Mucopolysaccharidosis I-H (Hurler's syndrome) and human temporal bone histopathology

Six temporal bones from three patients with mucopolysaccharidosis I-H are described. All three patients were diagnosed as having mucopolysaccharidosis I-H by enzyme analysis, and all fit the phenotypic criteria of this disease. Family histories of the three cases described were negative for mucopolysaccharide-storage diseases. All three of the patients suffered chronic recurrent otitis media from infancy through death. Common histopathologic findings include otitis media, residual mesenchyme in the round window niche, partial occlusion of the middle ear cavity, and basophilic concretions within the stria vascularis. The common severe histopathologic changes observed in this study and similar findings in the temporal bones described in other studies lead the authors to believe that ear involvement in this disease may be more common than was previously suspected.

The human round window membrane. An electron microscopic study

The normal adult human round window membrane was examined by transmission electron microscopy. The membrane consists of the following three layers: (1) an outer squamous epithelial layer with an underlying basement membrane; (2) a middle fibrous layer containing collagen, elastin, fibrocytes, vessels, and nerves; and (3) an inner layer of mesothelial cells. Mucosal membrane veils that cover the round window membrane, forming "false" round window membranes, are also described. These membranes are also three layered, including (1) an outer epithelial layer with an underlying basement membrane, (2) a middle fibrous layer containing collagen, elastin, fibrocytes, vessels, and nerves, and (3) an inner epithelial layer with an underlying basement membrane. Ultrastructural differences between these two structures are discussed.

The round window membrane: otological observations

The membrane of the round window serves as a barrier between the middle and inner ear and has a well-established role in cochlear physiology. It is important in many otological conditions: otitis media, otosclerosis, trauma, sequelae to drugs reaching the middle ear, tumors, congenital dysplasia, sudden deafness. We here describe the first electron microscopic findings in round window membranes from adult humans, and various conditions in reference to these findings. Since surgical lesions are made in this membrane during cochlear implantation, and by some otologists in treating vertigo, preliminary findings of a lesioning experiment in animals are presented. Interestingly, early healing resulted from a mesothelial cellular reaction in the adjacent scala tympani, with formation of clots, while in the middle ear the epithelial cellular layer sealed the edges of the perforation, leading to formation of an indentation ("pocket"). Subsequently, the middle layer of the membrane contributed to healing.

Meniere's syndrome and otitis media

We here present a clinical study of 37 patients with Meniere's syndrome. Meniere's syndrome can occur subsequent to and in some cases simultaneously with chronic otitis media. When otitis media which has occurred many years earlier in childhood becomes inactive, leading to sequelae of Meniere's later in life, full-blown Meniere's symptom-complex with vertigo tends to occur; whereas when active chronic otitis media accompanies Meniere's, cochlear Meniere's syndrome tends to predominate. Endolymphatic hydrops is described in pathological cases of labyrinthitis and in 11 human temporal bone cases where there is evidence of chronic otitis media in the absence of visible labyrinthitis. A discussion of pathogenic factors includes considerations of quantity of endolymph due to hypodevelopment of the endolymphatic duct and sac related to mastoid hypocellularity and otomastoiditis in childhood and to other endolymphatic malabsorptions and also considerations of endolymph quality which can influence endolymph production as well as absorption.

Trauma and Meniere's syndrome

Thirty-seven patients who developed Meniere's syndrome following acoustic (18) and physical (19) trauma are described and discussed. Histopathologic characteristics, which appear identical to idiopathic Meniere's disease, are described in a gentleman who developed Meniere's syndrome after head trauma. Concepts of cause and effect relationships and pathogenesis are discussed.

Intact bridge tympanomastoidectomy (I.B.M.)--combining essential features of open vs. closed procedures

In recent years, closed cavity intact wall tympanomastoidectomy or combined approached tympanoplasty--(CAT)--has been described and recommended by many. The pendulum now appears to be swinging back again to open cavity tympanomastoidectomy. Pertinent literature in this regard is reviewed. In all patients with chronic otitis media and mastoiditis with intractable tissue pathology, the primary objective is total eradication of disease with the achievement of a dry safe ear while a concomitant but secondary objective is hearing retention and restoration utilizing tympanoplasty techniques. Over a three-and-a-half year period we have utilized a one-stage procedure which provides the desirable objectives of both open and closed cavity tympanomastoidectomy called intact bridge tympanomastoidectomy (I.B.M.). The salient features include: (1) good exposure, as in open cavity tympanomastoidectomy; (2) maintaining and widening the middle-ear space by bony bridge retention and facial buttress sculpturing, to enhance grafting and ossiculoplasty such as TORP or PORP, as in canal up tympanomastoidectomy; (3) enhancement of mastoid obliteration for large cavities, by blocking the aditus with bone paté or cartilage and by providing a separation between middle ear and mastoid. Specific methods, techniques and results are presented and discussed. The results have been gratifying to date. In comparison to intact wall tympanomastoidectomy, this one-stage operation avoids the cost and discomfort of a second and sometimes third stage; surgery for recurrent pathology has been avoided and hearing results have been at least comparable if not improved.

