[K] If surgery is chosen, how should it be accomplished?
[K1] Preparation of patients with TMNG or TA for surgery
- RECOMMENDATION 39
If surgery is chosen as treatment for TMNG or TA, patients with overt hyperthyroidism should be rendered euthyroid prior to the procedure with methimazole pretreatment (in the absence of allergy to the medication), with or without beta-adrenergic blockade. Preoperative iodine should not be used in this setting. 1/+00
Risks of surgery are increased in the presence of thyrotoxicosis. Thyrotoxic crisis during or after the operation can result in extreme hypermetabolism, hyperthermia, tachycardia, hypertension, coma, or death. Therefore, prevention with careful preparation of the patient is of paramount importance (170,171). The literature reports a very low risk of anesthesia-related mortality associated with thyroidectomy (151,172). In patients who wish to avoid general anesthesia, or who have significant comorbidities, this risk can be lowered further when cervical block anesthesia with sedation is employed by thyroid surgeons and anesthesiologists experienced in this approach (173). However, this technique is not widely available in the U.S. Preoperative iodine therapy is not indicated due to risk of exacerbating the hyperthyroidism (174).
[K2] The surgical procedure and choice of surgeon
- RECOMMENDATION 40
If surgery is chosen as treatment for TMNG, near- total or total thyroidectomy should be performed. 1/++0
Recurrence can be avoided in TMNG if a near-total or total thyroidectomy is performed initially. This procedure can be performed with the same low rate of complications as a subtotal thyroidectomy (175–178). Reoperation for recurrent or persistant goiter results in a 3- to 10-fold increase in risk for permanent vocal cord paralysis or hypoparathyroidism (179,180).
Surgery for TMNG should be performed by a high-volume thyroid surgeon. 1/++0
Data regarding outcomes following thyroidectomy in elderly patients have shown conflicting results. Overall, however, studies conducted at the population level have demonstrated significantly higher rates of postoperative complications, longer length of hospital stay, and higher costs among elderly patients (122). Data showing equivalent outcomes among the elderly usually have come from high-volume centers (181). There are robust data demonstrating that surgeon volume of thyroidectomies is an independent predictor of patient clinical and economic outcomes (i.e., in-hospital complications, length of stay, and total hospital charges) following thyroid surgery (122,123,182). There is a robust, statistically significant association between increasing surgeon volume and superior patient outcomes for thyroidectomy. Data show that surgeons who perform more than 30 thyroid surgeries per year have superior patient clinical and economic outcomes compared to those who perform fewer, and surgeons who perform at least 100 per year have still better outcomes. It is for this reason that near-total or total thyroidectomy for TMNG is best performed by a high-volume thyroid surgeon (123,181,182).
- RECOMMENDATION 42
If surgery is chosen as the treatment for TA, an ipsilateral thyroid lobectomy, or isthmusectomy if the adenoma is in the thyroid isthmus, should be performed. 1/++0
A preoperative thyroid ultrasound is useful, as it will detect the presence of contralateral nodularity that is suspicious in appearance or that will necessitate future surveillance, both circumstances in which a total thyroidectomy may be more appropriate. Lobectomy removes the TA while leaving normal thyroid tissue, allowing residual normal thyroid function in the majority of patients. One large clinical series for TA demonstrated no surgical deaths and low complication rates (151). Patients with positive antithyroid antibodies preoperatively have a higher risk of postoperative hypothyroidism (166).
- RECOMMENDATION 43
We suggest that surgery for TA be performed by a high-volume surgeon. 2/++0
While surgeon experience in the setting of TA is of somewhat less importance than in TMNG, it remains a factor to consider in deciding between surgery and radioactive iodine. High-volume thyroid surgeons tend to have better outcomes following lobectomy than low-volume surgeons, but the differences are not statistically significant (122).
[K3] Postoperative care
- RECOMMENDATION 44
Following thyroidectomy for TMNG, we suggest that serum calcium or intact parathyroid hormone levels be measured, and that oral calcium and calcitriol supplementation be administered based on these results. 2/+00
Technical remarks: The management of hypocalcemia following thyroidectomy for TMNG is essentially the same as that described in section F3 for postoperative management in GD. Severe or prolonged preoperative hyperthyroidism, and larger size and greater vascularity of the goiter (more typically seen in GD) increases the risks of postoperative hypocalcemia.
- RECOMMENDATION 45
Methimazole should be stopped at the time of surgery for TMNG or TA. Beta-adrenergic blockade should be slowly discontinued following surgery. 1/+00
- RECOMMENDATION 46
Following surgery for TMNG, thyroid hormone replacement should be started at a dose appropriate for the patient's weight (0.8 mcg/lb or 1.7 mcg/kg) and age, with elderly patients needing somewhat less. TSH should be measured every 1–2 months until stable, and then annually. 1/+00
Technical remarks: If a significant thyroid remnant remains following thyroidectomy, because such a remnant may demonstrate autonomous production of thyroid hormone, immediate postoperative doses of thyroid hormone should be initiated at somewhat less than full replacement doses and subsequently adjusted based on thyroid function testing.
- RECOMMENDATION 47
Following surgery for TA, TSH and estimated free T4 levels should be obtained 4–6 weeks after surgery, and thyroid hormone supplementation started if there is a persistent rise in TSH above the normal range. 1/+00
[K4] Treatment of persistent or recurrent disease following surgery for TMNG or TA
- RECOMMENDATION 48
Radioactive iodine therapy should be used for retreatment of persistent or recurrent hyperthyroidism following inadequate surgery for TMNG or TA. 1/+00
Persistent or recurrent hyperthyroidism following surgery is indicative of inadequate surgery. As remedial thyroid surgery comes at significantly increased risk of hypoparathyroidism and RLN injury, it should be avoided if possible in favor of radioactive iodine therapy (179,180). If this is not an option, it is essential that the surgery be performed by a high-volume thyroid surgeon.