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BackTable / ENT / Article
Thyroid Radiofrequency Ablation: A Practical Guide for Otolaryngologists
Iman Iqbal • Updated Aug 27, 2024 • 34 hits
Thyroid nodules are abnormal growths of thyroid tissue that form lumps within the thyroid gland. While some of these nodules remain benign and asymptomatic, others may grow large enough to cause discomfort or pose a risk of malignancy, necessitating medical intervention. Clinically significant thyroid nodules affect a significant portion of the population, often necessitating intervention to resolve symptoms.
Radiofrequency ablation (RFA) is a minimally invasive treatment option that offers an alternative to traditional surgical methods for certain thyroid nodules. By utilizing precise, real-time ultrasound guidance, RFA allows for the targeted destruction of nodular tissue, alleviating symptoms and reducing nodule size with minimal risk of complications.
This article, featuring excerpts from the BackTable ENT Podcast, discusses the application of RFA in thyroid nodule management, including the criteria for patient selection, procedural techniques, and potential outcomes, as explained by otolaryngologist Dr. David Goldenberg. You can listen to the full podcast below.
The BackTable ENT Brief
• Imaging studies, particularly ultrasound, are the primary diagnostic tools for assessing thyroid nodules. Additional tests, such as thyroid function tests and fine needle aspiration (FNA), are essential for determining the nature of the nodules.
• RFA is a viable alternative to surgery for treating thyroid nodules, particularly benign ones that are causing symptoms like compressive effects on swallowing, or cosmetic concerns.
• RFA is generally used for nodules that are cystic or non-cystic and larger than two centimeters.
• Contraindications for RFA include large malignant nodules, unsuitable nodule positions, pregnancy, active infections, and severe bleeding disorders.
• RFA is performed in a clinical setting with local anesthesia, utilizing continuous ultrasound guidance and the "moving shot technique" to ensure thorough ablation without damaging surrounding structures.
• Post-operative care is straightforward, with patients typically managing pain with NSAIDs and using ice to reduce swelling. Follow-up ultrasounds are scheduled at 6 and 12 months.
• RFA aims for a reduction in nodule size of 50% to 80% within one year. Re-ablation is possible for large or complex nodules if symptoms persist.
• Complications from RFA are similar to thyroid surgery but occur at a lower rate, with potential risks including vocal cord paralysis and infection. However, severe complications like thyroid hematomas are rarely reported with RFA.
Table of Contents
(1) Evaluating Thyroid Nodules: When Is RFA the Right Treatment?
(2) Evaluating Candidates for Thyroid RFA: Procedure Risks & Contraindications
(3) Thyroid Radiofrequency Ablation Procedure Technique
(4) Post-Operative Care for Thyroid RFA Patients: Pain Management, Follow-Up, & Re-ablation
(5) Potential Complications of Thyroid Ablation
Evaluating Thyroid Nodules: When Is RFA the Right Treatment?
Imaging studies, particularly ultrasound, are the primary diagnostic tool for assessing thyroid nodules. Thyroid function tests, especially the TSH level, are also commonly performed. Other laboratory tests, such as auto-antibody testing for inflammatory conditions, might also be conducted. In some cases, fine needle aspiration (FNA) or core biopsies are necessary to determine if the nature of the nodule is benign or malignant. FNA is a highly specific and sensitive diagnostic tool that informs whether the subsequent treatment approach should be surgical or through radiofrequency ablation (RFA).
Traditionally, benign nodules that are asymptomatic might be monitored without intervention, while symptomatic or potentially malignant nodules require surgical intervention. However, RFA has emerged as a viable option for certain types of thyroid nodules. Typically, RFA is used for benign nodules, either cystic or non-cystic, including those causing goiter, autonomously functioning thyroid lesions, or those that are symptomatic and growing. These symptoms might include compressive effects on swallowing, breathing, or comfort, or cosmetic concerns. In addition, for RFA to be considered, nodules generally need to be larger than two centimeters.
