Assessment of pre-extubating recurrent laryngeal nerve palsy using ultrasound in postoperative patients with esophageal cancer: a prospective observational study.

PURPOSE: Ultrasound performed after extubation has been suggested to be useful for the diagnosis of recurrent laryngeal nerve (RLN) paralysis. However, the use of ultrasound for this purpose before extubation has not been examined. The aim of this study was to examine the versatility (interrater reliability) and usefulness of ultrasound for evaluating the movement of vocal cords before extubation. METHODS: The subjects were 30 patients who underwent radical surgery for esophageal cancer from August 2020 to December 2021. An experienced examiner performed an ultrasound examination before and after elective extubation on the day after surgery to evaluate RLN paralysis and record videos. Bronchoscopy was then performed to make a definite diagnosis. Three anesthetists blinded to the diagnosis also evaluated the cases using the videos, and the versatility of the examination was determined using a kappa test. RESULTS: The diagnostic accuracies of the examiner and three anesthetists were 76.7%, 50.0%, 53.3%, and 46.7%, respectively, and the kappa coefficients for the examiner with the anesthetists were 0.310, 0.502, and 0.169, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for diagnosis of RLN paralysis by the examiner using ultrasound before extubation were 0.57, 0.95, 0.80, and 0.87, respectively. CONCLUSION: These results indicate a lack of versatility of the ultrasound examination based on the low kappa coefficients. However, with an experienced examiner, ultrasound can serve as a non-invasive examination that can be performed before extubation with high accuracy and specificity for diagnosis of postoperative RLN paralysis.

Establishment and characterization of immortalized human vocal fold fibroblast cell lines.

PURPOSE: Vocal fold scarring is abnormal scar tissue in the lamina propria layer of the vocal fold. To facilitate investigation of vocal fold scarring, we established and characterized immortalized human vocal fold fibroblast (iHVFF) cell lines. METHODS: Human vocal fold fibroblasts were immortalized by introducing Simian virus 40 large T antigen (SV40TAg) by transfection. Successfully transfected fibroblasts were sorted using flow cytometry. Immunofluorescence cytochemistry and western blot were applied to analyze the expression of fibronectin, vimentin, alpha-smooth muscle actin (α-SMA) and fibroblast activation protein (FAP). Cell proliferation rate was measured by CCK-8 assay. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to analyze the mRNA expression level. RESULTS: The iHVFFs continued to proliferate for more than 30 generations and appeared spindle-shaped. The expression of Vimentin and α-SMA were detected in both iHVFFs and primary fibroblasts, and enhanced expression of FAP was observed in iHVFFs. Furthermore, iHVFFs exhibited an increased proliferative capability compared with the primary fibroblasts. RT-qPCR results suggested that collagen type III alpha 1 chain (COL3A1), interleukin-6, cyclooxygenase 2 (COX2), hyaluronan synthase 2 (HAS2), hepatocyte growth factor (HGF) in the iHVFFs significantly increased, whereas transforming growth factor-ß1 (TGF-ß1), elastin and matrix metallopeptidase-1 (MMP-1) expression significantly downregulated. No differences in mRNA expression of α-SMA, fibronectin and collagen type I alpha 2 chain (COL1A2) were noted between iHVFFs and primary fibroblasts. CONCLUSION: iHVFFs can be used as a novel tool cell for future researches on the mechanisms of pathogenesis and treatment of vocal fold scarring.

A Scoping Review of Ultrasonographic Techniques in the Evaluation of the Pediatric Airway.

Point-of-care ultrasound is making rapid advancements in pediatrics, and ultrasonographic assessment of the airway is being employed in many specialties such as the pediatric, cardiac, and neonatal intensive care units, emergency department, pulmonary clinic, and the perioperative setting. This scoping review provides a technical description of image acquisition and interpretation, accompanying ultrasound images of the hallmark airway applications in pediatrics, and supporting evidence when available. We describe and illustrate ultrasound-determined endotracheal tube (ETT) sizing, ETT placement and depth confirmation, vocal fold assessment, prediction of post-extubation stridor, difficult laryngoscopy prediction, and cricothyrotomy guidance. This review aims to provide the descriptions and images necessary to learn and apply these skills at the point of care in the pediatric patient.

