Thyroid, thyroid

Parathyroid gland reimplantation in 5 questions

Parathyroid gland reimplantation (also called autotransplantation) consists in transplanting fragments of a parathyroid gland (or part of it) into a muscle of the neck or of the forearm. The procedure aims to ensure the production of a sufficient amount of parathyroid hormone, a hormone that is essential for the regulation of calcium levels. In this article, we look at the reimplantation of parathyroid glands, the surgical procedure and the evidence on its safety and effectiveness. 
What is a parathyroid gland?
The parathyroid glands are located in the neck, behind and near the thyroid gland. These four very small glands, of 2 to 3 mm in diameter and which weigh 30 to 40 mg, secrete a hormone called parathyroid hormone (PTH). This hormone, also known as parathormone, is involved in regulating calcium levels in the blood. Too little parathyroid hormone production can lead to hypoparathyroidism, a medical condition caused by a lack of parathormone. This disorder can lead to hypocalcemia, or abnormally low blood calcium levels. Hypocalcemia can cause tremors, stiffness and muscle pain, as well as confusion and memory problems in some cases.
When is parathyroid gland reimplantation performed?
Parathyroid gland reimplantation or autotransplantation can be performed to reduce the risk of hypoparathyroidism if the parathyroid glands are accidentally removed during a thyroidectomy (thyroid gland removal), for example in the case of thyroid cancer.
 
The procedure can also be carried out as part of a parathyroidectomy or removal of the parathyroid glands, related to an overfunction of the parathyroid glands, called hyperparathyroidism.
How does the parathyroid gland reimplantation procedure work?
Parathyroid gland reimplantation can be done immediately during surgery or after cryopreservation of the glands (cooling at very low temperature). Fragments of the parathyroid glands are injected with a syringe into the sternocleidomastoid muscle of the neck or in the forearm, under the skin.
 
Is parathyroid gland reimplantation effective?
Parathyroid gland reimplantation or autotransplantation is a controversial procedure. Some studies have demonstrated its benefits, while others point to the risks.
 
For example, an Italian study concluded that parathyroid gland reimplantation in forearm subcutaneous tissue during thyroid surgery is a safe, easy and effective procedure. However, another study conducted by Chinese researchers shows that autotransplantation of a parathyroid gland does not affect the incidence of permanent hypoparathyroidism, but increases the risk of transient hypoparathyroidism when the rest of parathyroid glands are preserved in situ.
 
In addition, parathyroid gland reimplantation increases the duration of surgery and of post-operative patient recovery. In this context, in some countries, this procedure is only performed in hospitals and clinics with significant experience.
 
How can hypocalcemia related to hypoparathyroidism be treated or prevented?
If a clinical symptom and/or hypocalcemia is found after surgery, oral treatment including calcium and vitamin D derivatives may be prescribed.
 
In addition, innovative solutions such as fluorescence imaging help reduce the risk of accidental resection of the parathyroid glands. FLUOBEAM® LX is an imaging device exclusively dedicated to thyroid and parathyroid surgery, offering an aid in the detection of parathyroid glands through autofluorescence (fluorescent signal not induced by the injection of a dye) and a better assessment of their vascularization. The surgeon's gesture is guided with greater precision, which makes surgery safer and more effective. FLUOBEAM® LX is now used by reference centers in Europe and in the US.
 
A randomized clinical trial conducted in three French hospitals showed that the rate of accidental parathyroid resection was 2.5% with the use of autofluorescence vs. 12% in the control group. The rate of parathyroid autotransplantation was 3% and 13% respectively. Patients in the study were followed for 6 months. It revealed that the rate of postoperative hypocalcemia was significantly lower in the autofluorescence group (9%) compared to the control group (22%). And the rate of permanent hypocalcemia was 0% in the first group vs. 1.6% in the control group (that is 2 patients out of 120). This study has clearly demonstrated the clinical efficacy of autofluorescence for thyroid surgery, a real advance for endocrine surgery.
 
Dr. Fares Benmiloud, an Endocrine Surgeon at the European Hospital of Marseille in France, says about FLUOBEAM® LX: "NIR imaging used during total thyroidectomies significantly reduces postoperative hypocalcemia, improves the identification of parathyroid glands and reduces their autotransplantation rate"..
Parathyroid gland reimplantation is a delicate procedure, and its benefits remain subject to discussion. An appropriate treatment and the use of innovative technologies such as fluorescence imaging can help prevent postoperative hypocalcemia and treat it when it occurs..