's completely on the dark side of the moon. So using a curved clip, pushing the perforator side, getting around this A1 aneurysm, a lenticular striate artery injury here can cause, significant hemiparesis. So the aneurysm was clipped here, and this is the Qevo going in and showing the perforators. You can see the perforators here, they're all open. And this is a clip, completely across the neck of the aneurysm. So that confirms that the lenticular striate aneurysm is taken care of. Now we will go for superior hypophyseal artery aneurysm. That is if you can advance just a little bit here, and in here, you can see the aneurysm is almost not visible. It's not a large aneurysm is hidden behind the optic nerve. We detect the falciform ligament and you can see here the Qevo is very important to show the exact location of the neck of the aneurysm. You can see here, this is the distal neck here. The proximal neck is just that to do a ring, and again here, I'm not going to show the part that is irrelevant to Qevo clinoidectomy or opening up the dual ring. But just going to show here that once a preparation is done, the fenestrated clip is going around the aneurysm, and the position of this clip with the 3D visualization that we have at this point, based on the Qevo. And there the aneurysm is. And the aneurysm clip is being positioned around the neck of the aneurysm and being pushed against this whole base to confirm complete occlusion of the aneurysm. And then Qevo will go back in, in the space within the choroidal artery and optic nerve. And that's here, the Qevo showing clip across the neck of the aneurysm and patency of those small superior artificial perforators. There's no way that one can visualize this without the micro inspection tool. Clipping of... ophthalmic artery in P1 aneurysm So this patient, if you can stop just on this slide for a second, this patient had prior subarachnoid hemorrhage with the right superior cerebral artery aneurysm. That I had clipped a few weeks or a couple months before. She has a left ophthalmic aneurysm. She has a left hypophyseal or clinoidal segment, which is not clear whether it's extra or intradural, and a left vessel or the P1 aneurysms. So here we can see this aneurysm. It's not clear whether it is intra or extradural this is clearly intradural and there is also a P1 aneurysm. Just after that, that we will see Vessel are to P1 aneurysm, if you can let the video continue. So here with the Qevo, we visualized the medial side of the choroidal artery and we confirm, the Qevo going in, and confirmed that there is no aneurysm intradural. That, well you can see this as a super beautiful view of the superior hypophyseal artery. This will do a ring and there is no aneurysm. So, that aneurysm that is in the clinoidal segment, technically is extradural. Doesn't need to be treated. However, this aneurysm, the ophthalmic artery here, has to be treated, but before getting to this aneurysm, we go to the posterior fossa. This is the carotid or oculomotor triangle. You can see the membrane here, and you can advance the video a little bit. This is the third nerve here, retractor list opening of the posterior fossa arachnoids. And here you can see, this is the thalamus perforate or coming from the P1, is a very narrow angle, and bit prior subarachnoid hemorrhage. There is some adherence of arachnoid. We identify the aneurysm neck here. If you can advance a little bit, you can see the carotid artery here. The carotid has to be retracted. This is the bilobed aneurysm. And a clip goes around. There is an important perforator just here that it was detected before that will be preserved. The clip we'll go around the neck of the aneurysm. You can see this is here, my suction, and this is my fellow resident, who retracting the carotid artery, medially to allow visualization of that important perforators. And here we need to add two clips on this, just as a booster is a mini clip I'm using, and you can see the PCA and perforators. You can advance a tiny a little bit here, to show the second clip going in as a booster. Here also, we can potentially use the perforators. Visualization with the inspection tool. I don't believe I used it in this particular situation here, because it was quite obvious based on... visualization at... surgery that the, the perforators a patent. And you can see the carotid artery, is a very narrow and hidden angle, but, we were able to take care of this aneurysm. Several clipping strategy was evaluated. You can see here, the choroidal has been resected. We can clearly see the proximal neck of the aneurysm here, which is perfectly ready for clip placement. This is my fellow here coming in with an appropriate clip that is laterally curved. Passing it parallel to the carotid artery. I like to clip this ophthalmic aneurysms in a way that they clip sit down and basically sits parallel to the lumen of the carotid artery. And here needs... two clips to... add a booster and completely accrued this aneurysm. Can advance a little bit more, but here is very important that we confirm with the Qevo that there is no aneurysm on the other side, because, first of all, that aneurysm doesn't need to be treated. And second, if there was an aneurysm and we go with the clipping of ophthalmic aneurysm, there is a risk of... rupturing the dome of the aneurysm, because it would be exactly on the opposite side of the ophthalmic aneurysm. And here via look with the Doppler. Which check patency of the parental artery, you can see here the ophthalmic artery that is patent. And this... in the second clip is being added as I mentioned, to confirm... the completeness of... closure of the aneurysm neck, and booster clips sometimes on this broad, these aneurysms are necessary, and this will... conclude the clipping of this patients, all intracranial aneurysms. Intraoperative angiography confirms patency of all parents vessels and, exclusion of all aneurysms. So I think main advantage of the Qevo is that it's easy to use. And there's no question that improves visualization. I think, at least in my practice, the most important aspect of Qevo is that it's confirming the understanding of the anatomy, shows the hidden angles and confirms the completeness of treatment. And the way I have used it has been mainly for confirmation or help to understand better, and then switch back to microscope. This switch, quick switch between endoscope and microscope is invaluable and, having used other type of endoscope before, having this inspection tool integrated into microscope, makes it so easy and so seamless, I don't think it was anything superior to that, at this point, for this particular purpose. I think Qevo is an essential tool for selected cases, is absolutely necessary for some, like some aneurysm that I showed and some tumors. And I think is valuable in many surgeries, including MVD. I'm not saying it's absolutely necessary for microvascular decompression, but I think it's valuable. And, these are tools that we have, whatever we can do to improve, our visualization or outcome after surgical treatment, that I think is a significant plus to our armamentarium. Now, I have to talk for very brief about the weakness. I think one major weakness is that is a two dimensional visualization. So if, for me, being an endoscopic skull base surgeon, that's not really an issue, but some people might have a problem with two dimensional visualization and work. The other thing is that I think the diameter of the endoscope is a little bit too large and getting into the narrow spaces between optical carotid cistern, or optical, or carotid oculomotor cistern, does not allow you to have the endoscope and two other instrument to work with. So I think working to design specific endoscope holder, I don't think you can rely on your assistant to hold the endoscope because, will be too much movement and it's not very secure. And the other thing is to have micro instruments that are better compatible with the use of Qevo endoscopes, so with the holder and the micro instruments that are compatible, you can really do actually this, the major part of the critical part of the surgery, having the endoscopic view and continue that part of the dissection, or clipping, or tumor resection, altogether. Thank you very much.

