Hypothyroidism following partial thyroidectomy for thyrotoxicosis and its relationship to thyroid remnant size

Results of surgical treatment in multinodular goiter with an intrathoracic component

PURPOSE

(1) To determine the clinical profile of intrathoracic multinodular goiter (IMG); (2) to evaluate the results of surgery, and (3) to analyze the incidence of malignancy and its evolution.

METHODS

Two hundred and forty-seven operated cases of IMG were reviewed. These cases of IMG had all been diagnosed according to Eschapse's definition (>3cm below the sternal manubrium). The morbidity and postoperative evolution were analyzed. A comparative study was carried out on a group of 425 cases of nonintrathoracic goiter. We applied the chi(2) test, Student's t-test, and a logistical regression analysis.

RESULTS

Intrathoracic MG occurs in patients over 60 years of age, with goiter which has a long evolution time (>12 years), and more than 60% are symptomatic. Oral tracheal intubation was difficult in 10% (n = 24) of the cases, and 7 required the use of a fibrobronchoscope. In 8 cases (3%) a thoracic approach was necessary. Morbidity occurred in 24% (n = 59), most notably 29 recurring lesions (12%), of which 2 were definitive (0.8%), and 31 hypoparathyroidisms (13%), of which 1 was definitive (0.4%). No significant difference was found in the postsurgical morbidity between the intrathoracic MG and the nonintrathoracic cases. Regarding the remission of the symptoms, the results were excellent. In 14 cases (5.7%) thyroid carcinoma was related with, most of these being papillary microcarcinoma. In 10 of the 49 cases of partial surgery (20%) a relapse of the goiter was observed.

CONCLUSIONS

Intrathoracic MG is usually asymptomatic and it occurs in goiter with a long time of evolution. Surgery is a good therapeutic option given that the goiter can be removed via the neck, with low morbidity, a remission of the symptoms, malignancy is ruled out, and recurrence can be avoided if a total thyroidectomy is performed.

Subtotal Thyroidectomy: A Reliable Method to Achieve Euthyroidism in Graves’ Disease. Prognostic Factors

BACKGROUND

Subtotal thyroidectomy is a widely accepted surgical procedure for Graves' disease. The purpose of this work is to evaluate functional long-term results and determine predictive prognostic factors of postoperative thyroid function.

STUDY DESIGN

This is a retrospective study conducted on 202 patients with Graves' disease undergoing subtotal thyroidectomy during the period 1979-2002. Predictive prognostic factors of final thyroid status were investigated by logistic ordinal regression, and probability of hypothyroidism during the years of follow-up was obtained by the Kaplan-Meier method.

RESULTS

Surgery controlled hyperthyroidism in 196 out of 202 patients (97%). The probability of hypo-, eu-, and hyperthyroidism at 5 years was 62.1%, 35.5%, and 2.4%, respectively. No statistical change in thyroid function occurred in the follow-up after 60 months. Multivariate analysis by a logistic ordinal regression analysis showed that weight of the remnant, age, and gender seemed to influence long-term thyroid function. The higher rates of euthyroidism were obtained when the remnant weight was between 6 and 8 g. No recurrence or persistence of hyperthyroidism occurred with remnant weights under 5 g.

CONCLUSIONS

Subtotal thyroidectomy controlled hyperfunction symptoms in 97% of our patients. Cure (euthyroidism) of Graves' disease patients should be attempted by leaving a thyroid tissue remnant between 6 and 8 g. Even more significant, our results suggest that euthyroidism rates could be improved by leaving a smaller remnant in elderly women and greater remnants in young men.

Results of surgery for toxic multinodular goiter

PURPOSE

We analyzed the clinical and histological features of patients operated on for toxic multinodular goiter (TMG) to determine the clinical profile and evaluate the surgical results.

METHODS

We reviewed 672 patients who underwent surgery for multinodular goiter (MG), 112 (17%) of whom had hyperthyroidism, and analyzed the epidemiological, clinical, and surgical variables.

