Potential value of CT-based comprehensive nomogram in predicting occult lymph node metastasis of esophageal squamous cell paralaryngeal nerves: a two-center study.

PURPOSE: The aim of this study is to construct a combined model that integrates radiomics, clinical risk factors and machine learning algorithms to predict para-laryngeal lymph node metastasis in esophageal squamous cell carcinoma. METHODS: A retrospective study included 361 patients with esophageal squamous cell carcinoma from 2 centers. Radiomics features were extracted from the computed tomography scans. Logistic regression, k nearest neighbor, multilayer perceptron, light Gradient Boosting Machine, support vector machine, random forest algorithms were used to construct radiomics models. The receiver operating characteristic curve and The Hosmer-Lemeshow test were employed to select the better-performing model. Clinical risk factors were identified through univariate logistic regression analysis and multivariate logistic regression analysis and utilized to develop a clinical model. A combined model was then created by merging radiomics and clinical risk factors. The performance of the models was evaluated using ROC curve analysis, and the clinical value of the models was assessed using decision curve analysis. RESULTS: A total of 1024 radiomics features were extracted. Among the radiomics models, the KNN model demonstrated the optimal diagnostic capabilities and accuracy, with an area under the curve (AUC) of 0.84 in the training cohort and 0.62 in the internal test cohort. Furthermore, the combined model exhibited an AUC of 0.97 in the training cohort and 0.86 in the internal test cohort. CONCLUSION: A clinical-radiomics integrated nomogram can predict occult para-laryngeal lymph node metastasis in esophageal squamous cell carcinoma and provide guidance for personalized treatment.

Electrode fabrication and interface optimization for imaging of evoked peripheral nervous system activity with electrical impedance tomography (EIT).

OBJECTIVE: Non-invasive imaging techniques are undoubtedly the ideal methods for continuous monitoring of neural activity. One such method, fast neural electrical impedance tomography (EIT) has been developed over the past decade in order to image neural action potentials with non-penetrating electrode arrays. APPROACH: The goal of this study is two-fold. First, we present a detailed fabrication method for silicone-based multiple electrode arrays which can be used for epicortical or neural cuff applications. Secondly, we optimize electrode material coatings in order to achieve the best accuracy in EIT reconstructions. MAIN RESULTS: The testing of nanostructured electrode interface materials consisting of platinum, iridium oxide, and PEDOT:pTS in saline tank experiments demonstrated that the PEDOT:pTS coating used in this study leads to more accurate reconstruction dimensions along with reduced phase separation between recording channels. The PEDOT:pTS electrodes were then used in vivo to successfully image and localize the evoked activity of the recurrent laryngeal fascicle from within the cervical vagus nerve. SIGNIFICANCE: These results alongside the simple fabrication method presented here position EIT as an effective method to image neural activity.

Diagnosis, anatomy, and electromyography profiles of 73 nonrecurrent laryngeal nerves.

BACKGROUND: The purpose of this work was to compare methods of detecting nonrecurrent laryngeal nerves (NRLNs). METHODS: Specificity and sensitivity were compared in three NRLN detection methods: CT, electromyography (EMG), and A-B point comparison. RESULTS: A total of 73 intraoperative pictures and 36 CT details of NRLNs are presented. Incidence of NRLN was 0.39%. Type I NRLN accounted for 50.7%, type IIA 45.2%, type IIB 4.1%. The NRLN median latency was 2.13 ms vs 3.00 ms median in an RLN control group (P < .001). When the threshold was set to 2.5 ms, EMG latency detection had 96.7% sensitivity and 91.6% specificity for detecting NRLN, and the A-B point comparison algrithm had 97.3% sensitivity and 92.5% specificity. Combining EMG latency detection with A-B point comparison achieved 100% sensitivity and specificity for detecting NRLN. CONCLUSION: This is the largest series of NRLN presented in the literature. Latency shorter than 2.50 ms combined with the A-B point comparison method is the ideal algorithm procedure for early NRLN identification.

Gamma Knife Radiosurgery of the Superior Laryngeal Neuralgia: A Report of 3 Cases.

