EVALUATION OF TUBERCLE OF ZUCKERKANDL AS A LANDMARK FOR RECURRENT LARYNGEAL NERVE AND SUPERIOR PARATHYROID GLAND AND ITS IMPLICATIONS ON COMPLETE REMOVAL OF THYROID

Abstract

BACKGROUND: Thyroidectomies are a commonly performed surgery in our institution and preservation of Recurrent laryngeal nerve and parathyroid glands is an important & delicate part of the surgery. A small posterior extension of thyroid gland near the - ligament of Berry is called as tubercle of Zuckerkandl. Zuckerkandl’s tubercle, is an anatomical landmark by which surrounding important structures such as - the recurrent laryngeal nerve can be identified during the surgery. Various studies have been carried out to find out the relationship between tubercle of Zuckerkandl and recurrent laryngeal nerve. However, complete dissection of this thyroid tissue (tubercle of Zuckerkandl) can be challenging due to its close relationship to recurrent laryngeal nerve and dense fascia in this region. This can significantly affect the outcome in thyroid malignancies. In this study we intend to document the impact of size & shape and as well as the relationship of tubercle of Zuckerkandl to recurrent laryngeal nerve and superior parathyroid gland and the reliability of this structure as a surgical landmark & its effect on complete removal of thyroid tissue in this region. This study will therefore help in understanding the surgical anatomy of tubercle of Zuckerkandl & help to develop all possible approaches for complete removal of thyroid lobe without increasing morbidity. It also helps us in understanding that the excision of the tubercle requires fine and meticulous dissection with utmost care because of its close relationship to recurrent laryngeal nerve and superior parathyroid gland. OBJECTIVES: 1. To document the prevalence of tubercle of Zuckerkandl in patients undergoing total or hemi thyroidectomies. 2. To document size and shape of tubercle of Zuckerkandl and its relationship to recurrent Laryngeal nerve and superior parathyroid gland during total or hemi thyroidectomies. 3. To document usefulness of tubercle of Zuckerkandl as a surgical landmark for recurrent laryngeal nerve & difficulties encountered in its complete removal. MATERIALS AND METHODS: It is a cross- sectional observational study where 60 patients planned for total and hemi thyroidectomy in the Department of Otorhinolaryngology for the study at R.L.Jalappa Hospital & Research Centre, Tamaka, Kolar from December 2019 to July 2021 were taken study after fulfilling the inclusion criteria and signing an informed consent. In all patients undergoing hemi and total thyroidectomies, the size and shape of the tubercle of Zuckerkandl were measured using a sterile caliper. The distance between tip of tubercle of Zuckerkandl and recurrent laryngeal nerve were measured in millimeters using the tip of the sterile caliper. We documented whether the tubercle of Zuckerkandl was overlying the recurrent laryngeal nerve or not. Distance between tip of Zuckerkandl tubercle with superior parathyroid gland were documented. The difficulty in separating Zuckerkandl tubercle from adjacent structures like recurrent laryngeal nerve, branches of inferior thyroid artery & Berry’s ligament were documented by noting the time taken & bleeding at this site. Statistical analysis: Data was entered into Microsoft excel data sheet and was analyzed using SPSS 22 version software. Categorical data was represented in the form of Frequencies and proportions. Chisquare test was used as test of significance for qualitative data. Continuous data was represented as mean and standard deviation. Graphical representation of data: MS Excel and MS word was used to obtain various types of graphs such as bar diagram, Pie diagram. p value (Probability that the result is true) of <0.05 was considered as statistically significant after assuming all the rules of statistical tests. Statistical software: MS Excel, SPSS version 22 (IBM SPSS Statistics, Somers NY, USA) was used to analyze data. RESULTS: Majority of subjects were in the age group 41 to 50 years (43.1%). TZN was identified in all of the cases (100%). Grade I and II together constituted about 96.1% of all TZN. TZN is like an arrow pointing towards the RLN & if mobilized medially it allows easy identification of the nerve before it turns below the inferior cricothyroid joint. TZN in all cases was pyramidal in shape and all RLN ran either anterior or medial to the TZN. The TZN was lying anterior to Recurrent laryngeal nerve in 7 cases (6.9%). The tubercle was lying medial to Recurrent laryngeal nerve in 95 cases (93.1%). More than 50% of the cases took an average time between 8 to 10 minutes for dissecting the TZN from its underlying structures & the remaining 36% cases took more than 10 minutes. Blood loss at the site of dissection was found to be not significant. CONCLUSION: Tubercle of Zuckerkandl is a consistent and a sturdy structure which is identified in majority of cases. The TZN is a useful guide when it comes to identification of RLN. Surgeons should be well aware about the incidence, shape, grade and its relation to RLN when it comes to thyroidectomies. Thus it is a very useful landmark in thyroid surgery for saving the Recurrent laryngeal Nerve.