Children with persistent otitis media. Audiometric and tympanometric findings

Audiometric and tympanometric findings were compared among 129 patients with clinically manifest persistent otitis media (OM) with effusion. Ears with thick effusion (mucoid OM) had significantly larger air-bone gaps and higher prevalence of flat tympanograms than either of the thin effusion types (purulent [POM] or serous OM [SOM]) or ears with no effusion (dry). Ears with thin effusion (POM and SOM) had similar air-bone gaps, thresholds for air and bone conduction, and prevalences of flat and underpressure tympanograms. Ears with no effusion had significantly smaller air-bone gaps, slightly poorer bone conduction thresholds, and lower prevalence of flat tympanograms than ears with effusion (MOM, POM and SOM). Ears with clinically manifest OM and no effusion at tympanocentesis appear to represent patients with a spontaneously resolved episode of OM with thin effusion (POM or SOM) or with ears that evacuated during anesthesia prior to tympanostomy.

Pathogenesis of Meniere's disease and Meniere's syndrome

Meniere's disease can only be studied in patients, since it does not occur spontaneously in animals nor can it be induced in them. However, aspects of the disease such as endolymphatic hydrops can be usefully studied in animals. A study of the natural history (epidemiology) of Meniere's disease demonstrated the three major symptoms (triad) to be vestibular symptoms, auditory symptoms, and aural pressure. Bilaterality occurs in at least one out of 3 patients, and may approach 50% over full lifespans. Aural pressure (74.1%) was common, as was positional vertigo (85.9%) during and/or between attacks. Clinical variants such as vestibular Meniere's disease could persist for 25 years or more. Understanding the pathogenesis of Meniere's requires a study of known and unknown causes. In this study, Meniere's disease (cause unknown) was differentiated from Meniere's syndrome (cause known). Meniere's disease or syndrome can occur years after some inciting cause; thus all forms of Meniere's can be considered to have a delayed onset. Meniere's syndrome can occur as a sequel to syphilis, otosclerosis, infection (for example otitis media), or trauma. Endolymphatic hydrops explained on the basis of quantity and quality of endolymph is found in all forms of Meniere's disease and syndrome. Representative cases and pathological examples are discussed. Hydrops of the pars inferior (cochlear duct and saccule) is the most important finding in Meniere's disease. In some (but not most) cases, ruptures of the membranes are seen. The saccule can distend into the lateral semicircular canal. Symptomatic attacks are explained on the basis of both physical and biochemical phenomena. This study discusses concepts of pathogenesis of the disease, finding both theories of longitudinal (slow) and radial (fast) flow to be operational. Longitudinal flow, however, appears to be more important than radial flow, especially in advanced Meniere's where perilymph in the scala vestibuli and vestibule disappears and is replaced by membranous labyrinth. Meniere's disease (idiopathic) and Meniere's syndrome (cause known) probably occur as a result of endolymphatic absorptive dysfunction (the site being endolymphatic duct and sac). Hypocellularity of the mastoid and periaqueductal air cells, hypodevelopment of Trautmann's triangle, and anterior displacement of the lateral sinus are likely to be important findings associated with developmentally dysfunctional absorption of endolymph.(ABSTRACT TRUNCATED AT 400 WORDS)

The normal chinchilla round window membrane

The chinchilla round window membrane consists of three layers: (1) an outer epithelial layer facing the middle ear cavity with tight junctions and numerous desmosomes, (2) a middle connective-tissue layer consisting of fibroblasts, fibrocytes, collagen, elastin, capillaries, and myelinated and unmyelinated nerves, and (3) an inner cellular layer with thin cytoplasmic processes containing numerous micropinocytotic vesicles and dark granules similar in form to alpha-type glycogen. Studies of the fine structure of the normal round window membrane in animals are prerequisites to understanding the role of the round window membrane in both normal function and in diseased states such as otitis media.

