Bilateral Truncal Ligation of the Inferior Thyroid Artery during Bilateral Subtotal Thyroidectomy Causes a Decrease in Parathormone without Clinically Manifest Hypoparathyroidism: A Randomized Clinical Trial.
BACKGROUND
Bilateral truncal ligation (BTL) of the inferior thyroid artery (ITA) is frequently used during subtotal thyroidectomy to reduce the risk of post-operative bleeding as well as to reduce the blood loss intra-operatively. However, its effect on parathyroid function has not been evaluated in relation to age, residual and resected thyroid volume.


METHODS
A total of 83 patients were randomized to receive non-BTL or BTL. After bilateral resection, the residual thyroid tissue on each side was measured by intra-operative ultrasonography. Laboratory and clinical examinations were performed the day before operation, intra-operatively and on post-operative days 2 and 5. The primary outcome measure was the difference in intact parathormone (PTHi) on post-operative day 5. Secondary outcomes were laboratory-diagnosed hypocalcaemia or hypoparathyroidism and clinically manifest hypoparathyroidism, respectively.


RESULTS
PTHi on post-operative day 5 was significantly lower in the BTL group (29.4 vs. 34.7 ng/l in the non-BTL group, p = 0.033), especially in 61- to 80-year-old patients (0 vs. -7.91 ng/l, p = 0.029). The biggest decline in PTHi was found in the BTL group (-14.067 ng/l PTH, p = 0.018) with a residual thyroid volume of 0.5-1.9 ml. There were two cases of asymptomatic hypoparathyroidism in each group (5.1 vs. 4.8%, respectively, p = 1.000). The only case of clinically manifest hypoparathyroidism was in a BTL group patient aged 64 years (2.4%, p = 1.000).


CONCLUSIONS
BTL of the ITA during subtotal thyroidectomy causes a larger decrease in PTH but does not lead to a significantly higher rate of clinically manifest hypoparathyroidism. BTL of the ITA, age >61 years, and a very small thyroid remnant (<2 ml) may be risk factors for post-operative hypoparathyroidism.
Department of Thoracic and Vascular Surgery, SRH Wald-Klinikum Gera, Teaching Hospital of Friedrich Schiller University of Jena, Gera, Germany.
Astrid
A
Kebsch
Utz
U
Settmacher
Thomas
T
Lesser
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001158:Arteries / Q000601:surgery; D005260:Female; D006044:Goiter, Nodular / Q000097:blood / Q000473:pathology / Q000601:surgery; D006801:Humans; D007011:Hypoparathyroidism / Q000097:blood / Q000209:etiology; D008026:Ligation / Q000009:adverse effects / Q000379:methods; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood* / Q000172:deficiency; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology; D013961:Thyroid Gland / Q000098:blood supply* / Q000601:surgery*; D013965:Thyroidectomy / Q000009:adverse effects* / Q000379:methods*; D055815:Young Adult
C470125:PTH protein, human; D010281:Parathyroid Hormone