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BackTable / ENT / Article
Parathyroidectomy Surgery Technique: Expert Advice for Optimal Outcomes
Melissa Malena • Updated Aug 1, 2023 • 80 hits
After a diagnosis of parathyroid disease, surgical treatment begins with imaging and is followed by an exploratory procedure and/or focused excision. The size, type and position of adenoma determines the ideal imaging modality. During parathyroidectomy surgery, careful nerve and parathyroid hormone monitoring are required by the surgeon and anesthesiologist. In cases without a definitively overactive gland, surgeons must use their best clinical judgements to remove the offending gland or glands. As thyroid structure varies in patients, the location of glands also varies and must be accounted for in parathyroidectomy surgery. When parathyroid carcinoma is suspected, fine needle aspiration is recommended for biopsy. Although difficult to visibly differentiate, parathyroid carcinoma can be thoroughly pathologically diagnosed and requires timely, aggressive treatment.
This podcast features excerpts from the BackTable ENT Podcast. We’ve provided the highlight reel in this article, and you can listen to the full podcast below.
The BackTable ENT Brief
• Four-dimensional (4D) CAT scans are favored for parathyroid disease imaging due to their ability to differentiate between parathyroid adenomas, lymph nodes, and the thyroid gland. This imaging technique involves thinly sliced CAT scans with arterial and venous contrast phases.
• The surgical procedure varies based on whether it's a focused parathyroidectomy surgery or a four-gland exploration. Nerve monitoring is crucial in every case. If a four-gland exploration is performed, the surgeon finds all four parathyroids before touching any of them to prevent unnecessary removals.
• Parathyroid gland locations can be unpredictable due to embryological development. The lower parathyroids, which have a longer descent path, are often found in the mediastinum, carotid sheath, or inside the thyroid gland.
• Due to similarities in imaging results, parathyroid carcinoma can initially be mistaken for thyroid cancer. An FNA biopsy, correctly directed with washouts and high serum calcium and parathyroid hormone levels can help establish the correct diagnosis.
Table of Contents
(1) Preferred Imaging Modalities for Parathyroid Disease
(2) Parathyroidectomy Surgery Technique
(3) Locating Hidden Parathyroid Glands
(4) Differentiating Parathyroid Carcinoma
Preferred Imaging Modalities for Parathyroid Disease
Different imaging techniques can be used in diagnosing and treating parathyroid disease. Expert head and neck surgical oncologist Dr. Goldenberg prefers the four-dimensional (4D) CAT scan, a thinly sliced CAT scan with arterial and venous contrast phases. This allows differentiation between parathyroid adenomas, lymph nodes, and the thyroid gland. Despite the fact that normal parathyroids, being the size of a grain of rice, are difficult to detect, a parathyroid adenoma - around the size of a raisin - can be detected. However, each imaging modality has its pros and cons and it is up to physician discretion to employ the best modality for each unique case.
[Dr. Dipan Desai]
Then how do you go about elucidating what type of disease they have, whether it's an adenoma or four gland disease in terms of imaging studies or any other evaluation prior to surgery?
[Dr. David Goldenberg]
There are studies that say that actually when, and this is counterintuitive, that if people have multigland disease that their parathyroid hormone is actually lower. All of my patients will get at least one imaging modality if they've not had it done beforehand. If I'm convinced that the patient has primary hyperparathyroidism and their localization imaging or images do not localize anything, then that's the assumption that we go on that they have multi-gland disease.
[Dr. Dipan Desai]
What are the imaging studies that you prefer?
[Dr. David Goldenberg]
Because of the way patients are referred to us from the outside and they come into a tertiary medical center, oftentimes the patient comes with something already done. Sometimes it's adequate and sometimes it's not. If I'm the person working the patient up, I go with a four-dimensional CAT scan. I've been doing this for a while and this has evolved over time. First, I did Ultrasounds in the office and then I was doing CT scans and now, I believe that the four-dimensional CAT scan is the most accurate for my practice. I don't typically do double scans as proof of the disease. There are those who do, if they say that if you have two concurrent modalities that show this, then you know you have your diagnosis. I personally don't do this. I go with the imaging in the lab.
[Dr. Ashley Agan]
Can you elaborate on what a 4D CT scan is?
