User:Thelmadatter/Sandboxes Group 2/Parathyroid transplant surgery

Parathyroid surgery

Parathyroid surgery is usually performed when there is hyperparathyroidism this conditions cause many diseases related with calcium reabsorption, because the principal function of the parathyroid hormone is to regulate it. Parathyroid surgery could be performed as two different ways the first one is the complete parathyroidectomy and the second one is the auto transplantation of the removed parathyroid glands.

Indications for the surgery

There are various conditions that can indicate the need for the removal or transplant of the parathyroid glands. Hyperparathyroidism is a condition caused by the extra production of the parathyroid glands, which can be divided in 3 types. Primary hyperparathyroidism happens when the normal mechanism of regulation of negative feedback of calcium is interrupted or in other words the amount of blood calcium is less than the production of PTH. Most of the time this is caused by adenomas, hyperplasia or carcinomas. Secondary hyperparathyroidism occurs normally in patients that suffer renal disease. The poor kidney function leads to a mineral disequilibrium causing that the organism, synthetize and release more PTH, makes the hypertrophy of the gland trying to compensate, for the disequilibrium. Tertiary hyperparathyroidism is developed when the hyperplastic gland constantly releases PTH after the secondary hyperparathyroidism independent to the regulation systems. Another condition is hypercalcemia, which refers to the rising of calcium level above 10.5 mg/dL one of the consequences of this, are heart rhythm diseases, an extra production of gastrin and peptic ulcers. Parathyroid transplant is recommended during thyroid surgery if the parathyroid glands are removed accidently during a thyroidectomy they must be auto transplanted to the sternocleidomastoid muscle because of the small distance or to the forearm that way another intervention would not be so risky. But first is recommended to make an biopsy to be sure that the transplanted tissue is parathyroid and not a lymph node with metastatic disease. During parathyroid surgery if there is an adenoma the transplantation is not recommended in stead it is cryopreserved for research an if there is a recurrent hypoparathyroidism. The surgery is indicated for all patients that are diagnosed with hyperparathyroidism with or without symptoms especially in younger patients. In some cases the surgery works as therapy for nephrolithiasis, bone changes and neuromuscular symptoms.

Procedure

Parathyroidectomy, or the removal of the parathyroids require general anesthesia the patient will be intubated and lays on supine position with the chin at fifteen degrees by elevating the shoulders to permit the extension of the neck. Then a transverse cut is made above the sternal notch. The transversal thyroid lobe is reached, and is rotated up to discover and ligates the thyroid vein to separate the thyroid artery. Exploration must be done meticulously to search for adenomas. If an adenoma is identified, exploration must be continue because it is common that more than one neoplasia appears. Before the procedure, the glands are marked to make them more visible during the procedure. If one of them cannot be found, the procedure is to remove a complete thyroid lobe on the side where the gland is not found to avoid an intrathyroid parathyroid gland. After exploration, if there is one, two or even three parathyroid glands affected, they are removed and the other one left in situ. If all four glands are affected then three and a half are removed. The remaining half is marked with a suture and the surgeon must be sure that the blood supply will not be compromised. A total parathyroidectomy or auto transplantation to the forearm of the remaining half gland can also be recommended.

Parathyroid auto transplantation

Parathyroid auto transplantation is part of the treatment when a patient has hyperparathyroidism and three or four parathyroid glands were already removed, but during the surgery one of the glands (in the case of the removal of three) is relocated at another part of the body to make, the procedure less risky another procedure. In the case of complete parathyroidectomy, a half gland is cryopreserved. In case the patient suffers hypoparathyroidism. If this happens the extracted parathyroid is relocated to another place of the body for example the forearm. Parathyroid auto transplantation begins with parathyroid tissue extraction, which must be preserved into a cold isotonic solution until the patient needs it. Research has shown that parathyroid tissue can function at subcutaneous level until the transplantation. If this is not possible, the most common procedure is to create a small pocket of muscle, tissue at least 2 cm deep by separating the muscular fibers. Then the parathyroid tissue is placed into and closed by suturing the area. After the extraction the tissue might be processed at the laboratory, as soon as possible. Once at the laboratory the tissue sample is placed at a frozen petri dish where it is cut into small pieces (approximately 1-2 mm). The small pieces are placed into test tubes and filled with a solution in three parts one at 20% of autologous serum (about 0.6 ml) and the other part of isotonic solution at 20% (about 0.6 ml) then a solution of 2 ml of polypropylene and mixed gently. Then is placed into a container at -70ºC for a night then finally the container passes trough the phase of liquid or vapor nitrogen immersion and is kept there until needed. When it is needed the sample is taken out of the nitrogen and placed into a bath of water at 37ºC until the ice is melted almost completely except for the samples core. Then 0.5 ml of the melted solution is removed and replaced for fresh isotonic solution.