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Abstract
Pagef’s disease (osteitis deformans) is a common condition affecting particularly the skull, pelvis, vertebral column and femur in people over 40 years of age. The cause is not yet certain, but the presence in many cases of paramyxovirus-like structures seen within osteoclasts has prompted the suggestion that Pagefs disease may be of viral aetiology and the measles virus and canine distemper viruses have been under scrutiny as candidates. The pathological change is one of active bone formation proceeding alongside active bone destruction. The affected bones are enlarged, porous and deformed. Microscopically, bone formation is seen in trabeculae of bone with a lining of numerous osteoblasts. A mosaic appearance is formed by the frequent successive deposition of bone, cessation of deposition resulting in thin, blue “cement lines”, followed again by resumption of deposition and its cessation, and so production of further cement lines. Bone destruction is shown by the presence of numerous, large osteoclastic giant cells with Howship’s lacunae. Areas of chronic inflammatory exudate intermixed with the bone are common (Fig. 10.1).
Malleus head fixation is a rare but not exceptional pathology. It may be apparently congenital or acquired, and can be associated with stapes fixation. In the acquired secondary process two histological types of malleus head fixation were found: the first corresponded to non-tympanosclerotic bone remodeling and the second to localized tympanosclerosis.
To describe the histopathologic features of malleus head fixation and to correlate them with its clinical appearance.
Ten patients with surgically proven malleus head fixation were included in this series. A fixed malleus head was resected via a transcanal approach in six patients, and attic bony fragments fixing the malleus head were removed via a mastoidectomy without disruption of the ossicular chain in four. Histopathologic studies were performed for both types of malleus head fixation.
Three types of acquired malleus head fixation were defined in accordance with the surgical and histopathological findings. Histologically, the first type presented with normal bone tissue, the second was characterized by non-tympanosclerotic bone remodeling and the third presented with a localized tympanosclerotic focus in the tympanic cavity.
Osteitis deformans Paget is a fairly common, heritable, sometimes progressive disease of bone which affects primarily the axial skeleton and may lead to deformity and weakness. It affects 3% of the population over forty years of age and males more frequently than females. The skull and temporal bones become involved in about two-thirds of the patients. Progressive involvement of the temporal bones may lead to alteration of position, increase in size and change of architecture of the petrous pyramid, external canal, middle ear and inner ear capsule. These changes in turn may produce impairment of hearing (about 30–50% of cases) and vestibular function (20–25%). The clinical, radiological, and pathological manifestations of Paget's disease of the temporal bone are discussed in detail and explained with photomicrographs. Examples of tumor formations and vascular changes are presented.
OSTEOPETROSIS,also known as Albers-Schonberg disease, osteosclerosis, marble bones, and chalk bones, is a rare hereditary congenital and familial abnormality in bone development. The abnormality appears to be a failure of resorption of calcified cartilage and primitive bone.1 This necessarily interferes with the formation of the adult bone which normally replaces it.
The abnormal bone development and the accompanying alterations in physiology give rise to a number of interesting clinical features. Radiographically there is a striking opacity of the bones and obliteration of the medullary cavity. The bones are hard since they contain large quantities of calcium salts but brittle since there is no organization of the unresorbed primitive bone to resist stress. The long bones break like chalk, transverse to their long axis2 (Fig 1). A patient may have multiple fractures which heal producing a callus which has the same abnormal features as the original bone (Fig 2).
Osteitis deformans Paget is a fairly common, heritable, sometimes progressive disease of bone which affects primarily the axial skeleton and may lead to deformity and weakness. It affects 3% of the population over forty years of age and males more frequently than females. The skull and temporal bones become involved in about two-thirds of the patients. Progressive involvement of the temporal bones may lead to alteration of position, increase in size and change of architecture of the petrous pyramid, external canal, middle ear and inner ear capsule. These changes in turn may produce impairment of hearing (about 30-50% of cases) and vestibular function (20-25%). The clinical, radiological, and pathological manifestations of Paget's disease of the temporal bone are discussed in detail and explained with photomicrographs. Examples of tumor formations and vascular changes are presented.
We present the pathologic features in the temporal bones of a 62-year-old woman with the adult benign form of osteopetrosis. Most of the bony tissue was expanded by dense lamellar bone, with, in some places, the presence of residual calcified cartilage. In the otic capsule, globuli interossei were greatly increased in number. The ossicles were enlarged with fixation of the stapes. Narrowing of mastoid air cells, the internal auditory meati, and eustachian tubes was present, the latter associated with chronic otitis media. The bone deposition in the ossicles contributed to the conductive hearing loss, which was a prominent feature in this patient's otologic findings. The narrowing of the internal auditory meati may similarly have contributed to a degree of sensorineural hearing loss.
