A Novel Classification of Parathyroid Glands and Their Preservation in Thyroidectomy

Introduction:

Hypoparathyroidism is the most frequent complication after thyroidectomy and is caused by inadvertent gland injury, removal, or devascularization. To preserve the parathyroid effectively, we recorded the parathyroid glands based on their anatomic characteristics.^1–2 To avoid hypoparathyroidism, the parathyroid glands should be identified and preserved in situ. ³ In a few unusual circumstances, devascularized glands that cannot be preserved should be transplanted during surgery. ⁴ However, various locations and blood vessels make the preservation of parathyroid glands difficult.

Materials and Methods:

Parathyroid glands were classified into three types, considering their blood supply and location. ⁵

Type A: The unattached type, that is, the secure or thymus type—the parathyroid glands are located outside the thyroid gland and have an independent blood supply. They are mostly safe unless patients undergo central compartment neck dissection.

Type B: The half-attached type

B1. The parathyroid glands are located on the surface of the thyroid gland and have a clear blood supply. These vessels are independent of the thyroid gland, and it is easy to preserve the blood vessels of the parathyroid gland during thyroidectomy.

B2. The parathyroid glands are situated on the surface of the thyroid. The blood supply of the parathyroid gland is partially from the thyroid gland or its communicating branches. When separated from the thyroid gland, the parathyroid glands change in color from light red to dark red, for which, decompression should be performed by making an incision.

B3. The parathyroid glands are located on the surface of the thyroid and are often found on the lateral thyroid lobe, which is far from the tracheal axis. The blood supply is partially from the vessels supplying the thyroid gland, and these vessels are hard to preserve. However, there is an opportunity to try to preserve them as type B2. If the separation is ineffective, these glands will be considered type C and need to be transplanted.

Type C: The completely attached type—the parathyroid glands are embedded within the thyroid and receive their blood supply directly from the thyroid gland. Therefore, it is difficult to preserve them in situ during total thyroidectomy.

Results:

All of parathyroid glands were confirmed histologically by frozen sections.

Conclusions:

Parathyroid glands can be classified into three types based on their locations and blood supply. The difficulty of preserving each type of parathyroid gland differed. Surgeons should use different surgical techniques to treat each type.

Acknowledgments:

This work was supported from the key program of health and family planning commission of Hubei province (Grant No. WJ2015MA003) and the young thyroid doctors' research projects supported by International Medical Foundation of China in 2015 (Grant No. 2016026).

No competing financial interests exist.

Runtime of video: 3 mins 39 secs