Timing of True Vocal Cords Closure for Safe Swallowing: A Review of 5 Studies Using 3D Analysis Using Computerized Tomography (CT).

Timely and complete laryngeal closure is critical for a successful swallow. Researchers have studied laryngeal closure, including true vocal cords (TVC) closure, closure of the arytenoids to the epiglottis base (laryngeal vestibule closure), and epiglottic inversion, but the most commonly available imaging tools have limitations that do not allow the study of these components individually. Swallowing computerized tomography (CT) has enabled three-dimensional dynamic visualization and quantitative evaluation of swallowing events providing a unique view of swallowing-related structures and their motion. Using CT, TVC closure can be visualized and evaluated on any plane or cross-section without being obscured by of laryngeal vestibule closure or epiglottis inversion. The current review summarizes the results of five papers evaluating the effects of bolus consistency and volume, posture, and age on TVC closure. The combined results of these studies suggest that TVC closure is responsive to oral sensory input based on bolus consistency and size and can be modulated in response to conditions perceived to increase the risk of airway invasion. These results are meaningful for dysphagia rehabilitation as it suggests that interventions to improve TVC closure are likely to enhance airway protection.

Surgical management of broad-based sessile vocal cord polyps: Transnasal vocal fold polypectomy versus microlaryngoscopic surgery: Our experience in 159 cases.

OBJECTIVES: In this study, we retrospectively reviewed and compared the treatment outcomes and complications of office transnasal vocal fold polypectomy (TVFP) with those of microplarygoscopic surgery (MLS) for different clinical and histopathological features of broad-based sessile vocal fold polyps. METHODS: We retrospectively reviewed the records of 159 consecutive patients with broad-based sessile vocal fold polyps treated by TVFP or MLS. The differences in efficacy and complication between these two surgical techniques were compared according to the different types of vocal fold polyps. RESULTS: Satisfactory outcomes of both TVFP and MLS treatments were reported in patients with oedematous, gelatinous and vascular types of vocal fold polyps (p > .05). The efficacy of TVFP was slightly worse than MLS in fibrous polyps group (p < .05). The TVFP-treated patients did not exhibit obvious complications, whereas several MLS-treated patients had suffered different complications. CONCLUSION: The therapeutic effects of both TVFP and MLS on the treatment of broad-based sessile vocal cord polyps are related to their clinical characteristics and histological types. Satisfactory outcomes are achieved in oedematous, gelatinous, and vascular types of polyps after either surgical procedure. TVFP has fewer surgical complications than MLS which can be a preferred option for the treatment of broad-based sessile vocal cord polyps at outpatient setting. TVFP also can be an alternative surgery option for patients who could not tolerate general anaesthesia or laryngeal suspension. In contrast, MLS has proven to be a particularly advantageous treatment in patients who have fibrous type of polyps.

Transection Of Sternothyroid Muscle Increases The Rate Of Exposure Of The External Branch Of The Superior Laryngeal Nerve During Thyroidectomy.

Objectives: To assess the benefits of transection of the sternothyroid muscle compared to conventional approach for detecting the external branch of the superior laryngeal nerve while dealing with the upper pole of the thyroid gland. METHODS: The randomised controlled clinical trial was conducted at Kafrelsheikh University Hospital, Egypt, from January 2021 to January 2022, and comprised patients who were eligible for total thyroidectomy and met the American Thyroid Association guidelines. They were randomised and divided into conventional approach group A and sternothyroid muscle transection approach group B. The rate of exposure of the external branch of the superior laryngeal nerve, injury, classification, operative time and voice outcomes at 2 weeks and 3 months post-intervention were noted in both the groups. Data was analysed using SPSS 22. RESULTS: Of the 102 patients, 50(49%) were in group A; 5(10%) males and 45(90%) females with mean age 40.48±12.58 years and mean body massindex 30.676±2.305. There were 52(51%) patientsin group B; 5(9.6%) males and 45(90.4%) females with mean age 39.67±11.60 years and mean body mass index 30.096±2.776. The rate of external branch of the superior laryngeal nerve identification was higher and the operative time was shorter in group B compared to group A (p=0.05). No significant difference was noted in terms of voice outcomes either at baseline or at any of the two follow-up points between the groups (p>0.05). CONCLUSIONS: The transection of sternothyroid muscle improved the rate of external branch of the superior laryngeal nerve exposure and preservation compared to the conventional technique during thyroidectomy.

