The human middle ear in motion: 3D visualization and quantification using dynamic synchrotron-based X-ray imaging

The characterization of the vibrations of the middle ear ossicles during sound transmission is a focal point in clinical research. However, the small size of the structures, their micrometer-scale movement, and the deep-seated position of the middle ear within the temporal bone make these types of measurements extremely challenging. In this work, dynamic synchrotron-based X-ray phase-contrast microtomography is used on acoustically stimulated intact human ears, allowing for the three-dimensional visualization of entire human eardrums and ossicular chains in motion. A post-gating algorithm is used to temporally resolve the fast micromotions at 128 Hz, coupled with a high-throughput pipeline to process the large tomographic datasets. Seven ex-vivo fresh-frozen human temporal bones in healthy conditions are studied, and the rigid body motions of the ossicles are quantitatively delineated. Clinically relevant regions of the ossicular chain are tracked in 3D, and the amplitudes of their displacement are computed for two acoustic stimuli.

Ossicular joint histopathology in cases of age-related hearing loss

Objectives

Age-related hearing loss (presbycusis) is a prevalent condition traditionally attributed to inner ear dysfunction. Little is known about age-related changes in the ossicular joints or their contribution to presbycusis. Herein, we performed an otopathologic evaluation of the ossicular joints in cases of presbycusis without a clear sensorineural explanation.

Methods

Histopathologic analysis of the incudomallear (IM) and incudostapedial (IS) joints was performed in specimens from the National Temporal Bone Registry with audiometrically confirmed presbycusis but without histologically observed sensorineural, strial, or mixed features; deemed cases of "indeterminate" presbycusis. Specimens identified as "indeterminate" presbycusis (IP, n = 18) were compared to specimens with histologically confirmed sensorineural presbycusis (n = 16) and strial presbycusis (n = 11). Presbycutic specimens were also compared to age-matched controls (n = 9) and young controls (n = 14).

Results

The synovial space at the center of the IM joint was wider in the IP group (194 ± 36.8 μm) compared to age-matched controls (138 ± 36.5 μm), young controls (149 ± 32.2 μm), and ears with sensorineural presbycusis (148 ± 52.7 μm) (p < .05). The synovial space within the IS joint was wider in the IP group (105 ± 33.0 μm) when compared to age-matched controls (57.9 ± 13.1 μm) and ears with sensorineural presbycusis (62.3 ± 31.2 μm) (p < .05).

Conclusion

IP ears have wider IM and IS joints when compared to ears with sensorineural presbycusis and age-matched controls. Findings point to a potential middle ear source of high frequency conductive hearing loss in a subset of presbycutic ears.

Level of Evidence

Retrospective study.

Human otopathology in scleroderma

Objective

Scleroderma is a complex chronic progressive immune-mediated disease that causes fibrosis of the skin and internal organs, and vasculopathy.Ear involvement has been poorly studied in patients with scleroderma. Vasculitic and autoimmune mechanisms are considered as possible etiologies on hearing impairment, however, this etiology still unclear.Herein, we reviewed three cases of scleroderma from a temporal bone repository.

Methods

The national temporal bone database was reviewed for cases with scleroderma. Clinical case review and correlative otopathologic analysis. Middle and inner ear otopathologic analysis was performed following hematoxylin and eosin staining under light microscopy. Findings were compared to three age-matched controls.

Results

Two patients (three cases) with a history of serologically confirmed scleroderma were identified. Both individuals reported tinnitus and demonstrated bilateral moderate to severe down-sloping sensorineural hearing loss on audiometry. Histologically, the incudomallear joint space was diminished and ossicles appeared demineralized. A loss of hyaline cartilage, and obliteration of the incudomallear and incudostapedial joint synovial spaces was observed. Decreased caliber and intimal hyperplasia of arteries adjacent to ossicles was also identified. Mild diffuse atrophy of stria vascularis in the middle and apical turns of cochlea were found. Hair cell populations were normal. Total spiral ganglion neurons were lower in cases of scleroderma (range 29%-51%) compared to age-matched controls.

Conclusion

Fibrosis, inflammation, and vascular changes were observed in the middle and inner ear in patients with scleroderma. Findings have implications for understanding hearing and vestibular dysfunction in this patient population.

Level of evidence

Retrospective study.

Primary Sarcoidosis of the Temporal Bone a Clinical Pathologic Correlation

Objective

This report describes a case of sarcoidosis that presented as a lytic bone lesion in the squamous part of the temporal bone.

Patients

A 64-year-old woman presented with right-sided aural fullness, pulsatile tinnitus, and intermittent otalgia.

Interventions

CT and MRI were performed without contrast and suggested an osseodestructive, lytic bone lesion. An excisional biopsy was performed, showing granulomatous infiltration suggestive of osseous sarcoidosis.

Main Outcome Measures

Removal of mass and resolution of symptoms.

Results

Initial findings from patient imaging suggested a lytic bone lesion. An excisional biopsy was required for diagnosis and was performed with little patient morbidity. Biopsy findings showed granulomatous infiltration suggestive of osseous sarcoidosis. Osseous involvement of sarcoidosis is a rare manifestation and typically occurs secondary to other disease manifestations. After the removal of the mass and a short unrelated course of steroids, the patient's symptoms resolved.

Conclusions

Sarcoidosis should be added to the differential diagnosis of lytic bone lesions in the temporal bone.

Measurements of ear-canal geometry from high-resolution CT scans of human adult ears

Description of the ear canal's geometry is essential for describing peripheral sound flow, yet physical measurements of the canal's geometry are lacking and recent measurements suggest that older-adult-canal areas are systematically larger than previously assumed. Methods to measure ear-canal geometry from multi-planar reconstructions of high-resolution CT images were developed and applied to 66 ears from 47 subjects, ages 18-90 years. The canal's termination, central axis, entrance, and first bend were identified based on objective definitions, and the canal's cross-sectional area was measured along its canal's central axis in 1-2 mm increments. In general, left and right ears from a given subject were far more similar than measurements across subjects, where areas varied by factors of 2-3 at many locations. The canal areas varied systematically with age cohort at the first-bend location, where canal-based measurement probes likely sit; young adults (18-30 years) had an average area of 44mm² whereas older adults (61-90 years) had a significantly larger average area of 69mm². Across all subjects ages 18-90, measured means ± standard deviations included: canals termination area at the tympanic annulus 56±8mm²; area at the canal's first bend 53±18mm²; area at the canal's entrance 97±24mm²; and canal length 31.4±3.1mm².