Meniere's disease and the peak audiogram

Pure tone audiograms of 300 patients with Meniere's disease and 400 patients without Meniere's disease were compared for prevalence of a high-frequency peak configuration. Prevalence rate of 42% for a peak audiogram was observed in ears diagnosed with Meniere's disease compared with 6% for patients with cochlear hearing loss not attributed to Meniere's disease, and 7% for normal hearing patients. Prevalence of the peak audiogram in patients with Meniere's disease was significantly greater than either of the patient groups without Meniere's disease. Prevalence of peak audiogram was affected by duration and bilaterality of Meniere's disease, but not by the degree of hearing loss. A classification system is proposed for describing the peak audiogram based on the severity of the peak configuration and the degree of hearing loss.

Epidemiology of otitis media with effusion in children

The recently accepted international classification for otitis media was applied to a study population of 898 children less than 12 years of age having otitis media with effusion persisting at least three months. Mucoid effusion was aspirated from 48% of ears, was found more often in younger than older patients, was more often bilateral, and was a more stable state during longitudinal observation than was serous otitis media or purulent otitis media (POM). Serous otitis media occurred in only 10% of ears, but was found more often than in younger patients; POM was found in only 7% of ears. Otoscopy did not distinguish among the three effusion types. Known middle-ear pathogens were cultured more often behind red and bulging tympanic membranes from these cases of chronic effusion than behind membranes lacking these characteristics. These observations provide an epidemiologic and clinical base for further investigations of these otitis media types.

Exploratory tympanotomy revisited

The history of exploratory tympanotomy is somewhat obscure. Methods and findings of exploratory tympanotomy were described and assessed for unexplained conductive and occasional sensorineural hearing losses. Of 316 recent cases positive findings leading to diagnosis and therapy occurred in all 250 cases of conductive hearing losses and in 43 of 63 cases of sensorineural hearing losses. In decreasing order of occurrence findings were sequelae of otitis media, otosclerosis, oval and round window changes including perilymph leakage, congenital and traumatic fixation and disarticulation of ossicles. These observations and indications are discussed.

Ganglia and ganglion cells in the middle ear. Their presence in the human and the cat

One hundred human and 100 cat temporal bones were studied for the presence of ganglia and/or ganglion cells. These structures were found at the following two main locations: (1) the promontory wall, both anterior to and below the stapes, and (2) the vertical portion of the facial nerve. In the cat, additional ganglion cells were found within the capsule of the musculus tensor tympani, proximal, medial, and lateral to muscle fibers. The consistent presence of ganglion cells in the mucoperiosteum suggests that they play important roles in the middle ear itself; their presence in the vertical portion of the facial nerve supports the concept that the parasympathetic innervation of the parotid gland is not exclusively via the ninth nerve and/or lends anatomical support to atypical facial pains.

The round window membrane following application of staphylococcal exotoxin: an electron microscopic study

The round window membrane has been considered as a pathway for the passage of toxic substances from the middle ear cavity to the vestibular labyrinth in cases of otitis media. To determine the role of the round window membrane in this passage, chinchillas were given intrabullar inoculations with staphylococcal exotoxin and the round window membranes were examined electron microscopically. We observed cytoplasmic vacuolization, intercellular edema, cellular and nuclear swelling of the surface epithelia and polymorphonuclear leukocyte (PMN) infiltration of the fibrous layer. Light microscopic observation of the labyrinth revealed PMN infiltration of the most basal portion of the scala tympani. These findings demonstrate a chemotactic effect of the toxin for PMNs and support the concept of the round window membrane as an important avenue of entry.

Panel of Menière's disease. Endolymphatic sac enhancement surgery for Menière's disease: an extension of conservative therapy

It is out hypothesis that the primary goal of endolymphatic sac surgery in cases of intractable Menière's disease or syndrome is for the purpose of enhancing absorption of endolymph. Our experience includes 251 cases over a period of 15 years. In this report we discuss rationale, current methods, and results in a series of 176 cases since 1974.

Clinical evaluation of Ménière's disease

A retrospective review of 211 consecutive patients with classic Meniere's disease was performed to determine the efficacy of diagnostic studies. The patients' ages averaged 47 years and ranged between 8 and 86 years. Females outnumbered males 1.3 to 1. Left and right ears were affected with equal frequency and, in 12% of patients, the disease was bilateral. Audiologic patterns were flat in 42%, rising in 7%, peaked in 32%, and sloping downward in the remaining 19%. Electronystagmography was normal in 21% of the patients and demonstrated canal paresis in 65% and directional preponderance in 14%. Studies of glucose metabolism were abnormal in 2 of the 204 patients tested. The 7 patients not tested had a previous diagnosis of diabetes mellitus. Thyroid function studies were abnormal in 1 of the 208 patients studied. The 3 patients not studied were known hypothyroid. FTA-abs was positive in 12 patients and special radiographic studies of the petrous apex were normal in all cases. Conclusions suggested by this study are that audiology, electronystagmography, and treponemal antigen tests for syphilis are cost effective in evaluating patients with Meniere's disease. Studies of glucose metabolism and thyroid function, however, are probably not indicated in patients without a history suggestive of a metabolic disorder and specialized radiographs of the petrous apex should be reserved for patients suspected of having acoustic neuroma.

