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.

Sex and Race Representation in Temporal Bone Histopathology Studies in the United States: A Systematic Review

OBJECTIVES

The author's objective was to evaluate sex and race representation in temporal bone histopathology studies.

DESIGN

PubMed, Embase, Cochrane, Web of Science, and Scopus were searched for studies written in English examining temporal bone histopathology specimens from U.S.-based institutions from January 1, 1947, to September 1, 2021. Two authors then performed "snowballing" by reviewing references from the initial search and included the studies that fulfilled the inclusion criteria. For each study, the following information was collected: publication details, study design, funding, institution from where temporal bone specimens were procured, number of study specimens, and donor demographical information.

RESULTS

The authors found that out of 300 studies, 166 (55%) report sex while only 15 (5%) reported race information. Over the past 70 years, the ratio of studies reporting sex to those that do not has increased from 1.00 to 2.19 and the number of female temporal bone histopathology subjects relative to male has increased from 0.67 to 0.75. Over 90% of studies that do report this information feature participant racial compositions that do not reflect the diversity of the U.S. population.

CONCLUSIONS

Studies of temporal bone histopathology often do not report participant sex or race. The reporting of participant sex and the inclusion of specimens from female donors have both increased over time. However, temporal bone histopathology study cohorts are not representative of the racial diversity of the U.S. population. The otolaryngology community must strive to build temporal bone histopathology libraries that are representative of the diverse U.S. population.

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.

Otopathologic Abnormalities in CHARGE Syndrome

OBJECTIVE

To perform an otopathologic analysis of temporal bones (TBs) with CHARGE syndrome.

STUDY DESIGN

Otopathologic study of human TB specimens.

SETTING

Otopathology laboratories.

METHODS

From the otopathology laboratories at the University of Minnesota and Massachusetts Eye and Ear Infirmary, we selected TBs from donors with CHARGE syndrome. These TBs were serially sectioned at a thickness of 20 µm, and every 10th section was stained with hematoxylin and eosin. We performed otopathologic analyses of the external ear, middle ear (middle ear cleft, mucosal lining, ossicles, mastoid, and facial nerve), and inner ear (cochlea, vestibule, internal auditory canal, and cochlear and vestibular nerves). The gathered data were statistically analyzed.

RESULTS

Our study included 12 TBs from 6 donors. We found a high prevalence of abnormalities affecting the ears. The most frequent findings were stapes malformation (100%), aberrant course of the facial nerve (100%) with narrow facial recess (50%), sclerotic and hypodeveloped mastoids (50%), cochlear (100%) and vestibular (83.3%) hypoplasia with aplasia of the semicircular canals, hypoplasia and aplasia of the cochlear (66.6%) and vestibular (91.6%) nerves, and narrowing of the bony canal of the cochlear nerve (66.6%). The number of spiral ganglion and Scarpa's ganglion neurons were decreased in all specimens (versus normative data).

CONCLUSIONS

In our study, CHARGE syndrome was associated with multiple TB abnormalities that may severely affect audiovestibular function and rehabilitation.

The Pathology of the Vestibular System in CANVAS

OBJECTIVE

To describe the site of lesion responsible for the severe, bilateral, symmetrical, selective loss of vestibular function in Cerebellar Ataxia with Neuronopathy and Vestibular Areflexia Syndrome (CANVAS), an adult-onset recessively-inherited ataxia, characterized by progressive imbalance due to a combination of cerebellar, somatosensory, and selective vestibular impairment with normal hearing.

METHODS

Histologic examination of five temporal bones and the brainstems from four CANVAS patients and the brainstem only from one more, each diagnosed and followed from diagnosis to death by one of the clinician authors.

RESULTS

All five temporal bones showed severe loss of vestibular ganglion cells (cell counts 3-16% of normal), and atrophy of the vestibular nerves, whereas vestibular receptor hair cells and the vestibular nuclei were preserved. In contrast, auditory receptor hair cells, the auditory ganglia (cell counts 51-100% of normal), and the auditory nerves were relatively preserved. In addition, the cranial sensory ganglia (geniculate and trigeminal), present in two temporal bones, also showed severe degeneration.

CONCLUSIONS

In CANVAS there is a severe cranial sensory ganglionopathy neuronopathy (ganglionopathy) involving the vestibular, facial, and trigeminal ganglia but sparing the auditory ganglia. These observations, when coupled with the known spinal dorsal root ganglionopathy in CANVAS, indicate a shared pathogenesis of its somatosensory and cranial nerve manifestations. This is the first published account of both the otopathology and neuropathology of CANVAS, a disease that involves the central as well as the peripheral nervous system.

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

LEVEL OF EVIDENCE

Retrospective study.

Invasion Patterns of External Auditory Canal Squamous Cell Carcinoma: A Histopathology Study

OBJECTIVES/HYPOTHESIS

To describe the histopathology of the invasion patterns of advanced-stage external auditory canal (EAC) squamous cell carcinoma (SCC). Study Design Retrospective cohort study.