[Dr. David Goldenberg]
A 4D CT scan is a lot less cool than it sounds. When I first heard of it, I thought it would be spinning and holograms. There's none of that. It's basically a thinly sliced CAT scan with multiple phases of arterial and venous contrast and some nifty software which allows you to differentiate between parathyroid adenomas, lymph nodes, the thyroid gland. It also gives you some really nifty imaging of the arterial blood supply to the parathyroids and that also helps find adenomas.
We have to remember that the size of a normal parathyroid is the size of a grain of rice and there is no imaging modality to date that can see a normal parathyroid. That being said, a parathyroid adenoma can be maybe the size of a raisin. They can be bigger too, but oftentimes they're not all that impressive when you get them out. It's nice to wear loops because they look really big to you when you're taking them out, but they really are not that big.
[Dr. Dipan Desai]
Can you talk a little bit about the pros and cons of the alternative imaging modalities, either in-office Ultrasound or SPECT CT scans?
[Dr. David Goldenberg]
Sure. Ultrasound is wonderful. As long as the adenoma is at the threshold or above the threshold of detection, size-wise, then it's great. You see a hypoechoic nodule. If it's an inferior parathyroid, typically you'll see it, it's extra thyroidal, it's hypoechoic. Upper parathyroid adenomas are easier to-- You can see, again, extra thyroidal hypoechoic, and then you see a thyroid tissue above it on the longitudinal scan, great. The problem is the two enemies of Ultrasound are air and bone.
If it's below the clavicles, if it's an elderly person, if it's below the manubrium, if it's behind the airway, you're not going to see it. A SPECT scan, PA SPECT scan is injection of technetium and has a different washout time. Nowadays most people are doing a SPECT CT scan fused where you have functional anatomic data at the same time superimposed one upon the other. The technetium stays behind in the adenoma when it washes out of the thyroid gland and the CAT scan shows you anatomically where it is and you put them together and you get a nice little area in either orange or blue that's illuminated very nicely.
It will not see very small adenomas, and it also is a little weaker in flat adenomas. This is anecdotal, this is what I've seen when I was doing, if the adenoma is flattened against the back of the thyroid gland, sometimes it won't be seen. Like I said, the four-dimensional CAT scan has been great. If someone comes in with a scan and it's non localizing, I certainly will get them another scan in our institution. It's important if you're doing this kind of surgery that you feel comfortable reading these scans yourself, and I do, I do get radiology's input, but they're quite a few times where they've said there's nothing there and I thought there was, and in the end, surgery proves whether you're right or wrong.
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Parathyroidectomy Surgery Technique
According to Dr. Goldenberg, a significant amount of complex decision-making is involved in preoperative scanning. When the scan doesn't localize a lesion but the symptoms suggest a problem, an exploratory surgery may be performed. Dr. Goldenberg utilizes intraoperative rapid parathyroid hormone (PTH) testing to gauge surgical success. Patients can undergo a targeted parathyroidectomy surgery or a four gland exploratory procedure, with the end goal of excising the problematic gland. Throughout the procedure, physicians must prioritize implementing nerve monitoring, careful handling of the parathyroid to protect its blood supply, and nuanced decision-making when determining which glands to remove.
[Dr. Ashley Agan]
Yes. I imagine the straightforward cases come in, they have hypercalcemia, they have hyperparathyroidism, they have a scan that has a localizing lesion where you're like, "Ah, there it is right there." Then you talk to the patient about surgery. What about the patients who are not as clear cut? What if the scan is not showing anything, but your labs are really suggesting that there is something, how do you approach that?
[Dr. David Goldenberg]
That's a great question. If I'm convinced and the patient is on board with having a surgery, I will explain to them what the issue is and it didn't localize, but I am convinced that there is a problem here and it can be fixed surgically. Then typically we'll do an exploration and evaluate all four parathyroids and decide which one or ones are the offending parathyroids in that person's case.
[Dr. Ashley Agan]
If the first scan doesn't show anything, do you at least get two scans that are not showing anything before you go to surgery? Or will you ever have one scan and then talk about it and do four gland exploration just based on that? Let's say it's a 4D CT, it's the best that you can do.
[Dr. David Goldenberg]
If a person comes in, if they don't have a 4D CT scan and nothing is localized, they're getting a 4D scan in our institution before we move forward. If the patient comes in and they've tried everything and it's been done someplace and I read the scans and the radiologist read the scans and we're convinced there is nothing, I typically won't get them a third. If they have a SPECT CT and a 4D CT, I'm not going to get them an Ultrasound. They'll probably go straight to surgery. It really depends on how comfortable I am with the pre-preoperative localization imaging. It's not-- We will go over those scans even from the outside and sometimes I don't agree and I say, "You know what? It's not convincing, but I think there's something on the left lower one." That's the way I'll start it." The patient has to be aware that this may end with a four-gland exploration.