BACKGROUND: Superior laryngeal neuralgia (SLN) is a relatively rare disorder that is characterized by neck pain. There are only a few reported cases and treatment options for SLN to date. In this study, we report 3 patients with SLN who were treated with Gamma Knife radiosurgery (GKRS) at the time of diagnosis. CASE DESCRIPTION: For all 3 patients, GKRS was administered using a 4-mm collimator to deliver a single shot of 80 Gy of radiation (100% isodose line). The target was set at the jugular foramen where the vagus and glossopharyngeal nerves emerge from the skull. Follow-up assessments were performed at 32, 31, and 30 months after GKRS. The 3 patients described pain relief at 3 months, 2 days, and 6 weeks. None of the patients developed neurologic deficits during the follow-up period. CONCLUSIONS: This preliminary report provides encouraging evidence that GKRS represents an effective, safe, and relatively durable noninvasive treatment option for patients with SLN.

Anatomic Characteristics, Identification, and Protection of the Nonrecurrent Laryngeal Nerve during Thyroidectomy.

Objective We aimed to investigate the anatomical features and variation pattern of the nonrecurrent laryngeal nerve (NRLN), summarize the methods for identifying the NRLN before and during thyroidectomy, and share experiences regarding preventing and treating its injury. Study Design Retrospective case data analysis. Setting First Affiliated Hospital of Harbin Medical University. Subjects and Methods Between January 2002 and May 2016, 7392 patients underwent thyroidectomy in our hospital. Of them, 28 patients with NRLN were identified, and their clinical data were retrospectively analyzed. Results This study included 7392 patients in which the recurrent laryngeal nerves (RLNs) were routinely identified during surgery. The presence of NRLN was intraoperatively confirmed in 28 patients. All the NRLNs were located on the right side and its overall incidence was 0.37%. Five of the NRLNs were classified as type I, 19 as type IIa, and 4 as type IIb. Of the 28 cases, 4 NRLNs were injured during surgery, in which primary end-to-end anastomosis or local seal with corticosteroid injection was performed as a remedy. In the 4 patients with NRLN injury, 2 presented with postoperative hoarseness that indicated vocal cord paralysis confirmed by laryngoscope; the other 2 patients' voices had no significant changes. Conclusion The NRLN, which is rare in clinical practice and predominantly right-sided, is anatomically more complex and variant at a higher risk of surgical injury. The key factors to accurately identify NRLN and to effectively prevent its injury include careful interpretation of auxiliary examination results before surgery, raising awareness of its presence, meticulous dissection, and routine exposure of the RLN during surgery.

Disease Characteristics and Electromyographic Findings of Nonsurgery-Related Unilateral Vocal Fold Paralysis.

OBJECTIVE: The detailed characteristics and prognosis of nonsurgery-related unilateral vocal fold paralysis (NSUVFP) are currently unclear. This study evaluated the extent of laryngeal nerve lesions and the individual characteristics for patients with NSUVFP. STUDY DESIGN: Retrospective, case series. METHODS: Patients with unilateral vocal fold paralysis (UVFP) were evaluated using videolaryngostroboscopy and quantitative laryngeal electromyography. The side of nerve lesions, involvement of the external branch of the superior laryngeal nerve (eSLN), and complete vocal fold motion recovery were evaluated after ≥ 6 month follow-up. RESULTS: A total of 207 UVFP patients were recruited, including 153 surgery-related UVFP and 54 NSUVFP patients. Thirty-four (63%) and 20 (37%) NSUVFP patients were further assigned to idiopathic and nonsurgery-related-nonidiopathic (NSNI) groups, respectively. In the idiopathic group, eSLN lesions occurred in all six (100%) patients with right-side paralysis, but in only six of 28 (21%) patients with left-side paralysis (P < 0.001). The turn frequency of the paralyzed thyroarytenoid-lateral cricoarytenoid muscle complex is lower in the NSNI group (333.1 ± 192.1) compared with the idiopathic group (490.2 ± 255.1) (P = 0.02). The probability of complete vocal fold motion recovery did not differ among groups (P > 0.05). CONCLUSION: Idiopathic and NSNI UVFP have different clinical presentations defined by laryngeal electromyography. NSNI UVFP had more severe denervation changes compared with idiopathic UVFP. These results may support two pathogenic mechanisms for idiopathic UVFP: 1) neuropathy specifically involving left recurrent laryngeal nerve (RLN), and 2) neuropathy affecting nerves proximal to the RLN. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1381-1387, 2017.