- Amir, Thank you so much. I wanted to ask a few questions. Number one, do you need to endoscopic training to use the Qevo? What are your thoughts there?

- I think it's ideal. Yes, because of just the difference between the two dimensional and three dimensional ward. Neurosurgeon by default, they are all trained with a three dimensional... microscopic visualization. And I think if you don't have that two dimensional training. will not allow you to progress in optimizing the benefits of Qevo during microsurgery.

- And just as a clarification for our viewers, you don't need an assistant to use the Qevo. It's very practical. It's attached to the microscope and it's very easy to use. So, with that, let's go ahead to our next lecture for, from Dr. Sivakumar from Pacific Neuroscience Institute.

- Okay. Thank you, Dr. Cohen Goodall it's always a pleasure for me to join you on these lectures. And they're really big highlights for me. I think my presence here, is going to be valuable for the young neurosurgeons in terms of trying to bring things back to earth a little bit here, you just watched two master neurosurgeon use these devices as, as young neurosurgeons where you're trying to get more I can to your neurosurgical and microdissection techniques. I want to also focus on the utilization of this device and a growing field in neurosurgery keyhole, minimally invasive neurosurgery. My colleagues, no specific disclosures for this talk. So, as we're progressing here, we're all trying to make surgical, or surgical intercranial treatments safer and more effective. So how do we do that? Some of the principles that you need to focus on as you're, as you're starting out your career, is this understanding that brain surgery, even though a lot of us think that is the be all end all, is really oftentimes the beginning of treatment. We want to aim for a maximum safer section, or a safe full aneurysm clipping while a restoring function and maintaining quality of life without avoiding, with, while avoiding new neurological deficits. Attaining sufficient tissue is vital. And the approach, in my opinion, needs to promote early mobilization, try to shorten hospitalizations stay, and optimizing the patient to proceed to their adjuvant treatments as they do when it comes to brain tumors, etcetera. So how do we accomplish this? The keyhole that our shop, we're firm believers, in keyhole surgery at the Pacific Neuroscience Institute. We think of it as assessing, accessing the brain through smaller more precise openings, to minimize brain scout, muscle manipulation. And as it pretends to this talk, it's really often aided by the use of endoscopy. Less bone removal, less soft tissue disruption, and less brain relaxation in our minds, preserves physiology better, which ultimately results in less collateral damage, a more rapid recovery and a shorter stay. When I talk about keyhole surgery, in multiple different ways, as it pertains to this talk, these are the four that are going to focus on, the supra orbital eyebrow craniotomy, mini teary on all approaches, and then grab assisted trans door on endoscopic approaches. Often, aided by the endoscope. So, one of the things to consider, for the more novice neurosurgeons is that the room setup is especially if we're going to use the endoscope or any type of micro inspection tool, is going to be vitally important. Patient positioning. Where are you going to put the microscope, where you're going to put the endoscope? Where are you going to put the micro visualization tools? Where are you going to put the monitors, are really important, to maintain a good efficient and more importantly, safe workflow. A recent study that we published, showed an over 130 supra orbital eyebrow craniotomy, endoscopy was used in 60% of the cases. And in half of those cases, additional tumor was able to be removed. Endoscopy of course has been around for a long time, started in a transsphenoidal surgery in the early nineties, with Dr. Joe and Dr. Corral and has really expanded beautifully. And the reason for it, I think is obvious. There's definite benefits to having that two dimensional, direct to the scene visualization. This is a view of a pituitary tumor, through a microscope while a beautiful technique and, used well by master surgeons. You can see bringing the endoscope into the field and expanding your field of view. And I know you've seen this in a multiple different arenas. You can see the additional visualization that you get. So extending that beyond the endonasal approach, bringing that down, I think it has great use in these keyhole procedures. The eyebrow craniotomy, as everyone is aware, can reach the extent in the entirety anterior... skull base, and a lot of the middle faucet, in my opinion. You can see the different regions of the anterior skull-based for these extra axial lesions. The same applies for intra-axial lesions, throughout the breadth of lesions coming from the anterior extent of the skull base all the way back to the brainstem. Additionally, I, in my practice and more recently, we've seen some great videos by Dr. Dehdashti but, I started using the supraorbital eyebrow craniotomy for aneurysms as well. And it's been really useful and especially adding the Qevo, I feel like has accelerated the recovery process for my patients greatly. You have great view to the proximal ICA, the PCOM enter the coronal region, the ICA Terminus, getting to both the proximal A1, even to the, as well as the anterior communicating artery. And I think it works well, for the proximal portion of the M1 as well. And you can get back to the vessel or artery as well, in certain cases. The endoscopy is especially useful in expanding that visualization beyond the hidden region, along the cribiform, ipsilateral optic nerve, that sphenoid