Primary Hyperparathyroidism is suffered by patients who present with elevated
calcium serum levels and excessively high levels of parathormone.
Other characteristics are usually associated with it, but are not necessary for diagnosis.
In recent years, an alternative approach to parathyroidectomy has been developed.
Traditional surgery is performed under general anesthesia, and makes it possible to
explore all the glands.
By contrast, minimally invasive surgery is used in uniglandular disease with
preoperative location of the gland responsible for hyperparathyroidsm.
The SPECT-Tc 99 sestamibi and PET- CT scan are currently the most valuable
techniques to locate the gland prior to surgery.
This approach makes it possible to perform the surgery under local nerve blockade.
Several studies have concluded that a minimally invasive approach to primary
hyperparathyroidism is equivalent to bilateral exploration when intraoperative
parathyroid hormone (IOPTH) monitoring is used.
Some resolution criteria have been defined to make sure during the surgery that the
gland responsible for the disease has been correctly resected.
These are the current criteria
They equire a >50% drop from the highest preexcision PTH level, and/or PTH level
within the reference range 20 minutes post excision, and/or a PTH level 7.5 ng/dL
lower than the 10 minutes post excision level.
They require the IOPT to fall within the low normal range (<35 ng/dL) within 15
minutes from removing all hyper functioning parathyroid glands.
They require takimg a baseline preincision PTH sample before neck manipulation. A
PTH drop >50% from the baseline PTH level at 10 minutes from gland resection
indicates a successful operation.
But the most widely accepted guideline is the Miami criterion, which is a 50%
decline from the highest preincision or preexcision IOPTH level obtained 10 minutes
after excision of the hypersecreting parathyroid gland.
It is important to know that PTH has a half-life of 5 minutes to confirm the complete
excision of the diseased tissue.
Preoperative PTH must be measured.
To meet the Miami criterion, a PTH level measurement should be taken 5 minutes
from gland excisison.
PTH levels decrease by more than 50% once the gland has been succesfully removed.