An Aerosol Containment and Filtration Tent for Intubation During the COVID-19 Pandemic.

Background. Exposure to infectious droplets confers a high risk for infection transmission by the SARS-CoV-2 coronavirus. Aerosolizing procedures pose particular concern for increasing healthcare workers' (HCWs) risks of infection. Multiple creative personal protective equipment solutions have been utilized to minimize exposure to infectious particles; however, the overall benefit of many of these devices is limited by a number of factors. Methods. We designed an intubation tent consisting of a metal frame and a clear plastic sheet. The flexible walls of our tent offer increased maneuverability & access, although the efficacy in reducing risk of transmission to HCWs remained unclear. Using an atomizer, particle generator, and matchstick smoke, we simulated the generation of infectious respiratory droplets and aerosols and tested whether our device effectively decreased the concentration of these particles to which a provider might be exposed. Finally, we tested whether the addition of a vacuum fan fit with a high efficiency particulate air filter designed to evacuate contaminated air would influence particle concentrations inside and outside the tent. Results. Droplet dispersion tests with the tent in place showed that the simulated droplet distribution was limited to surfaces within the tent. Aerosol testing under a variety of circumstances consistently showed only a minor rise in particle concentration in the air outside the tent despite an initial peak of particle concentration during generation within. All testing demonstrated declining inside concentrations over time. Conclusions. Our simulations suggest our device has the potential to effectively decrease HCWs' exposure to infectious droplets and aerosolized viral particles.

Differences in laryngeal neurotrophic factor gene expression after recurrent laryngeal nerve and vagus nerve injuries.

OBJECTIVES: Recurrent laryngeal nerve (RLN) and vagus nerve (VN) injuries characteristically are followed by differing degrees of spontaneous reinnervation, yet laryngeal muscle neurotrophic factor (NF) expression profiles after RLN and VN injuries have not been well elucidated. This study's objective was to determine the relative changes in gene expression of 5 well-characterized NFs from laryngeal muscle after RLN or VN injuries in a time-dependent fashion, and demonstrate how these changes correspond with electromyography-assessed innervation status. METHODS: Thirty-six male rats underwent left RLN transection (12 rats), left VN transection (12 rats), or a sham procedure (12 rats). The primary outcomes included electromyographic assessment and laryngeal muscle NF expression quantification with reverse transcription polymerase chain reaction at 3 days and at 1 month. RESULTS: Electromyography at 3 days demonstrated electrical silence in the VN injury group, normal activity in the sham group, and nascent units with decreased recruitment in the RLN injury group. Reverse transcription polymerase chain reaction demonstrated that changes in NF gene expression from laryngeal muscles varied depending on the type of nerve injury (RLN or VN) and the specific laryngeal muscle (posterior cricoarytenoid or adductor) assessed. CONCLUSIONS: Laryngeal muscle NF expression profiles after cranial nerve X injury depend both upon the level of nerve injury and upon the muscles involved.

Local neurotoxins for prevention of laryngeal synkinesis after recurrent laryngeal nerve injury.

OBJECTIVES: Persistent vocal fold motion impairment after recurrent laryngeal nerve (RLN) injury is not characteristically due to absent reinnervation, but often results from spontaneous aberrant reinnervation (synkinesis). We administered local neurotoxins to selected laryngeal muscles after RLN injury to determine whether aberrant reinnervation could be selectively inhibited. METHODS: Unilateral RLN transection was performed in 24 male rats. Three weeks later, the denervated laryngeal adductor complex was injected with phenol, high- or low-dose vincristine sulfate (VNC), or saline solution. One month later, rat larynges were evaluated via videolaryngoscopy and laryngeal electromyography (LEMG). Larynges from euthanized animals were analyzed via immunofluorescent staining for the presence of reinnervation. RESULTS: One animal that received phenol and 3 animals that received high-dose VNC died of toxicity-related complications. In the surviving neurotoxin-treated animals, videolaryngoscopy showed increased lateralization of the immobile vocal fold. Only 1 phenol-injected rat had adductor complex motor recruitment (score of 3+) with LEMG. The other neurotoxin-treated animals demonstrated an absence of adductor complex reinnervation, with only insertional activity and fibrillations (no motor units/recruitment). Spontaneous ipsilateral abductor reinnervation was not affected by the adductor injections. CONCLUSIONS: Low-dose VNC injections appear to be relatively safe and effective in selectively inhibiting spontaneous aberrant reinnervation after RLN injury in an animal model.

