Animal study: Basic mechanism of vocal cord paralysis caused by button battery ingestion in children.

PURPOSE: Vocal cord paralysis has been reported as a common complication of button battery (BB) ingestion, and there is a need to confirm the mechanism of vocal cord paralysis for the development of a standardized treatment. METHODS: A new CR2032 BB and artificial saliva were placed in a fresh pig esophagus with the recurrent laryngeal nerve (RLN); the negative electrode faced the nerve in the experimental group, while the positive electrode faced the nerve in the control group. The pH values of the intra- and extraesophageal walls were measured simultaneously. Pathological examination was performed after the esophagus and nerves were damaged. RESULTS: After BB ingestion, the pH near the intraesophageal negative electrode increased rapidly, reaching 11.5 at 30 min and over 14 at 6 h, while the extraesophageal pH did not change at 1 h and began to accelerate after 2 h, reaching 10 at 6 h. After 6 h of exposure, the pathological section showed that the structure of the mucosa, submucosa, and muscle layer were destroyed; chromatin in the nucleus faded, and part of the nerve bundle in the adventitia had liquefaction necrosis. CONCLUSION: The basic mechanism of vocal cord paralysis caused by BB ingestion is that the OH- generated by the electrolytic reaction of the negative electrode penetrates the esophageal wall and corrodes the RLN, which may be the cause of vocal cord paralysis caused by BB ingestion without esophageal perforation.

[Clinical application of modified fistulectomy in the treatment of congenital pyriform sinus fistula based on segmental anatomy of fistula].

Objective:To discuss the clinical application and significance of the modified piriform fossa fistulectomy based on segmental anatomy of fistula. Methods:The clinical data of 84 patients with CPSF treated by modified pyriform sinus fistulectomy were analyzed retrospectively. The modified piriform fossa fistula resection adopts the fistula anterograde anatomy method to fine dissect the fistula. The operation procedure can be summarized into four parts: retrograde anatomy of recurrent laryngeal nerve, anatomy of external branch of superior laryngeal nerve, anterograde anatomy of fistula and partial thyroidectomy. Results:All 84 patients successfully completed the operation and discharged from the hospital. The operation time was（64.6±20.0） min, the intraoperative bleeding was（19.6±13.0） mL, and the average hospital stay was（6.8±1.1） d. Postoperative infection occurred in 1 case（1.19%）, temporary vocal cord paralysis in 1 case（1.19%）, no bleeding, pharyngeal fistula, dysphagia, permanent vocal cord paralysis and choking cough. The incidence of complications was 2.3%（2/84）. No complications such as permanent vocal cord paralysis and hypothyroidism occurred. Follow up for 57-106（Median 74） months showed no recurrence. Conclusion:A modified procedure based on segmental dissection of the fistula not only simplifies the traditional procedure, but also procedures the specific steps to provide a targeted and precise resection, which provides a proven surgical solution for complete eradication of the lesion and significantly reduces complications and recurrence.

To Explore the Changes and Differences of Microstructure of Vocal Fold in Vocal Fold Paralysis and Cricoarytenoid Joint Dislocation by Diffusion Tensor Imaging.

