The surgical challenge of carotid artery and Fallopian canal dehiscence in chronic ear disease: a pitfall for endoscopic approach

OBJECTIVE

Endoscopic procedures are becoming common in middle ear surgery. Inflammation due to chronic ear disease can cause bony erosion of the carotid artery and Fallopian canals, making them more vulnerable during surgery. The objective of this study was to determine whether or not chronic ear disease increases dehiscence of the carotid artery and Fallopian canals.

DESIGN

Comparative human temporal bone study.

SETTING

Otopathology laboratory.

PARTICIPANTS

We selected 78 temporal bones from 55 deceased donors with chronic otitis media or cholesteatoma and then compared those two groups with a control group of 27 temporal bones from 19 deceased donors with no middle ear disease.

MAIN OUTCOME MEASURES

We analysed the middle ear, carotid artery canal and Fallopian canal, looking for signs of dehiscence of its bony coverage, using light microscopy.

RESULTS

We found an increased incidence in dehiscence of the carotid artery and Fallopian canals in temporal bones with chronic middle ear disease. The size of the carotid artery canal dehiscence was larger in the middle ear-diseased groups, and its bony coverage, when present, was also thinner compared to the control group. Dehiscence of the carotid artery canal was more frequently located closer to the promontory. The incidence of Fallopian canal dehiscence was significantly higher in temporal bones from donors older than 18 years with chronic middle ear disease.

CONCLUSION

The increased incidence of the carotid artery and Fallopian canal dehiscence in temporal bones with chronic middle ear disease elevates the risk of adverse events during middle ear surgery.

Pattern changes of mucin gene expression with pneumococcal otitis media

OBJECTIVE

mucins, known to be important components of the mucociliary transport system in the middle ear and Eustachian tube, are subject to changes under inflammatory conditions. Which mucin genes are up-regulated or activated during an inflammatory reaction of the middle ear and Eustachian tube, however, is poorly understood. The purpose of this study was to characterize mucin gene expression in middle ears and Eustachian tubes with pneumococcal ear infection.

METHODS

sixteen rats received intrabullar inoculation of Streptococcus pneumoniae type 6A at 2.5x10(6) colony forming units (CFU). Four animals were sacrificed on days 1, 3, 7, and 14, respectively. The profile of mucin gene expression in the middle ear and Eustachian tube was examined by reverse transcription polymerase chain reaction (RT-PCR) at the above time points. Sixteen rats that received intrabullar inoculation of phosphate-buffered saline (PBS) served as controls.

RESULTS

the Muc2 mucin gene was expressed in middle ear mucosa of the control rats. Following pneumococcal inoculation, Muc1-Muc5 mucin genes were expressed in the middle ear mucosa in a time-dependent manner. In the Eustachian tube, the Muc2, Muc4 and Muc5 mucin genes were expressed in both control and pneumococcal inoculation groups.

CONCLUSION

Muc1, Muc3, Muc4, and Muc5 mucin genes were activated in the middle ear mucosa by pneumococci, which may contribute to hyper-production of mucin in acute pneumococcal otitis media.

Stapes mobilization in otosclerosis

We performed a retrospective chart study (including surgeon's notes and audiometric results) and an analysis of the archival temporal bones from a patient who had undergone surgery for stapes mobilization in both ears. The stapes footplate was submerged into the vestibule on the right (as a complication of surgery) and absent on the left. One interesting finding was that the patient's hearing had improved on the right despite the presence of the depressed footplate and that the air-bone gap had widened on the left despite the absence of complications on that side.

Characterization of mucins in human middle ear and Eustachian tube

Mucins are important glycoproteins in the mucociliary transport system of the middle ear and Eustachian tube. Little is known about mucin expression within this system under physiological and pathological conditions. This study demonstrated the expression of MUC5B, MUC5AC, MUC4, and MUC1 in the human Eustachian tube, whereas only MUC5B mucin expression was demonstrated in noninflamed middle ears. MUC5B and MUC4 mucin genes were upregulated 4.2- and 6-fold, respectively, in middle ears with chronic otitis media (COM) or mucoid otitis media (MOM). This upregulation of mucin genes was accompanied by an increase of MUC5B- and MUC4-producing cells in the middle ear mucosa. Electron microscopy of the secretions from COM and MOM showed the presence of chainlike polymeric mucin. These data indicate that the epithelium of the middle ear and Eustachian tube expresses distinct mucin profiles and that MUC5B and MUC4 mucins are highly produced and secreted in the diseased middle ear. These mucins may form thick mucous effusion in the middle ear cavity and compromise the function of the middle ear.

Tympanic membrane and middle ear pathologic correlates in mucoid otitis media

OBJECTIVE

The goal of this study was to correlate tympanic membrane (TM) and middle ear (ME) pathologies in mucoid otitis media (MOM).

METHODS AND MATERIAL

Forty ears with MOM and 56 control ears were retrospectively evaluated for TM and ME pathologies. Comparisons of TM thicknesses in MOM versus control ears were correlated with the Student t test; chi(2) analysis was used to correlate pathologic findings of the TM and ME.

RESULTS

Thicknesses in all quadrants except the umbo were increased in MOM because of infiltration of inflammatory cells and fibrosis. The most common ME pathologies were granulation tissue and fibrosis. Significant correlations included (1) TM retraction and ME granulation tissue and fibrosis and (2) pars flaccida, posterosuperior, and anteroinferior thickness and ME granulation tissue and fibrosis.

CONCLUSION

TM changes are likely to occur in patients with otitis media with effusion (MOM), and their presence is a strong indication of underlying ME pathology.

Petrous high jugular bulb: a histological study

PURPOSE

A high jugular bulb (JB) is thought to affect structures of the inner ear and possibly cause symptoms there, but clear histological findings of an anatomical relationship between a high JB and the inner ear have not yet been described.

MATERIALS AND METHODS

We surveyed horizontal sections of 1,591 temporal bones from the collection of the Otopathology Laboratory at the University of Minnesota in Minneapolis, Minnesota, defining a high JB as a JB extending above the inferior margin of the basal cochlear turn.

