|Year : 2018 | Volume
| Issue : 1 | Page : 46-48
Case report: An unusual variation in the course of recurrent laryngeal nerve in relation to the thyroid gland
Anjali Venugopal, Akanksha A Saberwal, Yogesh G Dabholkar
Department of ENT, D. Y. Patil Hospital and Research Centre, Nerul, Navi Mumbai, Maharashtra, India
|Date of Web Publication||23-Mar-2018|
Dr. Anjali Venugopal
701-A Wing, Apsara Building, Plot No. 51, Sector-17, Vashi - 400 703, Navi Mumbai, Maharashtra
Source of Support: None, Conflict of Interest: None
A complete understanding of the anatomic variations of the thyroid gland is necessary for a safe thyroid surgery. Injury to recurrent laryngeal nerve during thyroid surgery remains a significant source of morbidity. We present an uncommon variation in the position of right recurrent laryngeal nerve with the Tubercle of Zuckerkandl in a 40-year-old female who underwent thyroidectomy for a benign multinodular goiter. Identification and meticulous dissection of the Tubercle of Zuckerkandl and recognition of its association with the recurrent laryngeal nerve are essential to maintain the integrity of the nerve and prevent complications during thyroid surgery.
Keywords: Recurrent laryngeal nerve, Tubercle of Zuckerkandl, Thyroid surgery
|How to cite this article:|
Venugopal A, Saberwal AA, Dabholkar YG. Case report: An unusual variation in the course of recurrent laryngeal nerve in relation to the thyroid gland. Thyroid Res Pract 2018;15:46-8
|How to cite this URL:|
Venugopal A, Saberwal AA, Dabholkar YG. Case report: An unusual variation in the course of recurrent laryngeal nerve in relation to the thyroid gland. Thyroid Res Pract [serial online] 2018 [cited 2018 May 25];15:46-8. Available from: http://www.thetrp.net/text.asp?2018/15/1/46/228378
| Introduction|| |
An in-depth knowledge of neck anatomy and its variations is of utmost importance in thyroid surgeries. Anatomic variations of recurrent laryngeal nerve may threaten the safety of thyroid surgery. Injury to this nerve can cause symptoms ranging from hoarseness to respiratory distress.
The Tubercle of Zuckerkandl is a posterior projection from lateral thyroid lobe in the vicinity of the extralaryngeal termination of recurrent laryngeal nerve.,, Failure to remove it entirely may result in recurrent thyroid mass in cases of multinodular goiter, as seen after thyroidectomy.
Visual identification of this nerve remains the gold standard in reducing the incidence of injury.
| Case Report|| |
A 40-year-old female patient presented to the Department of ENT in our hospital with gradually progressive midline neck swelling of 2-year duration with euthyroid status.
On physical examination of the neck, a large thyroid mass of approximately 12 cm × 9 cm with no retrosternal extension, and cervical lymphadenopathy was noted. Ultrasonography and computed tomography of the neck showed multiple enlarged heterogeneous complex nodules suggestive of multinodular goiter with moderate tracheal lumen narrowing and no retrosternal extension. Fine-needle aspiration cytology showed evidence of colloid goiter with cystic changes. Preoperative laryngoscopic examination revealed bilateral mobile vocal cords.
After adequate preoperative routine blood investigations, she was posted for thyroidectomy. A midline collar incision (Kocher's) was taken. The strap muscles were separated in the midline and retracted laterally. Extracapsular dissection of thyroid was undertaken after ligation of vessels. The parathyroid glands were identified and preserved. After freeing and medially mobilizing the thyroid gland on the left side, the left recurrent laryngeal nerve was identified below the left inferior thyroid artery and had its usual recurrent course in the tracheo-oesophageal groove. On the right side, a posterior extension of tissue – Grade 3 Tubercle of Zuckerkandl was observed between the superior and middle thyroid lobe. The right inferior thyroid artery was identified and ligated and the gland was mobilized medially. The right recurrent laryngeal nerve was not found at its usual course with the right inferior thyroid artery. An exploration was made at the anticipated crossing point of the nerve and the artery. The right recurrent laryngeal nerve was found to be stretched over the tubercle of Zuckerkandl encircling it [Figure 1]. The right recurrent laryngeal nerve was carefully dissected and detangled from the tubercle on the right lobe. The distal part of recurrent laryngeal nerve returned back to its usual position after carefully dissecting the tubercle and Berry's ligament. Once the lobar dissection was completed, the superior pole was ligated and the gland delivered out and sent for histopathology examination [Figure 2]. Hemostasis was ensured and the wound was closed with a drain. The vocal cords were assessed by direct laryngoscopy before extubation which ensured mobility of both vocal cords.