Advances in Organ Preservation for Laryngeal Cancer.

OPINION STATEMENT: At the University of Wisconsin, all treatment of head and neck cancer patients begins with discussion at our multi-disciplinary tumor board. Most patients with T4 disease, with existing laryngeal dysfunction, considered unlikely to complete definitive CRT or who have a high risk of persistent aspiration after non-operative management undergo total laryngectomy. A laryngeal sparing approach is attempted on most other patients. Radiotherapy is delivered over 6.5 weeks, preferably with concurrent weekly cisplatin. If the patient is hesitant of chemotherapy or has contraindications to cisplatin, concurrent cetuximab may be offered. Patients treated with RT alone are often treated to the same dose, but via an accelerated schedule by adding a 6th fraction per week. The 6th fraction is given by delivering two treatments at least 6 h apart on a weekday of the patient's choosing. We consider the following to be major risk factors for clinically significant weight loss during treatment: a 10% or greater loss of weight in the 6 months prior to starting treatment, delivery of concurrent cisplatin, and treatment of the bilateral neck with radiation. Patients who have 2-3 of these characteristics are often given gastrostomy tubes prophylactically. Patients are seen 2 weeks after completion of therapy, and then every 3 months after completion for 2 years. A CT neck and PET-CT are performed at the first 3-month visit. They are seen twice in year three, and then yearly until years 5-7. At each of these visits, we have a low threshold to present the patient at our multidisciplinary tumor board for consideration of salvage laryngectomy if there are signs of progression.

Facemask ventilation and vocal cord angle following neuromuscular blockade: a prospective observational study.

Numerous studies support the idea that neuromuscular blockade facilitates facemask ventilation after induction of anaesthesia. Although improved airway patency or pulmonary compliance and a resolution of laryngospasm have been suggested as possible causes, the exact mechanism remains unclear. We aimed to assess whether neuromuscular blockade improves facemask ventilation and to clarify whether this phenomenon is associated with the vocal cord angle. This prospective observational study included patients aged between 20 and 65 years scheduled for elective surgery under general anaesthesia. After induction of anaesthesia, patients' lungs were ventilated with pressure-controlled ventilation using a facemask. During facemask ventilation, a flexible bronchoscope was inserted through a self-sealing diaphragm at the elbow connector attached to the facemask and breathing circuit and positioned to allow a continuous view of the vocal cords. The mean tidal volume and vocal cord angle were measured before and after administration of neuromuscular blocking drugs. Of 108 patients, 100 completed the study. Mean (SD) tidal volume ((11.0 (3.9) ml.kg-1 vs. 13.6 (2.6) ml.kg-1 ; p < 0.001) and mean (SD) vocal cord angle (17° (10°) vs. 26° (5°); p < 0.001) increased significantly after neuromuscular blockade. The proportional increase in mean tidal volume after neuromuscular blockade was positively correlated with vocal cord angle (Spearman's ρ = 0.803; p < 0.001). In conclusion, neuromuscular blockade facilitated facemask ventilation, and the improvement was correlated with further opening of the vocal cords.

Modified Arytenoid Adduction Operation for the Treatment of Unilateral Vocal Fold Paralysis.