RESULTS

In 65 specimens (16%), we found a high JB with its vascular wall obviously thinner than that of a low JB. Bony resorption was occasionally observed around high JBs. Sixteen specimens showed a bony deshiscence between the JB and the endolymphatic sac. Clinical charts showed no obvious symptoms associated with a high JB.

CONCLUSIONS

Our findings suggest that the JB may have potential to expand upward postnatally. Although our study confirmed occasional bony dehiscence between the JB and the endolymphatic sac, JBs with this involvement may have only a minor effect on function in the inner ear.

Identification of MUC5B mucin gene in human middle ear with chronic otitis media

OBJECTIVES

To identify the mucin gene and its expressing cells in the middle ear mucosa with chronic otitis media (COM), and to study the correlation between infiltration of inflammatory cells in the submucosa and expression of the mucin gene in the mucosal epithelium with COM.

STUDY DESIGN

Middle ear mucosal specimens removed from the inferior promontory area of 19 patients undergoing middle ear surgery for COM were studied.

METHODS

Sections were stained with H&E, Alcian blue-periodic acid Schiff (AB-PAS), polyclonal MUC5B antibody, and specific MUC5B riboprobe for histological, histochemical, immunohistochemical, and mucin mRNA analyses.

RESULTS

H&E staining revealed pseudostratified epithelia in 18 of the middle ear specimens with COM and cuboidal secretory epithelia in one. AB-PAS staining of epithelia revealed abundant secretory cells and their products (glycoconjugates). In situ hybridization and immunohistochemistry studies demonstrated that the secretory cells of the middle ear mucosa with COM expressed MUC5B mucin mRNA and its product MUC5B mucin.

CONCLUSIONS

The MUC5B mucin gene and its product were identified in the middle ear secretory cells of patients with COM. Its expression was extensive in pseudostratified mucosal epithelia and related to infiltration of inflammatory cells in the submucosa of the middle ear cleft with COM, suggestive that inflammatory cell products are involved in the production of MUC5B.

Facial neuroma in the internal auditory canal

Authors presented two cases of facial neuromas in the internal auditory canal, one without facial palsy and the other with facial palsy. In both cases neuromas were occult and undiagnosed. Although in the first case neuroma was greater than the other, facial palsy was not developed. The mechanism of the facial palsy due to neuromas could not be clearly clarified.

Improved RNA analysis for immediate autopsy of temporal bone soft tissues

RNA analysis is essential for understanding biological activities of a cell or tissue. Unfortunately, retrieval of RNA from existing archives of human temporal bones has proven extremely difficult due to degradation of RNA molecules. The major factors that contribute to degradation of RNA in specimens from autopsied temporal bones are tissue autolysis due to time elapsed before autopsy, and technical problems in processing the bones after harvest. We therefore focused on improving the survival of RNA in human temporal bones by shortening the time to autopsy and through modification of the processing technique by removing targeted tissues directly from the temporal bones and by avoiding time-consuming decalcification and celloidin-embedding. Eight temporal bones collected at immediate autopsies were used in this study. Representative mRNAs, ranging from high (MUC5B, physically unstable) to low (beta-actin, physically stable) molecular weights, and from abundant (MUC5B) to non-abundant (MUC1) RNA, were studied by in situ hybridization, Northern blot technique, or both. Using this modified protocol in autopsies performed up to 6 h after death, the existence of mRNAs was demonstrated in all bones studied. This improved method demonstrates the feasibility of the use of autopsied temporal bone tissues for RNA analysis.

Metastases to temporal bones from primary nonsystemic malignant neoplasms

OBJECTIVES

To compare histopathological and clinical findings of metastasis to the temporal bone with previous reports and to determine the prevalence of these metastases in patients with nonsystemic cancer.

STUDY DESIGN

Retrospective.

METHODS

Autopsy records of 864 patients were screened to select those with primary nondisseminated malignant neoplasms. These were evaluated histopathologically for metastasis to and site of involvement within the temporal bone, and histological characteristics of the tumor. Clinical records and autopsy reports were reviewed for demographic data, clinical course, otologic and vestibular manifestations, site of primary and its histological features, extent of metastasis, and mode of spread.

RESULTS

Of 212 patients with primary nondisseminated malignant neoplasms, 47 had metastases to the temporal bone (76 temporal bones). Twenty different primary tumors had metastasized, most commonly breast cancer. Hearing loss was the most common otologic symptom (seen in 19 patients [40%]), while 17 (36%) had no otologic or vestibular symptoms. Temporal bone involvement was bilateral in 29 patients (62%). Most metastases to the temporal bone demonstrated hematogenous spread in 58 temporal bones (76.7%), and petrous apex was the most common site of metastases in 63 temporal bones (82.9%). Temporal bone metastases were not observed in cases where the primary tumor was adequately treated.

CONCLUSIONS

In the largest series to date, we found temporal bone metastases more frequently than previously reported. Absence of temporal bone involvement in cases in which the primary tumor was adequately treated stresses the need for early management of cancer. Metastatic disease must be considered as a cause of hearing loss in patients with a history of malignant neoplasm.

Histopathologic features of the temporal bone in patients with cystic fibrosis

OBJECTIVES

To investigate the lower than expected incidence of otitis media in patients with cystic fibrosis (CF) through histopathologic evaluation of temporal bones and to document pathologic findings in the inner ears of patients with CF who received long-term administration of antibacterial and diuretic agents.

DESIGN

Clinical records of patients who died of CF were reviewed. Their temporal bones were sectioned, stained with hematoxylin-eosin, and examined histologically. Additional sections were stained with Alcian blue and periodic acid-Schiff for comparison of goblet cell densities from middle ears and auditory tubes of patients with CF with those of control temporal bones. Results were analyzed using the t test.

SUBJECTS

Twenty-one temporal bones from 11 patients with CF and 13 bones from 8 age-matched patients without CF were selected.

RESULTS

All temporal bones with CF had well-pneumatized mastoids. Temporal bones from 2 patients (3 ears) revealed histological findings of chronic otitis media with effusion. There was a statistically significant reduction in the density of goblet cells in the medial (P = .002) and lateral (P = .05) walls in patients with CF who had no otitis media histologically compared with control temporal bones. Two patients with CF who had otitis media had increased densities of goblet cells. Inner ear damage, due to ototoxic drugs, was seen in most of the temporal bones from patients with CF.