wing and parts of the middle fossa. That are typically hidden by the microscope. We tend to use the eyebrow, more preferentially about five to one, compared to the mini-pterional approach with the pathology that we see in our shot. With the similar results, to other services. As well, I think it's shown great use in these gravity assistant approaches. These are a couple of our papers looking at them in a... contralateral trans fall scene approaches. As well as super cerebellar effort tentorial approaches. Some concepts to remember. Positioning is key as Dr. Dehdashti showed, that the venous dissection is especially important. We use the Doppler greatly, which helps allow us to increase the safety of our procedures. We aim for minimal or no retraction whenever possible. The angled scopes are essential, which is where I think this utilization of the micros inspection tool, the Qevo, is especially useful. A little bit different than our other speakers. I think it can be used safely, with the endoscope holder in isolation, or, when you have a trained endoscopist with you in a two surgeon, three to four handed technique. Here are a couple of the gravity-assisted supracerebellar approaches, can be used for a variety of lesions as was discussed previously. The standard positioning that Dr. Dehdashti beautifully illustrated in his earlier video. And you can see why there are some benefits to it. This is the positioning of my partner, Dr. Bark Darien, using the microscope for the supracerebellar approach and look how much more comfortable, how much closer he is to the field he is. And I think how much better able, he's able, he's able to use bimanual technique. This shows the video of a neuroenteric cyst in the poster left midbrain, using a, a transdural approach here. So now to the important part of my talk, my experience with this tool, and as has been discussed and illustrated, this is not an endoscope, and it's a really important point, the benefits of this tool to be used similarly to an endoscope for obvious. The fact that it's in the integrated work system of the Qevo, I think is a... a... a paramount importance and convenience, Ease of use, and the ability for a surgeon not to remove his hands from the surgical field, from his chair, to bring the microscope in, leaving the microscope in its position, and then being able to bring in the micro inspection tool they can't use with an endoscope. I think that's the reason the popularity of this devices is, is grown so well. And been used in my practice almost on a daily basis. It's a high definition, 45 degree angled visualization tool. I've used it in about 130 now, probably closer to 150 cases. And I'm using it for a number of different pathologies, hemorrhages, aneurysms, tumors. And I've used it in both ways, as a single surgeon when I'm using it as a for inspection. Typically when I'm using it for intervention, I'm still pretty... pretty rigid in that I want bimanual technique, if I'm going to be using it with another surgeon, so, that I'm going to use interventional... Use it as an interventional tool. The lighting, as I've found through the increase utilization of this tool, is especially important. There's variable setting on the... settings on the lighting, and it helps you in different ways, depending on where you are inside the brain, and what you're trying to do. So the ability to adjust the extent of lighting on your own, without requiring assistance is actually quite helpful. Here's a case in Dr. Dehdashti, it showed this really well. So this is a suprachoroidal IC turned out to be a complex immediately projected poster communicating artery aneurysm that I elected to treat through an eyebrow craniotomy. You can see there's really no limit in terms of the exposure that you can get from this procedure. You're able to split the poster communicate, are at the middle medial screen, Sylvian fissure, and a really great exposure of those distal vessels. After clipping off the aneurysm, bringing in the Qevo on this proximal end, as Dr. Dehdashti illustrated, you're really able to get a beautiful view of the perforator of vessels. I noticed here that I did get it in my clips construct. So I was able to modify the construct and get them free from that. Now coming on the other side, the lateral side of the aneurysm, we were able to come down, and show the residual neck of the PCOM that we tend to see, if the angle of the clip is not right. So noticing that, and noticing that the clip is a little bit too deep and connecting with the ocular motor nerve, I'm able to modify this clip construct. So we continue to modify these clip construct, to get better view of what's going on and subsequently, modify the construct and add clips as necessary. I'm electing here to leave more of a proximal neck, which is in my view, so that I can treat him with their mini clip afterwards. And we're able to get better clip, maintaining, removing the perforators out of the construct, while getting more of that proximal view. And getting more of that proximal neck while preserving the posterior communicating artery. I here showing that many clips and the ICG shows obliteration in the aneurysm or preservation of the other vessels. However, when I puncture the aneurysm, we still showed a good continued filling in the aneurysm. So we proceeded here as you can see, with the bolster clip, as we come around, we're able to see a complete obliteration of the aneurysm, preservation, a lack of contact on that third nerve. The patient woke up well and went home post-op day one. I did this case last week. I just saw her in clinic, and she's continuing to progress well. Here's the ICG at the end of the case. So I thought this was a very interesting case. You can start the video. So, what I started doing here, I