Particulate matter exposure is associated with increased inflammatory cytokines and eosinophils in chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is thought to result from complex interactions between the host immune system, microbiota, and environmental exposures. Currently, there is limited data regarding the impact of ambient particulate matter ≤2.5 μm in diameter (PM2.5) in the pathogenesis of CRS, despite evidence linking PM2.5 to other respiratory diseases. We hypothesized that PM2.5 may result in differential cytokine patterns that could inform our mechanistic understanding of the effect of environmental factors on CRS.

METHODS

We conducted an analysis of data prospectively collected from 308 CRS patients undergoing endoscopic sinus surgery. Cytokines were quantified in intraoperative mucus specimens using a multiplex flow cytometric bead assay. Clinical and demographic data including zip codes were extracted and used to obtain tract-level income and rurality measures. A spatiotemporal machine learning model was used to estimate daily PM2.5 levels for the year prior to each patient's surgery date. Spearman correlations and regression analysis were performed to characterize the relationship between mucus cytokines and PM2.5. RESULTS: Several inflammatory cytokines including IL-2, IL-5/IL-13, IL-12, and 21 were significantly correlated with estimated average 6, 9, and 12-month preoperative PM2.5 levels. These relationships were maintained for most cytokines after adjusting for age, income, body mass index, rurality, polyps, asthma, and allergic rhinitis (AR) (p < .05). There were also higher odds of asthma (OR = 1.5, p = .01) and AR (OR = 1.48, p = .03) with increasing 12-month PM2.5 exposure. Higher tissue eosinophil counts were associated with increasing PM2.5 levels across multiple timeframes (p < .05).

CONCLUSIONS

Chronic PM2.5 exposure may be an independent risk factor for development of a mixed, type-2 dominant CRS inflammatory response.

Frailty is an independent predictor of postoperative rescue medication use after endoscopic sinus surgery

INTRODUCTION

The modified five-item frailty index (mFI-5) is a validated risk stratification tool with the ability to predict adverse outcomes following surgery. In this study, we sought to use mFI-5 to assess the potential relationship between unhealthy aging and postoperative endoscopic sinus surgery (ESS) outcomes.

METHODS

Patients who underwent sinus surgery at Vanderbilt between 2014 and 2018 were identified and assessed using the mFI-5, which is calculated based on the presence of five comorbidities: diabetes mellitus, hypertension requiring medication, chronic obstructive pulmonary disease, congestive heart failure, and non-independent functional status. Multivariate regression analyses were performed to quantify the association of mFI-5 score on need for rescue oral antibiotics, oral steroids, and antibiotic irrigations within 1 year following ESS, adjusting for relevant potential confounders.

RESULTS

Four hundred and three patients met inclusion criteria.  Within 6 months of surgery, 312 (77%) required rescue antibiotics, 243 (60%) required oral corticosteroids (OCS), and 31 (8%) initiated antibiotic irrigations. Increasing mFI-5 scores were significantly associated with higher postoperative use of rescue antibiotics (p < 0.0001), OCS (p = 0.032), and antibiotic irrigation (p < 0.0001). Frailty scores remained as an independent predictor of these outcomes after adjustment for age, polyp status, preoperative sinonasal outcomes test (SNOT-22) score, and revision surgery status.

CONCLUSIONS

Modified frailty scores may be a useful clinical tool to predict the need for postoperative rescue medication use after ESS.

Inflammatory characteristics of central compartment atopic disease

BACKGROUND

Central compartment atopic disease (CCAD) is an emerging phenotype of chronic rhinosinusitis with nasal polyposis (CRSwNP) characterized by prominent central nasal inflammatory changes. This study compares the inflammatory characteristics of CCAD relative to other phenotypes of CRSwNP.

