Melanie Cole (Host): . Welcome to UAB Med Cast. I'm Melanie Cole and I invite you to listen as we examine the complexity of skull-based surgery from the anterior perspective and the importance of a team approach. This is part two of our two-part series. Joining me is Dr. Kristen Riley. She's a Professor of Brain and Tumor Neurosurgery and Neurosurgical Oncology at UAB Medicine and Dr. Brad Woodworth. He's the James J. Hix Professor of Otolaryngology and Skull-Based Surgery at UAB Medicine. Doctors, I'm so glad to have you join us today. This is a fascinating series here.

So, Dr. Woodworth, I'd like to start with you. Will you explain a little bit about skull-based tumors and the disease processes that you treat?

Brad Woodworth, MD (Guest): Yes. Thank you. Tumors of the anterior skull-base can occur anywhere throughout the ventral skull base. And that includes up in the frontal sinus, which is behind the forehead. And then all the way down to what's called the clivus. And so, that's the general area of the skull base that we're talking about when we talk about anterior skull-based surgery. The most common areas of course are going to be the pituitary type tumors that you're going to get in the sella area, in the central anterior skull-base, but you can also numerous types of tumors that we treat in the ENT world that are attached near the olfactory area where the smell nerves come out of the skull base as well as the ethmoid roof, which is between the eyes.

There's a number of different benign and malignant type pathologies. The most common things that we see from an ENT perspective are things like inverted papillomas, but these also can turn into things called squamous cell carcinomas, which is a malignancy. And the tumors are attached at the skull base. That's where we really joined forces as a multidisciplinary approach to attack these tumors. So, the most common malignant tumors that we see in this area are squamous cell carcinomas, as I mentioned, but also things like malignant melanoma, esthesioneuroblastoma, which is a smell nerve type tumor. And so these tend to be, they tend to go above the skull base and they can actually enter into the dura, which is the covering of the brain. And so this is where that two team approach is really critical to adequately address these tumors.

Kristen Riley, MD (Guest): And I'll add to that and I'm sure we'll get into it. Brad said, it's critical that we have both ENT and neurosurgery and that we work collaboratively from the time the patient is diagnosed. So, we can come up with a surgical plan that's best for the patient. And often is something that we can do entirely endoscopically endonasally, versus 15 years ago, these tumors would be approached with maybe even an open approach through the nose, but absolutely they were most often approached with a bicoronal craniotomy. And so it's fantastic that we can avoid that for many of our patients.

Host: Well, thank you both. So, Dr. Riley, what's different about the lateral and anterior skull-based tumors in terms of difficulty in treatment or challenges that you see and the differences of each?

Dr. Riley: So, when we talk about lateral skull base we often are in the retromastoid area, area of lower cranial nerves. The anterior skull base is a more cephalad and ventral location. Certainly with involvement of cranial nerves, but typically the higher cranial nerves, one through six, whereas the lateral skull base is more six through 12. As these are different locations, the surgeons that operate in these areas are specialized in different ways. So Dr. Walsh, whom you spoke with earlier from ENT is specialized in surgery related to the area of the lower cranial nerves, retromastoid area.

Sort of the law, again, the lateral skull base, whereas Dr. Woodwork's area of expertise is more of the anterior skull base, the endonasal approach. And so these areas are, they're geographically a little bit different. The cranial nerves and blood vessels that are in these areas are different and hence the need for and importance to have a specialized approach with surgeons who, who operate in those areas very commonly.

Dr. Woodworth: I would like to add that also one of the the key issues with doing anterior skull-based approaches are the large holes that are made and the difficulty with repair. And so that's where the technical aspects of our field have really gained traction in the last 15 years is doing good multi-layer type repairs and reconstructions to the skull-base to prevent a postoperative spinal fluid leak.

Host: Well, thank you for that. And along those lines, then Dr. Woodworth, and before we get into some of the really exciting techniques and advances that are in your fields, please tell us about this multidisciplinary approach and given the complexity of many skull-based disorders and with increasingly complex treatment algorithms; who is in charge of patient care? Tell us a little bit about how you all work together.

