Postoperative sore throat and subglottic injury after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score: a randomized controlled trial.

BACKGROUND: A tracheal tube stylet can be used to assist successful tracheal intubation, especially during videolaryngoscopic intubation because videolaryngoscopes with a Macintosh-type blade such as McGrath® MAC videolaryngoscope have more acute angle than conventional Macintosh laryngoscope. However, the use of a stylet during tracheal intubation can raise concerns about stylet-induced postoperative airway complications, such as sore throat, subglottic injury, and hoarseness. In this study, we compared the incidence of postoperative airway complications after McGrath® MAC videolaryngoscopic intubation with versus without a stylet in patients with a high Mallampati score. METHODS: In 104 patients with Mallampati score III or IV and who were scheduled for lumbar or thoracic spine surgery, McGrath® MAC videolaryngoscopic intubation was performed either with a stylet (group S, n = 52) or without a stylet (group N, n = 52). The primary outcome measure was the incidences of sore throat evaluated at 1 and 24 h postoperatively. Secondary outcome measures were the incidences of subglottic injury and postoperative hoarseness. RESULTS: The incidence of CL grade III in group S and N was 3.8 and 5.8%, respectively. No patient showed CL grade IV. The incidences of sore throat at 1 (26.9 vs 19.2%, P = 0.485) and 24 h (17.3 vs 13.5%, P = 0.786, respectively) postoperatively were not significantly different between the group S and N. However, the incidence of subglottic injury was significantly higher in the group S, compared with the group N (65.4 vs 42.3%, P = 0.030). The incidence of postoperative hoarseness did not differ significantly between the two groups. CONCLUSIONS: The use of a stylet during McGrath® MAC videolaryngoscopic intubation did not have a significant impact on the incidence of postoperative sore throat in patients with a high Mallampati score. Avoiding the use of a stylet during intubation with McGrath® MAC videolaryngoscope may reduce the incidence of subglottic injury in such patients. TRIAL REGISTRATION: Clinical Research Information Service (identifier: KCT0002427 , date of registration: June 12, 2017).

Demographic and Symptomatic Features of Voice Disorders and Their Potential Application in Classification Using Machine Learning Algorithms.

BACKGROUND: Studies have used questionnaires of dysphonic symptoms to screen voice disorders. This study investigated whether the differential presentation of demographic and symptomatic features can be applied to computerized classification. METHODS: We recruited 100 patients with glottic neoplasm, 508 with phonotraumatic lesions, and 153 with unilateral vocal palsy. Statistical analyses revealed significantly different distributions of demographic and symptomatic variables. Machine learning algorithms, including decision tree, linear discriminant analysis, K-nearest neighbors, support vector machine, and artificial neural network, were applied to classify voice disorders. RESULTS: The results showed that demographic features were more effective for detecting neoplastic and phonotraumatic lesions, whereas symptoms were useful for detecting vocal palsy. When combining demographic and symptomatic variables, the artificial neural network achieved the highest accuracy of 83 ± 1.58%, whereas the accuracy achieved by other algorithms ranged from 74 to 82.6%. Decision tree analyses revealed that sex, age, smoking status, sudden onset of dysphonia, and 10-item voice handicap index scores were significant characteristics for classification. CONCLUSION: This study demonstrated a significant difference in demographic and symptomatic features between glottic neoplasm, phonotraumatic lesions, and vocal palsy. These features may facilitate automatic classification of voice disorders through machine learning algorithms.

Difficult tracheal tube passage and subglottic airway injury during intubation with the GlideScope® videolaryngoscope: a randomised, controlled comparison of three tracheal tubes.