METHODS

A cross-sectional analysis of data from a prospective clinical study was performed on patients with CRSwNP who were undergoing endoscopic sinus surgery (ESS). Patients with CCAD, aspirin-exacerbated respiratory disease (AERD), allergic fungal rhinosinusitis (AFRS), and non-typed CRSwNP (CRSwNP NOS) were included and mucus cytokine levels and demographic data were analyzed for each group. Chi-squared/Mann-Whitney U tests and partial least squares discriminant analysis (PLS-DA) were performed for comparison and classification.

RESULTS

A total of 253 patients were analyzed (CRSwNP, n = 137; AFRS, n = 50; AERD, n = 42; CCAD, n = 24). Patients with CCAD were the least likely to have comorbid asthma (p = 0.0004). The incidence of allergic rhinitis in CCAD patients did not vary significantly compared to patients with AFRS and AERD, but was higher compared to patients with CRSwNP NOS (p = 0.04). On univariate analysis, CCAD was characterized by less inflammatory burden, with reduced levels of interleukin 6 (IL-6), IL-8, interferon gamma (IFN-γ), and eotaxin relative to other groups and significantly lower type 2 cytokines (IL-5, IL-13) relative to both AERD and AFRS. These findings were supported by multivariate PLS-DA, which clustered CCAD patients into a relatively homogenous low-inflammatory cytokine profile.

CONCLUSIONS

CCAD has unique endotypic features compared to other patients with CRSwNP. The lower inflammatory burden may be reflective of a less severe variant of CRSwNP.

Hearing Vital Signs: Mobile Audiometry in the Emergency Department for Evaluation of Sudden Hearing Loss

Emergency departments (EDs) are a common location for patients to present with sudden hearing loss (SHL). Unfortunately, high-quality, rapid quantitative measurement of hearing loss is challenging. Herein, we aim to evaluate the accuracy of tablet-based audiometry in patients complaining of SHL. Prospective tablet-based testing was completed in the ED in patients complaining of SHL. Air conduction thresholds (ACTs) obtained via tablet-based audiometry were compared to same-day measurements with a clinical-grade audiometer. Hearing loss (HL) was defined as >20 dB ACT for any frequency. In participant-level analysis, 30+ dB HL in 3 consecutive frequencies was used to define SHL. In the ED, mobile audiogram ACTs were within 5 dB (77%) and 10 dB (89.6%) of those determined by conventional audiometry. The sensitivity and specificity for mobile audiometry to detect 3 or more consecutive thresholds with 30+ dB HL were 100% and 62.5%, respectively. Findings have implications for increasing access to high-quality audiometry.

Auditory Quality-of-Life Measures in Patients With Traumatic Brain Injury and Normal Pure Tone Audiometry

Auditory complaints are commonly reported following traumatic brain injury (TBI). However, few studies have examined patient-reported auditory symptomatology and quality-of-life metrics in individuals with TBI. We hypothesize that following TBI, individuals can experience auditory symptoms even with hearing thresholds in the normal range. Adult patients with normal auditory thresholds and a history of TBI were evaluated for subjective hearing loss, tinnitus, aural fullness, hyperacusis, and autophony. Hearing Handicap Inventory for Adults, Tinnitus Handicap Inventory, and Hyperacusis Questionnaire were administered. Thirty-one patients were prospectively recruited. Twenty-eight TBI participants (90%) reported ≥1 auditory symptoms at the time of survey intake. Mild to severe handicap in the Hearing Handicap Inventory for Adults and Tinnitus Handicap Inventory was reported in 71.4% and 40% of the participants with hearing loss and tinnitus, respectively. Hyperacusis handicap was considered significant in 41.1% of the participants who complained of hyperacusis and completed the survey. Despite normal hearing thresholds, individuals with TBI experience decrements in auditory quality-of-life metrics. Level of evidence: 3.

A 3D printed suturing trainer for medical students

BACKGROUND

Medical students must be able to suture competently upon graduation. To learn suturing technique, students must have access to practice materials. The purpose of this pilot study was to develop a novel suturing trainer and to evaluate its ability to provide realistic and accessible suturing practice. A cohort of senior students at one institution compared the device with standard suture-training media (porcine feet and sponges).