An update on the status of nerve monitoring for thyroid/parathyroid surgery.

PURPOSE OF REVIEW: Recurrent laryngeal nerve (RLN) injury is one of the most common and serious complications associated with thyroid and parathyroid surgery. Although routine visual identification of the RLN is considered the current standard of care, the role of intraoperative neuromonitoring (IONM) of the RLN is more controversial. RECENT FINDINGS: Despite initial enthusiasm that IONM might substantially reduce the rate of RLN injury, most studies failed to show a significant difference in the rate of RLN injury when the use of IONM was compared with visualization of the RLN alone. However, a small number of investigators have reported statistically significant differences in the rates of nerve injury when IONM is used to augment visualization alone, particularly in certain high-risk situations. Despite a lack of conclusive data showing benefit, the use of IONM as an adjunct to visual identification of the RLN has gained increasing acceptance among surgeons. IONM remains an excellent tool to help verify the identity of the RLN, confirm its functional integrity, and pinpoint the site of nerve injury in the event of dysfunction. SUMMARY: The utility of IONM in reducing the rate of RLN injury is largely unproven and remains controversial. However, the use of IONM may be helpful in certain high-risk cases. Promising new technology, such as vagal nerve monitoring, may allow more real-time monitoring of the functional integrity of the RLN and allow the surgeon to react in a timely manner to evolving dysfunction in order to abort maneuvers that may risk definitive injury.

UPPER AIRWAY BLOCKS FOR AWAKE DIFFICULT AIRWAY MANAGEMENT.

Airway anesthesia is pivotal for successful awake intubation provided either topically or by blocks. Airway blocks are considered technically more difficult to perform and carry a higher risk of complications. However, in experienced hands, they can be useful as they provide excellent intubating conditions. For complete upper airway anesthesia, bilateral glossopharyngeal and superior laryngeal nerve blocks with translaryngeal injection are required. Superior laryngeal nerve block and translaryngeal injection can be performed easily, safely and with a high success rate in patients with normal anatomy. In those with difficult landmarks, ultrasound can be of assistance. For the superior laryngeal nerve block, other targets than the nerve itself must be established to make the technique consistently successful, easy to teach, learn and perform. The same applies to the translaryngeal injection, where the use of ultrasound is necessary for correct midline identification. Intraoral glossopharyngeal nerve block is also safe and easy to perform, but associated with long lasting discomfort. Bilateral extraoral peristyloid approach should be discouraged since inadvertent blocks of the closely adjacent vagus nerve cannot be prevented in this location. A safe and easy method of blocking the distal portions of the glossopharyngeal nerve for awake intubation is therefore required.

A New Method for Automated Identification and Morphometry of Myelinated Fibers Through Light Microscopy Image Analysis.

Nerve morphometry is known to produce relevant information for the evaluation of several phenomena, such as nerve repair, regeneration, implant, transplant, aging, and different human neuropathies. Manual morphometry is laborious, tedious, time consuming, and subject to many sources of error. Therefore, in this paper, we propose a new method for the automated morphometry of myelinated fibers in cross-section light microscopy images. Images from the recurrent laryngeal nerve of adult rats and the vestibulocochlear nerve of adult guinea pigs were used herein. The proposed pipeline for fiber segmentation is based on the techniques of competitive clustering and concavity analysis. The evaluation of the proposed method for segmentation of images was done by comparing the automatic segmentation with the manual segmentation. To further evaluate the proposed method considering morphometric features extracted from the segmented images, the distributions of these features were tested for statistical significant difference. The method achieved a high overall sensitivity and very low false-positive rates per image. We detect no statistical difference between the distribution of the features extracted from the manual and the pipeline segmentations. The method presented a good overall performance, showing widespread potential in experimental and clinical settings allowing large-scale image analysis and, thus, leading to more reliable results.

Sonographically guided superior laryngeal nerve block during awake fiberoptic intubation.