CONCLUSION

Low densities of goblet cells in temporal bones with CF may contribute reduced amounts of viscous mucus, which can lead to a low incidence of otitis media.

Congenital malformations of middle and inner ears of parabiotic twins

We describe herein the congenital malformations of the middle and inner ears in temporal bones of parabiotic, monozygotic twins. Temporal bones were removed from twin B, who had no fetal cardiac activity and was born dead at 23-4/7 weeks, and twin A, the donor or "pump" twin in intrauterine life, who died shortly after birth at 20-6/7 weeks. The temporal bones were processed routinely in celoidin, stained with hematoxylin and eosin, and examined by light microscopy. We found that twin B had Mondini's dysplasia with associated deformities of the middle ear and in general showed more developmental anomalies than twin A, and we conclude that Mondini's dysplasia with anomalies of the middle ear may occur in the parabiotic twin syndrome, and the abnormalities may be explainable as the result of vascular disturbance, which also causes other lesions in these unusual cases.

Residual mesenchyme persisting into adulthood

PURPOSE

(1) To detect the presence of residual mesenchyme in temporal bones of adults and children above 5 years of age; (2) to evaluate its regression with increasing age, and; (3) to detect pathologic conditions associated with the presence of unresolved mesenchyme.

MATERIALS AND METHODS

We examined 1,404 human temporal bones of donors from 5 to 94 years of age for histopathologic evidence of mesenchyme. The presence of stellate (star-shaped) cells with interdigitating processes and large nuclei embedded in a structureless ground substance was labeled as "pure mesenchyme." Temporal bones showing these features and focal areas of fibrosis, fibroblasts, and capillaries were classified as showing "transitional mesenchyme." Selected sections were stained with Gomori's trichrome. Pathological features indicating otitis media and congenital anomalies of the ear were also documented. Case histories were reviewed, and any otologic complaints were noted. Statistical analysis was performed with the Chi-square test, analysis of variance, regression analysis, and confidence interval.

RESULTS

Mesenchyme was found in 2.07% of temporal bones of patients from 5 to 81 years of age. Of these, 92.1% had transitional mesenchyme, whereas 7.9% had pure mesenchyme. Seventy-six percent of the bones showed mesenchyme in the mastoid air cells. In all 3 bones with pure mesenchyme, it was present in the round window niche. Otitis media was associated with residual mesenchyme in 84.2% of the temporal bones. No pattern of regression of mesenchyme with increasing age was observed in temporal bones from patients over the age of 5 years.

CONCLUSIONS

Residual mesenchyme can be present in patients older than 5 years of age and can persist into adulthood, especially in the mastoid air cells. Persistence of mesenchyme is closely associated with evidence of otitis media.

Mucin gene expression in the rat middle ear: an improved method for RNA harvest

Mucins are heavily glycosylated proteins characterized by high molecular weight and heterogeneous structure. Mucin genes are expressed in a tissue- or epithelium-specific manner. Although mucins are known to be important structural components of the mucociliary transport system that protects epithelium against invading microorganisms, very little is known about mucin gene expression unique to the middle ear. This study demonstrated that middle ear messenger RNA specifically hybridized with rat MUC2 and human MUC2 (SMUC-41) complementary DNA probes. MUC3 and MUC5AC mucin genes, dominantly expressed in rodent intestine and trachea, were not detected in the rat middle ears in this study. The middle ear MUC2 messenger RNA harvested by lavage was characterized by a single transcript--unlike its counterpart in intestine and airways, which is characterized by polydispersity--suggestive of a better method for RNA analysis. It was concluded that rat middle ears possess a MUC2 mucin gene or homologue of human MUC2 (SMUC-41).

Expression of intercellular adhesion molecule-1 in rat inner ear due to bacterial otitis media

Expressions of anti-Streptococcus pneumoniae antibody and anti-intercellular adhesion molecule-1 (ICAM-1) antibody in the inner ear were studied immunohistochemically in rats following inoculation of S pneumoniae type 6A into the middle ear cavity. Positive staining with anti-S pneumoniae antibody was detected in the marginal cells of the stria vascularis of rats sacrificed 3 days after S pneumoniae inoculation, but almost no staining was detected in those sacrificed at 14 days. Strong ICAM-1 expression was detected in the basal cell layer of the stria vascularis of rats sacrificed 3 days after inoculation, but the intensity of the staining had decreased by 14 days. These results suggest that the stria vascularis may be a site of the inner ear damage that follows bacterial inoculation into the middle ear cavity. The up-regulated expression of ICAM-1 in the basal cell layer may represent a reaction of the inner ear to the bacterial otitis media.

Tympanoplasty: prudent considerations of silent otitis media and interactions of middle ear and inner ear

Otitis media is a common problem, often with simple, minimally invasive solutions; however, a small subset of patients progress to chronic disease despite provision of standard therapies. The flexible approach to tympanoplasty is a prudent consideration for patients with chronic otitis media, especially children. This article discusses the findings and implications of silent otitis media, interactions of the middle ear and inner ear, and obstructive sites in the middle ear cleft. Tympanoplasty by the flexible approach is described in the context of these findings.

Otitis media with effusion and early sequelae: flexible approach

Patients suffering from chronic otitis media often have a variety of associated disease processes and pathologic conditions. The identification and recognition of these factors are critical to the effective treatment of the condition. This article provides an overview of the conditions associated with chronic otitis media, a detailed review of the disease process, and guidelines for surgical therapy.

Tympanic membrane/middle ear pathologic correlates in chronic otitis media

OBJECTIVE

To correlate pathologic findings of the tympanic membrane with pathologic changes in the middle ear cleft in chronic otitis media.

STUDY DESIGN

Retrospective.