METHODS

Using 3D printing and silicone casting, a novel suturing trainer was developed and a cohort of senior medical students trialed the device in a standardised suturing workshop. Participants evaluated the novel suturing trainer, porcine feet and sponges for simulating human tissue with regard to: (i) tissue layers; (ii) tissue texture; (iii) ability to perform interrupted suturing; (iv) running subcuticular suturing; and (v) knot tying.

RESULTS

Compared with porcine feet and sponges, the suturing trainer had significantly higher mean scores (p < 0.001) for the simulation of human tissue layers and texture, as well as for the ability to facilitate the practice of interrupted suturing, running suturing and knot tying. All (n = 32) participants identified the silicone trainer as the best tool upon which to practice suturing, and 92% (n = 23) responded that their suturing skills would improve if the silicone trainer replaced porcine feet and sponges.

DISCUSSION

The silicone suturing device provides a more realistic and accessible suture learning experience than porcine feet and sponges. Further validation is required to assess its long-term effectiveness in medical education.

Long-term cochlear implantation outcomes in patients following head injury

OBJECTIVE

In cases of a severe to profound sensorineural hearing loss following head injury, the cochlear implant (CI) is the primary option for auditory rehabilitation. Few studies, however, have investigated long-term CI outcomes in patients following head trauma, including those without temporal bone fracture (TBF). Herein, the aim of this study is to examine CI outcomes following cases of head injury with and without TBF.

METHODS

Audiometric outcomes of patients who received a CI due to a head injury resulting in severe to profound hearing loss at two tertiary care hospitals were analyzed. Patients were divided into those who received a CI in a fractured temporal bone (group A, n = 11 patients corresponding to 15 ears) and those who received a CI in a non-fractured temporal bone (group B, n = 8 patients corresponding to nine ears). Primary outcomes included duration of deafness prior to CI and postoperative consonant-nucleus-constant whole word (CNC) scores.

RESULTS

Nineteen patients (84% male), corresponding to 24 CIs, were identified. Fifteen CI were performed on ears with TBF (group A), and nine CI were performed on ears without TBF (group B). No patients had an enlarged vestibular aqueduct (EVA). The mean duration of deafness was 5.7 and 11.3 years in group A and group B, respectively. The mean duration of CI follow-up (CI experience) was 6.5 years in group A and 2.1 years in group B. The overall mean postoperative CNC score for all subjects was 68.6% (±21.2%, n = 19 with CNC testing). There was no difference in CNC score between group A and group B (69.8% and 66% respectively, P = .639).

CONCLUSION

The study is among the largest series examining long-term outcomes of CI after head injury. CI is an effective method for auditory rehabilitation in patients after head injury.

LEVEL OF EVIDENCE

IV.

Review of Audiovestibular Symptoms Following Exposure to Acoustic and Electromagnetic Energy Outside Conventional Human Hearing

