Image Guided Surgery Video Series, Episode 5 - 3D Printed Models in Orthopedics

Hi everyone. We are back with our series on image-guided surgery. I'm Elenid N. Cisco. And I'm M Tombash, research fellows at Cincinnati Children's Hospital Medical Center. And this is Stay Current Podcast. This series is really overall various conditions and children that can be taken care of in the hybrid operating room and and at Cincinnati Children's they've learned. There are lots of procedures that can be done using the hybrid operating room to do the procedures minimally invasively, for a lot of different subspecialties including general pediatric surgery, neurosurgery. This time we're talking with an orthopedic surgeon. Before starting today's case, let's briefly review some of the technology behind the biopsies that they get before this operation. Let's hear it from Dr. Jobm Ricardio. He's an interventional radiologist and the director of interventional radiology, research and innovation lab at Cincinnati Children's Hospital. Before we had expert guide, expert CT or expert guide, which we have in our interventional suites and in the hybrid OR. Expert guide is a technology that uses imaging, typically fluoroscopy and 3D images from CTs or MRIs to help clinicians perform percutaneous procedures more accurately. Neil would do these under CT guidance in the main radiology department. Previously, biopsies were typically done under fluoroscopy and kind of guesswork according to Dr. Johnson. And that's progressed to using CT scans around the late 80s where interventional radiologists like Dr. Johnson took a patient down to the main radiology department. We try and clean the floor and clean the stuff off the table and it wasn't a sterile environment. It was a sort of a clean environment. We never got an infection but it just wasn't good practice. That's all in the past now. Dr. Neil Johnson, an interventional radiologist at Cincinnati Children's Hospital. Then we moved along here at Children's to CT scans and we had certain cleaning protocols and all this other stuff. But I had actually a laser go that I used for like 15 years or more and it was very useful whereby you could choose a path on the CT scan to put the laser guide on and that would guide you but you did the spins outside the motor the table out, do the pin or the biopsy and then motor the patient in. So it was backwards and forwards, backwards and forwards. Then technologically came CT fluoroscopy whereby you could put your foot on the pedal and take a picture. But again, it was backwards and forwards. The disadvantage of that was just being static views. After you put a drill in or put a screw in, you could check its position with the flora, but you couldn't do it with the real time. Well, there's a massive radiation to your hands and other things. And secondly, you're trying to work in atry and some of these drills and screws are wider than thetry. So that that served us very well for a long time doing biopsies and osteoid osteomas andal bone cyst all over the place. And then as we moved up to the operating room and got this hybrid room, it's all come together because we now have a full complete operating room where you can do a liver transplant if you want to. It's a sterile operating room environment with plenty of space. So now we have the advantage of this totally sterile operating room. We do have this 3D CT scanner. It has somewhat angle limitations, but we've gotten pretty good at flexibility for the angulation. And as you put drills in your biopsy device, you can see what's happening to the drill and where it is in real time. And then you got a fluoroscopy while you're drilling. So it's the full hand. And then we're going to move on to the video imaging and tracking the patient, a few other things coming down the tube. I may be retired by the time some of them get here, but it's it's really cool to see the progression we've gone from the 70s, which was fluoroscopy and guesswork through the sophistication of what we got today. It's been a time travel. Let's get back to present to our case. So what is our case today? This kid had a relapse Ewings. I think he was treated up front with radiation and chemotherapy. And then despite the radiation, the tumor came back at some point. That was Dr. Joel Soldier. Is the director of the pediatric joint replacement surgery at Cincinnati Children's Hospital. What is the typical method for resecting this tumor in patients? Years ago, what we would do is just do our exposure, use the MRI, try to find some bony landmarks in the pelvis that we can identify, then just make some measurements either by feeling where the soft tissue mass is or if like this case, most of this is interus, basically just using a ruler and some landmarks and making some generous cuts and and then removing it then doing some sort of a reconstruction. And this case was a little bit different for Dr. Soldier. This was the first one he did where a company developed some basically CT manufactured cutting blocks. And in case you're wondering, this is a really fascinating process. It's really cool. You have a meeting with a manufacturer, they're able to fuse the MRI and CT. You tell them where you want to make cuts on based on the MRI and the CT, then they're able to give you cutting guides to the bone and they're able to use those during the surgery. And Dr. Soldier continues to explain. And then you pin them onto the bone, you make your cuts, you take the bone out and you have a defect and in his case we had the company also manufacture a metal implant that would fit into that space. So I had John available for this because I had never used the blocks before and in case the blocks didn't work, then I would use the CT as a backup. In this case, Hybrid OR helped them a lot because the blocks came broken. So they made some cuts using the fused images just to double check their measurements, landmarks, and everything else to say that they're outside of the tumor. The first MRI was the pre-op MRI that was done at Children's and that shows basically that mass above the acetabulum with really no soft tissue component to it. And on the screen here, you can see the planning