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BackTable / ENT / Article
Pediatric Skull Base Surgery: New Technologies & Techniques
Iman Iqbal • Updated Oct 31, 2024 • 35 hits
Pediatric skull base surgery presents unique challenges due to the delicate anatomy and vulnerability of young patients. Common conditions such as hypophysis abnormalities, Rathke's cleft cysts, and chordomas often require intricate surgical interventions, with a significant emphasis on minimizing trauma. The collaboration between disciplines, such as neurosurgery, ophthalmology, and otolaryngology, plays a vital role in determining the best course of action.
This article explores the evolving landscape of pediatric skull base surgery, focusing on the integration of cutting-edge technology like 3D modeling, virtual reality (VR), and neuronavigation to enhance surgical planning and execution. However, as advanced as these tools may be, the human element—communication, compassion, and trust-building with young patients—remains just as critical. With a blend of technological innovation and compassionate care, surgeons are achieving remarkable outcomes in even the most complex cases.
This article features excerpts from the BackTable ENT Podcast with otolaryngologist Dr. Cristobal Langdon. You can listen to the full podcast below.
The BackTable ENT Brief
• Pediatric skull base pathologies include hypophysis abnormalities, Rathke's cleft cysts, meningiomas, chordomas, and gliomas, often requiring multidisciplinary collaboration for diagnosis and treatment.
• Transnasal endoscopic techniques are preferred for minimally invasive surgeries, reducing facial trauma while achieving effective oncological outcomes.
• 3D modeling and advanced imaging are essential tools for pre-operative planning, allowing surgeons to simulate procedures, especially in cases with intricate anatomy.
• Virtual reality (VR) is being increasingly adopted for surgical simulations, helping surgeons refine their skills and reduce damage in delicate surgeries.
• Neuronavigation, though helpful, should not replace fundamental anatomical knowledge and hands-on skills, which remain crucial for successful outcomes.
• In pediatric cases, fat grafts and multi-layer reconstructions are often favored over nasal septal flaps for repairing cerebrospinal fluid (CSF) leaks.
• Surgeons prefer using dissolvable packing materials like Tisseel or gel foam for post-operative care to avoid complications like crusting.
• Building trust with young patients through clear communication is key to their cooperation and reduces fear, leading to better surgical outcomes.
Table of Contents
(1) Common Pathologies in Pediatric Skull Base Surgery
(2) Skull Base Surgery Planning: The Role of 3D Models & Virtual Reality
(3) Neuronavigation & Intraoperative Techniques
(4) Autologous Grafting & Packing Materials to Optimize Reconstruction
(5) Integrating Technology & Compassion in Pediatric Skull Base Surgery
Common Pathologies in Pediatric Skull Base Surgery
Common pediatric skull base pathologies include hypophysis abnormalities, Rathke's cleft cysts, meningiomas, chordomas, and gliomas. Typically, these cases are referred to ENT from neurosurgery or ophthalmology. There is then significant collaboration between disciplines and their tumor boards, where the surgical team often suggests minimally invasive options for cases initially considered for more traditional approaches. The use of transnasal endoscopic techniques allows for safe, effective surgeries without the need for facial incisions, minimizing trauma to children’s faces while providing good oncological outcomes. There is also ongoing advocacy within the multidisciplinary team to demonstrate that these techniques can be a viable option for patients requiring skull base surgery.
The patient demographic spans from newborns to 21-year-olds, with older adolescents and young adults being rare cases. For new cases involving patients aged 21, the typical practice is to refer them to adult facilities unless the pathology is extremely rare or unique. This age-based approach helps ensure that patients receive appropriate care based on their developmental stage and the nature of their condition.
[Dr. Gopi Shah]
What are the common pediatric skull-based pathologies that you see and how do they usually present to you?
