A national pediatric otolaryngology fellowship virtual dissection course using 3D printed simulators.

OBJECTIVE: Our objective was to create and evaluate a novel virtual platform dissection course to complement pediatric otolaryngology fellowship training in the setting of the COVID-19 pandemic. METHODS: A four-station, four-simulator virtual course was delivered to pediatric otolaryngology fellows virtually using teleconferencing software. The four stations consisted of microtia ear carving, airway graft carving, cleft lip repair, and cleft palate repair. Fellows were asked to complete pre- and post-course surveys to evaluate their procedural confidence, expertise, and attitudes towards the course structure. RESULTS: Statistical analysis of pre-course survey data showed fellows agreed that simulators should play an important part in surgical training (4.59 (0.62)); would like more options for training with simulators (4.31 (0.88)); and would like the option of saving their simulators for later reference (4.41 (0.85)). Fellows found the surgical simulators used in the course to be valuable as potential training tools (3.96 (0.96)), as competency or evaluation tools (3.91 (0.98)), and as rehearsal tools (4.06 (0.93)). Analysis showed a statistically significant improvement in overall surgical confidence in performing all four procedures. CONCLUSION: This virtual surgical dissection course demonstrates 3D printed surgical simulators can be utilized to teach fellows advanced surgical techniques in a low-risk, virtual environment. Virtual platforms are a viable, highly-rated option for surgical training in the setting of restricted in-person meetings and as a mechanism to increase access for fellows by reducing costs and travel requirements during unrestricted periods.

Toward a better understanding of nonoccupational sound exposures and associated health impacts: Methods of the Apple Hearing Study.

Globally, noise exposure from occupational and nonoccupational sources is common, and, as a result, noise-induced hearing loss affects tens of millions of people. Occupational noise exposures have been studied and regulated for decades, but nonoccupational sound exposures are not well understood. The nationwide Apple Hearing Study, launched using the Apple research app in November 2019 (Apple Inc., Cupertino, CA), is characterizing the levels at which participants listen to headphone audio content, as well as their listening habits. This paper describes the methods of the study, which collects data from several types of hearing tests and uses the Apple Watch noise app to measure environmental sound levels and cardiovascular metrics. Participants, all of whom have consented to participate and share their data, have already contributed nearly 300 × 106 h of sound measurements and 200 000 hearing assessments. The preliminary results indicate that environmental sound levels have been higher, on average, than headphone audio, about 10% of the participants have a diagnosed hearing loss, and nearly 20% of the participants have hearing difficulty. The study's analyses will promote understanding of the overall exposures to sound and associated impacts on hearing and cardiovascular health. This study also demonstrates the feasibility of collecting clinically relevant exposure and health data outside of traditional research settings.

Starting a medical 3D printing lab for otolaryngology-head and neck surgery collaboration.

OBJECTIVE: To evaluate the different strategies for developing and maintaining a 3-dimensional (3D) printing lab. METHODS: We evaluated two printing labs and compared their structure, integration, and production. RESULTS: While one lab was initiated by a clinician and the other by a technical expert, both labs followed a similar series of steps to develop their lab. Each identified a key clinical need, developed a collaborative team, found financial support, and discovered options for sustainability. CONCLUSIONS: While there is no correct path for developing a 3D printing lab, depending on the existing infrastructure and the clinical need, one may choose a certain initial structure for a lab while following a list of common necessary steps.

Evaluating Directional Dependency of Selective Laser Sintered Patient Specific Biodegradable Devices to Improve Predictive Modeling and Design Verification.

