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Melanie Cole, MS (Host): Welcome to AHN Med Talks, an informative resource for physicians across various specialties as we delve into the latest medical insights and best practices, ensuring you stay at the forefront of your field. I'm Melanie Cole. And today, we're highlighting endoscopic Skull Base Surgery at AHN: When to Refer and What to Expect. Joining me is Dr. Jason Crossley. He's a rhinologist and skull base surgeon in the Division of Otolaryngology, Head and Neck Surgery at AHN.

Dr. Crossley, thank you so much for joining us today. When people and even other providers hear skull base surgery, they often think of highly invasive procedures. For listeners who may not fully appreciate how much this field has evolved, give us a sense of what modern skull base surgery looks like today and how endoscopic approaches have really changed the landscape for you.

Dr. Jason Crossley: Well, thanks so much for having me. It's a great point. Skull base surgery traditionally used to be very a morbid invasive surgery. Not so long ago, the standard approach for anterior cranial base lesions used to involve a lot of cuts on the face, disfiguring scars, and a long time in the hospital. This is different now.

Many lesions can be approached purely through the nose, which involves no external incisions. It involves a shorter recovery time, because we don't have to do a very invasive maneuver, such as retraction of the brain parenchyma. And many times, it can be a shorter stay, as long as a few days or less in the hospital.

In terms of the question, when to refer, it's usually when there's concern for a problem along the skull base. And these can arise with a variety of symptoms. I think the major things to be aware of would be things that do not have an explanation or if there's evidence of a solid tumor on cross-sectional imaging.

So, you may find a radiology report that indicates some level of asymmetry along the skull base or the sinus or nasal cavities or if there's, for example, clear or watery drainage from the nose. This would be evidence of a cerebrospinal fluid leak. These are both problems that could be addressed from endoscopic skull base surgery.

Melanie Cole, MS: Well, thank you for that, Dr. Crossley. So, you've built a truly multidisciplinary skull base program at AHN. Many providers from different specialties. Talk about the philosophy behind that team-based model and why collaboration is so essential in these cases. Walk us through the makeup of the skull base team. What unique role neurosurgeons, ENT surgeons, skull base surgeons, neuroradiologists, I mean, you've got a lot of people, and what they bring to the table that's so unique?

Dr. Jason Crossley: So, a lot of skull base surgery is made challenging by the anatomical structures along this area. So, we are working around important things like the internal carotid arteries and nerves that come out of the bottom of the skull. And so, accessing them can be quite difficult, and it can often be at the interface of the domain of expertise of different surgeons.

And so, the majority of these cases will involve a partnership between an otolaryngologist like myself and a neurosurgeon, and we work together where my domain of expertise may be primarily along the sinuses and the nose, and their domain of expertise may be operations on the brain and the central nervous system. And where that interface meets at the skull base is where we both have a lot of overlap and can use that to have multiple eyes on the same problem and kind of make some decisions together that borrows from our area of expertise.

I think a real big strength of what we have here at Allegheny Health Network is a large group of folks from different subspecialties who are all very passionate and invested at addressing these problems. And so, although most surgeries will involve an otolaryngologist and a neurosurgeon, there are a lot of folks behind the scenes making sure that the patients get all the right stuff done. And specifically, these are our neuroradiologists, who are radiologists who have undergone training in a radiology residency and additional training in a fellowship in head and neck radiology and neuroradiology. And so, they're specifically focusing on images along the skull base and building a repertoire of expertise to detect even subtle asymmetries to make sure we're identifying where the problem is and how we can fix it.

Along with this, we have interventional neuroradiologists. So, these are radiologists who have undergone additional training that can help us identify, for example, vascular lesions or vascular structures and help us control some of the major risks that are associated with skull base surgery, which would be injury to the internal carotid artery. And having a team that's ready to take care of some of these rare but potentially devastating complications with minimal morbidity is super important to make sure all patients can get really the best outcome that they can have from very, very challenging problems.

Melanie Cole, MS: So, how has endoscopic surgery improved outcomes and recovery for patients that have these kind of sinonasal tumors compared with the more traditional approaches?

