Endocrine surgery

What is Endocrine Surgery (EC)?

Endocrine surgery (ES) is the area of surgery that deals with the treatment of diseases affecting those organs whose job is to produce hormones into the blood.

As far as our speciality is concerned, there are three organs that usually present pathologies on which surgeons have to act: the thyroid gland, the parathyroid glands and the adrenal gland.

THYROID GLAND

The thyroid gland is shaped like a butterfly and is divided into two small lobes connected by an isthmus (the lobes would be the wings and the isthmus would be the body of the butterfly), located at the front of the neck, just in front of the trachea (which is the main airway). Its task is to produce thyroid hormone, which is a very important hormone as it is responsible for the proper balance of many functions and whose imbalance can become apparent in various organs of our anatomy. It also produces another hormone called calcitonin, which, together with parathyroid hormone, is responsible for controlling calcium in the blood.

What is a goitre?

When the thyroid gland enlarges, it is called a goitre; this enlargement takes the form of lumps called nodules, so the goitre may be a single nodule (a solitary thyroid nodule) or several nodules, which is called a multinodular goitre.

When should a goitre be operated on?

The presence of goitre, which is a very common problem, does not imply that the patient should be operated on. The criteria for operating on a goitre situation are well defined in the medical literature:

The presence of an obvious aesthetic deformity. If the goitre is visible to the naked eye, it generates an asymmetry in the diameter of the neck or a thickening of the neck that leads the patient to request surgery. Similarly, the sudden growth of a thyroid nodule in a short period of time is an absolute indication for surgery due to the risk of malignant transformation.
The presence of local symptoms. By local symptoms we mean when the enlargement of the thyroid gland compresses the neighbouring structures, which are the airway (trachea), the recurrent nerve (responsible for our ability to speak) and the upper digestive tract (oesophagus). Thus, difficulty in swallowing and deglutition, a recent change in the tone of voice (especially hoarseness) and the sensation of occupation of the neck always define the need to operate on a goitre patient.
When fine needle aspiration (FNA) of a thyroid nodule is suspicious or indicates the presence of a thyroid tumour, either follicular or papillary, which are the most frequent.
The presence of associated hyperthyroidism, either in a single nodule (defined as toxic adenoma) or in a multinodular goitre (defined as Plummer's disease).

What is an FNA?

FNA, or fine needle aspiration-puncture, consists of puncturing a thyroid nodule from the outside and under ultrasound control in order to obtain an early sample for anatomical-pathological analysis to determine whether it is benign or malignant in nature.

What is hyperthyroidism?

Hyperthyroidism is a situation that occurs when there is an excess production of hormone by the thyroid gland. It is manifested by the presence of symptoms such as weight loss, irritability, nervousness, increased heart rate, weight loss, insomnia and poor tolerance to heat; in the analysis, we will see high values of thyroid hormones (T3 and L-T4) and very low or slow TSH.

Although medically treatable (antithyroid drugs), the best treatment for patients with a thyroid nodule or multinodular goitre is surgery, as it allows definitive treatment of the cause of hyperthyroidism and an analysis of the thyroid that is resected.

An exception to this rule is the disease known as Graves-Basedow, in which hyperthyroidism has an autoimmune origin (i.e. it is our own body that attacks us) and there is an effective alternative to surgery, which is pharmacological control or even ablation of the thyroid tissue with administration of Radioactive Iodine; the Endocrinology specialist will explain to the patient the pros and cons of each treatment, involving him/her in the final decision.

What should I know about thyroid cancer?

Hypothyroidism is the cessation, usually permanent, of thyroid function, with very characteristic symptoms such as weight gain, tendency to sleep, tiredness despite little physical activity, bradycardia and lethargy. Blood tests will show very low hormone levels in the blood and very high TSH values.

It is a relatively frequent situation in our environment and its treatment is medical, consisting of the oral administration of thyroid hormone (Levothyroxine). The only situations requiring surgical treatment in patients with hypothyroidism are those associated with a goitre condition with the indications explained above.

When should a goitre be operated on?

