Update on the current management of persistent and recurrent primary hyperparathyroidism after parathyroidectomy

Table 1 Anatomical location of the parathyroid glands

Type	Location
A1	Attached to the thyroid capsule
A2	Partially or completely embedded in the thyroid gland but outside the capsule
A3	Within the thyroid parenchyma
B1	Peripheral, existence of a natural gap space between parathyroid and thyroid gland
B2	Within the thymus gland
B3	Blood supply from thymic or mediastinal vessels

Table 2 Predictors of persistent/recurrent hyperparathyroidism occurrence

No.	Predictor
1	Age > 70
2	Obesity
3	ASA score 3
4	Low hospital case volume (n < 50/yr)
5	Inadequate surgeon’s experience
6	Ambiguous scintigraphy results with Sestamibi
7	Primary disease (single adenoma < double adenoma < parathyroid hyperplasia)
8	Surgical strategy (not recognizing the pathological gland, not applying bilateral cervical exploration in case of inadequate PTH reduction intraoperatively)

P-HPT: Persistent hyperparathyroidism; R-HPT: Recurrent hyperparathyroidism; PTH: Parathyroid hormone.

Table 3 Causes of operative treatment failure for primary hyperparathyroidism

No.	Cause
1	Failure to recognize histopathological lesion
2	Supernumerary (5th) parathyroid
3	Ectopic site of responsible parathyroid gland
4	Carcinoma or spread of adenoma parts
5	Inadequate experience of the surgeon
6	Insufficient cooperation with pathologist