Dr. Woodworth: Sure. I think we take a co-equal approach to the patients. Say for example, someone with a very large habitus, who's got a spontaneous cerebral spinal fluid leak, for example, and a large anterior cranial fossa encephalocele. So that's going to be a patient who's got idiopathic intracranial hypertension. And so in those cases Dr. Riley and I will perform a lumbar drain at the beginning of a case to assess intracranial hypertension, assist with the cosurgeon in the case at the time of the surgery. But then really afterwards, we're monitoring the intercranial pressure and Dr. Riley really is responsible in that aspect too, if the patient needs a ventricular peritoneal shunt, for example although we only do this about 10 to 15% of the time. It's a very valuable intervention when we identify those patients that require it for a significantly high pressure that are more likely to releak in the future.

When it comes to tumors, you know, we present our cases at a multidisciplinary tumor board. So, radiation oncology and medical oncology are involved as well as other surgical oncologists, neurosurgeons, ENTs and in that scenario where we're formulating a treatment plan for patients with large skull based tumors. And so if you have a cancer that's transdural and we think that chemotherapy might be appropriate first, then they'll get chemotherapy. And then we might re image and determine whether they need an operation or consolidation, chemo, radiation, or even surgery after radiation. And so all those decisions are made on a team like basis. From a standpoint of the collaboration of removing these tumors, that the neat techniques that we have in the last 10 to 15 years is the ability to use scopes through the nose, prevent open incisions, but even in cases where you have tumors that go out to the facial skin, for example, we'll still have my head neck colleagues, for example, may do a maxillectomy at the same time. But then removing the skull base with Dr. Riley. And so even those situations may have other ENTS with different sub-specialties involved. So again, really emphasizing that team approach. Now the endoscopic approach is something very specific to Dr. Riley and myself. I use scopes to approach the tumor and basically skeletonize around the base of the tumor on the skull base.

And then Dr. Riley will come in and in a collaborative fashion, I'll use endoscopes and suctions and she'll use endoscopic scissors and and different grasping tools to remove the skull base through the nose. And we actually can make and repair very large defects here. Recently, you know, four to five centimeters sometimes in these multilayer techniques. We use different types of grafts in the intradural space, but we can also use nasal septal flaps, which is a really useful tool to provide vascularized tissue to repair the skull base.

Other options include endoscopic use of paracranial flaps, which are traditionally used in an open fashion and we've, we use those sometimes when we don't have a nasal septal flap option and we have very large defects. So, I think there's a lot of really nice specialized tools that we have at our disposal that really prevents a lot of postoperative CSF leak and complications that we see.

Kristen Riley, MD (Guest): And just to add in response to the question about how the patients kind of come through our process. So, the nice thing is that we work so closely together. Our clinics and our operating days are coordinated such that if a patient is referred for example, for a pituitary tumor, I have a clinic with an endocrinologist where I see many patients with the pituitary tumors. The majority of those patients that require surgery do not require advanced skull-based closure techniques such as nasal septal flaps, but there is a certain proportion of patients that do. And when that case arises, I coordinate the evaluation with Dr. Woodworth, typically on the same day that I see the patient and and that way the patient does not have to make separate appointments. The referring physicians do not need to make separate appointments. Likewise, when Dr. Woodworth is referred a patient with a skull based encephalocele that needs an evaluation for intracranial hypertension, as he mentioned, that involves placement of a lumbar drain and postoperative evaluation of pressures.

Typically the patient will come in, be referred often by an outside ENT to Dr. Woodward's clinic, he'll coordinate for the patient to see me on the same day. So, I can counsel the patient about the lumbar drain and about the possible need for a shunt. And then our surgical treatment again is coordinated in an efficient manner where typically the patient has the operation with the lumbar drain and repair of encephalocele and then 48 hours later, if their pressures are in a range that they require a shunt, I perform the shunt surgery at the same hospitalization. Again, all in a very coordinated and efficient manner. Our goal is to get the patients into the system and take care of them in this group effort, but not to have outside referring physicians need to make multiple referrals. They get to the door and we'll take them through the process.

