Anatomy:

Thyroid gland – glandulathyroidea: endocrine butterfly-shaped organ located in front of the trachea. It is affixed to the trachea with ligamentum suspensorium glandulaethyroideae – ligamentum Berry. It consists of two lobes that are connected by a bridge (isthmus), which is at the level of 2nd-

 - 4th ring of the trachea. Variably, lobus pyramidalis - a remnant of ductus thyroglossus branching out from the isthmus in cranial direction - occurs in 1/4 of cases.

Topography:

Facies medialis: adjacent to the larynx and trachea, near the nervus laryngeusrecurrens.

Facies anterolateralis: including the isthmus, surrounded by the infrahyoid muscles of the lamina pretrachealis fasciae colli.

Facies dorsalis: located near the neurovascular bundle through which a. carotis communis, v. jugularis interna, and n. vagus passes and in which the parathyroid glands are partially embedded.

Ligamentum Berry extends between the thyroid capsule and the annular and thyroid cartilage. It is located right next to n. laryngeusrecurrens. Together with the lobus pyramidalis, this is the location along which the remnants of thyroid tissue remain the most often after thyroidectomy. 

In adulthood, the thyroid gland weighs approximately 15 - 20g.  It is very richly vascularized and makes its hormones in response to iodine supply.  The hormones pass directly into the blood.  The thyroid gland consists of a large number of follicles. Their walls are made up of cubical follicular cells.  The pouches are filled with a brown, jelly-like, viscous fluid - a colloid, which is a reservoir of hormones bound to the protein thyreoglobulin.

Innervation of the thyroid gland is provided by sympathetic nerves.

The vascularization is dual - a. thyroidea superior leads from a. carotis externa and a. thyroidea inferior leads from a. subclavia.  The blood flow through the thyroid gland is about 5 ml/1g of gland tissue/minute, which means that in an hour, all the blood in the body flows through this small gland.

The lymphatic drainage is divided into ascending, which collects lymph into the pretracheal and prelaryngeal nodes, and descending, which leads to the cervical deep nodes and nodes of the superior mediastinum. 

Thyroid hormones

The follicular cells of the thyroid gland produce the Triiodothyronine(T3) and tetraiodothyronine thyroxine (T4) thyroid hormones, which are derivatives of the tyrosine amino acid covalently bound to iodine. Structurally, these are two molecules of tyrosine and iodine at three or four positions of the aromatic ring. Functional hormones are released from the iodinated glycoprotein thyroglobulin.

Thyroid hormone production is strictly feedback regulated.  TSH (thyrotropic hormone) is the most important hormone and it is produced by the anterior lobe of the pituitary gland. It is the master regulator of thyroid hormone production and secretion and thyroid growth. The regulation is performed via negative feedback of T4 and T3 The synthesis and secretion of TSH is stimulated by the tripeptide TRH (thyreotropine-releasing hormone), which is produced mainly in the hypothalamus.

Thyroid hormones have a different significance in the intrauterine period (differentiation factor) and after birth, they have a beneficial effect on the development of the human brain. The main effect of thyroid hormones is on metabolic processes, increasing basal metabolism, blood pressure, heart rate and heart muscle strength - that is, they increase cardiac work.

In addition to the already mentioned hormones that affect metabolism, the thyroid gland creates the calcitonin hormone, which reduces the level of calcium and phosphorus in the blood, and also hormones thermothyrin A and B, which regulate body temperature.

Hypothyroidism - Hypofunction of the thyroid gland refers to insufficient production of thyroid hormones.  At an early age, it leads to growth retardation, the bones are short and wide, overall height is small, skin is dry, at the same time, hair and teeth growth is limited, a decrease in metabolism and a delay in sexual and mental development - cretinism occur.In adulthood, the hypofunction of thyroid hormones produces similar symptoms: a decrease in basal metabolism, body temperature, heart function slows down, blood pressure and muscle tone decrease, nerve communication and neuromuscular transmission slow down. Specific proteins accumulate in the subcutaneous tissue, fatness occurs, fatigue often sets in, and disturbances in mental activity occur - in particular, the psychomotor pace slows down, the person has a harder time understanding, they forget and their thinking is slow.  Administration of thyroid hormones eliminates these symptoms.

Hyperthyreosis - hyperfunction of the thyroid gland or an excessive production of thyroid hormones is manifested by an increase in basal metabolism, an increase in body temperature, accelerated heart activity - increased heart work - tachycardia, increased blood pressure, moist skin, acceleration of nerve excitations and neuromuscular transmission.  Mental disorders occur - insomnia, nervousness, trembling of fingers. 

