Table of Contents
- Case Overview
- Statement of Consent
With both improvement in preoperative parathyroid tumor identification and the use of intraoperative parathyroid hormone (PTH) assay, minimally invasive parathyroidectomy (MIP) is now performed more frequently in patients with primary hyperparathyroidism (pHPT) compared both historically and with cervical exploration. Still, many institutions are not familiar with performing MIP under regional or local anesthesia. We present such an operation under local cervical block anesthesia.
About 85% of patients with primary hyperparathyroidism (pHPT) harbor a single adenoma and are cured by resection of the single lesion. The remaining patients display double adenomas (3–5%) or four-gland hyperplasia (10–15%).1 Focused minimally invasive parathyroidectomy (MIP) is now feasible under regional or local anesthesia. MIP is performed after preoperative parathyroid localization usually with high-quality sestamibi scans, ultrasonography, or four-dimensional parathyroid computed tomography (4DCT) scans. A rapid intraoperative parathyroid hormone (PTH) assay is employed to confirm an adequate resection.
The patient is a 60-year-old female with biochemically unequivocal primary hyperparathyroidism. She was being evaluated for a thyroid nodule and on work up for that was found to have elevated blood and urine calcium levels. The patient's symptoms include frank osteoporosis with a T-score of -2.6 in the femoral neck and -2.3 in the lumbar spine. She has no history of nephrolithiasis or overt neurocognitive symptoms. There are no complaints of hoarseness, difficulty swallowing, or difficulty breathing. She has no history of radiation to the neck or face.
The biochemical evaluation demonstrates a total serum calcium of 10.7 mg/dl (reference range 8.8–10.2 mg/dl), elevated PTH levels of 76–81 pg/ml (reference range 10–65 pg/ml), and hypercalciuria with a 24h urine calcium of 438 mg/24h. Preoperative imaging with both ultrasound and sestamibi with single-photon emission computed tomography (SPECT) suggested a left lower parathyroid lesion.
The single most accurate imaging modality for preoperative planning in patients with pHPT is the parathyroid 4DCT. The parathyroid 4DCT is similar to CT angiography.2 The term is derived from three-dimensional CT scanning with an added dimension referring to the changes in perfusion of contrast over time. Exquisitely-detailed, multiplanar images are obtained that accentuate the differences in the perfusion characteristics of hyperfunctioning parathyroid glands (eg, rapid uptake and washout) to those of normal parathyroid glands and other structures in the neck. Compared with sestamibi with SPECT, 4DCT is significantly less expensive but associated with higher exposure to ionizing radiation and thus should be used cautiously in children and young adults.3 Moreover, due to the use of intravenous contrast, it should be avoided in patients with renal insufficiency as well as in patients with a concomitant, well-differentiated thyroid carcinoma.
The most commonly used modality remains sestamibi with SPECT, which generates three-dimensional localization. A major limitation of sestamibi scans is the coexistence of thyroid nodules or other metabolically active tissues (eg. lymph nodes, thyroid nodules, and metastatic thyroid cancer) that can mimic parathyroid adenomas, thereby causing false-positive results. Sestamibi with SPECT does not provide detailed anatomical depiction and can only detect double adenomas and multiglandular hyperplasia in 25–45% of cases.2
We perform ultrasound routinely because it is effective, noninvasive, and inexpensive. The limitations include both operator dependency and inability to image mediastinal adenomas because it is limited to the neck. The normal parathyroid gland is generally too small to be visualized sonographically, whereas the parathyroid enlargement seen in pHPT is often identified as a homogeneously hypoechoic extrathyroidal ovoid mass. Parathyroid adenomas are typically vascular, and an arterial branch can often be followed to the superior or inferior pole of the lesion. By itself, ultrasound has approximately a 50–75% true-positive rate with generally better rates for larger glands.2
This patient was referred after positive imaging by the endocrinologist (both the ultrasound and sestamibi with SPECT suggested a left lower parathyroid lesion). In such a scenario, I would not subject the patient to a 4DCT scan.