While it is possible to treat multiple nodules with RFA, the procedure typically focuses on the nodule causing the most significant issue. Each RFA session takes approximately 40 to 45 minutes, and most patients handle the treatment well.
RFA can be performed by a variety of specialists, including otolaryngologists, endocrine surgeons, and endocrinologists. The key requirement is that the clinician is well-trained in the procedure and highly skilled in interventional ultrasound, as the procedure relies on continuous ultrasonic guidance to ensure precise targeting and safety.
[Dr. David Goldenberg]
Before performing any intervention on thyroid nodules, there needs to be some comprehensive workup to ensure that patients are safe and appropriate for whatever procedure we're doing. Typically, we talk about medical history and physical exam just like any other illness or any other syndrome or any other issue. We want to make sure of pre-existing medical conditions, medications, allergies, et cetera.
Oftentimes, we get imaging studies when it comes to thyroid. Typically, that is an ultrasound, which is the imaging modality of choice. Oftentimes, we'll get thyroid function tests at the very least a TSH level. Many times, patients are sent to us with these values already in their chart. Patients may have had a final aspiration biopsy or a core biopsy. Sometimes we need to send them for that. Other laboratory tests, in some cases, auto-antibody testing for inflammatory conditions, patient's evaluation perhaps for anesthesia, and obviously, the discussion of the risks and benefits.
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FNA is paramount for evaluating whether the patient has benign or malignant disease, and that's typically why we get it. It's both highly specific and sensitive, and it's the cornerstone of interventional treatment of thyroid nodules, whether it be surgery or radiofrequency ablation.
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RFA is typically used for benign thyroid nodules, that's first of all, either cystic or non-cystic, sometimes for goitrous lesions, for autonomously functioning thyroid lesions, and nodules that are growing and symptomatic.
Symptomatic means they're causing compressive symptoms to swallowing, to comfort, to breathing, or they are a cosmetic concern for the patient. There is a potential application for micropapillary thyroid cancers which is being evaluated as we speak and is used in other parts of the world. That's where RFA fits in. Oftentimes, patients will come specifically asking because they do not want to have surgical intervention but the nodule is bothering them in some way.
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We typically say larger than two centimeters. If they exhibit an increase in size, I have to be convinced that their compressive symptoms are being caused by this. As you well know, patients sometimes will have compressive or what they call compressive symptoms or cough or issues that may be attributable to other things including something as benign as laryngeal reflux, but in their mind, their thyroid nodule is causing it. When you look at the nodule, it's half a centimeter, it's obviously not causing it.
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Evaluating Candidates for Thyroid RFA: Procedure Risks & Contraindications
When selecting patients for RFA of thyroid nodules, it's crucial to assess both the patient's expectations and the nodule's characteristics. Patients must understand that RFA does not provide immediate shrinkage; the nodule may initially swell before the body clears the necrotic tissue.
Characteristics like large coarse calcifications or potential malignancy may complicate the procedure, and patients must be cooperative and capable of staying still during the procedure due to the needle's proximity to sensitive areas like the recurrent laryngeal nerve. Uncooperative patients, those with cognitive impairments, or individuals with allergies to anesthesia are typically not suitable candidates. Other contraindications for RFA include pregnancy, active infection, and severe bleeding disorders. Additionally, high BMI, C-spine issues, and nodules in challenging locations such as near the sternum require careful consideration, but they don't automatically disqualify patients if the procedure can be performed safely.
Moreover, clinicians are starting to consider RFA for micropapillary thyroid carcinomas in some countries and clinical trials in the U.S., especially when the nodule is small and located in a manageable position. The rationale for using RFA on microcarcinomas is aligned with the active surveillance strategy often used for thyroid cancer patients. While RFA has been explored for recurrent thyroid cancers abroad, particularly in parathyroid lesions, it remains a cautious option due to concerns about incomplete treatment of recurrence and the potential for other cancerous areas.