[Dr. Dipan Desai]
Once you've decided to take the patient to the operating room, can you talk a little bit about what are your cutoffs for considering the surgery of success and if you use intraop-parathyroid hormone testing to help guide you?
[Dr. David Goldenberg]
If the parathyroid is like a chip shot and it's big and you know where it is and you take it out, that's great, but I routinely use intraoperative rapid PTH and conventional wisdom is if you have a drop in 50%, then it's considered successful. That's supposedly 10 minutes. I typically wait 15 just because sometimes there's some manipulation of the gland and I just want to make sure that the drop is a drop.
There are cases where the patient comes in with parathyroid hormone, which is not all that high, and it's even borderline high and 50% would take it very, very low. That's again, where clinical judgment comes in. If I'm sure that I got the offending parathyroid or parathyroids and the hormone has dropped, but it's not exactly 50%. There have been times where I've said, okay, that's it. We got what we needed to do.
[Dr. Ashley Agan]
Can you talk a little bit about the actual surgical approach and technique?
[Dr. David Goldenberg]
Sure. If this is a first-time parathyroid and we know where it is, I approach this much like I do a thyroidectomy. We make a very small incision about the level of a coker incision, so two fingerbreadths above the clavicles in the midline. It's about an inch, a little more than an inch and a half. We move the strap muscles aside, medialize the thyroid gland. If I know where it is and it's lower parathyroid, then sometimes you don't have to take the middle thyroid vein, but oftentimes you do to adequately mobilize the thyroid gland and then we find the parathyroid.
If I'm doing a focus parathyroidectomy, then we just remove it and wait and measure the parathyroid hormone. If it's an upper parathyroid, it's very important to remember that the upper parathyroid is in close proximity to the recurrent laryngeal nerve and you have to be careful. Sometimes it's not uncommon to have it right adjacent to the nerve. If I'm doing a four-gland exploration, it's a little bit different. Their conventional wisdom says that you find all four parathyroids before you touch any of them.
The reason you do that is, you're saying, "Oh, I'm sure it's this one." Then you find one on the other side that's even bigger and then you find yourself leaving the OR with the patient missing two unnecessarily. I typically do not use frozen section as a test for the parathyroid itself but there are times where a patient has a grape like multinodular goiter with these little nodules falling off adjacent to and you don't know if you have a little piece of parathyroid or a little piece of thyroid gland. In those cases, the frozen section is helpful. In my practice if I do a focused parathyroidectomy, the patient's closed up and they go home the same day. If I do an exploration, I treat it like a thyroidectomy and I keep those patients for 23 hours.
[Dr. Ashley Agan]
You're identifying the recurrent laryngeal nerve when you are addressing a superior parathyroid adenoma then if it's inferior, you don't necessarily need to go look for it?
[Dr. David Goldenberg]
You don't necessarily. I typically do. I think it's really healthy for the residents to feel comfortable doing that. We do find it every time. I don't really know. It is the gold standard during thyroid surgery. I don't know that I've read it particularly for parathyroid surgery. We typically find it. My point was that the upper parathyroid is there, that's right where the nerve crosses or the nerves just come to, but lower parathyroid, you can do a lower parathyroidectomy and not encounter the nerve at all because it's variable.
[Dr. Dipan Desai]
Are you using nerve monitoring for all of these cases?
[Dr. David Goldenberg]
Every time. Every case, every time.
[Dr. Ashley Agan]
Yes. It makes sense. Any pearls as far as identifying parathyroid glands without damaging their blood supply, especially with the normal ones being so tiny.
[Dr. David Goldenberg]
Yes, that is a great point and I'm sure Dipan will concur that loops are helpful. You know that they get their blood supply from the inferior thyroid artery, typically both of them. Not always, but typically, and it's gentle handling of tissue. These are tiny little glands. Blunt dissection is done gently. One of the points that people have been taught for as long as they've been doing parathyroid surgery is the fact that you want to keep this bloodless because blood stains the parathyroid. Parathyroids have a different color than any of the surrounding fat.
