Difference Between Near-Total and Subtotal Thyroidectomy
Near-total thyroidectomy leaves thyroid tissue remnants less than 1 cm, while subtotal thyroidectomy deliberately leaves tissue remnants of 1 cm or greater in the thyroid bed. 1
Anatomic Definitions
Near-total thyroidectomy (NTT):
- Leaves minimal thyroid tissue remnants measuring less than 1 cm in the thyroid lodge 1
- Represents an intentional near-complete removal with only microscopic to small macroscopic remnants 1
- Associated with a low rate of disease recurrence 1
Subtotal thyroidectomy (ST):
- Deliberately leaves a portion of thyroid tissue measuring 1 cm or greater in the thyroid bed 1
- Results in considerably higher recurrence rates compared to near-total or total thyroidectomy 1
- Historically performed to theoretically reduce complications by preserving parathyroid blood supply and protecting the recurrent laryngeal nerve 2
Complication Profile Comparison
The complication rates differ significantly between these approaches:
- Permanent recurrent laryngeal nerve injury: 3% after total/near-total thyroidectomy versus 1.9% after subtotal thyroidectomy 3
- Permanent hypoparathyroidism: 2.6% after total/near-total thyroidectomy versus 0.2% after subtotal thyroidectomy 3
- Temporary hypocalcemia: 5.4% immediately post-total thyroidectomy, with only 0.5% remaining permanent at one year 3, 4
However, these complication differences become negligible when surgery is performed by experienced, high-volume surgeons (>100 cases/year: 4.3% overall complication rate versus <10 cases/year: 17.2% complication rate). 4, 5
Clinical Implications for Disease Management
For malignant disease:
- Total or near-total thyroidectomy is strongly preferred because it enables radioactive iodine ablation therapy for residual microscopic disease 6, 2
- Subtotal thyroidectomy leaves too much tissue for effective radioiodine scanning and treatment 6
- Completion thyroidectomy is often required after subtotal procedures when cancer is diagnosed, subjecting patients to reoperation risks 6, 7
For benign disease:
- Subtotal thyroidectomy has substantially higher recurrence rates requiring reoperation 1, 7
- Near-total thyroidectomy provides better disease control while maintaining acceptable complication rates 1
Practical Surgical Reality
An important caveat: Even when surgeons intend to perform "total thyroidectomy," imaging studies reveal that thyroid tissue remnants remain in 33.3% of cases—with 11.76% actually representing near-total thyroidectomy (<1 cm remnants) and 21.57% representing subtotal thyroidectomy (≥1 cm remnants). 1 This means the distinction between these procedures may sometimes reflect surgical outcome rather than surgical intent.
The experienced surgeon can minimize complications with any extent of resection, but may choose to leave small amounts of tissue strategically to protect parathyroid blood supply or recurrent laryngeal nerve anatomy in selected high-risk cases. 2