Difficulty during placement of the tracheal tube is a known problem when intubating with the GlideScope® , which may lead to subglottic airway injury. This randomised, controlled clinical trial was designed to compare the resistance to passage of PVC (polyvinyl chloride), reinforced or BlockBuster tracheal tubes during intubation with the GlideScope. Secondary outcomes included the time taken to intubate and assessment of subglottic airway injury. One-hundred and seventy-seven patients were included in the data analysis. There was difficult tracheal tube passage (moderate or severe resistance) in 15 (21.4%) patients using the PVC tube compared with 4 (7.4%) and 1 (1.9%) using the reinforced and BlockBuster tubes, respectively (p = 0.003 for PVC vs. BlockBuster). The median (IQR [range]) time taken to intubate was 35 (27-45 [15-115]) s, 25 (20-27 [15-110]) s and 25 (22-30 [16-90]) s, respectively, (p < 0.001 for PVC vs. reinforced as well as PVC vs. BlockBuster). Subglottic airway injury, assessed using a fibreoptic bronchoscope after extubation, was higher with the PVC tube (p < 0.001) and the reinforced tube (p = 0.012) compared with the BlockBuster tube. We conclude that the BlockBuster tracheal tube is a better choice for orotracheal intubation with the GlideScope than PVC or reinforced tubes.

Conservative management of laryngeal dog bite.

BACKGROUND AND AIMS: Dog bites represent an important public health issue, causing injuries from trivial to fatal. The true incidence is unknown due to the lack of national and local reporting system. School children, mostly male, are more commonly affected with the majority of injuries occurring in the head and neck area, followed by the limbs and trunk. METHODS: The conservative management of a 6-year-old girl who sustained a fracture of her laryngeal structure from an attack by her neighbours' dog is described. Only a 1 cm visible puncture wound in the midline of her neck with air escaping through the wound was seen at presentation. RESULTS: Ten days were spent in hospital including the first four in intubated Paediatric Intensive Care Unit. Initial microlaryngoscopy and bronchoscopy (MLB) showed a swelling in the right anterior subglottis not reducible by manipulation. She was re-intubated with progressively larger naso-tracheal tube until the fracture was fully reduced on her 3rd MLB. Three months post-injury, there is no evidence of airway narrowing. CONCLUSION: The literature advocates early surgical management of laryngeal trauma including dog bites. Conservative management of laryngeal fracture from a dog bite is feasible and associated with a good outcome and no long-term sequela.

Posterior Glottic Injury Following Prolonged Intubation in COVID-19 Patients.

OBJECTIVE: The objective of this study was to characterize the risk factors for posterior glottic injury (PGI) in patients with coronavirus disease 2019 (COVID-19) who underwent prolonged intubation. STUDY DESIGN: This was a case-control study designed to assess the risk factors associated with development of PGI in COVID-19 patients who underwent prolonged intubation. SETTING: This single-center study was conducted at a tertiary care academic hospital in a metropolitan area. METHODS: We retrospectively reviewed patients who underwent prolonged intubation (≥7 days) for COVID-19 and compared those with PGI to those without. Patient demographics, comorbidities, and intubation characteristics were compared. Factors associated with PGI development among COVID-19 patients were assessed using multivariate regression. RESULTS: We identified 56 patients who presented with PGI following prolonged intubation for COVID-19 and 60 control patients who underwent prolonged intubation for COVID-19 but did not develop PGI. On univariate analyses, the number of reintubations due to failed extubation efforts was significantly associated with development of PGI (odds ratio [OR], 2.9; 95% CI, 1.4-6.2). On multivariate analyses, patients with cardiovascular disease (OR, 3.3; 95% CI, 1.2-9.0); non-COVID-19 respiratory illnesses, which included obstructive sleep apnea and asthma (OR, 5.9; 95% CI, 2.0-17.8); and diabetes mellitus (OR, 11.6; 95% CI, 3.7-36.6) were more likely to develop PGI. CONCLUSION: Our results represent the largest case-control study investigating risk factors for PGI in the setting of prolonged intubation specific to COVID-19. Our study suggests a significant role of comorbidities associated with poor wound healing with development of PGI.

Posterior glottic diastasis: mechanically deceptive and often overlooked.