OBJECTIVE: The diffusion characteristics of water molecules were measured in the vocal folds of canines exhibiting unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation. These characteristics were used in conjunction with a histological examination of the microstructural changes of vocal fold muscle fibers to explore the feasibility of diffusion tensor imaging (DTI) in distinguishing unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation as well as evaluating microstructural changes. METHODS: Ten beagles were randomly divided into three groups: four in the unilateral vocal fold paralysis group, four in the unilateral cricoarytenoid joint dislocation group, and two in the normal group. Unilateral recurrent laryngeal nerve resection was performed in the vocal fold paralysis group. Unilateral cricoarytenoid joint dislocation surgery was performed in the dislocation group. No intervention was performed in the normal group. Four months postintervention, the larynges were excised and put into a magnetic resonance imaging (MRI) system (9.4T BioSpec MRI, Bruker, German) for scanning, followed by an analysis of diffusion parameters among the different groups for statistical significance. After MRI scanning, the vocal folds were cut into sections, stained with hematoxylin and eosin, and scanned digitally. The mean cross-sectional area of muscle fibers, and the mean diameter of muscle fibers in the vocal folds were calculated by target detection and extraction technology. Mean values of each measurement were used to compare the differences among the three groups. Pearson correlation analysis was performed on the DTI parameters and the results from histological section extraction. RESULTS: The paralysis group had significantly higher Fractional Anisotropy (FA) compared to the dislocation group and normal group (P = 0.004). The paralysis group also had a significantly lower Tensor Trace value compared to the dislocation group and normal group (P = 0.000). The average cross-sectional area of vocal fold muscle fibers in the paralysis group was significantly smaller than the dislocation group and normal group (P = 0.000). Pearson correlation analysis yielded values of, r = -0.785, P = 0.01 between the average cross-sectional area of vocal muscle fibers and FA, and values of r = 0.881, P = 0.00 between Tensor Trace and the average cross-sectional area of vocal muscle. CONCLUSION: FA and Tensor Trace can be used as effective parameters to reflect the changes of microstructure in vocal fold paralysis and cricoarytenoid joint dislocation. DTI is an objective and quantitative method to effectively evaluate unilateral vocal fold paralysis and unilateral cricoarytenoid joint dislocation, also capable of noninvasively evaluating vocal fold muscle fiber microstructure.

The Regenerative Effects of c-Met Agonistic Antibodies in Vocal Fold Atrophy.

BACKGROUND: Atrophy of the vocal folds and the accompanying glottic insufficiency affect the quality of life. Although growth factors have been used to treat muscle atrophy, their effectiveness is limited by their short half-life. METHODS: In total, 15 rabbits and 24 rats were used for the study. The right recurrent laryngeal nerves of all animals were transected. One month following nerve transection, PBS (PBS group), rHGF (HGF group), or a c-Met agonistic antibody (c-Met group) was injected into the paralyzed vocal folds. The larynges of the rabbits were harvested from each group for histologic examination and subjected to PCR analysis. RESULTS: Cross-sectional areas (CSAs) of thyroarytenoid muscles were evaluated. The c-Met group had increased CSAs compared to the PBS and HGF groups, but there were no significant differences compared to normal controls. The expression levels of myogenesis-related genes were evaluated three weeks after the injection. The expression levels of myosin heavy chain IIa were significantly increased in the PBS group, while the expression levels of MyoD were increased in the c-Met group. CONCLUSIONS: The c-Met agonistic antibody showed promise for promoting muscle regeneration in a vocal fold palsy model.

Laryngoscopic findings of age-related vocal fold atrophy are reliable but not specific.

OBJECTIVES: We aimed to evaluate the reliability of laryngoscopic features of vocal fold atrophy as assessed by novice otolaryngology trainees and expert laryngologists. DESIGN: Two expert fellowship-trained laryngologists and three non-expert otolaryngology resident trainees were recruited to view 50 anonymised laryngo-stroboscopic examinations of patients presenting with dysphonia and non-voice, laryngeal complaints. Reviewers were asked to stratify the patient's age, provide an opinion about the presence of age-related vocal fold atrophy and specify which laryngoscopy features were present to make the diagnosis. SETTING: Tertiary care laryngology practice. PARTICIPANTS: Two fellowship-trained laryngologists and three trainee otolaryngologists. MAIN OUTCOME MEASURES: Accuracy of age categorisation was determined and Kappa analysis was performed to assess inter-rater agreement. RESULTS: The mean age of patients was 54.9 years old with near equal male to female distribution. The overall accuracy of age category determination by raters was only 30.8%. Kappa analysis demonstrated fair agreement regarding the presence of vocal fold atrophy in non-expert reviewers, and moderate agreement amongst expert reviewers. Features of glottic gap, muscular atrophy of vocal folds and prominent vocal processes were all identified with high agreement (>80.0%). CONCLUSION: Our study illustrates that while raters can agree on the presence of age-related vocal fold atrophy, the findings may be non-specific and do not necessarily correlate with age.

