Incidence and spread pattern of lymph node metastasis from submandibular gland cancer.

OBJECTIVES: To clarify the indication of neck dissection (ND) for patient with submandibular gland (SMG) cancer. METHODS: A total of 43 patients with SMG cancer were retrospectively analyzed. Forty-one patients underwent ND: Levels I-V in 19 patients, Levels I-III in 18 patients, and Level Ib in 4 patients. The other two patients did not undergo ND, since preoperative diagnoses were benign. Postoperative radiotherapy was performed in 19 patients with positive surgical margin, high grade cancer or stage IV disease. RESULTS: LN metastases were pathologically confirmed in all patients with cN + and 6 out of 31 patients with cN-. No patients developed regional recurrence during follow-up periods. Ultimately, LN metastases were pathologically confirmed in 17 of 27 high grade, one out of 9 intermediate grade, but not in 7 low grade. CONCLUSIONS: Prophylactic neck dissection should be considered in T3/4 and high grade SMG cancers.

Splenic volume in pneumococcal pneumonia patients is associated with disease severity and mortality.

Splenectomy is a risk factor for serious pneumococcal disease like overwhelming post-splenectomy infection (OPSI). In healthy individuals with small spleen, fulminant pneumococcal infection similar to OPSI has been reported. Furthermore, it is reported that small spleen was associated with severe pneumococcal infection patients treated in an intensive care unit. However, the association between the small spleen and pneumococcal pneumonia was not investigated enough. We retrospectively analyzed patients with pneumococcal pneumonia who underwent computed tomography examination with measurement of the splenic volume at Harasanshin Hospital between 2004 and 2019. Data on their background characteristics, laboratory findings, and clinical courses were collected. 413 patients were included in the final analysis. The splenic volume was significantly lower in the moderate (P < 0.001), severe (P < 0.00005), and extremely severe (P < 0.001) pneumonia groups compared with the mild pneumonia group. Furthermore, the splenic volume was significantly lower in patients died within 30 days of pneumonia treatment (median of 73.49 versus 110.77 cm3, P < 0.005) or during hospitalization (median of 71.69 versus 111.01 cm3, P < 0.0005). Splenic volume <40 cm3 was significantly associated with mortality within 30 days and total hospital mortality as a risk factor in univariate analysis. Splenic volume <40 cm3 was an independent risk factor for mortality within 30 days (odds ratio: 5.0, 95% confidence interval: 1.2-21.1, P < 0.05) and total hospital mortality (odds ratio: 7.4, 95% confidence interval: 1.8-30.6, P < 0.01) in multivariate logistic regression analysis. These results suggest that small spleen is a risk factor for severity and mortality of pneumococcal pneumonia.

Salvage surgery for structural local recurrence of papillary thyroid cancer: recurrence patterns and surgical outcome.

To clarify the patterns of the recurrence and to assess the oncological and functional outcomes after salvage surgery for the patients with structural local recurrence of papillary thyroid cancer (PTC), twenty-five patients who underwent salvage surgery for structural local recurrence of PTC were retrospectively reviewed. Structural recurrences were observed in the tracheal lumen in 5 patients, intraluminal or intramuscular esophagus in 5 patients, trachea, and cricoid cartilage in 9 patients, cricoid and thyroid cartilage in 2 patients, intra-lumen of the larynx in 1 patient and soft tissue around thyroid in 3 patients, respectively. Although all local disease was resected with macroscopically negative margin, 10 patients diagnosed as microscopically positive margin. Major surgical complications occurred in 6 patients, including common carotid artery injury (n = 1), unintentional pharyngeal or esophageal injury (n = 2), recurrent laryngeal nerve paralysis (n = 2), and pharyngeal fistula resulting in common carotid artery rupture (n = 1), and were successfully managed. During the follow-up periods, 6 patients were alive without disease, 15 patients survived with distant metastases and/or locoregional recurrence, and 4 patients died of the disease. While tracheocutaneous fistula remained in 7 patients, the vocal function was preserved in all patients but one who underwent total laryngectomy. Normal oral intake was retained in all patients. In conclusion, although salvage surgery for structural recurrence of PTC has a high risk of complications, it may be worthwhile when macroscopic curative resection is available. The decision should be made considering various factors including curability, risk of surgical procedure, functional outcome, and life expectancy.