The effects of nasal closure on quality of life in patients with hereditary hemorrhagic telangiectasia.

INTRODUCTION: Epistaxis is the most common symptom of hereditary hemorrhagic telangiectasia (HHT). Complete nasal closure is one of the treatment options for patients with severe, intractable epistaxis. In our experience, this surgery can be life changing in a positive sense; but many patients as well as their physicians understandably fear that such a procedure will diminish certain aspects of quality of life (QOL). METHODS: Case-control study of HHT patients treated at the University of Utah HHT Center of Excellence with and without nasal closure from January 2005 to January 2016. Patients were matched according to epistaxis severity. Each included patient was issued three surveys: Epistaxis Severity Score (ESS), the Pittsburg Sleep Quality Index (PSQI), and the Nasal Obstruction Symptom Evaluation (NOSE). RESULTS: After treatment, the mean PSQI and NOSE scores were not significantly different between the two groups. However, the mean ESS score in the nasal closure group was significantly lower at 1.10 compared to the severe epistaxis group with a mean score of 3.99 (P = .027). CONCLUSION: The results of this study demonstrate that nasal closure significantly improves epistaxis severity without having a significant effect on sleep or nasal obstruction as they relate to QOL. These findings suggest that nasal closure should be considered for HHT patients with chronic severe epistaxis. LEVEL OF EVIDENCE: 4.

A rapid, novel model of culturing cranial nerve X-derived motoneurons for screening trophic factor outgrowth response.

OBJECTIVES: After cranial nerve X (CN X) injury, vocal fold paralysis treatments currently face a myriad of obstacles in achieving non-synkinetic, functional reinnervation. Of particular therapeutic interest is the targeted administration of locally expressed biological neurotrophic factors (NFs). To date, a method to culture mature CN X motoneurons for NF responsiveness screening has not been described. METHODS: We herein present a novel method for establishing mature murine CN X motoneuron cultures, and use the model to test CN X motoneuron outgrowth response to individual and paired ascending concentrations of selected neurotrophic factors [glial cell-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF)]. RESULTS: Findings demonstrated low concentration (5 ng/ml) CNTF to have the greatest positive effect on motoneuron outgrowth, beyond that of both indivual NF and paired NF combinations, based on total neurite outgrowth [mean total neurite outgrowth = 445.7±84.45 µm in the (5 ng/ml) CNTF group versus 179.7±13.63 µm in saline controls (P<0.01)]. Paired treatments with CNTF/GDNF, and CNTF/BDNF promoted motoneuron branching at a variety of concentrations beyond saline controls, and paired GDNF/BDNF had inhibitory effects on motoneuron branching. DISCUSSION: Our described in vitro model of establishing mature CN X cultures allowed rapid screening for responsiveness to therapeutic NFs at a variety of concentrations and combinations. While the model ultimately may be used to investigate the molecular mechanisms of CN X motoneuron regeneration, the current study identified CNTF as a promising therapeutic candidate for the promotion of CN X outgrowth.

An experimental model to investigate initial tracheal anastomosis strength.

