QUAD #19: Laryngeal Sensory Reinnervation with Dr. Charles Myer IV

Globalcast MD, along with Cincinnati Children's Hospital, sharing knowledge to improve child health around the globe. Hi, everyone. I'm M. Gody from Cincinnati Children's Hospital Medical Center. In October 2022, Cincinnati Children's hosted the Quad Conference, which was a combination of four conferences. The International Organization for Esophageal Atresia, the Aerodigestive Society Conference, the Cincinnati Children's Airway Course, and the Cincinnati Children's Pediatric Dysphagia series. And in this video, we are going to learn more about laryngeal sensory reinnervation from Dr. Charlie Myer, an ENT surgeon at Cincinnati Children's. We know that swallowing is not just a motor issue, it's also a sensory issue. It's a combined focus of both, and so we need to look at both of those things when we move along. Sensory is also a vagal function. It comes in through the ipsilateral internal branch of the superior laryngeal nerve. Most of the kids that have injuries to the recurrent laryngeal nerve are not high vagal injuries. We understand the etiology, whether it's cardiac procedures or thyroid and patients. A lot of it's iatrogenic, or a lot of it's known, there's a known distal issue. For patients who do not have a known underlying condition, but exhibit signs of higher vagal nerve injury, we also need to evaluate their laryngeal sensation. So, how do we assess laryngeal sensation in those cases? So, how do we test laryngeal sensation? We don't have a tracing that we can easily do. Feast testing, or a FEES plus sensory testing, and that's using a calibrated air pulse by a generator to stimulate the laryngeal adductor reflux. Now, the nice part is if we're looking at people who have CNS insults or high vagal injuries, they may not be able to subjectively tell us if they're getting sensation. When evaluating patients with central nervous system issues or severe injuries to the vagus nerve, an objective assessment becomes crucial because these patients may lack the ability to reliably describe or report any sensations they're experiencing. And so it's an involuntary reflection, we can look at it and just watch for a brief break in respiratory or stimulate a swallow or a laryngeal squeeze is seen on the video down on the right. And sometimes it's challenging to perform this in uncooperative children. So, how do we look at that and how do we correlate that? Dr. Thompson's work in pediatric feast found a correlation to pooled hypopharyngeal secretions to sensory testing thresholds. We can certainly see that there are some other things that we can look at. And I do what I call the poor man's feast where I actually just take my 2.2 mm scope and touch various points around the larynx and see if I elicit a cough or a swallow or a very unhappy child. Hopefully not a emesis. If we're looking at patients who have poor sensation and we are trying to address both the sensory outcomes and the motor outcomes, you want to look at how we can restore the sensation. Could we do a microneurophy between so a sensory branch, in this case, the greater auricular nerve and the internal branch of the superior laryngeal nerve. Dr. Jonathan Aviv described this in 1997 with two patients and he combined this with multiple other procedures. These were patients with central nervous system injuries and strokes who had various motor and sensory deficits in the larynx and had a significant burden with aspiration and aspiration pneumonia. And he did a internal branch of the superior laryngeal nerve reanastomosis with the greater auricular nerve and combined it with a CP myotomy and a mandibular hyoid suspension. When he did this study, he looked at his outcomes for sensation restoration and the improvement in their swallowing function and aspiration. They had good results in the swallowing and aspiration outcomes, but it wasn't until around 6 to 12 months that he saw an improvement in the sensation when he tested with feast. And people describe that it's a tingling sensation in the upper neck or in the earlobe during swallowing. It provides a sensory cue to the patient so they can combine that with their swallow and their therapist to try and work on protecting their airway a bit better. You can follow their progression of the reanastomosis and the return of function or sensation rather through sensory testing with a feast if you have that available. The results you're going to see are really going to happen between 9 to 12 months. And so how do we make that decision to add it in? If we're looking at a sensory deficit, we've got folks with a high degree of aspiration and we're at the end of our outcomes as what we might do to improve their swallow or protect their lungs. Here, we have a 12-year-old patient who had a pilocytic astrocytoma. After undergoing resection, he unfortunately experienced a high vagal injury resulting in a unilateral vocal cord paralysis. Of greater concern was the significant aspiration he developed. It ended up becoming tracheostomy tube and G-tube dependent, despite an injection medialization early on. And so you can see his fees there on the right side of the screen. He has quite a bit of pooling, retained secretions and a poor sensation in the larynx. Down in the larynx, you can touch down there and it doesn't really respond particularly well. What really pushed us to move forward was that he was having early bronchiectatic changes on a CT scan. He was also autistic and was not particularly amenable to the tracheostomy and it was very hard for him to understand why he couldn't eat. But there was a bigger issue for Dr. Myer and his team. The patient was having a lot of issues with lung changes. We performed a combined ansa to recurrent laryngeal nerve and a greater auricular to internal branch of the superior laryngeal nerve anastomosis at the same time. Dr. Myer also did a dual procedure, excising the submandibular glands on both sides and ligated the patient's parotid ducts. And so at this point now several years later, he's tolerating a full oral diet, he's decannulated. He's not had progression of any of his pulmonary changes. No pneumonias and is doing great. You can see on the right side that he has significant improvement in the pooling and significant improvement in the amount of secretions that are retained. When we look for the results, we've got Jonathan Viv's work showed two out of two had improvement in sensation at 12 months and significant improvement. But then Dr. Myer points out that the problem they have is the lack of publications on this matter. There's not any pediatric wards when I talk to the folks who are doing this, we're seeing variable results. In summary, we need to remember that swallowing is a combined neurological function of both motor and sensation. While we often times address the motor piece, we may ignore the sensation. If we know that it's a recurrent laryngeal nerve issue and isolate it, that is great. But if it's not, and they do display signs of poor sensation, we may want to look at reinnervating the sensory component as well. And it's really not quite clear what the long-term results will be of for large populations or when exactly we should do that. But there's an emerging technique that can be useful in salvage cases. Thank you for watching this video. Don't forget to subscribe to the Stay Current MD YouTube channel. Follow our social media channels and download the Stay Current MD app for tons of content in pediatric surgery. Globalcast MD, along with Cincinnati Children's Hospital, sharing knowledge to improve child health around the globe.