[Dr. Cristobal Langdon]
Mainly hypophysis and, I don't know, Rathke’s cleft, some meningiomas, chordomas, gliomas. We do a lot of biopsies because, in children's chemo and all these, they work really nice. We do a lot of biopsies. Usually at least all the cases are referred from another hospital, going to the neuro or going directly to us or to the ophthalmologist. To be honest, usually it's via neurosurgery or via ophthalmologist. Because now we are trying to get known that we are doing this thing and we have the possibility and all the armamentarium to do this thing. That they send cases to me is really rare. We are working on that.
[Dr. Gopi Shah]
Most of the cases for us also came through our neurosurgery, because in endocrinology, if they had an initial presentation, they would send it to neurosurgery, they would sometimes have their tumor boards. Then if it was going to be a transnasal endoscopic approach, then that's when I would get involved as well.
[Dr. Cristobal Langdon]
In the hospital, we have this tumor board, this neuro tumor board and body tumor board. I'm in both. Sometimes they start talking about some cases and I have to raise my hand and say, "Hey, maybe we can do this." Nowadays, we don't open the whole face. We don't destroy these kids' faces. We go through the holes and it's really safe and it's with pretty good results. Actually, the oncologist and the radiotherapy say, "Ah, it's really, you can do that?" "Yes, yes we can do so." That's another route that can have some patients. We have to fight a little bit in a good way.
[Dr. Gopi Shah]
Tell me first, before we get into that, tell me the age range that you normally see.
[Dr. Cristobal Langdon]
From newborn to 21. Actually, the eldest patients, like over 18, are really special cases. We have been treating them since when they were kids and we just follow up. To be honest, if we receive a new case of 21, it would be a little bit tricky to treat it at the hospital. We have to send them to an adult. Less is a really rare disease and a really rare scenario.
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Skull Base Surgery Planning: The Role of 3D Models & Virtual Reality
3D modeling and advanced imaging techniques are essential for pre-operative planning. When deciding whether to use 3D models, the surgical team considers whether traditional approaches may be insufficient or if the case involves intricate anatomy, such as in chordomas or meningoceles of Meckel's cave. For these high-risk cases, the team prints one-to-one scale models to simulate the procedure, assess the angles, and ensure instruments will fit within the patient's anatomical structures. This process helps determine the safest surgical approach, allowing surgeons to visualize and test the surgery before operating on the patient. The models, developed using cutting-edge printing technology, provide realistic textures, giving surgeons a tangible sense of the anatomy’s complexity. For particularly challenging surgeries, like those involving areas affected by radiotherapy, these models help prevent potential complications, such as destabilizing joints or damaging critical nerves.
The 3D modeling process involves close collaboration with neuroradiologists, who segment and fuse CT and MRI images for accurate printing. Surgeons work with engineers to refine the models, ensuring they are anatomically precise. These models allow surgeons to simulate the procedure, test instruments, and plan the best approach. Additionally, with advances in virtual reality (VR), surgeons can now use VR to simulate surgeries in a virtual environment, enhancing preparation, real-time collaboration, and surgical education. Together, 3D models and VR are transforming pre-operative planning and training, making them essential tools in modern skull base surgery.
[Dr. Gopi Shah]
How do you decide which cases you're going to do a recon on or, go further with preparation with some of the 3D models?
[Dr. Cristobal Langdon]
The easy answer would be that when we are not sure if going from it front, it's the best way. We really like to do a reconstruction and then see the case in all 3-dimensions and try with the neuron, try to see which is the better way, the better approach. That's easy. Then to be honest, when there is a complex case like the chordoma that you saw in Lincoln, this is because I wanted to do the surgery on the model before I go with the kit. Because the patient had radiotherapy and we are going to do a big chordoma, a lot of radiotherapy there. We wanted to see if we could reach and we had to go behind the odontoid and we didn't want to destabilize the cervical atlantoid joint and we didn't have to do a spine fixation.
We talked with the neuroscientist, okay, let's try it, let's print it, let's try it if the scope of our scope and the different angles allow us to safely remove this tumor. There are both two reasons. Now we have a pending case, this meningocele of Meckel's cave, but it's really posterior. We're deciding which is the best approach if we go from in front, from lateral, from the ear, because it has a facial palsy. We are going to print this case and do the surgery and try to decide which is the best way.
