Types of Thyroidectomies and Their Indications
Types of Thyroidectomy Procedures
Thyroidectomy encompasses three main surgical approaches: total thyroidectomy (complete removal of both thyroid lobes), hemithyroidectomy/lobectomy (removal of one lobe plus isthmus), and subtotal thyroidectomy (near-complete removal leaving small thyroid remnants). 1
Total Thyroidectomy
- Complete removal of both thyroid lobes and isthmus 1
- Places both recurrent laryngeal nerves (RLNs) and all four parathyroid glands at surgical risk 1
- Requires lifelong thyroid hormone replacement 2
Hemithyroidectomy (Lobectomy + Isthmusectomy)
- Removal of one thyroid lobe and the isthmus 1
- Preserves contralateral thyroid function in most patients 1
- Lower risk profile with only one RLN and two parathyroid glands at risk 1
Subtotal Thyroidectomy
- Near-total removal leaving small thyroid remnants (typically 2-4 grams) 3
- Historically performed to preserve thyroid function 4
- Carries risk of recurrent disease in remaining tissue 5
Indications for Total Thyroidectomy
Absolute Indications for Malignant Disease
Total thyroidectomy is mandatory when any of the following high-risk features are present: 1, 6
- Tumor size >4 cm in diameter 1, 6
- Known distant metastases 1, 6
- Extrathyroidal extension 1, 6
- Cervical lymph node metastases 1, 6
- Poorly differentiated histology 1, 6
- Macroscopic multifocal disease 6
- Bilateral thyroid disease 1
- Prior radiation exposure to head/neck (Category 2B recommendation) 1
Medullary Thyroid Carcinoma (MTC)
Total thyroidectomy with bilateral central neck dissection (level VI) is required for all medullary thyroid carcinoma cases ≥1 cm or with bilateral disease. 1, 6
Hereditary MTC Syndromes:
- MEN 2B (codon 918,883 mutations): Total thyroidectomy during first year of life or at diagnosis 1
- MEN 2A (codon 609,611,618,620,630,634 mutations): Total thyroidectomy by age 5 years or when mutation identified 1
- Lower-risk RET mutations (codons 768,790,791,804,891): Prophylactic thyroidectomy may be delayed with normal annual calcitonin and ultrasound 1
Indications Allowing Either Total or Hemithyroidectomy
When ALL of the following criteria are met, either total thyroidectomy or lobectomy is acceptable (though total thyroidectomy remains most common): 1, 6
- No prior radiation exposure 1
- No distant metastases 1
- No cervical lymph node metastases 1
- No extrathyroidal extension 1
- Tumor ≤4 cm in diameter 1
- Unifocal disease 7
- Well-differentiated histology 7
Critical caveat: Even when lobectomy is technically acceptable, approximately 25% of patients with differentiated thyroid carcinoma have unrecognized tumor in the contralateral lobe that would be missed without total thyroidectomy. 8
Benign Disease Indications
Total thyroidectomy for benign disease is appropriate when: 5, 2
- Bilateral nodular disease requiring surgical intervention 2
- Graves' disease after medical treatment failure, where radical cure of hyperthyroidism is the goal 5
- Large multinodular goiter with tracheal compression or thyrotoxic evolution 5
- History of head/neck radiation with thyroid nodules (eliminates future malignancy risk) 2
- Recurrent goiter after previous subtotal thyroidectomy 5
Indications for Hemithyroidectomy/Lobectomy
Lobectomy is the preferred approach for low-risk papillary thyroid carcinoma when all favorable criteria are met: 7
- Tumor ≤4 cm 7
- No extrathyroidal extension 7
- No lymph node metastases 7
- No distant metastases 7
- Unifocal disease 7
- No prior radiation exposure 7
- No aggressive histologic variants (tall cell, columnar cell) 7
For NIFTP (noninvasive follicular thyroid neoplasm with papillary-like nuclear features), only lobectomy is needed when margins are negative and no contralateral lesion exists. 6, 7
Indications for Subtotal Thyroidectomy
Subtotal thyroidectomy has largely fallen out of favor but may be considered in specific circumstances: 3, 4
- Benign euthyroid or hyperthyroid goiter in patients who cannot tolerate lifelong hormone replacement 4
- Intraoperative findings where total thyroidectomy would place nerves or parathyroids at unacceptable risk 3
- Inexperienced surgeon performing thyroid surgery (though referral to experienced surgeon is preferable) 3
Major limitation: Subtotal thyroidectomy leaves diseased thyroid tissue with 4.5% reoperation rate for recurrent disease, and actual recurrence rates are higher when including medically managed cases. 5
Critical Surgical Considerations
Complication Rates
Total thyroidectomy should only be performed by surgeons experienced in endocrine surgery to minimize complications: 6
- Permanent hypoparathyroidism: 0-3% in experienced hands 6, 8, 5
- Permanent recurrent laryngeal nerve injury: 0-3% in experienced surgeons 6, 5, 2
- Transient hypocalcemia: 8.5% requiring temporary calcium supplementation 2
- Postoperative hemorrhage: 1.9% requiring reoperation 2
Intraoperative Decision-Making
The experienced surgeon should make the final decision between total and subtotal thyroidectomy intraoperatively based on: 3
- Clear identification of laryngeal nerves and parathyroid glands on first side 3
- Minimal bleeding and trauma during initial dissection 3
- Anatomic distortion from large lesions may necessitate subtotal approach 3
- Discovery of intracapsular or undiscovered parathyroids should prompt subtotal resection of contralateral side 3
Common Pitfalls to Avoid
Do not perform lobectomy if: 7
- Preoperative ultrasound reveals suspicious cervical lymph nodes 7
- Intraoperative findings reveal extrathyroidal extension or multifocal disease 7
- Patient has history of head/neck radiation 7
- Aggressive histologic variants suspected on preoperative cytology 7
Do not perform total thyroidectomy if: 3