Functional and oncological outcomes after retropharyngeal node dissection for papillary thyroid carcinoma.

BACKGROUND: Papillary thyroid carcinoma frequently metastasizes to central and lateral neck lymph nodes, but metastasis to retropharyngeal lymph nodes (RPLN) is rare. PATIENTS AND METHODS: We retrospectively reviewed 16 patients with RPLN metastasis of PTC who underwent therapeutic dissection of RPLN metastases. RESULTS: Among 16 patients, 7 patients underwent RPLN dissection with initial surgery and remaining 9 patients as salvage surgery. RPLN metastasis arose unilaterally in 15 patients and bilaterally in 1 patient. Eleven patients showed temporal dysphagia and four patients showed temporal vocal cord paralysis, but both symptoms eventually recovered in all cases. Two patients with salvage RPLN dissection died of distant metastasis and six patients survived with distant metastasis and/or persistent loco-regional disease. Other eight patients have been alive without disease. CONCLUSIONS: Although transcervical approach for RPLN metastases of PTC provided acceptable functional and oncological outcomes, half of the patients with RPLN metastasis have had distant metastasis and/or persistent locoregional disease. Indications of surgery for patients with RPLN metastasis need to be performed carefully in consideration of patients' prognosis and quality of life.

Epigenetic down-regulation of SOX2 is an independent poor prognostic factor for hypopharyngeal cancers.

AIMS: We recently reported that a small subset (7%) of oesophageal squamous cell carcinomas completely lacking SOX2 expression had unique clinicopathological features and a dismal prognosis. The aim of the present study was to elucidate whether the findings obtained in oesophageal cancers are applicable to hypopharyngeal squamous cell carcinomas (HPSCCs) or oropharyngeal squamous cell carcinomas (OPSCCs). METHODS AND RESULTS: The study cohort consisted of consecutive patients with HPSCC (n = 130) and OPSCC (n = 65) who underwent surgery without preoperative therapy. On immunostaining, SOX2 was almost entirely negative in 10 of 130 HPSCCs (8%) and seven of 65 OPSCCs (11%). No significant differences were observed in clinicopathological features, including p16 status, between SOX2-positive and SOX2-negative cancers. However, patients with SOX2-negative HPSCC had significantly worse overall and recurrence-free survival than those with SOX2-positive HPSCC, whereas such a prognostic relationship was not confirmed in patients with OPSCC. In a multivariate analysis, the loss of SOX2 expression appeared to be an independent poor prognostic factor for patients with HPSCC. In a sequencing analysis, no mutation was found in SOX2. As SOX2 is known to contain an extensive CpG island before the transcription start site, methylation-specific polymerase chain reaction for the SOX2 promoter was performed. Methylated alleles were found in nine of 10 SOX2-negative HPSCCs but in none of SOX2-positive HPSCCs. CONCLUSIONS: Similarly to oesophageal cancers, a small subset (8%) of HPSCCs characteristically almost completely lacking SOX2 expression appeared to be aggressive neoplasms with high recurrence rates. Promoter hypermethylation was determined to be a major mechanism underlying epigenetic SOX2 silencing.

Solvated states of poly-L-alanine α-helix explored by Raman optical activity.

Raman optical activity (ROA) reveals surprising details of the secondary structure of polypeptides and proteins in solution phase. Yet specific spectral features, such as in the extended amide III region of hydrated α-helix, did not seem explicable by the generally accepted sensitivity of ROA to the local conformation. This is reconciled in the present study by simulations of ROA spectra for model α-helical structures. Two positive ROA peaks often observed at around 1340 and 1300 cm(-1) for polypeptides and proteins have been assigned to two types of solvated α-helices; one is stable in hydrophilic environment where amide groups make hydrogen bonds to solvent molecules or polar side chains (∼1340 cm(-1)), and the other is supported by a hydrophobic environment without the possibility of external hydrogen bonds (∼1300 cm(-1)). For poly-L-alanine (PLA), regarded as a good model of α-helical structure, the experimentally observed relative intensity ratio of the two ROA bands has been explained by a conformational equilibrium depending on the solvent polarity. The intensities of the bands reflect solvated and unsolvated α-helical geometries, with peptide backbone torsional angles (ϕi+1, ψi) of (-66°, -41°) and (-59°, -44°), respectively. Quantum-mechanical simulations of the ROA spectra utilizing the normal mode optimization and Cartesian tensor transfer methods indicate, however, that the change in dielectric constant of the solvent is the main factor for the spectral intensity change, whereas the influence of the conformational change is minor.