Smoking-induced radiation laryngeal necrosis after definitive radiotherapy alone for T1a glottic squamous cell carcinoma: A case report.

BACKGROUND: We report the case of a patient with smoking-induced radiation laryngeal necrosis (RLN) after undergoing definitive radiotherapy (RT) alone for T1a glottic squamous cell carcinoma. CASE: The patient was a 63-year-old man who had a history of heavy smoking. He quit smoking when he was diagnosed with glottic squamous cell carcinoma. The RT dose was 63 Gy, delivered in 28 fractions with the three-dimensional conventional RT technique for the larynx. After RT completion, the initial treatment response was complete response. He then underwent follow-up examinations. At 13 months after RT, the patient resumed smoking. At 2 months after resuming smoking, he had severe sore throat and hoarseness. Laryngoscopy revealed a large tumor in the glottis. Surgical excision was performed, and the patient was histologically diagnosed with RLN, as late toxicity without cancer recurrence. At 3 weeks postoperatively, the patient had dyspnea, and laryngoscopy revealed total laryngeal paralysis. Thus, he underwent an emergent tracheostomy. The administration of steroids affected RLN, and laryngeal paralysis gradually improved. CONCLUSIONS: This case suggests that smoking may have the potential to induce RLN after RT. Moreover, continuing smoking cessation is significantly important for patients with glottic cancer who receive RT. Rather than leaving smoking cessation up to the patient, it would be necessary for clinicians to actively intervene to help patients continue their effort to quit smoking.

Autologous Lipoaugmentation Long-Term Clinical Outcomes: A Systematic Review.

OBJECTIVES/HYPOTHESIS: Vocal fold (VF) lipoaugmentation can be employed to treat glottal insufficiency although variable data exist on its length of effectiveness. We aimed to review published long-term outcomes following lipoaugmentation across the literature and compile outcome data. STUDY DESIGN: Systematic review. METHODS: A systematic search in September 2020 of PubMed, MEDLINE, Cochrane Library, and Web of Science used the Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines to identify 128 relevant articles related to VF lipoaugmentation effectiveness duration. Primary search terms included the following: vocal cord, fat, lipo, and atrophy. Forty-eight full-text articles were reviewed and 31 were included in the final analysis. Primary endpoints included the following: duration of effectiveness per patient-reported outcome measures, objective findings, and additional procedures performed. In addition, fat harvest location and processing techniques were recorded. FINDINGS: Thirty-one studies totaling 764 patients were included in the review. Indications for augmentation were VF paralysis (N = 690) and atrophy (N = 74). Fat was harvested from the abdominal region in 21 studies (529 patients), the thigh/abdomen in 5 studies (91 patients), and buccal/submental region in 2 studies (33 patients). Processing techniques and injectable volume varied. Across included studies, only 11 of 764 patients (1.4%) reported no improvement in voice and/or swallowing. Within the first year, 71 of 608 patients (11.7%) reported a regression toward baseline. Beyond 1 year and up to 8 years, 27 of 214 patients (12.6%) reported regression from initial improvement. Thirty-three patients underwent additional procedures. CONCLUSION: Although improvements in voice and swallowing after lipoaugmentation taper over time, most patients experienced long-term benefit. Laryngoscope, 132:1042-1053, 2022.

Postoperative recurrent laryngeal nerve palsy is associated with pneumonia in minimally invasive esophagectomy for esophageal cancer.

