Mid-frequency sensorineural hearing loss: aetiology and prognosis.

OBJECTIVES: An audiometric finding of mid-frequency sensorineural hearing loss (MFSNHL), or a U-shaped pattern, is uncommon. The objective of this study is to investigate the aetiology and prognostic significance of MFSNHL. DESIGN: Tertiary academic referral centre-based retrospective case review and review of audiograms to determine the prevalence of this audiometric finding. METHODS: Patients with a pure tone threshold average at 1, 2, and 4 kHz at least 10 dB greater than the average at 0.5 and 8 kHz were included in this study; 35 patients met these criteria. The mean age of the patients was 34.6 years old (range 4-71 years). Twelve patients (33 per cent) were under 18 years of age. Serial audiograms were obtained for 14 patients. The notes were reviewed for any pertinent otologic history, subsequent diagnoses, management and disease course. RESULTS: The prevalence of MFSNHL in this practice setting is less than 1 per cent. The average hearing threshold in the mid-frequencies was 44 dB, which was 17 dB and 20 dB lower than at 0.5 Hz and 8 kHz, respectively. The pure tone average (0.5, 1, 2 kHz) was 40 dB. Sixteen patients (44 per cent) required amplification. Of all patients, 22 had hereditary hearing loss, eight had idiopathic hearing loss, and five adults had vestibular schwannomas. CONCLUSIONS: MFSNHL is an infrequent audiometric finding. The great majority of these cases are of presumed hereditary or idiopathic aetiology, although 22 per cent of adults had vestibular schwannomas. This series presents the causes and prognosis of this audiometric pattern.

Chronic myringitis: prevalence, presentation, and natural history.

OBJECTIVE: The aim of this study was to examine the clinical presentation and natural history of chronic myringitis (CM). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Chronic myringitis is defined as a loss of tympanic membrane epithelium for >1 month without disease within the tympanic cavity. Seven hundred fifty patient records were reviewed to determine the prevalence of CM in an academic otology practice. The records of 40 patients (45 ears) with CM seen between 1995 and 1999 inclusive were reviewed. MAIN OUTCOME MEASURES: The series was reviewed with attention to previous medical and otologic history, the nature and duration of symptoms, the physical findings, and management. RESULTS: The prevalence of CM was found to be -1% (approximately one fourth as common as cholesteatoma). Symptoms were often present for many years before the diagnosis of CM, with CM often mistaken for chronic otitis media. Sixty percent of patients had undergone previous otologic procedures. There did not appear to be an association between CM and systemic disease. Physical findings were varied, with granulation tissue and tympanic membrane perforations often occurring transiently. The clinical course of CM is typified by recurrent episodes of symptoms, often interspersed with long asymptomatic periods. A subset of CM can result in an acquired atresia. The most effective treatment appeared to be prolonged topical medications, surgery being reserved for only the most refractory cases. CONCLUSIONS: Chronic myringitis is often mistaken for chronic otitis media. Such confusion prolongs the initiation of appropriate management and sometimes leads to needless tympanomastoid surgery. The otologist should be aware of this clinical entity and its varied presentation.

[Retraction of the endolymphatic membranes in temporal bones of the Wittmaack and Tufts collections]. / Retraktion der endolymphatischen Membranen in Felsenbeinen der Wittmaack-Sammlung und der Tufts Collection.

BACKGROUND: In histologic studies, the volumetric status of the intralabyrinthine fluids is judged by the position of the endolymphatic membranes. Bulging of the membranes, commonly known as endolymphatic hydrops, is assumed to be caused by excess of endolymph. The opposite situation, retraction of the membranes is, however, only incidentally described and relatively little attention has been paid to its significance. Almost one hundred years ago Wittmaack described retraction of the endolymphatic membranes, which has since been considered to be preparation artifact--a concept that essentially remains unchallenged. To test the validity of this long premise, we examined two sets of temporal bones from different centers. MATERIAL AND METHODS: We studied the following collections: 1. The Wittmaack collection in Hamburg, Germany. The original material of 67 temporal bones (patient ages 0-92 years, average age 35.2 years) on which Wittmaack based his opinions. 2. For comparison and to exclude age related phenomena, 125 temporal bones from 73 children between the ages newborn to ten years (average age 13.4 months, median 1.5 months) from the temporal bone collection of the Department of Otolaryngology Tufts University School of Medicine. All specimens were studied by light microscopy. Retraction was defined as depression of Reissner's membrane toward the stria vascularis and the Organ of Corti in more than one cochlear turn and was graded into mild, moderate and severe. Additionally the saccule, utricle and semicircular ducts were examined for collapse. RESULTS: The reevaluation of the 67 temporal bones described by Wittmaack, including those of 7 children below the age of 10 years, showed retraction of Reissner's membrane in 81% compared to 33% of the temporal bones from the Tufts collection. In contrast to the high incidence of retraction in the cochlear duct, fewer saccules (12%) and utricles (4%) were collapsed in the Tufts collection. In the Wittmaack collection no significant differences between the underlying diseases were found, however in the Tufts collection the group of children who suffered from extracochlear infections and malignancies had a higher frequency of retraction. CONCLUSION: Mild retraction might be to some extent physiologic or even artifactual. Severe retraction, however, is a definitive finding that is a part of a local or regional otopathologic process. Of material, it is quite possible that Wittmaack's original observations of what he called "hypotonic collapse" was of viral origin (viruses were not known during Wittmaack's time), ototoxicity or even of genetic origin.