Dr. Jason Crossley: So, number one for common problems such as, pituitary tumors or pituitary adenomas, we're now able to do a more thorough removal of these tumors by improved visualization of the sella and parasellar areas, which is where the pituitary gland normally is. And we're able to see further out to the side and access further out to the side than the prior paradigm, which was a microscopic approach, which really limited the lateral visualization and reach.

And the consequence of this is that patients are having to undergo typically one surgery rather than multiple revision surgeries due to residual tumor for less common pathology. So beyond just the sella where the pituitary gland lives, we're now able to remove these tumors from an endoscopic approach alone. And what this can mean is no external scars. It can mean a much smoother recovery, because we are doing less retraction of intracranial contents, which can prolong recovery and essentially getting out of the hospital much faster. We're able to preserve a lot of function by not having to traverse any cranial nerves or anything like this.

And we're also able to address cerebrospinal fluid leaks. And this was a major limitation, when the endoscopic approach was first developed because we're making now cuts along the bottom of the cranial cavity, and gravity can lead cerebrospinal fluid to leak out this way. And this was a major challenge, and we now have techniques such as the nasoseptal flap, which is taking tissue from the inside of the nose to reconstruct holes at the bottom of the skull base and significantly reduce our risk of postoperative cerebrospinal fluid leaks.

And so, this used to be a major barrier to advancement of these techniques. But now, we know that we're able to get equal or lower rates of complications such as cerebrospinal fluid leaks with a faster discharge from the hospital and a more thorough surgery, potentially requiring less surgery down the road.

Melanie Cole, MS: Yes, that's so important. Now, when you are evaluating a patient, Dr. Crossley, what does a comprehensive workup typically involve? Speak a little bit about the importance of nasal endoscopy, cranial nerve examination, and advanced imaging that's available both intraoperatively and what you use in the clinical examination.

Dr. Jason Crossley: So in the office with me, patients will all undergo nasal endoscopy. This is a rigid camera that is passed through the nose to inspect the sinuses and to evaluate for pathology. Important things that I'll be looking at is making sure there's not an infection that could complicate work along the skull base and be a reason for delaying that. I'll also be able to evaluate the use of local tissue in the nose that'll be used for reconstruction. And then, also other sinus or nasal problems. There can be things like fungus balls in the nose or other benign tumors that we want to make sure we address and are not surprises on the day of an endoscopic skull base surgery.

Part of the clinical exam always includes a close examination of the cranial nerves. Many of these tumors may present with a subtle, double vision. And so, I'll always do a very thorough cranial nerve exam because we want to make sure we identify problems here that could potentially improve after surgery, or we want to keep an eye on things that will help make patients feel better when we address these cranial neuropathies.

A discussion in the office is always important about the patient's values. So, many of these tumors may have problems with cranial neuropathy, but also there can be more subtle problems. And so, olfaction or the sense of smell is a major area of concern when we go through the nose. And a discussion about how the endoscopic endonasal approach may affect their olfaction, because it may, is very important because of the quality of life implications that this has.

In some cases, we can modify our techniques specifically with the use of the intranasal tissue flaps that we use for reconstruction in a way that will oftentimes preserve olfaction, which is still very hard to predict, but it's important to have a good understanding with the patient about the pros and cons of these techniques and these approaches based on their quality of life impact that the presenting problem may be causing them, but certainly as well as the recovery from the surgery.

Melanie Cole, MS: This is so interesting. And Dr. Crossley, resident education is clearly an important component of this program. How are resident physicians incorporated into these highly specialized cases? And what do you hope they take away, these trainees, from participating in skull base surgery, not just technically, but philosophically in terms of patient care and that multidisciplinary approach that you spoke of?

Dr. Jason Crossley: I'm so fortunate to be able to work with residents here in our Allegheny Health Network residency program. We have an otolaryngology head and neck surgery residency. And also, I frequently work with the neurosurgical residents. These folks are major contributors to our team. I believe that having an additional set of eyes from the resident physicians improves patient care. They can oftentimes detect problems that are not at the forefront of my mind. And so, as a patient, it's a major advantage to be able to get another set of eyes on you and help make sure that all the problems are identified that are pertinent to the presenting problem.