Graves - Based disease, an autoimmune disease, is the most common cause of hyperthyroidism.  Antibodies to the TSH receptor are formed in the body, and they activate and increase the production of thyroid hormones (T3, T4), the same antibodies can also bind to antigens in the retrobulbar space (causing endocrine orbitopathy - exophthalmos), in the subcutaneous tissue of the tibiae (pretibial myxedema) and on hands and feet (acropachia).

Other causes of hyperthyroidism include hyperfunctioning struma (enlargement of thyroid volume above the norm for given age), hyperfunctioning adenoma, TSH-secreting pituitary adenoma.

An enlargement of the thyroid gland -  struma - can often be observed in both disorders.

Thyrotoxicosis is a condition during which tissues are exposed to high levels of circulating thyroid hormones.Hyperthyroidism, that is, excessive thyroid gland function is the most common cause of thyrotoxicosis.  That is why the two terms are often mistaken for each other in practice.

Examination of the thyroid gland

The prevalence of thyreopathy in the Czech Republic is approximately 5 % of the population.  This percentage rises up to 10-15 % in case of middle-aged and older women. Thyroid function tests are often performed only when clinical symptoms are present, which can be very non-specific, e.g. in hypothyroidism. In patients with increased risk of hypothyroidism, TSH levels should be checked every 2-4 years.

Indications for thyroid testing are: 

• thyroidopathy in family or medical history
• enlargement of the thyroid gland
• autoimmune or immunopathological diseases in medical history, such as type 1 diabetes mellitus, celiac disease, multiple sclerosis
• use of medication such as Amiodarone, cytokines, lithium
• excess or deficiency of iodine in diet
• previous treatment with radioiodine
• irradiation of the neck and upper chest
• women over 50 years of age

o   pregnant women for whom screening of TSH and TPOAb (thyroid peroxidase antibodies) levels is recommended, ideally before conception or in the first weeks of pregnancy

Medical history:When taking a medical history, we mainly assess the following signs of thyroid-related disease:

o   heart rate, blood pressure, temperature, weight, skin condition, muscle contractions

o   struma - mechanical compression with signs of oppression of the surrounding structures. Oppression of blood vessels in the case of retrosternal struma. breathing and swallowing difficulties, hoarseness, eyelid swelling, exophthalmos.

Physical examination: if the thyroid gland is without pathology, it cannot be seen or palpated.  Any enlargement of the thyroid gland is referred to as struma, this can also be seen during swallowing.  However, palpation is the decisive factor.  During palpation, the patient bends his head slightly forward to relax the neck muscles.  We palpate the edges of the thyroid gland at rest and during swallowing.  We assess size, symmetry, asymmetry, surface and consistency of the thyroid gland, tenderness, and last but not least, mobility against the skin but also the base layers.

Imaging methods

o   Ultrasound - the first choice method, it has no contraindications or risks and can be used to distinguish localized changes and to determine the size, location and relationship to the surrounding structures and the structure of the thyroid gland.

o   Scintigraphy - this is a radioisotope examination in which we evaluate the distribution of radiopharmaceuticals (iodine-131, Technetium-99m).  A healthy thyroid collects radiopharmaceuticals uniformly, in case of a pathology, a change in the accumulation of radiopharmaceuticals occurs. 

§  A uniform decrease in iodine accumulation can be observed in hypothyroidism

§  A uniform increase in iodine accumulation can be observed in hyperthyroidism

§  Furthermore, we distinguish between “cold” nodules, in which a part of the thyroid gland collects radiopharmaceuticals to a limited extent or not at all (cysts, scars, non-functional adenomas, undifferentiated carcinomas) and “hot” nodules, in which increased accumulation (differentiated carcinomas, hyperfunctional adenomas) occurs.

§  Scintigraphy is also used to exclude metastases, residues after surgery or recurrence

o   X-ray - plain image of the upper thoracic aperture is used to assess possible deviation of the oesophagus or trachea

o   CT scan - is indicated for large strumas with retrosternal spread, we can also evaluate the cervical lymph nodes better

o   MRI - has the same indications as CT scan, but without the radiological burden

FNAB (fine needle aspiration biopsy) - this involves puncturing the thyroid gland with a fine needle and taking a sample for cytological examination.

 FNAB is indicated where an ultrasound scan has revealed one or more nodules to rule out possible thyroid cancer

Bethesda classification - used to evaluate FNAC (fine needle aspiration cytology) and classify the risk of malignancy.