MATERIAL AND METHODS

One hundred-fifty temporal bones from 97 subjects with chronic otitis media (defined as middle ear pathologic changes including granulation tissue, fluid, cholesteatoma, cholesterol granuloma, tympanosclerosis, and ossicular changes) were selected to correlate the presence of these middle ear pathologies with histopathologic changes of the tympanic membrane. The tympanic membrane pathologies included perforation, myringosclerosis, retraction, hemorrhage, fluid-filled cystic spaces, or dilated vessels. Temporal bones were also assessed for atelectasis. Fifty-six normal temporal bones were taken as controls for measurements.

RESULTS

Significant correlations between tympanic membrane and middle ear pathology included myringosclerosis and granulation tissue, myringosclerosis and ossicular pathology, retraction and cholesterol granuloma, retraction and cholesteatoma, retraction and ossicular pathology, perforation and ossicular pathology, and hemorrhage and granulation tissue. Additive effects of some pathologies were also observed. Almost half the bones with middle ear pathology had no associated tympanic membrane pathology, whereas multiple pathologic changes in the tympanic membrane generally showed underlying multiple pathologic changes in the middle ear.

CONCLUSION

When tympanic membrane pathology is detected otoscopically, its presence, alone or in combination, can be a strong indicator of underlying middle ear pathology. However, a normal-appearing tympanic membrane does not exclude the possibility of middle ear pathology. These findings suggest the need for other diagnostic tools such as multifrequency tympanometry and otoacoustic emissions to complement otoscopy for diagnosis of middle ear pathology, especially in a tympanic membrane that appears "normal."

Pneumococcus activation of the 5-lipoxygenase pathway and production of glycoproteins in the middle ear of rats

Pneumococcal otitis media is associated with the production of potent inflammatory mediators (leukotrienes), but the mechanism by which pneumococcus induces production of leukotrienes in the middle ear is poorly understood. In this study, up-regulation of 2 genes that govern the lipoxygenase pathway, cPLA2 and 5-LOX, was observed in rats following inoculation of pneumococcus into the middle ear cavity. Expression of cPLA2 was low, and 5-LOX gene expression was not detected in control animals. Up-regulation of cPLA2 and 5-LOX in middle ear epithelial cells was accompanied by an increase of high-molecular-weight glycoproteins in middle ear fluid and cells. These findings suggest that pneumococcus activates the lipoxygenase pathway by up-regulating expression of the cPLA2 and 5-LOX genes. This, in turn, may stimulate synthesis and secretion of high-molecular-weight glycoproteins that facilitate production of fluid in the middle ear cleft.

[Histopathologically observational study of cartilage-mucosa on the eustachian tube isthmus of temporal bone with otitis media]

OBJECTIVE

To explore the influence of inflammatory pathology change of otitis media upon cartilage-mucosa at the eustachian tube isthmus (ETI).

METHOD

The cartilage-mucosa at ETI and bone-mucosa on the tympanic promontory of 32 temporal bones with otitis media were observated histopathologiclly in comparison with 50 normal temporal bones under light microscopy.

RESULT

The eustachian tube isthmus in all the 32 temporal bone with otitis media and in 50 normal temporal bone were unblocked. The thick-measures and pathology observations of the cartilage-mucosa on ETI in the temporal bones with otitis media revealed there was no obviously inflammatory change and no significantly difference in comparison with the normal control group. But there was obviously inflammatory pathologic change on the bone-mucosa of tympanic promomtory of temporal bone with otitis media. The demarcation line of completely different inflammatory reaction in middle ear cleft was exactly at the connective line between cartilage and bone of eustachian tube.

CONCLUSION

With the specifically histologic structure, the cartilage-mucosa on eustachian tube is possessed of very strong function of natural defence for inflammatory desease, and it almost is impossible to lead to obstruction of eustachian tube by inflammatory influence upon the cartilage-mucosa.

Study of systemic lupus erythematosus in temporal bones

Despite some reports of sensorineural hearing loss with systemic lupus erythematosus (SLE), its pathologic correlate has remained unidentified due to the scarcity of human temporal bone studies. We here present findings in 14 temporal bones from 7 patients with SLE, examined histologically and immunohistochemically for pathologic conditions in the cochlea that might relate to their otologic histories. Blue-staining concretions were seen in the stria vascularis of 6 ears. Most of the cases showed a loss of spiral ganglion cells, with various degrees of hair cell loss and atrophy of the stria vascularis. One ear demonstrated formation of fibrous tissue and bone throughout the cochlea, with complete loss of the membranous labyrinth. Cochlear hydrops was found in only 1 ear. These findings in temporal bones from patients with SLE are discussed in relation to autoimmune disease of the inner ear.

The theory of the trigger, the bridge and the transmigration in the pathogenesis of acquired cholesteatoma

The purpose of the study was to evaluate factors in the otitis media process that could play a role in the pathogenesis of acquired cholesteatoma. The study was divided in two parts: firstly the temporal bones of 75 cats and 15 chinchillas with induced otitis media, and 78 human bones with otitis media were evaluated. Special emphasis was placed on epithelial breaks. These breaks were commonly observed, leaving areas of connective tissue of the mucoperiostium in direct contact with the middle ear effusion. As these changes progressed, the effusion became organized, serving as a bridge for granulation tissue. In later stages these areas became totally or partially covered with epithelium. Areas of epithelial breaks became connected to each other through the organized effusion. Cholesteatomas in humans seem to spread using the connective tissue as scaffolding. Secondly, we reviewed 15 chinchillas in which a chemically modified membrane was placed leading from the external auditory canal to the promontory, through a tympanic membrane perforation. Squamous epithelial migration with cholesteatoma formation occurred through the tympanic membrane perforation, collagen membrane, organized effusion and granulation tissue in 53.5% of the experimental animals. The authors propose the theory that for transmigration of squamous epithelium to occur, a trigger (inflammatory process) and a bridge (granulation tissue and organized effusion) are needed in a predisposed subject.