The natural history of untreated pHPT has been studied in detail and involves deteriorating bone and renal, neurocognitive, and cardiovascular functions, which are all beyond the scope of the article.4
There are no other curative treatment for pHPT except surgery. However, lowering the serum calcium temporarily can be done pharmacologically.4
The indications for MIP are the same as those for traditional cervical exploration: symptomatic patients or those with asymptomatic pHPT fulfilling the criteria established by the most recent National Institutes of Health (NIH) consensus meeting.4 In addition, there are now significant data to support more liberal use of surgery because the disease has been associated with several “nonclassical” morbidities, some of which seem to improve postoperatively.4 These include neurocognitive impairments and cardiovascular abnormalities.
Unilateral surgery for pHPT was first advocated in 1975, and the side to be explored was chosen based on palpation, esophageal imaging, venography, or arteriography.5 The success of MIP has been confirmed by evidence of cure and complication rates that are at least as good as those achieved by conventional bilateral exploration.6 The complication rate of MIP is similar or lower compared with the standard cervical approach.7 Recurrent laryngeal nerve injury may occur in 0.5–1.0% of cases.6 The risk of permanent hypoparathyroidism is absent if a single gland is explored and removed, but there is always a concern in patients undergoing subtotal parathyroidectomy for multiglandular disease.
The current patient demonstrated a biochemical cure of her pHPT and had no complications.
I prefer local and regional block anesthesia with monitored anesthesia care (MAC) as opposed to general anesthesia using either an endotracheal tube (ETT) or laryngeal mask airway (LMA). The regional block is performed by the surgeon in the operating room, and intravenous supplementation is directed by the anesthesiologist. In most patients, 1% lidocaine containing 1:100,000 epinephrine is used and added during the operation as required. Care is taken to aspirate before delivering the anesthetic to avoid intravascular administration. The total cumulative volume of lidocaine administered is typically 18–25 ml. Intravenous sedation is used to minimize patient anxiety while maintaining an awake, conscious patient who can phonate.1
Regional anesthesia avoids complications associated with general anesthesia, such as nausea and vomiting. Avoiding endotracheal intubation is beneficial because it has been reported to cause vocal cord changes in up to 5% of patients.6, 8 Furthermore, exploring a conscious patient permits intraoperative assessment of the superior and recurrent laryngeal nerve functions because the patient can vocalize during the procedure.
No preoperative imaging modality will replace the need for a well-trained, thoughtful parathyroid surgeon.9 Surgeons performing MIP must understand the embryology and anatomy of the parathyroid glands. The embryonic development and descent into the cervical neck of the parathyroid glands lead to a highly-variable anatomy. Ectopic parathyroid tissue is commonly encountered within the thyroid, thymus, mediastinum, carotid sheath, and tracheoesophageal groove. Undescended glands can be located along the carotid bifurcation or along the larynx.
The MIP technique is individualized after the parathyroid adenoma has been localized. Typically, a 2.5–3.5-cm abbreviated Kocher incision is made, followed by the creation of limited subplatysmal flaps and the opening of the median raphe. The thyroid gland is then mobilized anteromedially. The parathyroid adenoma is then identified, aided by the preoperative imaging. It is important to handle the parathyroid adenoma gently to avoid rupture of its capsule, which may spill parathyroid tumor cells. If the parathyroid gland is grasped, it is preferable to handle the parathyroid by the fat pad often extending around the gland or its end-arterial blood supply. The end-arterial blood supply is ligated using clips or silk ties. Prior to excision of the parathyroid adenoma, the recurrent laryngeal nerve is protected. Parathyroid surgery is a meticulous procedure and operative experience correlates with rates of recurrence and persistence as well as complications.1 The procedure is guided by intraoperative PTH measurements.