Dysphonia secondary to posterior glottic aerodynamic incompetence can often be recognizable acoustically, but difficult to document visually. This mechanical impairment in posterior glottic closure is the result of injury caused by airway instrumentation. The difficulty of recognition of this entity is due to posterior supraglottic soft tissue that obscures the complete view during posterior glottic adduction, the lack of a structural organization of the cricoarytenoid region injury that leads to this disorder, and the lack of nomenclature. A retrospective assessment was done on 3 patients who underwent surgical reconstruction to correct posterior phonatory incompetence subsequent to laryngotracheal intubation. All 3 had sustained an injury to the cricoarytenoid joints, and 2 of the 3 had undergone paraglottic space medialization laryngoplasty that failed to solve the posterior glottic insufficiency. New procedures were designed and performed in these patients to correct the posterior glottic incompetence and are described: laryngofissure and partial posterior cricoid resection, endoscopic pharyngoepiglottic-aryepiglottic fold advancement-rotation flap with interarytenoid interposition, and interarytenoid submucosal implant augmentation. Although the academic literature is replete with reports describing stenosis resulting from impaired cricoarytenoid joint abduction, the term glottic diastasis provides nomenclature for the inability to normally adduct the arytenoid cartilages. The initial experience with surgical reconstruction is preliminary, but encouraging.

Characterization of Fibroblasts in Iatrogenic Laryngotracheal Stenosis and Type II Diabetes Mellitus.

OBJECTIVES: Iatrogenic laryngotracheal stenosis (iLTS) is the pathological narrowing of the glottis, subglottis, and/or trachea due to scar tissue. Patients with type 2 diabetes mellitus (T2DM) are over 8 times more likely to develop iLTS and represent 26% to 53% of all iLTS patients. In this investigation, we compared iLTS scar-derived fibroblasts in patients with and without T2DM. STUDY DESIGN: Controlled ex vivo study. METHODS: iLTS scar fibroblasts were isolated and cultured from subglottic scar biopsies in iLTS patients diagnosed with or without type 2 diabetes (non-T2DM). Fibroblast proliferation, fibrosis-related gene expression, and metabolic utilization of oxidative phosphorylation (OXPHOS) and glycolysis were assessed. Contractility was measured using a collagen-based assay. Metabolically targeted drugs (metformin, phenformin, amobarbital) were tested, and changes in fibrosis-related gene expression, collagen protein, and contractility were evaluated. RESULTS: Compared to non-T2DM, T2DM iLTS scar fibroblasts had increased α-smooth muscle actin (αSMA) expression (8.2× increased, P = .020), increased contractility (mean 71.4 ± 4.3% vs. 51.7 ± 16% Δ area × 90 minute-1 , P = .016), and reduced proliferation (1.9× reduction at 5 days, P < .01). Collagen 1 (COL1) protein was significantly higher in the T2DM group (mean 2.06 ± 0.19 vs. 0.74 ±.44 COL1/total protein [pg/µg], P = .036). T2DM iLTS scar fibroblasts had increased measures of OXPHOS, including basal respiration (mean 86.7 vs. 31.5 pmol/minute/10 µg protein, P = .016) and adenosine triphosphate (ATP) generation (mean 97.5 vs. 25.7 pmol/minute/10 µg protein, P = .047) compared to non-T2DM fibroblasts. Amobarbital reduced cellular contractility; decreased collagen protein; and decreased expression of αSMA, COL1, and fibronectin. Metformin and phenformin did not significantly affect fibrosis-related gene expression. CONCLUSION: T2DM iLTS scar fibroblasts demonstrate a myofibroblast phenotype and greater contractility compared to non-T2DM. Their bioenergetic preference for OXPHOS drives their increased contractility, which is selectively targeted by amobarbital. LEVEL OF EVIDENCE: NA Laryngoscope, 131:1570-1577, 2021.

A prospective randomized trial comparing supraglottic airways for flexible bronchoscopy in children.