Design of medical tympanostomy conduits with selective fluid transport properties

Implantable tubes, shunts, and other medical conduits are crucial for treating a wide range of conditions from ears and eyes to brain and liver but often impose serious risks of device infection, obstruction, migration, unreliable function, and tissue damage. Efforts to alleviate these complications remain at an impasse because of fundamentally conflicting design requirements: Millimeter-scale size is required to minimize invasiveness but exacerbates occlusion and malfunction. Here, we present a rational design strategy that reconciles these trade-offs in an implantable tube that is even smaller than the current standard of care. Using tympanostomy tubes (ear tubes) as an exemplary case, we developed an iterative screening algorithm and show how unique curved lumen geometries of the liquid-infused conduit can be designed to co-optimize drug delivery, effusion drainage, water resistance, and biocontamination/ingrowth prevention in a single subcapillary-length-scale device. Through extensive in vitro studies, we demonstrate that the engineered tubes enabled selective uni- and bidirectional fluid transport; nearly eliminated adhesion and growth of common pathogenic bacteria, blood, and cells; and prevented tissue ingrowth. The engineered tubes also enabled complete eardrum healing and hearing preservation and exhibited more efficient and rapid antibiotic delivery to the middle ear in healthy chinchillas compared with current tympanostomy tubes, without resulting in ototoxicity at up to 24 weeks. The design principle and optimization algorithm presented here may enable tubes to be customized for a wide range of patient needs.

Characterization and Clinical Use of Bone Conduction Transducers at Extended High Frequencies

Measurement of bone conduction (BC) hearing thresholds at extended high frequencies (EHF; above 8 kHz) is of clinical interest but is technically complicated by limitations in standard BC transducer output, a lack of calibration standards and sparse clinical data from human subjects. A recently described calibration scheme using an artificial mastoid and interposed accelerometer is applied in this study to characterize and compare acceleration and computed force outputs over the 4-20 kHz range of two standard BC transducers: the RadioEar® B71 and B81, as well as two non-standard, commercially available BC transducers: the Tascam® HP-F200 and the Aftershokz® AS400. Measures of linear output growth, harmonic distortion and acoustic radiation are assessed and compared across devices. A maximum linear input voltage is established for each BC transducer using measurements of linear output growth and total harmonic distortion. At maximum linear input level, the Tascam shows superior force output by 25 to 40 dB above 8 kHz and the widest dynamic EHF range. Acoustic radiation per output force was lowest for the Tascam, whereas the AS400 behaved more like an air conduction earphone than a force generator. In a cohort of 15 normal hearing volunteers, BC thresholds, measured with the Tascam and reported in dB re 1 rms μN, were consistent with historical measures of EHF BC thresholds in similar subjects using an alternative BC transducer.

Evaluating the accuracy of speech to text applications for cochlear implant candidates during COVID-19

OBJECTIVES

Universal mask wearing due to COVID-19 has introduced barriers to clear communication. In hearing impaired individuals this can impact informed surgical consent. For cochlear implant candidates, who do not rely on sign language, real-time transcription with a stenographer (CART) is the gold-standard in assistive technologies. If CART is not available, speech to text (STT) applications have been advertised as solutions, but their transcription accuracy with or without an N95 mask is not well-established. Herein, we sought to investigate the transcription accuracy of three STT solutions for iPhone and compare their performance to the CART service at our institution.

METHODS

Three native English speakers and three non-native English speakers read two passages (a cochlear implant consent and the non-medical 'Rainbow passage') with and without an N95 mask. Error rates from the comparison of the transcript (from either the STT app or CART) with the original passage were calculated.

RESULTS

The CART service had the lowest error rate of all testing conditions (4.79-7.14%). Ava 24/7 (15.0 ± 9.49%) and the iPhone dictation (15.6 ± 6.65%) had significantly lower average error rates than the Live Transcribe (37.7 ± 20.3%) (P < 0.0001) application. Neither the presence of an N95 nor the type of passage had a statistically significant impact on the error rate.

CONCLUSION

CART should be used to augment communication with patients who are hard of hearing. If CART is not available, a STT application such as Ava 24/7 or the native iPhone dictation application may be considered, even in the context of medical terminology.

Educational Quality of YouTube Cholesteatoma Surgery Videos: Areas for Improvement

Otolaryngology surgical education continues to evolve where trainees increasingly use videos to learn technical skills. Trainees commonly use YouTube, but no study to date has evaluated the educational quality (EQ) of otologic surgical videos on YouTube. We aim to assess the EQ of cholesteatoma surgical videos. Cholesteatoma surgical videos were queried using YouTube search terms, assessed using LAParoscopic surgery Video Educational GuidelineS (LAP-VEGaS), a validated assessment tool for publication, and categorized into low (0-6), medium (7-12), and high (13-18) EQ groups. In total, 74 videos were identified (mean LAP-VEGaS score = 9.6 ± 4.0) and 44.6% had medium EQ. Videos commonly lacked graphic aids to highlight anatomy (71.6%) and postprocedural outcomes (68.9%). LAP-VEGaS scores were greater in videos originating from US surgeons compared to non-US surgeons (12.4 ± 3.4 vs 8.0 ± 3.5; P < .001). Our study highlights that otolaryngology trainees may experience difficulty finding high-EQ cholesteatoma surgery videos on YouTube. Areas for improved EQ content are discussed. Level of evidence: IV.

Ex vivo transtympanic permeation of the liposome encapsulated S. pneumoniae endolysin MSlys

An increase in bacterial resistance to systemic antibiotics has sparked interest into alternative antimicrobial compounds as well as methods for effective local, non-invasive drug delivery. Topical treatments, however, may be hindered by the presence of biological barriers, such as the tympanic membrane in the case of otitis media. Herein, the transtympanic permeation ability of liposomes loaded with the pneumococcal endolysin MSlys and of free MSlys was evaluated ex vivo. MSlys loaded in PEGylated liposomes showed an increased permeation across human tympanic membranes, as compared to its free form, being able to reduce the pneumococcal cell load after 2 h of permeation. However, antipneumococcal activity was no longer detected after 4 h of permeation and hydrolysis of the endolysin was observed after an extended incubation time (≥48 h). This work provides a first assessment of a successful, non-invasive delivery method for endolysins across an intact tympanic membrane. Findings have implications for non-systemic, local treatment of otitis media.