Objective: We aim to examine the existing literature on, and identify knowledge gaps in, the study of adverse animal and human audiovestibular effects from exposure to acoustic or electromagnetic waves that are outside of conventional human hearing. Design/Setting/Participants: A review was performed, which included searches of relevant MeSH terms using PubMed, Embase, and Scopus. Primary outcomes included documented auditory and/or vestibular signs or symptoms in animals or humans exposed to infrasound, ultrasound, radiofrequency, and magnetic resonance imaging. The references of these articles were then reviewed in order to identify primary sources and literature not captured by electronic search databases. Results: Infrasound and ultrasound acoustic waves have been described in the literature to result in audiovestibular symptomology following exposure. Technology emitting infrasound such as wind turbines and rocket engines have produced isolated reports of vestibular symptoms, including dizziness and nausea and auditory complaints, such as tinnitus following exposure. Occupational exposure to both low frequency and high frequency ultrasound has resulted in reports of wide-ranging audiovestibular symptoms, with less robust evidence of symptomology following modern-day exposure via new technology such as remote controls, automated door openers, and wireless phone chargers. Radiofrequency exposure has been linked to both auditory and vestibular dysfunction in animal models, with additional historical evidence of human audiovestibular disturbance following unquantifiable exposure. While several theories, such as the cavitation theory, have been postulated as a cause for symptomology, there is extremely limited knowledge of the pathophysiology behind the adverse effects that particular exposure frequencies, intensities, and durations have on animals and humans. This has created a knowledge gap in which much of our understanding is derived from retrospective examination of patients who develop symptoms after postulated exposures. Conclusion and Relevance: Evidence for adverse human audiovestibular symptomology following exposure to acoustic waves and electromagnetic energy outside the spectrum of human hearing is largely rooted in case series or small cohort studies. Further research on the pathogenesis of audiovestibular dysfunction following acoustic exposure to these frequencies is critical to understand reported symptoms.

Histopathological changes to the peripheral vestibular system following meningitic labyrinthitis

OBJECTIVE

While cochlear ossification is a common sequalae of meningitic labyrinthitis, less is known about the effects of meningitis on peripheral vestibular end organs. Herein, we investigate histopathologic changes in the peripheral vestibular system and cochlea in patients with a history of meningitic labyrinthitis.

METHODS

Temporal bone (TB) specimens from patients with a history of meningitis were evaluated and compared to age-matched controls. Specimens were evaluated by light microscopy and assessed for qualitative changes, including the presence of vestibular and/or cochlear endolymphatic hydrops, presence and location of inflammatory cells, new bone formation, and labyrinthitis ossificans; and quantitative changes, including Scarpa's ganglion neuron (ScGN) and spiral ganglion neuron (SGN) counts.

RESULTS

Fifteen TB from 10 individuals met inclusion and exclusion criteria. Presence of inflammatory cells and fibrous tissue was found in 5 TB. Of these, evidence of labyrinthitis ossificans was found in 2 TB. In the peripheral vestibular system, mild to severe degeneration of the vestibular membranous labyrinth was identified in 60% of cases (n = 9 TBs). There was a 21.2% decrease (range, 3%-64%) in the mean total count of ScGN in patients with meningitis, compared to age-matched controls. In the cochlea, there was a 45% decrease (range, 25.3%-80.9%) in the mean total count of SGN compared to age-matched controls (n = 14 TBs).

CONCLUSIONS

Otopathologic analysis of TB from patients with a history of meningitic labyrinthitis demonstrated distinct peripheral vestibular changes. Future research may help to delineate potential mechanisms for the observed otopathologic changes following meningitis.

LEVEL OF EVIDENCE

N/A.

Labyrinthine concussion: Historic otopathologic antecedents of a challenging diagnosis

OBJECTIVE

The term "labyrinthine concussion" has evolved to mean audiovestibular dysfunction in the absence of a temporal bone fracture (TBF). Despite a multitude of case descriptions of labyrinthine concussion, the precise pathophysiology remains poorly understood. Herein, we explore the historical otopathologic underpinnings of the diagnosis of labyrinthine concussion with a focus on the auditory pathway during the late 19th to the mid-20th centuries and conclude with a discussion of its contemporary relevance.

METHODS AND DATA SOURCES

A review of primary and secondary medical sources written in English, German, and French on otopathology labyrinthine concussion studies from the late-19th to the mid-20th centuries.

RESULTS

Around the turn of the 20th century, otopathologists identified histologic changes in the temporal bones of individuals that sustained head injury without TBFs. Based on these otopathologic findings in humans, early experiments investigating the pathophysiology of labyrinthine concussion were performed in animals through either the delivery of blows to the head or direct introduction of a pressure wave into the labyrinthine fluid. Collectively, otopathologists hypothesized that predominant mechanisms for labyrinthine concussion included inner ear hemorrhage, cochleovestibular nerve traction injury, direct damage from a labyrinthine fluid pressure wave, or vasomotor dysfunction.