RESULTS

The patients with TMG tended to be older than those with nontoxic MG, with a greater evolution time of the goiter and a higher rate of positive antithyroid antibodies. In the multivariate analysis, the only feature characteristic of TMG, as opposed to nontoxic MG, was the evolution time. Morbidity was 34%, representative of the fact that that most of the patients were seen before the establishment of our endocrine surgical unit. The hyperthyroid symptoms resolved in all patients, but 4 of 17 patients who underwent partial surgical resection showed signs of relapse within a follow-up period of 98 +/- 71 months.

CONCLUSIONS

TMG is characterized by a long evolution time and is most effectively treated by total thyroidectomy, which achieves complete remission from symptoms, without relapse, and is necessary if there is associated carcinoma. However, the incidence of complications may be high if this procedure is not carried out by surgeons with experience in endocrine surgery.

[Prognostic factors of thyroid function following surgical therapy in Graves-Basedow's disease]

BACKGROUND

The goals of this work are to describe late thyroid function and to determine predictive factors of permanent hypothyroidism following surgery in Graves-Basedow's disease.

PATIENTS AND METHOD

From 1979 to 1999, 107 patients with hyperthyroidism due to Graves-Basedow's disease underwent subtotal thyroidectomy. We performed life-table analysis and calculated the cumulative incidence of hypothyroidism by means of the Kaplan-Meier's method. Survival (euthyroidism)within patients groups was compared using the Mantel-Cox method. Variables influencing long-term thyroid function were determined by estimating the Odds ratio with a logistic regression model.

RESULTS

The probability of euthyroidism among all 107 patients at 240 months was 51.4%.Age, gender, duration of both hyperthyroidism and antithyroid therapy and weight of resected thyroid tissue did not influence the eventual outcome. The weight of thyroid remnant was 5.4 (1.5)g and the conditional logistic regression analysis showed that weight of thyroid remnant was the only variable influencing long-term thyroid function. Hyperthyroidism relapsed in 5 patients.

CONCLUSIONS

In our experience,surgery represents a definitive alternative treatment with a risk of hypothyroidism within the first 2 years of 43.9%. The weight of thyroid remnant is the only variable influencing long-term thyroid function.

Surgical treatment of Graves' disease

Seven men and 81 women were operated on for Graves' disease. Their median age was 33 years. Eleven patients underwent a bilateral subtotal lobectomy; 77 patients underwent a complete lobectomy with contralateral partial lobectomy. Forty-seven patients were treated before 1981. In these patients, the weight of the thyroid remnant was estimated empirically between 5 and 12 g. In the 41 patients treated since 1981, the remnant weight was estimated at 5 g by comparative weighing. There were no postoperative deaths. Functional results were established in 83 patients with an average follow-up of 50 months (range 12 to 156 months), with control of vocal cord mobility demonstrated by indirect laryngoscopy in 66 patients. Hormonal determinations were carried out in 74 patients. There were no cases of permanent hypoparathyroidism. Three patients (4.5 percent) had unilateral vocal cord dysfunction. Twelve patients (14.5 percent) had clinical and biologic hypothyroidism, which occurred within 1 year postoperatively in 11 cases. Seven patients (8.3 percent) had latent hypothyroidism only discovered by hormonal determinations. Fifteen patients (17.8 percent) had recurrent hyperthyroidism, 6 of whom were diagnosed by hormonal determinations. The actuarial recurrence rate increased progressively up to the sixth postoperative year. The only predictive factor for recurrence was the type of operation. Patients who underwent a bilateral subtotal lobectomy had more recurrences than patients who underwent a complete lobectomy with partial contralateral lobectomy (p less than 0.01). These results suggest that patients should be followed closely for many years and should undergo hormonal determinations regularly, as some recurrences can occur 5 years or more after operation with very few symptoms.