INTRODUCTION: Unilateral vocal fold paralysis (UVFP) was a relative common glottic insufficiency disease; however, a completely satisfactory treatment of UVFP was elusive. This study was aimed to evaluate the surgical efficacy of modified arytenoid adduction with fenestration of the thyroid cartilage in the management of patients with UVFP, including voice and aspiration outcomes, and to summarize the postoperative complications. METHODS: A retrospective analysis was performed on a total of 21 patients who underwent modified arytenoid adduction operation with fenestration of the thyroid cartilage for UVFP from July 2012 to June 2017. The scores of Grade, Roughness, Breathiness, Asthenia, Strain scale (GRBAS), voice self-satisfaction, dynamic laryngoscopy and the voice acoustic data (fundamental frequency [F0], fundamental frequency perturbation [jitter], loudness, amplitude perturbation [shimmer], and maximal phonatory time [MPT], etc.) were statistically analyzed preoperatively and 3-6 months postoperatively. The occurrence of postoperative complications was also summarized. RESULTS: The voice subjective perception of 21 patients was significantly improved after operation. The rate of voice self-satisfaction was 90.5%. The mean values of voice acoustics parameters were significantly improved. The MPT was significantly longer (p < 0.001), and the ratings of postoperative aspiration were significantly decreased compared with the preoperation. Among the 21 patients, 15 cases had sense of laryngeal obstruction, 8 cases had of 1-2° laryngemphraxis (recovered after 10-15 days). There were 2 cases of laryngeal stridor, 1 case of incision infection, 1 case of pharyngeal fistula, and 1 case of falsetto (corrected by voice training). No patient had laryngeal hematoma, neck hematoma, or laryngospasm. CONCLUSION: The modified arytenoid adduction operation with fenestration of the thyroid cartilage can significantly improve the vocal function of patients with UVFP and effectively reduce the aspiration, with fewer postoperative complications, less trauma, and more convenient advantages.

AI-Based Detection of Aspiration for Video-Endoscopy with Visual Aids in Meaningful Frames to Interpret the Model Outcome.

Disorders of swallowing often lead to pneumonia when material enters the airways (aspiration). Flexible Endoscopic Evaluation of Swallowing (FEES) plays a key role in the diagnostics of aspiration but is prone to human errors. An AI-based tool could facilitate this process. Recent non-endoscopic/non-radiologic attempts to detect aspiration using machine-learning approaches have led to unsatisfying accuracy and show black-box characteristics. Hence, for clinical users it is difficult to trust in these model decisions. Our aim is to introduce an explainable artificial intelligence (XAI) approach to detect aspiration in FEES. Our approach is to teach the AI about the relevant anatomical structures, such as the vocal cords and the glottis, based on 92 annotated FEES videos. Simultaneously, it is trained to detect boluses that pass the glottis and become aspirated. During testing, the AI successfully recognized the glottis and the vocal cords but could not yet achieve satisfying aspiration detection quality. While detection performance must be optimized, our architecture results in a final model that explains its assessment by locating meaningful frames with relevant aspiration events and by highlighting suspected boluses. In contrast to comparable AI tools, our framework is verifiable and interpretable and, therefore, accountable for clinical users.

Mechanisms of larynx and vocal fold development and pathogenesis.

The larynx and vocal folds sit at the crossroad between digestive and respiratory tracts and fulfill multiple functions related to breathing, protection and phonation. They develop at the head and trunk interface through a sequence of morphogenetic events that require precise temporo-spatial coordination. We are beginning to understand some of the molecular and cellular mechanisms that underlie critical processes such as specification of the laryngeal field, epithelial lamina formation and recanalization as well as the development and differentiation of mesenchymal cell populations. Nevertheless, many gaps remain in our knowledge, the filling of which is essential for understanding congenital laryngeal disorders and the evaluation and treatment approaches in human patients. This review highlights recent advances in our understanding of the laryngeal embryogenesis. Proposed genes and signaling pathways that are critical for the laryngeal development have a potential to be harnessed in the field of regenerative medicine.

"Innocent" arytenoid adduction asymmetry: An etiological survey.