[Dr. Gopi Shah]
That's amazing. The models are big enough to where you can simulate instrumentation.
[Dr. Cristobal Langdon]
No, it's one-to-one. That's the amazing thing because when they printed this model, I realized, whoa, this is really tiny. [chuckles] It would be difficult. It's really tiny and the nostrils and nasal fossa, it's small. That case, then we did another case, I went to Leuven to do a similar case, regrettably was far more advanced tumor, far more difficult one, and we couldn't achieve cross total resection and we printed and yes, but the model really gives you an idea of what you're going to do. If not, if on the MRI, the MRI on this big screen, you say, "Oh, that's easy." Yes. You go there, ping pong, ping pong. Then you have the model. I told the engineers, "This is correct. This is the size. Are you sure?" Yes. I have to think twice before I go. Yes, I think that's an important part of this technology.
[Dr. Gopi Shah]
What percentage of your cases then do you usually have a model for those reasons?
[Dr. Cristobal Langdon]
Actually the printer that allows us to do this is brand new. I think that the first model was the one that we published on LinkedIn. Now we are preparing a paper, but because of the technology of this printing they allow us to print in different textures. It's a really nice brand new technology printer.
[Dr. Gopi Shah]
That's amazing. From an ENT standpoint, what kinds of teaching or information do your engineers need to know from your perspective? Are there tweaks or-- I know you talked about size and making the size a little bit more one-to-one. What else did you have to help convey?
[Dr. Cristobal Langdon]
To be honest, the one who works more is the neuroradiologist, Dr. Gómez Chiari. They have to do the segmentation. That's really, really there. The work is doing the segmentation and doing the fusion between the CT scan and MRI. From my side, I go with them and say, "Okay, we need to localize." For example, in that case, hypoglossal canal, hypoglossal nerve, six nerve, we have to really try to see both carotids, in that case it was both jugular bulbs and yes, and the pition. Then they have to segment all this information in order for the engineers to print them. They give them STL is like a format of the archive and they post-process it on special software. They first do a 3D reconstruction. Then we check if the 3D reconstruction is okay. Then they print it.
[Dr. Gopi Shah]
I was going to say, when you're looking at it or doing the simulation to see if your instruments fit, do you do that in the lab? Do you go to the OR in a special room? How do you actually test it?
[Dr. Cristobal Langdon]
Yes. I'm working to have a really nice lab, but this is one of my goals from this '22, '23 year, because yes, I'm only one year in the hospital, so I just arrived and we are working on that. Yes, that's the goal. Actually this is really new information. I tried it on Friday, but we are preparing, like going to Metaverse and doing surgery there.
Neuronavigation & Intraoperative Techniques
In complex skull base surgeries, the use of image guidance or neuronavigation varies depending on the case and available technology. While neuronavigation can provide significant benefits in complicated cases, it is not always necessary. The importance of being able to operate without relying solely on navigation tools is emphasized, as over-dependence on technology can prevent surgeons from fully grasping the anatomy and nuances of the procedure. However, for teaching purposes and reducing learning curves, especially for fellows, neuronavigation is invaluable. Surgeons also emphasize the importance of mastering anatomical knowledge through traditional methods before integrating navigation systems into their practice. Additionally, instruments specifically designed for image guidance, though helpful, are not always necessary in every case.
In pediatric skull base surgery, detecting cerebrospinal fluid (CSF) leaks sometimes involves the use of intrathecal fluorescein, though this is reserved for cases where imaging is unclear or doesn't align with clinical suspicion. Surgeons primarily rely on four-millimeter endoscopes, but smaller scopes may be used for infants or specific anatomical challenges. When repairing CSF leaks, multi-layer reconstruction is typically favored over nasal septal flaps in children due to the small size and limited effectiveness of the flaps in this population. These techniques underscore the need for a careful blend of advanced technology and fundamental surgical skills, particularly when operating on delicate pediatric patients.