If you look at it closely, they say it's ochre, it's more brown than fat and it's really important to be able to see these nuances so the entire dissection should be meticulous and bloodless. When you pick up a parathyroid, you never grab the gland itself. You always grab the fat cap if you're grabbing it all. If you can do it without grabbing, that's wonderful. You can see the blood supply often, and you really have to-- as you alluded to, you have to be very careful because there's no point in leaving a dead parathyroid behind because you took out the tiny arterial supply.
[Dr. Dipan Desai]
It's funny you mentioned that. I feel like I've heard a lot of different descriptions for the color of a parathyroid, but almost always food related, either salmon colored or nutmeg and I find that of variable use but super subtle sometimes. Then once you've identified potentially you're offending glands or if you're doing a four gland hyperplasia case, all four glands. Can you talk us through your decision making on how much to remove and which glands you remove and what you choose to leave behind?
[Dr. David Goldenberg]
Well, sometimes it's really hard to tell. I have taken biopsies of each gland and asked if they were hypercellular. I've looked at them closely. There are those who say to leave the lower one because the blood supply is more robust. If you're going to leave, leave a lower one. You have to look at all four of them and evaluate which ones look the most abnormal, and you start with that. If both lower ones are frankly abnormal, they're the first ones to go. If I can save a lower one because the upper ones are abnormal or more abnormal looking then I will do that. It really is nuanced. I wish I had some real guidance there. There needs to be a little bit of clinical decision making.
Locating Hidden Parathyroid Glands
It is important to understand the embryology of the parathyroid glands to locate them in surgical procedures. According to Dr. Goldenberg, lower parathyroids are more likely to be misplaced due to their longer descent path, often found in the mediastinum, carotid sheath, or inside the thyroid gland. The upper parathyroids can also be found in similar locations. When a gland can't be found, even after extensive exploration, the last resort is a possible hemithyroidectomy. However, Dr. Goldenberg warns against hasty conclusions, highlighting the importance of meticulous dissection and thorough visual examination, often with the aid of a pathologist, to ensure the correct identification and removal of the parathyroid glands.
[Dr. Dipan Desai]
Okay. Obviously sometimes these cases can be tricky where you go in thinking you have a single localized adenoma, or you start doing your four gland exploration and one of the parathyroid didn't read your wonderful textbook and is hiding. Can you talk us through some of the steps and places you go looking for a parathyroid that's not where it's supposed to be?
[Dr. David Goldenberg]
Sure. Someone once told me if it was easy, it wouldn't be fun. As you well know the pan-parathyroid surgery can be incredibly quick and easy and simple. There are times it can be very frustrating because where is it? It is paramount that the parathyroid surgeon understands the embryology of the parathyroid glands because that's the key to where the missing gland is if something is missing. I think that's what you're asking, correct?
[Dr. Dipan Desai]
Yes.
[Dr. David Goldenberg]
The lower parathyroids have a longer descent and therefore they're more apt to get lost. That's just the way it is in medicine or an anatomy embryology and the most common place for a lost lower parathyroid is in the mediastinum together with the thymus and other places that they can be, would be, in the carotid sheath and even inside the thyroid gland. The upper parathyroid, and I have seen those get lost. They also are in the carotid sheath. They're usually retropharyngeal or retroesophageal.
I'm not talking about case reports where they're in the submandibular gland or some really really strange place. Depending which parathyroid is missing, if you're looking for them and every patient is, should be consented for, even if it's a focused parathyroidectomy, every patient is consented for a parathyroid exploration and possible hemithyroidectomy, which is the last place you look, if you are missing a gland and you've looked in the mediastinum, you've dissected the mediastinum you've looked in the carotid sheaths and you're still missing a gland, then we've all seen intra thyroidal parathyroid glands. Most of the intra thyroidal parathyroid glands are in the capsule. They're not really deep in the substance and sometimes you can actually see it, but sometimes it's actually in the substance of the gland.
[Dr. Ashley Agan]
How common is it for it to be in the gland?
[Dr. David Goldenberg]
It's not common. More often you'll see it inside the capsule, but outside the gland like inside the thyroid capsule, but not really in the substance but that also is not all that common.
[Dr. Ashley Agan]
Yes. If you're not finding it you should not be too quick to say, oh, it's probably in the thyroid.