PURPOSE: To estimate the incidence of "innocent" arytenoid adduction asymmetry (AAA) among patients presenting at a laryngology clinic, identify its association with demographic characteristics, symptomatology and various clinical/pathological conditions and thereby determine its clinical significance. METHODS: A prospective comparative observational clinical study was conducted. Group 1 included patients presenting at the Department of Laryngology, identified with a primary diagnosis and coexisting "innocent" AAA i.e., an overriding arytenoid with normal vocal fold mobility on laryngoscopy. Group 2 included an equal number of randomly selected patients fulfilling the same criteria, without AAA. Demographic and clinical details were recorded and analyzed. RESULTS: 110 cases were included in each group. The incidence of innocent AAA was 12.7%. Males were predominant in both Groups, with the gender difference significant in Group 1. Patients in Group 1 were significantly younger than in Group 2. Professional voice users, namely singers, were significantly greater in Group 1. Symptoms associated with Group 1 (i.e. AAA) were high pitch strain while singing (p = 0.01) and unilateral throat pain (p = 0.01), and the associated diagnoses were Singing Voice Dysphonia (p = 0.005), Vocal Process Granuloma (p = 0.04) and Ventricular Band Dysphonia (p = 0.047). As a definitive diagnosis was made in all patients, the presenting complaints were not attributed to AAA. Right sided preponderance of AAA was significant. Among the diagnoses with a laterality (e.g. vocal process granuloma), AAA was observed contralateral to the pathology in 70.7% and ipsilaterally in 29.3% (p = 0.0058). CONCLUSION: Innocent AAA is common among males in the 3rd-4th decades, in singers among professional voice users, and in those with the muscle tension dysphonia spectrum and vocal process granuloma, thereby suggesting that it is an acquired habit/response to greater vocal demand. The observation of AAA contralateral to laryngeal lesions, highlights its compensatory nature, attempting to optimize glottic closure.

Effects of hyaluronic acid-collagen nanofibers on early wound healing in vocal cord trauma.

BACKGROUND: Vocal cord scarring is the most crucial obstacle in voice quality after surgery. This study aimed to evaluate the effectiveness of hyaluronic acid (HA)-collagen nanofibers on the healing of vocal cords after surgical trauma. METHOD: Right vocal cords of 12 New Zealand white rabbits were traumatized, and the experimental group was received 1.08 mg/75 ml topical HA-collagen nanofiber (Gelfix® spray) for 3 days. Three animals in each group were sacrificed on the 7th day, and the remaining of the animals were sacrificed on the 21st day. The laryngeal specimens in the experimental and control groups were examined histopathologically. RESULT: The 7th-day H&E staining evaluation revealed pink, dense, and thin collagen fibers. Besides, the collagen content was scattered and irregular in the experimental group. The 21st-day assessment showed that the collagen bundles in the granulation tissue were almost with the same formation in both of the groups. Masson Trichrome staining on the 7th day of the study showed that the collagen fiber bundles were less frequent in the control group than the experimental group. The 7th-day Van Gieson staining analysis showed that the pattern of reticular fibers was more regular with the parallel formation in the experimental group than the control group. CONCLUSION: HA-collagen nanofiber can be used in diseases that impair voice quality due to the thickening of the lamina propria layer in the vocal cord and impaired viscoelasticity due to fibrosis after tissue trauma.

Short-term outcome of transcutaneous glucocorticoid injection for laryngeal contact granuloma in females.

OBJECTIVE: To evaluate the short-term efficacy of transcutaneous glucocorticoid injection for laryngeal contact granuloma in females. METHODS: A total of 14 female patients with laryngeal contact granuloma treated in our outpatient department from November 2017 to January 2020 were included in the study. Inspiratory-phase laryngoscopy images were collected before treatment and 1 month after each injection, and the lesion size was measured and evaluated with ImageJ software. RESULTS: Two patients achieved complete remission after one injection, with a percent reduction of 100%. After two injections, 4 patients achieved complete remission, with a percent reduction ranging from 96% to 100%. After 3 injections, 4 patients achieved complete remission (including one patient with bilateral lesions), and the percent reduction ranged from 95% to 100%. Three patients achieved incomplete remission, with a percent reduction of 46%, 55%, and 81%, respectively. In one case, there was no remission, and the granuloma increased in size after treatment. CONCLUSION: In women with laryngeal contact granuloma, transcutaneous glucocorticoid injection therapy can quickly resolve the granuloma in a short period.