OBJECTIVE: A prospective randomized, controlled trial was conducted comparing supraglottic airways (SGA) for flexible bronchoscopy in 100 children. BACKGROUND: Pediatric flexible bronchoscopy is commonly performed using a SGA as both a ventilation device and a conduit for flexible bronchoscopy. We observed that some disposable SGAs were associated with increased resistance to bronchoscope manipulation compared to the LMA Classic (cLMA). METHODS: We compared the cLMA to the Ambu Aura Once, Portex Soft Seal, Boss Systems disposable silicone laryngeal mask, and LMA Unique. We recorded the subjective resistance of the bronchoscope manipulation within the SGA by linear analog score and measured the time to insert the bronchoscope from the proximal end of the SGA to the right upper lobe. We also scored the view of the larynx through the bronchoscope and measured SGA cuff pressures. RESULTS: Resistance to bronchoscope manipulation during pediatric flexible bronchoscopy was higher using polyvinyl chloride (PVC) disposable SGAs (Ambu, Unique, and Portex) than the silicone re-usable cLMA (P < 0.0001). The Unique and Ambu laryngeal masks were clinically inferior to the cLMA at all levels of the airway (P < 0.0001). The Portex Soft Seal was not different above the larynx but was significantly statistically inferior at (P < 0.04) and below the larynx (P < 0.006) and inferior overall (P < 0.007). Boss Systems single-use laryngeal mask was as effective as the cLMA. CONCLUSION: In this trial, PVC single-use laryngeal masks were inferior to the silicone cLMA and Boss Systems laryngeal masks for flexible bronchoscopy in children.

[Laryngeal and pharyngeal actinomycosis]. / Aktinomykose im Bereich von Pharynx und Larynx.

Cervicofacial actinomycosis is an uncommon infection and in most cases odontogenic in origin. Pharyngeal and/or laryngeal lesions, usually occurring secondary to mucosal trauma, are very rare and may mimic a malignant tumor. In such cases, which represent less than 1% of all cases, the differential diagnosis with upper aerodigestive tract malignancy remains challenging. We report a case of actinomycosis in a 56-year-old male patient who presented with an extensive, centrally necrotic mass in the oropharynx, hypopharynx and larynx region suspected to be a tumor. The lesion was diagnosed 6 months following accidental ingestion of an ear of corn and ultimately proved to be cervicofacial actinomycosis. The clinical and pathological features and current aspects of the diagnosis and treatment of cervicofacial actinomycosis are discussed.

Total pharyngo-supraglottic separation following blunt neck trauma: a case report.

Blunt laryngeal trauma is a rare, potentially life-threatening event. A man suffered total pharyngosupraglottic separation following accidental strangling, when a long cloth hanging around his neck was tracked into a threshing machine. Difficulty maintaining the airway was the primary challenge since the laryngotracheal complex had collapsed into the mediastinum. The authors palpated the thyroid cartilage just above the sternal notch but could not identify the tracheal ring for tracheotomy. Injuries to the laryngotracheal complex are severe if there is such a complete separation. Early diagnosis and proper management reduce morbidity and mortality. The successful management of such a case is presented

Glottic Stenosis: An Anatomic Analysis and New Treatment With a Self-Retaining Interarytenoid Spring.