Host: Well, I'm so glad that you mentioned outside referrals. So, Dr. Riley, when is it important to refer? What would you like referring physicians to know about communication? And then you can also go into any improved radiologic imaging, anything exciting, anything you want to talk about in your field?

Dr. Riley: So, I would say that, you know, for skull-based tumors, I think that these tumors are often best approached in a multidisciplinary team effort, like we've talked about here on this podcast and really a referral center such as UAB and an academic center is the best place for that to happen. And so any malignancy of the skull base, we would encourage referral here. Benign tumors, such as pituitary tumors, studies have shown that outcomes are best when tumors like pituitary tumors are taken care of at a high volume center and the private practice world while there are many excellent neurosurgeons, if they don't have a referral practice and a multidisciplinary pituitary clinic, they're not going to have access to the same resources that we do here. So, always encourage any pituitary tumor patient to be referred. And as we have alluded to skull-based encephaloceles that require a complex operative approach in order to prevent recurrent encephaloceles in the future, we would always encourage referrals of those and finally tumors that are assumed would require a combined skull-based and craniotomy approach, especially if an outside surgeon has suggested, that's the only way to approach those tumors.

Very often we find that we can approach them endonasally with a much more minimally invasive approach, that's certainly preferable to the patient without compromising anything in the quality of care. So, those are the conditions we would recommend referral. In regards to imaging, we are certainly quite excited about our new intra-operative MRI, which will be coming online in the next month or two.

It's an MRI suite that is within the operating room. So, during a procedure, we can obtain MRI imaging to evaluate extent of resection, if there's anything that we have a question about. That certainly is something that's exciting for us here at UAB. It's not going to be applicable to all anterior cranial endoscopic cases, but certainly there are some that it may provide a significant benefit for.

Host: What an exciting time to be in your field. So, I'd like to give you each a chance for a final thought. So, Dr. Woodworth, tell us a little bit about aftercare, the team approach, as far as after the surgery, where you are involved, where your colleagues are involved and what you would like the listeners to know.

Dr. Woodworth: Yeah, so that's a really important point. So, the care of the skull-based patient is really important from a postoperative standpoint, because the nose and sinuses are really prone to developing sinus infections, obstructive sinusitis when there's operations that create a lot of tissue destruction.

And so, what we find is you know, I see the patients multiple times postoperatively, where we remove packing that's either supporting a skull-based repair or keeping sinuses under good condition or open and patent. Then we initiate numerous types of medical therapies, like, sinus rinses or nasal rinses to improve the overall nasal health of the sinuses afterwards.

These patients, especially post radiation, can get a lot of what's called post radiation crusting. And so the aftercare for any sort of treatment modality is really important to help with overall sinonasal quality of life of these individuals.

Host: And Dr. Riley, last word to you. What does current research indicate for future developments? Are you doing any research that other physicians may not know about, things you're doing at UAB? Kind of wrap it up for us.

Dr. Riley: Sure. So, I think one of the most exciting areas of research is looking for targeted therapies for tumors, looking at molecular markers in tumors that are specific to patients, in individual patients that can help guide their adjuvent care. And UAB is certainly on the cutting edge of that. I think that's quite exciting. We also have a research project looking at familial pituitary tumors. And so that's an exciting area. So, we are thrilled that our patients benefit not only from the expertise from a technical standpoint, from our team approach, from the coordinated care, but also to be part of research and have opportunities for clinical trials and other new advancements in the field.

Host: Thank you both so much. What a fascinating episode this was on the complexity of skull-based surgery from the anterior perspective. Listeners, this was part two of our two part series and a physician can refer a patient to UAB Medicine by calling the mist line at 1-800- UAB-MIST, or you can visit the website at UABmedicine.org/physician.

This concludes this episode of UAB Med Cast. I want to thank you all for joining in and encourage you to check out part one of this series. I'm Melanie Cole. Thanks for listening.