Thyroid cancer is perhaps the most "benign" of all human cancers. Why do we say this? Well, because the 90% belong to the group of well-differentiated cancers (papillary or follicular) and their clinical course is relatively indolent, since:

Most are cured simply by surgery performed by a surgeon experienced in endocrine surgery.
When they do reproduce, they most often do so in the neck in the form of lymph node disease, and surgery is again the option that may allow treatment with curative intent.
There is no place or room for chemo and radiotherapy, which allows these patients to be spared the side effects and deterioration of quality of life secondary to these treatments.
When there is distant metastasis, there is the possibility of treatment with Radioactive Iodine, which is very effective and quite harmless.
With the combined treatments, survival of thyroid cancer patients is, respectively, 95% and 80% at 25 years for papillary and follicular cancers.

However, 10% of thyroid cancers remain in the medullary or anaplastic variant, which have a much worse prognosis due to the high risk of reproduction of the former and the low chance of curative surgery in the latter.

What types of interventions can be performed on the thyroid gland?

There are two common procedures performed on the thyroid: total thyroidectomy and haemithyroidectomy, usually including the isthmus. Total thyroidectomy is the most frequently performed and is indicated in suspected thyroid cancer, in multinodular goitres and in solitary nodules with poor underlying thyroid function or associated hypothyroidism.

Haemithyroidectomy is indicated only in cases of a single nodule with good baseline thyroid function and no diagnostic FNA for cancer, and consists of resection of the diseased lobe and the thyroid isthmus. The lobe on the other side is preserved intact.

Upon preoperative diagnostic confirmation of thyroid cancer, a lymph node clearance (called "lymphadenectomy") of the central area of the neck where the thyroid is located should be performed in conjunction with total thyroidectomy; if enlarged lymph nodes are palpated on the sides of the neck or ultrasound reveals a pathological lymph node size, a lymph node clearance should be performed at this level in order not to leave residual active disease. The standard incision used for thyroidectomy is a small transverse neck incision of 5-7 cm, which is closed with intradermal sutures (no stitches on the outside) and usually without drainage. Patients are usually discharged in less than 24 hours for most patients, and all within 48 hours.

What are the complications of thyroid surgery?

Lhe potential complications associated with thyroid surgery are essentially threefold:

Suffocating haematoma, which occurs in <1% of cases. It consists of the occupation of the central space of the neck where the thyroid was lodged by blood under tension, compressing the airway and potentially causing asphyxia. Its treatment is urgent decompression in the operating theatre, opening the wound and cleaning the haematoma. It is common in these cases to have to associate a tracheostomy, which is almost always temporary.
Injury to the recurrent nerves. The recurrent or inferior laryngeal nerves are responsible for our ability to speak because they force the vocal cords to open and the passage of air through them causes the sounds that make up our speech. They are hidden behind each thyroid lobe, their size is less than 1 mm in diameter and they are often traumatised during manipulation of the thyroid gland in surgery. Such trauma sometimes results in temporary paralysis (or paresis) which may last 2-8 weeks before complete recovery and which we observe as more or less marked hoarseness in the immediate postoperative period. This complication occurs in less than 10% of cases and is always related to the extent of surgery and the size of the goitre or cancer being treated. If the two recurrent nerves are affected, a tracheostomy may be necessary as the vocal cords are centrally located and no air can pass through them. Although the surgeon's experience is the most scientifically proven way to prevent their injury, it may be useful to locate and control them with special techniques during surgery.
This is the presence of depressed function of the parathyroid glands in the immediate postoperative period as a consequence of inadvertent injury or simply stunning of the parathyroid glands during surgery. The parathyroid glands exist in number of 4 and are located 2 around (para-) each thyroid (-thyroid) lobe and are responsible for the maintenance of adequate blood calcium levels. Not damaging them should be a goal of thyroid surgery, but sometimes proximity makes their manipulation and devascularisation unavoidable, which manifests in the immediate postoperative period as low blood calcium levels (tingling in the mouth and at the tips of the hands and feet, numbness and stiffness of the wrists and ankles). It is treated with calcium and vitamin D for as long as it takes for the parathyroids to recover normal function in transient cases (12-16%) and for life when the damage is permanent (2-4%).

What happens to the function of the thyroid gland when I have surgery?

Obviously, if the surgery performed is a total thyroidectomy, the body's ability to produce thyroid hormone disappears and the patient must take replacement therapy. For many years, thyroid hormone has been marketed under the generic name of Levothyroxine in the form of small, easy-to-take tablets. Regular check-ups with the endocrinology specialist will allow the appropriate dose to be adjusted for each patient.