CT. And then they fuse the CT and the MR together. You basically sit down with them and say, these are I want to make my bone cuts and or I want 3 centimeters around the tumor, they'll put a bubble around the tumor at 3 centimeters. And then they use their design equipment to design to determine where those cuts need to be made. So you can see the piece in that's they're holding is what they're going to remove from the pelvis and in the other hand, the left hand is what the residual pelvis will be after that piece is removed and this is all generated by a 3D printer. That's the model and the cool thing about it is that model can fit into any defect because the model is made for the defect. The screws are all planned out by myself and the engineers where we want to target them because some of the screws go up close to the sacrum and so you have to make sure they're targeted properly so you're not in the neural frameman. Same thing those screws that go into the Ramos and we don't always expose the vessels so you just want to make sure the screws are outside the vessels. But the screw sizes, the screw trajectory are all pre-planned based on the CT and the MRI. So there's just the planning after the patient's on the table in the hybrid OR, we're able to do a CT scan interrupt there at the beginning of the procedure and then fuse the prior MR with that CT and plan with Joel where he wants to do the cuts. Um, so this is just showing the acquisition of the CT scan. Um the patient was on their side as you can tell, the CR rotated around the patient and acquired the images and then so basically you generate the CT images. And then we do our exposure just like we normally would for a pelvis resection. Once we get our exposure, normally we would find a bony landmark, we could key off of or maybe the soft tissue mass, just make some cuts. We did the CT scan after the soft tissue exposure and then fuse the MR to that CT and with the patient in that kind of decubitus position. So in this case we did the exposure, we put on the blocks. The blocks come with holes for pins. So we use those pin holes and I may have added a couple more pins and then you did your acquisition to see where those pins are sitting. We usually have them exposed first because there can be a lot of motion when they're exposing. That was Nicole Hilvert. She is the manager of Translational Research and Simulation Lab at Cincinnati Children's Hospital. And that will help us with their guidance later. We don't want to move the patient. Yeah, so it's important obviously once you do the scan that the patient doesn't move. So they've got to be taped down pretty well and they've got to be under thorough proper anesthesia and the whole thing. It becomes very important in other areas of the body such as the chest, which we've talked about previously, there's a podcast on that. The pelvis is a little bit more rigid and doesn't tend to move. So they can't be moving even a few millimeters, otherwise the the scan doesn't know where the patient's moved to and you're subject to errors. acquired CT scan and MR can be viewed out either side by side or or fused together over each other. In addition to looking at them in a traditional planar fashion, we can look at them with a 3D rendering. The scanner has the ability to some navigational capabilities so you can plan target point and an like an entry point. Joel had basically had had hand seen this pin over the graphics that we planned to get the pin at thetic notch where we wanted to on the CT scan which was going to help I believe as a starting point for one of his cuts. And then here we're showing what it looks like after you take it out. Yeah, that's the specimen. Uh, and you can see how it's kind of similar to the the planned cut that is in the forefront there. So in addition, what was helpful Joel is the ability to do a post stop CT while the patient still on the table looking at screw placement and such. And here's a tip from Dr. Soldier. It's really good for screws especially if you're around the sacrum. It helps a lot. So I guess overall it sounds similar to localization using this process. You know, being able to do it in the hybrid operating room saves time and transportation for the patient. Yeah, well I think it could be different for each individual case. You can take advantages of the hybrid OR for, you know, pre-operative imaging. You can fuse things as needed. You can use it for some navigational capabilities and certainly you can use it for interrupt checkup as well as post top. I think on the whole spectrum of the hybrid guidance, some of the things we do, we couldn't do before safely. that's one side. Some of the things we do, it's essential to get parts of the case done. It's nice to be sure, you have increased confidence that your screws and stuff are in the right spot. For things like this, it's pretty cool, you know, the next advance in the technology is some kind of antenna you can put on the bone so that we don't have to worry about motion and it can be a little bit more accurate to where you are. But for things like this, it's it's really good. For me at this point more of a backup just because I think that the CT guides that they create now are so much better, but yeah, it's got a lot of uses. But there's all sorts of amazing technology and guidance systems coming down the track. Okay, awesome. So super cool way, you know, like I like we said, the hybrid operating room can be used for and by a number of different specialties to improve patient care in terms of, you know, being able to do things as minimally and basially as possible and as accurately as possible. In this case, we took a patient with relapse Ewing sarcoma and we're able to resect and repair their pelvis using this amazing technology that harnesses the power of both CT, MRI, 3D printing. Don't forget to subscribe to our YouTube channel. Leave us a comment, a rating on Apple podcast, Spotify wherever you're listening. And as always, don't forget to download the Stay Current and pediatric surgery app. It's on the Apple App Store, Google Play Store. Until next time, I'm Elenid N Cisco. And I'm M Tombash. And this is Stay Current Podcast.