Intra-operative recovery of preoperative vocal cord paralysis during hemithyroidectomy for benign thyroid disease: case report and review of the literature.

INTRODUCTION: Multinodular goiter associated with preoperative vocal cord palsy is usually indicative of invasive thyroid malignancy. However, benign thyroid disease may also lead to vocal cord paralysis. CASE REPORT: We present a case of a 63-year old woman with a two-month history of hoarseness, loss of vocal pitch, difficulties with swallowing and shortness of breath. Preoperative flexible fiberoptic laryngoscopy showed a left vocal cord paralysis. Left hemithyroidectomy with isthmectomy under intraoperative neuromonitoring for multinodular goiter was performed. Intra-operatively, both ipsilateral recurrent laryngeal nerve (RLN) and vagal nerve (VN) were identified and preserved. Follow-up laryngoscopy 5 weeks postoperatively showed complete recovery of the left vocal cord movement. DISCUSSION: Intuitively, surgeons may assume that preservation of a palsied RLN in patients with preexisting vocal cord paralysis is not meaningful. However, patients with RLN palsy associated with benign thyroid disease can experience full recovery after surgery. CONCLUSION: Multinodular goiter associated with preoperative vocal cord paralysis should be managed with extreme caution and use of intra-operative neuromonitoring. The existing probability of intra-operative recovery of a preoperative RLN palsy underlines the importance of preserving the affected RLN during surgery for benign thyroid disease.

[Molecular laryngology : A new chapter in the understanding of laryngeal diseases]. / Molekulare Laryngologie : Ein neues Kapitel im Verständnis laryngealer Erkrankungen.

BACKGROUND: Despite considerable advances in laryngological research, there is still a plethora of (benign) vocal fold pathologies that cannot be treated causally. This is due to the limited accessibility and sensitive microarchitecture of the vocal folds, which cannot be investigated at a cellular level. Consequently, current pathophysiological knowledge is frequently based on macroscopic findings. The impact of interventions is mainly evaluated endoscopically or via indirect diagnostic methods. OBJECTIVE: The aim of this article is to discuss state-of-the-art biotechnological methods used in laryngological research, illustrated by practical examples. RESULTS: In recent years, animal and in vitro experiments have significantly contributed to a continuous expansion of knowledge in this field, particularly regarding vocal fold inflammation and scar formation. Vocal fold fibroblasts, the most important cellular component of the lamina propria, can be accredited a central role in these processes. CONCLUSION: Our knowledge regarding macroanatomy and macropathophysiology of several pathologies has increased considerably in recent years. In vitro trials have shown, e.g., that vocal fold fibroblasts in an inflammatory setting secrete less profibrotic and proinflammatory cytokines when exposed to vibration. Early vocal exercises after surgical interventions on the vocal folds may therefore promote better wound healing and consequently improved phonation. Research in molecular laryngology should create a solid basis of knowledge for subsequent clinical studies.

Diagnosis of recurrent laryngeal nerve paralysis following esophagectomy by evaluating movement of the vocal cords and arytenoid cartilages using ultrasonography.

Advancements in thoracoscopic surgery have provided us with a deeper anatomical understanding of recurrent laryngeal nerve paralysis (RLNP), which is likely to occur after lymph node dissection. Taking a novel approach to researching the diagnosis of RLNP, we evaluated movement of the vocal cords and arytenoid cartilages using ultrasonography in patients who underwent thoracoscopic esophagectomy. RLNP occurred in six of the 24 patient cohort. The rate of hoarseness and difficulty in discharging sputum was significantly higher in the paralyzed group than in the non-paralyzed group. The diagnostic accuracy of RLNP by ultrasonography had a sensitivity of 83.3% (5/6), a specificity of 88.8% (16/18), a false positive rate of 5.6% (1/18), and a false negative rate of 0% (0/6). Although it is not completely accurate, our findings indicate that ultrasonography is quite effective for diagnosing RLNP, more so in combination with clinical symptoms. Ultrasonography may also be effective for identifying patients who are amenable to laryngoscopy for diagnosing RLNP, or for evaluating the recovery status of nerve paralysis.