Vascular variations of the inner ear.

Vascular anomalies of the inner ear have been documented in only a few isolated case reports. The goal of our study was to describe, qualify and quantify vascular variations of the inner ear in 122 temporal bones from 64 pediatric subjects aged between 0 and 10 years. The average age was 11.6 months. Horizontal sections of the temporal bone, examined by light microscopy, revealed vessels coursing freely through the perilymphatic space of the cochlea, especially in the apical turn. Other findings included abnormally wide vessels in the stria vascularis as well as a vascular malformation of the internal auditory canal. Our study demonstrated more atypical vessels in the cochlea than in the vestibular labyrinth. We found a statistically significant positive correlation between vascular variations of the inner ear and concomitant cardiac anomalies or endolymphatic hydrops. We also discuss the possible etiology and potential significance of these findings in terms of disturbances of the function of the inner ear.

Neural hearing loss in a child with poliomyelitis: a histopathological study.

The temporal bones of a 26-month-old white female with a paralytic syndrome clinically and pathologically identical to poliomyelitis were examined. The aetiological agent was unknown although a non-poliomyelitis enterovirus infection seemed likely. There was a complete absence of the cochlear neurons and substantially reduced peripheral and central axons with loss of some inner hair cells but preservation of outer hair cells. Scarpa's ganglion, and the geniculate ganglion were partially atrophied. The saccule and utricle were mildly dilated and Reissner's membrane of the apical turn was bulging. In two previous audiological studies a 10--20 dB bilateral sensorineural hearing loss was found in poliomyelitis patients and a neuronal lesion was postulated which is now supported by our findings. This is a rare example of an almost pure neural hearing loss.

The pathology of the temporal bones of a child with acquired cytomegalovirus infection: studies by light microscopy, immunohistochemistry and polymerase-chain reaction.

STUDY DESIGN: The first case of an acquired cytomegalovirus (CMV) infection of the inner ear is reported in a 3-year-old girl in remission from acute lymphocytic leukemia. METHODS: Horizontal sections of the temporal bones were studied by light microscopy and immunohistological staining by avidin-biotin-complex-technique was performed on selected archival sections. Three sections were processed for detection of the virus genome by the polymerase chain reaction (PCR). RESULTS: By light microscopy the epithelium of the endolymphatic sac, the utricle and the semicircular canals showed deeply stained acidophilic inclusions and the stria vascularis had a loose structure especially in the intermediate layer. The changes were limited to the non-sensory parts of the labyrinth and no CMV type cells were observed in the organ of Corti. There was a loss of inner and outer hair cells and loss of cochlear ganglion cells caused by either the virus or treatment with gentamicin. Standard immunohistochemistry failed to demonstrate staining with CMV antibodies, but PCR, demonstrated CMV-DNA in one section. CONCLUSION: Molecular techniques may be able to detect acquired CMV infections in archival pediatric bones temporal bones. The histologic findings in the labyrinth were milder, however showed some similarity to children with congenital CMV labyrinthitis.

New aspects in the histopathology of the cochlear aqueduct in children.

OBJECTIVE: To study the histoanatomy and pattern of growth of the cochlear aqueduct in children of different ages. BACKGROUND: Since Du Verney described the cochlear aqueduct in 1684, its form, pattern of growth, patency, and function have been controversial. As most of the previous studies of the aqueduct were performed on adults, none had looked at its pattern of growth from the neonate to 9 years of age. In addition, previous histologic studies had suggested an age-dependent patency, but recent investigations had not statistically correlated patency with age. METHOD: Histologic sections of 137 temporal bones from 79 infants and children were studied by light microscopy. From this group, we selected 32 temporal bones from 18 infants, newborn to 9 years (average age 9.1 months, median 0.5 months), in whom the entire length of the cochlear aqueduct was visible on one histologic section. We measured the width of the orifices at the scala tympani (external aperture) and the subarachnoid space (internal aperture) and the length of the aqueduct, and noted the contents of the lumen. RESULTS: The measurements of the cochlear aqueduct were: length 4.19 mm (range 1.7-10.7 mm), width of the external aperture 435 microm (range 225-869 microm), width of the internal aperture 1,323 microm (range 699-2344 microm), mean diameter of the narrowest part (isthmus) 138 microm (range 68-244 microm), intraluminal mononucleated cells 6%, and erythrocytes 15%. CONCLUSIONS: Our findings demonstrate that, in the newborn, the cochlear aqueduct is short and patent. After birth, the duct lengthens significantly primarily by growth of the medial periosteal portion. There was no statistically significant change in the diameter of the external and internal apertures and the isthmus with age. With one exception, the cochlear aqueduct was always present and patent.