[Dr. Cristobal Langdon]
In complex cases, I [use image guidance]. To be honest, we always train and I train without. Not because we don't believe in it or because we are lazy. I think that's what could be the real reason. For medical legal reasons, at least here in Spain, it's not that necessary. On the contrary, in the States, I think there's no way you go inside without navigation. The other issue is, for example, when I do some cases in my OR we don't have navigation. We have a really good view, but it's from the neurosurgeon. When we do complex cases, we do neurosurgical navigation. If not, we don't use it. I would like to have one. To be honest, it doesn't matter to me. Now we will publish in the course, but we are starting the first pediatric ENT fellowship.
We are going to announce it in the course. Just for that reason, I think it would be important for us to have navigation because it really shortens the learning curve of the fellow. On the other hand, this is just my opinion. I think neuronavigation doesn't allow you to really understand the anatomy and your patient because you trust too much on that. Because I really have to study, I really have to have the CT scan in my brain. I do it in like five minutes, but it gets stuck in my brain. I always know where I am, but I understand that's not ideal. We need to mix the two.
Sometimes I've missed neuronavigation. It takes more time if you don't have it. If you have, and you're completely sure, okay, you go ahead. If not, you have to be more gentle with everything.
[Dr. Gopi Shah]
I find it helpful. I agree that you can't rely on it. I think the more and more that you do, and depending on the patient's pathology, there's going to be times where you don't really look at it. Then there's going to be times where it's the under-pneumatized sphenoid sinus or my neurosurgical colleague trying to figure out how much tumor to take out or not. It definitely has its role, but you're right. It can't be the crutch. We can't just depend on that. When you're teaching, it's very helpful to make sure we're all on the same page. [laughs] We got to be on the same page.
…
When you do have navigation, do you have instruments that are image guided? I think that can sometimes be controversial too. Some people like image guide instruments and people don't use them. Some people use them just for teaching. Any thoughts on that?
[Dr. Cristobal Langdon]
Yes. I tried some of these neuro-navigated instruments back in the hospital where I did mainly adults or only adults. They are nice to be honest. I don't think they are better than normal instruments. Nowadays we don't have navigational instruments. We only have the pointer and it works fine. Regarding navigation during surgery, at least for me, it's more important the echo doppler than the navigation, yes.
[Dr. Gopi Shah]
Yes, I agree. Ours is pretty much just the pointer when we need it. We don't tend to use navigational instruments, although I think the ability is there. Again, in those rare cases where it's super under-pneumatized, which might be maybe once a year, that might be a time to use it. Technically I don't tend to use those very much. In the OR, when you do have navigation, do you-- like the CT? Do you ever fuse the CT and MRI? Do you just do MRI? What do you like?
[Dr. Cristobal Langdon]
We do the fusion, yes. Always.
[Dr. Gopi Shah]
Then really quickly for CSF leaks, do you ever consider using intrathecal fluorescein or any of the light or anything like that in those cases? Those aren't as common, but every once in a while they'll come in too.
[Dr. Cristobal Langdon]
Yes, sure. When we are going, for example, for a CSF leak and we have to find this leak, we put fluorescein always. We don't use the blue light and it doesn't help. You can see the fluorescein bright in there. What we don't do is to put fluorescein on every case, just on the cases where we are going to look up for the CSF.
[Dr. Gopi Shah]
For us as well, it definitely was rare, I can only think of maybe in the last nine years, maybe two or three times that we've used intrathecal fluorescein. Those were rare cases where we just-- on the imaging, you had a beta two positive sample, but the imaging just wasn't quite as obvious. Maybe something like that. It's something where it's just like, I'm pretty sure there's something going on or every once in a while there's some history, but those can be really tricky. We're not doing it on the encephalocele that you find or see or the obvious, but it's every once in a while where it's just not quite matching up.
I agree with the special light thing, we never use any of that either. What else? Am I missing anything? Do you tend to probably use four millimeter scopes, ever using the 2.7 for any reason? Anything else I'm missing? I'm just trying to think of other special pediatric intra-op skull base things.