Endolymphatic sac enhancement surgery in elderly patients with Ménière's disease

Ménière's disease is a pathologic condition of the inner ear that is characterized by vertigo, tinnitus and a progressive loss of hearing. When Ménière's disease is unresponsive to medical treatment and when destructive surgery is not advisable, patients, particularly the elderly, often benefit from endolymphatic sac enhancement, a conservative, nondestructive surgical procedure. We evaluated the outcomes of 62 such patients, aged 65 years and older, who underwent a total of 78 endolymphatic sac enhancements. We assessed their response to surgery by means of a questionnaire, which classified pre- and post-surgical data according to criteria established by the American Academy of Otolaryngology-Head and Neck Surgery. Of the 27 patients who returned questionnaires, 23 reported significant alleviation of vertigo symptoms and 19 said their hearing ability had either improved or was maintained at presurgical levels. Endolymphatic sac enhancement resulted in no mortality, and morbidity was documented in only one patient. We conclude that endolymphatic sac enhancement is a safe and viable treatment for elderly patients with Ménière's disease that is refractory to medical therapy.

Expression of glycoconjugates in human eustachian tubes with otitis media

OBJECTIVES

To characterize glycoconjugate expression in normal human eustachian tubes and study the alterations in glycoconjugate expression found in eustachian tubes with otitis media.

STUDY DESIGN

Using lectin histochemistry, alterations in glycoconjugates were studied in three normal temporal bones, in four temporal bones with mucoid otitis media (MOM), and in five with serous otitis media (SOM).

METHODS

Sections of previously processed temporal bones were decelloidinized, and then incubated with seven biotinylated lectins--WGA, SNA, MAA, BPA, PNA, UEA-1, and LcH--that reflect seven carbohydrate residues of glycoconjugates, respectively: GlcNAc/NeuNAc, NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, Gal beta(1-3) GalNAc, L-fucose, and alpha-mannose residues. Control sections were incubated with inhibitory carbohydrates or without biotinylated lectins.

RESULTS

In the normal temporal bones, five carbohydrate residues in goblet cells and cilia of the eustachian tube demonstrated moderate to strong activity--NeuNAc alpha(2-6)GalNAc, NeuNAc alpha(2-3)GalNAc, GalNAc, Gal beta(1-3)GalNAc, and L-fucose. Two residues demonstrated weak activity--GlcNAc/NeuNAc and alpha-mannose. Temporal bones with MOM revealed increases in sialic acid and alpha-mannose, and a decrease in L-fucose. Residues of carbohydrates in the cilia of bones with SOM were notably decreased, especially for GalNAc, Gal beta(1-3)GalNAc, and NeuNAc alpha(2-6)GalNAc.

CONCLUSIONS

Glycoconjugates in the normal human eustachian tube are rich in GalNAc, Gal beta(1-3)GalNAc, L-fucose, and NeuNAc alpha(2-3/2-6) GalNAc, but low in alpha-mannose and sialic acid. Eustachian tubes from cases with SOM or MOM demonstrated alterations in glycoconjugate expression in cilia and goblet cells, which may reflect disorder of the carbohydrate metabolism during otitis media, especially in SOM.

Silent intratympanic membrane cholesteatoma

OBJECTIVE

To detect the presence of intratympanic membrane cholesteatoma in cases of chronic otitis media.

DESIGN

Two hundred forty-three temporal bones from patients with chronic otitis media were studied for the presence of intratympanic membrane cholesteatoma.

METHODS

Specimens had been previously removed at autopsy, fixed in 10% buffered formalin, decalcified in trichloroacetic acid, dehydrated in a graded series of ethanol, and embedded in celloidin. Sections were cut at a thickness of 20 microm, stained with hematoxylin eosin, and examined using light microscopy.

RESULTS

Intratympanic membrane cholesteatomas were found in five of the 243 temporal bones with chronic otitis media. All temporal bones with intratympanic membrane cholesteatomas were from adult patients. Two patients had bilateral intratympanic cholesteatomas in symmetric quadrants of the tympanic membrane, and the remaining patients with unilateral intratympanic membrane cholesteatoma had been operated on previously for a cholesteatoma of the opposite ear. Other common findings included chronic granulation tissue in the middle ears and mastoids, ossicular pathologic conditions, and in four of the five ears, fluid in the middle ears and/or mastoids.

CONCLUSION

When a white area is observed on the tympanic membrane of patients (especially those with "silent" chronic otitis media), differential diagnosis should include not only tympanosclerosis, but also intratympanic membrane cholesteatoma.

[Silence nature of otitis media]

To explore the silence nature of otitis media, the temporal bone slides from 306 ear with various types of otitis media were studied histopathologically under the light microscopy and their case histories were reviewed at the Otopathology Laboratory, the University of Minnesota Otitis Media Research Center U.S.A. The results showed that 80.97% of otitis media cases lacked clinical symptoms in pathologic process. The subnormal function status of the eustachian tube and the low-degree infection in pathologic process of otitis media probably are basic causes of silence nature of otitis media. The anatomic specialty of ventilation/drainage system of middle ear cleft and the inflammatory pathologic change causing obstruction of internal ventilation/drainage system and leading to the retention of effusion in posterior areas of middle ear cleft may be are important factors for the development of obstinate pathologic change and silence nature of pathologic process of chronic otitis media.

Histopathology of human temporal bone after cis-platinum, radiation, or both

Preserving organs by use of multiple modalities has become protocol in treating squamous cell carcinomas of the head and neck, but cis-platinum and radiation can impair hearing. To determine the effect of cis-platinum, radiation, or a combination of these treatments on the temporal bone, we studied histopathologic slides of 15 human temporal bones: four after cis-platinum, five after radiation, two after combined treatment, and four from normal controls. Hair cells and cells in spiral ganglia were counted in reconstructed organs of Corti. Lumen-to-diameter indexes in arterioles near facial nerves were quantified for four normal controls and seven irradiated patients. Available audiograms were compared. Decreased spiral ganglion cells, loss of inner and outer hair cells, and atrophy of stria vascularis were demonstrated in groups receiving cis-platinum, radiation, and combinations, compared with age-matched controls. Arterioles around facial nerves demonstrated fibrinous clots within the intima, endothelial proliferation, and hypertrophy and fibrosis of vascular walls in smooth muscle. Fibrosis in connective tissue was clearly progressive after radiation. Cis-platinum and radiation can contribute to otologic sequelae, including sensorineural hearing losses, vascular changes, serous effusion, or fibrosis. Prophylactic treatments and techniques to deliver them should be considered for protection of temporal bones and preservation of hearing after oncologic modalities.

