Effects of 3D Airway Geometry on the Airflow of Adults with Cleft Lip and Palate and Obstructive Sleep Apnea: A Functional Imaging Study.

 Individuals with cleft lip and palate (CLP) are at a high risk of developing obstructive sleep apnea (OSA). Hypothetically, the severity of OSA might be associated with the morphology of the upper airway (UAW) and the characteristics of the airflow. Thus, the present study aimed to assess and compare, in adults with CLP and skeletal class-III discrepancy, with or without OSA, simulations of airflow resistance and pressure according to the geometrical characteristics of the UAW and cephalometric parameters.

Mucolytic treatment of chronic rhinosinusitis in a murine model of primary ciliary dyskinesia.

Genetic defects in motile cilia cause primary ciliary dyskinesia (PCD), a rare disease with no specific therapeutics. Individuals with PCD often have impaired fertility and laterality defects and universally suffer from upper and lower airway diseases. Chronic rhinosinusitis is a universal feature of PCD, and mucus accumulation and subsequent infections of the sinonasal cavity cause significant morbidity in individuals with PCD.

Updating the biologically based dose-response model for the nasal carcinogenicity of inhaled formaldehyde in the F344 rat.

Chronic inhalation of formaldehyde by F344 rats causes nasal squamous cell carcinoma (SCC). This outcome is well-characterized: including dose-response and time course data for SCC, mechanistic endpoints, and nasal dosimetry. Conolly et al.

Relative contributions of endogenous and exogenous formaldehyde to formation of deoxyguanosine monoadducts and DNA-protein crosslink adducts of DNA in rat nasal mucosa.

Understanding the dose-response for formaldehyde-induced nasal cancer in rats is complicated by (1) the uneven distribution of inhaled formaldehyde across the interior surface of the nasal cavity and, (2) the presence of endogenous formaldehyde (endoF) in the nasal mucosa. In this work, we used computational fluid dynamics (CFD) modeling to predict flux of inhaled (exogenous) formaldehyde (exogF) from air into tissue at the specific locations where DNA adducts were measured. Experimental work has identified DNA-protein crosslink (DPX) adducts due to exogF and deoxyguanosine (DG) adducts due to both exogF and endoF.

Anatomic Optical Coherence Tomography (aOCT) for Evaluation of the Internal Nasal Valve.

Objectives/hypothesis: To establish the utility of anatomic optical coherence tomography (aOCT) in evaluating internal nasal valve (INV).

Study Design: Anatomic specimen imaging study.

Methods: Fresh-harvested human specimen heads were evaluated using both computed tomography (CT) imaging as well as using aOCT.

Lung inflammation and simulated airway resistance in infants with cystic fibrosis.

Cystic fibrosis (CF) is characterized by small airway disease; but central airways may also be affected. We hypothesized that airway resistance estimated from computational fluid dynamic (CFD) methodology in infants with CF was higher than controls and that early airway inflammation in infants with CF is associated with airway resistance. Central airway models with a median of 51 bronchial outlets per model (interquartile range 46,56) were created from chest computed tomography scans of 18 infants with CF and 7 controls.

Radiologic Analysis of Balloon Sinuplasty in a Human Cadaver Model: Observed Effects on Sinonasal Anatomy.

Background: Balloon sinuplasty is increasingly used in the outpatient clinic for treatment of chronic rhinosinusitis, but radiologic analysis of its effects on sinonasal anatomy is largely uncharacterized in the known literature.

Objective: The purpose of this study is to examine the anatomic effects of balloon sinuplasty in a cadaveric model.

Methods: Five fresh cadaver heads underwent sequential endoscopic balloon dilation of maxillary ostia, frontal recess outflow tracts, and sphenoid ostia bilaterally by fellowship-trained rhinologists.

Numerical evaluation of spray position for improved nasal drug delivery.

Topical intra-nasal sprays are amongst the most commonly prescribed therapeutic options for sinonasal diseases in humans. However, inconsistency and ambiguity in instructions show a lack of definitive knowledge on best spray use techniques. In this study, we have identified a new usage strategy for nasal sprays available over-the-counter, that registers an average 8-fold improvement in topical delivery of drugs at diseased sites, when compared to prevalent spray techniques.

