Sanne Høxbroe Michaelsen

What is the title of your thesis?

Surgeon-performed imaging of the parathyroid glands in a pre- and intraoperative setting.

At which department and/or research unit did you complete your PhD?

The Research Unit at the Department of Otorhinolaryngology/Department of Audiology, Department F, Odense University Hospital, and the Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark.

Who was your principal supervisor?

Consultant, PhD Viveque Egsgaard Nielsen.

What question did you aim to answer with your thesis?

The human body has four parathyroid glands, which are located behind the thyroid gland in the neck. The parathyroid glands regulate the amount of calcium in the blood. Neck surgeons need to identify the parathyroid glands in two different situations:

1) When a parathyroid gland has become overactive and needs to be surgically removed, and 2) when a patient needs to have their thyroid gland removed without the surgeon inadvertently removing or damaging the nearby parathyroid glands.

My PhD thesis investigates hands-on real-time imaging techniques for parathyroid identification that surgeons can employ in the abovementioned settings. I also investigated the extent of inadvertent damage to the parathyroid glands in our department over a 10-year period.

What did you find?

Re 1) I found that surgeons with experience in parathyroid ultrasound can use ultrasound as the primary imaging modality to localize overactive parathyroid glands prior to surgery. If the overactive gland is clearly visible on ultrasound, there is no need to acquire supplemental scans, which incur additional costs and expose patients to ionizing radiation.

Re 2) I found that the occurrence of inadvertent damage to the parathyroid glands during thyroid surgery can be significantly reduced if the surgeon uses near-infrared light combined with a fluorescent contrast agent to visualize the parathyroid glands and their blood vessels.

How did you do it?

Re 1) Patients with one or more overactive parathyroid glands underwent both an ultrasound scan and a more extensive scan (scintigraphy) prior to having the overactive gland(s) surgically removed. The ultrasound scan was performed by a neck surgeon who did not know the result of the scintigraphy. Once the surgically removed tissue had been evaluated, we compared how often each of the two scans had in fact identified an overactive parathyroid gland.

Re 2) First, I determined the incidence of inadvertent damage to the parathyroid glands during surgical removal of the entire thyroid gland over the past 10 years at our department. Over the next two years, we then used a combination of near-infrared light and a fluorescent contrast agent to visualize the parathyroid glands and their blood vessels when performing the same type of surgery at our department. We then compared the incidence of inadvertent parathyroid damage during the 10-year and the two-year period.

How can your research be applied (in the clinic, society, etc.)?

Re 1) The research can help us make wise choices in healthcare, so that we do not automatically perform expensive and extensive scans before determining whether a simpler type of scan is adequate.

Re 2) The research can help reduce the occurrence of the most common complication following removal of the entire thyroid gland, which would otherwise result in a chronic deficiency of parathyroid hormone, which (often) requires lifelong medical treatment.