The nonrecurrent inferior laryngeal nerve: review of 33 cases, including two on the left side

In 6307 cervicotomies for thyroid and parathyroid excision, 33 cases of nonrecurrent inferior laryngeal nerve were identified (0.52%). The anomaly was observed in 31 cases from 4921 dissections on the right side (0.63%) and in two cases from 4673 dissections on the left side (0.04%). Of the 31 patients who were initially seen with this anomaly on the right side, no innominate (brachiocephalic) artery was found; the right common carotid artery was arising directly from the aortic arch. The aberrant subclavian artery could always be felt against the vertebral column behind the esophagus. The two patients with the anomaly on the left side had a right aortic arch associated with situs inversus viscerum. In one case of invasive thyroid carcinoma, the nerve had to be sacrificed. In all of the other patients, postoperative laryngoscopic findings were normal. The nervous anomaly was of vascular anomaly origin in all cases. Predisposing factors for its onset during aortic arch development are discussed. Before surgical treatment, the diagnosis may only be made if vascular anomaly is suspected. Impairment of swallowing is the only clinical symptom to be looked for. The retroesophageal subclavian artery may be detected on chest x-ray films (20%) or by the compression and distortion of the esophagus shown during barium swallow tests (97%). Although rare on the right side and exceptional on the left, an aberrant nonrecurrent pathway for the inferior laryngeal nerve represents a major surgical risk. This is an additional argument in favor of systematic dissection of the inferior laryngeal nerve during thyroid or parathyroid excision.     

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??Preoperative prediction and intraoperative treatment of nonrecurrent laryngeal nerve ZHANG Ping, ZHANG Hao??LI Xuan,et al. Department of General Surgery, the First Hospital of China Medical University, Shenyang 110001, China.
Corresponding author: ZHANG Hao??E-mail: haozhang@mail.cmu.edu.cn
Abstract Objective To evaluate preoperative judgment and intraoperative identification of nonrecurrent laryngeal nerve (NRLN) during thyroidectomy. Methods The clinical data of 4 cases of thyroid surgery associated with a right NRLN from August 2008 to February 2010 in the Department of Vascular and thyroid, the First Hospital of China Medical University were analyzed retrospectively. Results The preoperative CT scan showed a retroesophageal aberrant right subclavian artery in all 4 cases. They had identification of Type??A NRLN on the right side. Postoperatively, the patient had normal vocal cord function on laryngoscopy. Conclusions It is possible to predict preoperatively a right NRLN by identifying an aberrant right subclavian artery on the CT film of the neck, which likely enabled the prevention of vocal cord paralysis.     

Esophageal carcinoma with nonrecurrent inferior laryngeal nerve

Occurrence of a nonrecurrent inferior laryngeal nerve is quite rare. We present the case of a 70-year-old man with carcinoma of the esophagus. An abnormal right subclavian artery was detected preoperatively. This anomaly suggested that the right inferior laryngeal nerve branched directly from the vagal trunk. A carcinoma of the esophagus was resected, and lymph nodes were dissected. The right inferior laryngeal nerve was fully preserved, and the esophagus was primarily repaired.     

Esophagectomy with three-field lymph node dissection for esophageal carcinoma with a nonrecurrent inferior laryngeal nerve

In rare cases, the inferior laryngeal nerve branches directly from the vagus trunk. A 58-year-old man with carcinoma of the thoracic esophagus was referred to our hospital. A nonrecurrent anomaly of the right recurrent laryngeal nerve associated with an aberrant right subclavian artery was detected preoperatively by computed tomography and magnetic resonance imaging. This artery ran on the right side between the esophagus and the vertebral column. Recognition of this nerve before upper mediastinal lymph node dissection was thought to be important for avoiding unexpected neural injuries. For a successful esophagectomy with three-field lymph node dissection in patients associated with this anomaly, a cervico-abdominal procedure followed by a thoracic procedure, which is the reverse of the usual process, could be useful for a safe operation. However, this anomaly made it difficult to dissect lymph node along the left recurrent laryngeal nerve.     

Coexisting right nonrecurrent and right recurrent inferior laryngeal nerves: a rare and controversial entity

Variations in the course of the recurrent laryngeal nerve (RLN) can occur, including the development of a nonrecurrent inferior laryngeal nerve (NRILN). Rarely, both a right RLN and a right NRILN have been reported in the same patient, merging before they enter the larynx. A case is presented, including images, and the literature concerning this rare anatomical finding is reviewed, including studies suggesting alternative explanations for these cases. Fourteen previously reported cases of coexisting RLN and NRILN were identified, all involving the right side. Some cases were associated with an anomalous origin of the right subclavian artery and some were not. The alternative explanations that a communicating branch of the sympathetic nerve, which joins the RLN, is mistaken for an NRILN or that a collateral branch from an NRILN is mistaken for an RLN in these cases are also considered. Surgeons must be aware of these unusual variations to minimize nerve injury during neck surgery.     