[Dr. Gopi Shah]
I'm glad you talked about risk, and I wanted to next talk about patient selection. Are there certain nodule characteristics where you're like, "Hmm, this may not be a good candidate because the nodule's in the danger triangle, or I have to worry about the recurrent laryngeal nerve?" Tell me some of that when you have to think about the nodule and if this is a good candidate for radiofrequency ablation.
[Dr. David Goldenberg]
It's really important, the patient selection, just like any other procedure. It's really important that, first and foremost, that the patient wants to have this done. Usually they seek me out to have this done. I have to evaluate them first to make sure that they're appropriate candidates from what they have and what their expectations are. I explain to them, for instance, that this does not shrink overnight. As a matter of fact, it may swell up a little bit the next day from the work that I've done, and that the body has to evacuate the necrotic tissue for this to shrink.
Patient expectations, I guess there are certain ultrasonic characteristics which may make this more difficult. That would be patients who have large coarse calcifications, patients who I suspect that the lesion is malignant. Sometimes you'll have patients who they're looking for an answer and sometimes it's not really the answer they want to hear. Uncooperative patients, for instance, it's very important to make sure that you have a patient who is not cognitively impaired, someone who will cooperate. Cooperation means lying still and notifying me if they need to swallow because there's a large needle in their neck.
Actually, we give them a little squeaky ball if they need to swallow. Sometimes you'll have patients who it's very difficult for them to comply with. Obviously, patients who have allergies or reactions to anesthesia, those would not be favorable patients.
[Dr. Gopi Shah]
What about patients with high BMI or a bigger neck? Any concerns with like, "Do you need the neck extended," or if they have C-spine issues, anything like that may make you say, "I don't know if this is going to be a good procedure for you?"
[Dr. David Goldenberg]
Absolutely. That's a great point. I have done patients with issues with their C-spine and I've done morbidly obese patients as well. The discussion is had up front. Just like before I do thyroid surgery, I always check a patient's ability to hyperextend and also to tilt their neck because sometimes when a nodule is close to the clavicle, all you need them to do is turn their head in the opposite direction to bring it out. I do have patients hyperextended like thyroid surgery, and when they're awake, it's a lot less tolerable than when we have them doing so for a thyroidectomy when they're asleep.
Morbid obesity, I've not found these to be issues with patients. Typically, I can always use a probe that has a greater depth. It has not been an issue.
[Dr. Gopi Shah]
In terms of the nodules that are by the clavicle or near the sternum, is there any contraindication or does it just make it more difficult? Are you still able to get those that are, right at the sternal notch? What do you need to make that nodule work with RFA?
[Dr. David Goldenberg]
They're evaluated. Remember, all these patients, before they are found to be appropriate for RFA, they all have ultrasounds, which I view personally, and they all have at least one benign biopsy. That's really important. If I'm comfortable that we can do this, then it's fine. I've had patients who came to me who have a retrosternal goiter, most of it in the mediastinum, and I tell them, "This is not appropriate for you."
Sometimes people understand and they just undergo a surgical procedure with me and they get the result that they need. There are sometimes patients who they'll go find someone else because they don't like the answer they hear.
[Dr. Gopi Shah]
You mentioned large calcifications, you mentioned malignancy, is there ever a role for radiofrequency ablation? You said potentially for the microcarcinomas?
[Dr. David Goldenberg]
Yes. It's a great question, Gopi. The contraindications for RFA would be large malignant nodules, unsuitable nodule characteristics like we discussed, whether it's too close to a blood vessel or a nerve and it's unsuitable. Pregnancy, I don't think that we should be doing this on pregnant patients. It's certainly usually not an urgent issue. As you know, obviously, thyroid nodules will fluctuate during pregnancy, and after pregnancy, and lactation, et cetera.
Actually, active infection, which is not something I've seen, severe bleeding disorders, and uncooperative patients or patients who have cognitive impairment of some kind. Those would be your contraindications, but there is a role, a growing role for microcarcinomas. This is done routinely in Brazil and Korea and there's a clinical trial going on here in the United States.
