Endocrine Surgery Practice Questions

Q: Most common nerve injured in ligation of inferior thyroid artery

Recurrent laryngeal nerve. **Recurrent laryngeal nerve** - The **recurrent laryngeal nerve (RLN)** runs in close proximity to the inferior thyroid artery, especially on the right side, making it highly vulnerable during ligation or thyroid surgery. - Injury to the RLN can cause **hoarseness** due to paralysis of the vocal cords, as it innervates most intrinsic laryngeal muscles. *Sympathetic trunk* - The **sympathetic trunk** lies more medially and posteriorly in the neck, generally not in the immediate surgical field for inferior thyroid artery ligation. - Injury to the sympathetic trunk typically leads to **Horner's syndrome** (ptosis, miosis, anhidrosis). *Phrenic nerve* - The **phrenic nerve** courses over the anterior scalene muscle, lateral to the thyroid gland and major vessels, making it relatively safe during standard thyroid surgery. - Damage to the phrenic nerve would result in **diaphragmatic paralysis** and respiratory compromise. *External branch of superior laryngeal nerve* - The **external branch of the superior laryngeal nerve (EBSLN)** is located more superiorly, running with the superior thyroid artery to the cricothyroid muscle. - Injury to the EBSLN would affect the **pitch of the voice** but is less commonly injured during inferior thyroid artery ligation compared to the RLN.

Q: Thyroid storm during surgery is due to?

Inadequate preoperative preparation. ***Inadequate preoperative preparation*** - **Thyroid storm** is a life-threatening exaggeration of hyperthyroidism, often triggered in patients who are **inadequately prepared** for surgery. - This typically means insufficient control of thyroid hormone levels (e.g., with antithyroid drugs, beta-blockers) prior to a surgical stressor. *Perioperative intervention* - While surgery itself is a stressor, a properly performed **perioperative intervention** on a well-prepared patient is less likely to trigger thyroid storm. - The problem is not the intervention itself, but the patient's underlying uncontrolled hyperthyroid state. *Glucocorticoid side effect* - **Glucocorticoids** are often used to treat thyroid storm, not cause it. - They help reduce peripheral conversion of T4 to T3 and provide adrenal support. *Rough handling during surgery* - While **rough handling** during thyroid surgery (e.g., excessive manipulation of the thyroid gland) can, in theory, release some thyroid hormone, it is a less significant factor in triggering thyroid storm than overall systemic hyperthyroidism. - The primary cause remains **inadequate systemic control** of thyroid hormone levels.

Q: Most commonly used approach for retrosternal goitre:-

Transcervical. ***Transcervical*** - The transcervical approach is the **most common and preferred method** for resecting retrosternal goitres, as the majority can be delivered through the **thoracic inlet**. - This approach minimizes morbidity and avoids the need for a **sternotomy** in most cases. *Transthoracic second intercostal space* - This approach is typically reserved for **mediastinal masses** or procedures requiring direct access to the **pleural cavity**, which is generally not necessary for retrosternal goitres. - It would involve a more invasive incision than typically required for a goitre that can be delivered transcervically. *Axillary approach* - The axillary approach is primarily used for **lymph node dissection** in breast cancer or for certain **thoracoscopic procedures**, not for accessing the thyroid gland for retrosternal goitre removal. - Its anatomical location does not provide adequate exposure to the **cervical and mediastinal structures** involved in a retrosternal goitre. *Trans-sternal through anterior mediastinum* - A trans-sternal approach (sternotomy) is a **major surgical procedure** typically reserved for very large, irreducible retrosternal goitres that have significant **mediastinal extension** or are adherent to surrounding structures. - It is avoided whenever possible due to increased morbidity and longer recovery compared to the transcervical approach, making it less commonly used overall.

Q: What is the name of this technique for palpation of thyroid where a thumb is placed on the lateral side of trachea and patient is swallowing?

