Grand Rounds-MIS Lateral Retroperitoneal Approach (Part II): A Review of Cases
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- Hello ladies and gentlemen and welcome to part two of our discussion regarding minimally invasive lateral approaches to the spine. The first part discus principles and anatomical considerations for this approach. And the second part will expand details regarding more complex and expanded approach for minimally invasive routes to the lateral spine. Dr. Bill Taylor, Director of Spine Surgery at UC San Diego and Dr. Juan Uribe, the Director of Spine Surgery at University of South Florida, all our guests. Thank you for your time and Bill and Juan please take it away.
- So our second part of the presentation include the expanded applications of the minimal invasive approach. And when we call expanded applications, it means cases with significant complexity. So high-grade spondylolisthesis, revision cases, deformity, trauma, tumor and osteomyelitis, when the surgical indications exist. So in order to be able to perform expanded applications of the lateral axis, you need to get a significant grade of sophistication in terms of implants or instruments. And not only that, but the surgeon has to be on a good point on the learning core. As we see here on this slide, there is at least 10 or 12 different type of implants and each one has his own application. And on these presentation we will going to see some of those applications and as long as we know most of these applications are already validated on the literature. And the first good application is the herniated thoracic discs. On the first video, we're showing a case on a patient with a calcified mid-thoracic disc. So the technique is the patient on lateral position. The incision is driven by the fluoroscopy image. The incision is usually parallel to the rib. that is corresponding to the index level. The intercostal muscles are dissected until the pleura is identified. Once the pleura is identified, the dilators are placed transthoracic or retropleural depending of the type of approach. And then the retractor is opened at the index level and on the lateral view, localize over the area that has to be a target. So as we see here on the AP view, once the level is identified first working anterior into this space to take some of the loose fragments of the disc space and away from this spinal canal. Once we get there, the option is now to create a small cavity, a small partial corpectomy in the posterior third in order to be able to handle the calcified part of the ligament. So to make it clear, this patient, now on their magnification on the fluoroscopy, the retractor was placed, this is a, can I get a pointer in here? So anterior is on the superior part of the screen, posterior on the anterior part of the screen. And then as we see here the dura is exposed. The partial corpectomy in front of the dura elements was made with this case high-speed drill. And the idea of creating this cavity is to able to mobilize the herniated fragments towards the defect instead of placing pressure on the dural, on the spinal cord, on the dural elements. So little by little, on their magnification get access to the herniation. As you see is very important at the beginning to remove the head of the rib drill, partially the pedicle in order to have exposed of the neural elements and that way keep moving towards the midline, as we see here, working these angle instruments and always getting away from the neural element itself, working on the cavity that is created. So once you get access to entire canal and release the part that is calcified and released from the posterior in a ligament then is matter of explore the canal above and below for remanence of the herniation. When is adequate decompression, the last part of the procedure since the particles were removed and this potential for instability, in this case a interbody fusion was made, placing a cage at the level. It may be or not instrumented, with this case with a lateral plate. And this is the final view of the instrumentation. Dura is posteriorly the plate. And then we remove the expandable retractor on in this case make sure there is no injury of the inter-thoracic structures. And this is the image pre-op, we see the calcified lesion. And then on the immediate post-op CT we see how you treat the pedicle take the grip. And this is the final images, the osteotomies that are needed for that particular case. So as you see here, you can from lateral through the index problem without the need or create a significant incision and you're able to deliver the same outcomes and results. Dr. Taylor I know that you've done a lot of these procedures, any comments on the thoracic discectomy using the minimally invasive lateral axis?
- The technique is been well-refined by you over the years and I think the key thing is really the exposure and those making some sideways sort of cuts to funnel the dura to gain access so that you can decompress the disc into the space you created. If you can't see that anatomy you're not doing an appropriate surgery. And it's not simply a lumbar X lift in the thoracic or lumbar minimally invasive lateral approach in the thoracic spine. It's a completely different surgery. And it's something which you need to make sure that you practice before you do it. The second thing is that it really changes your anatomy depending on where you're at in the thoracic spine. So lower thoracic may look more like lumbar, upper thoracic you know you're gonna have to do more and more rib work. And I think you'll find that the people's biggest concern is really going through the chest in the thoracic cavity, which really becomes less and less of a problem over time. It's not something which is a concern, it's really the technique of the surgery itself. I worry less about approaching and getting into the thoracic cavity than I do about the surgery now.