Additive manufacturing, or 3D printing, of the bioresorbable polymer [Formula: see text]-polycaprolactone (PCL) is an emerging tissue engineering solution addressing patient specific anatomies. Predictively modeling the mechanical behavior of 3D printed parts comprised of PCL improves the ability to develop patient specific devices that meet design requirements while reducing the testing of extraneous design variants and development time for emergency devices. Predicting mechanical behavior of 3D-printed devices is limited by the variability of effective material moduli that are determined in part by the 3D printing manufacturing process. Powder fusion methods, specifically laser sintering, are known to produce parts with internal porosity ultimately impacting the mechanical performance of printed devices. This study investigates the role of print direction and part size on the material and structural properties of laser sintered PCL parts. Solid PCL cylinders were printed in the XY (perpendicular to laser) and Z direction (parallel to laser), scanned using microcomputed tomography, and mechanically tested under compression. Compositional, structural, and functional properties of the printed parts were evaluated with differential scanning calorimetry, gel permeation chromatography, microcomputed tomography, and mechanical testing. Computational models of printed and scanned cylinders were fit to experimental data to derive effective moduli. Effective moduli were used to predict the mechanical behavior of splints used for emergency repair of severe tracheobronchomalacia. Laser sintering did not cause significant differences in polymer material properties compared to unmanufactured powder. Effective moduli (Eeff) were greater for larger part sizes (p < 0.01) and for parts oriented in the XY direction compared to the Z direction (p < 0.001). These dependencies were congruent with the differences in void volumes associated with the print direction (p < 0.01) and part size (p < 0.01). Finite element models of splint parallel compression tests utilizing the Eeff dependent on print direction and size agreed with experimental closed compression tests of splints. Evaluating the microstructural properties of printed parts and selecting effective moduli for finite element models based on manufacturing parameters allows accurate prediction of device performance. These findings allow testing of a greater number of device design variants in silico to accomodate patient specific anatomies towards providing higher quality parts while lowering overall time and costs of manufacturing and testing.

Advanced Therapies for Severe Tracheobronchomalacia: A Review of the Use of 3D-Printed, Patient-Specific, Externally Implanted, Bioresorbable Airway Splints.

Tracheobronchomalacia is a condition of dynamic collapse of the trachea and mainstem bronchi. The clinical significance of tracheobronchomalacia depends on its severity. Mild cases may be medically managed with limited symptomology, while severe cases require advanced therapies, lengthy hospital stays, and carry significant morbidity and mortality. Current therapies for severe tracheobronchomalacia include tracheostomy with prolonged mechanical ventilation, aortopexy, tracheobronchopexy, and intraluminal metallic, silicone, or bioresorbable stents. Three-dimensional (3D)-printed, patient-specific, bioresorbable airway splinting is a novel treatment option that is undergoing investigation in a cohort of critically ill children with severe tracheobronchomalacia. At the time of our last review of our data, 29 splints had been implanted in 15 children with intrathoracic tracheobronchomalacia. The median follow-up was 8.5 months. There were 12 long-term survivors, and all but one lived at home. This article discusses the details of our institution's development and use of 3D-printed, patient-specific, bioresorbable splints for treatment of severe tracheobronchomalacia in the pediatric population.

Addressing the Pandemic Training Deficiency: Filling the Void with Simulation in Facial Reconstruction.

OBJECTIVE/HYPOTHESIS: To assess the use of a three-dimensional (3D) printed, multilayer facial flap model for use in trainee education as an alternative method of teaching surgical techniques of facial reconstruction. STUDY DESIGN: Cohort study. METHODS: A 3D printed facial flap simulator was designed from a computed tomography scan and manufactured out of silicone for low-cost, high-fidelity simulation. This simulator was tested by a group of Otolaryngology-Head and Neck Surgery trainees at a single institution. The simulator group was compared to a control group who completed an exercise on a traditional paper facial flap exercise. Both groups underwent didactic lectures prior to completing their respective exercises. Pre- and post-exercise Likert scale surveys measuring experience, understanding, effectiveness, and realism were completed by both groups. Central tendency, variability, and confidence intervals were measured to evaluate the outcomes. RESULTS: Trainees completing the facial flap simulator reported a statistically significant (p < 0.05) improvement in overall expertise in facial flap procedures, design of facial flaps, and excision of standing cutaneous deformities. No statistically significant improvement was seen in the control group. CONCLUSIONS: Trainees found the facial flap simulator to be an effective and useful training tool with a high level of realism in surgical education of facial reconstruction. Surgical simulators can serve as an adjunct to trainee education, especially during extraordinary times such as the novel coronavirus disease 2019 pandemic, which significantly impacted surgical training. LEVEL OF EVIDENCE: NA Laryngoscope, 131:E2444-E2448, 2021.