Long term thyroid function after subtotal thyroidectomy for Graves' disease

Between 1973 and 1980, 93 patients with Graves' disease underwent subtotal thyroidectomy by the same surgeon (the size of thyroid remnant was 4 g per side). No case of operative mortality, no case of thyroid storm nor of surgical complications occurred. Three months after surgery 40% of patients were euthyroid, 25% had overt hypothyroidism, 35% had subclinical hypothyroidism. In the following yr important variations of thyroid function were observed. The number of patients with subclinical hypothyroidism decreased slowly (22% and 9% at 3 and 6 yr, respectively), and some became euthyroid, some hypothyroid, others relapsed. Seven patients had recurrent hyperthyroidism. In particular at 3 yr 45% of patients were euthyroid, 28% had overt hypothyroidism, 22% had subclinical hypothyroidism, 4% had recurrence; at 6 yr 56% were euthyroid, 32% had overt hypothyroidism, 9% had subclinical hypothyroidism, 3% had recurrence. Four out of the 8 patients operated under 20-yr-old became hypothyroid in comparison with only 2 out of the 15 patients over 50-yr-old. Relapses were present only in patients operated at less than 40-yr and only in females. No correlation was found between thyroid lymphocytic infiltration and thyroid function after surgery, nor between the presence of antithyroid antibodies and hypothyroidism. All cases who relapsed had high TMA titers both before and after operation. This study confirms the need for accurate follow-up after subtotal thyroidectomy for Graves' disease.

Hyperthyroidism and hypothyroidism complicating the treatment of thyrotoxicosis

Three separate studies of recurrent hyperthyroidism and hypothyroidism in groups of patients treated for thyrotoxicosis by anti-thyroid drugs, surgery and radioiodine are presented. The incidence is compared in the three groups. Two hundred and fifty-three patients with primary thyrotoxicosis received a year-long course of anti-thyroid drugs: 43 per cent relapsed in the first year following the completion of treatment. Of those remaining euthyroid at the beginning of the second year after treatment a further 21 per cent relapsed during that year and in subsequent years, 21 per cent, 18 per cent and 13 per cent of those remaining euthyroid at the start of the third, fourth and fifth years relapsed. Of those followed for the full 5 years 26 per cent remained in remission and 74 per cent had relapsed over this period. After bilateral subtotal thyroidectomy for thyrotoxicosis in 146 patients, 19 per cent were hypothyroid and 1.4 per cent had relapsed 18 months after surgery. The incidence of postoperative hypothyroidism was lower in the younger patients (under 25 years). The absence of thyroid auto-antibodies preoperatively is an indication of a favourable result. The histological recognition of lymphocytic infiltration in the gland and the presence of thyroid auto-antibodies indicated an unfavourable outcome. Radioactive iodine gave an unpredictable response at therapeutic doses with 24 per cent relapsing in the first year after treatment. With ablative doses of radioactive iodine the incidence of hypothyroidism reached 94 per cent at 5 years after treatment. Surgery gives the best long-term results of the three treatment options and is the treatment of choice for the young, the severely toxic and those with toxic multinodular goitre.

[Surgical therapeutic concept of immune thyropathy]

73 patients with Graves' disease, surgically treated from 1975-1986, were investigated retrospectively. 43 patients, treated by subtotal thyroidectomy (Enderlen-Hotz) and a bilateral thyroid remnant of a total of about 8-12 g, were compared with 30 patients, treated by a modified subtotal thyroidectomy leaving a unilateral thyroid remnant of about 4-8 g, with respect to preoperative duration of disease, indications for surgical treatment, weight of resected specimens, operative complications and postoperative thyroid function. Surgical complications were similar in both groups. After subtotal thyroidectomy 14/43 patients (33%) displayed either recurrent hyperthyroidism (9/43, 21%) or local recurrence of Graves' goiter (3/43, 7%) or both (2/43, 5%). The modified subtotal resected group showed no recurrences of the disease. After subtotal thyroidectomy 11 patients were euthyroid without thyroid medication (26%) compared to only two patients (7%) after the modified procedure of subtotal thyroid resection. To prevent recurrences of goiter as well as hyperthyroidism and, on the other hand, to achieve euthyroid function postoperatively without need for thyroid replacement therapy, subtotal thyroidectomy with a small thyroid remnant of about 4-8 g is recommended for all patients with large goiter and a chronic recurrent course of the disease or with iodine induced thyrotoxicosis. Patients with non-recurrent Graves' disease but large goiter probably benefit from subtotal thyroidectomy with a larger thyroid remnant of about 8-12 g.