Clinical-histopathological correlations of pitfalls in middle ear surgery

Significant anatomical variations within the middle ear are described as well as atypical histopathological findings in 13 selected human temporal bones. Bones studied included such vascular and bony abnormalities as carotid artery canal dehiscence, a high jugular bulb, persistent stapedial artery and facial nerve canal dehiscences. Bones also included obliterative otosclerosis, malleus head fixation and a variety of chronic inflammatory changes and/or sequelae. Those features considered to render cases prone to complications are detailed.

Loss of spiral ganglion cells as primary manifestation of aminoglycoside ototoxicity

Although pulmonary infections caused by Pseudomonas aeruginosa can hardly be eradicated in patients with cystic fibrosis (CF, the most common genetic disease among Caucasians), these patients are mainly treated with intravenous and nebulized tobramycin. Long-term treatment with tobramycin, however, may induce ototoxic effects. We assessed the clinical histories and postmortem temporal bones of six patients with CF for signs of this ototoxicity. Four bones showed typical manifestations of ototoxicity induced by aminoglycosides (AGs): loss of hair cells in the lower turns, and degeneration of ganglion cells. Six bones revealed no loss or scattered loss of hair cells, however, degeneration of the spiral ganglion cells was observed. This suggests that degeneration of the spiral ganglion may occur as a primary manifestation in some cases of ototoxicity due to aminoglycosides. Recent reports have shown that trophic factors (neurotrophins and acidic fibroblast growth factor) interacting with hair cells and the spiral ganglion protect the inner ear from damage. It may be that disturbances in supply of such trophic factors caused degeneration of ganglion cells without loss of hair cells in the cases we studied.

Autoimmune sensorineural hearing loss: a human temporal bone study

PURPOSE

To describe histopathologic findings in temporal bones of a patient whose clinical history suggests a sensorineural hearing loss (SNHL) of autoimmune origin.

MATERIALS AND METHODS

Temporal bones from a patient with a history of ulcerative colitis, leukemia, and SNHL were examined by light microscopy.

RESULTS

Histopathologic findings included: (1) organs of Corti missing or absent in all cochlear turns; (2) cells decreased in spiral ganglia, and lymphocytic infiltration; (3) absence of portions of the spiral prominence; (4) endolymphatic hydrops in basal, middle, and apical cochlear turns and in the saccule and utricle; (5) fibrosis and osteoneogenesis of a scala tympani of the basal turn of the cochlea, the posterior semicircular canal, and the canal of Cotugno; (6) fibrosis of the vestibular aqueduct and endolymphatic sac; and (7) lymphocytes in the endolymphatic sac, perisaccular area, inferior cochlear vein, and Rosenthal's canal.

CONCLUSION

Histopathologic findings in the temporal bones of this patient with ulcerative colitis, sensorineural hearing loss, and vestibular symptoms closely parallel those in a previously reported animal study of autoimmunity and suggest the possibility of a SNHL of autoimmune origin.

Significance of epidermoid formations in the middle ear in fetuses and children

OBJECTIVE

To determine the incidence, size, and location of epidermoid formations (EFs), which have been suggested to be precursors of congenital cholesteatomas, in temporal bones from fetuses and children.

DESIGN

We examined temporal bones from 226 fetuses and children up to the age of 10 years for the incidence, size, and location of EFs.

RESULTS

Twenty-five EFs were identified in middle ears of 3 fetuses, 7 neonates, 9 infants, and 2 children aged 2 and 3 years. There was a male-female preponderance of 5:4. Generally, we saw EFs between the anterosuperior edge of the eardrum and the anterior limb of the tympanic ring, but 4 were below the level of the handle of the malleus. Their widths ranged from 25 to 300 microns. Keratinization was not observed in any EF. Contrary to previous reports, we found EFs not only in ears of fetuses, but also in ears of infants and children.

CONCLUSION

Although EFs may persist in some ears, possibly developing into congenital cholesteatomas, our findings do not provide direct support for this concept.

A new adhesive bonding material for the cementation of implantable devices in otologic surgery

BACKGROUND

Presently, there are no U.S. Food and Drug Administration (FDA)-approved adhesive bone cements for the surgical fixation of prosthetic materials in the middle ear. A promising new cement, 4-META/MMA-TBB opaque resin, has shown remarkable adhesive properties as a bone cement in vivo. The cement is composed of 4-methacryloyloxyethyl trimellitate anhydride (4-META) and methyl methacrylate (MMA) as monomers and tri-n-butyl borane (TBB) as an initiator.

METHODS

An electromagnetic semiimplantable hearing device presently under development was implanted into the middle ear of six cats using 4-META/MMA-TBB resin to cement a titanium-encased magnet to the incus. The animals were subsequently killed (at a mean of 9.6 months) to assess the (temporal bones and specifically the magnet-incus complex in each animal.

RESULTS

The titanium-encapsulated magnet was firmly adherent to all incuses without any failure of the cement-bone interface. Histopathologic examination of the implanted temporal bones demonstrated lack of middle ear inflammation. Transmission electron microscopy of the incuses demonstrated a unique "hybrid layer" in the bone-side subsurface of the bone-cement interface that elucidates the mechanism of interfacial adhesion.

CONCLUSIONS

Our investigation highlights the special biomechanical properties as well as the biocompatibility of 4-META/ MMA-TBB resin that make it an attractive bone-bonding agent for use in otologic surgery, including its potential usefulness during ossicular reconstruction.

Outgrowing schwannomas arising from tympanic segments of the facial nerve

PURPOSE

Although there have been numerous reports of clinical cases of facial nerve schwannoma, histopathologic studies of its early stages of development are rare. The purpose of this study was to describe the incidence, origin, and pathology of small, asymptomatic schwannomas of the facial nerve.

MATERIALS AND METHODS

Fifteen hundred twenty-six ears from the human temporal bone collection of the Otitis Media Research Center Otopathology Laboratory at the University of Minnesota were studied under light microscopy.