I would feel comfortable doing a microcarcinoma if it was in the right place and in the right patient. For that, they would totally destroy the nodule. The rationale being that there are patients who are undergoing active surveillance. Most of my thyroid cancer patients, I continue to watch anyway. These are patients who would just be watched very closely with serial ultrasound.
[Dr. Gopi Shah]
Some of your recurrences. You've already done surgery, for example, papillary thyroid cancer, and now we have a recurrent nodule. Any role for recurrent RFA and recurrent lesions?
[Dr. David Goldenberg]
Again, abroad, there are people who are doing that. There are people who are doing parathyroid lesions. I personally have not done those and I guess I would personally-- I would look at recurrent cancer very skeptically given the fact that if it's a recurrence, is that the only area? I'm not really sure. It's not something that I would feel comfortable doing at this point in time.
Thyroid Radiofrequency Ablation Procedure Technique
Thyroid RFA is typically performed in a clinical setting, where patients remain awake under local anesthesia, supplemented by a cervical block and mild sedation. The procedure begins with a dose of Ativan to relax the patient, and then a local anesthetic like lidocaine is applied to the thyroid isthmus. A small incision is made, and using ultrasound guidance, a spinal needle administers lidocaine between the strap muscles and the thyroid capsule to anesthetize the area. The RFA probe is then inserted through this incision, and heat from the probe necrotizes the nodule tissue by raising temperatures to 60-100 degrees Celsius. The "moving shot technique" is employed, where the probe is constantly moved to ensure thorough ablation of the nodule and to avoid obscuring the ultrasound image.
During the procedure, real-time ultrasound visualization is crucial for precise navigation and ensuring safety. The ultrasound probe remains on the nodule throughout the process, providing continuous feedback on the ablation's progress. The RFA probe is periodically activated for one to two seconds as it ablates sections of the nodule from medial and deep to lateral and superficial positions. The procedure avoids critical areas like the carotid artery and the "danger triangle" where the recurrent laryngeal nerve is located, to minimize risk to the patient. Once ablation is complete, the operator verifies coverage by switching to a lateral ultrasound view, ensuring all necessary parts of the nodule have been addressed without affecting sensitive structures.
[Dr. David Goldenberg]
We do this in the clinic. The patient receives local anesthesia, regional anesthesia, cervical block, and some sedation, but it's done completely awake in clinic. I ask that they have a driver and they go home right afterwards. Yes, it's very convenient for the patients.
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First and foremost, the patient is given 0.5 or 1 milligram of Ativan prior to the procedure. The procedure itself is not painful, but I do say that it is intense because I am leaning right over their face and their neck while they're awake with a big needle in their neck and an ultrasound probe in the other hand. What we do is we give a local anesthetic in the midline over the isthmus of the thyroid with lidocaine. Then we make a small stab incision with an 11 blade.
Then under ultrasonic guidance, using a spinal needle, we insert the needle in between the strap muscles above and the capsule of the thyroid gland below, and then we use the lidocaine to hydro-dissect and basically anesthetize the capsule of the thyroid gland. Once that's done, the radiofrequency ablation probe is inserted through the stab incision through the isthmus of the thyroid. From there, it's placed inside the nodule that we're going to ablate.
The heat that's produced by the electric tip causes tissue necrosis and fibrosis, introducing a high-frequency alternating current, raises the temperature to 60 to 100 degrees Celsius. We use something called the moving shot technique. We work from medial and deep to lateral and superficial, and we constantly move the radiofrequency ablation probe. I say that because radiofrequency ablation is not a new technology. For the decades, it's been used for liver tumors and for pain management. Originally, when it was first used, they would place the radiofrequency probe in the middle of whatever lesion they were going to ablate and turn on the heat and just leave it there and let it heat from the inside out. That's not what we do with thyroid.
Here, what we do is we keep on moving the needle to make sure that we get all of or as much of the nodule ablated as possible, but also so that we are able to continue to see what it looks like and the ablation does not obscure the rest of the nodule. This way we get a really good ablation, and then it will scar down and the body will remove a lot of this necrotic tissue.