I - III we repeat FNAC, 

II monitor nodule growth by ultrasound and in case of significant growth, we repeat FNAB (FNAC) 

IV is an indication for hemi- or total thyroidectomy and histological verification

V-VI is an indication for total thyroidectomy as a therapeutic procedure

Table 1:  Standard international classification of thyroid FNAC - Bethesda 2010

Laboratory results:

o   Anti-Tg (anti-thyroglobulin), Anti-TPO (anti-thyroid peroxidase antibodies) their elevated levels indicate autoimmune thyroid disease

o   TRAK (anti-TSH receptor antibodies) - their presence indicates Graves’ disease

o   Thyroglobulin - elevated levels in case of thyroiditis or cancer, also used to assess the success of treatment

o   Triiodothyronine T3, thyroxine T4 - hypo/hyperthyroidism

Indications for surgery - endocrinologist determines the indication, including the extent and timing, surgeon modifies the course of surgery according to perioperative findings if necessary

·       Mechanical syndrome, progression in growth, ineffectiveness of conservative therapy

·       Thyrotoxicosis

·       Inflammatory involvement - Abscess, Hashimoto's thyroiditis - mechanical syndrome

·       Congenital developmental diseases

·       Benign/malignant tumors

Surgery types:

·       Total thyroidectomy - TTE - removal of all thyroid tissue

o   Indications of TTE include malignant tumors, toxic polynodous struma, toxic adenoma, struma with signs of oppression, medically uncompensated Graves’ disease. TTE is also indicated in female patients trying to conceive with this diagnosis

·       nTTE (near-total thyroidectomy) - leaving tissue remnants up to 4mm in size

·       Extended TTE - TTE + cervical lymph node sector I-VI, especially indicated in papillary carcinoma, due to early metastasis to the nodes

·       Hemithyroidectomy - HTE - lobectomy + resection of isthmus

·       Lobectomy - resection of the thyroid lobe with preservation of the isthmus

·       Subtotal thyroidectomy, resection of isthmus, open biopsy

Total thyroidectomy

2 surgical modalities are currently established in surgical practice.  “Open” thyroidectomy and minimally invasive video-assisted thyroidectomy.

The open surgical procedure is based on the Kocher surgical methodology using classical instrumentation with an emphasis on isolated treatment of the vessels and visualization of the recurrent nerve. After the introduction of first bipolar coagulation and then the harmonic scalpel into surgical practice, time-conscious thyroidectomy has become faster and easier for the surgeon. 

(MIVAPT/MIVAT: Minimally Invasive Video-Assisted Parathyroidectomy/Thyroidectomy)

Purely endoscopically, thyroidectomy can be performed from a cervical or extracervical approach. In case of the cervical approach, the procedure is performed under continuous CO2 insufflation of the visceral space of the neck at a low pressure of about 6-8 mm Hg.  Unlike conventional thyroidectomy, neck hyperextension is not performed.  Similarly, the procedure can also be performed from a lateral cervical approach with an endoscope inserted at the anterior margin of m. sternocleidomastoideus.Extracervical endoscopic procedures use incisions outside the neck (axilla, breast) and access to the thyroid gland by creating long subcutaneous or submuscular tunnels through which instruments and the endoscope are introduced.  The procedures are performed either under continuous low-pressure CO2 insufflation or with a special retractor introduced from the axilla.  Classical laparoscopic instrumentation is then used to perform the actual procedure.  Extracervical techniques are undoubtedly the most demanding of endoscopic thyroid procedures.  They have achieved the greatest popularity and spread in Asia.  The longer post-procedure hospitalization and soreness is balanced by the absence of scarring in the neck region.  Currently, a technique called transoral video-assisted thyroidectomy (TOVAT) is being developed and it uses an incision in the floor of the mouth.  Suitable patient selection is a prerequisite for good results of minimally invasive thyroidectomy techniques.  The size of the thyroid gland and the pathologies localized in it are the limiting factor in particular.