We report 5 patients who underwent ultrasound-guided superior laryngeal nerve block before awake intubation and general anesthesia. We used a 8- to 15-MHz hockey stick-shaped ultrasound transducer (HST15-8/20 linear probe, Ultrasonix) to visualize the superior laryngeal nerve. A 3.8-cm 25-G needle was inserted in real time and directed toward the superior laryngeal nerve followed by circumferential placement of local anesthetic. All 5 patients tolerated subsequent awake fiberoptic intubation with either minimal or no sedation. Sonographically guided superior laryngeal nerve block may be useful in patients where identification of landmarks in the neck is difficult as a result of patient anatomy.

Increased prediction of right nonrecurrent laryngeal nerve in thyroid surgery using preoperative computed tomography with intraoperative neuromonitoring identification.

BACKGROUND: A nonrecurrent laryngeal nerve (NRLN) is a rare but potentially serious anatomical variant. Although the incidence is reported to be 0.3% to 1.3%, it carries a much higher risk of palsy during thyroid surgery. The objective of this study is to investigate the usefulness of computed tomography (CT) for preoperative identification and intraoperative neuromonitoring identification (IONM) of NRLN in thyroid cancer patients. METHODS: The preoperative neck CT scans from 1,574 patients who needed thyroid surgery were examined. Absence of the brachiocephalic artery (BCA) and the presence of arteria lusoria were defined as positive with NRLN. Systematic intraoperative neuromonitoring (IONM) was also carried out for these 1,574 patients to localize and identify NRLN. A negative electromyography (EMG) response from lower vagal stimulation but a positive EMG response from the upper position indicated the occurrence of an NRLN. RESULTS: Nine NRLN (0.57%) were intraoperatively identified out of the 1,574 patients, and no patient with a NRLN showed preoperative clinical symptoms related to NRLN. Prior to the operation, surgeons identified only seven suspected NRLN cases based on identification of arteria lusoria. But a review of CT scans revealed that all cases could be identified by vascular anomalies. All patients were successfully detected at an early stage of operation using intraoperative neuromonitoring (IONM). Postoperative vocal cord function was normal in all patients. CONCLUSIONS: CT of the neck is a reliable method for predicting NRLN before thyroid cancer surgery. However, some image features can be easily missed. Neurophysiology helps the surgeon to identify the NRLNs more precisely. Combining the two evaluation methods may decrease the incidence of nerve palsy, especially in cases of NRLN. Considering that CT is expensive, requires an X-ray, and achieves less information than ultrasound (US) concerning thyroid nodules, we suggest that applying US and IONM is more reasonable.

Prediction of nonrecurrent laryngeal nerve before thyroid surgery--experience with 1825 cases.

BACKGROUND: Nonrecurrent laryngeal nerve (NRLN) is a rare anatomic anomaly, which often co-occurs with aberrant right subclavian artery (ARSA). With this large case series, we present our experience of predicting the presence of NRLN by the means of chest X-ray film, thoracic computed tomography (CT), and ultrasonography. MATERIALS AND METHODS: A prospective, nonrandomized study has been carried out. A total of 1825 patients with various thyroid disorders scheduled for surgery were recruited between January 2006 and July 2012. All patients underwent preoperative chest X-ray examination. Those suspected with ARSA further underwent thoracic CT scan. Unsuspected patients who had NRLN revealed by surgery were analyzed with ultrasonography postoperatively. RESULTS: A total of 41 patients (2.25%) were suspected to have ARSA by X-ray, of those 19 (46.3%) were confirmed by thoracic CT and proven to have NRLN upon subsequent surgery. No NRLN injury was inflicted. For the remaining 22 cases, CT scan suggested a normal right subclavian artery and none had NRLN upon surgery. For the 1784 unsuspected patients, 4 (0.22%) were discovered to have NRLN upon surgery, of those one was injured. For the 19 predicted NRLN, the time used for identifying the nerve was significantly shorter than the four cases with unsuspected NRLN (t = -15.978; P = 0.000). After the operation, all these unsuspected NRLN were confirmed to have ARSA by ultrasonography. CONCLUSIONS: Patients scheduled for thyroid surgery should be screened for ARSA upon routine chest X-ray and thyroid ultrasonography before surgery. Detection of ARSA can accurately predict the existence of NRLN; hence prevent NRLN injury during subsequent surgery.