OBJECTIVES/HYPOTHESIS: Early anastomotic dehiscence is a devastating complication of segmental tracheal resection. Although wound healing, patient comorbidities, and anastomotic tension are all influential factors, there is a paucity of information available on initial tracheal stability after various tracheal anastomosis techniques in human tissue. STUDY DESIGN: Prospective cadaver study. METHODS: We present a novel, inexpensive pulley-based system to apply symmetric tension on the trachea in a longitudinal direction to the point of anastomotic dehiscence. The validity of this mechanism was confirmed with trials using incrementally increasing quantities of the same suture type. Twenty-four trials were then performed on 12 cadaver tracheas (six fresh and six preserved) to compare anastomotic strength with two commonly used suture materials (3-0 polyglactin [Vicryl] vs. 3-0 polydioxanone [PDS]). RESULTS: Validation studies demonstrated that the force increased appropriately with an increasing number of sutures tested. In the tracheal anastomoses, tracheal suture pull-through was the most common mechanism of dehiscence, regardless of suture type. No significant difference in anastomotic stability was detected between the fresh versus preserved cadaver tracheas. The mean anastomotic strength was slightly greater for Vicryl (179.9 N) when compared to PDS (161.5 N), but the difference did not reach significance (P = .207). CONCLUSIONS: We introduce an inexpensive tool for measuring initial tracheal anastomosis stability with human cadavers, which demonstrated no difference in the tracheal pull-through strength of Vicryl and PDS.

A new treatment option for laryngeal sensory neuropathy.

OBJECTIVES/HYPOTHESIS: Laryngeal sensory neuropathy (LSN) may produce a variety of symptoms, including chronic cough, globus sensation, odynophonia, and/or odynophagia. Etiologies are often iatrogenic, viral, or idiopathic, although the diagnosis is generally one of exclusion. The aim of this study is to introduce pregabalin (Lyrica, Pfizer Inc., New York, NY) as a potential new therapy for LSN. STUDY DESIGN: Retrospective clinical investigation. METHODS: : Charts were reviewed from 12 consecutive patients who were prescribed pregabalin for symptoms of LSN. Outcomes were reviewed by analyzing pre and post-treatment questionnaires asking patients to rate symptoms on a scale from 0 to 5. Adverse effects and evidence of drug tolerance were also recorded. RESULTS: Two patients did not tolerate pregabalin due to somnolence. Of those that tolerated the medication, mean pretreatment chief complaint symptom severity rating was 3.9, whereas mean post-treatment symptom rating was 1.2 after 1 month of pregabalin therapy. None of the patients developed drug tolerance effects over time. CONCLUSIONS: Pregabalin therapy appears to be an effective treatment option for laryngeal sensory neuropathy. Future prospective studies are needed to compare outcomes between pregabalin and other medications as treatments for LSN.

Localization of the muscular process for arytenoid adduction surgery.

OBJECTIVES/HYPOTHESIS: Arytenoid adduction (AA) surgery can be technically challenging, potentially limiting its utilization in general practice. Because AA often serves as an adjunct to thyroplasty type I (TTI) in the management of unilateral vocal fold paralysis, this study sought to define the anatomic position of the muscular process (MP) of the arytenoid cartilage in relation to the TTI window and other key thyroid cartilage landmarks, thereby facilitating a more efficient surgical approach. STUDY DESIGN: Cadaveric anatomic dissections. METHODS: Arytenoid MPs were identified bilaterally in eight cadavers for a total of 16 hemilarynges. The location of the MP was measured relative to the anteroinferior corner of the traditional TTI window and also relative to the roots of the superior and inferior cornua for comparison with other studies. RESULTS: : The muscular processes were located along an axial line extending posteriorly from the inferior border of the TTI window and parallel to the inferior border of the thyroid cartilage. In males, the mean distance to the MP was 26.9 mm from the anteroinferior corner of the window, whereas in females the mean distance was 18.9 mm. In all cases, the MP was inferior to the midpoint between the roots of the superior and inferior cornua (mean inferior offset = 2.7 mm). CONCLUSIONS: The TTI window can be used intraoperatively to help locate the arytenoid muscular process during arytenoid adduction surgery.