Induction of Immunological Antitumor Effects by the Combination of Adenovirus-Mediated Gene Transfer of B7-1 and Anti-Programmed Cell Death-1 Antibody in a Murine Squamous Cell Carcinoma Model.

BACKGROUND: The goal of this study was to evaluate the antitumor immune effects of B7-1 gene expression in addition to immune checkpoint inhibitor against squamous cell carcinoma. METHODS: A murine SCC cell line, KLN205, was infected with adenoviral vector carrying B7-1 (AdB7). Infected cells were injected subcutaneously in the flanks of DBA/2 mice. Three weeks after implantation, anti-mouse PD-1 antibody (antiPD1) was intraperitonially administrated twice a week for a total of six times. RESULTS: CD80 was significantly overexpressed in the AdB7-infected tumors. IFN-gamma in the T cells in the spleen was significantly increased and tumor size was significantly reduced in the mice treated with both AdB7 and antiPD1. Targeted tumors treated with both AdB7 and antiPD1 exhibited significantly increased cell densities of total immune cells as well as Ki-67+ CD8+ T cells and decreased regulatory T cells. CONCLUSIONS: These results suggest that the B7-1 gene transfer may enhance the antitumor effect of anti-PD1 antibody against SCC.

A Case of Olfactory Neuroblastoma Developing Bilateral Retropharyngeal Lymph Node Metastasis 14-years After Skull Base Surgery.

Olfactory neuroblastoma (ONB) is an uncommon malignant tumor and is usually treated by a multidisciplinary approach includes surgery, radiotherapy, and chemotherapy. A 62 years-old male had a tumor in the nasal cavity and diagnosed as ONB with Kadish A stage. Anterior skull base surgery was performed as radical treatment. Since the surgical margin was negative, no postoperative radiotherapy was administered. 14 years after the surgery, bilateral otitis media with effusion (OME) was occurred, we found the recurrence tumor at bilateral retropharyngeal lymph node (RPLN) which surrounded the internal carotid arteries. Since these were unresectable, we planned chemoradiotherapy which was 70Gy of intensity modulated radiotherapy combined with two courses of carboplatin and etoposide. The tumor volume was reduced and bilateral OME were improved. He has been alive for 3 years after salvage treatment. Although ONB has a relatively good prognosis, it is known to often cause cervical lymph node metastasis. Grades III and IV of Hyams classification are considered high risk. This case, initial tumor was limited in the nasal cavity and its clinical classification was early stage, but Hyams classification was grade III. In reference to this case, considering that RPLN metastasis are difficult to radically resect at the salvage surgery, including this area in postoperative radiotherapy was considered an option.

Oncological Outcomes of Concurrent Chemoradiotherapy and Surgical Treatment for Patients With T3 Hypopharyngeal Cancer: A Single-Center Retrospective Analysis.

Background Since the larynx and pharynx are vital for respiration, swallowing, and speech, chemoradiotherapy (CRT) has been widely applied for T3 hypopharyngeal cancer (HPC) as an organ-preserving treatment. However, CRT can lead to severe late adverse events such as dysphagia and aspiration pneumonia, especially in patients who have difficulty swallowing and/or aspiration at the time of initial diagnosis. Patients and methods Between 2012 and 2020, 86 patients with T3 HPC treated with curative intent at Kobe University Hospital were included in this study. The average age was 69 years old, ranging from 43 to 89. Diseases were classified as Stage III in 29 patients, Stage IVA in 52 patients, and Stage IVB in five patients. Thirty-five (41%) patients were treated by CRT, and 51 (59%) patients were treated by surgery. Patients were followed up for at least two years, and the follow-up period ranged from four to 128 months (median: 45 months). Results Three-year progression-free survival (PFS) rates of patients treated by CRT and patients treated by surgery were 56.2% and 60.3%, respectively. Three-year disease-specific survival (DSS) rates of patients treated by CRT and surgically treated patients were 79.0% vs. 70.8%, respectively. Three-year overall survival (OS) rates of patients treated by CRT and surgically treated patients were 64.5% and 69.0%, respectively. Of note, a significant difference was observed between three-year DSS and three-year PFS (79.0% vs. 56.2%, p = 0.0014) in the patients treated by CRT but not in the patients treated by surgery. Conclusions No significant differences were observed between the PFS, DSS, and OS rates of patients treated by CRT and those of surgically treated patients. Locoregional recurrences after CRT were significantly successfully salvaged by surgical intervention. These results suggest that CRT can be applied as an alternative to surgery without reducing survival, especially for patients without severe clinical symptoms. Meticulous follow-up is mandatory for early detection of recurrence to salvage by surgery and for the management of late adverse events.

