Computational Fluid Dynamics and Its Potential Applications for the ENT Clinician.

This article is an examination of computational fluid dynamics in the field of otolaryngology, specifically rhinology. The historical development and subsequent application of computational fluid dynamics continues to enhance our understanding of various sinonasal conditions and surgical planning in the field today. This article aims to provide a description of computational fluid dynamics, the methods for its application, and the clinical relevance of its results. Consideration of recent research and data in computational fluid dynamics demonstrates its use in nonhistological disease pathology exploration, accompanied by a large potential for surgical guidance applications. Additionally, this article defines in lay terms the variables analyzed in the computational fluid dynamic process, including velocity, wall shear stress, area, resistance, and heat flux.

Neisseria meningitidis on Sinonasal Culture for Sinusitis: A Case Series and Literature Review.

Neisseria meningitidis is carried asymptomatically in the nasopharynx and is most known for causing septicemia and meningitis; however, the pathogenesis and incidence rates of N. meningitidis sinusitis are not well described. This case series describes four patients from a tertiary medical center who presented with culture-positive N. meningitidis sinusitis within a nine-month period. Three patients had complete resolution of symptoms after treatment with the appropriate antibiotic regimen, with one patient requiring functional endoscopic sinus surgery. We encourge providers to advocate for vaccination in their young adult unvaccinated patients, as each patient here was not appropriately vaccinated according to CDC guidelines. Laryngoscope, 134:1603-1605, 2024.

How Does Oxymetazoline Change Nasal Aerodynamics and Symptomatology in Patients with Turbinate Hypertrophy?

OBJECTIVES: Oxymetazoline relieves nasal obstructive symptoms via vasoconstriction, however, the changes in nasal structures and aerodynamics that impact symptoms the most remain unclear. METHODS: This prospective, longitudinal, and single blinded cohort study applied Computational Fluid Dynamic (CFD) modeling based on CT scans at baseline and post-oxymetazoline on 13 consecutive patients with chronic nasal obstruction secondary to inferior turbinate hypertrophy from a tertiary medical center. To account for placebo effect, a sham saline spray was administered with subject blindfolded prior to oxymetazoline, with 30 min rest in between. Nasal Obstruction Symptom Evaluation (NOSE) and unilateral Visual Analogue Scale (VAS) scores of nasal obstructions were collected at baseline, after sham, and 30 min after oxymetazoline. RESULTS: Both VAS and NOSE scores significantly improved from baseline to post-oxymetazoline (NOSE: 62.3 ± 12.4 to 31.5 ± 22.5, p < 0.01; VAS: 5.27 ± 2.63 to 3.85 ± 2.59, p < 0.05), but not significantly from baseline to post-sham. The anatomical effects of oxymetazoline were observed broadly throughout the entire length of the inferior and middle turbinates (p < 0.05). Among many variables that changed significantly post-oxymetazoline, only decreased nasal resistance (spearman r = 0.4, p < 0.05), increased regional flow rates (r = -0.3 to -0.5, p < 0.05) and mucosal cooling heat flux (r = -0.42, p < 0.01) in the inferior but not middle turbinate regions, and nasal valve Wall Shear Stress (WSS r = -0.43, p < 0.05) strongly correlated with symptom improvement. CONCLUSION: Oxymetazoline broadly affects the inferior and middle turbinates, however, symptomatic improvement appears to be driven more by global nasal resistance and regional increases in airflow rate, mucosal cooling, and WSS, especially near the head of the inferior turbinate. LEVEL OF EVIDENCE: 3: Well-designed, prospective, single blinded cohort trial. Laryngoscope, 134:1100-1106, 2024.

Assessing the concern for airway complications introduced by Wendler's glottoplasty.

Objective: Wendler's glottoplasty (WG) is a pitch-elevating surgery performed by laryngologists providing gender-affirming care. The surgery creates an anterior glottic web that could theoretically cause airway concerns, either perioperatively or at the time of future procedures; such concerns are not well-described in the literature. We seek to assess surgeon opinions on airway concerns regarding WG. Method: A survey of laryngologists assessing opinions on airway considerations in glottoplasty. Results: A total of 19 physicians responded, representing approximately 193 surgeries. 52.6% performed glottoplasty and the remainder responded based on experience with anterior glottic webs. Two perioperative airway complications were reported, both mild stridor that did not prevent same-day discharge. No long-term sequela was reported. All surveyed laryngologists endorsed an altered general anesthetic approach for future procedures, with 73.7% advocating for use of a smaller endotracheal tube. 72.2% did not have "major concerns" about future intubations, and only 5.3% thought the immediate risk of airway compromise was a "real concern." 91.9% counsel their patients routinely but briefly on airway concerns. Open-ended comments conveyed themes of concern for post-operative disruption of the web more than of airway compromise. Conclusion: Because glottoplasty is performed in the anterior glottis and does not significantly impact airway patency, the risk of serious airway complications appears to be minimal. Laryngologists believe future intubations require a modified approach with a smaller tube, partly due to concern for glottic web trauma. Based on this pilot study, the topic deserves greater work to standardize care and anesthetic alterations for patients with WG. Level of Evidence: 5.

