Graves’ disease is the most common cause of hyperthyroidism [
Two different surgical techniques are used for the treatment of Graves’ hyperthyroidism: a total thyroidectomy (TT) and a subtotal thyroidectomy (STT), which leaves a small unilateral or bilateral remnant in situ. While there is general consensus that total thyroidectomy is the procedure of choice in patients with thyroid carcinoma, the optimal surgical approach for benign thyroid disease has remained controversial. The main reason for performing a subtotal thyroidectomy is a presumably lower incidence of postoperative complications, including recurrent laryngeal nerve (RLN) paralysis and hypoparathyroidism, and an anticipated postoperative euthyroid state by leaving a small remnant of thyroid tissue in situ to maintain adequate hormone production. There is, however, a risk that the disease will persist or recur in the remnant. More recent studies favoured TT as preferred procedure in the surgical management of Graves’ disease, because the residual function after STT was not as good as previously believed and the complication rates were not different between the TT and STT procedure [
The aim of this retrospective study was to evaluate the long-term treatment outcome of patients treated with subtotal thyroidectomy for Graves’ disease in our institution. We recorded postoperative thyroid function, along with the postoperative complication rates, to determine if subtotal thyroidectomy should still play a role in the surgical management of Graves’ hyperthyroidism.
All operation records of patients surgically treated for thyroid disease between January 1992 and December 2008 were reviewed to identify patients treated with subtotal thyroidectomy for Graves’ disease. Patients were diagnosed with Graves’ disease based on patient history, clinical examination, hormonal and/or immunologic assays, and thyroid scintigraphy. Charts, medical records, and correspondence of all departments involved in the treatment were retrospectively reviewed for data collection.
Patients were pretreated with antithyroid medication and/or with amiodarone, ipodate, or Lugol’s solution to achieve euthyroidism on the day of surgery.
Most operations before 2000 were performed by the same surgeon; thereafter, two additional surgeons also operated these patients. All three surgeons had extensive experience in thyroid surgery. For each subtotal thyroidectomy, a standard surgical technique was used. All patients underwent a unilateral subtotal hemithyroidectomy, leaving approximately 5–8 grams of thyroid tissue, and a contralateral total hemithyroidectomy.
Pre- and postoperatively, patients underwent direct laryngoscopy to check for vocal cord paralysis. Recurrent laryngeal nerve palsy was defined as permanent if it persisted more than 12 months postoperatively. Serum calcium levels were routinely measured four hours after surgery and at least once daily during hospital stay. Hypocalcaemia was defined as a serum calcium level <2.20 mmol/L (reference range 2.20–2.60 mmol/L). Oral or intravenous calcium and/or calcitriol suppletion was given when serum calcium level was <1.80 mmol/L and/or when symptoms developed. Permanent hypoparathyroidism was defined as requirement of calcitriol supplementation to maintain normal serum calcium levels 12 months after surgery.
Postoperatively, patients were assessed clinically and biochemically. Thyroid status was determined by measuring plasma thyroid-stimulating hormone (TSH): reference values 0.40–4.00 mU/L until 2007 and 0.50–5.00 mU/L as of 2008, free thyroxine (FT4): reference values 10–20 pmol/L until 1995 and 10–23 pmol/L as of 1996, and triiodothyronine (T3): reference values 1.30–2.70 nmol/L. Patients were classified as postoperative hypothyroid, in the case of FT4 levels below the reference range and/or elevated TSH levels on at least two consecutive measurements. These patients were prescribed thyroid hormone replacement therapy. Postoperatively persistent or recurrent elevated FT4 and/or T3 with suppressed TSH levels indicated hyperthyroidism. Euthyroidism was defined as a serum TSH within the normal range.
All patients were sent a questionnaire to ask them about their current need for thyroid hormone supplementation and the date on which it had been started. If patients did not return the questionnaire, general physicians or local endocrinologists were contacted to learn more about the patient’s current thyroid status and thyroid hormone use.
Each patient had a variable followup schedule, depending on the postoperative endocrine status, physician’s opinion, and patient preference. The followup was defined as the interval between thyroid surgery and the date on which the last known information on the thyroid functional status was retrieved.
The statistical package SPSS (version 16.0.2; SPSS, Inc., Chicago, IL) was used. Results are reported as median and range for interval variables. For nominal variables, numbers and percentages are given.
Patient characteristics.
Characteristic | |
---|---|
Age at diagnosis (years) | 32 (11–63) |
Age at surgery (years) | 34.5 (19–63) |
Time between diagnosis and surgery (months) | 26.5 (3–112) |
Sex | |
Female | 56 (90.3%) |
Male | 6 (9.7%) |
Surgical indication | |
Failed medical treatment | 54 (87.1%) |
Mechanical obstruction | 2 (3.2%) |
Cosmetic | 2 (3.2%) |
Patient preference/refusal radioactive iodine treatment | 2 (3.2%) |
Cold nodule | 1 (1.6%) |
Pregnancy wish | 1 (1.6%) |
Preoperative radioactive iodide treatment | |
No | 49 (79.0%) |
Yes | 13 (21.0%) |
Previous medical treatment | |
Antithyroid drugs (+ thyroxine + | 62 (100%) |
Duration of thyrostatic treatment(months) | 23 (4–73) |
Medical treatment at the time of surgery | |
Antithyroid drugs | 45 (72.6%) |
Antithyroid drugs + amiodarone, Lugols or ipodate | 11 (17.7%) |
Amiodarone | 1 (1.6%) |
Ipodate | 5 (8.1%) |
A total of 64 patients with a subtotal thyroidectomy for Graves’ hyperthyroidism were identified. Two patients were excluded because of histologically demonstrated malignancy of the thyroid gland requiring additional treatment. Therefore, 62 patients were analyzed.
