Per Operative Study of Relation of Zuckerkandl Tubercle with Recurrent Laryngeal Nerve in Thyroid Surgery

The use of Zuckerkandl's tubercle as an anatomical landmark in identifying recurrent laryngeal nerve and superior parathyroid gland during total thyroidectomy: a prospective single-surgeon study

Objective

To determine the incidence and characteristics of Zuckerkandl's tubercle (ZT), and its relationship with recurrent laryngeal nerve (RLN) and the superior parathyroid gland (SPG) in the setting of total thyroidectomy.

Methods

A total of 421 patients (mean (min-max) age: 45.6 (18-78) years, 76.2% were females) who had total thyroidectomy were included in this prospective single-surgeon thyroidectomy series study. Patient demographics and thyroidectomy indications (benign and malignant) were recorded in each patient. The presence, grade and laterality of ZT, and its relationship with RLN and SPG were recorded during surgery.

Results

Most of the thyroidectomy indications (69.1%) were related to a malignant disease. The ZT was unrecognizable in 41(9.7%) of 421 patients. In 380 patients with identifiable ZT, the grade 2 (46.3%) ZT was the most common finding. Majority of ZTs (92.9%) were unilaterally located (right-sided: 64.9%; left-sided: 35.1%). In majority of the cases (83.2%), the RLN was found to lie medial to ZT. Overall, SPG was identified in close proximity to ZT in 66.6% of patients (Class 2 [0.5-1 cm from ZT] in 46.6% and Class 3 [<0.5 cm from ZT] in 20.0%). SPG was more likely to be identified in close proximity to ZT when the grade of ZT was higher, which was found to be located 0.5-1 cm from the ZT in 56.9% and 42.7% of grade 2 and grade 3 ZTs, respectively, and <0.5 cm from the ZT in 46.1% of grade 3 ZTs.

Conclusion

In conclusion, this prospective single-surgeon thyroidectomy series study indicates the likelihood of localizing the RLN medial to ZT, and the SPG in close proximity to ZT during total thyroidectomy operations. Hence, the ZT can be used as a reliable and constant landmark to localize both the RLN and the SPG during thyroid surgery, which enables minimizing the risk of iatrogenic injury to RLN, while ensuring a parathyroid-sparing thyroidectomy. The thyroid surgeon should have complete knowledge of thyroid gland anatomy and embryogenesis and should follow a careful and meticulous approach particularly for dissections around larger ZTs, given the increased likelihood of SPG and RLN to be in close proximity.

Extended Surgical Implication of Tubercle of Zuckerkandl in Total Thyroidectomy

The primary objective of the study was to assess the Tubercle of zuckerkandl (TZ) during thyroid surgeries and its relationship with RLN and Superior parathyroid (SP). A prospective study was done in, 30 consecutive cases of total thyroidectomy in whom per operatively TZ was identified. The presence of TZ, its laterality, size, relationship with RLN and parathyroid glands were documented. A grading system outlined by Pelizzo was applied in our current study. In majority of the cases the RLN was found to lie medial to TZ (26/30), followed by lateral position (3/30) and one case it was found to be posterior to TZ (1/30). The superior parathyroid was identified in close relation (< 2 cm) to the TZ in 27/30 cases. The distance between the TZ and SP was assessed. We proposed a classification for location of SP based on the distance between SP and TZ and also attempted to relate each class of SP location with TZ grade. There was strong association of Grade of TZ with the class of SP location (p value = 0.00046). TZ is constant surgical landmark with good reliability to identify the RLN and SP. RLN is found medial to TZ in majority of cases with few exceptions. SP is found to be closely associated with TZ in majority of cases and there is a strong relationship of proximity of SP and TZ with respect to TZ grade. Although this required further studies with larger population.

Can the Zuckerkandl tubercle assist in the location of the inferior laryngeal nerve during thyroidectomies?

OBJECTIVE

to evaluate whether the lateral projection of the thyroid gland, called Zuckerkandl's tubercle (ZT), can assist the surgeon in identifying the inferior laryngeal nerve during conventional open thyroidectomy.

METHODS

we conducted a prospective study with 51 patients submitted to thyroidectomy, with a total of 100 resected thyroid lobes, and observed the presence or absence of ZT in sufficient dimensions to be identified without image magnification, its base and height, its location in the gland, and its anatomical relationship with the inferior laryngeal nerve.

RESULTS

ZT was present in 68 of the 100 thyroid lobes analyzed (68%). The mean base was 6.7mm on the right side and 7.1mm on the left side, and the average height was 5.7mm on the right side and 6.1mm on the left side. In most of the lobes studied, the tubercle had a minimum height of 5mm (55.9%), with no significant difference between the right and left lobes of the thyroid gland. During surgery, 100% of the identified ZTs were anterior to the inferior laryngeal nerve, just below the nerve entry in the larynx.

CONCLUSION

the ZT is a quite frequent entity and large enough to serve as an intraoperative anatomical reference for the inferior laryngeal nerve, next to its entry in the larynx, along with other anatomical references.