METHODS

Retrospective analysis of medical records of patients diagnosed with EAC SCC available at the Massachusetts Eye and Ear temporal bone (TB) collection. TBs underwent processing for histologic examination. Hematoxylin and eosin-stained slides were examined. Histologic findings were compared to premortem clinical data.

RESULTS

Nine TBs were identified. Male:female ratio was 6:3. The average age of diagnosis and duration of survival was 64 (46-80 years) and 2.3 years (1-50 months), respectively. All presented with T4 disease, most commonly due to petrous apex (PA) invasion and facial nerve (FN) weakness. The mastoid air cells system served as a tumor conduit to the tegmen mastoideum and overlying dura in four patients, posterior fossa dura in one patient, vertical segment of FN in four patients, and middle ear (ME) and lateral semicircular canal in five patients. The tumor did not penetrate the tympanic membrane, oval window membrane (fenestra vestibule), or round window (RW) membrane. Supra- and infralabyrinthine pneumatization patterns allowed direct routes to the PA. Translabyrinthine PA invasion was seen in two patients. The most common locus of otic capsule invasion was the cochlea. One patient had FN paralysis due to compression rather than invasion.

CONCLUSIONS

SCC does not tend to extend from the ME to the inner ear through the RW and vestibule-stapedial ligament. Tumors tend to spread along the preexisting TB air-tract routes. Well-aerated TB, may facilitate extension to the PA.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E590-E597, 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.

Cochlear turns measurements in patients with meningitis: A histopathological study

OBJECTIVE

To demonstrate the cochlear turns area changes among patients with a history of meningitis, through otopatologic study.

METHODS

We performed an analysis of the area of the bony cochlear turns and the cochlear lumen of the horizontal sections containing the modiolus and the area of the basal turn at the level of round window, in temporal bones obtained from patients with a history of meningitis and compared to a nondiseased control group.

RESULTS

The mean area of the bony walls and the lumen of all cochlear turns are reduced within the meningitis group. Patients who presented a time from the diagnosis of meningitis to death longer than 30 days had a significant reduction in the cochlear turns area, as compared to the control group.

CONCLUSION

Future studies may further correlate audiologic outcomes, cochlear volume, and cochlear area among patients with meningitis.

Histological characteristics of intra-temporal facial nerve paralysis in temporal bone malignancies

OBJECTIVE

To describe the histopathologic findings and clinical presentation of intra-temporal facial nerve invasion in primary and metastatic malignancies of the human temporal bone (TB).

MATERIALS AND METHODS

Retrospective analysis of all medical records of patients diagnosed with peripheral facial nerve palsy (PFnP) of a malignant origin was performed. Temporal bones underwent standard processing for histologic examination. Hematoxylin and eosin (H&E)-stained slides were examined by light microscopy. The histologic findings were compared to premortem clinical data.

RESULTS

Eighteen TBs were identified in 16 patients. The male to female ratio was 9:7. The median (range) age of death was 56.5 years (27 months to 75 years). The median time interval from facial nerve injury to death was 5.5 months. There were 11 carcinomas and seven sarcomas identified. Primary TB malignancies were identified in seven TBs (39%), and the rest (11 TBs, 61%) were of metastatic origin. Complete facial nerve paralysis (House-Brackmann [HB] grade VI), was the most common clinical presentation affecting nine patients (10 TBs, 56%). Neural involvement was multifocal in nature (16 of 18 TBs, 89%). The most commonly involved cranial nerve (CN) VII segment was the meatal segment (13 TBs, 72%), followed by the labyrinthine, tympanic, and vertical segments (nine, eight, and six TBs, respectively).

CONCLUSION

PFnP can be the result of local, regional, or distant malignancy, and is associated with poor survival. The facial nerve can serve as a route of tumor progression intracranially. Whereas every segment of CNV II can be violated by tumors, not all PFnP are related to direct tumor invasion.

LEVEL OF EVIDENCE

4 Laryngoscope, 130:E358-E367, 2020.

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.

Otopathology in CHARGE syndrome

Postmortem temporal bone computed tomography (CT) and histopathologic findings in an infant with CHARGE syndrome revealed bilateral cochleovestibular hypoplasia, including cochlear pathology relevant to cochlear implant candidacy. Both ears had absence of the superior semicircular canals (SCCs), severely hypoplastic posterior SCCs, and hypoplastic (right ear) or absent (left ear) lateral SCCs seen on CT and histopathology. Histopathology further revealed the absence of all SCC ampullae except the right lateral SCC ampulla and atrophic vestibular neuroepithelium in the saccule and utricle bilaterally. The right cochlea consisted of a basal turn with patent round window, and malformed middle turn (type IV cochlear hypoplasia), with a small internal auditory canal (IAC) but near normal cochlear nerve aperture (fossette). Quantification of spiral ganglion neurons (SGNs) on histologic sections revealed a reduced SGN population (35% of normal for age), but this ear would still have likely achieved benefit from a cochlear implant based on this population. The left cochlea consisted of only a basal turn with patent round window (type III cochlear hypoplasia) with a small IAC and very small cochlear nerve aperture. Notably, histology revealed that there were no SGNs in the cochlea, and therefore, this ear would not have been a good candidate for cochlear implantation.