When the surgery performed is a partial thyroidectomy or haemithyroidectomy, two situations can occur:

The remaining lobe is able to produce enough hormone for good function; in this case, the patient needs analytical controls every 4-6 months to assess active thyroid function.
That the remaining lobe does not have the reserve to supply all the thyroid function, which will require the administration of a supplementary dose that will also be adjusted in the controls by Endocrinology.

PARATHYROID GLANDS

Lhe parathyroid glands are 4 in number, and as their name suggests they are located in the vicinity of the thyroid gland, posterior to and just to the side of each of the upper and lower poles of each side.

They are between 3-6 mm in size and their function is to regulate calcium metabolism in the blood, and they do this by producing parathyroid hormone, also called parathyroid hormone (PTH).

What is primary hyperparathyroidism?

Primary hyperparathyroidism consists of excess PTH production, which leads to calcium mobilisation from the bones into the blood. It manifests with symptoms such as repeated renal colic, high blood pressure and early osteoporosis due to decalcification. In blood tests, it manifests as hypercalcaemia (high levels of calcium in the blood), hypercalciuria (high levels of calcium in the urine) and elevated PTH values in the blood.

90% of primary hyperPTH cases are due to a parathyroid adenoma. An adenoma is an autonomous and uncontrolled growth of one of the parathyroid glands, resulting in exaggerated PTH levels and the symptoms described above. In the remaining 10%, primary hyperPTH is due to asymmetric growth of all 4 glands, a phenomenon known as hyperplasia and usually located within a multiple endocrine neoplasia syndrome. The diagnosis of primary hyperPTH requires, prior to surgery, localisation studies of the diseased gland, which are cervical ultrasound and subtraction scintigraphy with Technetium Sesta-MIBI.

What is the treatment of primary hyperparathyroidism?

It is well established in the medical literature that one of the factors determining success in the surgical treatment of primary hyperPTH is that the intervention is performed by a surgeon with accredited experience in endocrine surgery.

The treatment for hyperPTH is surgery, which aims to resect the diseased gland(s) to normalise blood calcium levels. In cases of well-localised adenoma, the minimally invasive approach is performed through a small lateral incision of 3-4 cm that allows direct access to the affected gland; recovery is usually immediate, it is a surgery with few potential complications and patients are discharged home in less than 24 hours. When hyperplasia is suspected or there is no diagnosis of localisation, a standard central cervical incision (as used for thyroid surgery) is made and both sides are explored for pathological gland(s); the minimum intervention for parathyroid hyperplasia will consist of resection of at least 3 parathyroid glands and a half (subtotal parathyroidectomy).

When performed according to these criteria, the success rate (understood as normalisation of calcium and PTH levels in the blood) is as high as 95-98% of cases.

Intraoperative blood calcium determination provides almost immediate information on whether the operation has been successful.

Are all these techniques performed laparoscopically?

Minimally invasive surgery is one of the greatest advances in medicine. When performed in the abdominal cavity, it is called laparoscopic surgery. It consists of operating using specific instruments and an optic inserted into the abdomen through a high-resolution microcamera, which transmits the image to a television monitor. To perform this surgical technique, small wounds of between half a centimetre and one centimetre are used.

The advantages of performing vertical gastrectomy and gastric bypass laparoscopically are:

Rapid post-operative recovery
Rapid recovery of bowel function
Pain reduction
Reduced risk of developing eventrations

What are recurrent and persistent hyperparathyroidism?

Both situations imply the existence of elevated PTH levels in the blood after a previous surgery that was supposed to be successful. Persistence indicates that calcium levels have either never normalised or, after a period of normocalcaemia, are elevated again within a period of less than 6 months; if this period is longer than 6 months, hyperPTH is defined as recurrent.

In both cases, the patient should be re-evaluated by the endocrinology specialist, imaging studies repeated (a CT scan may provide complementary information) and, in almost all cases, a new cervical surgical procedure considered.

What is secondary hyperparathyroidism?

