310-461-0300

Contact Us

4 + 5 =

parathyroid-disease4 Gland Assessment

Customized 4 Gland Parathyroid Assessment

If you are diagnosed with hyperparathyroidism, then at least one of your four parathyroid glands is producing too much parathyroid hormone (PTH). The majority of patients will only have one abnormal parathyroid gland, however 10 – 15% of patients will have more than one parathyroid adenoma (benign tumor). To ensure the minimally invasive parathyroidectomy is a success, Dr. Babak Larian performs an individualized 4 gland parathyroid assessment on every patient.

4 Gland Parathyroid Assessment Tools

Intra-Operative PTH Testing

Today, 4 gland exploration is only to be used when localization scans came back negative and PTH levels are still high after removing one parathyroid gland. All 4 glands need to be biopsied because you cannot be sure that the gland that is slightly larger than the rest is in fact the abnormal one.

4 Gland Exploration

Today, 4 gland exploration is only to be used when localization scans came back negative and PTH levels are still high after removing one parathyroid gland. All 4 glands need to be biopsied because you cannot be sure that the gland that is slightly larger than the rest is in fact the abnormal one.

Minimally Invasive Radio Guidance

Minimally invasive radioguided parathyroidectomy uses a small injection of Tc-99m sestamibi (just like the sestambi scan) the morning of surgery. Radioactivity will concentrate in the abnormal parathyroid glands, making it easier to determine their location.

Localization Studies

Prior to surgery, localization scans, such as ultrasound, sestamibi scans, ultrasound, 4-D CT scan, or, rarely, MRI in order to determine the location of the parathyroid tumor. However, you cannot rely on these scans alone.

Intra-Operative PTH Testing Minimally Invasive Radio Guidance

Intra-operative PTH testing is vital to the success of surgery and is the true physiological marker of total parathyroid assessment. Minimally invasive radioguided parathyroidectomy uses a small injection of Tc-99m sestamibi (just like the sestambi scan) the morning of surgery. Radioactivity will concentrate in the abnormal parathyroid glands, making it easier to determine their location.

4 Gland Exploration Localization Studies

Today, 4 gland exploration is only to be used when localization scans came back negative and PTH levels are still high after removing one parathyroid gland. All 4 glands need to be biopsied because you cannot be sure that the gland that is slightly larger than the rest is in fact the abnormal one. Prior to surgery, localization scans, such as ultrasound, sestamibi scans, ultrasound, 4-D CT scan, or, rarely, MRI in order to determine the location of the parathyroid tumor. However, you cannot rely on these scans alone.

At the CENTER for Advanced Parathyroid Surgery, we are proud to offer safe, rapid, and effective parathyroid surgery using every cutting edge technique available, including minimally invasive parathyroidectomy, radio guided parathyroidectomy, rapid intra-operative PTH testing, and 4 gland assessment. Below you will find more detailed information about each 4 Gland Assessment technique.

Localization Studies
First, prior to parathyroid surgery, Dr. Larian will have the patient undergo localization scans, such as ultrasound, sestamibi scans, ultrasound, 4-D CT scan, or, rarely, MRI in order to determine the location of the parathyroid tumor. Identifying the affected gland(s) is key because in 20% of patients the parathyroid glands may not be in their normal location.

In the majority of cases, Dr. Larian will perform an ultrasound on the patient himself in his office to locate the abnormal parathyroid glands. Dr. Larian prefers to use an ultrasound, when possible, because it is less invasive and does not expose the patient to radiation, like a sestamibi or CT scan. With Dr. Larian’s extensive knowledge of parathyroid tumors, he is able to more accurately detect abnormal parathyroid glands in ultrasound imaging than those at an imaging facility who likely have limited experience scanning for parathyroid tumors.

If the ultrasound is unable to identify the location of the abnormal parathyroid gland(s), the patient should have a sestamibi scan. During a sestamibi scan, the patient is given a radiotracer that becomes absorbed by the abnormal parathyroid gland, so the location becomes visible. However, there are some significant limitations to sestamibi scans. First, other tissues are sometimes picked up by the scan, which can lead to a false positive reading. Next, the sestamibi scan has a 20% degree of error, in which there are some cells that just do not pick up the sestamibi. Further, if the patient has one very large abnormal parathyroid gland, and a second abnormal parathyroid gland that is suppressed (because the other gland is so large), this smaller, yet still abnormal gland, often times does not show up on a sestamibi scan.

PTH Testing
Intra-operative PTH testing is vital to the success of surgery and is the true physiological marker of total parathyroid assessment. It is through intra-operative PTH testing that Dr. Larian is able to almost always determine if all of the abnormal parathyroid glands have been removed.

Prior to surgery, Dr. Larian will measure the patient’s PTH level. Once he removes the first abnormal parathyroid gland, he waits 10 minutes and then re-measures the PTH level. Parathyroid hormone is cleared from the blood stream very quickly (the half-life of PTH is 5 minutes), so if the PTH level comes down by more than 50%, it confirms that the surgery has been successful and there are no more abnormal glands. In this scenario, in which the PTH levels have decreased by more than 50%, this 4 gland assessment technique is optimal. Knowing physiologically that PTH levels have normalized means that the patient does not need to undergo excess trauma that a 4 gland exploration can pose. Since Dr. Larian knows the patient has been cured, he does not need to search for the other 3 glands, which disturbs tissue and has the potential for injuring nerves or damaging the remaining parathyroid glands as a result of the biopsy.

