GUIDELINES FOR SURGERY 
III. Surgical treatment of goiter with thyroid dysfunction
 
 
 
III-1. HYPERTHYROIDISM: GRAVES'S DISEASE AND TOXIC NODULAR GOITER
 
 
At present, the indications for surgical treatment for patients with Graves-Basedow’s disease differ significantly from country to country. In the United States and in the majority of European countries, surgical therapy for Graves-Basedow’s disease is not considered  primary treatment, but is selected when other treatments fail or are contraindicated because of an allergic reaction to antithyroid drugs or unusually low iodine uptakes by the thyroid. For toxic adenoma and toxic multinodular goiter, thyroidectomy remains the treatment of choice in most countries. In Japan, unlike Western countries, many patients with Graves-Basedow’s disease are treated surgically because of the excellent long-term results and few complications (Harada 1997). The distinct advantages of surgery over other treatment methods are as follows: (1) it can be carried out with the highest rate  of remission, and  (2) euthyroidism can be achieved in the shortest duration as concerns the three possible modalities of treatment. Unfortunately, with the passage of time, the number of surgeons skilled in treating Graves- Basedow’s disease has decreased, because of a lack of surgical experience. These problems can be reduced by referring patients to centers specializing in endocrine surgery. According to a survey carried out by the European Thyroid Association, surgery is only infrequently used as a primary treatment for patients with Graves-Basedow’s disease. Thus, overall only 7.3% of patients were selected for surgical treatment and the primary indication was a large goiter. Even in cases of recurrent hyperthyroidism after antithyroid drug treatment, the rate of thyroidectomy did not exceed 10% (Glinoer 1987). Worldwide, the number of patients with Graves-Basedow’s disease who are treated surgically is decreasing. In 1972, Hamburger noted that “surgery is indicated only  (a) when antithyroid drugs fail; (b) when antithyroid drugs are likely to fail; (c) when medical management is feared by patient or doctor; and (d) when surgery is the safest treatment.” (Hamburger  1972). Today, therefore in the majority of Western countries, surgery is primarily indicated for patients with a recurrence of hyperthyroidism after the withdrawal of properly managed medical treatment and the suspicion or documentation of  coexistent Graves-Basedow’s disease with a malignant neoplasm, or for those in whom other forms of treatment are unacceptable (Hamburger 1972, McFarland 1988, Menegaux 1993).

In patients with a solitary toxic adenoma or a multinodular toxic goiter, thyroidectomy is generally considered the first choice of treatment worldwide, except  when the patient is at risk. Antithyroid drugs and radioiodine are not very efficient in these patients and are not always successful (Eyre- Brook 1988, Heimann 1978).

It is imperative to render the patient euthyroid before thyroidectomy by administering antithyroid drugs with or without propranolol. Lugol’s solution is recommended for a period of  5 or 6 days preoperatively to decrease the vascularity of the thyroid gland and hence the possibility of intraoperative bleeding.
The technique for subtotal thyroidectomy (resection of the bilateral thyroid lobes with the isthmus, leaving a small amount of the posterior rim of each lobe) was developed after much trial and error but, is now established as a standard procedure.

Total  excision of one thyroid lobe and subtotal resection of the other side has also been recommended (Andaker 1992, Menegaux 1993).The risk of complications with this procedure is similar to that in subtotal thyroidectomy. However, there has been a slight decrease in the incidence of recurrent hyperthyroidism and a higher incidence of hypothyroidism (Andaker 1992).

The factors that predispose a patient to recurrent hyperthyroidism or the development of hypothyroidism have not been clearly elucidated. Many factors may have some influence on postoperative hypothyroidism and recurrent hyperthyroidism, but the remnant size is the most important factor determining the postoperative thyroid function (Cusick 1987, Toft 1987, Okamoto 1992). An increased incidence of hypothyroidism may be anticipated with a small remnant, and an increased incidence of recurrent hyperthyroidism with a larger remnant. Controversy exists regarding the optimal size of the remnant to be left after subtotal thyroidectomy. In patients with Graves-Basedow’s disease, the optimal remnant weight reported by many authors has differed significantly, ranging from 2 to 30 g (Hedley 1972, Michie 1972, Gough 1974, Farnell 1981, Bradley 1983). A euthyroid rate of 94% has been obtained with modified subtotal thyroidectomy leaving an accurately measured 5 g thyroid remnant and an intact inferior thyroid artery on each side (Bradley 1980). One suggestion is to base the remnant size on the severity of the hyperthyroidism: 1.0 g in severe cases, 2.0-3.0 g in moderate cases, and 6.0 to 10 g in mild cases (Kuma 1958). Currently, there is  general agreement on leaving a remnant weighing from 4 to 8 g (Harada 1984) and few surgeons recommend leaving a remnant larger than 10 g (Cusick 1987). An exact estimation of  the remnant weight is difficult (Tweedle 1977). In our practice the weight of the remnant  is compared with that of a part of the resected  thyroid lobe, which part is weighed. These remnants ranged from 4 to 6 g.
See  and 