think this is a good case to begin for, for user to especially if they don't have focused endoscopy experience. Dr. Cohen Goodall just, posted a great video on a subdural hematomas. He and I have very similar philosophies, that for the majority of these hematomas, where going to elect to do a craniotomy, you can achieve the goals of surgery, through these mini smaller craniotomy. And the Qevo in this case, has really helped my workflow. In cases where there are very significant membranes, on the subdural, preventing the brain from expanding. I've had... favorable results, bringing the endoscope to allow me to safely, with continued visibilitation, extend the opening of the subdural membranes. So that we can get from stem to stern, open up the membranes, allow for brain relaxation without losing control and making sure I can control the... control the... at the membrane, making sure I'm not allowing bleeding to continue in my blind spots. And you can see removal of this subdural hematoma. You can move tour, and here's another Qevo view. And it would these chronic subdural, that during tends to be highly, highly vascular. Since this video, we are a part of the embolize trial, and I'm electing more to do the MMA embolization for these really chronic continuous subdural that require more aggressive treatment. This is, I think, a good idea for a novice surgeon, specifically, those who don't have endoscopy training, to bring in the scope a little bit earlier into their practice to try to get used to using these inspection tools. And there we go. So this is a case you can start the video, where the navigation was actually off on a meningioma. And I know with more of these tailored craniotomy, this is one of the risks you run in one of the shortcomings actually of keyhole approaches, realizing that I brought in the Qevo, and was able to safely remove, by using the two surgeon technique, that residual tumor and still was able to, to remove the remainder of that tumor. Despite that earlier mistake. Here's the case I did a few weeks ago, which is to illustrate the point again, that this is not an endoscope and, Guido, who made these videos in a beautiful way. I think really shows if you can start the video. Where are the benefits in the endoscope are, but late into the micro inspection tool. This is a transcallosal transformed scene, transventricular approach to a vessel ganglia thalamic cav-mal though, that I felt was the safest approach. So you can see the approach that we came in here. So this is after we've entered into the cav-mal, and we continued that dissection through standard microsurgical technique. I want to focus more on the endoscopic view here. And so this is removing... the cavernoma. Important part here, The technological adjuncts are really important. You can see the single shafted instruments that we use during this video. This is, a carefully teasing and dissecting the catalyst malformation from the, the adjacent thalamus, to minimize... injury. We use a lot of, you can advance about 10 seconds, a subcortical mapping in this case to make sure that things were stable. And then, so this is the end after we removed the, that part of the tumor. And you don't really have a view of that distal wall. So this is the standard endoscope, and you can see I've left some residual approximately on the poster medial wall. That I'm able to remove here, through a single surgeon technique. But you see the difference between the standard endoscope. And then there's the, I love that ventricular view, but do you see the difference in the visualization that you get from the endoscope, versus the Qevo micro inspection tool. But still, able to get a great view of that distal wall to ensure that there is no residual cavernous malformation. And the closure, post-op per section and gross total resection with the MRI. And the patient a week after surgery, thankfully, neurologically intact. So, some of the things here as improvements in this device, you know, this is a technology that's going iterative improvements. And the fact that it's within our microscope ecosystem, allows us to, I think, I'm very optimistic, we're going to see significant improvements in this tool moving forward. I think it allows for a shorter learning curve For new endoscopy's as Dr. Dehdashti... mentioned. It's really helpful for someone to be trained in this, you know, preferably fellowship trained. But for those who aren't, it doesn't mean that you can use this device, because of that crank mechanism. It's going to allow surgeons who don't have that endoscopic tool, to get a little bit more comfortable, a little bit quicker. I think there is a need for a scope holder, that hopefully we will get here in the not too distant future. The ability to switch to maybe a variable angle, either a zero or 30 degree, in addition to the 45 degree would be useful. And as you saw in that last video, there is still quite a bit of room for image quality improvement. Which I anticipate will occur with the interactive devices Next. So in conclusion, you know, technological advancements have result in decreased morbidity and mortality in cranial surgery. Keyhole brain surgery is a safe and effective alternative to standard cranial approaches. The Qevo micro-inspection tool is especially useful in keyhole, minimally invasive cranial surgery. The use of the devices and inspection versus intervention tool. Really dictates the need of whether an assistant is necessary. Proper positioning and ergonomics are vitally important. A low profile micro inspection instruments, will make this tool more rentably used. And I think it's a worthwhile investment. And with that, I'm happy to take any questions, Dr. Cohen Goodall thank you again for this. It's always a highlight for me as we've discussed.

