Practical tips to reduce complication rate in thyroidectomy

Claudio Cernea; Lenine G Brandão; Flávio C Hojaij; Dorival De Carlucci; Felipe Vanderlei; Renato Gotoda; Ana K Leite; Marco A V Kulcsar; Leandro L Matos; Rogério A Dedivitis; Vergilius J F Araújo-Filho; Marcos R Tavares

doi:10.4103/jhnps.jhnps_12_17

ORIGINAL ARTICLE

Year : 2017 | Volume : 5 | Issue : 1 | Page : 27-30

Practical tips to reduce complication rate in thyroidectomy

Claudio Cernea, Lenine G Brandão, Flávio C Hojaij, Dorival De Carlucci, Felipe Vanderlei, Renato Gotoda, Ana K Leite, Marco A V Kulcsar, Leandro L Matos, Rogério A Dedivitis, Vergilius J F Araújo-Filho, Marcos R Tavares
Department of Head and Neck, University of São Paulo Medical School, São Paulo, Brazil

Date of Web Publication

27-Jul-2017

Correspondence Address:
Claudio Cernea
Alameda Franca, 267, Cjto. 21, CEP 01422-000, Sao Paulo
Brazil

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jhnps.jhnps_12_17

Abstract

Introduction: Thyroid cancer is the most frequent endocrine neoplasm, and its incidence has been consistently rising during the last decades. Surgical treatment is the choice, but the complications can be truly devastating. Methods: The objective of this article is to present some practical tips to reduce the complication rate in thyroid surgery. Results: The more frequent complications during a thyroidectomy are mentioned, as well as practical tips to try to prevent them: acute airway compression, nerve injuries (both inferior laryngeal and external branch of the superior laryngeal nerves), and hypoparathyroidism. Conclusion: The prevention of complications during a thyroidectomy is imperative. The only way that the surgeon can assure the safety is to strictly adhere to technical principles, with diligent hemostasis, thorough anatomical knowledge, and gentle handling of the anatomic structures adjacent to the thyroid gland.

Keywords: Laryngeal nerves, parathyroid glands, thyroid neoplasms, thyroidectomy, upper airway obstruction

How to cite this article:
Cernea C, Brandão LG, Hojaij FC, De Carlucci D, Vanderlei F, Gotoda R, Leite AK, Kulcsar MA, Matos LL, Dedivitis RA, Araújo-Filho VJ, Tavares MR. Practical tips to reduce complication rate in thyroidectomy. J Head Neck Physicians Surg 2017;5:27-30

How to cite this URL:
Cernea C, Brandão LG, Hojaij FC, De Carlucci D, Vanderlei F, Gotoda R, Leite AK, Kulcsar MA, Matos LL, Dedivitis RA, Araújo-Filho VJ, Tavares MR. Practical tips to reduce complication rate in thyroidectomy. J Head Neck Physicians Surg [serial online] 2017 [cited 2023 Jun 4];5:27-30. Available from: https://www.jhnps.org/text.asp?2017/5/1/27/211724

Introduction

There are historical records of operations on the thyroid gland since ancient times. However, until the 19^th century, they were performed only in rare occasions, due to their unacceptable morbidity and mortality.^[1]

Emil Theodor Kocher published his revolutionary results with patients submitted to thyroid operations, demonstrating a surprising reduction of the complication rate.^[2] For his formidable contribution, Kocher was the first surgeon ever to receive the prestigious Medicine Nobel Prize, in 1909.

The main complications that can occur during or after a thyroidectomy are upper airway compromise, laryngeal nerves injuries, and hypoparathyroidism.

Upper Airway Compromise

Upper airway compromise can be caused by a very large thyroid growth causing deviation or even compression of the trachea, ultimately leading to respiratory distress. In this instance, awaken orotracheal intubation under endoscopic guidance may be advisable. However, in the event of distal tracheal stenosis, it is advisable to intubate the patient under a rigid bronchoscopy.

Usually, even very large retrosternal goiters can be uneventfully removed through the neck. Nevertheless, there are reports of respiratory insufficiency. Shen et al.^[3] studied sixty patients with retrosternal goiters; 98% were successfully excised only through the neck, but 12% of the patients presented with several respiratory complications, requiring prolonged intubation.

In general, respiratory distress is discovered immediately after the thyroidectomy. The most common causes are hematomas and bilateral vocal fold paralysis.