Surgery for thyrotoxicosis

Recent reports have suggested the use of radio-iodine for the treatment of all cases of thyrotoxicosis. This paper evaluates the results of 627 patients undergoing subtotal thyroidectomy with a mean follow-up of 5 X 8 years. The most common complications were hypothyroidism (26 X 6 per cent) and recurrent thyrotoxicosis (2 X 6 per cent). Permanent hypocalcaemia occurred in 8 cases (1 X 4 per cent) and one patient developed a permanent, though asymptomatic, unilateral cord palsy (0 X 2 per cent). Ultimately all patients receiving radio-iodine appear to become hypothyroid and there is continued worry about possible thyroid malignancy. Almost 70 per cent of our cases were free of complications and euthyroid and we therefore believe that surgery remains the treatment of choice for thyrotoxicosis. We also discuss the difference in results between Graves disease and toxic multinodular goitre.

Total thyroidectomy. A review of 213 patients

During a 10.5-year period ending in June 1982, total thyroidectomy was performed on 213 patients at the Vanderbilt University Medical Center. A nonfunctioning nodule on technetium scan was the primary indication for operation. Twenty-one of 213 patients had undergone previous partial thyroidectomy. The pathologic changes in the excised thyroids were carcinoma (81 patients), thyroiditis (27 patients), multiple benign adenoma (16 patients), thyrotoxicosis (27 patients), multinodular goiter (56 patients), and C-cell hyperplasia (three patients). Three total thyroidectomies were performed in search of a parathyroid adenoma. Fourteen patients had coexistent primary hyperparathyroidism. Excluding 12 patients with medullary carcinoma, 25% of all other patients with carcinoma would have had unrecognized tumor left in the remaining lobe had a total thyroidectomy not been performed. Calcium supplements were required in 59 patients during hospitalization, but only 2.8% of the patients developed permanent hypoparathyroidism. Since the adoption of Thompson's technique of total thyroidectomy, only one of the 128 patients (0.8%) has sustained permanent hypoparathyroidism. Two patients exhibited transient recurrent laryngeal nerve palsies without permanent nerve damage. There were no operative deaths. The low morbidity of total thyroidectomy appears to justify its use in all patients with differentiated thyroid malignancy. With surgeons experienced in this technique, total thyroidectomy should also be considered as the primary treatment for many other patients requiring thyroidectomy.

Serum thyroglobulin and its autoantibody following subtotal thyroid resection of Graves' disease

Thyroid surgery leads to marked changes of the levels of serum thyroglobulin and its autoantibodies in the subsequent 3 postoperative weeks. Furthermore in Graves' disease progression of exophthalmos has sometimes been seen following thyroidectomy. Nineteen medically pretreated patients with Graves' disease and no signs of exophthalmos were studied systematically up to 6 months postoperatively. Nine patients had thyroglobulin antibodies. Mean values rose to 3.5 times pretreatment values within 2 months (P less than 0.001) followed by a gradual fall below pretreatment level after 6 months. None of the antibody negative patients reverted to positive or vice versa. Serum thyroglobulin (n = 10) was elevated preoperatively (mean 309 micrograms/l, SD 251), their values being normalized within 1-2 months (mean 19.4 micrograms/l, SD 7.3). The preoperative serum thyroglobulin correlated to the weight of the removed thyroid tissue (r = 0.87, P less than 0.01). Three patients showed elevated thyroid stimulating hormone after 1 month. Of these, two developed myxoedema, the third remained euthyroid with persistently elevated serum thyroglobulin. None showed recurrence or developed exophthalmos within the period of observation. In spite of rising levels of thyroglobulin antibodies in all patients with antibodies none developed exophthalmos and only one patient with thyroglobulin antibodies had clinical myxoedema.

Hypothyroidism after thyroidectomy for Graves' disease

In 100 patients who underwent subtotal thyroidectomy for Graves' disease in 1970 through 1975, postoperative hypothyroidism developed in 75 patients an average of 4.6 months after operation. One patient had permanent hypocalcemia. Unilateral vocal cord function was abnormal postoperatively in three patients. Thyroidectomy for Graves' disease is used at our institution much less frequently than in the past and its use is being restricted to a younger population. The low recurrence rates of thyrotoxicosis (1 percent) was obtained at the expense of a high rate of postoperative hypothyroidism.