Life Threatening Delayed Complication of Botulinum Toxin Injection for Treatment of Spasmodic Dysphonia.

Spasmodic dysphonia is a primary task specific focal dystonia affecting the laryngeal muscles during speech. Most medical and surgical approaches to treatment of spasmodic dysphonia are aimed at the denervation of the laryngeal muscles to block symptom expression in the voice. The standard of care for the adductor form of spasmodic dysphonia is botulinum toxin chemodenervation. The common side effects of treatment with Botox are excessive breathiness and aspiration of fluids. We present the report of a delayed presentation of upper airway obstruction due to a complete vocal cords adduction requiring intubation ten days post Botox injection for the adductor form of spasmodic dysphonia. This presentation may be preceded by a change in voice, productive cough, shortness of breath, or odynophagia. We would recommend supportive treatment in an Intensive Care Unit and close liaison with the otolaryngology team for the management of this complication. Acute upper airway obstruction requiring tracheal intubation is a delayed complication of botulinum toxin administration in the adductor form of spasmodic dysphonia.

Computational analysis of six optical coherence tomography systems for vocal fold imaging: A comparison study.

OBJECTIVES: There have been many advancements in laryngeal imaging using optical coherence tomography (OCT), with varying system design and probes for use in research, office, and operating room settings. We evaluated the performance of six distinct OCT systems in imaging porcine vocal folds (cords) using computational image processing and segmentation. METHODS: Porcine vocal folds were scanned using six OCT systems. Imaging system and probe performance were quantitatively assessed for signal penetration, layer differentiation, and epithelium (EP) measurement. Fitted exponential decay curves with corresponding α constant and intensity thresholding segmentation were utilized to quantify the aforementioned parameters. RESULTS: The smallest average α constant and deepest signal penetration was of the SS-OCT 1700 nm 90 kHz microscope system (α = -1.74), followed by the SS-OCT 1310 nm 200 kHz VCSEL microscope system (α = -1.99), and SS-OCT 1310 nm 50 kHz rigid forward viewing endoscope system (α = -2.23). The EP was not readily visualized for three out of six systems, but was detected using automated segmentation. Average EP thickness (mean ± SD) was calculated as 55.79 ± 31.86 µm which agrees favorably with previous literature. CONCLUSION: Comparisons of OCT systems are challenging, as they encompass different probe design, optical path, and lasers, depending on application. Practical evaluation of different systems using computer based quantitative image processing and segmentation revealed basic, constructive information, such as EP measurements. To further validate the comparisons of system performance with clinical usability, in vivo human laryngeal imaging will be conducted. Further development of automated image processing and segmentation can be useful in rapid analysis of information. Lasers Surg. Med. 51:412-422, 2019. © 2019 Wiley Periodicals, Inc.

An Unusual Cause of Failed Tracheal Decannulation-A Case Report.

Failure of decannulation may occur due to unexpected upper airway problems. However, the presence of a membrane in between the vocal cords is usually rare. We report a case of a 46-year-old female, who presented with focal seizures and progressed to status epilepticus. She was put on a mechanical ventilator because of hypoxic arrest. As she required prolonged ventilatory support, tracheostomy and gradual weaning from ventilator support to T-piece was done. Following stable hemodynamics, decannulation trial was attempted which failed. Subsequently, bronchoscopy was done to assess the upper airway. It revealed a thick membrane in between the vocal cords. Further examination with an indirect laryngoscope under general anesthesia confirmed the findings, and the membrance was excised. Decannulation was successful the very following day and the patient was discharged with stable hemodynamics. HOW TO CITE THIS ARTICLE: Kambhampati S, Lavanya K. An Unusual Cause of Failed Tracheal Decannulation-A Case Report. Indian J Crit Care Med 2019;23(8):378-379.