[Dr. David Goldenberg]
No, you have to. If it's a lower, you really do need to dissect the upper mediastinum like you would a central compartment lymph node dissection, and you pull up the thymus like a magician pulling scarves out of a hat and that's the most common place that you would find it. I have seen them in the sheath and I've seen uppers behind the esophagus as well. It happens, the more you do, the more often you're going to see these things and I guess those are the ones that take a little bit more clinical acumen.
[Dr. Dipan Desai]
When you're dissecting out either the central neck compartment or looking in your thyroid gland, are you relying on your pathologist or is it still a visual examination?
[Dr. David Goldenberg]
Oh, I will absolutely rely on my pathologist at that point in time. That's a perfect example of when you need the help of the pathologist. Now Dipan, I'm sure you know this because you do this all the time. When you see a parathyroid adenoma, there it is, it looks like a little piece of liver. It has a certain look to it. Here we go again with food, but sometimes it's hard to tell. For example, Hashimoto's thyroiditis is incredibly common.
Hashimoto's thyroiditis comes with a lot of these little round lymph nodes and sometimes it can be confusing. It's not out of the realm of possibility that your patient has Hashimoto's thyroiditis and they have hyperparathyroidism. Then sometimes you are looking at a whole bunch of little grapes. and you have to make sure that this is in fact, the parathyroid. You just didn't remove an inflamed lymph node. Yes, we definitely would rely on the pathologist if I'm not sure or if I want to differentiate thyroid from parathyroid. Absolutely.
Differentiating Parathyroid Carcinoma
Although rare, parathyroid carcinoma is a possible and serious diagnosis. Patients with this disease often present with significantly abnormal calcium and parathyroid hormone levels, potentially leading to severe health problems. Parathyroid carcinoma might be initially mistaken for thyroid cancer due to similar imaging results, making preoperative diagnosis challenging. This condition necessitates a serious treatment approach, similar to managing other aggressive cancers, which can include surgical procedures like thyroid removal or neck dissection. Dr. Goldenberg recommends fine-needle aspiration (FNA) biopsy in diagnosing these cases, underscoring the importance of correct direction and washouts in the procedure.
[Dr. Dipan Desai]
Obviously, the worst case scenario is, as you mentioned, super rare but a parathyroid carcinoma. I know that diagnosis can be very difficult. Have you ever encountered that, and what are some of the signs intraoperatively that you might be dealing with something that's not a normal parathyroid adenoma?
[Dr. David Goldenberg]
Well. Before we go intra-operatively, preoperatively patients who have parathyroid carcinoma are more apt to come with incredibly abnormal calcium and parathyroid hormone. Their calcium can be dangerously high, and that's the first thing that can bring them to medical attention. They've been in the emergency room, they've gotten their fluids and no one knows why. Oftentimes parathyroid hormone will be incredibly high. If primary hyperparathyroidism you'll have parathyroid hormone in the hundreds, parathyroid carcinoma, you could have in the 1000s. They will often come with a mass in the neck.
While a patient with primary hyperparathyroidism their physical exam is completely unremarkable unless you want to count aches and pains, and kidney stones. They may have a lump in the neck, a mass in the neck, a fixed thyroid, something that doesn't seem right. Those patients should be treated like any other patient with an aggressive cancer, more like a squam than with thyroid cancer in my mind, because parathyroid carcinoma, as rare as it is, can be pretty nasty. Those patients will probably lose at least half the thyroid, perhaps a neck dissection depending on what is found on preoperative imaging and what you find intraoperatively. Obviously, like any other oncological case, anything that it is stuck to, needs to go. Unfortunately a rare entity.
[Dr. Ashley Agan]:
Those patients probably get a preoperative FNA since they have a mass that's big enough to biopsy.
[Dr. David Goldenberg]
They do, or they can. I've only seen this in a handful of cases in my career. That's how uncommon it really is. Most of the patients-- trying to think back, because it really is not that common. I guess some of them were originally thought to have thyroid cancer because that's what it looked like on the imaging. F and A directed correctly with washouts could probably do the diagnosis for you.
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. Dipan Desai
Dr. Dipan Desai is a practicing otolaryngologst and head and neck surgeon with ENT Associates in St. Petersburg, Florida.
Dr. Ashley Agan
Dr. Ashley Agan is an otolaryngologist in Dallas, TX.
Cite This Podcast
BackTable, LLC (Producer). (2023, January 17). Ep. 85 – Surgical Management of Parathyroid Disease [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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