Benign anatomical mistakes: the correct anatomical term for the recurrent laryngeal nerve

The term recurrent laryngeal nerve has been adopted by Nomina Anatomica (1989) and Terminologia Anatomica (1998) to describe this vagus branch from its origin, its turn dorsally around the subclavian artery and the aortic arch, and its cranial pathway until it reaches its terminal organs in the neck. However, there is still much confusion, and either the terms inferior and recurrent laryngeal nerve are used interchangeably or inferior laryngeal nerve is considered the terminal branch of the recurrent laryngeal nerve. We hereby feel that it is necessary to reassess the term and we propose the term inferior laryngeal nerve for the entire nerve under consideration, from its origin from the vagus nerve to its destinations, including tracheal, esophageal, and pharyngeal branches. If the term superior laryngeal nerve is a given, standard and accepted term in the anatomical terminology, then logically the term inferior laryngeal nerve should also be accepted, as opposed to it. Of course the upward travel of the inferior laryngeal nerve is "recurrent". When nonrecurrence is encountered together with an arteria lusoria, a retroesophageal right subclavian artery or a right aortic arch, we consider that the term nonrecurrent inferior laryngeal nerve should be used to describe the deviation from the normal.     

Nonrecurrent inferior laryngeal nerves and their association with a recurrent branch

Seven cases of nonrecurrent inferior laryngeal nerves have been presented from a review of 1,000 consecutive thyroidectomies over a 20 year period. In two of these seven cases, both a nonrecurrent nerve and an additional recurrent branch were present on the right side. This double nerve presentation has not been described before. Unless one is aware of this possibility, one might inadvertently injure the major nonrecurrent trunk, having identified only a small recurrent branch. We emphasize the need for a complete nerve identification technique.     

A safe technique for thyroidectomy with complete nerve dissection and parathyroid preservation

A series of 1,000 consecutive thyroid operations is presented, without a case of permanent recurrent laryngeal nerve injury. Emphasis is placed on the identification of variations and complete dissection of the recurrent laryngeal nerve, including peripheral branches and technical aspects of the dissection. Sixty-five percent of the cases had multiple terminal branches of the recurrent laryngeal nerve and five cases on the right side had a nonrecurrent course. A low incidence of hypoparathyroidism is presented, due in part to the avoidance of ligating the inferior thyroid artery in continuity and the technique of extracapsular dissection of the thyroid gland. The external branch of the superior laryngeal nerve was protected by the early mobilization of the superior thyroid vessels and ligatures placed flush on the capsule of the superior pole.     

Nonrecurrent laryngeal nerve during carotid artery surgery: case report and literature review

The anomalous position of a nonrecurrent inferior laryngeal nerve predisposes it to injury during surgery in the neck. We present the case of a patient who underwent a carotid endarterectomy in which a rare left nonrecurrent laryngeal nerve was found intraoperatively. This abnormality, which occurs much less often on the left than the right side of the neck, should be familiar to vascular surgeons. Historical, embryologic, and surgical significance of this anomaly is addressed.     

Diagnostic complexities and anatomical surprises in a case of thyroid surgery for papillary carcinoma

We present the case of a male patient who needed surgery for a large undefined submandibular schwannoma and a small contralateral thyroid carcinoma associated with cervical lymph nodes of a dubious nature. During the operative procedure all the pathological conditions were resolved, with some remarkable surprises. A non-functioning parathyroid adenoma was found and removed. A fairly unusual anatomical complication was also detected with regard to the right inferior laryngeal nerve, i.e. an anastomotic branch connecting the main trunk to the vagus nerve.     

Zuckerkandl's tuberculum: could it be useful in thyroid surgery?

A thorough knowledge of thyroid anatomy could reduce the incidence of lesions to the inferior laryngeal nerve. In view of its relationship with the recurrent laryngeal nerve and the parathyroid gland, Zuckerkandl's tuberculum should be considered an anatomical landmark for the recurrent laryngeal nerve in thyroid surgery. The aim of the study was to verify whether the identification of Zuckerkandl's tuberculum could be useful to reduce the incidence of recurrent laryngeal nerve lesions. Four hundred and thirty-two patients underwent thyroid surgery over the period from January 2001 to December 2003 for benign (377 patients) or malignant disease (55 patients). Three-hundred and forty-eight (81%) underwent total thyroidectomy. Zuckerkandl's tuberculum was found in 74.5% of patients, with a high prevalence in the right lobe: in 5% of patients it was grade I, in 50% grade II and in 45% grade III. Its presence was associated with the recurrent laryngeal nerve in almost all cases. Eight of the patients undergoing total thyroidectomy suffered recurrent nerve paralysis, only 4 of which proved definitive. Identification of Zuckerkandl's tuberculum allows safer isolation of the recurrent laryngeal nerve and superior parathyroid gland dissection.     

