Objective

There is little knowledge about the histological organization of facial and costal cartilages in terms of matrix structure and cell morphology. Second harmonic generation (SHG) imaging is a nonlinear imaging technique that capitalizes on signal generation from highly ordered macromolecules such as collagen fibers. The purpose of this study was to use SHG microscopy to image collagen extracellular matrix (ECM) structure, chondrocyte size, and density of these cartilages.

Study design

Experimental.

Methods

Surgical remnants of septal, lower lateral, rib, and auricular cartilages were collected following surgery, sectioned into 0.5-1 mm thick samples and fixed to facilitate batch process imaging. A Leica TCS SP8 MP Microscope and multiphoton laser were used to image the specimens. Images were analyzed for cell size, cell density, and collagen fiber directionality patterns using ImageJ.

Results

SHG images of septal specimens show mesh-like structure of the ECM. There appears to be a superficial layer, characterized by flattened lacunae and middle zone, marked by circular lacunae clusters, similar to what is observed in articular cartilage. The structure of the ECM depicts a visible orientation perpendicular to the surface of the perichondrium. Cell size and density analysis through ImageJ suggests variety across cartilage types. Directionality analysis indicates that the collagen in the ECM displays preferred direction.

Conclusion

This study establishes clear extracellular models of facial and costal cartilages. Limitations include heterogeneous cartilage thickness due to processing difficulties. Further studies include automating the cutting process to increase uniformity of tissue thickness and increasing sample size to further validate results.

Level of evidence

2 Laryngoscope, 133:3370-3377, 2023.

Background: A "boomerang" graft is an end-to-end caudal septal extension graft (SEG) that conforms to the geometry of the anterior septal angle, and avoids septal overlap, unlike a side-to-side SEG. Objective: To compare breathing improvements in rhinoplasty patients receiving boomerang SEGs and patients receiving side-to-side SEGs. Methods: Retrospective cohort analysis of patients undergoing rhinoplasty with either end-to-end boomerang SEG or a side-to-side SEG. Functional outcomes were assessed through the Nasal Obstruction Symptom Evaluation (NOSE) survey. Results: The boomerang SEG cohort had a mean age of 34 years and were 68% female compared with 38 years and 67% female in the side-to-side SEG cohort (p > 0.05). The cohorts did not differ in the proportion of the lateral crural tensioning, spreader graft placement, or history of rhinoplasty. The boomerang cohort demonstrated a 67% reduction in NOSE scores compared with a 70% reduction among the side-to-side SEG cohort (p = 0.14). Men undergoing boomerang graft placement reported significantly less postoperative functional improvement than men undergoing placement of a side-to-side SEG (62% vs. 77%, p = 0.01). Conclusion: Use of a boomerang graft is not likely to negatively affect rhinoplasty functional outcomes when compared with a side-to-side SEG.

With the widespread adoption of intranasal radiofrequency (RF) devices, our objective was to report national adverse events (AEs) associated with their use. The Food and Drug Administration's Manufacturer and User Facility Device Experience was queried. A total of 24 device-related AEs were reported, 11 (45.8%) for Celon® (Olympus), 3 (12.5%) for Vivaer® (Aerin), 2 (8.3%) for Neuromark® (Neurent), and 8 (33.3%) for Rhinaer® (Aerin). Seven (63.6%) of the Celon®-related complications were related to tissue necrosis (largely user error-related), but 1 (9.1%) episode of pediatric ocular palsy was also reported. Vivaer® complications included synechiae formation, a mucosal perforation, and a case of empty nose syndrome. Of the posterior nasal nerve ablating devices, 9 of 10 AEs were epistaxes, of which 7 (77.8%) required operative intervention. Surgeons should exercise vigilance and tissue-appropriate device settings when utilizing RF devices. Epistaxis and tissue necrosis may occur, as well as more rare, but devastating, complications.

The Center for Disease Control and Prevention estimates that 75% of reported cases of traumatic brain injury (TBI) are mild, where chronic pain and depression are 2 of the most common symptoms. In this study, we used a murine model of repeated mild TBI to characterize the associated pain hypersensitivity and affective-like behavior and to what extent microglial reactivity contributes to these behavioral phenotypes. Male and female C57BL/6J mice underwent sham or repeated mild traumatic brain injury (rmTBI) and were tested for up to 9 weeks postinjury, where an anti-inflammatory/neuroprotective drug (minocycline) was introduced at 5 weeks postinjury in the drinking water. Repeated mild traumatic brain injury mice developed cold nociceptive hypersensitivity and negative affective states, as well as increased locomotor activity and risk-taking behavior. Minocycline reversed negative affect and pain hypersensitivities in male but not female mice. Repeated mild traumatic brain injury also produced an increase in microglial and brain-derived neurotropic factor mRNA transcripts in limbic structures known to be involved in nociception and affect, but many of these changes were sex dependent. Finally, we show that the antiepileptic drug, gabapentin, produced negative reinforcement in male rmTBI mice that was prevented by minocycline treatment, whereas rmTBI female mice showed a place aversion to gabapentin. Collectively, pain hypersensitivity, increased tonic-aversive pain components, and negative affective states were evident in both male and female rmTBI mice, but suppression of microglial reactivity was only sufficient to reverse behavioral changes in male mice. Neuroinflammation in limbic structures seems to be a contributing factor in behavioral changes resulting from rmTBI.