Post-surgery care and possible complications

After the surgery, the patient is monitored in the intensive care unit.  Monitoring for early complications of surgery, especially bleeding from the surgical field, in which urgent revision and treatment of bleeding is necessary, with impending dyspnea caused by oppression of the hematoma on the trachea.  A feared complication is the injury to the n. laryngeusrecurrens, in which unilateral injury results in hoarseness, bilateral injury results in dyspnoea with the need to secure the airways with a temporary or permanent tracheostomy.  We also monitor patients for symptoms that may be caused by hypocalcemia, as the parathyroid glands may be removed or injured, which results in decreased parathyroid hormone levels.  These symptoms include: paresthesia, tingling, muscle spasms, Chvostek sign (when tapping on a branch of the facial nerve, preferably over the glandulaparotis or closer to the corner of the mouth, a homolateral twitch of the upper lip philtrum towards the side of the tap.  This is a sign of increased neural excitability). Finally, infection in the surgical wound, thyrotoxic storm, adhesions and keloid scar may also occur.  After conclusion of hospitalization, the patient is referred back to the care of an endocrinologist.

Perioperative monitoring - neurostimulation of the laryngeusrecurrens nerve

With this method, the surgeon is informed about the position of the laryngeusrecurrens during the procedure.  This method significantly reduces the risk of injury to this nerve.  Two electrodes are used for monitoring: the first is inserted transligamentally through the ligamentum conicum to scan vocal cord contraction/movement, the second is inserted into the striated muscle on the adjacent side to the n. laryngeusrecurrens.  By inserting the stimulation probe into the surgical field, the recurrent nerve is detected, and its detection is converted into an acoustic signal that is heard by the surgeon and which provides evidence of the intactness of this nerve.

Pathological findings

Congenital developmental defects - are detected during the newborn's stay in the maternity hospital by drawing blood (TSH) from the heel as part of the newborn screening.  These include thyroid aplasia and hypoplasia, in which the thyroid gland is developed but underdeveloped, which is manifested by cretinism.

Struma - is a term for enlargement of the thyroid gland, it may or may not be associated with a change in thyroid function.  We differentiate diffuse struma, in which the thyroid gland as a whole is enlarged, and nodular struma, in which one or more thyroid foci are enlarged and nodules are formed.  Struma may be caused by iodine deficiency in a person’s diet, exposure to strumigens, autoimmune inflammation, disorders of the enzymes necessary for the production of thyroid hormones, and tumors.

Thyroiditis 

·       Acute thyroiditis - a suppurative inflammation of the thyroid gland, cause of which can most often be found in the orofacial region, manifested by local redness over the thyroid gland, palpatory tenderness, fever.

·       Subacute thyroiditis - or De Quervain's thyroiditis, it is caused by a viral infection of the upper respiratory tract, the symptoms of inflammation are accompanied by palpitations, sweating and nervousness

·       Chronic form of inflammation 

o   Hashimoto's thyroiditis - an autoimmune inflammation of the thyroid gland, which occurs 4 times more often in women and causes hypothyroidism, there is also a risk of malignancy, it manifests with a more rigid, palpable and painless struma, and its development is slower.

o   Riedel's thyroiditis - it is rare, caused by fibrous transformation of the gland, rigid upon palpation, fixed, and it may be associated with thyroid hypofunction

Benign thyroid tumours

Thyroid adenoma - the most common, mainly affects women over 50 years of age, its etiology is unknown. It is encapsulated and well differentiated, it may manifest itself with thyrotoxicosis - toxic adenoma.

Malignant thyroid tumours 

Differentiated thyroid carcinoma - 70-80 % incidence

·       Papillary carcinoma accounts for 40 - 80 %, mainly affects younger age groups and it is not rare in children and adolescents.  They have a tendency for early metastasis to regional cervical nodes - lysogenic metastasis, in later stages, they spread hematogenously to the periphery.  Their prognosis is favourable if the therapy is initiated in the early stages.   

·       Follicular carcinoma accounts for 15 % of thyroid malignancies, it is typical of middle age and it metastasizes hematogenously, mainly to the lungs and bone.  In comparison to papillary carcinoma, the prognosis is worse.

Treatment of differentiated carcinomas is surgical with subsequent radioiodine 131I therapy in deep hypothyroidism or after a prior thyrotropin alfa stimulation, which leads to a reduction in locoregional recurrences and improves overall survival.

After surgery, thyroid hormone therapy is required.  It is administered in suppressive doses, and the duration of treatment depends on the risk stratification of the tumor at the first examination and also after treatment.

Medullary thyroid carcinoma arises from  C-cells (i.e. parafollicular cells) of the thyroid gland.  It produces calcitonin, which is detectable in serum as a marker. 

