Reality of Zuckerkandl tubercle and relationship with other anatomical variations

The tubercle of Zuckerkandl (TZ) is considered to be the fusion point of the ultimabranchial body and the median thyroid body. We aimed to evaluate the frequency of TZ and its relationship with other anatomical variations and recurrent laryngeal nerve (RLN) paralysis.

Data regarding the thyroid lobe and RLN of patients with thyroidectomy between June 2016 and December 2019 were retrospectively evaluated. TZ is classified according to its dimensions as follows: category 0; invisible, category 1; thickening only the lateral to thyroid lobe, category 2; ≤1 cm, and category 3; >1 cm. Categories 2 and 3 were accepted as TZ.

In 627 patients, 1011 necks and thyroid lobes were evaluated. TZ was found as 58.9% in categories 0 and 1, 18.7% in category 2%, and 22.4% in category 3. In the presence of TZ, the RLN was located posteromedially in 95.2% and laterally in 4.8%. RLN entrapment in the Berry ligament region was significantly higher in categories 2 and 3 compared to category 1 (25.4% vs. 28% vs. 17.3% and p < 0.0001). There was no significant difference in RLN paralysis based on the presence and size of TZ or the relationship between RLN and TZ.

TZ is not rare and can be observed in 41.1% of thyroid lobes. It should be noted that the likelihood of RLN entrapment in the Berry region is higher in categories 2 and 3. Therefore, performing TZ dissection without applying traction to the thyroid lobe and mapping RLN could contribute to better RLN preservation.