Methods for the calibration of bone conduction transducers at frequencies from 5 to 20 kHz

Techniques for standardizing the output of bone conduction transducers over the 5-20 kHz range are presented. The techniques include definitions of the standard artificial mastoid (AM) impedance and force sensitivity in that high-frequency range using an impedance head coupled to a vibration source. The AM impedance is shown to vary with the contact area of the vibration source. The AM force sensitivity does not vary with the contact area but does exhibit sharp frequency dependences over the 14-20 kHz range. The sharp frequency dependence complicates the use of the AM force sensor as a stand-alone calibration device at these high frequencies. An alternative calibration scheme that uses an accelerometer interposed between the vibrator and the AM impedance is described. Comparisons of the two schemes demonstrate that the accelerometer method produces more consistent results. Comparisons of the force and acceleration output of one bone conduction vibrator at high frequencies suggest those outputs depend on the driven load. The loads used in the two calibration schemes are compared to what is known of the impedance of the skin-covered head.

Assessment of Sudden Sensorineural Hearing Loss After COVID-19 Vaccination

IMPORTANCE

Emerging reports of sudden sensorineural hearing loss (SSNHL) after COVID-19 vaccination within the otolaryngological community and the public have raised concern about a possible association between COVID-19 vaccination and the development of SSNHL.

OBJECTIVE

To examine the potential association between COVID-19 vaccination and SSNHL.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study and case series involved an up-to-date population-based analysis of 555 incident reports of probable SSNHL in the Centers for Disease Control and Prevention Vaccine Adverse Events Reporting System (VAERS) over the first 7 months of the US vaccination campaign (December 14, 2020, through July 16, 2021). In addition, data from a multi-institutional retrospective case series of 21 patients who developed SSNHL after COVID-19 vaccination were analyzed. The study included all adults experiencing SSNHL within 3 weeks of COVID-19 vaccination who submitted reports to VAERS and consecutive adult patients presenting to 2 tertiary care centers and 1 community practice in the US who were diagnosed with SSNHL within 3 weeks of COVID-19 vaccination.

EXPOSURES

Receipt of a COVID-19 vaccine produced by any of the 3 vaccine manufacturers (Pfizer-BioNTech, Moderna, or Janssen/Johnson & Johnson) used in the US.

MAIN OUTCOMES AND MEASURES

Incidence of reports of SSNHL after COVID-19 vaccination recorded in VAERS and clinical characteristics of adult patients presenting with SSNHL after COVID-19 vaccination.

RESULTS

A total of 555 incident reports in VAERS (mean patient age, 54 years [range, 15-93 years]; 305 women [55.0%]; data on race and ethnicity not available in VAERS) met the definition of probable SSNHL (mean time to onset, 6 days [range, 0-21 days]) over the period investigated, representing an annualized incidence estimate of 0.6 to 28.0 cases of SSNHL per 100 000 people per year. The rate of incident reports of SSNHL was similar across all 3 vaccine manufacturers (0.16 cases per 100 000 doses for both Pfizer-BioNTech and Moderna vaccines, and 0.22 cases per 100 000 doses for Janssen/Johnson & Johnson vaccine). The case series included 21 patients (mean age, 61 years [range, 23-92 years]; 13 women [61.9%]) with SSNHL, with a mean time to onset of 6 days (range, 0-15 days). Patients were heterogeneous with respect to clinical and demographic characteristics. Preexisting autoimmune disease was present in 6 patients (28.6%). Of the 14 patients with posttreatment audiometric data, 8 (57.1%) experienced improvement after receiving treatment. One patient experienced SSNHL 14 days after receiving each dose of the Pfizer-BioNTech vaccine.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, findings from an updated analysis of VAERS data and a case series of patients who experienced SSNHL after COVID-19 vaccination did not suggest an association between COVID-19 vaccination and an increased incidence of hearing loss compared with the expected incidence in the general population.

"Transcanal view" computed tomography reformat: Applications for transcanal endoscopic ear surgery

PURPOSE

Transcanal endoscopic ear surgery (TEES) is an increasingly used surgical approach for otologic surgeries, but no en face preoperative imaging format currently exists. We aim to assess the utility of a transcanal high resolution computed tomography (HRCT) reformat suitable for TEES preoperative planning.

MATERIALS AND METHODS

Preoperative HRCTs of patients with middle ear pathologies (cholesteatoma, otosclerosis, and glomus tympanicum) who underwent TEES were obtained. Axial image series were rotated and reformatted -90 or +90 degrees for left and right ear surgeries, respectively, where additional rotation along the left-right axis was performed to align the transcanal series with the plane of the external auditory canal. Quantitative measurements of middle ear structures were recorded. Consecutive transcanal reformatted sections were then reviewed to identify critical middle ear anatomy and pathology with corresponding TEES cases.

RESULTS

The aforementioned methodology was used to create three transcanal view HRCTs. The mean left-right axis degree of rotation was 4.0 ± 2.2 degrees. In the cholesteatoma transcanal HRCT, areas of cholesteatoma involvement in middle ear compartments (e.g. epitympanum) and eroded ossicles were successfully identified in the corresponding case. In the otosclerosis transcanal HRCT, areas for potential otosclerotic involvement were visualized such as the round window as well as a low-hanging facial nerve. In the glomus tympanicum transcanal HRCT, the span of the glomus tympanicum was successfully visualized in addition to a high riding jugular bulb.

CONCLUSION

A transcanal HRCT reformat may aid preoperative planning for middle ear pathologies. This novel reformat may help highlight patient-specific anatomy.

A Subset of Intracanalicular Vestibular Schwannomas Demonstrates Minimal Growth Over a 10-Year Period

OBJECTIVE

Vestibular schwannomas (VS) commonly undergo magnetic resonance imaging (MRI) surveillance, but long-term data to support the ideal frequency is limited. Herein, we aim to investigate intracanalicular VS growth predictors and long-term growth rates (GR).

STUDY DESIGN

Retrospective chart review.

SETTING

Two tertiary care centers.

PATIENTS

Sporadic intracanalicular VS with initial conservative management and at least two sequential MRIs.

INTERVENTION

Serial MRI.

MAIN OUTCOME MEASURES

VS were categorized by baseline internal auditory canal tertile sublocalization (fundus, midpoint, porus) and size (≤100, 100-200, >200 mm3). Throughout follow-up, volumetric GR (mm3/yr) were determined (baseline-3 yrs, 3-5 yrs, 5-10 yrs) and treatment rates were assessed.

RESULTS

Ninety-nine intracanalicular VS were identified (mean follow-up of 6.1 ± 4.5 yrs). Mean GR before 5-year follow-up were comparable for baseline tertile involvement and size. After 5-year follow-up, mean GR of VS involving the fundus at baseline were lower than those involving the midpoint and fundus (6.17 ± 21.16 and 119.74 ± 117.57 mm3/yr, respectively; p = 0.034). Mean GR of VS with less than or equal to 100 mm3 at baseline (-7.29 ± 25.44 mm3/yr) were lower than those with 100 to 200 mm3 (86.55 ± 103.99 mm3/yr; p = 0.011) and more than 200 mm3 (45.70 ± 35.71 mm3/yr; p = 0.031). Vestibular schwannomas involving the midpoint and fundus had greater treatment rates compared with VS involving only the fundus (p < 0.001).