Intraoperative PTH measurement is employed routinely. The circulating half-life of PTH is 3.5–4.0 minutes, and thus PTH levels are obtained prior to surgery and at 5 and 10 minutes after tumor extraction. PTH levels should decline (>50%) within 5 or 10 minutes after the removal of the hyperfunctioning parathyroid adenoma as the remaining normal parathyroid glands are the only source of PTH. If this is the case, the patient requires no additional exploration. Failure of the peripheral venous PTH level to adequately decline suggests remaining hyperfunctioning parathyroid tissue, and additional surgery is indicated under either regional or general anesthesia. In addition to being a valuable adjunct to confirming the completeness of parathyroid resection, the rapid PTH assay is a useful adjunct to other aspects in the treatment of pHPT. We routinely perform ex vivo fine needle aspirations of tissue excised during parathyroid surgery to measure PTH. A positive aspirate will demonstrate PTH levels greater than 1,000 pg/ml. This has eliminated the need for frozen section analysis in most cases. Although we rely heavily on the intraoperative PTH assay, it does not replace clinical judgment, and the assay should be interpreted in this context.1
The pathology revealed an enlarged (1.8 cm) and cellular parathyroid gland weighing 507 mg (normal about 30–40 mg). At the postoperative visit eight days following surgery, the patient’s total serum calcium was normal at 9.5 mg/dl (reference range 8.8–10.2 mg/dl), and she had a normal PTH level of 32 pg/ml (reference range 10–65 pg/ml). Her vocal cord function was normal as well.
No special equipment was used.
Nothing to disclose.
The patient referred to in this video article has given his informed consent to be filmed and is aware that information and images will be published online.
- Carling T, Udelsman R. Focused approach to parathyroidectomy. World J Surg. 2008;32(7):1512-1517. doi:10.1007/s00268-008-9567-z.
- Starker LF, Mahajan A, Björklund P, Sze G, Udelsman R, Carling T. 4D parathyroid CT as the initial localization study for patients with de novo primary hyperparathyroidism. Ann Surg Oncol. 2011;18(6):1723-1728. doi:10.1245/s10434-010-1507-0.
- Mahajan A, Starker LF, Ghita M, Udelsman R, Brink JA, Carling T. Parathyroid four-dimensional computed tomography: evaluation of radiation dose exposure during preoperative localization of parathyroid tumors in primary hyperparathyroidism. World J Surg. 2012;36(6):1335-1339. doi:10.1007/s00268-011-1365-3.
- Bilezikian JP, Brandi ML, Eastell R, et al. Guidelines for the management of asymptomatic primary hyperparathyroidism: summary statement from the Fourth International Workshop. J Clin Endocrinol Metab. 2014;99(10):3561-3569. doi:10.1210/jc.2014-1413.
- Roth SI, Wang CA, Potts JT Jr. The team approach to primary hyperparathyroidism. Hum Pathol. 1975;6(6):645-648. doi:10.1016/S0046-8177(75)80073-6.
- Udelsman R, Lin Z, Donovan P. The superiority of minimally invasive parathyroidectomy based on 1650 consecutive patients with primary hyperparathyroidism. Ann Surg. 2011;253(3):585-591. doi:10.1097/SLA.0b013e318208fed9.
- Bergenfelz A, Lindblom P, Tibblin S, Westerdahl J. Unilateral versus bilateral neck exploration for primary hyperparathyroidism: a prospective randomized controlled trial. Ann Surg. 2002;236(5):543-551. doi:10.1097/01.SLA.0000032949.36504.C3.
- Kark AE, Kissin MW, Auerbach R, Meikle M. Voice changes after thyroidectomy: role of the external laryngeal nerve. Br J Med (Clin Res Ed). 1984;289(6456):1412-1415. doi:10.1136/bmj.289.6456.1412.
- Stålberg P, Carling T. Familial parathyroid tumors: diagnosis and management. World J Surg. 2009;33(11):2234-2243. doi:10.1007/s00268-009-9924-6.
Cite this article
Carling T. Minimally invasive parathyroidectomy under local cervical block anesthesia for primary hyperparathyroidism and parathyroid adenoma. J Med Insight. 2022;2022(225). doi:10.24296/jomi/225.
