UF Researcher: Standard Surgery Is Best Treatment For Hyperparathyroidism
GAINESVILLE, Fla. — A University of Florida surgeon is calling for a return to a more traditional surgical treatment for a hormonal imbalance that causes a constellation of symptoms doctors have coined “moans, groans, stones and bones.”
People who develop the disease primary hyperparathyroidism lose the ability to regulate mineral levels in the blood because of benign tumors that grow in one or two of the four pea-sized parathyroid glands found in the neck. As the glands enlarge, most patients produce excessive levels of parathyroid hormone, which triggers imbalances in calcium and phosphorus and leads to debilitating complications of the bone and muscle.
Study findings show that a traditional operation called bilateral neck exploration is superior to the minimally invasive technique that has gained recent popularity – in part because it is “minimally expensive” by comparison and, more important, because it easily detects additional affected glands in some patients, preventing the need for a second surgery and its risks later, says Dr. Scott Schell, an assistant professor of surgery, medicine, and molecular genetics and microbiology at UF’s College of Medicine. UF and Oxford University surgeons describe their analysis in the current issue of the journal Surgery.
Schell said the results help quash the long-standing debate among surgeons about which procedure is best, particularly those who promote the minimally invasive approach as the fastest, most successful and cheapest treatment for the disease.
Primary hyperparathyroidism afflicts about one in every 300 to 500 postmenopausal women, for reasons that aren’t entirely understood, said Schell, who also is affiliated with the UF Institute on Aging. About a third as many men develop the disease, which is usually detected by routine blood testing as part of a standard physical examination.
“The calcium ion is absolutely essential for every physiologic process in the body,” he said. “Whereas we typically think of calcium in terms of bone density and strength, it literally is intimately associated with all nervous function, memory, movement, stomach function, kidney function, skin, nails, everything. When people have high blood calcium levels, in addition to being at significant risk of losing bone mass, which is a serious problem, they also frequently have an assortment of symptoms called ‘moans, groans, stones and bones.’ And so they’ll get kidney stones, for example, because calcium comes out of solution in the urine. They also can develop pancreatitis and other miserable symptoms.
“The most worrying concerns from untreated high calcium are that over time, you could lose the function of your kidneys, or you could critically lose so much bone you couldn’t rebuild it, or you could develop a number of bad consequences from untreated high blood pressure and heart disease,” he said.
The standard surgical treatment involves making a small incision in the neck above the collar line to take out the tumor and to examine the other parathyroid glands to make sure they are healthy. But after a new nuclear medicine imaging technique developed in the late 1980s accurately identified which of the four parathyroid glands was enlarged about 85 percent of the time, Schell said, an increasing number of surgeons began using it in conjunction with minimally invasive surgery, which uses an even smaller incision and, some argue, leaves less scarring.
But up to 4 percent of patients with primary hyperparathyroidism actually have two abnormal glands, not one, and surgeons who use the minimally invasive technique may miss other affected glands because they are never visible, Schell said. Numerous studies have shown the scans often fail when patients have small tumors or tumors affecting more than one gland, he said, and having to operate again later on doubles or triples a patient’s risk of complications.
“In those cases you end up not doing the right operation – you leave the disease behind,” he said. “As technically challenging as neck surgery is, it’s much worse if we have to do it again because of the scarring that happens after surgery. So there has been a significant and heated controversy between classic endocrine surgeons and surgeons who favor the minimally invasive approach.”
UF and Oxford scientists examined the two surgical methods to assess patient outcome and to weigh the costs involved with each technique. They evaluated the medical records of nearly 700 British patients who had undergone full exploration of both sides of the neck using a blue dye to help identify the parathyroid glands. These patients were treated between 1968 and 2000 at the University Teaching Hospitals in Oxford, England. The researchers compared their outcomes with data from previous reports of 68 patients who underwent scan-directed minimally invasive parathyroid surgery at other centers.
“I think it definitely puts to rest the assertion by proponents of minimally invasive surgery that their method is better and less expensive,” Schell said. “We showed very plainly that contrary to the assertions published in the past, minimally invasive parathyroid surgery is not more cost effective – in fact, it’s about one-third more expensive to treat patients this way. And I think if you evaluate our data it would lead you to believe that there’s going to be a subset of our patient population – about 15 percent – who don’t get the right surgery for their disease if they have minimally invasive parathryoidectomy, because they have an additional affected gland that goes undetected at the time of the operation.”
In contrast, researchers found the standard surgery cured patients – returning their blood calcium and parathyroid hormone levels to normal within a year of surgery – about 98 percent of the time, without serious complications.
“First of all, you don’t have to spend the money required to do the scan and to read the scan,” Schell said. “And if you give patients methylene blue dye, as opposed to hundreds of dollars, it costs only about $39 per patient. It stains the parathyroid glands bright blue and makes it much easier to see the glands while operating. The scan is not necessary from a technical standpoint if you know what you’re doing. Affected glands are enlarged and have a characteristic appearance; it’s very plainly obvious which ones are which. If you perform the minimally invasive surgery, you’re not in a position to make the effort to look. We look at all the glands to make sure they are normal, and if they’re not, we remove them.”
The parathyroid glands are easier to view during a bilateral approach than a minimally invasive approach because the incision is larger, although the minimally invasive technique is less likely to damage nerves or other parathyroid glands, said Dr. Orlo H. Clark, a professor and vice chairman of surgery at the University of California-San Francisco.
“Bilateral neck exploration by an experienced surgeon is highly effective and is more likely to identify more histologically abnormal parathyroid glands,” Clark said. “Whether these parathyroid glands will prove to be functionally abnormal is not yet known.”