Competency-Based Assessment Tool for Pediatric Esophagoscopy: International Modified Delphi Consensus.

OBJECTIVES/HYPOTHESIS: Create a competency-based assessment tool for pediatric esophagoscopy with foreign body removal. STUDY DESIGN: Blinded modified Delphi consensus process. SETTING: Tertiary care center. METHODS: A list of 25 potential items was sent via the Research Electronic Data Capture database to 66 expert surgeons who perform pediatric esophagoscopy. In the first round, items were rated as "keep" or "remove" and comments were incorporated. In the second round, experts rated the importance of each item on a seven-point Likert scale. Consensus was determined with a goal of 7 to 25 final items. RESULTS: The response rate was 38/64 (59.4%) in the first round and returned questionnaires were 100% complete. Experts wanted to "keep" all items and 172 comments were incorporated. Twenty-four task-specific and 7 previously-validated global rating items were distributed in the second round, and the response rate was 53/64 (82.8%) with questionnaires returned 97.5% complete. Of the task-specific items, 9 reached consensus, 7 were near consensus, and 8 did not achieve consensus. For global rating items that were previously validated, 6 reached consensus and 1 was near consensus. CONCLUSIONS: It is possible to reach consensus about the important steps involved in rigid esophagoscopy with foreign body removal using a modified Delphi consensus technique. These items can now be considered when evaluating trainees during this procedure. This tool may allow trainees to focus on important steps of the procedure and help training programs standardize how trainees are evaluated. LEVEL OF EVIDENCE: 5. Laryngoscope, 131:1168-1174, 2021.

Modified Minerva Cervical Thoracic Orthosis for Postoperative Management of Cricotracheal Resection.

The worst complication of cricotracheal resection (CTR) is anastomotic dehiscence, and to limit it, postoperative management at Michigan Medicine included the use of a modified Minerva cervical-thoracic orthosis (MMCTO). To date, there has been no analysis of the risks and benefits of the brace's use following CTR. We analyze this with our retrospective study. A search with the keywords "cricotracheal resection" and "laryngotracheal reconstruction" was performed in the Electronic Medical Record Search Engine to identify patients retrospectively. The Statistical Package for Social Sciences was used for analysis; t test, χ2, and Fisher exact tests were used to analyze data. Fifteen males and 13 females with a median age of 4 years were identified, and almost 2/3 had a supra- and/or infrahyoid release performed. Postoperatively, 12 had a Grillo stitch and an MMCTO for a mean of 7 days. Most had no complications, but the most common complications were agitation due to brace discomfort and skin irritation. The worst complication was stroke. Our MMCTO's design allowed for better head and neck control with relative comfortability, and most patients had no complications with its short-term use. Our modification may be useful adjunct in the postoperative management.

Delivery system can vary ventilatory parameters across multiple patients from a single source of mechanical ventilation.

BACKGROUND: Current limitations in the supply of ventilators during the Covid19 pandemic have limited respiratory support for patients with respiratory failure. Split ventilation allows a single ventilator to be used for more than one patient but is not practicable due to requirements for matched patient settings, risks of cross-contamination, harmful interference between patients and the inability to individualize ventilator support parameters. We hypothesized that a system could be developed to circumvent these limitations. METHODS AND FINDINGS: A novel delivery system was developed to allow individualized peak inspiratory pressure settings and PEEP using a pressure regulatory valve, developed de novo, and an inline PEEP 'booster'. One-way valves, filters, monitoring ports and wye splitters were assembled in-line to complete the system and achieve the design targets. This system was then tested to see if previously described limitations could be addressed. The system was investigated in mechanical and animal trials (ultimately with a pig and sheep concurrently ventilated from the same ventilator). The system demonstrated the ability to provide ventilation across clinically relevant scenarios including circuit occlusion, unmatched physiology, and a surgical procedure, while allowing significantly different pressures to be safely delivered to each animal for individualized support. CONCLUSIONS: In settings of limited ventilator availability, systems can be developed to allow increased delivery of ventilator support to patients. This enables more rapid deployment of ventilator capacity under constraints of time, space and financial cost. These systems can be smaller, lighter, more readily stored and more rapidly deployable than ventilators. However, optimizing ventilator support for patients with individualized ventilation parameters will still be dependent upon ease of use and the availability of medical personnel.