And in terms of what I hope them to get out of it is that skull base problems are relatively rare, but being able to see this in training and identify them can be very, very important. Because many of these, particularly the malignant neoplasms, are best identified early and early identification can often lead to the best sort of outcomes. So, exposure to this in their training is important to me for when they go out into careers that may or may not include skull base surgery, they feel confident in identifying these. They also have the opportunity to learn during the surgery with graduated autonomy in the operating room as well. And in doing so, that they develop the skills to be able to address some of these problems on their own.

Melanie Cole, MS: Dr. Crossley, there's also an exciting research component through collaboration with Carnegie Mellon University. Tell us about some of the innovation or clinical research efforts underway and that potential for participation in clinical research.

Dr. Jason Crossley: So, we are very lucky to have collaborators in the neurosurgical division who have pioneered getting an innovation lab off the ground. And I'm really fortunate to be able to participate with them. And as part of that, they've developed relationships with professors of engineering over at Carnegie Mellon that are focused on development of devices that may be able to help with identification and accuracy of EEG or electroencephalography.

And so, a current area of research that we're working on collaboratively is testing the safety and efficacy of a device that may be placed in the sphenoid sinus, which is a sinus that we frequently access for surgery along the skull base, to have more accurate tracing of intracranial electrical waves.

And so, currently in collaboration with the neurosurgeons and the folks over at Carnegie Mellon University, we are identifying some patients who have undergone an endoscopic sinus surgery with me as potential candidates to participate in the development of these devices, which could improve the detection of things like Parkinson's disease, epilepsy, and others by improving the sensitivity of the EEG recordings.

Melanie Cole, MS: And Dr. Crossley, where do you see emerging technologies, whether AI, imaging advances, surgical navigation, data science, shaping the future of skull base surgery over the next decade or so?

Dr. Jason Crossley: I think in the operating room, we're currently using stereotactic navigation, which has been in use for decades for confirmation of visual identification of critical structures. Currently, there are investigations underway to try to improve the real-time use of these, for example, with visual overlay of structures that we see on camera to see what's beneath the structures that we can see specifically, when we look with the nasal endoscopy in the operating room.

I think there's always going to be a role for more primitive technology, such as cutting instruments, coagulation instruments. However, I think the area for probably the biggest area of approval is real-time structure identification in the operating room. So far, there's nothing that's been developed that's been shown to make things safer or faster. And this is an important threshold for any medical device to reach because without reaching these criteria, we're just adding cost without improving outcomes. And so making sure that all of these advancements undergo appropriate stringent reviews is super important. And so, we only use things that we know are really going to help in terms of outcomes. But certainly, I think using computer vision type technology to help with structure identification could potentially help make operations faster and safer.

Melanie Cole, MS: You've given us so much to think about and so much great information. It's really an exciting time in your field, Dr. Crossley. And for referring physicians listening, when should they consider referring a patient to a multidisciplinary skull base program? And as you think about the key takeaways that you would like them to know about your program and communication with the referring physician, what would you like them to know?

Dr. Jason Crossley: I think anytime there's concern for a problem along the skull base, and these problems would include a cerebrospinal fluid leak, a tumor, and these could include a pituitary or other tumors, or any neurological symptom of the cranial nerves that hasn't been explained would be a reason to refer. Problems within the sinus and nasal cavity would be a reason to refer as well, because many of these benefit from a multidisciplinary collaboration as well.

Having a team with several subspecialists who are passionate about taking care of this is very important, and having the experience of working together is very important, I think, to improve outcomes because these problems are quite rare. And so, seeing folks at a multidisciplinary center like ours, we think is probably the best in terms of patients getting their best outcomes. And so, it's very, very important that patients with rare problems like this go to a center where there's a group of doctors that are all passionate about taking care of patients like this. And so, anytime there's really any suspicion for a skull base or sinonasal tumor, we'd be more than happy to take a good look at them.

In terms of referral networks, the neurosurgical department receives these and I do it and other partners in my division as well. And so, whether they go in first to see the neurosurgeon or see one of us from the otolaryngology head and neck surgery division, we'll usually correspond with each other directly to help make sure we're doing the right thing.

Melanie Cole, MS: Thank you so much, Dr. Crossley, for joining us today. And to learn more or to refer your patient to Dr. Crossley, please call 844-MD-REFER or visit findcare.ahn.org. Thank you so much for listening to this edition of AHN Med Talks with the Allegheny Health Network. I'm Melanie Cole.