Cartilage diversification and modularity drove the evolution of the ancestral vertebrate head skeleton.

The vertebrate head skeleton has evolved a myriad of forms since their divergence from invertebrate chordates. The connection between novel gene expression and cell types is therefore of importance in this process. The transformation of the jawed vertebrate (gnathostome) head skeleton from oral cirri to jointed jaw elements required a diversity of cartilages as well as changes in the patterning of these tissues. Although lampreys are a sister clade to gnathostomes, they display skeletal diversity with distinct gene expression and histologies, a useful model for addressing joint evolution. Specifically, the lamprey tissue known as mucocartilage has noted similarities with the jointed elements of the mandibular arch in jawed vertebrates. We thus asked whether the cells in lamprey mucocartilage and gnathostome joint tissue could be considered homologous. To do this, we characterized new genes that are involved in gnathostome joint formation and characterized the histochemical properties of lamprey skeletal types. We find that most of these genes are minimally found in mucocartilage and are likely later innovations, but we do identify new activity for gdf5/6/7b in both hyaline and mucocartilage, supporting its role as a chondrogenic regulator. Contrary to previous works, our histological assays do not find any perichondrial fibroblasts surrounding mucocartilage, suggesting that mucocartilage is non-skeletogenic tissue that is partially chondrified. Interestingly, we also identify new histochemical features of the lamprey otic capsule that diverge from normal hyaline. Paired with our new insights into lamprey mucocartilage, we propose a broader framework for skeletal evolution in which an ancestral soxD/E and gdf5/6/7 network directs mesenchyme along a spectrum of cartilage-like features.

The Composition and Cellular Sources of CSPGs in the Glial Scar After Spinal Cord Injury in the Lamprey.

Axon regrowth after spinal cord injury (SCI) is inhibited by several types of inhibitory extracellular molecules in the central nervous system (CNS), including chondroitin sulfate proteoglycans (CSPGs), which also are components of perineuronal nets (PNNs). The axons of lampreys regenerate following SCI, even though their spinal cords contain CSPGs, and their neurons are enwrapped by PNNs. Previously, we showed that by 2 weeks after spinal cord transection in the lamprey, expression of CSPGs increased in the lesion site, and thereafter, decreased to pre-injury levels by 10 weeks. Enzymatic digestion of CSPGs in the lesion site with chondroitinase ABC (ChABC) enhanced axonal regeneration after SCI and reduced retrograde neuronal death. Lecticans (aggrecan, versican, neurocan, and brevican) are the major CSPG family in the CNS. Previously, we cloned a cDNA fragment that lies in the most conserved link-domain of the lamprey lecticans and found that lectican mRNAs are expressed widely in lamprey glia and neurons. Because of the lack of strict one-to-one orthology with the jawed vertebrate lecticans, the four lamprey lecticans were named simply A, B, C, and D. Using probes that distinguish these four lecticans, we now show that they all are expressed in glia and neurons but at different levels. Expression levels are relatively high in embryonic and early larval stages, gradually decrease, and are upregulated again in adults. Reductions of lecticans B and D are greater than those of A and C. Levels of mRNAs for lecticans B and D increased dramatically after SCI. Lectican D remained upregulated for at least 10 weeks. Multiple cells, including glia, neurons, ependymal cells and microglia/macrophages, expressed lectican mRNAs in the peripheral zone and lesion center after SCI. Thus, as in mammals, lamprey lecticans may be involved in axon guidance and neuroplasticity early in development. Moreover, neurons, glia, ependymal cells, and microglia/macrophages, are responsible for the increase in CSPGs during the formation of the glial scar after SCI.

A Comprehensive Analysis of Fibrillar Collagens in Lamprey Suggests a Conserved Role in Vertebrate Musculoskeletal Evolution.