Non-recurrent inferior laryngeal nerve identification during robotic thyroidectomy.

OBJECTIVE: A non-recurrent inferior laryngeal nerve is a rare anomaly in which the nerve enters the larynx directly off the cervical vagus nerve, without descending to the thoracic level. It is very susceptible to damage during surgery. This report describes the important pre-operative radiological evaluations and surgical landmarks in a case of a non-recurrent inferior laryngeal nerve, identified during the recently developed technique of robotic thyroidectomy. CASE REPORT: A 38-year-old woman presented with suspected papillary microcarcinoma, as indicated by aspiration cytology. Pre-operative computed tomography showed a right aberrant subclavian artery that indicated a possible right non-recurrent inferior laryngeal nerve. Using robotic thyroidectomy methods, it was possible to carefully dissect along the thyroid capsule. The laryngeal entrance point of the right non-recurrent inferior laryngeal nerve (a constant anatomical landmark) was successfully identified via the three-dimensional, high-magnification views provided by the robotic endoscope. CONCLUSION: With proper knowledge of radiological and surgical anatomy, and the benefits of high-magnification endoscopic views, a non-recurrent inferior laryngeal nerve can be safely preserved during robotic surgery.

Ortner syndrome with recurrent pericardial effusion: a diagnostic and therapeutic dilemma.

Ortner syndrome is a rare condition characterized by hoarseness of voice in association with a cardiovascular disease. It is caused by compression of the left recurrent laryngeal nerve by the pulmonary artery or left atrium. Mitral stenosis is a well-recognized cause, however, a number of cardiac and non-cardiac conditions have also been described. Prognosis of Ortner syndrome depends on the underlying aetiology as well as the duration of illness. The case presented here describes a 35-year-old man with hoarseness of voice with recurrent pericardial effusion. Initially, a microbiologically proven diagnosis of tuberculous aetiology with resistance to Rifampicin was made; lack of optimum response and recurrence of pericardial effusion lead to subsequent diagnosis of metastatic adenocarcinoma. The patient responded to some extent to systemic and intrapericardial chemotherapy. Immunocompromised state associated with malignancy may predispose to infection including tuberculosis.

The effect of unilateral superior laryngeal nerve lesion on swallowing threshold volume.

OBJECTIVES/HYPOTHESIS: The superior laryngeal nerve (SLN) is the major sensory nerve for the upper larynx. Damage to this nerve impacts successful swallowing. The first aim of the study was to assess the effect of unilateral SLN lesion on the threshold volume sufficient to elicit swallowing in an intact pig model; this volume was defined radiographically as the maximum bolus area visible in lateral view. The second aim was to determine if a difference existed between ipsilateral and contralateral function as a result of unilateral sensory loss, measured as the radiologic density of fluid seen in the valleculae. Finally, we determined whether there was a relationship between the threshold volume and the occurrence of aspiration after a unilateral SLN lesion. STUDY DESIGN: Repeated measures animal study. METHODS: Four female infant pigs underwent unilateral SLN lesion surgery. The maximum vallecular bolus area in lateral view and the relative vallecular density on each side in the dorsoventral view were obtained from videofluoroscopic recordings in both the prelesion control and postlesion experimental states. RESULTS: In lateral view, the lesioned group had a larger maximum bolus area than the control group (P < .001). Although occasional left-right asymmetry in the dorsoventral view was observed, the vallecular densities were, on average, equal on both the left (intact) and right (lesioned) sides (P > .05). A bigger maximum bolus area did not predict aspiration in the lesioned group (P > .05). CONCLUSIONS: Unilateral SLN lesions increased the swallowing threshold volume symmetrically in right and left valleculae, but the increased threshold may not be the main mechanism for the occurrence of aspiration.

Vocal training mitigates age-related changes within the vocal mechanism in old rats.