Crile method. Crile method - The Crile method for thyroid palpation involves placing a thumb on one side of the trachea and gently pushing the thyroid lobe to the opposite side to better assess it during swallowing. - This technique helps to stabilize the gland and makes it easier to feel for nodules or enlargement. Pizzilo method - There is no widely recognized or standardized thyroid palpation technique called the Pizzilo method in medical literature. - This term is therefore incorrect in the context of thyroid examination. Lahey's method - Lahey's method for thyroid examination involves standing behind the patient and palpating the thyroid gland as the patient swallows, using both hands [1]. - It differs from the Crile method by typically using both hands from behind the patient, rather than focusing on a single thumb on the lateral side of the trachea [1]. Kocher's test - Kocher's test is primarily used to assess for exophthalmos in patients with Graves' disease, by observing the involuntary retraction of the upper eyelid when gazing downwards. - It is not a technique for the palpation of the thyroid gland itself.

Q: Most common cause of recurrent laryngeal nerve palsy is:

Thyroid surgery. ***Thyroid surgery*** - **Iatrogenic injury** during **thyroid surgery** (thyroidectomy) is the most common cause of recurrent laryngeal nerve palsy due to the proximity of the nerve to the thyroid gland. - The nerve can be stretched, ligated, or transected during the procedure, leading to vocal cord paralysis. *Mediastinal tumors* - While mediastinal tumors can cause recurrent laryngeal nerve palsy by **compressing or invading the nerve**, this is less common than iatrogenic injury during thyroid surgery. - The left recurrent laryngeal nerve is particularly vulnerable due to its longer course through the mediastinum. *Bronchogenic carcinoma* - **Bronchogenic carcinoma**, especially those in the apex of the lung or near the aortic arch, can invade or compress the recurrent laryngeal nerve, causing palsy. - However, this is primarily a cause in specific, advanced cancer cases and not the most common overall cause. *Pancoast tumor* - A **Pancoast tumor** (a type of bronchogenic carcinoma in the lung apex) can cause recurrent laryngeal nerve palsy, particularly on the left side, due to local invasion. - While a specific cause of nerve palsy, it is a less frequent cause compared to surgical injury to the thyroid gland.

Q: Which is a known complication of thyroid surgery?

Hypocalcemia. ***Hypocalcemia*** - This is a common complication due to potential **accidental removal** or **damage to the parathyroid glands** during thyroidectomy. - The parathyroid glands regulate **calcium levels**, and their impairment leads to decreased parathyroid hormone (PTH) secretion, causing hypocalcemia. *Hypercalcemia* - This is an **elevated calcium level**, which is generally not a complication of thyroid surgery itself. - It would more commonly be associated with conditions like **primary hyperparathyroidism**. *Hypoglycemia* - This is a condition of **low blood glucose**, which is not directly related to thyroid surgery. - It is typically associated with conditions affecting **insulin regulation**, such as diabetes mellitus. *Hyperkalemia* - This refers to **elevated potassium levels** in the blood, which is not a typical complication of thyroid surgery. - It is more commonly seen in conditions like **renal failure** or certain medication side effects.

Q: Which of the following steps in thyroid surgery is least likely to result in hoarseness of voice?

Division of strap muscles. ***Division of strap muscles*** - Dividing the **strap muscles** (sternohyoid, sternothyroid, omohyoid) provides surgical access to the thyroid gland but does not directly involve structures critical for vocal cord function. - While it may cause temporary **neck discomfort** or altered neck contour, it is least likely to lead to hoarseness. *Ligation of superior thyroid artery* - Ligation of the **superior thyroid artery** occurs in close proximity to the **external laryngeal nerve**, a branch of the superior laryngeal nerve. - Damage to the external laryngeal nerve can cause subtle voice changes due to **cricothyroid muscle paralysis**, impacting pitch. *Removal of the tubercle of Zuckerkandl* - The **tubercle of Zuckerkandl** is a posterior extension of the thyroid gland, often lying close to the **recurrent laryngeal nerve**. - Its removal requires careful dissection in an area where the recurrent laryngeal nerve is vulnerable to **traction or direct injury**, which can cause hoarseness. *Dissection of Beahrs triangle* - **Beahrs triangle** is an anatomical landmark formed by the common carotid artery, inferior border of the thyroid lobe, and the recurrent laryngeal nerve. - Dissection within this triangle carries a high risk of **recurrent laryngeal nerve injury**, leading to vocal cord paralysis and significant hoarseness.

