Decellularized tracheal scaffolds offer a potential solution for the repair of long-segment tracheal defects. However, complete decellularization of trachea is complicated by tracheal collapse. We created a partially decellularized tracheal scaffold (DTS) and characterized regeneration in a mouse model of tracheal transplantation. All cell populations except chondrocytes were eliminated from DTS. DTS maintained graft integrity as well as its predominant extracellular matrix (ECM) proteins. We then assessed the performance of DTS in vivo. Grafts formed a functional epithelium by study endpoint (28 days). While initial chondrocyte viability was low, this was found to improve in vivo. We then used atomic force microscopy to quantify micromechanical properties of DTS, demonstrating that orthotopic implantation and graft regeneration lead to the restoration of native tracheal rigidity. We conclude that DTS preserves the cartilage ECM, supports neo-epithelialization, endothelialization and chondrocyte viability, and can serve as a potential solution for long-segment tracheal defects.

Collagen is the most abundant airway extracellular matrix component and is the primary determinant of mechanical airway properties. Abnormal airway collagen deposition is associated with the pathogenesis and progression of airway disease. Thus, understanding how collagen affects healthy airway tissue mechanics is essential. The impact of abnormal collagen deposition and tissue stiffness has been an area of interest in pulmonary diseases such as cystic fibrosis, asthma, and chronic obstructive pulmonary disease. In this review, we discuss (1) the role of collagen in airway mechanics, (2) macro- and micro-scale approaches to quantify airway mechanics, and (3) pathologic changes associated with collagen deposition in airway diseases. These studies provide important insights into the role of collagen in airway mechanics. We summarize their achievements and seek to provide biomechanical clues for targeted therapies and regenerative medicine to treat airway pathology and address airway defects.

Objective Limited research exists on the coronavirus disease 2019 (COVID-19) pandemic pertaining to otolaryngology–head and neck surgery (OHNS). The present study seeks to understand the response of OHNS workflows in the context of policy changes and to contribute to developing preparatory guidelines for perioperative management in OHNS. Study Design Retrospective cohort study. Setting Pediatric and general adult academic medical centers and a Comprehensive Cancer Center (CCC). Subjects and Methods OHNS cases from March 18 to April 8, 2020—the 3 weeks immediately following the Ohio state-mandated suspension of all elective surgery on March 18, 2020—were compared with a 2019 control data set. Results During this time, OHNS at the general adult and pediatric medical centers and CCC experienced 87.8%, 77.1%, and 32% decreases in surgical procedures as compared with 2019, respectively. Aerosol-generating procedures accounted for 86.8% of general adult cases, 92.4% of pediatric cases, and 62.0% of CCC cases. Preoperative COVID-19 testing occurred in 7.1% of general adult, 9% of pediatric, and 6.9% of CCC cases. The majority of procedures were tiers 3a and 3b per the Centers for Medicare & Medicaid Services. Aerosol-protective personal protective equipment (PPE) was worn in 28.6% of general adult, 90% of pediatric, and 15.5% of CCC cases. Conclusion For OHNS, the majority of essential surgical cases remained high-risk aerosol-generating procedures. Preoperative COVID-19 testing and intraoperative PPE usage were initially inconsistent; systemwide guidelines were developed rapidly but lagged behind recommendations of the OHNS department and its academy. OHNS best practice standards are needed for preoperative COVID-19 status screening and PPE usage as we begin national reopening.

ObjectiveTo evaluate clinical and audiometric outcomes of adult and pediatric patients implanted with a semi-implantable transcutaneous active bone-conduction implant.Study DesignRetrospective chart review.SettingTwo tertiary referral centers.PatientsSubjects implanted with the semi-implantable transcutaneous active bone-conduction implant called BoneBridge.InterventionImplantation of the BoneBridge and audiometric evaluations.Main Outcome MeasuresAudiometric, clinical, and surgical outcomes as well as complications.ResultsForty-two adults and 20 children were implanted for conductive or mixed hearing loss as well as single-sided deafness. Implantation significantly improved mean air-conduction pure-tone average from 72.8 ± 22.3 to 35 ± 9 dB in adults and from 65.7 ± 24.3 to 19.6 ± 8.2 dB in children (both p < 0.001). Word recognition score improved from 63.7 ± 38.8% to 85.6 ± 10.6% in adults and 57.8 ± 38% to 89.3 ± 10.1% in children (both p < 0.05). The rate of revision surgery was 11.3%, with four patients (6.5%) undergoing removal for device-related complications, two (3.2%) for complications associated with implantation, and one (1.6%) for device failure secondary to external trauma.ConclusionsIn a large retrospective series consisting of both pediatric and adult patients, implantation with a transcutaneous active bone-conduction implant was found to be a reliable aural rehabilitation option for a variety of hearing loss etiologies.