Targeting Anterior Commissure Involvement with Hyperfractionated Radiotherapy for T1-T2 Squamous Cell Carcinoma of the Glottic Larynx.

Anterior commissure is involved in about 20% of early-stage glottic squamous cell carcinomas (EGSCCs). Treatment outcomes and prognostic factors for EGSCC with anterior commissure involvement (ACI) were evaluated by focusing on hyperfractionated radiotherapy (74.4 Gy in 62 fractions). One-hundred and fifty-three patients with T1-T2 EGSCC were included in this study. The median total doses for T1a, T1b, and T2 were 66, 74.4, and 74.4 Gy, respectively. Overall, 49 (32%) patients had T1a, 38 (25%) had T1b, and 66 (43%) had T2 disease. The median treatment duration was 46 days. The median follow-up duration was 5.1 years. The 10-year overall and cause-specific survival rates were 72% and 97%, respectively. The 10-year local control rates were 94% for T1a, 88% for T1b, and 81% for T2 disease. Local control rates in patients with ACI were slightly better than those in patients without ACI with T1a and T1b diseases; however, the difference was not significant. The 10-year laryngeal preservation rate was 96%. Six patients experienced grade 3 mucositis, and four patients had grade 3 dermatitis. Hyperfractionated radiotherapy was effective for T1 disease with ACI, but insufficient for T2 disease with ACI. Our treatment strategy resulted in excellent laryngeal preservation.

Expressions of NeuroD and GAP43 as diagnostic markers for olfactory neuroblastoma.

OBJECTIVE: Olfactory neuroblastoma (ONB) is often difficult to pathologically distinguish from other small round cell tumors (SRCTs) arising in the nasal cavities. Although there are several diagnostic markers used for differential diagnosis of ONB, these molecules are also expressed in various neuronal derived tumors. Here, we examined the expression of NeuroD, GAP43, and olfactory marker protein (OMP) in ONB and non-ONB SRCT to determine their utility in the differential diagnosis of ONB. METHODS: Twenty-six patients diagnosed with and treated for ONB at Kobe University Hospital between 1997 and 2017 with formalin-fixed, paraffin-embedded biopsy or surgical resection specimens were included. The expressions of NeuroD, GAP43, and OMP were immunohistochemically examined in these 26 ONB specimens and specimens from 13 SRCTs arising in the nasal cavities for reference. RESULTS: Among the 26 ONB samples, focal, patchy, and marked staining for NeuroD was observed in 4, 3, and 9 samples, respectively. Focal, patchy, and marked GAP43 staining was observed in 5, 3, and 11 samples, respectively. Consequently, marked positive staining for either NeuroD or GAP43 was observed in 54% (14/26) of ONBs. Among the 13 SRCTs, marked staining for NeuroD was observed in two small cell carcinomas, one undifferentiated carcinoma, and one neuroendocrine carcinoma, whereas marked positive staining for GAP43 was observed only in one undifferentiated carcinoma. No specimen in this study exhibited OMP staining. CONCLUSIONS: Our results suggest possible roles of GAP43 immunostaining in the differential diagnosis of ONB.

OK432 sclerotherapy for refractory chylous leakage after neck dissection.

Chylous leakage is a rare but serious postoperative complication of neck dissection (ND). Most chylous leakages are successfully treated either by drainage or ligation of the thoracic duct, but the resolution is occasionally prolonged. OK432 sclerotherapy is used to treat various refractory cystic diseases of the head and neck. Three patients were treated with OK432 sclerotherapy for refractory chylous leakage following ND. Case 1 involved a 77-year-old man with chylous leakage after a total laryngectomy and bilateral ND. Case 2 involved a 71-year-old woman who underwent total thyroidectomy and left ND for thyroid cancer. Case 3 involved a 61-year-old woman who underwent right ND for oropharyngeal cancer. In all patients, chylous leakage rapidly improved after OK432 injection without any complications. Our results suggest the efficacy of OK432 sclerotherapy in patients with refractory chylous leakage after ND.