[Dr. Cristobal Langdon]
Actually for the skull base, I've always tried to use the four millimeters. If not, we use the otologic. I think it's three millimeters for the endoscopic tympanoplasty. I think it's not 2.5, it's three millimeters scope. The issue, at least what we have, it's that it's a little bit blurry on the outside. I don't know why. It's not as good as the normal one, the normal four millimeter, actually the last case we have to do, we did a glioma of the nasopharynx. Actually I published, I think in LinkedIn, it's really nice case because we were able to see the middle ear through the mouth.
…
[Dr. Gopi Shah]
I guess just really quickly, nasal septal flaps, I assume you use those when you need to, when there's a high flow leak or when do you tend to use them?
[Dr. Cristobal Langdon]
I use it when we are trespassing a cistern because automatically it's a high flow CSF leak. The issue is that the nasal septal flap in kids, it's really, really small. Yes, I don't trust it too much. I do a really multi-layer reconstruction and then put the flap, but I trust more on the multi-layer than on the flap because it's a really small flap in kids.
Autologous Grafting & Packing Materials to Optimize Reconstruction
In pediatric skull base surgery, multi-layer reconstruction is critical, particularly when repairing CSF leaks. Fat is frequently used as a graft due to its pliability and effectiveness in filling defects. When necessary, lyophilized fascia lata from a donor or fascia lata and temporalis fascia from the patient may be used, although this is less common in children to avoid morbidity. Surgeons also incorporate Dura form or biodesign materials, and may add small bone chips or cartilage, for structural support, especially in high-flow leak cases.
The nasal septal flap is employed only when absolutely necessary, such as for extensive pathologies like craniopharyngiomas or when dealing with patients who have undergone radiation. In cases where the flap might be needed, surgeons may perform a "rescue flap," adjusting the pedicle while waiting to see if it will be required.
For post-operative packing, surgeons typically use materials like Tisseel or gel foam to support healing, while avoiding materials like Surgery Cells, which tend to cause crusting. Nasopore, a dissolvable packing material, is often preferred for its bulk and ability to hold the reconstruction in place without the need for further intervention. Post-operative care further includes the use of saline rinses to promote healing, but specific practices vary. Some start with mist before transitioning to full rinses, while others may begin rinses sooner based on the individual case.
[Dr. Gopi Shah]
Tell me about the multi-layer. Are you doing synthetic stuff, fat? Do you ever do cartilage or bone pate or anything like that?
[Dr. Cristobal Langdon]
No. I like fat. We had this lyophilicide, Facialata. It's like from a--
[Dr. Gopi Shah]
The thigh? The leg?
[Dr. Cristobal Langdon]
From another patient. Yes, exactly. In cases I really like Dura form and then fascia lata. When that fails, I really like to extract fascia lata from the patient or temporalis fascia. Depends from autologous material. In kids, I try not to do it because of the morbidity.
[Dr. Gopi Shah]
For us, if it was a large spatial defect intracranially that we needed to fill some space, we would get fat.
[Dr. Cristobal Langdon]
Yes, fat is amazing.
[Dr. Gopi Shah]
I agree. I never just relied on the nasal septal. We used a lot of biodesign and then every once in a while would get little bone chips or cartilage from the septum or the sphenoid rostrum. Actually my neurosurgeon, Dr. Swift, taught me that. At first, I was like, how is this going to-- it's rigid. He would just help tuck it in, like an inlay, like a plug, like a gasket almost. Then if there was a high flow leak or a pathology, like a craniofrenulum or something that we're like, we're going to need that nasal septal flap, then those kids got those as well. If you were going to use a nasal septal flap, did you usually harvest that at the beginning of the case or wait and see what you needed at the end?
[Dr. Cristobal Langdon]
Yes, exactly. Unless I already know that I will have to use it. For example, when we're going to the sphenoid, whatever, I do like this rescue, the so-called rescue flap, but it's no more than push down the pedicle and then remove everything, yes. If I need it, I raise the flap. If not, try to leave it as it is.