Identification of the Nonrecurrent Laryngeal Nerve during Thyroid Surgery: 20-Year Experience

The nonrecurrent laryngeal nerve, which is rarely observed during thyroidectomy, is at high risk for damage. During a 20-year period 6000 thyroidectomies were performed at our institution, and during these operations inferior laryngeal nerves were routinely identified in all the patients with a standard procedure based on the usual anatomic landmarks. A nonrecurrent laryngeal nerve was observed on the right side in 31 cases (0.51%), with no anatomic anomalies found on the left side. The nerve anomaly was diagnosed preoperatively in five patients. A vocal cord deficit, caused by a nerve lesion, was observed in four cases (12.9%). Our results suggest that the best way to avoid morbidity is routine identification of the nerve. This can be done by carefully identifying all the thyroid structures and being suspicious of the presence of the abnormality when the inferior laryngeal nerve is not found in a classic position.     

Tumor Proximity to the Recurrent Laryngeal Nerve in Patients with Primary Hyperparathyroidism Undergoing Parathyroidectomy

Background

Recurrent laryngeal nerve (RLN) injury is a rare complication for patients undergoing neck exploration for primary hyperparathyroidism (pHPT). Distances between RLNs and parathyroid adenomas have not been previously published. In this study we used a RLN monitor to identify the RLN and to measure the proximity to parathyroid tumors.

Methods

Patients with pHPT (n?=?136) underwent neck exploration and had the clinical data recorded prospectively. Adenomas were recorded in 1 of 4 locations (right upper, right lower, left upper, left lower). Measurement of RLN to adenoma distances were recorded intraoperatively with the gland in situ. The RLN location was confirmed with a RLN monitor.

Results

The average RLN to adenoma distance was 0.52?±?0.52?cm. Adenomas in the right upper position were significantly closer to the nerve (0.25?±?0.39?cm) compared with adenomas in the left upper (0.48?±?0.61?cm, p?=?.03), left lower (0.70?±?0.53?cm, p?<?.001), and right lower position (1.02?±?0.56?cm, p?<?.001). Left upper adenomas were also significantly closer to the nerve compared with right lower adenomas (p?<?.001). Adenomas in the right upper position abutted the nerve more often (47?%) compared with adenomas in other positions (p?=?.001). There were no perioperative characteristics that predicted tumor abutment. There were no permanent RLN injuries.

Conclusion

In patients with sporadic pHPT, parathyroid adenomas in the right upper location have, on average, greater proximity to the RLN and are more often directly abutting compared with adenomas in other locations.     

Computer-assisted evoked electromyography with stimulating surgical instruments for recurrent/external laryngeal nerve identification and preservation in thyroid and parathyroid operation

BACKGROUND: The reported incidence of recurrent laryngeal nerve (RLN) palsy/paralysis in thyroid and parathyroid operation ranges from 2% to 13%. Injury to the external branch of the superior laryngeal nerve (EBSLN) is less clearly documented. We hypothesized that a novel evoked electromyography system using an audio warning alarm might be beneficial for detection and preservation of the RLN and EBSLN. METHODS: A total of 117 thyroid/parathyroid operations were performed using a nerve locator/monitor (Neurovision SE, RLN Systems Inc, Jefferson City, Mo). Dissection was performed using a stimulating hemostat with conduction to an endotracheal surface electrode. RESULTS: A total of 97 thyroidectomies (50 total, 47 lobectomies) and 20 parathyroidectomies (16 directed, 4 bilateral) were performed representing 176 RLN and 152 EBSLN at risk. Of 176 RLN, 161 were correctly identified by the nerve stimulator alarm including 2 nonrecurrent nerves. The cricothyroid space and the superior pole vessels were scanned to identify the EBSLN by observing for cricothyroideus contraction or an alarm. Fourteen of 152 (8.9%) cases of type 2 anatomy were suggested where meticulous dissection of superior pole vessels prevented EBSLN injury. CONCLUSIONS: Computer-assisted evoked electromyography with stimulating surgical instruments is a useful surgical tool. This technology may be especially useful in reoperation in dense scar tissue and preserving the EBSLN in thyroid operation.     