…
The local anesthetic, where we put it just under the skin, we don't need that, but once I've made the stab incision where the local is placed, which is usually in the middle of the neck over the isthmus of the thyroid, tiny little incision, then a spinal needle is used under ultrasound visualization in between the strap muscles above and the thyroid capsule below it. Then the lidocaine is injected in between those two layers, and this is how we anesthetize the capsule of the thyroid gland.
[Dr. Gopi Shah]
Then you said when you put the RFA needle in, your ultrasound probe is visualizing the nodule the whole time so that you can see the needle?
[Dr. David Goldenberg]
At all times.
[Dr. Gopi Shah]
At all times, and you're going and moving the needle as you ablate from medial and deep to lateral and superficial. As you do that, are you holding it for like one or two seconds-
[Dr. David Goldenberg]
Yes, yes.
[Dr. Gopi Shah]
-and then taking incremental-- Is there a pedal and then you're holding it down the whole time, or do you have to start, stop, start, stop?
[Dr. David Goldenberg]
You have to start, stop. It's under direct visualization. You can actually see as the changes in the thyroid at the tip of the needle, sometimes it bubbles and pops and you'll see this white trail. In addition, you're able to look at the impedance on the machine. If the baseline impedance for where you are in the nodule suddenly jumps, what that means is that area has already been ablated and we move on.
…
[Dr. Gopi Shah]
How do you know when you've ablated enough? Are you going to see, "Okay, 50% of it looks like it's shrunk now and we're good?" How do you make that call?
[Dr. David Goldenberg]
There's obvious sonographic features that guide the operator in real time. Microbubbling, as I explained, and the increase in the general impedance as the tissue stiffens, which is an indication of coagulative necrosis. What we're trying to do is approach the tissue in subunits from the deepest to the most superficial so that we don't obscure ourselves. What you see is these white tracks where you have ablated. It's very, very obvious. Once you've finished ablating, then I will go from a transverse view to a lateral view to make sure that I have hit all the levels.
Now, there are important areas that you want to avoid. For instance, at all times, you'll see the carotid artery, and at all times, you'll see the danger triangle, which is the area where the recurrent laryngeal nerve is tethered to the trachea, close to the posterior medial aspect of the thyroid gland. In those areas, I typically do not ablate because of the risk to the patient.
Post-Operative Care for Thyroid RFA Patients: Pain Management, Follow-Up, & Re-ablation
The post-operative care for patients undergoing RFA of thyroid nodules is straightforward. The procedure itself takes about 45 minutes, and patients typically do not require antibiotics since it is a sterile procedure. Pain management is usually accomplished with non-steroidal anti-inflammatory drugs (NSAIDs), and ice can be applied to the neck to reduce any swelling, which is common. In terms of follow-up, patients are usually checked on within the week after the procedure. Ultrasounds are scheduled at 6 and 12 months to monitor the reduction in nodule size.
The goal of RFA is to achieve a reduction in nodule size of 50% to 80% within a year, but it is important for patients to understand that this reduction does not happen immediately. In cases where nodules were very large initially and only a 50% reduction is achieved, some symptoms, such as dysphagia or compressive symptoms may persist. Re-ablation is an option in these scenarios and has been performed on patients with particularly large or complex nodules. In some cases, patients may choose to undergo surgery if they feel it is necessary, but generally, re-ablation does not preclude additional RFA treatments.
[Dr. Gopi Shah]
They come in, it's about 45 minutes. What are your post-op instructions? You had mentioned that sometimes they can swell back up a little, their neck can have a little swelling afterwards. Do they have to do warm compresses? Is there any reason for antibiotics?
[Dr. David Goldenberg]
No, we typically don't treat. It's a clean, sterile procedure. I do not give antibiotics. Their pain, I typically will put a little bit of ice on the neck. Their pain is controlled typically with non-steroidal anti-inflammatory drugs. I've not had any patients who have had any need for anything further than that.