A 3D-printed Lateral Skull Base Implant for Repair of Tegmen Defects: A Case Series.

OBJECTIVE: To determine the feasibility of a patient-specific, three-dimensionally (3D)-printed reconstruction plate for repair of lateral skull base defects. STUDY DESIGN: Prospective case series and cadaveric study. SETTING: A university-based, tertiary care hospital. PATIENTS: Three patients with lateral skull base defects and five cadavers. MAIN OUTCOME MEASURE(S): Caliper gauge fit testing was performed in the cadaver temporal bones to determine the fit of the tegmen plate in engaging the tegmen defect. Additionally, three patients underwent standard of care reconstruction of their middle fossa floor using autografts or allografts. Temporary plate insertion during standard operative repair was performed to gauge feasibility and fit. Operative time required for standard grafting compared with placement of the tegmen plate was examined. RESULTS: Real-time, intraoperative placement of the tegmen plate in our patients under 1 minute compared with nearly 60 minutes for standard surgical repair. Tegmen plates covered the defects and locked into place from contour matching without impinging on critical structures. Fit testing revealed flush-fitting plates to the cadaveric temporal bone surface with all gaps less than 500 µm. CONCLUSIONS: Computer modeling and 3D printing can design custom fitted tegmen reconstruction plates for temporal bone defects. Versatility in prefabrication and 3D modeling shows potential in allowing the construct to avoid critical structures and adequately cover defects with high precision to the tegmen surface.

Development and Multidisciplinary Preliminary Validation of a 3-Dimensional-Printed Pediatric Airway Model for Emergency Airway Front-of-Neck Access Procedures.

BACKGROUND: Pediatric-specific difficult airway guidelines include algorithms for 3 scenarios: unanticipated difficult tracheal intubation, difficult mask ventilation, and cannot intubate/cannot ventilate. While rare, these instances may require front-of-neck access (FONA) to secure an airway until a definitive airway can be established. The aim of this study was to develop a pediatric FONA simulator evaluated by both anesthesiology and otolaryngology providers, promoting multidisciplinary airway management. METHODS: A 3-dimensional-printed tracheal model was developed using rescaled, anatomically accurate dimensions from a computerized tomography scan using computer-aided design software. The medical grade silicone model was incorporated into a mannequin to create a low-cost, high-fidelity simulator. A multidisciplinary team of anesthesiology, otolaryngology, and simulation experts refined the model. Experts in airway management were recruited to rate the realism of the model's characteristics and features and their own ability to complete specific FONA-related tasks. RESULTS: Six expert raters (3 anesthesiology and 3 otolaryngology) were identified for multidisciplinary evaluation of model test content validity. Analysis of response data shows null variance within 1 or both specialties for a majority of the content validity tool elements. High and consistent absolute ratings for each domain indicate that the tested experts perceived this trainer as a realistic and highly valuable tool in its current state. CONCLUSIONS: The ability to practice front-of-neck emergency airway procedures safely and subsequently demonstrate proficiency on a child model has great implications regarding both quality of physician training and patient outcomes. This model may be incorporated into curricula to teach needle cricothyroidotomy and other FONA procedures to providers across disciplines.

Competency-Based Assessment Tool for Pediatric Tracheotomy: International Modified Delphi Consensus.