Aging affects voice production and is associated with reduced communicative ability and quality of life. Voice therapy is a critical component of treatment, but its effects on neuromuscular mechanisms are unknown. The ultrasonic vocalizations (USVs) of rats can be used to test the effects of aging and voice use on the laryngeal neuromuscular system. This study tested the hypothesis that age-related changes in the USVs of rats and laryngeal neuromuscular junctions can be reversed through vocal exercise. Young and old rats were trained for 8 weeks to increase their USVs and were compared with a no intervention group pre- and post-treatment. USV acoustics and aspects of neuromuscular junction (NMJ) morphology were measured in the thyroarytenoid muscle. Vocal training reduced or eliminated some age differences found in both USVs and NMJs. We conclude that vocal exercise may assist in mitigating age-related changes in voice characteristics and underlying neuromuscular adaptations.

The usefulness of preoperative computed tomography and intraoperative neuromonitoring identification of the nonrecurrent inferior laryngeal nerve.

The objective of this study was to avoid the nonrecurrent inferior laryngeal nerve (NRLN) injury during surgery, we performed preoperative CT examinations to determine the variation in abnormal course of the right subclavian artery as an indictor of the presence of the NRLN and used intraoperative neuromonitoring (IONM) to identify nerve. Preoperative thyroid CT examinations were performed in 783 thyroid surgery patients. The imaging characteristics that suggested the presence of the NRLN were the following: (1) the arteria lusoria arising from the dorsal side of the aortic arch and passing through the trachea and esophagus posteriorly, and the CT image showing the characteristic "hook-like" morphology; (2) that the arteria lusoria imaging could be observed posteriorly to the trachea and esophagus; and (3) that the arteria lusoria traveled transversely from the rear of the right common carotid artery to the right subaxillary region. IONM has been applied to localize and identify NRLN. The brachiocephalic trunk was shown in 779 cases and not in the remaining four cases (0.5 %, 4/783), and these four were assumed to have the arteria lusoria. The separation point and path of the NRLNs were localized and identified precisely with IONM. The NRLN was observed during all surgeries. These four cases did not exhibit hoarseness after surgery. In conclusion, understanding of the course variations of the right subclavian artery using a preoperative CT examination provides an indicator of the presence of a NRLN. Combining these evaluation methods with IONM can avoid NRLN injury.

Efficacy of ultrasonography in identification of non-recurrent laryngeal nerve.

BACKGROUND: The aim of this prospective study was to identify the arterial anomalies constantly associated with nonrecurrent inferior laryngeal nerve by preoperative ultrasonography and impact on recurrent inferior laryngeal nerve palsy (RILN). METHOD: The study included 332 patients who underwent thyroidectomy or parathyroidectomy between 2009 February and 2011 October. Preoperative ultrasonography was performed to all patients to identify vascular anomalies related to NRILN. CT was performed only in patients with NRILN predicted with preoperative ultrasonography. Systematic nerve dissection was performed surgically. Patient characteristics, type of NRILN, preoperative and postoperative vocal cord mobility and morbidity were recorded. RESULTS: The NRILN was identified in 6 patients on the right side (1.94%). Preoperative ultrasonography predicted NRILN in all cases (accuracy 100%). CONCLUSION: Ultrasonography is a very reliable and simple method to be used in preoperative assessment to identify vascular anomaly associated with NRILN to make optimal surgical decisions against nerve damage in patients undergoing thyroidectomy or parathyroidectomy. Adequate surgical technique is of great importance.

A method for ultrasonographic visualization and injection of the superior laryngeal nerve: volunteer study and cadaver simulation.

Superior laryngeal nerve block is a valuable technique for provision of upper airway anesthesia. In bilateral scans of 20 volunteers, we developed a technique for ultrasonographic visualization of the superior laryngeal nerve and key anatomical structures using a hockey stick-shaped 8 to 15 MHz transducer (HST15 to 8/20 linear probe, Ultrasonix, Richmond, BC, Canada). Subsequently, we simulated superior laryngeal nerve scanning and injection in bilateral injections in 2 cadavers. Ultrasound-guided in-plane advancement of a needle toward the superior laryngeal nerve and injection of 1 mL of green dye was achieved in all 4 attempts and confirmed by a postprocedural dissection performed by an anatomist. We conclude that ultrasound-guided superior laryngeal nerve block in humans may be feasible.