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.

Otopathologic and Computed Tomography Correlation of Internal Auditory Canal Diverticula in Otosclerosis

INTRODUCTION

Internal auditory canal (IAC) diverticula, also known as IAC cavitary lesions or anterior cupping of the IAC, observed in otopathologic specimens and high-resolution computed tomography (CT) scans of the temporal bone are thought to be related to otosclerosis. Herein, we examined the usefulness of CT scans in identifying diverticula and determined whether IAC diverticula are associated with otosclerosis on otopathology.

METHODS

One hundred five consecutive specimens were identified from the National Temporal Bone Hearing and Balance Pathology Resource Registry. Inclusion criteria included the availability of histologic slides and postmortem specimen CT scans. Exclusion criteria included cases with severe postmortem changes or lesions causing bony destruction of the IAC.

RESULTS

Ninety-seven specimens met criteria for study. Of these, 42% of the specimens were from male patients, and the average age of death was 77 years (SD = 18 yr). IAC diverticula were found in 48 specimens, of which 46% were identified in the CT scans. The mean area of the IAC diverticula was 0.34 mm 2 . The sensitivity and specificity of detecting IAC diverticula based on CT were 77% and 63%, respectively. Overall, 27% of specimens had otosclerosis. Histologic IAC diverticula were more common in specimens with otosclerosis than those without (37.5% versus 16%; p = 0.019). Cases with otosclerosis had a greater mean histologic diverticula area compared with nonotosclerosis cases (0.69 mm 2 versus 0.14 mm 2 ; p = 0.001).

CONCLUSION

IAC diverticula are commonly found in otopathologic specimens with varied etiologies, but larger diverticula are more likely to be associated with otosclerosis. The sensitivity and specificity of CT scans to detect IAC diverticula are limited.

"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.

Association of Pediatric Hearing Quality and Sports Participation: A Population-Based Study

Sports-related injuries, such as concussion, during childhood may result in considerable morbidity, including a range of negative developmental consequences. Auditory dysfunction is generally recognized to be a possible sequela of sports-related concussion; however, few epidemiologic studies have quantified the association between hearing quality and sports-related activity in the pediatric population. The National Health and Nutrition Examination Survey for the 2015-2016 cycle was utilized to determine the association of sports activities and hearing quality. Subjective abnormal hearing quality was more frequent among children who played football than those that did not (36.5% vs 26.8%; odds ratio, 1.56 [95% CI, 1.23-2.00]; P = .001). Other sports, such as basketball and soccer, did not have this association with hearing quality (P = .496 and P = .852, respectively). Our findings suggest a notable association between practice of a potentially high concussion sport and hearing quality. Children practicing football are 1.56 times more likely to report abnormal hearing quality.Level of Evidence: 4.

Posterior petrous face meningiomas presenting with Ménière's-like syndrome: a case series and review of the literature

OBJECTIVE

Ménière's disease is an inner ear disorder classically characterized by fluctuating hearing loss, tinnitus, and aural fullness accompanied by episodic vertigo. While the pathogenesis of Ménière's remains under debate, histopathological analyses implicate endolymphatic sac dysfunction with inner ear fluid homeostatic dysregulation. Little is known about whether external impingement of the endolymphatic sac by tumors may present with Ménière's-like symptoms. The authors present a case series of 7 patients with posterior fossa meningiomas that involved the endolymphatic sac and new onset of Ménière's-like symptoms and review the literature on this rare clinical entity.

METHODS

A retrospective review of patients undergoing resection of a posterior petrous meningioma was performed at the authors' institution. Inclusion criteria were age older than 18 years; patients presenting with Ménière's-like symptoms, including episodic vertigo, aural fullness, tinnitus, and/or hearing loss; and tumor location overlying the endolymphatic sac.

RESULTS

There were 7 cases of posterior petrous face meningiomas involving the vestibular aperture presenting with Ménière's-like symptoms. Imaging and intraoperative examination confirmed no cranial nerve VIII compression or labyrinthine artery involvement accounting for audiovestibular symptoms. Of the 7 patients in the series, 6 experienced significant improvement or resolution of their vertigo, and all 7 had improvement or resolution of their tinnitus after resection. Of the 5 patients who had preoperative hearing loss, 2 experienced improvement or resolution of their ipsilateral preoperative hearing deficit, whereas the other 3 had unchanged hearing loss compared to preoperative evaluation.