Intra-operative PTH testing does extend then length of the surgery because we have to wait for the test results to be confirmed. However, given the risks of 4 gland exploration mentioned above, it is worth spending the extra time to utilize PTH testing.

However, if the PTH levels come back and are down by less than 50%, Dr. Larian knows there is at least one more hyperactive gland to identify and remove. At this point, Dr. Larian will need to perform the traditional 4 gland parathyroid exploration.

Minimally Invasive Radioguided Parathyroidectomy
Minimally invasive radioguided parathyroidectomy (MIRP) uses a radioguided probe to locate the abnormal parathyroid gland. The patient will be given a small injection of Tc-99 sestamibi (the same agent used during their initial sestamibi scan) prior to surgery. This agent makes the abnormal parathyroid glands radioactive, and visible, for three to four hours, and Dr. Larian will use a hand-held intraoperative detector, or probe, that guides him to the adenoma. The normal, healthy parathyroid glands do not absorb the agent because they are dormant, thus do not become radioactive. Radioguided parathyroidectomy is a great tool for locating the over-active parathyroid glands, as the probe detects the radioactive signals. The probe measures the amount of radioactivity in all 4 of the parathyroid glands; this is proportional to the amount of PTH being produced. However, this technique does have limitations to note. If there is more than one abnormal parathyroid gland, but one is producing such a larger amount of PTH that the other abnormal parathyroid has actually been suppressed, this tool will miss that second parathyroid tumor. Radioguided parathyroidectomy is generally a good technique when localization studies failed to show the parathyroid adenoma or gave a false reading, or when the abnormal parathyroid is located in an ectopic position. When performed by an expert, like Dr. Larian, and in conjunction with intraoperative PTH testing, radioguided parthyroidectomy proves successful for many patients.
4 Gland Parathyroid Exploration
Four gland parathyroid exploration was the standard for parathyroid operations 15 – 20 years ago, but is now considered the last technique to be used, only when localization scans came back negative and PTH levels are still high. In a four gland exploration, the surgeon needs to locate and biopsy all of the parathyroid glands. All 4 glands need to be biopsied because you cannot be sure that the gland that is slightly larger than the rest is in fact the abnormal one. When the abnormal gland is significantly larger, you know it is overactive. But if a gland is only slightly larger than it should be, you need to biopsy it to make sure you are not removing a normal gland. You must also find the other 3 parathyroid glands and biopsy those as well so that you can compare them all.

However, remember how small parathyroid glands are? The small size of theses glands makes the exploration method difficult for a few reasons. First, the small size of the glands makes locating the glands like finding a needle in a haystack. The glands can look like the fat surrounding them or lymph nodes, they can be in an abnormal location, etc. Next, once you do locate the gland (or think you locate the gland) there is a high risk of error in the biopsy. Sometimes surgeons will biopsy a lot of tissue, that turned out not to be a parathyroid gland, until they find the actual glands, which poses unnecessary trauma to the tissue. Once you do biopsy the parathyroid gland, you have to hope you make the perfect biopsy cut that actually goes through the fat so that it is an accurate sample. Abnormal cells will have a lower amount of fat in them than normal glands. But what can happen is that the biopsy will not have cut through the middle of the gland and missed the fat, leading the surgeon to believe that gland is abnormal. This method is too subjective and has a much lower success rate than the modern surgical techniques – intra-operative PTH testing and localization scans.

Examples of Customized 4 Gland Parathyroid Assessment

To give patients an idea of how Dr. Larian customizes every parathyroid surgery with an individualized 4 gland parathyroid assessment, below are a few examples of different surgical approaches:

Example #1

The patient has two abnormal parathyroid glands with one being larger than the other. Abnormal parathyroid gland A has a PTH level of 13 and abnormal parathyroid gland B has a PTH level of 11. Because gland A has a much larger PTH than gland B, gland B has become suppressed and has shrunken down in size. As a result, a sestamibi scan is likely only going to show us gland A and not gland B. In order to find gland B during surgery, Dr. Larian will need to very meticulously find gland B through 4 gland exploration and PTH testing.

Example #2

Prior to surgery, the patient has a PTH of 300. From localization studies, Dr. Larian was able to find the abnormal gland. Within minutes, Dr. Larian finds and removes the large parathyroid gland and then performs intra-operative PTH testing. The PTH comes back as a level of 12. As a result of the PTH measurement of 12, Dr. Larian knows the surgery has been a success.

Example #3

In localization scans you do not see any glands, but the PTH levels are incredibly high. Most likely the patient has hyperplasia, all 4 glands are abnormal. In this scenario, Dr. Larian will need to perform a 4 gland exploration and biopsy all of the parathyroid glands to determine if all 4 glands are in fact abnormal.

Consult With Dr. Larian Today.

Request An Appointment Online