Association of adhesive macromolecules with terminal sprouts at the neuromuscular junction after botulinum treatment.

Small quantities of botulinum toxin (BTX) are useful in the treatment of certain movement disorders, such as laryngeal spasmodic dysphonia, blepharospasm, and cervical dystonia. However, the corrective paralytic effects of BTX are only temporary, in part because of the formation of remodeled neuromuscular junctions. Here, we questioned whether various factors within and near the neuromuscular junction could contribute to the remodeling seen after BTX treatment. BTX was injected subcutaneously in the region of the levator auris longus muscle. At 1-week intervals, levator auris longus muscles were removed and examined histochemically. As previously described, BTX treatment results in a progressive elongation of end plates. The neural cell adhesion molecule was not associated with the elongated end plates but was associated with the BTX-induced nerve sprouts after long intervals (3 to 4 weeks). Similarly, after BTX, laminin-1 (composed of alpha 1, beta 1, and gamma 1 chains) reactivity was associated with the nerve sprouts, but not with the end plates. Laminin beta 2 reactivity at the end plate dispersed somewhat within 1 week but remained diffusely associated with the elongating end plates for up to 5 weeks. Together these results suggest that neural cell adhesion molecule and laminins may participate in the sprouting observed after BTX treatment and that alterations in laminin beta 2 expression may participate in initial loss of contacts.

The origin of congenital cholesteatoma.

OBJECTIVE: This study aimed to document histologically the origin of congenital cholesteatoma in neonatal temporal bones. STUDY DESIGN: The study design was a systematic analysis of pediatric temporal bones. SETTING: The study was performed at the temporal bone laboratory, Tufts University School of Medicine and New England Medical Center, Boston, Massachusetts. RESULTS: We describe histologic findings of a congenital cholesteatoma and a squamous epithelial rest in two postpartum patients. In both patients, the masses were asymptomatic and occurred in the anterosuperior quadrant of the middle ear cleft. This is the first histologic documentation of postpartum congenital cholesteatoma. CONCLUSIONS: We believe that these cases represent the first clear histologic documentation of the origin of congenital cholesteatoma.

The cochlear aqueduct in pediatric temporal bones.

The cochlear aqueduct is a bony channel which contains the fibrous periotic duct and connects the perilymphatic space of the basal turn of the cochlea with the subarachnoid space of the posterior cranial cavity. Previous histological studies suggested that patency depended on age, whereas a more recent study showed no statistical correlation between age and patency. To clarify patency in pediatric cochlear aqueducts, we selected 21 temporal bones from 12 infants and children, varying in age from birth to 9 years, in which the cochlear aqueduct was fully visible on one histological section. Photographs were taken for documentation and the length and width of the orifice of the external aperture of the aqueduct at the scala tympani were measured and followed to the internal aperture at the subarachnoid space. The lumen of the duct was examined for mononucleated cells, blood cells and fibrous tissue. Measurements revealed that the mean length of the cochlear aqueduct was 4.6 mm (range, 2.4-10.7 mm), mean width of the external aperture was 484 microm (range, 225-869 microm), and mean width of the internal aperture was 1293 microm (range, 699-2344 microm). The mean diameter of the narrowest part (isthmus) was 151 microm (range, 75-244 microm). In all temporal bones the cochlear aqueduct was patent, with one exception. This latter temporal bone was from a 2-month-old girl with multiple intralabyrinthine anomalies, with the missing cochlear aqueduct believed to be due to an aplasia. Our results support prior measurements of the cochlear aqueduct and demonstrate a short and patent cochlear aqueduct in newborns. With growth, a significant increasing length of the duct was found.

Self-induced pneumoparotitis.

Pneumoparotitis is a rare cause of enlargement of the parotid gland; it is often misdiagnosed and therefore incorrectly treated. We report three pediatric cases of self-induced pneumoparotitis and detail the clinical presentation, pathogenesis, radiographic findings, and treatment options. We also review the literature on the subject. In children, inflammatory swelling of the parotid gland is usually due to acute viral or bacterial infection, juvenile recurrent parotitis, or allergic, autoimmune, or systemic disease. Infrequently, swelling may result from air being forced through Stensen's duct, resulting in pneumoparotitis. This may occur as a transient or recurrent phenomenon. Recurrent parotid insufflation is not entirely benign and may predispose to sialectasias, recurrent parotitis, and even subcutaneous emphysema.

