Successful Parathyroid Surgery: safety is important in addition to elimination of disease

The success of parathyroid surgery is a combination of eliminating the abnormal parathyroid tissue and using a safe approach to protect the important structures adjacent to the parathyroid glands. Surgery for thyroid and parathyroid disease are similar in that both the thyroid surgeon and the parathyroid surgeon are aware of the vital structures adjacent to these glands. The glands in the body are typically close to important nerves, vessels, and arteries. In patients undergoing thyroid surgery or parathyroid surgery, the most important structures are the nerves that control the vocal cords and therefore control our ability to speak.

The goal of parathyroid surgery is lowering blood calcium via the removal of abnormal parathyroid gland(s). The ideal parathyroid surgery is based on the following important principles. A full evaluation prior to surgery allows the expert parathyroid surgeon to determine the diagnosis of primary hyperparathyroidism. This is done by a combination of blood tests measuring both parathyroid hormone and calcium levels. In certain cases, ionized calcium levels are helpful. An elevated ionized calcium level indicates the active calcium in the blood is too high. This is a more precise diagnostic test. For further assessment, vitamin D levels are measured. In complicated cases, sometimes there is a need to measure 24-hour urine calcium levels as well. Ultimately, the blood tests provide a precise diagnosis of primary hyperparathyroidism.

The second aspect of the treatment is to determine which of the four glands is involved or how many of the parathyroid glands are involved. Parathyroid hormone can be elevated when one or more glands are involved. There are several ways to identify the abnormal gland and to determine if the other glands are normal. The most commonly used test is a nuclear scan called a sestamibi parathyroid scan. Typically, sestamibi is a type of technetium that is used and is taken up specifically by the thyroid and the parathyroid glands. However, the sestamibi is washed out of the thyroid glands shortly after uptake where it lingers in abnormal parathyroid glands. Therefore, if there is an abnormally enlarged parathyroid gland, it will trap sestamibi which can be detected when the photographs are taken. This will often identify the abnormal gland. This test provides information on the number of glands that are abnormal in the location. Other options for identifying abnormal glands include ultrasound and MRI scans. Because a sestamibi nuclear scan is so highly effective, these other scans are rarely needed.

A common misconception about parathyroid disorders is that a negative scan implies that the diagnosis is incorrect. This is not true. Approximately 15% of all patients with hyperparathyroidism have a negative scan. The diagnosis of primary hyperparathyroidism is strictly made by blood levels of calcium and parathyroid hormone level. The presence of an abnormal area in this scan is totally dependent on the uptake of the nuclear material within that gland. There are many situations where there is no preferred uptake by the parathyroid gland which is an abnormal parathyroid, either being an adenoma or hyperplastic gland. One of the reasons for a negative scan, of course, is the skill of the interpreting physician. An expert parathyroid surgeon often can detect abnormalities on the gland that are not detected by the occasional interpreting physician. The second common reason for a negative scan is that there is multi-gland disease which results in a more diffuse uptake that is not as apparent. This is important information and allows the surgeon therefore the information he needs to explore all four glands. With the information he needs to determine whether he will explore only one or all four glands, the ability to succeed at surgery with efficiency is greatly enhanced.

The next important aspect of successful surgery for thyroid and parathyroid disease is providing the ultimate safety for the patient. The nerve integrity monitoring system during the surgery allows an early warning device to protect the recurrent laryngeal nerve and the superior laryngeal nerve. These nerves are in close proximity to the glands and therefore have to be protected in all situations. Meticulous surgical technique protects the nerves, but the additional safety of the nerve integrity monitoring system provides an extra level of comfort and maximal protection.

The next aspect of successful surgery and increased accuracy is the use of the gamma probe and the use of radio-guided surgery. By using an injection of nuclear material prior to surgery, the parathyroid gland will once again have selective uptake of this material. The radio-guided surgery allows the surgeon to identify this uptake with a use of a hand-held gamma probe. This provides amazing accuracy in detection of any abnormal area. The final step in successful surgery is the use of intraoperative assays to determine whether the elevated levels of parathyroid hormone have indeed decreased. This final step assures near complete success in almost every patient. In summary, the key points to successful parathyroid surgery are:

1. An surgeon who is experienced in the treatment of thyroid and parathyroid disease.
2. Preoperative scanning to identify whether it is a specific single gland or multiple glands. A negative gland implies multiple gland disease.
3. Surgical technique that is meticulous and precise.
4. The use of nerve integrity monitoring system during surgery to protect the superior and recurrent laryngeal nerves.