CONCLUSIONS

Baseline tertile involvement and size may predict long-term intracanalicular VS growth where fundal tumors or those less than or equal to 100 mm3 exhibit little long-term growth. Extending surveillance after 5-year follow-up may be reasonable for fundal VS.

Does stapedotomy improve high frequency conductive hearing?

OBJECTIVES

Stapedotomy is performed to address conductive hearing deficits. While hearing thresholds reliably improve at low frequencies (LF), conductive outcomes at high frequencies (HF) are less reliable and have not been well described. Herein, we evaluate post-operative HF air-bone gap (ABG) changes and measure HF air conduction (AC) thresholds changes as a function of frequency.

METHODS

Retrospective review of patients who underwent primary stapedotomy with incus wire piston prosthesis between January 2016 and May 2020. Pre- and postoperative audiograms were evaluated. LF ABG was calculated as the mean ABG of thresholds at 250, 500, and 1000 Hz. HF ABG was calculated at 4 kHz.

RESULTS

Forty-six cases met criteria. Mean age at surgery was 54.0 ± 11.7 years. The LF mean preoperative ABG was 36.9 ± 11.0 dB and postoperatively this significantly reduced to 9.35 ± 6.76 dB, (P < .001). The HF mean preoperative ABG was 31.1 ± 14.4 dB and postoperatively, this also significantly reduced to 14.5 ± 12.3 dB, (P < .001). The magnitude of LF ABG closure was over 1.5 times the magnitude of HF ABG closure (P < .001). The gain in AC decreased with increasing frequency (P < .001).

CONCLUSION

Hearing improvement following stapedotomy is greater at low than high frequencies. Postoperative air bone gaps persist at 4 kHz. Further biomechanical and histopathologic work is necessary to localize postoperative high frequency conductive hearing deficits and improve stapedotomy hearing outcomes.

LEVEL OF EVIDENCE

4, retrospective study.

Mechanics of Total Drum Replacement Tympanoplasty Studied With Wideband Acoustic Immittance

OBJECTIVE

Poor hearing outcomes often persist following total drum replacement tympanoplasty. To understand the mechanics of the reconstructed eardrum, we measured wideband acoustic immittance and compared the mechanical characteristics of fascia-grafted ears with the normal tympanic membrane.

STUDY DESIGN

Prospective comparison study.

SETTING

Tertiary care center.

METHODS

Patients who underwent uncomplicated total drum replacement with temporalis fascia grafts were identified. Ears with healed grafts, an aerated middle ear, and no other conductive abnormalities were included. All patients underwent pre- and postoperative audiometry. Wideband acoustic immittance was measured with absorbance and impedance computed. Fascia-grafted ears were compared with normal unoperated ears.

RESULTS

Eleven fascia-grafted ears without complications were included. Postoperatively, the median air-bone gap was 15 dB (250-4000 Hz), with variation across frequency and between ears. Fifty-six control ears were included. Absorbance of fascia-grafted ears was significantly lower than that of normal ears at 1 to 4 kHz (P < .05) but similar below 1 kHz. Impedance magnitude demonstrated deeper and sharper resonant notches in fascia-grafted ears than normal ears (P < .05), suggesting lower mechanical resistance of the fascia graft.

CONCLUSION

The mechanics of fascia-grafted ears differ from the normal tympanic membrane by having lower absorbance at mid- to high frequencies and thus poor sound transmission. The lower resistance in fascia-grafted ears may be due to poor coupling of the graft to the malleus. To improve sound transmission, grafts for tympanic membrane reconstructions would benefit from refined mechanical properties.

Assessment of Preoperative Functional Status Prior to Major Head and Neck Surgery: A Pilot Study

OBJECTIVE

To demonstrate feasibility of a recently developed preoperative assessment tool, the Vulnerable Elders Surgical Pathways and Outcomes Analysis (VESPA), to characterize the baseline functional status of patients undergoing major head and neck surgery and to examine the relationship between preoperative functional status and postoperative outcomes.

STUDY DESIGN

Case series with planned data collection.

SETTING

Two tertiary care academic hospitals.

METHODS

The VESPA was administered prospectively in the preoperative setting. Data on patient demographics, ablative and reconstructive procedures, and outcomes including total length of stay, discharge disposition, delay in discharge, or complex discharge planning (delay or change in disposition) were collected via retrospective chart review. VESPA scores were calculated and risk categories were used to estimate risk of adverse postoperative outcomes using multivariate logistic regression for categorical outcomes and linear regression for continuous variables.

RESULTS

Fifty-eight patients met study inclusion criteria. The mean (SD) age was 66.4 (11.9) years, and 58.4% of patients were male. Nearly one-fourth described preoperative difficulty in either a basic or instrumental activity of daily living, and 17% were classified as low functional status (ie, high risk) according to the VESPA. Low functional status did not independently predict length of stay but was associated with delayed discharge (odds ratio [OR], 5.0; 95% CI, 1.2-21.3; P = .030) and complex discharge planning (OR, 5.7; 95% CI, 1.34-24.2; P = .018).

CONCLUSION

The VESPA can identify major head and neck surgical patients with low preoperative functional status who may be at risk for delayed or complex discharge planning. These patients may benefit from enhanced preoperative counseling and more comprehensive discharge preparation.

Further Research Needed to Understand Relationship Between Tubarial Glands and Eustachian Tube Dysfunction

The pathophysiology of eustachian tube dysfunction (ETD) remains poorly characterized, and it may result in significant patient morbidity. A recent study has identified a collection of previously unidentified salivary glands in the nasopharynx that overlay the torus tubarius. While salivary gland tissue has been described in the nasopharynx, the newly discovered salivary gland tissue has been denoted tubarial glands (TGs) and theorized to be a distinct organ. The TGs have been suggested to aid in lubrication of the oropharynx and nasopharynx. However, the exact clinical significance of TGs is unknown. Given the proximity of the TG to the eustachian tube, it is possible that the TGs may be related to the development of ETD. Future studies of the TGs and related pathophysiology may improve approaches to developing future ETD treatments.

Histopathology of the Incudomalleolar Joint in Cases of "Indeterminate" Presbycusis

LEVEL OF EVIDENCE

Retrospective study.

Do high-frequency air-bone gaps persist after ossiculoplasty?