Table of Contents
- Patient Positioning
- Inject Anesthesia for Local Cervical Block
- Kocher Incision
- Use a 2.5–3.5-cm abbreviated Kocher incision
- Mobilize thyroid medially
- Ligate the middle thyroid vein
- Retract the thyroid medially
- Identify the left inferior parathyroid adenoma
- Handle the parathyroid adenoma gently to avoid rupture of the capsule
- Use the silk tie to elevate the parathyroid adenoma out of the tracheoesophageal groove
- Perform ex vivo aspiration and PTH measurement of the left inferior parathyroid adenoma
- Measure PTH in the systemic circulation, preoperatively, at the time of excision, and every 5 minutes thereafter
- Close Strap Muscles at Midline
- Close Platysma Muscles
- Close Dermis with 5-0 Prolene
- Apply Dermabond and Steri-Strips
- Remove Suture
So this is a 60-year-old female who was being worked up for a possible thyroid nodule and, during that workup, was found only to have a 7 millimeter thyroid nodule, but the biochemical workup showed that she was hyperglycemic. So she was then proven to have biochemically unequivocal primary hyperparathyroidism with a calcium ranging between 10.7 and 10.9, with the intact PTH of 81. She had preoperative imaging at an outside institution that showed possible lesion in the left lower position - both with sestamibi as you can see here. This is a sestamibi where I would expect. Again this is an imaging study we don't use as much anymore, since we have the four dimensional parathyroid CT scan. But if the patient is referred, we do already positive imaging. I wouldn't necessarily repeat the imaging. So this shows subtraction images and remnant of thyroid tissue but clear uptake of technetium-99 in the left lower position, consistent with a left lower parathyroid adenoma.
So during operation, which was again done under local cervical block anesthesia, we easily identified this lesion, preserved the esophagus as well as the recurrent laryngeal nerve and resected the tumor. Her intraoperative PTH level started out at the baseline of 93, and at time zero it was 65, and at five minutes, it was 36, proving that the patient was cured. She will spend about an hour in the recovery room, and assuming that she has no nausea or any other issues, she'll be able to go home today - and then follow-up next week as an outpatient.
So - so we're doing a minimally invasive parathyroidectomy, so the patient is a little bit in a semi-Fowler position with a pressure bag underneath the back just to give a little bit of a head extension, and then we got the peripheral IV that is used for giving sedation as well as drawing the intraoperative PTH levels. And then an ether screen just to keep a little bit of air on the - over the face so she's not claustrophobic as well as glasses just to protect her eyes. Alright, we'll take a marking pen. Alright, so this is the sternal notch. This is the clavicle.
So we like to make the incision small but in a natural skin crease, so we use an abbreviated Kocher incision. And then for the cervical block, we use anterior border of the sternocleidomastoid muscle, injecting about 2 cc of 1% lidocaine to 1 to 1 - with 1 to 100,000 of epinephrine as well as Erb's point, where the transverse cervical nerves come out. So we'll take two locals. Are you guys ready for us?
Alright, it's a little pinch and a burn, and when we inject, we inject about 20 milliliters all together. And it's important to aspirate when you do the lateral injection to ensure that you're not injecting lidocaine or epinephrine in - into the vascular system whether it's the external jugular vein or the carotid artery or internal jugular vein. Alright, so we're starting.
Just fix that lower light for us a little bit, Jose. So now we're opening the platysma.
This is the first muscle layer, opening up horizontally. Don't go too deep there. Alright, we'll take double skins. So pull that up in the air - pickups, fine tonsil. I'm just extending the opening of the platysma a little bit on each side. Then the next step is going to be op - opening up the strap muscles.
So here's the midline between the strap muscles, so we're just going to extend that incision. Okay, grab the muscle to your side. I'll grab mine. And then go south. Okay, that's good. I'll take a thyroid retractor. You take that muscle towards you. You stay high up there - just tilt the table a little bit towards me now. That's good. Okay, and then follow that south. Alright, you can take that out. That's okay - don't worry about it. It's on the - it's on the back there, right? So we're just following the strap muscles south there. We'll take a Babcock now. Just shine here a little bit more. Alright, so here is the thyroid gland.
Here is the strap muscles, so we're going to stay right underneath that muscle - and I'm pulling the thyroid as - while she's peeling that muscle off the thyroid gland. Just pull a little harder there. Just pull a little harder there - don't give up on that hand. Okay, and then we're going to go inferiorly and do the same thing. Just follow that south. We'll take a squirt coming in. Just open that up a little more. Okay. Pop that off the thyroid. Let's push into it. Okay, so now I'm retracting the thyroid medially towards me. You have the - the common carotid artery and the internal jugular vein right here. I'm gently bringing that, and you're relax on that hand. Then, if you pick something up here... So know that the recurrent laryngeal nerve is going to be deeper here, and sitting right here is the left lower parathyroid tumor. So follow that all the way up. So keep that retractor deep in. So here I'm retracting the thyroid gland towards me, and sitting right below the thyroid you have this mass here, which is going to be the left lower parathyroid. Take this. Got it. Pickups. So we're going to start mobilizing it from medial, so just open that.