|Figure 1: Right recurrent laryngeal nerve forming a loop around the Tubercle of Zuckerkandl|
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| Discussion|| |
The safety of thyroid operations mainly depends on the thorough knowledge of the embryology, anatomy, and topography of the thyroid gland and its related vascular and nervous structures and parathyroid glands including all potential variations. Hence, a thyroid surgeon must have intimate knowledge of all the structural and anatomic variants and relations of the gland. Preservation of the recurrent laryngeal nerve integrity is of paramount importance during thyroidectomy surgery. The localization and the identification of its course is of great importance during thyroid surgery.
The Tubercle of Zuckerkandl is a poorly known but common anatomic feature of the thyroid gland. It is defined as posterior extension of the lateral lobes composing of thyroid tissue according to Austrian anatomist Emil Zuckerkandl (1849–1910), who described it [Figure 3]a. Embryologically, it arises from the ultimobranchial body of the 4th branchial cleft. During organogenesis, the thyroid descends along the thyroglossal tract from the foramen cecum to the level of the thyroid cartilage, at which stage the right and left lobes develop. Moreover, there is a lateral component arises from the ultimobranchial body which fuses with the median component at the 5th week of gestation to complete the formation of the thyroid gland. The remnants of the ultimobranchial body, when present, persist as the tubercle [Figure 3]b., The tubercle of Zuckerkandl is classified into three grades according to size: grade 1: < 0.5 cm, Grade 2: 0.5 <1 cm, and Grade 3: > 1 cm.
An intimate knowledge of the lobe of Zuckerkandl is essential to perform safe thyroidectomy without injury to the vascular and nervous structures. It is described as being nearly always superficial to the recurrent laryngeal nerve, so serving as an accurate landmark for its identification in thyroid surgery.,, When enlarged by disease, the tubercle passes over the recurrent laryngeal nerve like a bridge. However, in our case, the nerve was found anteriorly to be looping around the enlarged tubercle. The resection of Zuckerkandl tubercle for total thyroidectomy requires refined and meticulous dissection adjacent to the nerve. Hisham and Lukman have previously reported that, in 6% of dissection, the recurrent laryngeal nerve was on the anterior surface of the tubercle and this course was at highest risk of injury., Recognition and removal of the tubercle is clearly important for the adequate performance of a total thyroidectomy. Depending on the size of the tubercle, this may result in a variable amount of thyroid tissue being left in situ. This remnant thyroid tissue may be a source of persistent radioiodine uptake on radioactive iodine scans, or even of recurrent thyroid mass in cases of multinodular goiter, as is seen after subtotal thyroidectomy.,, To prevent this, it is important to look for the Zuckerkandl tubercle and ensure that the entirety of this is removed with the thyroidectomy specimen.
Early identification of this structure and knowledge of its relationship with the recurrent laryngeal nerve and isolation of the nerve before dissection of tubercle are crucial for performing a safe thyroid surgery.
| Conclusion|| |
Visualization of the recurrent laryngeal nerve remains the main factor determining preservation of nerve function and a decreased incidence of recurrent laryngeal nerve paralysis in thyroid surgeries. To preserve the integrity of the recurrent laryngeal nerve, an in-depth knowledge of the Tubercle of Zuckerkandl and its relationship with the nerve is critical while performing total thyroidectomy.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
We would like to acknowledge the doctors and nursing staff in our department who participated in the treatment of this patient.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]