OBJECTIVES

Conventional reporting of postoperative hearing outcomes utilizes a pure-tone averaged air-bone gap (ABG) that is biased toward low frequencies. Consequently, a high-frequency ABG after otologic surgery may go unnoticed. In this study, we evaluate changes in low- and high-frequency ABG following ossiculoplasty.

STUDY DESIGN

Retrospective review.

SUBJECTS AND SETTING

Consecutive series of patients who underwent ossiculoplasty at a single tertiary care center. Patients with pre- and postoperative audiograms were included.

METHODS

Low-frequency ABG was calculated as the mean ABG at 250, 500, and 1000 Hz. High-frequency ABG was calculated at 4 kHz. Pre- and postoperative ABGs were compared.

RESULTS

Thirty-seven consecutive patients were included. Mean age at surgery was 38 years (range, 7-77 years). Reconstruction materials included: cartilage (N = 4), hydroxyapatite cement (N = 5), and partial or total ossicular replacement prostheses (N = 20 and N = 8, respectively). Postoperatively, the mean low-frequency ABG improved by 11.9 ± 15.1 dB (P < .0001) and the mean high-frequency ABG improved by 5.9 ± 16.0 dB (P = .030). Low-frequency ABG closure was significantly larger than high-frequency ABG closure (P = .007). Mean postoperative persistent high-frequency ABG was 22.0 ± 13.8 dB.

CONCLUSION

In this series, ossiculoplasty improved ABG across all frequencies, but greater improvements were observed at low frequencies when compared to high frequency. Current reporting standards may not identify persistent high-frequency ABG. Additional study of the mechanisms of high-frequency sound conduction in reconstructed middle ears is needed to improve high-frequency hearing outcomes in ossiculoplasty.

LEVEL OF EVIDENCE

Level 4.

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.

A Systematic Review of Nonautologous Graft Materials Used in Human Tympanoplasty

OBJECTIVES

Nonautologous graft materials may solve several dilemmas in tympanoplasty by obviating the need for graft harvest, facilitating consistent wound healing, and permitting graft placement in the clinical setting. Prior studies of nonautologous grafts in humans have shown variable outcomes. In this systematic review, we aim to 1) summarize clinical outcomes and 2) discuss limitations in the literature regarding nonautologous grafts for tympanoplasty in humans.

METHODS

A literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. The study size, etiology and duration of perforation, type of nonautologous graft, and postoperative closure rate were assessed.

RESULTS

The PRISMA approach yielded 61 articles, including 3,247 ears that met inclusion criteria. Studies evaluated nonautologous grafts including paper patch, gelatin sponge, growth factors, porcine small-intestinal submucosa, among others. Traumatic perforations (62.3%) were most commonly studied, whereas postinfectious perforations (31.9%) and other etiologies (5.8%) comprised a minority of cases. Acute perforations of <8 weeks duration constituted just over half of all treated ears. Overall closure rate was 82.1%, with significantly higher closure rates in acute (89.9%) versus chronic perforations (64.9%, P < .01), regardless of material. A median postoperative air-bone gap of 5.6 dB was found in the 23% of studies reporting this metric.

CONCLUSIONS

The majority of publications reviewing nonautologous materials in tympanoplasty evaluate acute or traumatic perforations, and few rigorously report hearing outcomes. Given available data, porcine submucosa and basic fibroblast growth factor may hold promise for chronic perforation closure. Future studies should report closure rates and hearing outcomes in perforations >8 weeks duration. Laryngoscope, 131:392-400, 2021.

Effect of Powered Air-Purifying Respirators on Speech Recognition Among Health Care Workers

Powered air-purifying respirators (PAPRs) are used as personalized protective equipment for health care personnel. PAPRs offer health care workers added protection when dealing with patients who have high-risk infectious disease such as COVID-19. Unfortunately, PAPRs can produce notable levels of background noise. We hypothesize that PAPR use may be associated with increased hearing thresholds and impaired word discrimination and may ultimately have a negative impact on effective communication. Herein, we (1) determined sound levels generated by PAPRs and (2) measured hearing thresholds and word discrimination with and without operational PAPRs. All participants had normal hearing. When the PAPR was operational, mean ± SD thresholds increased from 4.5 ± 3.6 to 38.6 ± 5.6 dB HL ( P < .001). Word discrimination dropped from 100% in all participants in quiet to a mean 48% ± 14% with operational PAPR ( P < .001). Thus, we find that use of PAPR hoods results in hearing impairment comparable to moderate to severe hearing loss, and we suspect that users will experience communication difficulties as a result.

Level of Evidence. Prospective study.

Aerosol Dispersion During Mastoidectomy and Custom Mitigation Strategies for Otologic Surgery in the COVID-19 Era

Objective

To investigate small-particle aerosolization from mastoidectomy relevant to potential viral transmission and to test source-control mitigation strategies.

Study Design

Cadaveric simulation.

Setting

Surgical simulation laboratory.

Methods

An optical particle size spectrometer was used to quantify 1- to 10-µm aerosols 30 cm from mastoid cortex drilling. Two barrier drapes were evaluated: OtoTent1, a drape sheet affixed to the microscope; OtoTent2, a custom-structured drape that enclosed the surgical field with specialized ports.

Results

Mastoid drilling without a barrier drape, with or without an aerosol-scavenging second suction, generated large amounts of 1- to 10-µm particulate. Drilling under OtoTent1 generated a high density of particles when compared with baseline environmental levels (P < .001, U = 107). By contrast, when drilling was conducted under OtoTent2, mean particle density remained at baseline. Adding a second suction inside OtoTent1 or OtoTent2 kept particle density at baseline levels. Significant aerosols were released upon removal of OtoTent1 or OtoTent2 despite a 60-second pause before drape removal after drilling (P < .001, U = 0, n = 10, 12; P < .001, U = 2, n = 12, 12, respectively). However, particle density did not increase above baseline when a second suction and a pause before removal were both employed.

Conclusions

Mastoidectomy without a barrier, even when a second suction was added, generated substantial 1- to 10-µm aerosols. During drilling, large amounts of aerosols above baseline levels were detected with OtoTent1 but not OtoTent2. For both drapes, a second suction was an effective mitigation strategy during drilling. Last, the combination of a second suction and a pause before removal prevented aerosol escape during the removal of either drape.

Otopathologic Analysis of Patterns of Postmeningitis Labyrinthitis Ossificans

OBJECTIVE

Labyrinthitis ossificans (LO) may occur following meningitis and, in cases where cochlear implantation is indicated, complicate electrode insertion. LO is critical to identify for successful cochlear implantation, and histopathology is more sensitive than imaging for identification of LO. Herein we utilize otopathologic techniques to study the timing and location of intracochlear tissue formation following meningitic labyrinthitis (ML).