Influences of Orogastric and Nasogastric Tubes on Sucking Pressure during Bottle Feeding in Immature Infants.

Orogastric (OG) and nasogastric (NG) tubes have been reported to delay breastfeeding initiation and affect respiratory function. However, the effects of feeding tubes on sucking pressure have not been well studied. Fourteen preterm infants were enrolled in this study, and their sucking pressures during bottle feeding with an OG tube, NG tube, and without any tube were measured. Sucking pressure significantly increased after changing the OG tube to an NG tube (p = 0.044). However, sucking pressure showed no significant differences after changing the feeding method from an NG tube to oral intake. Thus, NG tubes are superior to OG tubes in terms of sucking pressure.

Corrigendum: Influences of Orogastric and Nasogastric Tubes on Sucking Pressure during Bottle Feeding in Immature Infants.

This corrects the article in Kobe J Med Sci. 2023 May 31; 69(1): E25-E32.

Salvage surgery for mesenteric lymph node metastasis by resection of the first jejunal flap and reconstruction with the second jejunal flap.

We report a case of a second free jejunal transfer to treat metastasis in the mesenteric lymph node of the first jejunal flap. A 73-year-old man underwent total pharyngolaryngectomy, bilateral neck dissection, and free jejunal transfer for recurrent hypopharyngeal cancer [left pyriform sinus, pT2N0, moderately differentiated squamous cell carcinoma (SCC)] after radiotherapy. Seven years post-surgery, he underwent transoral videolaryngoscopic surgery for oropharyngeal cancer (soft palate, pT1N0, well-differentiated SCC). Ten years after the first jejunal transfer, metastasis was found in the mesenteric lymph node surrounding the jejunal flap's vascular pedicle. Under general anesthesia, resection of the first jejunum including the affected lymph node, and second jejunal transfer were performed. Lymph node pathological examination revealed poorly differentiated SCC, compatible with pharyngeal cancer metastasis. After neck dissection and jejunal flap transfer, lymphatic collateral pathways toward the flap's mesenteric lymph node might form. Possibly, hypopharyngeal or oropharyngeal cancer metastasized via this pathway.

Oncological outcomes of concurrent chemoradiotherapy with docetaxel, cisplatin, and 5-fluorouracil for locally advanced squamous cell carcinoma of the external auditory canal: A single-center study.

BACKGROUND: Squamous cell carcinoma of the external auditory canal (EACSCC) is a rare condition. However, a standard treatment has not yet been established. We retrospectively evaluated the efficacy, adverse events, and feasibility of TPF-CCRT (concomitant chemoradiotherapy with docetaxel, cisplatin, and 5-fluorouracil) in patients with advanced EACSCC. METHODS: Thirty-five consecutive patients with advanced EACSCC (T3, T4) initially treated with TPF-CCRT at Kobe University Hospital were included. T4 diseases with invasion of the brain, internal carotid artery, or internal jugular vein were classified as T4b, and those without these features were classified as T4a. RESULTS: Five-year overall survival rates for T3 and T4 were 100% and 64.2%, respectively. A significant difference was observed between T4a and T4b (82.4% vs. 30%, p = 0.007). Five-year progression-free survival rates of T3, T4a, and T4b were 100%, 68%, and 20% (p = 0.022), respectively. CONCLUSIONS: TPF-CCRT should be considered as a plausible treatment option for advanced EACSCC.

Efficacy of a High-definition Three-dimensional Exoscope in Simultaneous Transcranial and Endoscopic Endonasal Surgery: A Case Report.