OBJECTIVES/HYPOTHESIS: Create a competency-based assessment tool for pediatric tracheotomy. STUDY DESIGN: Blinded, modified, Delphi consensus process. METHODS: Using the REDCap database, a list of 31 potential items was circulated to 65 expert surgeons who perform pediatric tracheotomy. In the first round, items were rated as "keep" or "remove," and comments were incorporated. In the second round, experts were asked to rate the importance of each item on a seven-point Likert scale. Consensus criteria were determined a priori with a goal of 7 to 25 final items. RESULTS: The first round achieved a response rate of 39/65 (60.0%), and returned questionnaires were 99.5% complete. All items were rated as "keep," and 137 comments were incorporated. In the second round, 30 task-specific and seven previously validated global rating items were distributed, and the response rate was 44/65 (67.7%), with returned questionnaires being 99.3% complete. Of the Task-Specific Items, 13 reached consensus, 10 were near consensus, and 7 did not achieve consensus. For the 7 previously validated global rating items, 5 reached consensus and two were near consensus. CONCLUSIONS: It is feasible to reach consensus on the important steps involved in pediatric tracheotomy using a modified Delphi consensus process. These items can now be considered to create a competency-based assessment tool for pediatric tracheotomy. Such a tool will hopefully allow trainees to focus on the important aspects of this procedure and help teaching programs standardize how they evaluate trainees during this procedure. LEVEL OF EVIDENCE: 5 Laryngoscope, 130:2700-2707, 2020.

Innovations in Airway Surgery.

The management of pediatric airway stenosis has evolved considerably over time. At the outset, dilation was the mainstay of management. In the 1900s, open surgery in the form of cricoid expansion procedures or resection procedures was the primary treatment with subsequent development of the slide tracheoplasty. Now in the twenty-first century, advances in endoscopic management, balloon dilation, and stenting, along with the advent of external scaffolds and tissue replacement continue to advance pediatric airway surgery.

Computer-Aided Design, 3-D-Printed Manufacturing, and Expert Validation of a High-fidelity Facial Flap Surgical Simulator.

IMPORTANCE: Facial flap procedures may be difficult for surgical trainees to conceptualize and challenging for supervising surgeons to allow entrustment early in training. Simulation outside of the operating room may accelerate and enhance the surgical education experience. OBJECTIVE: To design and manufacture a 3-dimensional (3-D)-printed, multilayer, anatomically accurate facial flap model for use in surgical education. DESIGN, SETTING, AND PARTICIPANTS: In this multicenter validation study, a 3-D-printed facial flap simulator was designed from a computed tomographic (CT) scan and manufactured for low-cost, high-fidelity simulation. Expert otolaryngology-head and neck surgeon feedback was acquired through surgical rehearsal and performance of 8 local facial flap procedures on the facial flap simulator by 7 otolaryngologists fellowship trained in facial plastic surgery. MAIN OUTCOMES AND MEASURES: Likert scale surveys were made based on evaluation criteria categorized into domains of realism, experience, and applicability of the simulator. Measures of central tendency, variability, and confidence intervals were generated to evaluate the outcomes. RESULTS: Seven expert otolaryngology-head and neck surgeons completed a Likert scale evaluation survey containing quantitative analysis of 6 questions on physical attributes, 12 questions on realism, 8 questions on experience, and 4 questions on the applicability of the simulator. All expert surgeons were additionally fellowship trained in facial plastic surgery with their mean years in practice being 11.9. Overall evaluation demonstrated valuable ability of the simulator for medical education with suggestions for future directions. Importantly, the simulator was rated on a scale of 1 (no value) to 4 (great value) as 3.86 as a training tool, 3.57 as a competency evaluation tool, and 3.43 as a rehearsal tool. CONCLUSIONS AND REVELANCE: Expert experience with the local facial flap simulator was rated highly for realism, experience, performance, and usefulness. With slight refinement, the model has strong potential for broad use in training in otolaryngology-head and neck surgery and facial plastic surgery. LEVEL OF EVIDENCE: NA.

3D-printed, externally-implanted, bioresorbable airway splints for severe tracheobronchomalacia.