Experience with tympanoplasty for atelectatic ears

Atelectasis is, unfortunately, still a common sequela of otitis media with effusion (OME)--including serous otitis media (SOM) and mucoid otitis media (MOM). When atelectatic ears provide a functional deficit, i.e., a conductive loss of sufficient magnitude or a residual conductive loss after aerating the middle ear with ventilation tube or early or strongly suspected attic cholesteatoma, a simple corrective procedure has been used which has stood the test of time. The procedure as well as experience with 51 patients (60 ears) will be described and discussed. The procedure consists of re-establishing the mesotympanic space, strengthening the tympanic membrane by an underplant fascial graft, cutting the tensor tympani, extirpation of any disease, re-establishment of ossicular mobility and continuity and the insertion of a ventilation tube in the anterior drumhead remnants along with silicone rubber sheeting and a moist Gelfilm implant. Methods and results are discussed.

Passage of albumin from the middle ear to the inner ear in otitis media in the chinchilla

A study of the permeability of the middle ear-inner ear interface for macromolecules was carried out in chinchillas with open and obstructed eustachian tubes utilizing tritiated human serum albumin and immunoelectrophoresis. Tritiated albumin was placed in the round window niche area or normal animals and animals in which the eustachian tubes had been obstructed for 24 hours or 14 days. The tritiated albumin was allowed to remain in the middle ear cavity for 24 hours, Samples of middle ear effusion, perilymph, blood and cerebrospinal fluid were collected and measured for radioactivity. Radioactivity was demonstrated in the perilymph. Samples of middle ear effusions and perilymph were also studied by immunoelectrophoresis with goat antihuman albumin. Albumin placed in the round window niche of an experimental animal could be recovered unchanged in the perilymph. The results suggest a pathophysiologic explanation for the association of otitis media and sensorineural hearing loss or endolymphatic hydrops.

Otitis media with perforation of the tympanic membrane: a longitudinal experimental study

Despite the high incidence and prevalence of otitis media, its pathogenesis is not thoroughly understood. In an effort to provide a better understanding of this disease, experimental animal models have been developed which corroborate the changes observed in humans. In this study a new factor was added: tympanic membrane perforation 1 week after Eustachian tube obstruction. Twelve cats were divided in 4 even groups, and sacrificed at 1 and 2 weeks, 1 and 3 months after perforation, and their temporal bones were studied. Findings revealed an early massive reaction of the mucoperiosteum with granulation and polypoidal tissue formation which filled a considerable portion of the middle ear cavity. Polypoidal changes involved the stapediovestibular joint, possibly explaining the cases of stapes fixation found at tympanomastoidectomy procedures for chronic otitis media. Cholesterol granulomas with the classic characteristics as described in humans were observed in all animals at 3 month periods. These were preceded by clefts in the effusions, at 1 month, containing red blood cells. These clefts were considered as probable precursors of cholesterol granuloma formation. The association of endolymphatic hydrops, round window membrane changes, and otitis media without purulent labyrinthitis was observed; however, it was felt that the paucity of animals precluded any definite conclusions.

Ototoxicity of propylene glycol in experimental animals

The ototoxicity of antibiotics given either systemically or topically has been recently recognized. However, the ototoxicity of topically applied alcohols and other solvents used as vehicles for drugs has not been well recognized. One of the most common solvents, propylene glycol, was chosen for this study, and this agent in various concentrations was instilled into the middle ear of guinea pigs and chinchillas for various periods of time. Its effect on the function of the cochlea was studied as well as the histopathologic changes in the temporal bones. Deterioration of the cochlear microphonics and the endocochlear direct current potential was found. A 10 per cent solution applied for six days caused a reduction in the cochlear microphonics. Fifty per cent or stronger solution always caused a reduction in the cochlear microphonics. The deterioration in the cochlear microphonics persisted one month. Dose related changes in the endocochlear potential were noted. Morphologic changes were severe and included granulation tissue in the middle ear and destruction and ossification of the auditory bulla and bony cochlea. Propylene glycol should not be used in the ear that has a perforation of the tympanic membrane.