CONCLUSION

Historical study shows a variety of inner ear pathologies potentially responsible for auditory dysfunction following head injury. Understanding the history and otopathology of labyrinthine concussion may help clinicians focus on new pathways toward novel research and improved patient care.

Transcanal Computed Tomography Views for Transcanal Endoscopic Lateral Skull Base Surgery: Pilot Cadaveric Study

Objective  Transcanal endoscopic operative approaches provide for a minimally invasive surgical portal to the lateral skull base. Traditional preoperative imaging evaluation involves computed tomography (CT) acquisition in the axial and coronal planes that are not optimized for the transcanal surgical corridor. Herein, we describe a novel CT-based "transcanal view" for preoperative surgical planning and intraoperative navigation. Study Design  Present study is a cadaveric imaging study. Methods  Cadaveric temporal bones ( n  = 6) from three specimens underwent high-resolution CT (0.625 mm slice thickness). Using three-dimensional (3D) Slicer 4.8, reformatted "transcanal" views in the plane of the external auditory canal (EAC) were created. Axial and coronal reformats were used to compare and measure distances between anatomic structures in the plane of the EAC. Results  The degree of oblique tilt for transcanal CT reformats was 6.67 ± 1.78 degrees to align the EAC in axial and coronal planes. Anticipated critical landmarks were identified easily using the transcanal view. Mean values were 8.68 ± 0.38 mm for annulus diameter, 9.5 ± 0.93 mm for isthmus diameter, 10.27 ± 0.73 mm for distance between annulus and isthmus, 2.95 ± 0.13 mm for distance between annulus and stapes capitulum, 5.12 ± 0.35 mm for distance between annulus and mastoid facial nerve, and 19.54 ± 1.22 mm for EAC length. Conclusion  This study is the first to illustrate a novel "transcanal" CT sequence intended for endoscopic lateral skull base surgery. Future studies may address how incorporation of a transcanal CT reformat may influence surgical decision making.

Peripheral Vestibular Organ Degeneration After Temporal Bone Fracture: A Human Otopathology Study

OBJECTIVES/HYPOTHESIS

Vestibular symptoms are a common sequela of temporal bone fractures (TBFs). The mechanisms of injury to the peripheral vestibular system following TBF, however, are not well described. Herein, we aimed to investigate the histopathology of the peripheral vestibular system in patients who sustained TBFs.

STUDY DESIGN

Retrospective human specimen analysis.

METHODS

Specimens from the National Temporal Bone Pathology Registry with (cases) and without (controls) TBFs were evaluated. Specimens were analyzed by light microscopy for vestibular hair cell and/or dendritic degeneration, presence of endolymphatic hydrops, blockage of the endolymphatic duct, and number of Scarpa ganglion cells (ScGCs) in the superior and inferior vestibular nerves.

RESULTS

Seven temporal bones (TBs) from five individuals with TBFs, and seven TBs from six age-matched individuals without a history of head injury met inclusion and exclusion criteria. All fractures involved the otic capsule. Severe degeneration of the cristae was identified in the semicircular canals in all TBF cases. The utricular and saccular maculae showed mild to severe degeneration in the TBF cases. Vestibular hydrops (n = 2 TBs) and blockage of the endolymphatic duct (n = 3 TBs) were also present in the TBF cases. There was a decrease of 52.6% in the mean total ScGC count in the TBF cases (n = 3 TBs) compared to age-matched controls (n = 7 TBs, P = .015). There was a mean loss of 53% of the ScGCs in the superior vestibular nerve and a mean loss of 52.3% of the ScGCs in the inferior vestibular nerve compared to age-matched controls (P = .033 and P = .021, respectively).

CONCLUSIONS

In a cohort of patients with TBFs, there were distinct peripheral vestibular changes including reduction of ScGCs.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:752-760, 2020.