So we take care not to handle the parathyroid too much but rather just push it one way or another to avoid spilling tumor cells. I'm just going to adjust you a little bit of here. Alright, so I would grab the neck right now.
So now she's going to grab that like she means it, and I'm going to come around here - and we're going to ligate the - the - tumor - and the arterial blood supply. And she's going to use her tie to lift up the parathyroid. So you keep that deep, and then you pull very hard with that one. So let me set this first. Okay. Pickups - but don't pull too hard there. Yeah, that's a little bit more of it right there, so here is the - that's the esophagus, so just open - so nerve is going to be right here. Okay, so we're going to adjust this. So - so the parathyroid is extending, so stay right there. Take that now. Take that. So parathyroid is extending up underneath the thyroid gland. I'm just going to make sure we get it down here, and then that's the - just shine here. So that's the recurrent laryngeal nerve there, so what we going to do is we - you cut? Yeah. So just amputate it and then 3-0 tie. Come through all the way. Okay. Take a squirt. It's obviously important to resect the entire parathyroid adenoma because otherwise patient is at risk of recurrence. In this particular case, it was just a little lip of the parathyroid that was extending up underneath the thyroid, which we're making sure we're getting all parathyroid tissue. And now we're going to just adjust you a little bit there, so stay right there. We don't need to pull super hard. So now we're going to mobilize it from medial. And again, we're lifting it out - out of the TE groove to ensure a) we get all the tissue as well as preserving the recurrent laryngeal nerve. Okay. Okay. Just touch me. So left lower parathyroid.
So time zero is now. So now we're going to start checking the intraoperative PTH levels, so give us a squirt. So say - so say that one more time really loud. He - okay, beautiful. So again, to show the anatomy, here's the thyroid lobe. Just touch right here. And we're reflecting the thyroid lobe medially. Got the common carotid artery, the jugular vein, the esophagus is back here and sitting in its typical position. If you push the esophagus a little bit towards you, the recurrent laryngeal nerve right here - and then the parathyroid was sitting in a typical, utopic left lower position. In contrast, this is a typical normal appearing lymph node that could be mistaken for parathyroid, but that's a lymph node. Okay.
So now we're going to start closing, so tilt the table towards the midline. Take this.
So again, we take great care when we close the incision to have a nice cosmetic outcome. So first we close the strap muscle in the midline. And you want to just re-approximate the tissue - you don't want to take huge bites that makes it look bulky and swollen, but rather, you just want to re-approximate the muscle. It's not a strength layer. It's just to protect the underlying structures. And we'll leave about a centimeter at the bottom of the incision just in case there's some bleeding, and you have the opportunity to have that evacuated.
And then we will close the platysma in this similar manner with the running 3-0 vicryl, and as we're closing, the anesthesiologist is doing - drawing blood for a intraoperative PTH measurement. And if you could relax the pressure bag now and tilt the head up one click, and that's done to avoid any tension on the incision when you're closing. And similar as the strap muscle - just want to re-approximate the tissue without getting a lot of extra fat. You just want to close the actual platysma, which is very thin and thinner in the midline than laterally. We'll take a sloppy wet and dry next.
And most patients will have an excellent cosmetic outcome, meaning that the incision will be difficult to even see after several weeks to months, and the way we accomplish that is we use a small 5 - 5-0 Prolene, which we run. And then we use dermabond suture glue to close the incision, and then we pull out the suture right here and now in the operating room to avoid leaving any foreign material in the skin, which would cause an inflammatory reaction. So the combination of a small incision, avoiding sutures staying in the skin, and meticulous technique will give the best cosmetic outcome. Okay, so now the skin is closed.
You make sure that that slides - careful - and then put just one very thin layer of - of dermabond and then a steri-strip on top.