Hematomas

The thyroid gland has the most exuberant vascular supply of our body, proportionally to its volume. Hematomas are the most dangerous of the complications related to thyroidectomy. The frequency of postoperative hematoma varies from 0% to 3%.^[4] A relatively small hematoma may cause laryngotracheal compression, leading to laryngeal edema, obstruction, and ultimately, dead by asphyxiation. Thus, if the suspicion of a postoperative hematoma is raised, the surgical wound must be immediately opened at the bedside, enabling an evacuation of the hematoma. Only after releasing the pressure, the patient can be moved to the operation room in order to undergo a careful revision of the operative field. At this point, an emergency tracheostomy or cricothyroidostomy can be performed, but it is seldom necessary. It is important to emphasize that any attempt to insert an endotracheal tube without relieving the pressure caused by the hematoma is usually unsuccessful and dangerous. The prevention of hematomas must start before the operation. Clinical conditions that predispose to bleeding, as high blood pressure and hyperthyroidism, must be controlled preoperatively. The use of substances that interfere with the coagulation, such as aspirin and anticoagulants, have to be discontinued preoperatively. Intraoperatively, meticulous hemostasis is essential. Some sealing devices, such as the harmonic scalpel, help to control the blood loss during thyroidectomy despite the involved cost rise. Before closing the wound, it is important to carefully revise the hemostasis under pulmonary hyperpressure. Placement of drains before closing relies on the surgeon's preference. However, it is important to emphasize that the placement of a drain does not substitute zealous hemostasia and does not prevent the appearance of a life-threatening hematoma.^[4]

Inferior Laryngeal Nerve Injury

The inferior laryngeal nerve is the main motor nerve of the larynx. After leaving the superior mediastinum, it courses toward the larynx on the tracheoesophageal groove. It has a very intimate anatomical relationship with several important structures: the thyroid gland, the parathyroid glands, and the inferior thyroid artery. Obviously, it is at risk during operations involving the thyroid gland. Moreover, the inferior laryngeal nerve may present several anatomical variations: variable relationship with the branches of the inferior thyroid artery, extralaryngeal branching, and nonrecurrent inferior laryngeal nerve.

The relationship among the recurrent nerve and the branches of the inferior thyroid artery is quite variable.^[5],[6] Hence, it is not recommended to use the inferior thyroid artery as an anatomic landmark to identify the recurrent nerve.

Extralaryngeal branching of the inferior laryngeal nerve is rather common. Clearly, each branch must be carefully preserved, to ensure normal vocal fold function after the operation. Gregg^[7] and Katz and Nemiroff^[8] have reported this recurrent nerve branching in 61% and 63%, respectively, among the nerves they dissected in their operations (669 and 1177, respectively). In our own experience, including 2293 nerves, we also have found 63% of extralaryngeal branching.^[9]

The most dangerous anatomic variation is the nonrecurrent inferior laryngeal nerve. According to Sanders et al.,^[10] Stedman was the first author to describe this anomaly, in 1823. This variation can only be found on the right side unless the person has situs inversus totalis. In fact, Henry et al.,^[11] in 1988, reported 33 cases of nonrecurrent inferior laryngeal nerves, of which two were located on the left side, in patients with complete visceral inversion. The largest series of the literature was also published by the same group 15 years later,^[12] comprising 101 nonrecurrent inferior laryngeal nerves, observed during thyroidectomies and carotid endarterectomies. Preoperative suspicion of a nonrecurrent inferior laryngeal nerve was raised by finding an anomalous right subclavian artery with Doppler ultrasound. In the era of intraoperative nerve monitoring in thyroidectomy, we proved that it is possible to positively identify a nonrecurrent inferior laryngeal nerve using intermittent vagal nerve stimulation, before starting the actual dissection of the thyroid lobe. Two observations are very important: the finding of a very short latency and the absence of detectable complex below the point of exit of the nonrecurrent nerve.^[13]

Berry's ligament is certainly the area where the recurrent laryngeal nerve is in greater jeopardy. The nerve may be literally involved by this ligament, and an excessive medial traction eventually leads to neuropraxy.

The surgeon must be extra careful when he or she approaches right-sided large retrosternal goiters involving the right thyroid lobe the right side and extending to the posterior mediastinum. In this instance, the right recurrent nerve may be displaced anteriorly, assuming a potentially risky superficial location. The best way to avoid an iatrogenic injury is to identify the nerve near Berry's ligament, which is a very reliable anatomic landmark, and to extend the dissection caudally, before embarking in any maneuver to blindly dissect the thoracic goiter.

The intraoperative nerve monitoring is a very useful tool for identifying the nerve in reoperations and for documenting its functional integrity at the end of the lobectomy. The basic principles were established by Randolph in 2004.^[14] Basically, an orotracheal cannula with electronic sensors, which remain in contact with vocal folds, is used. A true intraoperative real-time contact electromyography of the intrinsic laryngeal muscles is obtained, in response to a neurophysiologic stimulus performed by the surgeon on the recurrent nerve. The obvious advantage is a clear documentation of the nerve integrity at the end of the lobectomy. However, its use in all cases is not universally accepted, due to the high cost, especially in countries on development. Nevertheless, many authors recommend its use in some specific situations: revision thyroidectomy, thyroid cancer, large lymph node metastasis, large and/or retrosternal goiters, hyperthyroidism, and previous neck irradiation.^[15],[16]

External Branch of the Superior Laryngeal Nerve Injury

The external branch of the superior laryngeal nerve is also a branch of the X cranial nerve. It bears a close anatomic relationship with the superior thyroid vessels, before turning medially toward the cricothyroid muscle, to provide its motor supply. Paralysis of this important branch causes decreased tension of the ipsilateral vocal fold, impairing the emission of high-frequency sounds, especially among women and voice professionals. The possibility of iatrogenic injury exists during dissection of the superior thyroid pole and ligature of the superior thyroid pedicle and has been underestimated.

