Minimally Invasive Thyroidectomy
For selected low-risk thyroid disease, minimally invasive video-assisted thyroidectomy (MIVAT) is a safe and effective alternative to conventional open thyroidectomy, offering equivalent oncologic outcomes with superior cosmetic results and reduced postoperative pain, provided strict patient selection criteria are met.
Patient Selection Criteria
The success of minimally invasive thyroidectomy depends critically on appropriate patient selection:
- Nodule size ≤30 mm 1
- Thyroid volume <20 mL 1
- No thyroiditis present 1
- No previous neck surgery or irradiation 1
- Absence of invasive features (no fixation to adjacent structures, no vocal cord paralysis, no rapid growth) 2
Surgical Approach Options
MIVAT Technique (Preferred for Appropriate Candidates)
- Uses a 15-20 mm central incision approximately 2 cm above the sternal notch 3, 1
- Performed as a gasless procedure using conventional and endoscopic instruments with video assistance 1
- Requires small conventional retractors, ultrasonic scalpel, and 5-mm laparoscope 3
Lobectomy vs Total Thyroidectomy
Lobectomy is recommended for selected low-risk tumors (T1a-T1b-T2, N0) rather than routine total thyroidectomy 4. This applies to:
- Unifocal papillary microcarcinomas (≤10 mm) with no extracapsular extension or lymph node metastases 4
- Selected low-risk differentiated thyroid cancers 4
Expected Outcomes
Operative Times
- Mean 35 minutes (range 20-70 minutes) for unilateral lobectomy 3
- Mean 58 minutes (range 35-90 minutes) for bilateral thyroidectomy 3
- Operating times are longer than conventional surgery but acceptable 5
Complication Rates (Comparable to Conventional Surgery)
- Permanent recurrent laryngeal nerve palsy: 0.8-1.7% 3, 6
- Transient recurrent laryngeal nerve palsy: 2.3-2.4% 3, 6
- Permanent hypoparathyroidism: 0.2% 3, 6
- Transient hypocalcemia: 3.0-7.2% 3, 6
- Bleeding requiring reoperation: 0.2% 3, 6
- No wound infections or bilateral nerve injuries 3
Advantages Over Conventional Surgery
- Superior cosmetic results with minimal scarring 3, 1, 6
- Reduced postoperative pain 3, 6
- Shorter hospital stay 3
- No increase in complications or hospital stay compared to conventional thyroidectomy 5
Conversion to Open Surgery
Conversion is required when:
- Frozen section demonstrates differentiated thyroid carcinoma requiring selective lymphadenectomy 3
- Large thyroid volume encountered intraoperatively 3
- Massive hemorrhage from upper pole vessels 3
When conversion is needed, extend the incision to 4 cm to achieve adequate exposure for lymphadenectomy or hemostasis 3.
Critical Caveats
When NOT to Use Minimally Invasive Approach
- Retrosternal goiters require complete preoperative cross-sectional imaging (CT preferred over MRI) to assess tracheal compression and mediastinal extension 7
- Invasive thyroid cancer with worrisome clinical findings (firm nodules, fixation, rapid growth, enlarged lymph nodes) should not be approached minimally invasively regardless of FNA results 2
- Total thyroidectomy with central neck dissection is mandatory for medullary thyroid cancer, which may not be suitable for minimally invasive approaches 2
Postoperative Management
- Initiate levothyroxine therapy immediately post-surgery for both hormone replacement and TSH suppression 2
- Monitor TSH levels: maintain 0.5-2 mIU/L for low-risk patients with excellent response; 0.1-0.5 mIU/L for intermediate-to-high risk patients 4
- Neck ultrasound is the most effective tool for detecting structural disease during follow-up 4
Evidence Quality
The recommendation for MIVAT is based on high-quality 2019 ESMO guidelines 4 supporting lobectomy for low-risk disease, combined with consistent research evidence from multiple studies showing safety and feasibility 3, 1, 5, 6. A 2021 meta-analysis of 98 studies confirmed non-inferiority to conventional thyroidectomy 5.