Teach me thyroidectomy Topic of surgery Give full detail but in concise form
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Thyroidectomy: concise surgical overview
Thyroidectomy is surgical removal of part or all of the thyroid gland. It is performed by trained endocrine/head-and-neck surgeons under general anesthesia.
Types
| Operation | What is removed | Typical use |
|---|---|---|
| Hemithyroidectomy / lobectomy | One lobe plus isthmus | Solitary indeterminate/suspicious nodule, unilateral small cancer, symptomatic unilateral goitre |
| Total thyroidectomy | Entire gland | Bilateral multinodular goitre, Graves' disease, most differentiated thyroid cancers |
| Completion thyroidectomy | Remaining lobe after prior lobectomy | Cancer or pathology requiring total removal |
| Subtotal thyroidectomy | Most, but not all gland | Now uncommon due to recurrence risk |
Indications
- Confirmed or suspected thyroid malignancy
- Large multinodular goitre causing pressure symptoms: dysphagia, dyspnea, tracheal compression
- Toxic multinodular goitre or toxic adenoma when definitive surgical treatment is appropriate
- Graves' disease when medications or radioiodine are unsuitable, contraindicated, or declined
- Enlarging, symptomatic, cosmetic, or indeterminate thyroid nodules
Key anatomy to know
-
Recurrent laryngeal nerve (RLN)
Runs near the tracheoesophageal groove and enters the larynx near Berry's ligament. Injury causes hoarseness and vocal-cord paresis. -
External branch of superior laryngeal nerve (EBSLN)
Closely related to superior thyroid vessels. Injury reduces ability to produce high-pitched voice and voice projection. -
Parathyroid glands
Usually four, on the posterior thyroid surface. Must be preserved with blood supply to avoid postoperative hypocalcemia. -
Superior thyroid artery
Ligate close to the thyroid capsule to protect the EBSLN. -
Inferior thyroid artery branches
Preserve branches supplying parathyroids. Identify RLN before dividing tissue near it. -
Berry's ligament
Dense attachment of thyroid to trachea. A high-risk area for RLN injury.
Preoperative assessment and preparation
- History: compressive symptoms, thyrotoxicosis, prior neck surgery/radiation, family history, voice change.
- Examination: thyroid size, retrosternal extension, cervical lymph nodes, vocal quality.
- Investigations:
- TSH and free T4, with T3 if needed
- Neck ultrasound and fine-needle aspiration cytology where indicated
- Flexible laryngoscopy if preoperative voice change, cancer, prior neck/chest surgery, or high-risk setting
- Serum calcium, vitamin D, renal function
- CT neck/chest without iodinated contrast if substernal goitre or tracheal compression is suspected
- Hyperthyroidism must be controlled before elective surgery with antithyroid drugs, beta-blockade, and sometimes iodine preparation. Operating on uncontrolled thyrotoxicosis risks thyroid storm.
- Explain risks and obtain consent, including scar, bleeding, nerve injury, hypocalcemia, lifelong hormone replacement after total thyroidectomy, and possible completion surgery.
Operative steps: conventional open thyroidectomy
1. Position and incision
- General anesthesia, usually with endotracheal tube.
- Supine with a shoulder roll, neck extended gently.
- A low transverse collar incision is made about 2 fingerbreadths above the sternal notch.
2. Exposure
- Divide skin, subcutaneous tissue, and platysma.
- Raise superior and inferior subplatysmal flaps.
- Open the midline between strap muscles.
- Retract or divide strap muscles selectively for large goitres.
3. Mobilize the thyroid lobe
- Expose the thyroid capsule.
- Divide the middle thyroid vein, if present, to mobilize the lobe medially.
- Carefully dissect laterally and posteriorly while staying close to the thyroid capsule.
4. Superior pole dissection
- Mobilize the upper pole.
- Individually ligate branches of the superior thyroid vessels close to the gland.
- This protects the EBSLN.
5. Parathyroid preservation
- Identify superior and inferior parathyroid glands.
- Preserve each gland's vascular pedicle.
- If a gland becomes devascularized or is accidentally removed, confirm parathyroid tissue and autotransplant small fragments into sternocleidomastoid muscle, according to local protocol.
6. Identify and preserve the RLN
- Identify the RLN in a reliable location, commonly low in the tracheoesophageal groove.
- Trace it toward laryngeal entry.
- Avoid traction, thermal spread, clamping, and blind ligation.
- Intraoperative nerve monitoring may assist identification but does not replace meticulous visual dissection.
7. Divide Berry's ligament and remove lobe
- Free the thyroid carefully from the trachea at Berry's ligament.
- This is the most nerve-vulnerable part of the operation.
- Remove the lobe and isthmus. Repeat on the opposite side for total thyroidectomy.
8. Hemostasis and closure
- Check the thyroid bed carefully for bleeding, often after Valsalva maneuver.
- Drains are not routinely required in uncomplicated cases.
- Reapproximate strap muscles if divided, close platysma and skin.
Principles of safe thyroidectomy
- Stay close to the thyroid capsule.
- Identify the RLN visually before dividing adjacent tissue.
- Preserve parathyroids and their blood supply.
- Ligate superior-pole vessels close to the gland.
- Achieve meticulous hemostasis because a neck hematoma can rapidly compromise the airway.
- Do not perform blind clamping in the thyroid bed.
Complications
Early
| Complication | Features | Action |
|---|---|---|
| Neck hematoma | Neck swelling, pressure, dysphagia, stridor, respiratory distress | Emergency wound opening and airway management |
| RLN injury, unilateral | Hoarseness, weak voice, aspiration | Laryngoscopy, speech therapy, possible medialization procedure |
| RLN injury, bilateral | Stridor, airway obstruction | Urgent airway management, may require tracheostomy |
| EBSLN injury | Loss of high pitch, vocal fatigue | Usually diagnosed clinically or by laryngoscopy |
| Hypocalcemia | Perioral tingling, cramps, tetany, prolonged QT | Check calcium/PTH, give calcium with or without calcitriol |
| Thyroid storm | Fever, tachycardia, agitation, heart failure | ICU-level emergency management |
| Seroma/infection | Swelling, discharge, fever | Drainage or antibiotics if indicated |
Late
- Permanent hypoparathyroidism
- Persistent voice change
- Hypertrophic scar or keloid
- Hypothyroidism after hemithyroidectomy in some patients
- Recurrence after subtotal thyroidectomy
Postoperative care
- Observe for bleeding and airway compromise, especially in the first 6 to 24 hours.
- Assess voice soon after recovery.
- Check calcium, and often parathyroid hormone, after total thyroidectomy or high-risk surgery.
- Oral calcium and calcitriol may be prescribed if biochemical or symptomatic hypocalcemia occurs.
- Histopathology determines any need for further cancer treatment.
- After total thyroidectomy: lifelong levothyroxine is required.
- After hemithyroidectomy: check TSH at approximately 6 to 8 weeks; some patients need levothyroxine.
Thyroid cancer note
For thyroid cancer, the extent of surgery depends on tumor size, pathology, nodal disease, extrathyroidal extension, contralateral disease, patient factors, and whether radioactive iodine treatment is planned. Some low-risk cancers can be treated adequately with lobectomy, while higher-risk disease often needs total thyroidectomy with appropriate lymph-node dissection.
One-line exam summary
Thyroidectomy is a capsular dissection operation in which safe preservation of the recurrent laryngeal nerves, external laryngeal nerves, parathyroid glands, and meticulous hemostasis are the central principles.
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