INTRODUCTION:: Endotracheal (ET) intubation is a common cause of acquired glottic stenosis. Severe cases often require an irreversible arytenoidectomy/cordectomy, which typically results in poor voice quality. Adult human cadaver larynges were studied to gain insights about ET tube-induced posterior glottic injuries, hoping to create a less invasive remedy. STUDY DESIGN:: Human cadaver investigation and case reports. METHODS:: Microlaryngeal assessments were done on 10 human cadaver larynges (5 men, 5 women) with and without ET tubes. After supracricoid soft tissue resection, measurements were obtained, including the distance between the outer diameter of the ET tube and the medial aspect of the cricoarytenoid joint facet. Additionally, measurements of the circumferential arc of differently sized ET tubes were made alongside both cricoarytenoid joint capsules. This information was used to design a silastic stent that would function as a self-retaining interarytenoid spring to treat posterior glottic stenosis in 5 patients. Four of 5 patients included in the clinical study were tracheotomy dependent, primarily because of glottic stenosis. The human surgical technique is described in detail. RESULTS:: The shortest distance between the outer diameter of the ET tube to the medial cricoid facet averaged 5.02 mm in men and 3.62 mm in women. On the basis of the diameter of the intralaryngeal component of the initially round stent, and the position of the cricoarytenoid joint facets, the interarytenoid spring would have a subtended arc between 110° and 175°. These data helped fashion parameters for modifying a conventional T-tube to form a new self-retaining silastic interarytenoid spring. The first 5 human cases have been successful, allowing effective tracheotomy tube decannulation and excellent voice quality. CONCLUSIONS:: The anatomic investigation herein provided key insights into ET tube-induced glottic stenosis and facilitated a new straightforward procedure to surgically improve the airway yet preserve excellent vocal function in patients with acquired glottic stenosis. Level of Evidence: NA.

Effects of halofuginone on fibrosis formation secondary to experimentally induced subglottic trauma.

OBJECTIVE: The aim of the study was to assess the antifibrotic effect of systemically applied halofuginone after subglottic injury. MATERIALS AND METHODS: After standardized trauma to subglottic area, rats were divided into two groups: a study group that received treatment and a control group that did not. The rats were treated with 0.1 mg/kg/day intraperitoneal halofuginone injection for 30 days. The larynx specimens were examined histopathologically under light microscope for epithelization, inflammation, necrosis, and fibrosis. RESULTS: The fibrosis indexes of the treated group were significantly less than those of the control group (P < .01). CONCLUSIONS: Systemically applied halofuginone hydrobromide decreases fibrosis/scar tissue formation secondary to experimentally induced acute subglottic trauma.

Graded carbon dioxide laser-induced subglottic injury in the rabbit model.

OBJECTIVE: To conduct an endoscopic and histologic analysis of the subglottic effects of various carbon dioxide laser-induced injuries in the rabbit model. DESIGN: Animals were assigned to either a control (cricothyroidotomy only) group or 4 (cricothyroidotomy and posterior subglottic laser) groups that were injured using varying systematically controlled carbon dioxide laser power exposures (5 W, 8 W, and 12 W), with durations of 2 or 4 seconds, and surface area exposures (25% or 40%). SUBJECTS: Twenty-seven New Zealand white rabbits. INTERVENTIONS: The subglottis was approached via cricothyroidotomy. Control airways were immediately closed, while injured airways were subjected to graded carbon dioxide laser exposures prior to closure. Airways were endoscopically monitored preoperatively, immediately postoperatively, and on postoperative days 1, 7, 14, and 21, after which the animals were humanely killed and subglottic tissue harvested for histological evaluation. RESULTS: Clinical observation revealed no significantly obstructive (acute) stenosis during the duration of the study. Endoscopic visualization revealed the formation of posterior subglottic scarring. Histological analysis of the mucosa revealed that use of carbon dioxide laser resulted in a statistically significant (unpaired, 2-tailed t test, P<.05) proportional thickening of the lamina propria layer, without significant changes in the epithelial and cartilaginous layers. In addition, mucosal blood vessel size increased proportional to the power of the laser delivered to the area (P<.05). CONCLUSIONS: Carbon dioxide laser-induced injury to the subglottis caused localized scarring, lamina propria thickening, and increased vascularity, which resolved with time and was not associated with significant airway obstruction. This model describes a systematic, controlled, and reproducible method of investigating subglottic injury.

Elucidating the role of interleukin 1beta and prostaglandin E2 in upper airway mucosal wound healing.