Vertebrates have distinct tissues which are not present in invertebrate chordates nor other metazoans. The rise of these tissues also coincided with at least one round of whole-genome duplication as well as a suite of lineage-specific segmental duplications. Understanding whether novel genes lead to the origin and diversification of novel cell types, therefore, is of great importance in vertebrate evolution. Here we were particularly interested in the evolution of the vertebrate musculoskeletal system, the muscles and connective tissues that support a diversity of body plans. A major component of the musculoskeletal extracellular matrix (ECM) is fibrillar collagens, a gene family which has been greatly expanded upon in vertebrates. We thus asked whether the repertoire of fibrillar collagens in vertebrates reflects differences in the musculoskeletal system. To test this, we explored the diversity of fibrillar collagens in lamprey, a jawless vertebrate which diverged from jawed vertebrates (gnathostomes) more than five hundred million years ago and has undergone its own gene duplications. Some of the principal components of vertebrate hyaline cartilage are the fibrillar collagens type II and XI, but their presence in cartilage development across all vertebrate taxa has been disputed. We particularly emphasized the characterization of genes in the lamprey hyaline cartilage, testing if its collagen repertoire was similar to that in gnathostomes. Overall, we discovered thirteen fibrillar collagens from all known gene subfamilies in lamprey and were able to identify several lineage-specific duplications. We found that, while the collagen loci have undergone rearrangement, the Clade A genes have remained linked with the hox clusters, a phenomenon also seen in gnathostomes. While the lamprey muscular tissue was largely similar to that seen in gnathostomes, we saw considerable differences in the larval lamprey skeletal tissue, with distinct collagen combinations pertaining to different cartilage types. Our gene expression analyses were unable to identify type II collagen in the sea lamprey hyaline cartilage nor any other fibrillar collagen during chondrogenesis at the stages observed, meaning that sea lamprey likely no longer require these genes during early cartilage development. Our findings suggest that fibrillar collagens were multifunctional across the musculoskeletal system in the last common ancestor of vertebrates and have been largely conserved, but these genes alone cannot explain the origin of novel cell types.

Lamprey lecticans link new vertebrate genes to the origin and elaboration of vertebrate tissues.

The evolution of vertebrates from an invertebrate chordate ancestor involved the evolution of new organs, tissues, and cell types. It was also marked by the origin and duplication of new gene families. If, and how, these morphological and genetic innovations are related is an unresolved question in vertebrate evolution. Hyaluronan is an extracellular matrix (ECM) polysaccharide important for water homeostasis and tissue structure. Vertebrates possess a novel family of hyaluronan binding proteins called Lecticans, and studies in jawed vertebrates (gnathostomes) have shown they function in many of the cells and tissues that are unique to vertebrates. This raises the possibility that the origin and/or expansion of this gene family helped drive the evolution of these vertebrate novelties. In order to better understand the evolution of the lectican gene family, and its role in the evolution of vertebrate morphological novelties, we investigated the phylogeny, genomic arrangement, and expression patterns of all lecticans in the sea lamprey (Petromyzon marinus), a jawless vertebrate. Though both P. marinus and gnathostomes each have four lecticans, our phylogenetic and syntenic analyses are most consistent with the independent duplication of one of more lecticans in the lamprey lineage. Despite the likely independent expansion of the lamprey and gnathostome lectican families, we find highly conserved expression of lecticans in vertebrate-specific and mesenchyme-derived tissues. We also find that, unlike gnathostomes, lamprey expresses its lectican paralogs in distinct subpopulations of head skeleton precursors, potentially reflecting an ancestral diversity of skeletal tissue types. Together, these observations suggest that the ancestral pre-duplication lectican had a complex expression pattern, functioned to support mesenchymal histology, and likely played a role in the evolution of vertebrate-specific cell and tissue types.

Disentangling the Relations between Social Identity and Prosocial and Antisocial Behavior in Competitive Youth Sport.

The social identities formed through membership on extracurricular activity groups may contribute to the frequency with which youth engage in prosocial and antisocial behavior. However, researchers have yet to disentangle the individual- and group-level processes social identification effects operate through; sex and perceived norms may also moderate such effects. Thus, we investigated the hierarchical and conditional relations between three dimensions of social identity (i.e., ingroup ties, cognitive centrality, ingroup affect) and prosocial and antisocial behavior in youth ice hockey players (N = 376; 33% female). Multilevel analyses demonstrated antisocial teammate and opponent behavior were predicted by cognitive centrality at the team level. Further, prosocial teammate behavior was predicted by cognitive centrality and ingroup ties at the individual-level. Also, perceived norms for prosocial teammate behavior moderated the relations between ingroup ties, cognitive centrality, and ingroup affect and prosocial teammate behaviour. Finally, sex moderated the relations between cognitive centrality/ingroup affect and antisocial opponent behavior. This work demonstrates the multilevel and conditional nature of how social identity dimensions relate to youth prosocial and antisocial behavior.