CONCLUSIONS

Petrous face meningiomas overlying the endolymphatic sac can present with a Ménière's syndrome. Early recognition and microsurgical excision of these tumors is critical for resolution of most symptoms and stabilization of hearing loss.

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.

Association of Pediatric Hearing Loss and Head Injury in a Population-Based Study

Traumatic brain injury (TBI) is the leading cause of acquired long-term disability during childhood, and it may result in wide range of negative developmental consequences. Auditory dysfunction is generally recognized to be a possible sequela of pediatric TBI. Unfortunately, few contemporary studies have quantified the association between head injury and hearing loss in the pediatric population. The National Survey of Children's Health (NSCH) for the combined years 2017-2018 was used to determine the association of hearing loss with TBI. Deafness or problems with hearing were more commonly reported in children with a history or current brain injury/concussion compared to those without any such history (3.2% [70,000] and 1.2% [830,000] children, respectively; odds ratio, 2.67; P < .001). Findings suggest a notable association between TBI and hearing loss. Children with a history of TBI are 2.67 times more likely to have concurrent hearing complaints.Level of Evidence: IV.

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.

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.

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.

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.

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.

Systematic review of hearing loss after traumatic brain injury without associated temporal bone fracture

OBJECTIVE

While hearing loss following temporal bone fracture is a well-described phenomenon, few data exist on auditory dysfunction in patients with traumatic brain injury (TBI) without temporal bone fracture. Herein, we aim to systematically review hearing loss after TBI without bony fracture and describe its etiologies.

DATA SOURCES

Pubmed, Embase, Cochrane databases.

REVIEW METHODS

A systematic review of the literature from 1966 to January 2017 was performed using Preferred Reporting Items for Systematic Reviews and Meta-analyses recommendations. Data were obtained from studies that investigated hearing loss in TBI without skull fracture according to an a priori protocol with inclusion and exclusion criteria. Variables included type and severity of hearing loss, as well as pathophysiology of hearing loss.

RESULTS

There were 13 studies with 773 patients that met study criteria. Overall, there was one prospective cohort study, four retrospective cohort studies, two case-control studies, and six case reports. The studies with the highest level of evidence report a change in hearing of at least 10-15 dB across a range of frequencies in as many as 58% percent of TBI patients without bony fracture, which was transient or chronic. The mechanism/severity of injury may impact the rate of hearing loss.

CONCLUSIONS

Hearing loss after TBI in the absence of bony injury appears to be a clinically significant but poorly characterized phenomenon.

Otogenic brain abscesses: A systematic review

Objective

Otogenic brain abscesses are one of the most significant life-threatening complications of otologic infections. Given their low prevalence, otogenic brain abscesses require a high index of suspicion for diagnosis. In this systematic review, we aim to provide an analysis of otogenic brain abscesses and describe common clinical signs and symptoms, bacteriology, location, treatment options, morbidity, and mortality.

Data Sources

PubMed, Cochrane CENTRAL database, Google Scholar, and Scopus.

Methods

A systematic review of literature was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses recommendations. Variables assessed included clinical signs and symptoms, bacteriology, location, treatment, morbidity, and mortality.

Results

Twenty-nine studies met inclusion and exclusion criteria, corresponding to a total of 1307 otogenic abscess cases for review. Fifty-five percent of abscesses were found in the temporal lobe and 28% in the cerebellum. Most patients (88.3%) had a history of suppurative chronic otitis media. The most common symptoms were headache, altered mental status, papilledema, and meningeal irritation. Fever, nausea, and vomiting affected about 40% of patients. The most commonly cultured bacterial species was Proteus mirabilis. In addition to antibiotics, most otogenic brain abscesses were treated by burr hole aspiration. Average mortality following advent of computed tomography was 8.11%.

Conclusion

Although rare, otogenic brain abscesses may occur as a complication of suppurative otitis media and require a high index of suspicion. Appropriate imaging studies and multidisciplinary expertise are crucial in the diagnosis and management.

Level of Evidence

4.