It accounts for 8% of thyroid malignancies.  It occurs sporadically, familiarly or as a part of the MEN 2 syndrome (multiple endocrine neoplasia syndrome type 2). In the familial form and MEN 2, genetic testing (RET proto-oncogene mutations) is indicated, including an inspection of family history in the direct line.  If MEN 2 is suspected, a diagnosis of possible pheochromocytoma, hyperparathyroidism, etc. should be made.

Surgery is the treatment. Tumours do not accumulate radioiodine.  Undetectable serum calcitonin and CEA levels after the surgery are a sign of a complete remission of the disease.  On the contrary, their increase is a predictor of disease progression.  Lifelong thyroid hormone replacement therapy is required after surgery.

Undifferentiated (anaplastic) thyroid carcinoma - This is the least common but a very aggressive type of thyroid cancer, which is undifferentiated in structure, grows rapidly and invasively, does not respect organ boundaries, grows into the trachea, larynx, esophagus or large neck vessels, and metastasizes early.  The chance of curing is very low, overall survival is around 6-24 months.

Almost 50 % of patients have distant metastases at the first examination.  It is classified as a stage IV T4 tumour regardless of tumour size and extent of disease. 

There is no long-term effective treatment or uniform treatment regimen.  In the treatment of anaplastic carcinoma, the treatment of choice is the external beam radiotherapy and chemotherapy based on anthracyclines, taxanes or platinum derivatives.  Surgical treatment is often indicated only to clear the airways.

Parathyroid glands - glandulaeparathyroideae

Anatomy:

There are four parathyroid glands - two upper and two lower corpuscles (glands) embedded posteriorly in both lobes of the thyroid gland.  They are lenticular, oval in shape, yellow-pink in colour and partly embedded in the thyroid gland's own connective tissue capsule - the capsula propria. 

They have a separate vascularization for each of the parathyroid glands leading from the inferior thyroid artery - a. thyroidea inferior.

The parathyroid glands have a relatively wide variation in location and number, and they can be found from the angulus mandibulae from the upper mediastinum to the heart, including the prevertebral position under the oesophagus.  Most parathyroid glands are located in a 2 cm diameter area about 1 cm above the junction of the n. laryngeusrecurrens with the inferior thyroid artery. The upper parathyroid glands are symmetrical from about 80 %, the lower parathyroid glands are symmetrical from about 70 %.   Majority of the population has 4 parathyroid glands (80-97 %).    Supernumerary parathyroid glands are found between in from 2.5 % to 20 % of the population, and a case with 8 parathyroid glands has been described (5 in 5.8% and 6 in 0.3%).  The variability in the number of parathyroid glands is common: 4 are found in 80 of people %, 3 in 14 % and 2 in 6 %.   Intrathyroidal glands are present in up to 12% of cases.

The connective septa separate into the gland from the connective tissue capsule of the parathyroid glands, thus separating the cellular trabeculae of the glandular parenchyma.  The parenchyma consists of two types of cells - principal cells, in which the parathyroid hormone is produced, and oxyphilic cells, which appear only from the 7th year of life. The main function of the parathyroid hormone is to maintain a constant level of calcium (Ca²⁺) and phosphorus (P) in the blood plasma and body fluids.  The hormone is released during hypocalcemia and it activates the conversion of osteocytes to osteoclasts, dominating bone resorption over new formation.  In the presence of vitamin D, the parathyroid hormone increases the ^Ca2+ absorption from the digestive tract and enhances renal calcium reabsorption and phosphate excretion.  The effect of the parathyroid hormone cannot be considered separately from renal synthesis of vitamin D and production of the calcitriol hormone, from thyroid secretion of calcitonin and perhaps from the thymus.  Calcium homeostasis is achieved by all these mechanisms.  Hypercalcemia inhibits parathyroid hormone synthesis.

With hypofunction of the epithelial bodies, bone and tooth formation is impaired as a consequence of low blood calcium levels.  Bones grow slowly and fractures heal poorly.  A drop in blood calcium levels impairs the transmission of impulses from nerves to muscles, increases the irritability of peripheral nerves, muscles and the brain, and can lead up to spastic convulsions - tetany with subsequent death by asphyxiation.

Hyperfunction of the epithelial corpuscles results in increased calcium and decreased phosphorus levels in the blood.  Bones become thinner, lose their strength and they bend and break easily (cystic fibrosis - ostitisfibrosacystica).  With high levels of calcium in the blood, calcium deposits - calcification - also occur in organs, e.g. blood vessels, kidneys, brain.

Examination methods:

Laboratory diagnostics is the basic examination method of hyperparathyroidism (especially the elevation of parathyroid hormone and calcium serum concentrations), clinical examinations and imaging - localization methods (neck ultrasound - topization and size of parathyroid glands, appropriate preoperative and perioperative check-up).