BACKGROUND: During the past decade, minimally invasive esophagectomy (MIE) for esophageal cancer has been adopted worldwide with expectations of lower invasiveness. However, the rate of postoperative pneumonia, which is an independent risk factor for oncological prognosis in esophageal cancer, remains high. The aim of this retrospective follow-up study is to clarify whether there is a strong correlation between recurrent laryngeal nerve (RLN) palsy and postoperative pneumonia in MIE. METHODS: This retrospective follow-up study included 209 patients with esophageal cancer who underwent thoracoscopic esophagectomy in the prone position (TEP) at Kobe University between 2011 and 2018. Inclusion criteria included age 18-85 years; cT1-3, cN0-3 disease; upper mediastinal lymphadenectomy; and ability to undergo simultaneous esophagectomy and reconstruction of the gastric conduit or pedicled jejunum. Univariate and multivariate logistic regression were conducted to identify independent risk factors for pneumonia. RESULTS: Among 209 TEPs, pneumonia of Clavien-Dindo classification grade > II occurred in 44 patients (21%). In the pneumonia positive and negative groups, there were significant differences in age (67.9 ± 7.5 vs. 64.9 ± 8.6 years), 3-field lymph node dissection [27 (61%) vs. 67 (41%)], transfusion [20 (45%) vs. 41 (25%)], left RLN palsy [19 (43%) vs. 18 (11%)], and any RLN palsy [20 (45%) vs. 18 (11%)]. In multivariate analysis, any RLN palsy was associated with a higher incidence of pneumonia [odds ratio (OR), 6.210; 95% confidence interval (CI), 2.728-14.480; P < 0.0001]. In addition, age was associated with a higher incidence of pneumonia (OR, 1.049; 95% CI, 1.001-1.103; P = 0.046). Changes in the rate of any RLN palsy over time were quite similar to changes in the incidence of pneumonia. CONCLUSION: There is a strong correlation between RLN palsy and pneumonia in MIE for esophageal cancer. Prevention of RLN palsy may reduce the incidence of pneumonia, leading to better oncological prognosis.

Fibrin Gel Suspended Autologous Chondrocytes as Cell-based Material for long-term Injection Laryngoplasty.

OBJECTIVES/HYPOTHESIS: Injection laryngoplasty of materials for unilateral vocal-fold paralysis has shown various results regarding the long-term stability of the injected material. We evaluated a fibrin-gel based cell suspension with autologous chondrocytes in-vitro and in-vivo as long-term-stable vocal-fold augmentation material in an animal model. STUDY DESIGN: This study compises an in vitro cell-culture part as well as an in vivo animal study with New Zealand White Rabbits. METHODS: In in-vitro experiments, auricular chondrocytes harvested from 24 New Zealand White Rabbits cadavers were cultivated in pellet cultures to evaluate cartilage formation for 4 weeks using long-term-stable fibrin gel as carrier. Injectability and injection volume for the laryngoplasty was determined in-vitro using harvested cadaveric larynxes. In-vivo 24 Rabbits were biopsied for elastic cartilage of the ear and autologous P1 cells were injected lateral of one vocal cord into the paraglottic space suspended in a long-term-stable fibrin gel. Histologic evaluation was performed after 2, 4, 12, and 24 weeks. RESULTS: During 12-week pellet culture, we found extracellular matrix formation and weight-stable cartilage of mature appearance. In-vivo, mature cartilage was found in two larynxes (n = 6) at 4 weeks, in four (n = 6) at 12 weeks, and in five (n = 6) at 24 weeks mostly located in the paraglottic space and sometimes with spurs into the vocalis muscle. Surrounding tissue was often infiltrated with inflammatory cells. Material tended to dislocate through the cricothyroid space into the extraglottic surrounding tissue. CONCLUSIONS: A cell-based approach with chondrocytes for permanent vocal-fold augmentation has not previously been reported. We have achieved the formation of structurally mature cartilage in the paraglottic space, but this is accompanied by difficulties with dislocated material, deformation of the augmentation, and inflammation. LEVEL OF EVIDENCE: N/A Laryngoscope, 131:E1624-E1632, 2021.