This nerve is also known as “Galli-Curci” nerve. Amelita Galli-Curci was one of the leading sopranos during the 1930s. She underwent a thyroidectomy due to a 170 g goiter. Despite the use of local anesthesia and of the obvious extra care the surgeon took with her recurrent nerves (there are some rumors that he actually asked her to speak during the operation!), she was unable to produce high frequency notes anymore, probably due to bilateral injury of the external branch of both superior laryngeal nerves. She had to quit her brilliant career, with enormous impact on the press of that time.^[17]

We published an anatomic study in 1992, proposing a classification of the location of the external branch of the superior laryngeal nerve as related with the superior thyroid pole.^[18] More specifically, Type 2b nerves crossed the superior thyroid vessels below the upper border of the superior thyroid pole, increasing the risk of inadvertent damage even when the surgeon placed the ligatures on the caudal branches. In that series, 20% of the identified nerves were Type 2b. In a subsequent study, we performed a prospective double-blind randomized trial to evaluate the efficacy of identifying this nerve in thyroidectomies.^[19] In that clinical series, the only effective protection against nerve injury was its proactive search and possible identification. The frequency of Type 2b nerve was 14% in that clinical series. It is noteworthy that the frequency of the Type 2b external branch of the superior laryngeal nerve may rise considerably when dealing with very large goiters. We confirmed this hypothesis in a prospective clinical series including only very large thyroid growths (median weight of the specimens: 431 g), in which the frequency of the Type 2b external branch of the superior thyroid nerve escalated to 54%.^[20]

In everyday practice, generally, the surgeon within the operative field will encounter only one out of five nerves. Nevertheless, it is important to always keep in mind this possibility and to pay attention to preserve any transversal tiny nerve on the superior thyroid pole area. Magnification (I routinely use 4.2 wide-angled loupes) and some kind of nerve stimulation are essential, as the contraction of the cricothyroid muscle is easily visualized within the operative field. Furthermore, it is essential to try to place individual ligatures on the branches of the superior thyroid vessels as caudally as possible.

Hypoparathyroidism

The parathyroid glands are very small brownish structures, similar to a lentil, located adjacent to the thyroid gland. Their largest dimension varies from 6 to 8 mm and its weight oscillates between 20 and 50 mg. Normally, there are four glands, but the number may vary from 2 to 9. They are usually situated on the posterolateral aspect of the thyroid lobe, but they may actually occur on any site from the hyoid bone down to the superior mediastinum, including an intrathyroidal location. The location of the superior parathyroid gland is more predictable, posteriorly to the recurrent nerve, usually near to the superior thyroid pole. However, the location of the inferior parathyroid gland is more variable; often, it is positioned anteriorly to the recurrent nerve.

The thorough knowledge of the possible anatomic variations of the parathyroid glands is extremely important to avoid their inadvertent excision or devascularization. An intrathyroidal parathyroid gland may occur in as much as 7% of the patients.^[21],[22] We conducted an anatomic study in 56 nonpreserved cadavers, with a frequency of 5.6% of intrathyroidal parathyroid glands.^[23] Thus, we recommend opening the surgical specimen of all thyroidectomies still under sterile conditions, to enable identification with frozen section and immediate implantation of the resected gland in a cervical muscle, after carefully mincing it.

The parathyroid glands must be handled very carefully, to preserve their extremely fragile blood supply. The thyroid lobe must be dissected in a subcapsular plane, avoiding mass ligatures of the inferior thyroid artery, to avoid parathyroid gland ischemia. After completing the thyroid lobectomy, again the vitality of the ipsilateral parathyroid glands needs to be checked. If there is any doubt concerning their viability, it is preferable to reimplant them in a cervical muscle, after mincing them.

At the Service of Head and Neck Surgery of Hospital das Clinicas of the University of Sao Paulo Medical School, analyzing a series of >10,000 thyroidectomies, the frequencies of transient hypoparathyroidism (which resolved until 6 months) and permanent hypoparathyroidism, after total thyroidectomy, were 5.2% and 1.1%, respectively.^[24]

Some authors prefer to routinely give a calcium supplement, either intravenously or orally, to all patients submitted to total thyroidectomy. However, sampling blood parathyroid hormone levels 30 min after the end of the operation is very effective to predict postoperative parathyroid glands function, establishing the indication of calcium supplement when the blood levels are inferior to 15 pg/ml.^[25]

Conclusion

Thyroidectomy is a very safe operation, as long as the surgeon adheres to rigid technical principles. To keep the complication rate in very low levels, he or she must have a complete knowledge not only of the normal anatomy of the central visceral compartment of the neck but also of the common variations regarding the laryngeal nerves and the parathyroid glands.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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