Overview
Definition:
Reoperative thyroidectomy refers to any surgical removal of thyroid tissue performed after an initial thyroidectomy
It is indicated for persistent, recurrent, or new thyroid pathology that necessitates further surgical intervention.
Epidemiology:
The incidence of reoperative thyroidectomy varies, with rates typically ranging from 1% to 15% of all thyroidectomies
Factors influencing this include the initial diagnosis (e.g., malignancy, inadequate resection), the development of new nodules, or complications like thyroid storm in inadequately treated hyperthyroidism.
Clinical Significance:
Reoperative thyroidectomy presents unique challenges due to altered anatomy, fibrosis, and potential scarring from the previous surgery
Careful planning and execution are crucial to minimize morbidity, particularly regarding recurrent laryngeal nerve (RLN) injury and hypoparathyroidism, which are significantly higher compared to primary thyroidectomy.
Indications
Persistent Or Recurrent Thyroid Cancer:
Failure to achieve complete tumor removal during the initial surgery, or the development of new metastatic disease in the thyroid bed or lymph nodes
This is a common indication for reoperation, especially for differentiated thyroid cancers.
Symptomatic Recurrent Goiter:
Significant enlargement of remaining thyroid tissue causing compressive symptoms (dysphagia, dyspnea, hoarseness) or cosmetic concerns
This is more frequent in multinodular goiters where not all nodules were removed.
Suspicion Of Malignancy In Remaining Thyroid Tissue:
Development of new suspicious nodules on imaging or palpable masses in the remnant thyroid tissue or cervical lymph nodes following initial surgery for benign or indeterminate lesions.
Persistent Hyperthyroidism:
Inadequate resection of thyroid tissue leading to continued hyperthyroid symptoms, particularly if medical management is not tolerated or effective
This is less common with modern surgical techniques.
Complications Requiring Reoperation:
Rarely, complications from the initial surgery like persistent thyroglossal duct remnant or branchial cleft anomalies may necessitate reoperation.
Preoperative Preparation
Detailed History And Physical Examination:
Thorough review of previous surgical records, pathology reports, and anesthetic notes
A meticulous head and neck examination is performed, paying close attention to vocal cord function and any signs of tracheal or esophageal compression.
Imaging Studies:
Ultrasound is essential to localize residual thyroid tissue, assess nodule characteristics, and evaluate lymph node status
CT or MRI may be used for complex cases or suspected extrathyroidal extension
Radioactive iodine (RAI) scans can be useful for identifying functioning thyroid tissue in cases of recurrent thyroid cancer.
Vocal Cord Assessment:
Flexible laryngoscopy or videostroboscopy by an otolaryngologist is highly recommended to assess baseline vocal cord function and identify any existing paresis or paralysis, which can be exacerbated during reoperation.
Thyroid Function Tests:
TSH, free T4, and free T3 levels are measured to assess thyroid status
For suspected recurrent cancer, thyroglobulin (Tg) levels with or without antibodies may be obtained.
Informed Consent:
Comprehensive discussion with the patient regarding the increased risks of reoperative thyroidectomy, including RLN injury (temporary or permanent), hypoparathyroidism (temporary or permanent), bleeding, infection, and the possibility of needing further intervention.
Surgical Technique And Strategies
Approach:
The surgical approach is typically a transverse cervical incision, often placed slightly above or along the scar of the previous incision to facilitate dissection and minimize cosmetic deformity
Careful dissection is paramount to avoid injury to vital structures.
Identification And Preservation Of Structures:
Extreme care is taken to identify and preserve the recurrent laryngeal nerves (RLNs) and parathyroid glands
Intraoperative nerve monitoring (IONM) is strongly recommended to aid in RLN identification and functional assessment
Parathyroid glands should be identified, preserved in situ, or if detached, autotransplanted to the sternocleidomastoid muscle.
Dissection Planes:
Dissection should ideally remain in relatively avascular planes, often along the pretracheal fascia, to minimize bleeding and tissue damage
Adhesions and scar tissue can make dissection difficult, requiring meticulous subperiosteal dissection from the trachea and larynx when necessary.
Extent Of Resection:
The extent of resection depends on the indication
For benign recurrent goiter, subtotal or near-total thyroidectomy of the remnant is performed
For well-differentiated thyroid cancer, completion thyroidectomy and central compartment lymph node dissection (level VI) are standard
Lateral neck dissection (levels II-V) is performed if there is evidence of lateral lymph node metastasis.
Hemorrhasis Control:
Meticulous hemostasis is crucial
Ligasure or harmonic scalpel may be useful for controlling small vessels and minimizing dissection trauma
Careful ligation of larger vessels is performed.
Complications
Recurrent Laryngeal Nerve Injury:
The risk is significantly higher in reoperative thyroidectomy (5-10% for temporary, 1-5% for permanent RLN palsy) compared to primary surgery
This can lead to hoarseness, vocal fatigue, and aspiration
Careful identification, IONM, and meticulous dissection are key to prevention.
Hypoparathyroidism:
Damage or devascularization of parathyroid glands can lead to hypocalcemia
The risk is increased in reoperation (5-20% for temporary, 1-5% for permanent)
Monitoring calcium and PTH levels postoperatively is essential
Temporary hypoparathyroidism may require calcium and vitamin D supplementation.
Hematoma And Seroma:
Bleeding or fluid collection in the surgical site can occur, potentially compromising the airway
Early detection and management (e.g., drainage) are important
A drain is often placed in reoperative thyroidectomies.
Infection:
While less common, surgical site infection can occur
Prophylactic antibiotics are typically administered perioperatively.
Dysphagia:
Temporary or persistent difficulty swallowing can result from esophageal manipulation, inflammation, or RLN injury.
Key Points
Exam Focus:
Reoperative thyroidectomy carries increased risks of RLN injury and hypoparathyroidism
Intraoperative nerve monitoring (IONM) and meticulous dissection are critical
Always review prior pathology and operative reports.
Clinical Pearls:
When in doubt, leave a small amount of thyroid tissue if the indication is benign to minimize risk
For malignancy, aim for complete resection but prioritize nerve and parathyroid preservation
IONM significantly improves RLN identification and safety.
Common Mistakes:
Inadequate preoperative assessment of vocal cord function
Blind dissection without identifying crucial structures like RLNs and parathyroid glands
Assuming anatomy is the same as primary thyroidectomy
Failure to use IONM when indicated
Over-reliance on cautery without definitive ligation.