OBJECTIVES/HYPOTHESIS: To report the clinical safety and efficacy of three-dimensional (3D)-printed, patient-specific, bioresorbable airway splints in a cohort of critically ill children with severe tracheobronchomalacia. STUDY DESIGN: Case series. METHODS: From 2012 to 2018, 15 subjects received 29 splints on their trachea, right and/or left mainstem bronchi. The median age at implantation was 8 months (range, 3-25 months). Nine children were female. Five subjects had a history of extracorporeal membrane oxygenation (ECMO), and 11 required continuous sedation, six of whom required paralytics to maintain adequate ventilation. Thirteen were chronically hospitalized, unable to be discharged, and seven were hospitalized their entire lives. At the time of splint implantation, one subject required ECMO, one required positive airway pressure, and 13 subjects were tracheostomy and ventilator dependent, requiring a median positive end-expiratory pressure (PEEP) of 14 cm H2 O (range, 6-20 cm H2 0). Outcomes collected included level of respiratory support, disposition, and splint-related complications. RESULTS: At the time of discharge from our institution, at a median of 28 days postimplantation (range, 10-56 days), the subject on ECMO was weaned from extracorporeal support, and the subjects who were ventilated via tracheostomy had a median change in PEEP (discharge-baseline) of -2.5 cm H2 O (range, -15 to 2 cm H2 O, P = .022). At median follow-up of 8.5 months (range, 0.3-77 months), all but one of the 12 surviving subjects lives at home. Of the 11 survivors who were tracheostomy dependent preoperatively, one is decannulated, one uses a speaking valve, six use a ventilator exclusively at night, and three remain ventilator dependent. CONCLUSIONS: This case series demonstrates the initial clinical efficacy of the 3D-printed bioresorbable airway splint device in a cohort of critically ill children with severe tracheobronchomalacia. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:1763-1771, 2019.

Secondary lymphoid organ fibroblastic reticular cells mediate trans-infection of HIV-1 via CD44-hyaluronan interactions.

Fibroblastic reticular cells (FRCs) are stromal cells in secondary lymphoid organs, the major sites for HIV-1 infection of CD4+ T cells. Although FRCs regulate T cell survival, proliferation, and migration, whether they play any role in HIV-1 spread has not been studied. Here, we show that FRCs enhance HIV-1 spread via trans-infection in which FRCs capture HIV-1 and facilitate infection of T cells that come into contact with FRCs. FRCs mediate trans-infection in both two- and three-dimensional culture systems and in a manner dependent on the virus producer cells. This producer cell dependence, which was also observed for virus spread in secondary lymphoid tissues ex vivo, is accounted for by CD44 incorporated into virus particles and hyaluronan bound to such CD44 molecules. This virus-associated hyaluronan interacts with CD44 expressed on FRCs, thereby promoting virus capture by FRCs. Overall, our results reveal a novel role for FRCs in promoting HIV-1 spread.

Co-culture of adipose-derived stem cells and chondrocytes on three-dimensionally printed bioscaffolds for craniofacial cartilage engineering.

OBJECTIVES/HYPOTHESIS: Reconstruction of craniofacial cartilagenous defects are among the most challenging surgical procedures in facial plastic surgery. Bioengineered craniofacial cartilage holds immense potential to surpass current reconstructive options, but limitations to clinical translation exist. We endeavored to determine the viability of utilizing adipose-derived stem cell-chondrocyte co-culture and three-dimensional (3D) printing to produce 3D bioscaffolds for cartilage tissue engineering. We describe a feasibility study revealing a novel approach for cartilage tissue engineering with in vitro and in vivo animal data. METHODS: Porcine adipose-derived stem cells and chondrocytes were isolated and co-seeded at 1:1, 2:1, 5:1, 10:1, and 0:1 experimental ratios in a hyaluronic acid/collagen hydrogel in the pores of 3D-printed polycaprolactone scaffolds to form 3D bioscaffolds for cartilage tissue engineering. Bioscaffolds were cultured in vitro without growth factors for 4 weeks and then implanted into the subcutaneous tissue of athymic rats for an additional 4 weeks before sacrifice. Bioscaffolds were subjected to histologic, immunohistochemical, and biochemical analysis. RESULTS: Successful production of cartilage was achieved using a co-culture model of adipose-derived stem cells and chondrocytes without the use of exogenous growth factors. Histology demonstrated cartilage growth for all experimental ratios at the post-in vivo time point confirmed with type II collagen immunohistochemistry. There was no difference in sulfated-glycosaminoglycan production between experimental groups. CONCLUSION: Tissue-engineered cartilage was successfully produced on 3D-printed bioresorbable scaffolds using an adipose-derived stem cell and chondrocyte co-culture technique. This potentiates co-culture as a solution for several key barriers to a clinically translatable cartilage tissue engineering process. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:E251-E257, 2018.