[Dr. Gopi Shah]
Yes, I agree. If it's a pathology that I know I'm going to use it on, such as a craniopharyngioma, we're going to raise it. Potentially somebody that's already been radiated and there's going to be extensive dissection. We're going to do it. I learned my lesson to just wait. Then after you've done your layers, do you usually do any packing, dissolved packing, mirror cells, anything like that?
[Dr. Cristobal Langdon]
Yes. I put like a Tissucol, Tisseel, yes, the glue, a little bit of that. Then I didn't really like Spongostan, but the one that is like a sponge, it's--
[Dr. Gopi Shah]
Gel foam or something like that.
[Dr. Cristobal Langdon]
Like gel foam. Yes, exactly. Not surgery cells. Surgery cells give a lot of crust. I really like the foam and that's it. No nasal packing. Because in the kids, I try to do everything so in order to not to touch it afterwards. Then just see it a couple of weeks later in the outpatient clinic with the scope and see if they are doing the correct raises and that's it.
Integrating Technology & Compassion in Pediatric Skull Base Surgery
In pediatric skull base surgery, building trust with young patients is essential for success. Children are highly aware and feel less afraid when things are clearly explained in a way they understand. Earning their trust helps them cooperate better during treatment. While parents can sometimes struggle to explain complex procedures, the healthcare team’s compassion and clear communication help bridge the gap.
Integrating advanced technology, such as navigation systems, virtual reality, and 3D printing, is key to improving surgical precision. However, blending this with compassion leads to the best outcomes. While anatomy can be studied, fine surgical skills require practice. Innovative simulation models are being developed to help surgeons refine their techniques, focusing on delicate movements in small spaces. Mastering these tools through compassionate care and practice is crucial for reducing damage during surgery and achieving better results for young patients.
[Dr. Cristobal Langdon]
You really need to win the kid. You really need to be a friend of the kid. You have to achieve that they see you as a friend in order to do all these kinds of things. At least for me, I always try to explain everything because they know if you have kids, you see they realize everything. They are really super intelligent and they are more afraid if you don't talk to them. The parents for sure won't, unless they are really like really super rational parents. It's a little bit of an issue, but if you explain them in their words, why are you doing this?
Why is it helpful for that? I think that that's a good way of approaching these kids. Then, I don't know, I think now it's technology. For me, it's, we are becoming like technicians. At least for me, medicine is art, and then the science is done by the engineers. We are artists with the help of technology, but we need technology. You cannot do good surgery if you don't have technology. Even though you are the best, if you don't have technology, you won't go anywhere. I think that we should embrace technology and use it more. What I have realized is we have a lot of technology, but you don't see a lot of technology in medicine. GPS, you can recognize something from a satellite, but you cannot do a nice navigation system. It's no way. Nowadays, the TV are 8K, 4K was 10 years ago. Yes, it's amazing. Yes, but we are really behind the real technology in medicine. Yes, for sure, virtual reality and the metaverse are the present for me. You should go there and train, train. Now we create a simulation model.
It's a skill simulation model in order to improve your skills more than knowing the anatomy, because the anatomy is in the books. If you do a lot of CT scans or whatever, you will learn anatomy on YouTube or whatever. If you don't have skills, you don't train your skills, that doesn't help you anything. Yes, now we develop one and we are trying to put it on there for everybody to practice. I think it's practice, make the master.
Podcast Contributors
Dr. Cristobal Langdon
Dr. Cristobal Langdon is an academic and private practice rhinologist and skull base surgeon working at Hospital Sant Joan de Déu Barcelona.
Dr. Gopi Shah
Dr. Gopi Shah is a pediatric otolaryngologist and the co-host of BackTable ENT.
Cite This Podcast
BackTable, LLC (Producer). (2022, October 25). Ep. 75 – Technology and 3D Imaging for Endoscopic Skull Base Surgery in Children [Audio podcast]. Retrieved from https://www.backtable.com
Disclaimer: The Materials available on BackTable.com are for informational and educational purposes only and are not a substitute for the professional judgment of a healthcare professional in diagnosing and treating patients. The opinions expressed by participants of the BackTable Podcast belong solely to the participants, and do not necessarily reflect the views of BackTable.
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