Secondary hyperPTH is the elevation of PTH levels in the blood as a consequence of the activation of all the parathyroid glands (hyperplasia) simultaneously as a response to the alterations in metabolism that occur in patients with chronic renal failure. Hypercalcaemia is very difficult to control and the only possible treatment in severe cases is surgery, consisting of a subtotal parathyroidectomy. It is always the nephrology specialist who must establish the need to operate or not.

What is tertiary hyperparathyroidism?

When the cause of chronic renal failure and secondary hyperPTH is corrected by renal transplantation, it is common for the hyperplasia of the parathyroid glands to be corrected and return to normal activity. However, in some patients, one or more glands have been stimulated to such a degree that their hyperactivity remains despite correction of the causative problem. In this case, we are dealing with tertiary hyperPTH, the only treatment for which is surgery.

ADRENAL GLANDS

The The adrenal glands (ASGs) are two small structures that sit like "caps" on top of each kidney and play an important role in our body's hormone balance. Each GSR has a central area called the medulla, where adrenaline is produced, and a peripheral part called the cortex, where corticosteroids, aldosterone and part of the sex hormones, both male and female, are basically produced.

What hormones are produced in the adrenal gland?

The catecholamines (adrenaline and its precursor, noradrenaline (NA)), are responsible for maintaining adequate levels of blood pressure (BP), heart rate and the body's response to stressful situations. It also collaborates with insulin, produced in the pancreas, in maintaining adequate blood sugar levels.
The corticosteroids are produced in the so-called fascicular zone of the adrenal cortex, and are responsible for many organ functions, including maintenance of AT, stress response and control of inflammatory processes, so they are an important part of the defence system.
The aldosterone is the hormone produced in the glomerular area of the cortex, and its main task is also to help maintain an adequate AT by retaining water and salt in the kidney.
The sex steroid hormones are produced in the reticular area of the cortex, and are responsible for the development of the so-called secondary sexual characteristics (body hair, deepening of the voice, development of external genitalia...) either directly or through joint action with the gonads (testicles and ovaries).

What diseases may require a GSR operation?

The GSR diseases that will require removal are those in which there is an excess of GSR production or in which there is, with normal functioning, an increase in the size of the GSR that suggests a malignant tumour.A) Excess hormone production is caused by uncontrolled autonomous growth of a group of cells in one of the previously defined layers (normally known as an adenoma), and generates well-defined syndromes:

Cushing's syndromewhen there are elevated levels of glucocorticoids due to overproduction from the fascicular layer.
Conn's syndromewhen it is the glomerular area that produces excess aldosterone.
Virilisation syndromeswhen very high levels of sex steroids are produced from the reticular layer.
PheochromocytomaThe tumours that occur in the adrenal medulla and produce high levels of catecholamines, manifesting as tachycardia and severe hypertensive crises.

The 90% of these cases of excess production will be due to benign tumours, and only in 10% of cases will it be a functioning adrenal carcinoma or pheochromocytoma.B) The great development and growth of imaging tests such as CT and MRI, which are increasingly used, has made it possible to identify tumours in the adrenal glands that do not produce any hormone and are called "incidentalomas". The most important thing about these incidentalomas is their size; when they are smaller than 3-4 cmt, they only require periodic follow-up imaging studies; however, when they are larger than 4-5 cm they have a 10-15% risk of being malignant and surgery is recommended. However, imaging tests can help to discern which pathology we are dealing with and thus discern the best treatment.

What should I know about adrenal cancer?

Adrenal cancer is rare but extremely aggressive. In less than half of the cases there is hormone production which allows earlier diagnosis, but in the rest of the cases when it is diagnosed it is already a large mass that has often infiltrated (or engulfed) neighbouring tissues or organs. Since there is no effective chemo- or radiotherapy, aggressive surgery by an experienced oncological surgeon is the mainstay of treatment.

What does adrenal gland surgery consist of?

Surgery involves the removal of the affected adrenal gland, and this must nowadays always be done systematically laparoscopically; 3-4 incisions of 5 or 10 mm are made and the patient is placed in the lateral decubitus position.

The only discussion is in cases of suspected malignancy or in cases where the tumour is larger than 8-9 cm, where many surgeons prefer the open approach for the safety of the patient.
Laparoscopy allows for very rapid functional recovery, with discharge in 24-48 hours and a return to normal life within 12-14 days. Postoperative complications are rare.