Objectives/Hypothesis Partially decellularized tracheal scaffolds have emerged as a potential solution for long‐segment tracheal defects. These grafts have exhibited regenerative capacity and the preservation of native mechanical properties resulting from the elimination of all highly immunogenic cell types while sparing weakly immunogenic cartilage. With partial decellularization, new considerations must be made about the viability of preserved chondrocytes. In this study, we propose a multimodal approach for quantifying chondrocyte viability for airway tissue engineering. Methods Tracheal segments (5 mm) were harvested from C57BL/6 mice, and immediately stored in phosphate‐buffered saline at −20°C (PBS‐20) or biobanked via cryopreservation. Stored and control (fresh) tracheal grafts were implanted as syngeneic tracheal grafts (STG) for 3 months. STG was scanned with micro‐computed tomography (μCT) in vivo. STG subjected to different conditions (fresh, PBS‐20, or biobanked) were characterized with live/dead assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and von Kossa staining. Results Live/dead assay detected higher chondrocyte viability in biobanked conditions compared to PBS‐20. TUNEL staining indicated that storage conditions did not alter the proportion of apoptotic cells. Biobanking exhibited a lower calcification area than PBS‐20 in 3‐month post‐implanted grafts. Higher radiographic density (Hounsfield units) measured by μCT correlated with more calcification within the tracheal cartilage. Conclusions We propose a strategy to assess chondrocyte viability that integrates with vivo imaging and histologic techniques, leveraging their respective strengths and weaknesses. These techniques will support the rational design of partially decellularized tracheal scaffolds. Level of Evidence N/A Laryngoscope, 133:512–520, 2023

Objectives: Virtual reality (VR) simulation for patient-specific pre-surgical planning and rehearsal requires accurate segmentation of key surgical landmark structures such as the facial nerve, ossicles, and cochlea. The aim of this study was to explore different approaches to segmentation of temporal bone surgical anatomy for patient-specific VR simulation. Methods: De-identified, clinical computed tomography imaging of 9 pediatric patients aged 3 months to 12 years were obtained retrospectively. The patients represented normal anatomy and key structures were manually segmented using open source software. The OTOPLAN (CAScination AG, Bern, Switzerland) otological planning software was used for guided segmentation. An atlas-based algorithm was used for computerized, automated segmentation. Experience with the different approaches as well as time and resulting models were compared. Results: Manual segmentation was time consuming but also the most flexible. The OTOPLAN software is not designed specifically for our purpose and therefore the number of structures that can be segmented is limited, there was some user-to-user variation as well as volume differences compared with manual segmentation. The atlas-based automated segmentation potentially allows a full range of structures to be segmented and produces segmentations comparable to those of manual segmentation with a processing time that is acceptable because of the minimal user interaction. Conclusion: Segmentation is fundamental for patient-specific VR simulation for pre-surgical planning and rehearsal in temporal bone surgery. The automated segmentation algorithm currently offers the most flexible and feasible approach and should be implemented. Further research is needed in relation to cases of abnormal anatomy. Level of evidence: 4

Mutation of the APC gene occurs in a high percentage of colorectal tumors and is a central event driving tumor initiation in the large intestine. The APC protein performs multiple tumor suppressor functions including negative regulation of the canonical WNT signaling pathway by both cytoplasmic and nuclear mechanisms. Published reports that APC interacts with β-catenin in the chromatin fraction to repress WNT-activated targets have raised the possibility that chromatin-associated APC participates more broadly in mechanisms of transcriptional control. This screening study has used chromatin immunoprecipitation and next-generation sequencing to identify APC-associated genomic regions in colon cancer cell lines. Initial target selection was performed by comparison and statistical analysis of 3,985 genomic regions associated with the APC protein to whole transcriptome sequencing data from APC-deficient and APC-wild-type colon cancer cells, and two types of murine colon adenomas characterized by activated Wnt signaling.289 transcripts altered in expression following APC loss in human cells were linked to APC-associated genomic regions. High-confidence targets additionally validated in mouse adenomas included 16 increased and 9 decreased in expression following APC loss, indicating that chromatin-associated APC may antagonize canonical WNT signaling at both WNT-activated and WNT-repressed targets. Motif analysis and comparison to ChIP-seq datasets for other transcription factors identified a prevalence of binding sites for the TCF7L2 and AP-1 transcription factors in APC-associated genomic regions. Our results indicate that canonical WNT signaling can collaborate with or antagonize the AP-1 transcription factor to fine-tune the expression of shared target genes in the colorectal epithelium. Future therapeutic strategies for APC-deficient colorectal cancers might be expanded to include agents targeting the AP-1 pathway.

Objective To demonstrate DNA sequencing analysis (DNAsa) of sinus cultures in patients with CRS is a reliable method of detecting pathogens in polymicrobial CRS infections. Methods After obtaining Institutional Review Board approval for this prospective cohort study, we selected a random sample of 50 patients with CRS at Medstar Georgetown University Hospital between September 2016 and March 2017. We defined CRS as a history of rhinosinusitis refractory to maximal medical therapy and prior endoscopic sinus surgery. Patients demonstrating active purulence in a sinus cavity were prospectively selected to undergo standard hospital cultures (SHC) and DNAsa cultures. Organisms identified in both methods were compared for each patient. Results Specimens were obtained from 29 female and 16 male patients with a mean age of 50 years. A total of 45 cultures were included in our final analysis; five cultures were excluded after inappropriate laboratory processing. Results from these patients were compared and analyzed. Cohen's weighted kappa analysis showed agreement between the two testing methods in identifying predominant microorganisms. DNAsa detected 31.9% more microorganisms compared to SHC ( P < 0.05). When multiple microorganisms were detected, DNAsa yielded more positive results compared to SHC ( P < 0.05). Conclusions DNAsa detects all microorganisms identified by SHC as well as predominant microorganisms not detected by SHC. Thus molecular pathogen identification may be more reliable for identifying multiple microorganisms as compared to standard culture techniques that identify only one or two microorganisms. In recalcitrant cases of CRS, DNAsa may provide better guidance in selection of appropriate antimicrobial treatment.