STUDY DESIGN

Retrospective review.

SETTING

Academic institution.

METHODS

Temporal bone specimens with a history of bacterial ML were histologically evaluated. The location and extent of intracochlear tissue formation within the scala tympani (ST) and scala vestibuli (SV) were graded, and spiral ganglion neurons were counted.

RESULTS

Fifty-one temporal bones were identified: 32 with no intracochlear tissue formation, 9 with fibrosis alone, and 10 with LO. Fibrosis was identified as early as 1.5 weeks after ML, while ossification was found only in specimens that survived multiple years after ML. All LO cases showed ossification of the ST at the round window membrane (RWM) with continuous extension throughout the basal turn. Extent of SV ossification correlated with that in the ST but showed frequent isolated distal involvement of the cochlea. Spiral ganglion neuron counts were lower than those in age-matched controls.

CONCLUSION

In this human temporal bone study, we found that postmeningitic LO results in ossification at the RWM with continuous extension into the ST of the basal turn and variable involvement of the SV. Identification of a patent basal turn beyond RWM ossification of the ST should permit full electrode insertion.

LEVEL OF EVIDENCE

Retrospective review.

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.

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.

High-Frequency Conductive Hearing following Total Drum Replacement Tympanoplasty

OBJECTIVES

Conventional reporting of posttympanoplasty hearing outcomes use a pure-tone averaged air-bone gap (ABG) largely representing a low-frequency sound conduction. Few studies report high-frequency conductive hearing outcomes. Herein, we evaluate high-frequency ABG in patients following temporalis fascia total drum replacement.

STUDY DESIGN

Case series with chart review.

SETTING

Tertiary care center.

SUBJECTS AND METHODS

All patients who underwent type 1 tympanoplasty using a lateral graft total drum replacement technique between August 2016 and February 2019 were identified. Patients with pre- and postoperative audiograms were included. Low-frequency ABG was calculated as the mean ABG at 250, 500, and 1000 Hz. High-frequency ABG was calculated at 4 KHz. Pre- and postoperative ABGs were compared.

RESULTS

Twenty-three patients were included, and the mean age at surgery was 44 years (range, 9-68 years). Perforation etiology was from trauma (n = 14) or chronic otitis media (n = 9). Preoperative mean low-frequency ABG was 27.8 ± 12.6 dB and mean high-frequency ABG was 21.5 ± 15.1 dB (P = .044). Postoperatively, the mean low-frequency ABG was significantly reduced by 15.5 ± 13.3 dB (P < .001) while the mean high-frequency ABG insignificantly changed (reduced by 2.6 ± 16.2 dB, P = .450).

CONCLUSION

In a series of patients undergoing temporalis fascia total drum replacement, low-frequency ABG improved; however, high-frequency conductive hearing loss persists. Conventional methods of reporting ABG may not identify persistent high-frequency ABG. These results merit further study across a range of tympanoplasty graft materials and surgical techniques.

Location of Small Intracanalicular Vestibular Schwannomas Based on Magnetic Resonance Imaging

Vestibular schwannomas (VSs) were proposed to arise from the glial-Schwann cell junction within the internal auditory canal (IAC). However, otopathology studies indicate that VS may arise anywhere along the course of the vestibular nerve. Recent studies suggested that the majority of tumors are located centrally within the IAC with an equal distribution near the porus acusticus and the fundus. However, these studies analyzed tumors of all sizes, obscuring their precise origin. Herein, we aim to quantify the position of small intracanalicular tumors (<5 mm), assessing hearing outcomes and growth patterns in relation to tumor position. Of the 38 small intracanalicular tumors analyzed, 61% originated closest to the fundus, 34% at the midpoint, and only 5% closest to the porus acusticus. Tumors were observed with serial magnetic resonance imaging for 3.37 ± 2.65 years (mean ± SD) without intervention. Our findings indicate a lateral predominance of small VS within the IAC, an independence between tumor location and hearing outcomes, and further support the slow natural progression of VS.

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.

Limitations of present models of blast-induced sound power conduction through the external and middle ear

The use of models to predict the effect of blast-like impulses on hearing function is an ongoing topic of investigation relevant to hearing protection and hearing-loss prevention in the modern military. The first steps in the hearing process are the collection of sound power from the environment and its conduction through the external and middle ear into the inner ear. Present efforts to quantify the conduction of high-intensity sound power through the auditory periphery depend heavily on modeling. This paper reviews and elaborates on several existing models of the conduction of high-level sound from the environment into the inner ear and discusses the shortcomings of these models. A case is made that any attempt to more accurately define the workings of the middle ear during high-level sound stimulation needs to be based on additional data, some of which has been recently gathered.

Bilayer Graft for Incisionless In-Office Endoscopic Repair of Tympanic Membrane Perforations: A Pilot Study

Tympanic membrane (TM) perforations may result in significant patient morbidity. While intraoperative myringoplasty or tympanoplasty allow for effective repair, not all patients are candidates for general anesthesia. Herein, we describe a novel graft design and technique for in-office repair of TM perforations in the clinic setting. Two pieces of porcine submucosa material were interdigitated to create a bilayer design with lateral and medial flanges. Topical and injected lidocaine were used for local anesthesia. The perforation was rimmed. Grafts were grasped, and medial flanges were placed through the perforation, with lateral flanges resting on the TM surface. TM repair occurred in 5 awake patients with a mean age of 72 years. There were no complications. All perforations healed, with 1 case requiring a minor in-office revision. Audiometry was performed at 4 weeks. The preoperative air-bone gap (mean 0.25, 0.5, 1, 2, and 4 kHz) was 12.2 ± 4.1 dB, and postoperatively, it was 4.2 ± 2.4 dB (P = .001). Novel design of available graft material may allow for effective in-office TM repair.

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.

Human Otopathology of Cochlear Implant Drill-out Procedures

OBJECTIVE

Human otopathology following drill-out procedures for cochlear implantation (CI) in cases with labyrinthitis ossificans (LO) has not been previously described. This study uses the high sensitivity of histopathology to (1) evaluate surgical drill-out technique with associated intracochlear findings and (2) quantify spiral ganglion neuron populations in a series of patients with LO who underwent CI.

STUDY DESIGN

Retrospective otopathology study.

SETTING

Otopathology laboratory.

SUBJECTS AND METHODS

Temporal bone (TB) specimens from cases with evidence of preoperative intracochlear fibroossification that required a drill-out procedure for CI electrode array insertion were included. All cases were histopathologically evaluated and 3-dimensional reconstructions of the cochleae were performed to interpret drilling paths and electrode trajectories.