Medialization Thyroplasty and Arytenoid Adduction for Management of Neurological Vocal Fold Immobility.

Vocal fold immobility can be either unilateral or bilateral and partial or complete. The aim of this chapter is to discuss the management of unilateral paresis using medialization thyroplasty with or without arytenoid adduction as a means of treating neurogenic causes as opposed to mechanical fixation. Medialization thyroplasty is an open surgical procedure that is performed under local or general anesthesia. Essentially, it aims to close the glottic gap, approximating both vocal folds together and thereby allowing for restoration of the efficiency of the larynx. The glottic gap results from atrophy of the affected vocal fold and in so doing results in glottic insufficiency which causes voice breathiness, strain, fatigue, aspiration, and swallowing difficulties that make up the bulk of symptoms associated with this condition. Unlike injection laryngoplasty, medialization thyroplasty does not increase the "bulk" of the atrophic vocal fold but merely brings the fold closer to its unaffected partner. Besides the obvious lateralization, there is occasionally a third dimensional component to the affected fold. The slipping and prolapse forward of the arytenoid cartilage due to atrophy of the muscles supporting it and the natural declination of the facet joint it rests on cause a vertical drop of the level of the affected vocal fold that may not be remedied with the medialization procedure, hence requiring arytenoid adduction. Although attempts to medialize the vocal fold have been described in the past with limited access, the basic premise of creating a window in the thyroid cartilage remains central. The differences between materials used, their respective strengths and weaknesses, the pitfalls and pearls in achieving a good closure and improvement in voice, swallow, and safety of the airway are all discussed accordingly.

Recent advances in minimally invasive esophagectomy for squamous esophageal cancer.

Over the past decade there has been tremendous development in the clinical application of minimally invasive esophagectomy (MIE) for the treatment of squamous esophageal carcinoma. The major challenges in the performance of MIE include limitations in visualization and manipulation within the confined, rigid thoracic cavity; the need for adequate patient positioning and anesthetic techniques to accommodate the surgical exposure; and changes in the surgical steps for achieving radical nodal dissection, especially for the superior mediastinum. The surgical procedure for MIE is more and more standardized, and there is an increasing practice of MIE worldwide. Randomized trials and meta-analyses have confirmed the advantages of MIE over open esophagectomy, including a significantly lower rate of complications and shorter hospital stays. The recent application of robotics technologies for MIE has further enhanced the quality and safety of the surgical dissection, while intraoperative nerve monitoring has contributed to a lower rate of recurrent laryngeal nerve palsy. With the application of new technologies, we expect further improvement in surgical outcomes for MIE in the treatment of squamous esophageal cancer.

Polyneuropathy in Young Siberian Huskies Caused by Degenerative and Inflammatory Diseases.

Polyneuropathy is defined as the simultaneous dysfunction of several peripheral nerves. In dogs, a number of breeds are predisposed to a variety of immune-mediated and/or degenerative inherited forms of polyneuropathy, with laryngeal paralysis and/or megaesophagus as important clinical features of many of these conditions. This case series describes degenerative and inflammatory polyneuropathies in 7 young Siberian huskies that were categorized based on clinicopathological characteristics as follows: (1) slowly progressive laryngeal paralysis and megaesophagus caused by primary axonal degeneration with large fiber loss (n = 2); (2) slowly progressive polyneuropathy without megaesophagus or laryngeal paralysis caused by primary axonal degeneration with large fiber loss (n = 2); (3) acute inflammatory demyelinating neuropathy causing sensory, motor and autonomic nerve deficits (n = 2); and (4) ganglioradiculitis (sensory neuronopathy; n = 1). Based on the predominantly young age at onset, slow progression, relatedness of affected dogs, and clinical and pathological similarities with inherited neuropathies reported in other dog breeds, a hereditary basis for the degenerative polyneuropathies in Siberian huskies is suspected. However, 5 different mutations in 3 genes known to cause polyneuropathy in other dog breeds (NDRG1, ARHGEF10, or RAB3GAP1) were not detected in the affected Siberian huskies suggesting that more genetic variants remain to be identified. This study highlights the varied underlying lesions of polyneuropathies in young Siberian huskies.

