B6.050 Large Group Hyperparathyroidism

Question 1

options for preoperative localization of parathyroid glands

Answer 1

ultrasound
sestamibi nuclear medicine scan
4D parathyroid CT
MRI
selective venous sampling
arteriography

Question 2

ultrasound

Answer 2

allows thyroid interrogation as well as occasional parathyroid identification
-hypervascular homogenous extrathyroid nodule

Question 3

sestamibi nuclear medicine scan

Answer 3

gold standard in parathyroid localization
negative in 12-25% of patients with parathyroid adenomas
accuracy decreased with thyroid disease
should be paired with SPECT imaging for best results

Question 4

process of sestamibi nuclear medicine scan

Answer 4

patient injected with 20-25 mCi of Tc 99m sestamibi

subsequent images at 10-15 min and 2-3 hours

Question 5

how does sestamibi nuclear medicine scan work

Answer 5

thyroid and thyroid nodules clear uptake faster than parathyroid neoplasms do
Tc99m is incorporated into the cytoplasm and mitochondria, parathyroid tissue has a large number of mitochondria in its oxyphil cells compared to thyroid tissue, allowing Tc99m to enter parathyroid tissue more intensely

Question 6

limitations of sestamibi nuclear medicine scan

Answer 6

1-3% false positive rate

can’t identify multigaldular disease

Question 7

selective venous sampling

Answer 7

used in reoperative settings and when there are multiple negative non-invasive imaging studies
catheter samples PTH at every venous entry point to see where the parathyroid gland drains

Question 8

archetypal parathyroid surgery

Answer 8

four gland exploration

still valid, but rarely used

Question 9

most common surgical approach at high volume center

Answer 9

minimally invasive parathyroidectomy
“keyhole”
focused

Question 10

describe the process of minimally invasive parathyroidectomy

Answer 10

incision < 1 in
made possible by: preop localization, intraop PTH monitoring
no endoscopic or laparoscopic instruments

Question 11

what is intraoperative PTH monitoring

Answer 11

rapid assay of PTH (8 min to result) allows determination of biochemical cure while patient is asleep
guides operative exploration or closure
blood drawn from internal jugular or peripherally

Question 12

how is intraoperative PTH monitoring performed

Answer 12

baseline PTH prior to resection is compare to repeated values 5, 10, and 15 min after implicated gland is removed
decline of PTH by 50% baseline at 10m as well as into the normal range is successful

Question 13

when is cryopreservation used?

Answer 13

for patients with secondary HPTH who are undergoing either subtotal or total parathyroidectomy with auto transplantation

Question 14

how is cryopreservation performed

Answer 14

additional parathyroid tissue is cryopreserved on the sterile field
tissue can be thawed and re-implanted at a later date should the patient’s in situ or auto transplanted parathyroid tissue not survive
avoids surgical hypoparathyroidism