- Wally, always a pleasure to have you. Spectacular lecture, very well done, thoughtfully done as, as always your work has been. Amir, same to you, I sincerely appreciate your technical skills and your personal reflections here. What kind of cases do you think we should start with? You know, I have used Qevo very frequently. I've been very happy with it. It's just a simple tool. It's well integrated into microscope. And it just gives you what you want very quickly. Bringing it into scope is really cumbersome, and then really, catch between the two and endoscope hits the microscope and it's just, the workflow is not adequate. So I wanted to ask you to your final opinions, about this tool.

- So I think one thing to consider is that, it has to be mentioned that Qevo although it's a utilizable, but it has limited number of usage. I think is 80 or a hundred times where after that, you need to buy basically a new device. So although, it can be used, as you feel whenever you want, in every case, I think, financially, thinking about it. You have to also be, think, thinking about what cases would he need it and not use those 80 times, that it goes in vain if it's not really needed. I think if you're talking about the neurovascular surgery, proximal choroidal segment aneurysms. Specifically, as I mentioned supra hypophyseal, and anterior choroidal. These are very important. I, every time I have supra hypophyseal aneurysm, I request to make sure that Qevo is available, and if it's not, I do not, I do not book the case. I put it in another day. So I think this is as important as it can get for me now with this technology. And I think it's almost, I tell to my, OR people, with what we have, If I put an SHA aneurysm elective without Qevo, is a malpractice. Because, you can... create a significant neurological deficit for something that otherwise it's not visible. And we have an ability to visualize it. So, this is a, I think for vascular surgery, this is the most important. Some vessel or perforators also, but I think, those are actually easier to visualize with microscopic visualization because they are not necessarily hidden. Going, getting out from the vascular surgery. I think... Again, I think the three really tumors that are important is, Petrous apex. We just did one last Monday. Petroclival meningioma through a Kawaze. Kawaze opening is limited, is not a huge score based exposure. There are angles behind the IAC in the CP angle that you won't be able to see. And Qevo would really help you to visualize that, if there is remnants for meningioma or any other tumor there. Kawaze, for whatever, whenever you do Kawaze inside the internal auditory canal, because you have limitation to open the canal, because of the extension of the superior semicircular canal, and the third I really think quadrigeminal cistern, because the direction of the cistern is always wider than what the exposures can, can give you. Whether you go midline supracerebellar, or even if you go occipital interhemispheric transtentorial, you have a limited exposure. So I think these three areas are an absolute indication for the addition of Qevo during surgery.