RESULTS

Five TB specimens were identified, of which 4 underwent drill-out of the basal turn of the cochlea and 1 underwent a radical cochlear drill-out. In multiple TBs, drilling was imprecise with resultant damage to essential structures. Two TBs showed injury to the modiolus, which was associated with substantially decreased or even absent neuronal populations within these areas. In addition, 2 cases with inadequate drill-out or extensive LO of the basal turn resulted in extracochlear placement of electrode arrays into the vestibule due to persistent obstruction within the basal turn.

CONCLUSION

Otopathology highlights the challenges of drill-out procedures in cases of LO. Imprecise drilling paths, due to distortion of normal cochlear anatomy, risk injury to the modiolus and adjacent neurons as well as extracochlear placement of electrode arrays, both of which may contribute to poorer hearing outcomes.

High Resolution Computed Tomography Atlas of the Porcine Temporal Bone and Skull Base: Anatomical Correlates for Traumatic Brain Injury Research

Brain injuries are a significant cause of morbidity and mortality worldwide. Auditory and vestibular dysfunction may occur following trauma to the temporal bone (TB), including the lateral skull base. The porcine model is a commonly used large animal model for investigating brain injury. Reports detailing porcine TB anatomy based on high resolution computed tomography (HRCT) imaging, however, are limited. Herein, we employ HRCT to evaluate and describe the bony anatomy of the porcine TB and lateral skull base. High-resolution multi-detector and cone beam CT were used to image porcine TBs (n = 16). TBs were analyzed for major anatomical structures and compared to human species. Porcine temporal bone anatomy was readily identifiable by HRCT. Although some variability exists, the ossicular chain, vestibule, cochlea, course of the facial nerve, and skull base are similar to those of humans. Major differences included position of the external auditory canal and mastoid, as well as presence of the petrous carotid canal. Study findings may serve as an atlas to evaluate the porcine middle and inner ear, as well as lateral skull base injuries for future porcine brain injury models or other studies that require CT-based analysis.

Methicillin‐resistant Staphylococcus aureus in acute otitis externa

Objective

Study design

Methods

Results

Conclusion

Level of Evidence

Transcanal endoscopic infracochlear vestibular neurectomy: A pilot cadaveric study

PURPOSE

Effective operative approaches for the treatment of refractory vertigo in Meniere's disease are invasive. Vestibular neurectomy can preserve hearing and has been shown to be effective; however, current approaches require an extensive craniotomy. Transcanal endoscopic approaches to the internal auditory canal (IAC) with cochlear preservation have been recently described and may offer a minimally invasive approach to selectively sectioning the distal vestibular nerves while preserving residual hearing.

MATERIALS AND METHODS

Three cadaveric human heads were imaged using high resolution computed tomography (CT). Anatomic analysis of preoperative CT scans showed adequate diameters (>3 mm) of the infracochlear surgical corridor for access to the IAC. A transcanal endoscopic approach was attempted to section the vestibular nerve. Post-operative CT scans were assessed to define the operative tract, determine cochlear preservation and assess cochlear and facial nerve preservation.

RESULTS

Transcanal endoscopic approach was successfully performed (n = 3) using 3 mm-diameter, 14 cm-length 0°, 30°, and 45° endoscopes and microsurgical drills. In all cases the tympanomeatal flap and ossicular chain remained intact. Internal auditory canalotomy was performed using angled instruments and confirmed in real time via lateral skull base navigation. The vestibular nerves were readily identified and sectioned with preservation of the facial and cochlear nerves. Post-procedure CT showed no violation of the cochlea.

CONCLUSION

A transcanal, infracochlear approach to the IAC may permit a minimally invasive approach to distal vestibular neurectomy in cadavers with appropriate anatomy.

Augmented Reality, Surgical Navigation, and 3D Printing for Transcanal Endoscopic Approach to the Petrous Apex

Otolaryngologists increasingly use patient-specific 3-dimensional (3D)–printed anatomic physical models for preoperative planning. However, few reports describe concomitant use with virtual models. Herein, we aim to (1) use a 3D-printed patient-specific physical model with lateral skull base navigation for preoperative planning, (2) review anatomy virtually via augmented reality (AR), and (3) compare physical and virtual models to intraoperative findings in a challenging case of a symptomatic petrous apex cyst. Computed tomography (CT) imaging was manually segmented to generate 3D models. AR facilitated virtual surgical planning. Navigation was then coupled to 3D-printed anatomy to simulate surgery using an endoscopic approach. Intraoperative findings were comparable to simulation. Virtual and physical models adequately addressed details of endoscopic surgery, including avoidance of critical structures. Complex lateral skull base cases may be optimized by surgical planning via 3D-printed simulation with navigation. Future studies will address whether simulation can improve patient outcomes.

Peripheral Vestibular System Histopathologic Changes following Head Injury without Temporal Bone Fracture

Objective

Vestibular symptoms such as dizziness and vertigo are common after head injury and may be due to trauma to the peripheral vestibular system. The pathophysiology of peripheral vestibular symptoms following head injury without temporal bone (TB) fracture, however, is not well understood. Herein, we investigate the histopathology of the peripheral vestibular system of patients who sustained head injury without a TB fracture.

Study Design

Otopathology study.

Setting

Otopathology laboratory.

Subjects and Methods

TB of subjects with a history of head injury without TB fractures were included and evaluated by light microscopy. Specimens were assessed for qualitative and quantitative characteristics, such as number of Scarpa’s ganglion cells in the superior and inferior vestibular nerves, vestibular hair cell and/or dendrite degeneration in vestibular end organs, presence of vestibular hydrops, and obstruction of the endolymphatic duct.

Results

Five cases (n = 5 TBs) had evidence of vestibular pathology. There was a decrease of 48.6% (range, 40%-59%) in the mean count of Scarpa’s ganglion cells as compared with that of normative historical age-matched controls. Moderate to severe degeneration of the vestibular membranous labyrinth was identified in the posterior, superior, and lateral canals in several cases (50%, n = 4 TBs). The maculae utriculi and sacculi showed mild to severe degeneration in 2 cases. Additional findings include vestibular hydrops (25%, n = 2 TBs) and blockage of the endolymphatic duct (n = 1 TB).

Conclusions

Otopathologic analysis of patients with a history of head injury without TB fracture demonstrated peripheral vestibular otopathology. Future studies are necessary to determine if otopathology findings are directly attributable to head injury.

Otopathologic Changes in the Cochlea following Head Injury without Temporal Bone Fracture

Objective

Hearing loss following temporal bone (TB) fracture may result from direct transection of the middle and inner ear. The pathophysiology of hearing loss due to head injury without TB fracture, however, is not well understood. Few reports describe otopathologic findings. Herein, we investigate the pathologic findings of patients who sustained a head injury without evidence of a TB fracture.

