There is general agreement that parathyroid surgery is technically demanding and that the average surgeon will encounter relatively few cases of this disease annually. Success rates of parathyroid surgery are of great interest to parathyroid surgeons and to patients as well, of course. By convention, a successful parathyroid operation is defined as one that achieves a normal calcium level for at least six months after surgery. Recently, due to the modernization of medical information technology, data on long-term success rates of parathyroid surgery in large populations have become available. To our knowledge, two studies of this nature have been published.
The figure illustrates long-term success rates of parathyroid surgery based on hospital experience. These results come from more than one thousand parathyroid operations performed over 15 years within a population of 3.5 million people in California. The figure shows that, not surprisingly, high-volume centers have the highest success rates, about 95% at the one year mark and 90% beyond one year. Low- and medium- volume hospitals have similar success rates of about 80% before the one year mark; thereafter, the success rate of low-volume hospitals appears to drop off significantly.
Now, you might be surprised to learn what counted as a high-volume hospital in this study. The typical high-volume hospital in this study performed an average of 15 parathyroid operations per year. What does this mean? Well, two things. First, most parathyroid operations are straightforward and can be completed with an excellent success rate by surgeons who perform parathyroid surgery more than once per month. Second, the role of the expert parathyroid surgeon is to raise the success rate from 90-95% long-term to 97-99% long-term. (Claims of success rates greater than 99% have not been confirmed by independent, third party audit.)
The study also identified several other factors that influence the success rate of parathyroid surgery:
Another population-based study on success rates of parathyroid surgery was performed through a national registry of more than one thousand parathyroid operations performed over 4 years in Sweden. (For more information on the Swedish endocrine surgery registry, visit www.thyroid-parathyroidsurgery.com). In the Swedish study, the success rate of parathyroid surgery was 93%. Use of intraoperative parathyroid hormone (PTH) testing improved success rates slightly. As was seen in the previous study, patients with negative sestamibi scans had lower success rates.
Summary: What does it mean to be an expert parathyroid surgeon?
We have already noted that surgeons performing an average of 15 parathyroid operations per year can deliver good results. However, since it is your neck we are talking about, most people desire the highest success rates they can find, which is understandable. Within the endocrine surgery community, a surgeon who performs 50 or more parathyroid operations per year is considered an expert parathyroid surgeon (see http://endocrinediseases.org/parathyroid/find_surgeon.shtml). By this definition, there are quite a few surgeons in the country who can deliver top notch success rates in the 97-99% range, and they can be found here. You might be wondering if there is any additional advantage to performing 100 operations per year. The answer is possibly a little, but not much, according to the available literature. There is nothing to suggest any added benefit from performing greater than 100 parathyroid operations per year. In other words, there is a point of diminishing returns, which is really not surprising since this pattern of diminishing returns is seen in many areas, from landing airplanes to pitching fastballs to playing Mozart. At some point that’s as good as it gets. For more information, see Finding an expert parathyroid surgeon.