RESULTS

Twelve bones with morphologic indications of type A Antoni tissue that mimics facial schwannoma in the tympanic cavity were selected. The 12 ears were from nine individuals with asymptomatic histories. The twelve schwannomas developed from perineurium at dehiscences in the facial canal near the oval window, forming defects in the epineurium by growth of Schwann cells downward and outward toward the stapes. No obvious compressions or lesions within fibers in the facial nerve were observed.

CONCLUSION

Because these tumors grow slowly without hearing loss or facial nerve symptoms, they may be mistaken for granulation tissue during surgery for chronic otitis media.

Residual mesenchyme in temporal bones of children

The role of mesenchyme in the temporal bone is still poorly understood. A microscopic study of residual mesenchyme was undertaken in temporal bones of children from birth to 5 years of age. Residual mesenchyme was found to be located in the mastoid antrum and epitympanum more often than in the mesotympanum. The amount of mesenchymal tissue remaining in the temporal bones decreased with increasing age. Persistence of mesenchyme in the temporal bone was related to congenital morphologic ear anomalies and syndromes. There was also an association evident with pulmonary disease, but not with congenital heart defects. Persistent mesenchyme was also found to be significantly associated with chronic middle ear inflammation, and in cases of unilateral otitis media the ear with otitis media had more residual mesenchyme than the non-otitis media ear.

Temporal bone study of Down's syndrome

OBJECTIVE

To study temporal bone histopathologic characteristics of the inner ear and middle ear cleft of patients with Down's syndrome.

DESIGN

Sixteen temporal bones from eight patients with Down's syndrome were studied. Ten temporal bones from subjects without pathologic ear lesions but with congenital heart disease served as controls. The two-dimensional graphic reconstruction method proposed by Guild and modified by Schuknecht was used to study the cochleas; measurement of the vestibules was based on Igarashi's method.

SETTING

The temporal bone collection of the Otitis Media Research Center, Department of Otolaryngology, University of Minnesota School of Medicine, Minneapolis.

RESULTS

Six bones showed short cochlea, and four of six had Mondini's cochlea. The overall cochlear lengths in this study group were notably shorter than those of the controls. The spiral ganglion cell population and two of three vestibular dimensions also were notably less than the controls. Middle ear findings included residual mesenchyme, stapes abnormality, otitis media, and large facial canal dehiscence.

CONCLUSIONS

The difficulties encountered in rehabilitation of patients with Down's syndrome caused by mental retardation can be compounded by the hearing loss caused by middle and inner ear abnormalities. A complete evaluation of hearing loss and therapy before starting the rehabilitation gives the most favorable outcome.

Developmental anatomy of the supratubal recess in temporal bones from fetuses and children

The supratubal recess (STR), located superior to the bony eustachian tube and anterior to the attic and often the site of disease, is clearly separated from the attic by the presence of a bony partition. Its anatomic development in childhood, however, remains nuclear. We reviewed serial horizontal sections of fetal and children's temporal bones from the collection of the Otopathology Laboratory, University of Minnesota. Apparently, upward expansion of the bony eustachian tube begins at a late fetal stage and continues throughout childhood, thus forming the STR. Our finding that the STR had already developed in temporal bones without pneumatization of petrous bone suggests that its formation is independent of the air-cell system. Absorption of mesenchymal tissue in the STR tends to be slower than elsewhere in the temporal bone. Surrounded solely by petrous bone, the STR seems, both developmentally and anatomically, a distinctive compartment of the middle ear.

Audiological profiles and Menière's disease

Pure-tone audiograms of 501 patients with preoperative Menière's disease were analyzed. Age of onset and incidence of bilaterality were studied. The most common audiogram was the peak-type (50.26%), next the falling-type (26.26%), and then the dip-type (9.24%). Although few papers mention this peak audiogram, we suggest it is a diagnostic feature of Menière's disease. Average age of onset was 42.59 years; this did not differ from males to females. Prevalence in females exceeded that in males by about 4:3. The disease was bilateral in 31.13%. Generally, those with better hearing thresholds at the first examination had less tendency to develop bilaterality. Age of onset was not significantly correlated with bilaterality.

Normal and metastatic melanin in the temporal bone

PURPOSE

Malignant melanoma is known to metastasize to the temporal bone. However, melanocytes exist in the normal inner ear and may be difficult to distinguish from metastatic melanotic cells. This study describes distribution of normal melanin in the ear and metastatic melanoma to the temporal bone.

MATERIALS AND METHODS

Normal melanin distribution is described in 48 temporal bones from White (18), Native-American (19), and African-American (11) individuals and metastatic melanoma to the temporal bone is described in four cases (seven temporal bones). Temporal bones were removed at autopsy, fixed in 10% buffered formalin, and processed for routine celloidin embedding. Sections were cut at a thickness of 20 microns and every tenth section was stained with hematoxylin-eosin for light microscopic evaluation.

RESULTS

Normal melanin was found in the inner ear, mainly around terminal neural structures and blood vessels, and occurred in greater quantities in African-American individuals. Metastatic melanotic cells reached the temporal bone by hematological dissemination, and by neural invasion from the central nervous system. No correlation was found between histopathological findings and clinical symptoms of patients.

CONCLUSIONS

Metastatic melanoma to the temporal bone may be seen in the same areas as normal melanin. They may also be observed in bone marrow cells of the petrous bone and along the course of nerves of the internal auditory canal and cochlear vestibular labyrinth, either by following neural sheaths or blood vessels that run along the nerve. Metastatic disease to the temporal bone is often asymptomatic, or it may present with uncharacteristic symptoms that may delay diagnosis.

Otitis media (silent): a potential cause of childhood meningitis

Sixteen temporal bones from 8 infants with otitis media, who died of meningitis, and 6 controls from infants with only otitis media, were studied histologically. All bones contained middle ear effusion and residual mesenchyme, but, unlike the controls, the meningitic cases showed considerable histopathological tissue changes of chronic and acute otitis media and chronic inflammatory cells in the round window membrane and within the perilymph, the modiolus, and the cochlear aqueduct, suggesting the latter as likely portals from the inner ear to the meninges. Since all tympanic membranes were intact and 3 were histologically normal, this silent route of infection warrants medical vigilance.