Level of evidence: IV.

Temporal bone histopathology in MELAS syndrome

OBJECTIVES

Describe the histopathology of the temporal bones in MELAS (myopathy, encephalopathy, lactic acidosis, and stroke-like episodes) syndrome. The syndrome results from a known point mutation in mitochondrial DNA.

METHODS

Histopathology analysis of a pair of temporal bones from the oldest surviving MELAS syndrome temporal bone donor. Histopathologic findings were correlated with known premortem clinical data.

RESULTS

The inner ears showed severe but incomplete atrophy of the stria vascularis for the length of the cochleae. In contrast, the organ of Corti and inner hair cells appeared intact with some loss of outer hair cells. Other than moderate loss at the basal turn, spiral ganglion cells numbers were normal. The vestibular neuroepithelium was mostly normal with the exception of moderate degeneration of the macula sacculi and partial collapse of the saccular wall on the right. The cerebral cortex had infarct-like lesions with adjacent gliosis.

CONCLUSION

This is an analysis of the oldest patient with MELAS syndrome to date, an addition to only two previously published patients. It supports the notion that hearing loss is a result of dysfunction of the stria vascularis and not loss of hair cells or neurons. Patterns of vestibular pathology are in agreement to in-vivo measurements. These findings support auditory rehabilitation with cochlear implants and may be relevant to hearing loss due to other mitochondrial mutations.

LEVEL OF EVIDENCE

4.

Otopathology Findings in Otosclerosis With Lateral Semicircular Canal Fenestration

A study of clinical records and temporal bone histopathology from a woman with bilateral otosclerosis who was treated with lateral semicircular canal fenestration procedures as well as stapedectomy.

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.

Temporal Bone Histopathology of X-linked Inherited Alport Syndrome

OBJECTIVE

To describe the histopathologic findings within the human cochlea in X-linked Alport syndrome.

STUDY DESIGN

Histopathologic analysis of cellular elements within the human cochlea by light microscopy.

MATERIALS AND METHODS

A right and a left cochleae of a man with genetically confirmed X-linked Alport syndrome was studied post-mortem. The temporal bones underwent standard processing for histologic examination. The slides were examined by light microscopy. Graphic reconstruction of the cochlea was performed to quantify hair cells, pathologic changes of the stria vascularis, and loss of cochlear neuronal cells.

RESULTS

There was severe loss of inner hair cells and all three rows of outer hair cells in the apical two turns of the cochlea. The stria vascularis and spiral ligament showed areas of marked loss which became more prominent from base to apex in each ear. The spiral ganglion cell count in the Rosenthal's canal exhibited loss of 20% to 45% compared to matched historical controls. There was a zone of separation between the organ of Corti and the basilar membrane extending along the basal surface of Deiters cells, Hensen cells, Claudius cells and external sulcus cells. The tunnel of Corti and the space of Nuel were filled with cellular elements along the cochlea.

CONCLUSION

The histopathologic findings of cochlear involvement in Alport's syndrome are basement membrane separation from the cells of the organ of Corti, outer and inner hair cell loss, and cellular infilling of the tunnel and extracellular spaces of the organ of Corti. These observations contribute to our understanding of the mechanism of sensorineural hearing loss in these patients.

LEVEL OF EVIDENCE

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.

Middle Ear Histopathology Following Magnetic Delivery to the Cochlea of Prednisolone-loaded Iron Oxide Nanoparticles in Rats

Delivery of therapy to the cochlea is a challenge and limits the efficacy of therapies meant to treat hearing loss, reverse tinnitus, and protect hearing from chemotherapy regimens. Magnetic injection is a technique that uses magnetic fields to inject nanoparticles from the middle ear into the cochlea, where they can then elute therapy to treat hearing disorders. To evaluate the safety of this treatment in the middle ear, 30 rats were subdivided into 6 groups and treated by single or multiple intratympanic injections of saline, prednisolone, nanoparticles, or nanoparticles loaded with prednisolone. A specially designed magnet array was used to magnetically inject the particles from the middle ear to the cochlea. Treatment began at study day 0, and animals were euthanized on study day 2, 30, or 90. Temporal bones were collected and prepared for histopathological examination. Intratympanic administration of magnetic nanoparticles and/or prednisolone resulted in minimal to mild inflammatory changes in all treated groups. The incidence and severity of the inflammatory changes observed appeared slightly increased in animals administered nanoparticles, with or without prednisolone, when compared to animals administered prednisolone alone. At study day 90, there was partial reversibility of the findings noted at study day 2 and 30. Repeat administration did not appear to cause greater inflammatory changes.