Nasal Airflow Changes With Bioabsorbable Implant, Butterfly, and Spreader Grafts.

Objectives/hypothesis: Internal nasal valve compromise is a major cause of nasal obstruction, with a growing number of ways to treat this condition. In this study, we compared the effects of butterfly graft, spreader graft, and the bioabsorbable nasal implant on nasal airflow resistance.

Study Design: Cadaver study.

Virtual septoplasty: a method to predict surgical outcomes for patients with nasal airway obstruction.

Purpose: A deviated nasal septum is the most common etiology for nasal airway obstruction (NAO), and septoplasty is the most common surgical procedure performed by ear-nose-throat surgeons in adults. However, quantitative criteria are rarely adopted to select patients for surgery, which may explain why up to 50% of patients report persistent or recurrent symptoms of nasal obstruction postoperatively. This study reports a systematic virtual surgery method to identify patients who may benefit from septoplasty.

Utility of endoscopic anatomical optical coherence tomography in functional rhinoplasty.

Objective measurement of the nasal valve region is valuable for the assessment of functional rhinoplasty surgical outcomes. Anatomical optical coherence tomography (aOCT) is an imaging modality that may be used to obtain real-time, quantitative, and volumetric scans of the nasal airway. We aim to evaluate if volumetric aOCT imaging is useful for the examination of the nasal valve region before and after functional rhinoplasty procedures.

Intranasal Corticosteroids: Patient Administration Angles and Impact of Education.

Introduction: Intranasal corticosteroids sprays (INCS) are first line treatment for allergic rhinitis and are frequently used for chronic rhinosinusitis. Improperly aiming INCS increases the risk of epistaxis and may decrease the efficacy of the medication. The goal of this study was to determine how patients position INCS for drug delivery and if verbal or written instructions improve their positioning.

Reduced pharyngeal dimensions and obstructive sleep apnea in adults with cleft lip/palate and Class III malocclusion.

: To three-dimensionally evaluate the upper airway of individuals with cleft lip and palate (CLP) and Class III malocclusion and the occurrence of obstructive sleep apnea (OSA).: Twenty-one CLP individuals with Class III malocclusion, 20-29 years of age, who underwent computed tomography for orthognathic surgery planning, were prospectively evaluated. All participants underwent polysomnography, and the apnea-hypopnea index ≥ 5 events/hour was considered indicative of OSA.

Normative ranges of nasal airflow variables in healthy adults.

Purpose: Virtual surgery planning based on computational fluid dynamics (CFD) simulations of nasal airflow has the potential to improve surgical outcomes for patients with nasal airway obstruction (NAO). Virtual surgery planning requires normative ranges of airflow variables, but few studies to date have quantified inter-individual variability of nasal airflow among healthy subjects. This study reports CFD simulations of nasal airflow in 47 healthy adults.

Impact of endoscopic craniofacial resection on simulated nasal airflow and heat transport.

Background: Endoscopic craniofacial resections (CFR) are performed for extensive anterior skull base lesions. This surgery involves removal of multiple intranasal structures, potentially leading to empty nose syndrome (ENS). However, many patients remain asymptomatic postoperatively.

Comparative study of simulated nebulized and spray particle deposition in chronic rhinosinusitis patients.

Background: Topical intranasal drugs are widely prescribed for chronic rhinosinusitis (CRS), although delivery can vary with device type and droplet size. The study objective was to compare nebulized and sprayed droplet deposition in the paranasal sinuses and ostiomeatal complex (OMC) across multiple droplet sizes in CRS patients using computational fluid dynamics (CFD).

Methods: Three-dimensional models of sinonasal cavities were constructed from computed tomography (CT) scans of 3 subjects with CRS refractory to medical therapy using imaging software.

A computational fluid dynamics analysis of the effects of size and shape of anterior nasal septal perforations.

Background: Nasal septal perforations (NSPs) often cause bleeding, crusting, obstruction, and/or whistling. The objective was to analyze the impact of anterior NSP size and shape on nasal physiology using computational fluid dynamics (CFD).

Methods: A 3-dimensional model of the nasal cavity was constructed from a radiologically normal CT scan using imaging software.