Functional imaging (scintigraphy) in conjunction - fusion with anatomical imaging (sonography, CT, MR) is currently considered optimum and standard.

MIBI scintigraphy - scintigraphic imaging of pathological changes of the parathyroid glands.  After an i.v. application of 99mTc MIBI (methoxyisobutylisonitrile), parathyroid adenomas and thyroid gland are imaged very quickly (within 5 minutes).  Washout of MIBI from parathyroid adenomas is slower than from a normal thyroid parenchyma.

Other methods of localization of hyperfunctioning parathyroid tissue are performed in cases of difficult topical diagnosis, especially in cases of recurrent hyperparathyroidism and before revision surgery.  These include PET/CT, venous blood catheterization to detect parathyroid hormone levels in parathyroid ectopia, especially in the upper mediastinum (bilaterally v. jugularis interna, v. cava superior et inior, v. renalis, etc.)   Interventional radiology - superselective digital subtraction angiography with eventual endovascular ablation.  Peroperative examination using methylene blue is no longer recommended due to its toxicity.

Primary hyperparathyroidism (PHPT) 

is a generalized disorder of the calcium-phosphate metabolism caused by prolonged increased secretion of parathyroid hormone.  Around 1.000 patients develop the disease in the Czech Republic every year.  In 8-10 % it concerns a hyperplasia of four parathyroid glands, in 2-3 %, an adenoma of two parathyroid glands, in 85-90 %, an adenoma of one parathyroid gland, and in <1%, a parathyroid carcinoma.  Primary hyperparathyroidism can occur at any age.  It is rare in children and less common in men than in women.  The highest frequency of the disease is in the age group of 40-60 years of age. 

Secondary hyperparathyroidism arises as a reaction of the organism to long-term hypocalcemia.  Thus, it is a physiological reaction.  In the laboratory findings, we can find low calcemia and high levels of parathyroid hormone.  There are many causes of secondary hyperparathyroidism, e.g. chronic renal failure, reduced absorption of vit.  D due to intestinal inflammation, dietary deficiency of vit.  D or calcium, etc.

The indication for parathyroid surgery is determined by an experienced endocrinologist 

1.     Hypercalcaemia > 2.75 mmol/l (or 0.25 mmol/l above the laboratory norm)

2.     Bone syndrome, non-healing ulcer disease

3.     Recurrent nephrolithiasis with urinary tract infection

Untreated PHPT leads to pathological fractures, renal insufficiency, arterial hypertension, left ventricular hypertrophy, pancreatitis, coma, cardiac arrest in systole...)

Surgical approaches:

Bilateral neck exploration 

Sternotomy

Minimally invasive approach (unilateral exploration, radio-guided approach, according to the approach: cervical approach - in the collar incision x below the level of the jugulum, axillary approach, supraareolar approach)

Surgical course:

It is recommended to dissect the NLR (nervus laryngeusrecurens) and to find its crossing with the ATI (arteria thyroidea inferior).  Most of the glands (75%) lie in this localization within a 2 cm radius.  If the glands are not found, it is recommended to continue the preparation in the thin connective tissue along the ATI and NLR on the dorsal surface of the thyroid gland, then in the adipose tissue and in the cervical processes of the thymus (28 % of the lower glands).

(MIVAP: Minimally Invasive Video-assisted Parathyroidectomy)

The procedure is performed from a 15 - 35 mm incision in the area of the jugulum, where, after releasing the thyroid lobe and inserting retractors under endoscopic control, the parathyroid gland is revised and extirpated using a harmonic scalpel (which uses the energy of high-frequency mechanical oscillations - vibrations - for its action) and a minimally invasive instrumentation with optics.  The central approach allows the revision of all parathyroid glands.  The complication rate is comparable to the conventional technique. 

Challenges of the surgery:

Number of parathyroid glands - they may be supernumerary, however, in about 10 % of cases, there are only 2 - 3

Shape of the glands - oblong, elongated, dumbbell-shaped, four-leaf clover-shaped

Size of the glands - there is no direct proportion between the size and the amount of parathyroid hormone produced

Location of the glands - often ectopic (parathyroid tissue in the mediastinum can be wherever the thymic tissue is, i.e. in the mediastinal fat outside the thymus capsule)

When performing surgery for primary hyperparathyroidism in the setting of thyroidopathy, the indication for thyroid surgery should always be established.

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