Zuckerkandl tubercle in thyroid surgery: Is it a reality or a myth?

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.

Evaluation of thyroid Zuckerkandl tubercle by computed tomography

PURPOSE

This study investigated the incidence of thyroid Zuckerkandl Tubercle (ZT) using a computed tomography (CT) scan of the neck with contrast to identify the typologies in ZT-positive CT scans, investigate the presence of nodules located in that area, and compare the results with the relevant literature.

METHODS

We selected and retrospectively examined the CT scan images of patients who presented to our clinic with CT scans of the neck with contrast that clearly showed thyroid tissue and boundaries. Patients were evaluated based on age, gender, and presence of thyroid ZT. Patients with thyroid ZT were further investigated for localization and type of tubercles as well as for presence of nodules at the tubercle level.

RESULTS

A total of 1000 patients (mean age: 48.4 ± 19.1) were included in the study. Out of the total 222 (22.2%) patients who had thyroid ZT, 134 (60.4%) patients had unilateral thyroid ZT on the right side and 29 (13.1%) patients had unilateral thyroid ZT on the left side; 59 (26.6%) patients had bilateral thyroid ZT. In addition, nodules at the ZT level were observed in 13 (1.3%) of the patients. A review of all cases with ZTs indicated that 63% were Type 1, 31% were Type 2, and 5% were Type 3.

CONCLUSION

During the thyroid operations, ZT is essential for locating the recurrent laryngeal nerve. Reporting the presence of ZTs based on CT scans is crucial because it can prevent unnecessary interventional procedures, misdiagnoses, and likely complications in patients with planned thyroid operations.

The clinical significance of remnant thyroid tissue in thyroidectomized differentiated thyroid cancer patients on 131I-SPECT/CT

BACKGROUND

To explore the ¹³¹I-SPECT/CT characteristics of remnant thyroid tissue (RTT) in differentiated thyroid cancer (DTC), further assess the risk factors and clinical significance.

METHODS

52 DTC patients after total thyroidectomy had undergone neck ¹³¹I-SPECT/CT before ¹³¹I ablation. The diagnosis of RTT was based on SPECT/CT and follow-up at least 3 months. The anatomic locations and features of SPECT/CT of RTT were assessed by reviewers. The risk factors of RTT with CT positive were analyzed by the chi-square test.

RESULTS

A total of 80 lesions of RTT were diagnosed in this study, most of them were mainly located in the regions adjacent to trachea cartilage (37/80) or lamina of thyroid cartilage (17/80). On SPECT/CT of RTT, low, moderate and high uptake were respectively noted in 10, 24 and 46 lesions, definite positive, suspected positive and negative CT findings were respectively noted in 10, 21 and 49. The RTT lesions with definite positive CT findings were mainly located adjacent to lamina of thyroid cartilage (5/10). Primary thyroid tumor (P = 0.029) and T stage (P = 0.000) were the effective risk factors of CT positive RTT.

CONCLUSIONS

RTT has certain characteristic distribution and appearances on SPECT/CT. Most of RTT with definite CT abnormalities located adjacent to lamina of thyroid cartilage, which suggest surgeons should strengthen the careful removal in this region, especially primary thyroid tumor involving bilateral and T4 stage. This study can provide a certain value for the improvement of thyroidectomy quality in DTC patients.

Relation of Nonrecurrent Laryngeal Nerve with Zuckerkandl's Tubercle

The nonrecurrent laryngeal nerve (NRLN) is a rare anatomical variation of the recurrent laryngeal nerve (RLN) that may hinder the identification and preservation of this nerve during surgery and is associated with increased iatrogenic risks. Zuckerkandl's tubercle (ZT) is considered a useful reference for locating the RLN during thyroid surgery. We report the case of an asymptomatic patient with a 23 mm uninodular goitre suspicious for cancer. Ultrasound examination showed a hypoechoic nodule with regular contours and microcalcifications. The patient had normal thyroid-stimulating hormone and thyroxine levels, and aspiration biopsy was suspicious for follicular cancer. She was treated with total thyroidectomy after the intraoperative examination confirmed the presence of a papillary thyroid carcinoma. The standard approach to the RLN below the inferior thyroid artery was used on both sides. The nerve displayed anatomical variation in the nonrecurrent form (NRLN) on the right side and was associated with another variation that was not found in the consulted literature. It was completely surrounded by thyroid tissue in the region of ZT, and the surgeon was forced to remove it from within the thyroid tissue. This combination of anatomical variations seems to be quite rare. Knowledge of the anatomy of the RLN and its variations, as well as its identification and careful dissection, is essential to avoid injury to the nerve during surgical procedures.

