Perioperative management - Total thyroidectomy in bilateral nodular goiter

Bilateral multinodular goiter

• The long-term recurrence rate of subtotal thyroid resection in benign nodular goiter reportedly is as high as 40%.
• Repeat surgery following initial subtotal resection suffers from a markedly higher morbidity (vocal cord paralysis, hypocalcemia).
• However, given sufficient experience the rate of intraoperative and postoperative complications in total thyroidectomy is comparable to that of subtotal resection.

Other indications for total thyroidectomy:

• Follicular and medullary cancer
• Papillary cancer with diameter > 1cm or multifocal spread
• Undifferentiated malignancies without invasion of adjacent structures
• Stenosis of the trachea and/or esophagus with dyspnea/dysphagia
• Thyroid dysfunction uncontrolled by medication (Graves disease, severe iodine induced hyperthyroidism)
• Hashimoto’s (chronic lymphocytic) thyroiditis with suspected cancer
• Rare: Subacute granulomatous thyroiditis (de Quervain)

• Indifferent nodules on ultrasound/scintiscan imaging
• Cardiopulmonary risk assessment

3.1 Basic diagnostic work-up

Medical history

• Local symptoms of thyroid enlargement (pressure/globus sensation in the neck; dysphagia and dyspnea, particularly on exertion)
• Symptoms of hyperthyroidism
• Medication (iodine-containing drugs, antithyroids)
• Family history of thyroid disorders
• Preexisting cervical spine problems (cervical reclination during head positioning!)

Physical examination

• Palpation (size: lobe texture; nodules; elevation of lobes on swallowing; palpable lymph nodes)
• Measurement of cervical circumference
• Endocrine ophthalmopathy

Stages of thyroid enlargement

Ia Palpable goiter, not visible even with the head reclined

Ib Goiter, only visible with the head reclined

II Goiter, visible with the head in normal position

III Goiter with signs of local congestion and compression

Ultrasonography

Basic modality for assessing thyroid morphology:

• Volume measurement by cross sectional and longitudinal ultrasonography
• Distribution, echo texture and delineation of nodules
• Blood flow and blood supply
• Relationship with adjacent structures
• Assessment of lymph node status
• Possible retrosternal growth

Thyroid uptake scintiscan

Basic modality for imagingassessment thyroid function:

• Indicative of areas with decreased (cold nodule) or increased (warm nodule) activity
• Cold nodules do not demonstrate any uptake or only very little, while warm nodules store more tracer than the surrounding tissue; hot nodules show intensive uptake with concurrent suppression in the surrounding tissue
• Autonomous areas are no longer controlled by TSH and may only be unmasked by suppression scintigraphy
• Cold nodules anechoic on ultrasound and demonstrated on uptake scintiscanning represent cysts.
• Cold nodules not anechoic on ultrasound suggest suspected cancer and should be evaluated (see optional preoperative diagnostics)

Lab studies

• Usual preoperative panel (including RBC; coagulation, calcium), possibly additional parameters depending on underlying disorder
• TSH, thyroid hormones
• The most important in vitroparameter is TSH whose pathology is indicative of persistent thyroid dysfunction Low TSH levels raise the suspicion of hyperthyroidism, while elevated levels suggest hypothyroidism. In these cases, thyroid hormone (fT3 and fT4) studies are mandatory; in theory this could be foregone if both TSH and the clinical situation are normal 

Functional examination of vocal cords

Preoperative laryngoscopy by ENT consultation evaluating vocal cord mobility is mandatory to detect, before surgery, any preexisting dysfunction of the recurrent nerve, e.g., after previous operations or in case of malignancy

• Allows situational surgical technique
• Is the foundation of all perioperative quality assurance
• Note: Preoperative and postoperative laryngoscopy, together with intraoperative neuromonitoring, constitute an inseparable diagnostic unit. Without knowledge of the clinical function of the larynx neuromonitoring does not yield any usable insight!

3.2. Optional diagnostic work-up

Magnetic resonance imaging/Computerized tomography without contrast

• In suspected retrosternal goiter to evaluate the extent of the retrosternal part, since this will facilitate preoperative planning of possible surgical access to the chest (sternotomy)
• In marked local compression symptoms
• In growths invading adjacent structures

The drawback in CT studies is that they categorically must be performed without contrast agents; otherwise there would be the risk of iodine induced hyperthyroidism and iodine contamination in the context of radioactive iodine treatment. Since external administration of iodine will block the iodine receptors for an extended period, this would prevent radioactive iodine treatment and thyroid uptake scintiscanning

Film of trachea(not required in case of CT/MRI)

• In suspected tracheomalacia

Lab studies

• Thyreoglobulin
• For follow-up monitoring in differentiated thyroid cancer; should not be detectable in serum after total thyroid resection; any later elevation suggests recurrence or metastasis
• Elevated calcitonin levels suggest medullary thyroid cancer

Thyroid antibodies in the diagnostic work-up of autoimmune thyroid disease and thyroiditis

• Antibodies against TSH receptors (TSHR Ab) should be determined if the clinical picture and imaging cannot differentiate clearly between Graves disease and non-autoimmune hyperthyroidism.
• Antibodies against thyroid peroxidase (TPO-Ab) are determined in suspected autoimmune thyroid disease; their levels are elevated in 90% of patients with autoimmune thyroiditis Hashimoto and in 70% of cases with Graves disease.
• Antibodies against thyroglobulin (TgAb) are determined in suspected autoimmune thyroiditis.

Fine-needle aspiration biopsy/cytology

• Suspected malignancy with solitary hypoechoic cold or rapidly growing nodule ≧ 1cm in diameter (nodules less than 1cm should be followed up every six months by ultrasonography)
• Diffusely delineated nodules
• Solitary nodules in status post percutaneous high-voltage radiotherapy of the neck
• Suspected subacute or chronic lymphocytic thyroiditis
• Sensitivity and specificity for cytology is about 80%–90%
• Therapeutic fine-needle centesis: In large thyroid cysts with signs of local displacement; in acute purulent thyroiditis

This link shows an algorithm for the diagnostic work-up of goiters: Diagnostic work-up of goiters 

Euthyroidism

• No special preparation required

Hypothyroidism

• This link provides you with information on the preoperative pretreatment of hypothyroidism: Preoperative hypothyroidism 

Hyperthyroidism

All patients with hyperthyroidism undergoing elective thyroid surgery must present with a stable euthyroid metabolism before the operation.

• Administration of an antithyroid drug over a period of several weeks is the safest way.
• In case of adverse events under antithyroid medication necessitating termination of the drug this leaves the option of “Plummering” with Lugol’s iodine solution
• Administration of beta blockers for several days may be adequate in minor hyperthyroidism.

This link provides you with information on the preoperative pretreatment of hyperthyroidism: Preoperative hyperthyroidism 

Increased cardiopulmonary risk

• Further elucidation of the surgical risk with additional diagnostic work-up (exercise ECG; echocardiography; coronary angiography; pulmonary function tests)

Anticoagulants

• Should be withdrawn 7 days before surgery, bridging possibly required

• Hemorrhage/secondary bleeding/hematoma
• Wound infection/delayed wound healing
• Vocal cord paralysis (in experienced centers < 1%)
• Permanent hypoparathyroidism (in experienced centers < 1%)
• Thromboembolism
• Position induced cervical complaints
• Necessity of postoperative hormone replacement treatment

In very large goiters and before repeat surgery the patient should also be informed of rare complications:

• Injury to the sympathetic nerve (Horner syndrome)
• Injury to trachea and cervical vessels