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We typically check up on them that week to see how they're doing. When I first started, I was getting ultrasounds at 3, 6, and 12 months. Now I get them at 6 and 12 months. Since I've been doing this, and until recently, I'm the only person in the Commonwealth of Pennsylvania doing it, I have people traveling from very far away. I don't want it to be a hardship for them to have to travel back for me to say, "Hey, how are you doing? I'll feel your neck."
We typically do it at 6 and 12 months. If they come from far, I'm agreeable to them getting an ultrasound in their home location as long as I can get my hands on the actual images, and then we assess it. Typically, we like to see a reduction of 50% to 80% at a year. It's very important that the patients, again, understand this does not occur overnight.
[Dr. Gopi Shah]
A good result is 50% to 80% at a year. Let's say the size has gone down 50%, but it was really big in the beginning, and maybe they still have some dysphagia or compressive symptoms. How often do you have to go back and re-ablate or are there risks associated with that?
[Dr. David Goldenberg]
No, you can ablate more than once. I've done it on, I believe, two occasions. One is someone who had a huge partially cystic, partially solid nodule, and a lot of it reaccumulated in both of these. It just had a lot of islands that were secreting. I had one patient who after one time opted for surgery and I did that. It does not preclude you from doing it again if necessary. It's usually not necessary. When it is necessary, it's in patients who have really huge nodules. When I started patient selection, I tried to be very, very careful when I was doing patients with really large nodules. Those are the patients who need to have it done a second time typically.
Potential Complications of Thyroid Ablation
Complications from RFA of thyroid nodules are generally similar to those of thyroid surgery but occur at a lower rate. Some potential complications include vocal cord paralysis, bleeding, infection, and damage to surrounding structures in the neck. Vocal cord paralysis is a concern due to the proximity of the recurrent laryngeal nerve, and patients are counseled about the potential for voice injury. There's also a possibility of Horner’s syndrome.
However, certain complications common in thyroid surgery, such as thyroid hematomas, are rarely, if ever, reported with RFA. In thyroid surgery, a hematoma in the central compartment can be life-threatening due to its proximity to the airway; but, this is not a concern with RFA as the thyroid remains in situ. Additionally, there have been no reports of severe hemorrhaging, significant hematomas, or thyroid storms related to RFA. Thus, while counseling patients, it’s essential to emphasize that while the risk profile is similar to that of surgery, the actual incidence of complications with RFA is notably lower.
[Dr. Gopi Shah]
In terms of complications from RFA, we talked about the danger triangle and having heat close to the recurrent laryngeal nerve. When you counsel patients on a potential voice injury, or recurrent laryngeal nerve injury, how do you counsel them? What other potential complications do you counsel the patient on?
[Dr. David Goldenberg]
Complications for RFA are similar to those for thyroid surgery, but they occur at a lower rate. We're actually doing a study right now, which hopefully will be ready this year, looking at complication rates and comparisons. Obviously, you have vocal cord paralysis, bleeding, infection, and damage to surrounding structures in the neck. There are reports of Horner syndrome.
Like I said, the complication rates are lower in the literature and there are some complications, for instance, that I don't know of any descriptions of a thyroid hematoma. A thyroid hematoma after thyroidectomy or a hematoma in the central compartment after thyroidectomy is life-threatening because you have a large bleed in an area near the airway. I don't know that this really occurs with RFA. The thyroid is still in situ and I've not seen or read about any severe hemorrhaging or hematomas. I have not read about thyroid storms, but I would just say that they have similar complications, but to a lower degree.
Podcast Contributors
Dr. David Goldenberg
Dr. David Goldenberg is a professor and the chair of the department of otolaryngology - head and neck surgery at Penn State in Hershey, Pennsylvania.
Dr. Gopi Shah
Dr. Gopi Shah is a pediatric otolaryngologist and the co-host of BackTable ENT.
Cite This Podcast
BackTable, LLC (Producer). (2023, October 31). Ep. 139 – Radiofrequency Ablation: Modern Management of Thyroid Nodules [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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