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.

Thyroid Tubercle of Zuckerkandl May Not Arise from the Ultimobranchial Body: Results from Histological Analysis

Thyroid tubercle of Zuckerkandl (TZ) is a nodule arising from the posterolateral thyroid, considered to be a remnant of the ultimobranchial body (UB). Considering that C cells and solid cell nests also arise from the UB, we hypothesized that these would be present in the TZ. We examined the presence of C cells and solid cell nests in the TZ using the histological analyses of 21 patients with grade 2 or 3 TZs following Pelizzo's grading system. Out of 21 TZs, 19 (90.5%) were located in the right lobe of the thyroid. Microscopically, solid cell nests were found within the TZ in 1 case (4.8%), and within the main thyroid tissues in 3 cases (14.3%). Calcitonin-positive C cells were scattered within the TZ in 1 case (4.8%), and within the main thyroid tissue in 15 cases (71.4%). The distribution of C cells within the main thyroid tissue was denser than that within the TZ. The above-mentioned results indicated the lack of C cells and solid cell nests in the TZ. Although the TZ may have an embryological origin different from that of ordinary thyroid tissue, it is unlikely that the remnants of the UB are involved in the formation of the TZ.

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.

Zuckerkandl Tubercle of the Thyroid Gland: Correlations between Findings of Anatomic Dissections and CT Imaging

BACKGROUND AND PURPOSE

The Zuckerkandl tubercle is located at the posteromedial border of the thyroid lobe, and it may be confused with a neoplasm or other mass. This study was performed to clarify the position and morphologic characteristics of the Zuckerkandl tubercle by dissecting cadavers and to compare the findings with the corresponding CT images obtained in the same cadavers.

MATERIALS AND METHODS

One hundred thyroid lobes from 50 fresh cadavers were dissected for this study (20 males and 30 females; mean age at death, 77.3 ± 11.5 years). CT scans were obtained in 10 of the cadavers by using a 128-channel multidetector row CT scanner before dissection.

RESULTS

The Zuckerkandl tubercle of the thyroid gland was observed in 83% of the specimens. It was mostly located at the posteromedial border of the thyroid lobe and within the middle two quarters (2nd and 3rd) of the thyroid lobe. The Zuckerkandl tubercle was classified into 3 types based on its direction of extension: posteromedial in 64% of the specimens, posteromedial and superior in 13%, and posteromedial and inferior in 6%. On axial CT, the Zuckerkandl tubercle was usually continuous with the posteromedial part of the thyroid lobe and extended posteromedially to the esophagus. The parts of the Zuckerkandl tubercle that protrude posteromedially and superiorly or posteromedially and inferiorly from the thyroid lobe appeared separated from the thyroid gland by a thin, low-density string on axial CT.

CONCLUSIONS

Zuckerkandl tubercles that protrude toward the posteromedial and superior or inferior direction could cause confusion due to their separation when performing diagnoses with CT images.

Zuckerkandl's tubercle and its relationship to the recurrent laryngeal nerve: A cadaveric dissection and meta-analysis

OBJECTIVE

Zuckerkandl's tubercle (ZT), when present, is an anatomical landmark by which surrounding structures such as the recurrent laryngeal nerve (RLN) can be identified intraoperatively. This study aimed to investigate the prevalence and anatomical characteristics of Zuckerkandl's tubercle by combining cadaveric dissection with a meta-analysis.

METHODS

Through October 2016, an extensive search of PubMed, CNKI, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science was completed. Extracted data, along with the findings from our cadaveric dissections, were pooled into a meta-analysis to assess the prevalence and size of ZT and its relationship to the RLN.

RESULTS

The pooled prevalence estimate of a ZT was 70.2% in the general population, 65.0% of which were considered Grade 0 tubercles (<1.0cm) and 35.0% Grade 1 (≥1.0cm). The RLN ran posteromedially to the ZT in 82.7% of cases, laterally to it in 8.7%, and on top of it in 8.6% of hemilarynges.

CONCLUSION

RLN palsy is a common postoperative complication and cause for litigation following neck surgery. The ZT is a common component of the thyroid gland and with proper knowledge, surgeons can use it to reliably and quickly identify the RLN during operative procedures.