Of the patients studied, 56 were women (90.3%) and 6 were men (9.7%), who were 34.5 (19–63) years of age at the time of surgical intervention. The interval from diagnosis to surgical intervention was 26.5 (3–112) months. The most frequent indication for surgery was failure of medical therapy (
Patients had a post-operative followup of 54.6 (2.1–204.2) months. Hypothyroidism occurred in 52 (83.9%) patients, 1.3 (0.2–34.2) months after surgery. In three patients postoperative hypothyroidism was diagnosed based on a high TSH with a normal free T4. From these 52 patients, the thyroid hormone status was based on recent data in 42 patients. We were unable to trace the remaining 10 patients, who were no longer with their last known general practitioner and whose current address was unavailable. These patients were discharged from further followup at the outpatient clinic 16.3 (0.7–69.7) months after surgery and 15.7 (2.1–70.9) months after being diagnosed with postoperative hypothyroidism. Four patients remained euthyroid during post-operative followup. Information on the thyroid status from the 4 euthyroid patients was retrieved 62.6 months after surgery (range 6.1–96.4 months). Six patients exhibited recurrent or persistent hyperthyroidism during the postoperative followup. The median time between the surgical treatment and the presence of hyperthyroidism was 9.7 months (range 1.1–86.3 months).
Permanent hypoparathyroidism was present in 2 (3.2%) patients. Only 1 (1.6%) patient developed permanent recurrent laryngeal nerve injury. There was no surgical mortality.
This study demonstrates that the majority of patients with Graves’ disease (83.9%) developed thyroid hormone deficiency after subtotal thyroidectomy. In addition, hyperthyroidism persisted or recurred in almost 10% of patients, whereas euthyroidism was established in only 6.5% of patients.
We compared our results to previously published studies evaluating thyroid status after subtotal thyroidectomy for Graves’ disease (Table
Thyroid function after subtotal thyroidectomy for Graves’ disease.
Study | Type of surgery | No. of patients | Followup | Postoperative thyroid function (%) | ||
Hypothyroid | Euthyroid | Hyperthyroid | ||||
Andaker et al. [ | BST | 23 | 3.6 (3-4) years | 34.8 | 60.9 | 4.3 |
STT | 27 | 3.6 (3-4) years | 44.4 | 55.6 | 0 | |
Chi et al. [ | BST | 166 | 21.1 | 69.9 | 9.0 | |
STT | 174 | 26.4 | 71.8 | 1.7 | ||
Chou et al. [ | BST | 205 | 44.2 | 48.7 | 7.0 | |
Ku et al. [ | BST | 119 | 65 (6–104) months | 72.3 | 21.8 | 5.9 |
Kuma et al. [ | STT | 67 | 32.9 | 56.7 | 10.4 | |
Lal et al. [ | STT | 30 | 6–120 months | 83.3 | 10.0 | 6.7 |
Le Clech et al. [ | STT | 312 | ? | 23.7 | 70.3 | 6.0 |
Lepner et al. [ | STT | 21 | 49 (24–70) months | 66.7 | 33.3 | 0 |
Miccoli et al. [ | STT | 80 | 6–48 months | 46.3 | 46.3 | 7.5 |
Moreno et al. [ | BST | 202 | 5 years | 62.1 | 35.5 | 2.4 |
Robert et al. [ | STT | 56 | 7 (1–15) years | 73 | 23 | 4 |
Sivanandan et al. [ | BST | 213 | 5 years | 28.2 | 56.8 | 15.0 |
Sugino et al. [ | STT | 728 | 42.5 (24–58) months | 46.4 | 39.0 | 14.6 |
Present study (2010) | STT | 62 | 55 (2–204) months | 83.9 | 6.5 | 9.7 |
The highest percentage of patients with euthyroidism is reported by Chi et al. [
The main reasons to perform a subtotal thyroidectomy are to prevent postoperative hypothyroidism and complications associated with the total procedure. Given that euthyroidism was achieved in only a minority of cases, the only remaining argument in favor of STT is the assumed lower complication rate. In our series, permanent hypoparathyroidism was present in 3.2% of our patients. Permanent hypoparathyroidism has been reported to range from 0.6% [
In conclusion, in our series on subtotal thyroidectomy for Graves’ hyperthyroidism euthyroidism was achieved in only a small proportion of patients. The majority of patients became hypothyroid after surgery, and approximately 10 percent had recurrent or persistent hyperthyroidism requiring additional treatment. These findings highlight the importance of continuing systematic evaluation of treatment results to optimize patient counseling. Our data favor total over subtotal thyroidectomy as the preferred surgical treatment for Graves’ hyperthyroidism.