喉返神经的显露在甲状腺癌根治术中的意义

目的探讨喉返神经的显露在甲状腺癌根治性手术中的意义。方法回顾分析2003年7月至2006年12月间186例主动显露喉返神经的甲状腺癌根治手术病例资料。结果186例甲状腺癌均施行甲状腺全切或近全切除术。术中均成功显露双侧喉返神经,其中1例右侧非返喉下神经。喉返神经永久性损伤1例,暂时性损伤1例,永久损伤率为0．54％。结论甲状腺癌根治术中应常规在甲状腺下动脉周围寻找喉返神经,主动显露喉返神经不仅可减少喉返神经损伤的发生率,并可提高甲状腺癌手术的彻底性。     

Improvement of vocal cord paresis after thyroidectomy

Iatrogenic vocal cord paralysis is a well-publicized complication of thyroid and parathyroid operations. Less appreciated is the improvement of vocal cord function after resection of a thyroid or parathyroid tumor. Over the last 22 years, 14 patients presented with vocal cord paresis in the presence of thyroid or parathyroid tumors. Of these 14 patients, nine had complete resolution of paresis following resection of the thyroid or parathyroid tumors: three had a thyroid carcinoma impinging upon the nerve, three had large colloid goiters, two had a follicular adenoma and one had a parathyroid adenoma displacing the nerve. In five of the 14 patients the vocal cord paralysis persisted after operation. In three, the pathology accounted for the vocal cord paralysis and was not amenable to operative improvement: one patient had an unresectable anaplastic thyroid carcinoma, one patient had long-standing idiopathic unilateral vocal cord paralysis, and one patient had laryngeal adenoid cystic carcinoma with thyroid invasion. The fourth patient had an extensive thyroid hemangioma. The paralysis persisted after resection. The fifth patient had long-standing idiopathic vocal cord palsy. A preoperative vocal cord paresis in a patient with thyroid or parathyroid disease does not indicate permanent loss of recurrent nerve function, even in the presence of carcinoma. In this series, vocal cord function was restored in 9 of 10 patients with resectable thyroid or parathyroid tumors.     

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??Clinical study of the recurrence of the central lymph node after central lymph node dissection in papillary thyroid carcinoma SHAO Tang-lei*??ZHOU Wei,ZHAN Weiwei,et al. *Department of General Surgery, Ruijin Hospital,Shanghai Jiaotong University School of Medicine,Shanghai 200025,China
Corresponding author:YANG Wei-ping,E-mail:yangweipingmd@126.com
Abstract Objective To study the reason of the recurrence of the central lymph node after central lymph node dissection in papillary thyroid carcinoma.Methods The clinical data of 38 cases from January 2011 to December 2013 at our department were analyzed retrospectively.Results All central lymph nodes percured in the second operation were proved with metastasis by pathology in all cases.34 cases (89.7%)of all were located in former right central lymph node area,and 4 cases(10.5%) of all were located in former left central lymph node area.The recurrent central lymph node in right side was located among trachea,right recurrent laryngeal nerve and apex of lung beneath right carotid artery. The recurrent central lymph node in left side was located between trachea and left carotid artery beneath calvicle. The rate of transient vocal hoarseness and permanent recurrent laryngeal nerve injury was 18.4% and 2.6% respectively.The rate of transient hypocalcemia was 15.8%.Conclusion Because of the high injury rate of recurrent laryngeal nerve and parathyroid in the second central lymph node dissection,We suggested that the first central lymph node dissection should be performed thoroughly,especially not leaving out the area among trachea,right recurrent laryngeal nerve and apex of lung beneath the oblique right carotid artery.     

Gasless Endoscopic Thyroid and Parathyroid Surgery Using a New Retractor

Endoscopic thyroid and parathyroid surgery have now become feasible procedures, but the working space provided by the gasless technique is more limited than that of the CO₂ insufflation technique. Gasless endoscopic surgery was performed in 20 patients with thyroid or parathyroid tumors. A newly designed retractor was used. Gasless endoscopic surgery was performed in all patients without conversion to conventional techniques. The recurrent laryngeal nerve was visualized and preserved in all patients. No recurrent nerve palsy was noted. The new retractor created a sufficient working space, and our results demonstrated the feasibility of this technique. Received: November 27, 2000 / Accepted: May 15, 2001     

喉返神经喉外分支的临床意义(附13例报告)

目的：了解喉返神经喉外分支的解剖特点发病情况和术中喉返神经损伤的原因。方法：1991年至2001年共收治行甲状腺叶切除术的病人145例，术中常规解剖暴露喉返神经。结果：本组共发现喉返神经喉外分支13例，占9％。男4例，女9例，平均年龄46岁，右侧9例，左侧4例。喉返神经喉外分支分为2支者10例，占76．9％，3支者2例，1例为4个分支。喉外分支点距环甲关节入喉处的距离多在2cm以上，有的甚至低于甲状腺下动脉平面。结论：喉返神经有时常在喉外分为2或3个分支，为避免在甲状腺切除手术时损伤喉返神经，作者认为术中常规解剖暴露出喉返神经是避免其损伤的最好方法。