Q: Which nerve is most likely injured during a thyroidectomy?

Recurrent laryngeal. ***Recurrent laryngeal*** - The **recurrent laryngeal nerves** are highly susceptible to injury during thyroidectomy due to their close anatomical proximity to the **thyroid gland** and their relatively superficial course within the operative field. - Injury to these nerves can lead to **vocal cord paralysis**, resulting in **hoarseness** or, in cases of bilateral injury, severe airway compromise. *Hypoglossal* - The **hypoglossal nerve** (CN XII) innervates the muscles of the tongue and is located more superiorly and medially, well outside the typical dissection planes for a thyroidectomy. - Damage to this nerve would primarily affect **tongue movement** and speech articulation, symptoms not commonly associated with thyroid surgery complications. *Phrenic nerve* - The **phrenic nerve** innervates the diaphragm and is situated deep in the neck and thorax, far from the thyroid surgical field. - Injury during thyroidectomy is extremely rare and would lead to **diaphragmatic paralysis**, causing respiratory difficulties. *Superior laryngeal* - The **superior laryngeal nerve** descends alongside the superior thyroid artery and typically divides into internal and external branches; the **external branch** is at risk during ligation of the superior thyroid pedicle. - While it can be injured, the **recurrent laryngeal nerve** is more frequently and severely affected, particularly its motor function to the intrinsic laryngeal muscles, which is most critical for voice production.

Question 1

Most common nerve injured in ligation of inferior thyroid artery

Accepted Answer

Recurrent laryngeal nerve

Answer

Sympathetic trunk

Answer

Phrenic nerve

Answer

External branch of superior laryngeal nerve

Question 2

Thyroid storm during surgery is due to?

Accepted Answer

Inadequate preoperative preparation

Answer

Perioperative intervention

Answer

Glucocorticoid side effect

Answer

Rough handling during surgery

Question 3

Which of the following statements is true regarding retrosternal goiters?

Accepted Answer

Most retrosternal goiters can be removed through a neck incision

Answer

Majority of the goiters derive their blood supply from mediastinal vessels

Answer

Sternal incision is required in all cases

Answer

Surgery is performed only if the patient is symptomatic

Question 4

Most commonly used approach for retrosternal goitre:-

Accepted Answer

Transcervical

Answer

Transthoracic second intercostal space

Answer

Axillary approach

Answer

Trans-sternal through anterior mediastinum

Question 5

What is the name of this technique for palpation of thyroid where a thumb is placed on the lateral side of trachea and patient is swallowing?

Accepted Answer

Crile method

Answer

Pizzilo method

Answer

Lahey's method

Answer

Kocher's test

Question 6

Most common cause of recurrent laryngeal nerve palsy is:

Accepted Answer

Thyroid surgery

Answer

Mediastinal tumors

Answer

Bronchogenic carcinoma

Answer

Pancoast tumor

Question 7

A 45-year-old develops dysphagia 3 months post thyroidectomy. Most likely cause?

Accepted Answer

Adhesions

Answer

Recurrent tumor

Answer

RLN palsy

Answer

Esophageal injury

Question 8

Which is a known complication of thyroid surgery?

Accepted Answer

Hypocalcemia

Answer

Hypercalcemia

Answer

Hypoglycemia

Answer

Hyperkalemia

Question 9

Which of the following steps in thyroid surgery is least likely to result in hoarseness of voice?

Accepted Answer

Division of strap muscles

Answer

Ligation of superior thyroid artery

Answer

Removal of the tubercle of Zuckerkandl

Answer

Dissection of Beahrs triangle

Question 10

Which nerve is most likely injured during a thyroidectomy?

Accepted Answer

Recurrent laryngeal

Answer

Hypoglossal

Answer

Phrenic nerve

Answer

Superior laryngeal

Endocrine Surgery — MCQs

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