OBJECTIVES: To determine whether (1) inflammatory mediators IL-1beta (interleukin 1beta) and prostaglandin E2 (PGE2) in mucosal secretions correlate with subglottic mucosal injury; and (2) mucosal fibroblasts contribute to PGE2 production during mucosal healing. DESIGN: The subglottic mucosa in rabbits was wounded by means of varied carbon dioxide laser power and duration. Subglottic fibroblasts were exposed to IL-1beta and assayed for production of PGE2. SUBJECTS: Thirty-eight New Zealand white rabbits were used. Fibroblasts from normal and pathologic human subglottic tissues were grown in culture. INTERVENTIONS: Subglottic injury was established in 29 rabbits, and 9 rabbits were sham-wounded. Subglottic mucosal secretions were collected at baseline and days 1, 3, 7, 14, and 21 postoperatively and assayed for IL-1beta and PGE2 by enzyme-linked immunosorbent assay. Tissue was analyzed using quantitative polymerase chain reaction. Fibroblast cultures were exposed to IL-1beta and analyzed for PGE2 and its synthetic enzymes. RESULTS: Subglottic injury was associated with increased levels of IL-1beta and PGE2 in secretions. More extensive mucosal injury resulted in higher PGE2 levels at earlier times. Levels of IL-1beta were maximal after lesser damage. Expression of IL-beta and cyclo-oxygenase 2 was elevated after mucosal injury. Fibroblast treatment with IL-1beta resulted in translocation of nuclear factor kappaB, up-regulation of PGE2 synthetic enzymes, and increased production of endogenous PGE2. CONCLUSIONS: Mucosal injury is associated with up-regulation of inflammatory genes and parallel increases in secretion levels of IL-1beta and PGE2, key mediators of inflammation and healing. Subglottic mucosal fibroblasts are a potential source of inflammatory mediators after injury or other trauma.

Transcricothyroid Endoscopic Subglottic Surgery for Posterior Glottic Stenosis: A Case Report.

Posterior glottic stenosis (PGS) is a rare but life-threatening condition mostly caused by damage to the interarytenoid mucosa by an endotracheal tube. In surgical treatment of PGS, airway patency is prioritized, and the laryngeal functions involved in swallowing and phonation are considerably sacrificed. In the majority of cases, lateralization of a vocal fold or partial excision of a vocal fold and arytenoid cartilage results in glottal closure insufficiency and deterioration of phonatory function. We present the first report of transcricothyroid endoscopic subglottic surgery to treat a 46-year-old man with PGS who was intubated for 10 days. Postoperative hypofunction was not observed in the aerodynamic examination and acoustic analysis, and phonatory function has been maintained within normal limits.

Can mitomycin C really prevent airway stenosis?

BACKGROUND/OBJECTIVES: Mitomycin C (MMC) is used in the prevention of upper airway stenosis. However, the efficacy of MMC is still debatable, and the potential complications of MMC use have been scarcely reported. We evaluated the efficacy and early complications of MMC in a wound model of the subglottis. STUDY DESIGN: A randomized animal study. METHODS: Sixty rabbits underwent a full-thickness injury to the posterior subglottis by diode laser. The animals were randomly assigned to three groups according to the different topical treatments of MMC 0.4 or 10 mg/mL or saline alone for 5 minutes. Animals were killed at 4 weeks, and gross and histologic findings were compared among different groups and 10 age-matched, non-wound, normal controls. RESULTS: Thirty-two of the 60 (53%) animals died mainly of acute airway obstruction by necrotic debris, sloughs on, or cartilage collapse of the unhealed posterior subglottis during early weeks after wounding, higher in the MMC-treated animals (67%) than in the wound controls (25%) (P = .007). This resulted from the significant delay of wound healing in the MMC-treated groups compared with the wound controls (P = .012). The degree of subglottic stenosis was comparable among different groups (P > .8), although collagen deposition was significantly lower in the MMC-treated groups compared with the untreated controls (P = .036). CONCLUSIONS: There was a significant risk of acute airway obstruction from delayed wound healing in rabbits that received subglottic laser wounding and MMC treatment. This risk should be considered in the use of MMC in clinical practice.