And then we're able to remove that suture, and now we're just going to wait for the parathyroid hormone levels to come back.
At the completion of the operation, I always make a operative drawing that is helpful for both patient education as well as summarizing the operation. So in this particular case, she had a normal appearing thyroid gland. The recurrent laryngeal nerve was in its utopic position, but sitting in the typical utopic left lower position was a significant enlarged parathyroid gland - what we label as the left lower parathyroid adenoma. And in this patient's particular case, her intraoperative PTH level at the baseline before we started the operation was 93. A drop into the normal range, which is 10 to 65 picograms per milliliter and more than 50% from the level of 93. So we will soon get numbers back from the intra-op PTH laboratory, which is just next door, which will measure it at time zero, 5 minutes, and 10 minutes, and so forth.
And during this whole procedure, patient's been comfortable, breathing by herself, and with some sedation. If the intraoperative PTH levels fail to normalize after removal of the left lower parathyroid adenoma, that would prove that the patient has disease in more than one gland, and we would then continue the operation. But the most likely scenario is we will see shortly is that her PTH levels will start - start to drop. And as you could see, the actual operation is relatively swift, meaning the actual operation’s probably around 15 minutes or so but then with some extra time to wait for PTH levels. The advantage with using local cervical block anesthesia over general anesthesia is the patient has a lower incidence of postoperative nausea and vomiting, less fatigue - there is quicker return to normal activities and work and overall enhanced post-operative outcome.
So some things to keep in mind when you perform this procedure is the use of anesthesia as you can see. Our go-to anesthesia modality is under local cervical block with - with sedation, but there's times when general anesthesia is preferable - and that could be when patient has significant sleep apnea, there's morbid obesity. Also, intraoperatively, we sometimes convert the procedure to general anesthesia, and that would be in a case where there's unsuspected thyroid nodules or other thyroid disease that would have to be dealt with as well as. If the tumor is very close to recurrent laryngeal nerve and the patient is uncomfortable and unable to lie still, we might elect to do general anesthesia in those - in those scenarios.
So the indications of minimally invasive parathyroid surgery is the same as for parathyroidectomy, meaning we follow the NIH guidelines for patients with asymptomatic disease. So if patient has symptoms, meaning osteoporosis, kidney stones, or other symptoms, we would offer surgery to all those patients. In patients that are asymptomatic, we have a detailed discussion about the risk and benefit, but if the patient is young or has a significant life expectancy - especially if they have neurocognitive symptoms, if they have severe hypercalcemia or hypercalciuria as well as some bone loss, those patients would be considered for surgery as well. Ultimately, it's that patient’s decision, and - and as long as they understand the potential risks and benefits, I think that's the most important.
So the risk of this procedure is mainly two-fold. One is injury to the recurrent laryngeal nerve, which could cause significant problems with the patient's voice. If you're having bilateral, that could lead to an unstable airway with the need for tracheostomy. That's never happened in my hands, but that's been described in the literature. The other potential complication is permanent hypoparathyroidism. That occurs when let's say the patient has four-gland hypoplasia, and when we leave a remnant of parathyroid tissue, we don't leave enough parathyroid chief cells. Then the patient wouldn't have enough PTH production, and thus, the patient would have the flip side of hyperparathyroidism, meaning hypoparathyroidism, where the calcium would be too low - so they would have to be treated with very high doses of calcium and - and vitamin D.
Nowadays, most surgeons that perform this procedure have been trained through endocrine surgery fellowship, and most fellowship throughout the country. There's about 20 of them around the country, and in most fellowships, the surgical fellow would be exposed to at least about a hundred parathyroidectomies. So once you've down a fellowship and you've down about hundred parathyroidectomies, you're probably facile enough that you can handle most of these cases. Still though, this can be a tricky operation, and even in the best of hands, sometimes the operation can be challenging.
If I were a patient, I think my major concern would be to ensure that the surgeon that does my parathyroidectomy has significant previous experience and has good preoperative imaging but also can handle challenges in the operating room - and that's usually related to previous training as well as previous experience. So if I were to have this operation, I would make sure I had an endocrine surgery fellowship trained surgeon performing my procedure that have significant experience in performing parathyroid surgery.