Chemical injuries to the cornea account for 11 to 22% of all ocular injuries. Acidic injuries are commonly due to sulfuric, hydrochloric, hydrofluoric, and battery acids, while basic injuries are commonly due to sodium hydroxide, chlorine bleach, and ammonia products. We have previously studied potential-driven electrochemical clearing (P-ECC) for alkaline injuries. In this study, we investigated the use of P-ECC on both acidic and alkaline injuries to determine its effect on restoring corneal transparency. Optical coherence tomography (OCT) was performed before and after P-ECC to determine adequate corneal clearing. Severity of chemical injury was measured through second harmonic generation (SHG) imaging. HCl or NaOH was applied to the corneas of New Zealand white rabbit globes. P-ECC was performed on opacified cornea while OCT imaging was simultaneously performed to evaluate depth resolved clarity. SHG imaging evaluated the structure of collagen before HCl or NaOH application and after P-ECC. Irrigation with water served as positive control. Native rabbit corneas were used as a negative control group. P-ECC induced clearing in the rabbit cornea, shown through OCT. Clearing occurred in regions where the working electrode made contact with the cornea. SHG imaging showed restoration of collagen fibril signal in P-ECC treated corneas compared to control. P-ECC is a potentially effective therapy for clearing acidic and alkaline corneal injuries. However, more ex-vivo experiments are required to determine the specific parameter for optimal clearing. In-vivo experiments are necessary to determine its potential for clinical use.

Objective

Drug induced sleep endoscopy (DISE) is often performed for pediatric obstructive sleep apnea (OSA) when initial diagnostic studies do not provide adequate information for therapy. However, DISE scoring is subjective and with limitations. This proof-of-concept study demonstrates the use of a novel long-range optical coherence tomography (LR-OCT) system during DISE of two pediatric patients.

Methods

LR-OCT was used to visualize the airway of pediatric patients during DISE. At the conclusion of DISE, the OCT probe was guided in the airway under endoscopic visual guidance, and cross-sectional images were acquired at the four VOTE locations. Data processing involved image resizing and alignment, followed by rendering of three-dimensional (3D) volumetric models of the airways.

Results

Two patients were included in this study. Patient one had 18.4%, 20.9%, 72.3%, and 97.3% maximal obstruction at velum, oropharynx, tongue base, and epiglottis, while patient two had 40.2%, 41.4%, 8.0%, and 17.5% maximal obstruction at these regions, respectively. Three-dimensional reconstructions of patients' airways were also constructed from the OCT images.

Conclusion

This proof-of-concept study demonstrates the successful evaluation of pediatric airway during DISE using LR-OCT, which accurately identified sites and degrees of obstruction with respective 3D airway reconstruction.

Objective

Nasal airway obstruction (NAO) is caused by various disorders including nasal valve collapse (NVC). A bipolar radiofrequency (RF) device (VivAer®, Aerin Medical, Sunnyvale, CA) has been used to treat NAO through RF heat generation to the upper lateral cartilage (ULC). The purpose of this study is to measure temperature elevations in nasal tissue, using infrared (IR) radiometry to map the spatial and temporal evolution of temperature.

Study design

Experimental and computational.

Methods

Composite porcine nasal septum was harvested and sectioned (1 mm and 2 mm). The device was used to heat the cartilage in composite porcine septum. An IR camera (FLIR® ExaminIR, Teledyne, Wilsonville, OR) was used to image temperature on the back surface of the specimen. These data were incorporated into a heat transfer finite element model that also calculated tissue damage using Arrhenius rate process.

Results

IR temperature imaging showed peak back surface temperatures of 49.57°C and 42.21°C in 1 and 2 mm thick septums respectively. Temperature maps were generated demonstrating the temporal and spatial evolution of temperature. A finite element model generated temperature profiles with respect to time and depth. Rate process models using Arrhenius coefficients showed 30% chondrocyte death at 1 mm depth after 18 s of RF treatment.

Conclusion

The use of this device creates a thermal profile that may result in thermal injury to cartilage. Computational modeling suggests chondrocyte death extending as deep as 1.4 mm below the treatment surface. Further studies should be performed to improve dosimetry and optimize the heating process to reduce potential injury. Laryngoscope, 2023.

Mucociliary clearance is vital for preventing any foreign substances from entering the upper airway that can later develop into acute and/or chronic respiratory diseases. Therefore, it is essential to further advance our understanding of the mucociliary functions. Our lab has been able to make key developments in imaging cilia, specifically measuring cilia beat frequency, with phase-resolved Doppler optical coherence tomography. In this system, we have further developed the system by incorporating phase-resolved spectrally encoded interferometric microscopy (SIEM) system with an FDML laser with MHz sweep rate to image cilia with higher accuracy and to minimize motion artifacts. In addition, we have designed a compact handheld probe system with a GRIN lens for easier in vivo imaging. The development of this system will allow us to further investigate cilia dynamics and ultimately utilize the system for clinical applications.