Micropathologic changes of pars tensa in children with otitis media with effusion

Clinical studies have supported a relationship between otitis media with effusion in children and chronic otitis media in adults. Although clinical studies are numerous, relatively little is known about the histopathologic changes of the tympanic membrane in otitis media with effusion. Tympanic membranes were taken from the intermediate zone of the anteroinferior quadrant of the tympanic membrane during surgery for placement of tympanostomy tubes in 30 children (age range, 4 to 10 years) who did not show any improvement after 3 months of conservative treatment for otitis media with effusion. Control specimens were taken from normal temporal bones at autopsy. All specimens were observed with light and electron microscopy. Histologic degeneration of the tympanic membrane of patients with otitis media with effusion occurred most often in the lamina propria and the submucosal layer. There was an increase in the thickness of the tympanic membrane as a result of edema and fibrosis of the submucosal layer. A decrease in the thickness of the outer and inner fibrous layers occurred in the lamina propria. The histopathologic changes observed in the lamina propria may result in a change in the elastic properties of the tympanic membrane.

The temporal bone in multiple myeloma

Multiple myeloma is a malignant disease of the skeleton. Anatomically, any bone may ultimately come to be involved in a given case. In a literature review, no published series of temporal bone findings have been reported. In this study, oto-histopathologic changes associated with multiple myeloma are analyzed and reported in 15 temporal bones from 8 patients. The bone marrow of 13 temporal bones was involved by the tumor. Osteolysis was evident in 11 temporal bones. Serous otitis media (SOM) or purulent otitis media (POM) was seen in 13 ears with 12 showing mastoid effusions. Eight ears exhibited pathological changes in inner ears, including degeneration of the organ of Corti, atrophy of stria vascularis, decreased ganglion cells, and labyrinthine hydrops. The inner ear changes were most severe in 2 patients who had otologic symptoms. Infiltration of myeloma cells was not apparent in the middle ear mucosa or the inner ears.

Prevalence of microfissures in the human temporal bone: a report of 1000 temporal bones

A total of 1000 human temporal bones were studied to determine the prevalence of two microfissures: 1. the one between the facial canal and the vestibule, 2. the microfissure between the round window niche (RWN) and the posterior semicircular canal (PSC). Additionally, this study compares the prevalence according to temporal bone age and sex. The microfissure between the facial canal and the vestibule was observed in 470 (47%) temporal bones, with a bilateral presence of 77.2%. The prevalence of this microfissure increases linearly with age. It was not found in any bone within the 0 to 2 age group. It was present in 3 (7.3%) bones from the 2 to 9 age group, as opposed to 374 (54.8%) bones from the 40 and over group. The microfissure between the RWN and the PSC was detected in 915 (91.5%) temporal bones. This second microfissure was found to be an overwhelmingly bilateral entity. The prevalence of this other microfissure also increases with age. This microfissure was also not present in any temporal bone within the 0 to 2 age group. It was found in 28 (68.3%) bones from the 2 to 9 age group, in contrast to 678 (99.4%) temporal bones from the 40+ group.

New developments in treating otitis media

Treatment of otitis media has changed over time as the disease has become better understood and as clinical experience and technology have expanded and grown. Successful treatment depends on accurate definitions and classifications of types of otitis media. An awareness of the pathogenic and pathologic correlates of otitis media enhances accurate diagnosis and improves the results of treatment. An understanding of the otitis media continuum also assists in management. On the basis of studies largely emanating from the University of Minnesota's Otitis Media Pathogenesis Research Program, we here highlight definitions, classifications, and diagnosis of the otitis medias, and medical treatments of these various clinical and pathologic entities and their sequelae.

Surgical advances in treating otitis media

Surgical methods of treating otitis media and its sequelae are discussed, according to the classification of otitis media presented in an earlier report. Surgical management of otitis media with effusion and recurrent purulent otitis media includes myringotomy and use of ventilation tubes. Occasionally, otitis media with effusion will lead to structural and other pathologic changes in the middle ear, and conservative treatments such as use of medication or tubes will not suffice. Indications and methods for exploratory tympanotomy and reconstruction of the middle ear are discussed. In such instances, tympanoplasty can be used to the patient's benefit. Chronic otitis media with mastoiditis, defined by the presence of intractable pathologic tissue, generally requires surgical correction. Classic methods include simple mastoidectomy, modified radical (Bondy) mastoidectomy, and radical mastoidectomy. Current classifications of procedures would also include closed-cavity tympanomastoidectomy, open-cavity tympanomastoidectomy, and intact-bridge tympanomastoidectomy (a combined approach). The diagnostic and surgical approach to silent or subclinical otitis media is discussed. Diagnosis and treatment of sequelae of otitis media, including sequelae in the middle ear and, less commonly, in the inner ear, are discussed.

Prevalence of carotid canal dehiscence in the human middle ear: a report of 1000 temporal bones

A total of 1000 human temporal bones were used to study the prevalence of carotid canal dehiscence, microdehiscence, and thin bony coverage. Additionally, this study compares the prevalence according to sex and temporal bone age. A carotid canal dehiscence was detected in 77 (7.7%) bones. It was present bilaterally in 23.2% of the paired temporal bones. The prevalence of carotid canal dehiscence decreases with increasing temporal bone age. It was found in 10 (15.9%) bones in the younger than 2 age group, as opposed to 43 (6.3%) bones from the 40 and older group. The concept of microdehiscence of the carotid canal is introduced. A carotid canal microdehiscence was found in 74 (7.4%) bones. Microdehiscences were noted to occur bilaterally in 12.3% of the paired bones. The prevalence of carotid canal microdehiscence also decreases with increasing temporal bone age. It was detected in 7 (11.1%) bones in the younger than 2 age group, in contrast to 51 (7.5%) bones in the 40 and older group. A total of 134 (15.5%) temporal bones were found to have a thin bony coverage, without the presence of a dehiscence or microdehiscence. The prevalence of thin coverage was noted to increase linearly with age. A thin carotid canal was found in 2 (8.3%) bones from the younger than 2 age group, whereas 113 (17.3%) temporal bones from the 40 and older group exhibited this entity. To the best of our knowledge, this is the first systematic study of histologic sections of a large number of temporal bones that looks at these entities.