- I would, I would definitely echo the settlements in deck, definitely agree. As we've been giving these lectures, that the residents always ask me and they get very worried, do I need to do a fellowship to do this? And, you know, it'll definitely make it better. And it'll definitely be able to make you use this thing more effectively. But for those who are unable to do that, I think there's still some utilization of the instrument, and probably the safest way to do it, is to bring it in iteratively, in earlier procedures where you already have a good view. And then you use it to, to get control of the device. I would say probably, you know, 20 to 30 cases of the device, being mindful of the finite level of uses, of bringing it into cases where you already have comfortable exposure, and getting used to using it. Because it is a different workflow, as Dr. Cohen Goodall mentioned, compared to the endoscope. You don't hold it in the same way. You don't move it in the same way. It makes it easier for your use of the endoscope, that you can still get the feel of it to make it useful for you to be able to look around those blind spots.

- I agree. I think the future improvements, including a handle would be a great addition. Because then you really can use the microscope that Qevo have it fixed in there as a by standard and be able to get multiple views, will be a great addition. But there is no question, even for simple procedures, like a parasite or meningiomas. Simple procedures, like some of the gliomas that are tucked in in difficult locations. This is a very good technical tool to have, to be able to pro extend your visualization to a new level. So with that, I want to thank both Amir and Wally for... being with us, great contributors to the... to the neurosurgeon Atlas. And thank Zeiss Meditec for their continuous development. And, really the... advancement in your surgical visualization. So wish all our viewers and all you guys great rest of your day. Thank you.

- Thank you.

- Thank you very much.

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