An Autopsy Case of Idiopathic Pleuroparenchymal Fibroelastosis with Left Vocal Cord Paralysis and a Rapid Deterioration without an Acute Exacerbation.

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a generally slow-progressing rare disorder of unknown etiology. The direct cause of death in cases of IPPFE is rarely investigated. We experienced an autopsy case of a Japanese man with IPPFE and found aspiration pneumonia to be the major trigger of death. The individual had left vocal cord paralysis at admission, which may have contributed to aspiration pneumonia, and which probably was affected by the fibrous adhesion of the left apex of the chest wall resulting from IPPFE. The prevention of aspiration pneumonia is important for maintaining the respiratory function, especially in IPPFE patients with repeated pneumothorax.

Assessing pathological changes within the nucleus ambiguus of horses with recurrent laryngeal neuropathy: An extreme, length-dependent axonopathy.

INTRODUCTION: Equine recurrent laryngeal neuropathy (RLN) is a naturally occurring model of length-dependent axonopathy characterized by asymmetrical degeneration of recurrent laryngeal nerve axons (RLn). Distal RLn degeneration is marked, but it is unclear whether degeneration extends to include cell bodies (consistent with a neuronopathy). METHODS: With examiners blinded to RLN severity, brainstem location, and side, we examined correlations between RLN severity (assessed using left distal RLn myelinated axon count) and histopathological features (including chromatolysis and glial responses) in the nucleus ambiguus cell bodies, and myelinated axon count of the right distal RLn of 16 horses. RESULTS: RLN severity was not associated with RLn cell body number (P > .05), or degeneration. A positive correlation between the left and right distal RLn myelinated axon counts was identified (R2 = 0.57, P < .05). DISCUSSION: We confirm that RLN, a length-dependent distal axonopathy, occurs in the absence of detectable neuronopathy.

Could the infiltration of the thyroarytenoid muscle define the pT2 glottic carcinoma?

BACKGROUND: The involvement of the thyroarytenoid (TA) muscle by glottic cancer may be related to an impaired vocal cord mobility, which is classified as cT2 disease. The primary endpoint was to evaluate the prognostic significance of TA muscle involvement in early glottic cancer treated with transoral laser microsurgery (TLM). METHODS: A review was conducted on a cohort of 209 patients consecutively treated with TLM for early glottic carcinoma. Univariate analysis was used to examine the prognostic meaning of clinical and pathological parameters. RESULTS: The statistical analysis showed that TA muscle infiltration correlated significantly with a worse prognosis in terms of recurrence rate and disease-free survival, and this was confirmed even in the subcohort with pT1a glottic cancer. CONCLUSIONS: Our preliminary findings suggest that it could be considered as a criterion for upstaging a glottic cancer from pT1 to pT2.

Quality of Voice and Prognostic Markers for the Recovery of Vocal Fold Paralysis After Thyroid Surgery.

OBJECTIVES: This study is set to analyze clinicopathological factors predicting the recovery of unilateral vocal fold paralysis (UVP) in patients after thyroid gland surgery. The quality of voice was additionally assessed in these patients. METHODS: The charts and videolaryngostroboscopy (VLS) examinations of 84 consecutive patients with a complete UVP after surgery of the thyroid gland were retrospectively reviewed. Patients were divided into 2 groups: patients who fully recovered from vocal fold paralysis and those who failed to recover after a follow-up of 12 months. The quality of voice was analyzed among other things by determining the Voice Handicap Index (VHI). RESULTS: The UVP fully recovered in 52 of 84 (61.9%) patients. Positive mucosal waves (pMWs) on the paralyzed side, a minimal glottic gap <3 mm seen at the first postoperative VLS, age ≤50 years, and surgery duration ≤120 minutes were associated factors for a complete recovery of nerve function. The voice parameters improved independently from recovery of the paralysis in 90% of the patients. CONCLUSIONS: For patients with a poor prognosis of a UVP, early intervention may be beneficial. Thus, predicting factors for a full recovery of vocal fold motion would be a valuable tool. In our cohort, about 60% of recoveries could have been predicted using the above-mentioned parameters. Good quality of voice was independently reached in 90% of the cases.