Study Design

Otopathology study.

Setting

Otopathology laboratory.

Subjects

Subjects with a history of head injury without TB fracture.

Methods

The TBs of patients with head injury were evaluated by light microscopy. Inner ear anatomy was evaluated, including counts of spiral ganglion cells (SGCs), hair cells, pillar cells, atrophy of the stria vascularis, and the presence of endolymphatic hydrops. SGC counts were compared with those of historical age-matched controls.

Results

All cases (N = 6 TBs) had evidence of inner ear pathology. Of the 6 cases, 2 (33%) had severe loss of hair cells in all 3 turns of the cochlea, and 4 (67%) cases demonstrated moderate to severe loss at the basal turn of the cochlea. Four cases had scattered atrophy of the stria vascularis, and 3 (50%) had cochlear hydrops. The number of total SGCs was decreased, with an average 53% loss (range, 25%-79%) as compared with controls. The SGC count loss was evenly distributed along Rosenthal’s canal.

Conclusions

Patients with a history of head injury without TB fracture demonstrate inner ear pathology. Further studies are necessary to determine if otopathology findings are directly attributable to trauma.

Otopathologic evaluation of temporalis fascia grafts following successful tympanoplasty in humans

OBJECTIVE

Temporalis fascia is a commonly used graft material in tympanoplasty; however, little is known about how the histological structure of fascia remodels postimplantation. Herein, we aim to quantify the pre- and postoperative microstructure of temporalis fascia and compare histological findings to the native tympanic membrane (TM).

METHODS

Temporal bone specimens having undergone successful subtotal or total drum replacement using temporalis fascia were identified (n = 3). Surgically prepared preimplantation temporalis fascia (PreTF, n = 4) and normal TMs (n = 5) were used as controls. Multiple measurements of thickness of PreTF and of normal and fascia reconstructed TMs at the mesotympanum and hypotympanum were obtained. Collagen fiber patterns of normal and reconstructed TMs were histologically described.

RESULTS

In cases of fascia tympanoplasty, the mean time of surgery to death was 16 years (range 8-28 years). All cases contained an aerated middle ear without residual perforation. There was no significant difference between the thickness of PreTF and fascia of reconstructed TMs (234.9 ± 144.9 μm vs. 162.9 ± 71.9 μm, P = 0.1). The lamina propria and total thicknesses of controls (59.8 ± 39.3 μm and 83.7 ± 42.4 μm, respectively) were thinner than the PreTF and fascia-reconstructed TMs, respectively, in all cases (P ≤ 0.001, P ≤ 0.001). Reconstructed TMs contained a thick, longitudinal fiber structure that was qualitatively similar to PreTF.

CONCLUSION

Based on human temporal bone specimens, temporalis fascia does not significantly remodel, change thickness, or change fibrous structure following successful tympanoplasty. Results have implications for selection and surgical preparation of graft materials in TM reconstruction.

LEVEL OF EVIDENCE

4. Laryngoscope, 128:E351-E358, 2018.

Dorothy Wolff: A Pioneer in Otopathology

Dorothy Wolff, PhD, was an inspirational anatomist, pathologist, auditory physiologist, and surgical innovator. Though little known, she worked throughout the mid-20th century in the midst of a revolution in otologic surgery, influencing well-known otologists such as Julius Lempert, MD, Phillip E. Meltzer, MD, and Richard Bellucci, MD. Wolff's seminal work included pathologic studies of the operated human ear, which provided the anatomic basis for effective modern techniques of surgical hearing rehabilitation. Wolff also developed and refined multiple animal models of otologic pathologies that are still in use today. As an independent, innovative, and ambitious scientist, Dorothy Wolff succeeded in pioneering surgical otopathology to the benefit of us all.

3D-printed tracheoesophageal puncture and prosthesis placement simulator

OBJECTIVES

A tracheoesophageal prosthesis (TEP) allows for speech after total laryngectomy. However, TEP placement is technically challenging, requiring a coordinated series of steps. Surgical simulators improve technical skills and reduce operative time. We hypothesize that a reusable 3-dimensional (3D)-printed TEP simulator will facilitate comprehension and rehearsal prior to actual procedures.

METHODS

The simulator was designed using Fusion360 (Autodesk, San Rafael, CA). Components were 3D-printed in-house using an Ultimaker 2+ (Ultimaker, Netherlands). Squid simulated the common tracheoesophageal wall. A Blom-Singer TEP (InHealth Technologies, Carpinteria, CA) replicated placement. Subjects watched an instructional video and completed pre- and post-simulation surveys.

RESULTS

The simulator comprised 3D-printed parts: the esophageal lumen and superficial stoma. Squid was placed between components. Ten trainees participated. Significant differences existed between junior and senior residents with surveys regarding anatomy knowledge(p<0.05), technical details(p<0.01), and equipment setup(p<0.01). Subjects agreed that simulation felt accurate, and rehearsal raised confidence in future procedures.

CONCLUSIONS

A 3D-printed TEP simulator is feasible for surgical training. Simulation involving multiple steps may accelerate technical skills and improve education.

Diffusion Tensor Imaging of Central Auditory Pathways in Patients with Sensorineural Hearing Loss: A Systematic Review

Objective The radiologic evaluation of patients with hearing loss includes computed tomography and magnetic resonance imaging (MRI) to highlight temporal bone and cochlear nerve anatomy. The central auditory pathways are often not studied for routine clinical evaluation. Diffusion tensor imaging (DTI) is an emerging MRI-based modality that can reveal microstructural changes in white matter. In this systematic review, we summarize the value of DTI in the detection of structural changes of the central auditory pathways in patients with sensorineural hearing loss. Data Sources PubMed, Embase, and Cochrane. Review Methods We used the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement checklist for study design. All studies that included at least 1 sensorineural hearing loss patient with DTI outcome data were included. Results After inclusion and exclusion criteria were met, 20 articles were analyzed. Patients with bilateral hearing loss comprised 60.8% of all subjects. Patients with unilateral or progressive hearing loss and tinnitus made up the remaining studies. The auditory cortex and inferior colliculus (IC) were the most commonly studied regions using DTI, and most cases were found to have changes in diffusion metrics, such as fractional anisotropy, compared to normal hearing controls. Detectable changes in other auditory regions were reported, but there was a higher degree of variability. Conclusion White matter changes based on DTI metrics can be seen in patients with sensorineural hearing loss, but studies are few in number with modest sample sizes. Further standardization of DTI using a prospective study design with larger sample sizes is needed.