A hierarchical stepwise approach to evaluate nasal patency after virtual surgery for nasal airway obstruction.

Background: Despite advances in medicine and expenditures associated in treatment of nasal airway obstruction, 25-50% of patients undergoing nasal surgeries complain of persistent obstructive symptoms. Our objective is to develop a "stepwise virtual surgery" method that optimizes surgical outcomes for treatment of nasal airway obstruction.

Methods: Pre-surgery radiographic images of two subjects with nasal airway obstruction were imported into Mimics imaging software package for three-dimension reconstruction of the airway.

An Interactive, Patient-Specific Virtual Surgical Planning System for Upper Airway Obstruction Treatments.

Upper airway obstructions leading todifficulty breathing are significant problems that often require surgery to improve patient quality of life. However, these surgeries often have poor outcomes with little symptom improvement. This paper outlines the design of an interactive, patient-specific virtual surgical planning system that uses patient CT scans to generate three-dimensional representations of the airways and incorporates computational fluid dynamics (CFD) as a part of the surgical planning process.

Geometric Validation of Continuous, Finely Sampled 3-D Reconstructions From aOCT and CT in Upper Airway Models.

Identification and treatment of obstructive airway disorders (OADs) are greatly aided by imaging of the geometry of the airway lumen. Anatomical optical coherence tomography (aOCT) is a promising high-speed and minimally invasive endoscopic imaging modality for providing micrometer-resolution scans of the upper airway. Resistance to airflow in OADs is directly caused by the reduction in luminal cross-sectional area (CSA).

Upper airway reconstruction using long-range optical coherence tomography: Effects of airway curvature on airflow resistance.

Objectives: Adenotonsillectomy (AT) is commonly used to treat upper airway obstruction in children, but selection of patients who will benefit most from AT is challenging. The need for diagnostic evaluation tools without sedation, radiation, or high costs has motivated the development of long-range optical coherence tomography (LR-OCT), providing real-time cross-sectional airway imaging during endoscopy. Since the endoscope channel location is not tracked in conventional LR-OCT, airway curvature must be estimated and may affect predicted airway resistance.

An updated analysis of respiratory tract cells at risk for formaldehyde carcinogenesis.

Study of the mode of action (MOA) relating exposure to a given chemical with an associated adverse outcome is an iterative process with each iteration driven by new understandings of the relevant biology. Here, we revisit a previously described, MOA-based clonal growth model of the human respiratory tract cancer risk associated with formaldehyde inhalation. Changes reflect a better understanding of populations of cells at risk of carcinogenic transformation in the pharynx, larynx and respiratory bronchiolar portions of the human respiratory tract and inclusion of basal cells in the pool of cells at risk.

Comparison of Airflow Between Spreader Grafts and Butterfly Grafts Using Computational Flow Dynamics in a Cadaveric Model.

Importance: Nasal valve compromise is a major cause of nasal obstruction, and multiple methods have been developed to address it.

Objective: To compare nasal airflow resistance, airflow partitioning, and mucosal cooling (heat flux) before and after 2 surgical interventions, butterfly and spreader graft placement, used to treat nasal valve compromise.

Design, Setting, And Participants: In this cadaveric tissue study, 4 fresh cadaveric heads underwent both spreader graft and butterfly graft surgical procedures in alternating sequence in March 2016.

On computational fluid dynamics models for sinonasal drug transport: Relevance of nozzle subtraction and nasal vestibular dilation.

Generating anatomically realistic 3-dimensional (3D) models of the human sinonasal cavity for numerical investigations of sprayed drug transport presents a host of methodological ambiguities. For example, subject-specific radiographic images used for 3D reconstructions typically exclude spray bottles. Subtracting a bottle contour from the 3D airspace and dilating the anterior nasal vestibule for nozzle placement augment the complexity of model building.

Relationship between degree of obstruction and airflow limitation in subglottic stenosis.

Objectives: Subglottic stenosis (SGS) is one of the most common airway disorders in pediatric patients. Currently, treatment decisions rely primarily on the Cotton-Myer scale, which classifies SGS severity based on percentage reduction in airspace cross-sectional area (CSA). However, the precise relationship between upper airway resistance and subglottic CSA is unknown.