The Zuckerkandl tubercle: problematic or helpful in thyroid surgery?

Protect the recurrent laryngeal nerves in US-guided microwave ablation of thyroid nodules at Zuckerkandl tubercle: a pilot study

BACKGROUND

To evaluate the safety and efficacy of US-guided microwave ablation in patients with thyroid nodules at Zuckerkandl tubercle.

METHODS

103 consecutive patients with thyroid nodules at Zuckerkandl tubercle (ZTTN) were enrolled in this study from November 2017 to August 2021. Prior to the surgery or US-guided microwave ablation (MWA), preoperative ultrasound visualization of the recurrent laryngeal nerve (RLN) and ZTTN was performed, the size and the position relationship between them were observed. Patients were followed up at 1, 3, 6, and 12 months after MWA and the volume reduction rates (VRR) of the thyroid nodules were analyzed.

RESULTS

All patients successfully had the RLN and ZTTN detected using ultrasound before surgery or ablation with a detection rate of 100%. For the 103 patients, the majority of ZTTN grades were categorized as grade 2, with the distance from the farthest outside of ZTTN to the outer edge of thyroid ranging between 6.0 and 10.0 mm. The position relationship between ZTTN and RLN was predominantly type A in 98 cases, with type D observed in 5 cases. After MWA, the median nodule volume had significantly decreased from 4.61 (2.34, 8.70) ml to 0.42 (0.15, 1.41) ml and the VRR achieved 84.36 ± 13.87% at 12 months. No nodules regrew throughout the 12-month follow-up period. Of the 11 patients experienced hoarseness due to RLN entrapment before ablation, 7 recovered immediately after separation of the RLN and ZTTN during MWA, 2 recovered after one week, and the other 2 recovered after two months.

CONCLUSIONS

The RLN is closely related to ZTTN and mainly located at the back of ZTTN. The RLN can be separated from ZTTN by hydrodissection during MWA. US-guided MWA is a safe and effective treatment for ZTTN.

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.

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.

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

To identify Zuckerkandl tubercle and to determine relationship between the recurrent laryngeal nerve and Zuckerkandl tubercle (ZT). Peroperative study. Intraoperatively Zuckerkandl tubercle was identified. Size of the thyroid lobe and Zuckerkandl tubercle were co-related and direction of tubercle in relation to recurrent laryngeal nerve was examined. Grading of tubercle on the basis of size was done. We studied its direction and relation with recurrent laryngeal nerve. ZT was identified in 87.86% (179 out of 206) of cases. In the study amongst the 179 cases in whom ZT could be identified, ZT was found on the right side (85.41% i.e. 123 out of 144), 81.41% (92 out of 113) to the left side and 15.68% (8 out of 51) were B/L. ZT was found posterior to the tubercle in 97.22%(175 out of 179) cases and anterior to the tubercle in 2.77% (5 out of 179) cases. The relationship between recurrent laryngeal nerve and ITA was studied. ITA was anterior to RLN (in 70.89%) and posterior to RLN in 29.10%. Thus, ZT is an important landmark for identification of RLN during thyroidectomy (p value 0.001). Level of evidence III.

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.

The Tubercle of Zuckerkandl : An Important Landmark Revisited

To study the incidence of the tubercle of Zuckerkandl (ZT) among Indian patients subjected to thyroid surgery at a tertiary care cancer centre and its relevance in localization of recurrent laryngeal nerve (RLN). Prospective study on 144 patients (48 males, 96 females) undergoing thyroidectomy (35 hemithyroidectomies, 109 total thyroidectomies) from September 1st 2010 - February 28th 2013. 144 specimen/253 lobes (129 right, 124 left) were evaluated. Findings were recorded by the same team to ensure consistency. Presence, shape, grade (Pelizzo's) of ZT and relationship to RLN were documented. ZT was identified in 90.5 % (n = 229), commoner on the right (n = 120) than on left (n = 109). ZT was Grade 0 in 9.5 %, Grade I in 28.9 %, Grade II in 50.5 % and Grade III in 11 % of cases. In all patients ZT was unilobed. Recurrent laryngeal nerve (RLN) was consistent in position and was posterior to ZT in all cases. There were no branches of the RLN above the ZT. The ZT is a useful guide in locating RLN. Surgeon should be aware about the incidence, shape, grade and relation to RLN which is different in the Indian population as compared to what has been reported globally.

