Ultrasound (US) has become the most popular form of imaging of thyroid and parathyroid disease. Most US examinations can be performed in the outpatient setting, preferably by the thyroid/parathyroid surgeon. Dedicated thyroid ultrasonographers have a higher level of expertise in imaging in the central and inferior regions of the neck than the average radiologist who would customarily supervise a US technician in the radiology department and review only static images. The US imaging will not be able to see parathyroids that are not pathophysiologically enlarged. While US has more than 90% sensitivity in detecting single-gland parathyroid disease, in multigland sHPT the sensitivity is only 40% to 60%. The superior glands can be more challenging to image by US due to their posterior location and the overlying thyroid tissue. Inferior glands have a more variable location and higher likelihood of being ectopic. sHPT from vitamin D deficiency is a milder form, in which it would be uncommon to image any enlarged parathyroid glands by US in this patient population.

Sestamibi imaging is also frequently used for parathyroid localization, particularly if radio-guided surgical excision is planned. In patients in whom surgery is not indicated, this modality would not typically be required for the diagnosis or medical treatment of sHPT. Radio-guided surgery is a helpful adjunct in cases of renal-induced sHPT where the PTH is elevated above 1,000 pg/mL. Hyperplastic glands take up the radiotracer, assisting in the identification and confirmation of the identity of a hyperplastic gland.

A clear biochemical diagnosis of hyperparathyroidism should be the goal of the preoperative evaluation. For sHPT serum calcium and intact parathormone (PTH) should be measured. Typically the calcium is low normal or low, and the PTH is very elevated. Overall, low calcium reflects chronic depletion of the body’s calcium stores. Vitamin D testing is also very important in the sHPT patient population. If a patient is operated on for parathyroid disease with preexisting vitamin D deficiency, this could confound the results of any intraoperative parathyroid testing that might be used as part of the operative procedure, returning inappropriately elevated. Additionally, postoperative parathormonemia could result from vitamin D deficiency and not simply be viewed as a surgical failure.

Once the diagnosis has been made and US imaging has been obtained, preoperative injection of sestamibi may facilitate the radio-guided approach to the parathyroidectomy. A 2-cm incision is made halfway between the
cricoid cartilage and the sternal notch as has been described by Norman. Once the incision is open, subcutaneous adipose tissue is removed down to the level of the strap muscles in the midline. This provides exposure and working space through this minimal access incision. Blunt dissection is then used in this pocket, and the incision is then kept open with a retractor. The midline is opened with a Bovie cautery. Both the superficial and deep levels of strap muscles are separated in the midline vertically. Both the unilateral and bilateral exploration can then be performed through this approach (Figs. 21.1, 21.2 and 21.3).