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

Effect of Microdissection of Inferior Thyroid Artery on Post-operative Hypocalcemia in Total Thyroidectomy

Hypocalcemia is one of the most common complication after bilateral thyroid surgery. Reported rates range from 5 to 35% and 0.5 to 4.4% for transient and permanent hypocalcemia respectively. Various methods have been devised to reduce the post-operative hypocalcemia and range from modification of surgical techniques to use of loops and avoidance of inadverant neck dissections. We conducted a randomised control trial of 50 patients divided into two groups, to evaluate the effect of microdissection and ligation of distal branches of inferior thyroid artery (group B) on incidence of temporary and permanent hypocalcaemia in patients of total thyroidectomy versus its ligation distally close to the thyroid capsule(group A). Postoperative mean total serum calcium levels were lower in group A as compared to group B (9.13 mg/dl vs. 9.33 mg/dl at 24 h; 8.77 vs. 9.10 at 3rd day and 8.58 vs. 8.96 mg/dl on 10 th day) with p > 0.05. The value of ionized serum calcium as recorded on 3rd day was 4.39 mg/dl for group A and 4.72 mg/dl for group B with p value ≤ 0.001 (Table 2). 19 patients in group A required calcium supplementation for 6 months with incidence of transient hypocalcemia at 76% while 11 patients in group B had calcium supplementation for 6 months with incidence of 40% and difference was significant statistically. Microdissection technique is better for preventing the temporary hypocalcemia and hence decreasing the hospital visits of the patient when compared to the ligation of inferior thyroid artery distally close to the thyroid gland. The incidence of permanent hypocalcemia doesn't varies significantly between both techniques.

Truncal vs Branch Ligation of Inferior Thyroid Arteries in Total Thyroidectomy: Does It Affect Postoperative Hypoparathyroidism?

OBJECTIVE

Postthyroidectomy hypoparathyroidism remains a significant challenge. Truncal ligation of the inferior thyroid arteries (ITAs) may lead to an increased risk of hypoparathyroidism; however, dissection along the thyroid capsule with branch ligation of the thyroid arteries could be a safer option. This study's objective was to compare the effect of truncal versus branch ligation of the ITAs on the rate of postoperative hypoparathyroidism.

STUDY DESIGN

Randomized prospective trial in line with the CONSORT guidelines.

SETTING

The study was conducted at a high-volume tertiary care setting.

METHODS

We randomized 319 patients into 2 groups: truncal ITA ligation (n = 157) and branch ITA ligation (n = 162). The primary outcomes were serum calcium and parathormone levels on the second postoperative day, followed by the levels on months 1, 3, 6, and 12. The need for exogenous replacements was noted. The secondary outcomes, such as operative time, blood loss, and other complications, were also recorded.

RESULTS

Our study revealed a significant difference in the incidence of transient hypocalcemia in patients undergoing truncal ITA ligation and branch ITA ligation (22.9% vs 3.1%, P < .05). The results showed that the levels of serum calcium and parathormone dropped on the second postoperative day and that 36 patients from the truncal ITA ligation group required exogenous calcium and vitamin D replacement. In contrast, only 5 patients from the branch ITA ligation group required the same.

CONCLUSIONS

This is the largest randomized trial of patients undergoing thyroidectomy, and it shows that dissection along the thyroid capsule with branch ligation of the ITAs is more likely to preserve parathyroid function as opposed to truncal ligation of ITAs.