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

Background

Zuckerkandl tubercle (ZT) is a lateral projection from the lateral thyroid lobe which is a constant landmark for finding the recurrent laryngeal nerve during thyroid surgery. It is the condensed thyroid parenchyma located in the cricothyroid junction. Even today, ZT and its relationship with recurrent laryngeal nerve (RLN) is not well known by all surgeons. The objectives of the present study were to find out the incidence of ZT in our thyroidectomies and to investigate whether the ZT has a relationship with RLN. We also discussed how to prevent RLN injury during thyroidectomy.

Materials and methods

One hundred operations were performed by the same surgeon included in this study. All operations performed with intraoperative neuromonitorization (IONM) for proving the visualization of RLN. In each patient, particularly the ZT and its relationship with RLN searched and recorded. We also analyzed the patients in terms of sex, age, clinical diagnosis, and types of performed operations.

Results

In 100 operations, 173 thyroid lobectomies were considered. 87 of these lobectomies were in right side and 86 in left side. The ZT was determined in 127 of 173 (73.41%) lobectomies. ZT was detected in 68 (78.16%) of right thyroid lobes whereas in 59 (68.60%) of left thyroid lobes. We observed that the ZT was detected more frequently in the right side. In 115 (90.55%) of these occasions, the recurrent nerve was directed upwards covered by the ZT.

Conclusions

If it is present, ZT is a real constant landmark pointing to the RLN. In order to find and protect RLN during thyroid surgery, a careful, bloodless, and meticulous dissection should be carried out around the ZT. Although our results are encouraging, further researches are still needed on this topic.

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Zuckerkandl tubercle (ZT) is a lateral projection from the lateral thyroid lobe.

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Even today, ZT and its relationship with recurrent laryngeal nerve (RLN) is not well known by all surgeons.

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If it is present, ZT is a real constant landmark pointing to the RLN.

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In order to find and protect RLN during thyroid surgery, a careful dissection should be carried out around the ZT.

Novel thyroidectomy difficulty scale correlates with operative times

BACKGROUND

The aim of this study was to evaluate a new thyroidectomy difficulty scale (TDS) for its inter-rater agreement, correspondence with operative times, and correlation with complications.

METHODS

We developed a four item, 20-point TDS. Following cases where two board-certified surgeons participated, each surgeon completed a TDS, blinded to the other's responses. Paired sets of TDS scores were compared. The relationship between operative time and TDS scores was analyzed with linear regression. Multiple regression evaluated the association of TDS scores and other clinical data with operative times.

RESULTS

A total of 119 patients were scored using TDS. In this cohort, 22.7% suffered from hyperthyroidism, 37.8% experienced compressive symptoms, and 58.8% had cancer. The median total TDS score was 8, and both surgeons' total scores exhibited a high degree of correlation. Overall, 87.4% of the two raters' total scores were within one point of each other. Patients with hyperthyroidism received higher median scores than euthyroid patients (10 vs. 8, p < 0.01). Similarly, patients who suffered a complication had higher scores than those without complications (10 vs. 8, p = 0.04). TDS scores demonstrated a linear relation with operative times (R2 = 0.36, p < 0.01). Cases with a score of ≥14 took 41.0% longer compared to cases with scores of ≤5 (p < 0.01). In the multiple regression analysis, TDS scores independently predicted the operative time (p < 0.01).

CONCLUSION

The TDS is an accurate tool whose scores correlate with more difficult thyroidectomies as measured by complications and operative times.

Zuckerkandl's tubercle of the thyroid gland: Its location in the anatomical position, and comparative morphology of the same specimens before and after fixation

The aim of this study was to elucidate the definition of the borders and surface of the thyroid lobe in the anatomical position, and to compare the morphology of Zuckerkandl's tubercle (ZT) in the fresh and fixed states. One hundred thyroid lobes from 50 fresh Korean cadavers were used. The lateral border of the thyroid lobe could be defined as the most lateral margin of its anterior aspect when in the anatomical position. The posteromedial border was the margin that projected toward the trachea or tracheoesophageal groove. The lateral and posteromedial borders, and the posterior surface between these borders, could be identified in most of the fixed cadavers. The posterolateral border could only be identified in the thyroid lobe if there was compression by the internal carotid artery in cross-sectioned specimens and CT images. The ZT was identifiable in 85% of both fresh and fixed specimens. It was identified mainly at the posteromedial border of the thyroid lobe when in the anatomical position, and extended to the tracheoesophageal groove or esophagus. In the fresh state, the ZT projected as a rounded cone with a usually semicircular base, but its shape was very variable in the fixed state. In the present study, the ZT was found at the posteromedial border or posterior surface of the thyroid lobe in both the fresh and fixed states, contrary to most previous reports. The location of the ZT should be established in the anatomical position to avoid confusion.