- Yeah, totally agree with you. And, so the main point is that the procedure once you get into the head of the rib is actually the same procedure that we're doing for the last 20 to 30 years, It's just the access that is very refined and just to the index problem. But once you get into the surgical field, you take the rib exactly as you did before. You have to create a cavity so you can move all these fragments toward the cavity instead of creating pressure or even injury to the spinal cord. So don't forget this is not a lumbar disc removal, this is a thoracic disc where every structure is critical. So we can go to the next video. So in this case is we're gonna recover exactly what we saw. On the first case is a T8/9. And as we looking here, in this case is again a calcified and we're going to give even more details. Now on this video you see a big calcified lesion on the mid thoracic spine, as we see on the MRI and as we see the calcification on the ACI pre-op. So in this case, an access from anterior is a good option. So again the incision is guided by photoscopy over the rib at the problem, what the problem is. The in this case we doing the access totally retropleural. So once you get into the index level, as you see here, anterior is on the superior area of the screen. This posterior is where I'm working right now. And you see the amount of the partial corpectomy that was made in order to be able to mobilize the calcified fragment as we see here, anteriorly and not making any pressure into the neural elements. The pedicles are totally removed as we see here. So that's why the dura it is exposed. So the first part of the procedural is aimed towards be able to identify where the neural structures are and then, using microsurgical techniques, releasing the fragment that is calcified on the dura above and below until you create like an island of a bone around the dura and little by little you do your dissection until you can remove the offender fragment. In this case as you see is totally retropleural the approach. You see us removing the retractor. You pay attention you can see how the lung is behind the pleura. So this one actually make the procedure even more elegant since there is no need for chest tubes. And as you see here the amount of bond resection that you have to do in order to be able to negotiate that big fragment. So you see post-op image, you can have really good results even on what we call giant discs. You see how posterior you can go with the resection. This is the amount of the osteotomy and this is the MRI post-op. So, again it's an elegant way to get into a problem. This is actually a testimonial of the patient, 24 hours after the procedure. And something that if you have to create a full thoracotomy with chest tubes, I think it's very hard to make the patient ambulate the next day. So, that was another example. Dr. Taylor, do you do a retropleural approach? Any tips on how to get access retropleural or you rely on transthoracic approaches to the thoracic spine from lateral?
- I think both of those are really really good points. I rely not just on transthoracic approaches. But the reality is that, I wouldn't concern myself as to whether it was transthoracic or retropleural. Because often if you start out with retropleural, in my experience about 50% of the time you end up transthoracic. And I think that also the older the patient gets just sort of like the dura the easier it is to tear the pleura. So I try to stay retropleural, I try to open that space, but in the reality is it really doesn't change the long-term prognosis, it doesn't change the outcome. And it really doesn't affect the surgery that much to my mind whether you go retropleural or whether you have to go transthoracic. So I see people that are concerned if they tear the pleural, the more and more they talk about retropleural. They become concerned that, oh, I've torn the pleural, what do I do now? And it's not really a problem. A soft drain for a day and another day in the hospital will take care of that. You don't need to put a chest tube in. And it doesn't really change anything. So the critical thing is really thinking about the anatomy at the location of the surgery and to just deal with whatever access you can get at the time of the surgery.
- Totally agree. Can we show the next video? So in this case is the same minimally invasive lateral axis, but in this case it's in a patient with a metastatic breast tumor, with significant neurological compromise and a significant, as we see here on the images, a compression of the neural elements. And in this case what was interesting is that the betterer below has some amount of compromised, but since we using these expandable cages after doing the corpectomy, it provides a really good stability. And this case again, a retropleural exposure. And you see the implant that has a white footprint actually allows to limit the corpectomy to one level instead of two level corpectomy and just decompress the neural elements and the patient to go towards the coagulant treatments. And since you are retropleural and you're not communicating the thoracic cavity to the tumor cells and you're doing a small incision, these patients actually can have access to a coagulant treatment in a more expedited manner that with a standard access corpectomies. Do you do tumors to the lateral axis Dr. Taylor and how do you do them? Are you considering this approach on this population?
- Absolutely, I mean the reality is that the further expansion of using minimally invasive surgery really changes your ability to take care of the unfortunate metastatic patients who may have limited life expectancy, multiple other issues or multiple other metastatic lesions and sometimes are quite sick. So the advantages you gain of minimally invasive surgery are multiplied in these patients. The transthoracic approach works very very well. And as you know, more and more people have sort of now gotten to the point where you can do a wider and wider decompression, you can do stabilization through a single incision. And it works very very well from the thoracic spine from about T5 down into the mid to lower lumbar spine. So really the benefits of minimally invasive surgery are multiplied in this patient population.
- To finalize this presentation, the points to consider are first the expanded applications of the lateral are basically thoracic herniated discs, tumor lesion, also infection cases, in case of osteomyelitis, when the deformity precludes the treatment and the antibiotics are not able to provide the current treatment and any other circumstances when you need to do a corpectomy. The important thing is that once you get inside and you start working on the target problem, the microsurgical techniques are absolutely the same. Is the approach what is really having a significant difference and the technology has been able to provide the instruments to work through an expandable tool. But at this point I believe that is a really good option, it's a significant learning curve as any other minimally invasive discipline. But I think provide that really good outcomes to a selected patient population.
- Well gentleman, Bill and Juan thank you for a very instructive part one and part two sessions. And we look forward to having you with us in the future. Thanks again.
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