Thyroid remnants smaller than 5 g result in an increased incidence of postoperative hypothyroidism; a remnant smaller than 5 g should, in most patients, be avoided (Tweedle 1977, Michie 1978).
Many other factors have also been proposed to explain the development of postoperative hyperthyroidism and hypothyroidism. A comparative study of th outcome of surgical treatment for Graves-Basedow’s disease revealed that the prevalence of postoperative hypothyroidism was 5 times lower, but recurrent hyperthyroidism was 5 times higher in an area with a high iodine level than in one with a low iodine level (Thjodleifsson 1977). The extent of lymphocytic infiltration in the thyroid tissue has also been proposed to be associated with an increased frequency of postoperative hypothyroidism (Harada 1984). The level of antimicrosomal antibody rates may also influence Graves-Basedow’s disease. Some studies suggest that a higher antimicrosomal antibody level predicts an increased risk of postoperative hypothyroidism (Kuma 1958, Michie 1978). It was hoped  that TBII assays would be predictable indicators of the postoperative thyroid function. Unfortunately, surgery does not affect the TBII levels in all cases, and there is no good correlation between the postoperative TBII levels and postoperative thyroid function (Harada 1987, Kuma 1991).

Today, surgical deaths and postoperative thyrotoxic crises are virtually unknown, because patients are well controlled preoperatively and the patients at highest risk are not subjected to thyroidectomy.

Postoperative determination of the serum calcium level and examination of the vocal cords by indirect or direct laryngoscopy are indicated. In experienced surgical hands, permanent laryngeal nerve palsy and hypocalcemia develop in less than 1% of the patients (Harada 1987, Sugino 1993). Transient palsy of the recurrent nerve as a result of a retraction of the nerve or some other cause is uncommon and the nerve usually recovers within several months. Transient hypocalcemia is thought to be due to damage or ischemia of the parathyroid glands. We have audited  the postoperative complications  in a group of  252  patients  with toxic nodular goiter (171 pts) or with Graves-Basedow’s disease (81 pts) who were operated on in our unit in a 4- year period

 
Table 3.
Complications of  subtotal thyroidectomy in 252 patients with Graves-Basedow’s disease and toxic nodular goiter
 
 
 
Toxic nodular goiter
n=171
Graves-Basedow’s disease
n=81
Laryngeal nerve palsy
Transient
2.3%
2.8%
Permanent
0.5%
1.2%
Hypocalcemia
Transient
5.2%
6.1%
Permanent
1.1%
1.2%
Hemorrhage
3.5%
3.7%
 
There is considerable variation in the reported incidence of postoperative hypothyroidism and recurrent hyperthyroidism after thyroidectomy in patients with Graves-Basedow’s disease. Some series in the literature include patients with toxic diffuse goiters, toxic multinodular goiters or toxic adenomas (Toft 1978, Sugrue 1983). In such series, the incidence of hypothyroidism might be lower because postoperative hypothyroidism occurs less commonly in patients with toxic nodular goiters (Simms 1983). The reported incidence of postoperative permanent hypothyroidism ranges from 10 to 50% (Michie 1972, Gough 1974, Blichert-Toft 1977). Kuma et al characterized the type of postoperative hypothyroidism in patients with Graves-Basedow’s disease who underwent subtotal thyroidectomy (Kuma 1991). Interestingly, nearly 40 to 50% of the patients experienced subclinical hypothyroidism during the first 4 years after surgery, and most of them experienced euthyroidism later without any treatment (Kuma 1991).
Postoperative thyroid functions in a group of  201 patients with a 2-year follow-up period  after operation  in our unit are recorded in Table 4.
 
Table 4.
Postoperative thyroid function test results (2- year follow-up -  subtotal thyroidectomy)
n=201
 
 
Toxic nodular goiter
Graves-Basedow’s disease
Euthyroid
88.1%
71.3%
Latent hypothyroid
10.4%
25.7%
Recurrent hyperthyroidism
1.5%
3%
                                                                     

Our results regarding the surgical complications (Table 3.) and the postoperative thyroid function (Table 4) are comparable with those reported from other centers (Farnell 1981,  Sugrue 1983,  Kuma 1991, Harada 1997), and justify the recommendation of our surgical policy.

References:

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