Owing to recent advances in medical optical technology, a high-definition (4K) three-dimensional (3D) exoscope has been developed as an alternative tool to using conventional microscopes for microscopic surgery, and its efficacy for neurosurgery has been reported. We report a case who underwent simultaneous surgery aiming for en bloc resection of an anterior skull base malignancy with concurrent exoscopic transcranial and endoscopic endonasal approaches using a 4K 3D exoscope. The patient was a 76-year-old woman who underwent en bloc resection for an anterior skull base olfactory neuroblastoma 13 years ago. After confirming the recurrence of progressive olfactory neuroblastoma, tumor resection was again decided to be performed. As with the first procedure, surgery was performed in an en bloc manner, using both transcranial and endonasal approaches. Exoscope provided enough space above the surgical field to allow us to perform transcranial and endonasal surgeries simultaneously. Moreover, the surgeons could maintain a comfortable posture throughout the procedure, and total tumor removal was successfully achieved without any abnormal event. To our knowledge, this is the first report of the introduction of an exoscope aiming for en bloc resection of an anterior skull base malignancy while performing simultaneous surgery with both transcranial and endonasal approaches. We believe that the more cases are accumulated, the more efficacy of a 4K 3D exoscope will be elucidated.

Blowing time ratio and high-resolution manometry to evaluate swallowing function of patients with oral and oropharyngeal cancer.

OBJECTIVE: The blowing time ratio, which is the ratio of the blowing time when the nostrils are open and closed, is significantly correlated with velopharyngeal pressure, not only during speech but also during swallowing. This study aimed to further evaluate the usefulness of the blowing time ratio as a screening tool to evaluate the swallowing pressure of patients treated for oral and oropharyngeal cancers using high-resolution manometery (HRM). METHODS: Ten patients treated for oral or oropharyngeal cancer were recruited for this study. Swallowing pressures at the velopharynx, oropharynx, and upper esophageal sphincter (UES) were measured using HRM. Their correlations with the blowing time ratio were analyzed. RESULTS: The blowing time ratio was significantly correlated with the swallowing pressures of the oropharynx (CC = 0.815, p = 0.004) and the velopharynx (CC = 0.657, p = 0.039), but not of the UES. CONCLUSIONS: The present results further support our previous finding that the blowing time ratio is a useful screening tool to evaluate velopharyngeal and oropharyngeal swallowing pressures in patients treated for oral and oropharyngeal cancer.

The prospective evaluation and risk factors of dysphagia after surgery in patients with oral cancer.

BACKGROUND: This prospective study investigated the change of swallowing ability using the Swallowing Ability Scale System (SASS) and swallowing-related quality of life (QOL) by Performance Status Scale for Head and Neck Cancer patients (PSS-H&N). This study also investigated the risk factors for postoperative dysphagia in patients who received reconstructive surgery for oral cancer. SUBJECTS AND METHODS: This study included 64 patients (33 men and 31 women) who underwent radical surgery with neck dissection and reconstructive surgery for oral cancers between July 2014 and February 2018. We evaluated risk factors for poor swallowing ability after treatment, including demographic factors, preoperative factors and perioperative factors, with univariate and multivariate analyses. The change of swallowing ability by the SASS and swallowing-related QOL by PSS-H&N were evaluated prospectively prior to the initiation of surgery within 1 week and at 1 and 3 months after treatment. RESULTS: Advanced T stage (T3, 4) (odds ratio (OR) = 79.71), bilateral neck dissection (OR = 20.66) and the resection of unilateral or bilateral suprahyoid muscles (OR = 17.00) were associated with poor swallowing ability after treatment. The scores for time for food intake and Eating in Public were associated with decrease of QOL in the poor group. CONCLUSIONS: We propose that clinicians consider the risk factors identified in this study and pay close attention to the management of oral cancer patients with reconstructive surgery.

Left non-recurrent inferior laryngeal nerve in a patient with right-sided aortic arch and aberrant left subclavian artery.

Non-recurrent inferior laryngeal nerve (NRILN) is rare but one of the important anatomical variations in thyroid and parathyroid surgery. Almost all cases were observed on the right side with aberrant right subclavian artery and left NRILN have been reported in only five cases so far. Here, we reported a 38 year-old Japanese male with left NRILN accompanying adenomatous goiter. He was referred to our hospital for the surgical treatment of left thyroid goiter. Preoperative computed tomography revealed right-sided aortic arch and aberrant left subclavian artery with no signs of complete situs inversus viscerum, suggesting possible left NRLN. Left hemithyroidectomy was performed using nerve monitoring system. Intraoperatively, left recurrent laryngeal nerve was not identified along tracheoesophageal groove, but directly originated from vagal nerve and was running horizontally to larynx. Mobility of vocal cords were not impaired and postoperative course was uneventful. During thyroid surgery for the patients with right-sided aortic arch, meticulous care should be taken using nerve monitoring system to avoid nerve injury.