Anesthetic Considerations of Intraoperative Neuromonitoring in Thyroidectomy.

BACKGROUND: Intraoperative neuromonitoring (IONM) might reduce the incidence of injury to the recurrent laryngeal nerve (RLN) during thyroidectomy. Although dislocation of endotracheal tube surface electrodes can lead to false-positive IONM results (loss of signal), the risk factors for dislocation and the effects of muscle relaxants are unclear. Therefore, to identify factors that affect IONM results, we examined the frequency and risk factors for tube dislocation after cervical extension before surgery, the effect of sugammadex administration, and the correlation between IONM results and postoperative RLN palsy. METHODS: Thirty-nine patients scheduled for thyroidectomy from October 2016 to April 2017 were enrolled. All patients underwent standard IONM and pre- and postoperative laryngoscopy. Differences in patient characteristics in the tube dislocation group and non-dislocation group, and differences in amplitude during vagal stimulation before and after sugammadex administration, were assessed by the Mann-Whitney test or Fisher's exact test. RESULTS: Tube dislocation occurred in 27 patients (69%). Sterno-cricoid distance was significantly shorter in the dislocation group (n=27) than in the non-dislocation group (n=12) (43.88 [32.2-55.91] mm vs 49.46 [40.66-55.91] mm, respectively; p=0.048). Without sugammadex, amplitude during vagal stimulation was sufficient for monitoring. Nine patients had new-onset RLN palsy, which was transient in all patients. The sensitivity of IONM was 100%, the positive predictive value was 60%, and the negative predictive value was 100%. CONCLUSIONS: The present findings suggest that anesthesiologists should use video laryngoscopy to correct tube dislocation and that a rocuronium dose of 0.6 mg/kg, without sugammadex, is adequate for IONM.

Using intraoperative optical coherence tomography to image pediatric unilateral vocal fold paralysis.

OBJECTIVES: Unilateral vocal fold paralysis (UVFP) impairs communication and reduces academic performance and social interactions in children. Deciding between temporary, permanent, or potentially destructive surgical interventions can be challenging, as there currently exists no reliable means of predicting vocal fold recovery or assessing the presence of vocal fold atrophy. Regarding vocal fold atrophy, optical coherence tomography (OCT) has been shown to be an appealing non-invasive alternative for accessing vocal fold structures. This study describes UVFP microanatomy and identifies possible vocal fold atrophy using OCT. METHODS: Three UVFP patients (ages 1, 11, and 17 years) underwent bilateral OCT imaging using a handheld probe while under general anesthesia for direct laryngoscopy, and the laryngoscopic images were compared with images obtained from OCT. Structural morphological features were extracted and compared to a healthy patients' cohort. RESULTS: While endoscopy showed no evidence of vocal fold atrophy in two of three cases, OCT images revealed distinct differences between the lamina propria of the paralyzed and functional vocal folds in all patients. In two cases, the paralyzed vocal fold morphology was similar to a healthy patient at the age of nerve injury. The third case exhibited extensive scarring in the lamina propria of the paralyzed vocal fold. CONCLUSION: This pilot study characterizes and compares vocal fold microanatomy in three UVFP patients. In most cases, lamina propria development halted at the age of paralysis, suggesting that lamina propria maturation may be dependent on vocal fold functionality. OCT shows potential to aid UVFP assessment and treatment decisions by evaluating the presence of atrophy.