Embryology and anomalies of the external ear.

Malformations of the auricle are not uncommon and occur in 1 out of 12500 births. They can occur alone or can be associated with genetically determined syndromes. Most congenital malformations in the human occur during the third to twelfth weeks of embryonic life. During this period, the external ear is undergoing development and can be affected in many ways. There are three parts to the external ear: the auricle, the cartilaginous external auditory canal, and the bony external canal. The auricle (pinna) and the cartilaginous canal are closely related and probably develop from the same anlage. The bony canal is derived from the tympanic ring which is an incomplete cylinder of membranous bone. It must be clearly understood that, although this article is primarily concerned with the morphogenesis and dysmorphogenesis of the auricle, the rest of the external ear, specifically the external auditory canal, is developing simultaneously. Therefore, maldevelopment of the external canal and the auricle will frequently occur together.

Endolymphatic hydrops in children.

Apart from clinical observations of Ménière's disease in children, there have only been a few histological descriptions of endolymphatic hydrops (EH) as an incidental finding in children. In this paper we report on the incidence of EH in temporal bones of children. One hundred eighteen temporal bones from 70 infants between newborn and 10 years (average age 12.9 months) were analyzed by light microscopy for EH of the cochlear duct, which was defined as a bulging of Reissner's membrane into the scala vestibuli in more than one turn of the cochlea. All endolymph spaces were carefully examined for factors such as an obliterated ductus reuniens which may have contributed to the development of EH. In 64 (54.2%) of the 118 temporal bones, a bulging of Reissner's membrane in the cochlear duct was found. In 65.6%, the bulging was confined to the apical turn and since the significance of isolated apical hydrops is controversial, we elected not to consider this group as having hydrops. Twenty (16.9%) bones met our criteria for a diagnosis of EH. Compared to the high incidence of bulging in the cochlear duct, fewer saccules and utricles were dilated. In approximately half of the temporal bones (49.2%), the ductus reuniens was collapsed. The ductus reuniens seems to be closed in its normal position and might open when pressure occurs due to an increasing volume of endolymph. If there is a permanent closure, EH may result. Our investigation does not indicate that EH is associated with a specific disease; however, where there were congenital anomalies the incidence of EH was higher.(ABSTRACT TRUNCATED AT 250 WORDS)

Non-osteitic complications of therapeutic radiation to the temporal bone.

The temporal bone often falls within the field of radiation for head and neck tumors. Whereas osteoradionecrosis is well recognized as the end-stage complication of radiation to the temporal bone, serious non-osteitic complications can also occur, and these are important because the ear is an organ of special sense. Radiation causes changes in the specialized tissues of the ear that can impair function and influence therapeutic decisions. The purpose of this article is to review the non-osteitic effects of radiation on the ear. A series of cases is presented that illustrate the spectrum of non-osteitic complications of radiation therapy. External canal stenosis, otitis media with effusion, chronic suppurative otitis media with or without cholesteatoma, sensorineural hearing loss, vestibular impairment, and facial nerve paralysis are described. Management should be guided by an understanding of the pathogenesis of these complications. The authors believe that non-osteitic complications of therapeutic radiation to the temporal bone are relatively common and warrant increased recognition.

The utriculo-endolymphatic valve in pediatric temporal bones.

The utriculo-endolymphatic valve (UEV) is located in the posterior wall of the utricle at its junction with the utricular duct and was first described in a human fetus by Bast in 1928. Although different theories about its normal position and function have been postulated, the function of the UEV remains unclear. In the present investigation we studied 118 temporal bones from 70 children to determine whether there were differences in the position of the valve and by inference, its function between children and adults. Premortem ages ranged from newborn to 10 years (mean age, 11.6 months). All temporal bones were fixed in 10% formalin, decalcified and processed by the celloidin technique. Specimens were sectioned in a horizontal plane at a thickness of 20 microns. Every tenth section was stained with hematoxylin-eosin and studied by light microscopy. The position of the UEV was then classified as closed or open. Valves damaged by preparation or having an uncertain position were classified as artifact. The chi-square test was used to determine a correlation between the position of the valve and the status of the rest of the endolymphatic system and whether or not endolymphatic hydrops was present in the cochlear and vestibular systems. The UEV was closed in 39 temporal bones (33.1%) and open in 13 (11.0%). Artifacts were found in 66 bones (55.9%). In the group of patients with a collapsed ductus reuniens the UEV was closed in 38% of the specimens, suggesting that the UEV prevented loss of endolymph from the pars superior, but these findings were not statistically significant.