In an attempt to better define the changes affecting the temporal bone that might predispose achondroplastic dwarfs to otitis media, nine achondroplastic subjects who were evaluated for hearing loss underwent high-resolution CT scanning of the temporal bone. Comparisons were made with 10 nonachondroplastic subjects. A number of morphologic changes were seen, including (1) poor development of mastoid air cells, (2) foreshortening of the carotid canals, (3) narrowing of the skull base, (4) "towering" petrous ridges, and (5) relative "rotation" of the cochlea and other temporal bone structures. The most significant change was the rotational effect, which was more pronounced medially, resulting in an abnormal orientation of inner ear structures relative to middle ear structures and of middle ear structures relative to the external auditory canal. There was a notable lack of evidence for otitis media or its sequelae in any of the achondroplastic subjects. Audiograms were obtained in six of the nine achondroplastic subjects (two adults and four children). There was evidence of mixed hearing loss in the four children, but only of sensorineural hearing loss in the adults. We believe that the persistent hearing loss in achondroplasia is not due to sequelae of otitis media as some authors have suggested. Intrinsic vestibulocochlear changes below the limits of resolution of high-resolution CT scanning may be responsible.
O TOSCLEROSIS generally occurs as a localized bone disease in which the morphological changes are presumably limited to the otic capsule. In the majority of instances, the pathological process develops in front of the oval window in the immediate vicinity of the window margin. As the lesion expands, the window margin becomes progressively involved. Involvement of the frame of the vestibular fenestra may lead to distortion of the window architecture or to ankylosis of the stapes footplate or to both. Stapes fixation in turn causes interference with sound conduction to the inner ear. Since otosclerosis frequently involves the otic capsule and in a certain percentage leads to stapes fixation, it constitutes a common etiology for impairment of hearing in adults. Although available figures do not indicate the exact incidence of the disease, there is good evidence that, at the present time, otosclerosis accounts for the hearing loss in nearly one
The simultaneous ocurrence of otosclerosis and otospongiosis in the same lesion is well documented. The logical sequence of events would seem to be softening and destruction of the bone by the otospongiotic lesion, which is subsequently converted to otosclerosis. Examination of 46 temporal bones had led us to further classify the lession as: 1. an active lession, both otospongiotic and otosclerotic, 2. an inactive lesion, also both otosclerotic and otospongiotic, or 3. a fibrous lession.
Hyalinization of the spiral ligament only occure adjacent to active otospongiotic or very large otosclerotic lesions. If the lesion adjacnet to the spiral ligament is inactive, there is no hyalinization. It seems illogical that a hyalinized spiral ligament will return to normal when the lesion changes from active otospongiosis to inactive otosclerosis.
Otospongiotic and otosclerotic lesions are found side by side at the periphery of lesions, and both are adjacent to normal bone. These findings have implications concerning the mode of action of sodium fluoride and other medications that are under evaluation for the control of the sensorineural hearing loss due to otosclerosis.
Extensive research into the inmost mechanism of otospongiotic disease and an extended study of otosclerotic patients' ancestry have led the authors to a plan for prevention of this disease, which appears to be a genetic deafness with autosomal dominant inheritance and about 40 percent penetrance of genes. Progress in impedance audiometry has permitted early detection of stapedial fixation by means of systematic audiometric investigations, particularly the elicitation of stapedius reflex showing a very special pattern called the "on-off effect." The evidence supporting an enzymatic origin of the sensoringeural component of hearing loss in otosclerotic families has led us to treat otospongiotic children with very low doses of sodium fluoride, with no risk of stunting growt. We have been applying this procedure for four years to the families of stapedectomized otosclerotic patients. We believe it would be advisable to extend this type of prevention to schoolchildren by means of systematic audiometric investigations, including the elicitation of stapedius reflex to detect a possible on-off effect. We also studied sodium fluoride therapy, which derives from the enzymatic origin of the otospongiotic disease. This treatment, based on enzymogenesis inhibitors, should be given to young otospongiotic/otosclerotic patients detected by systematic audiometric investigations. Sodium fluoride could even be prescribed for otospongiotic mothers to prevent disease in their newborn children, exactly as in dental prevention. Otospongiotic/otosclerotic disease can be easily controlled by medical treatment, combined with surgery if needed. This treatment is effective thanks to early detection.
This temporal bone report describes the inner ear deformities which were found in addition to the bony pathology in a case of osteogenesis imperfecta congenita. The labyrinthine pathology includes anomalously positioned and enlarged vestibular spaces, the existence of a scala communis (on one side) and the existence of hematoxylin dark-stained material in the basal zone of the stria vascularis.
The appearance of temporal bone reports of osteogenesis imperfecta congenita is sporadic. Friedmann (1974)described changes in the bony capsule in one case of osteogenesis imperfecta congenita Zajtchul and Lindsay(1975)reported three cases of the congenital form of osteogenesis imperfecta with their temporal bone findings. Within recent years, Altmann reported three cases in 1962, Bretlau and Jorgensen reported one case in 1969, Bergstrom and others reported one case in 1972, and Bergstrom described the temporal bone findings in four infants in 1977. The pathologic description of the temporal bone in osteogenesis imperfecta congenita has been focused more or less on the structures of the bony labyrinth and the middle ear ossicles, with a brief description of the inner ear. In this report, we describe anomalous inner ear structures in osteogenesis imperfecta congenita.
Investigation of a possible viral etiology for otosclerosis was initiated because of the clinical and histopathologic similarities between otosclerosis and Paget's disease of bone and the mounting evidence of a viral etiology in Paget's disease. Thus far, ultrastructural and immunohistochemical studies have revealed measles-like structures and antigens in active otosclerotic lesions. A method for isolation and identification of both DNA and RNA sequences in archival human temporal bone specimens using the polymerase chain reaction technique has been developed. With use of this technique, a 115-base pair sequence of the measles nucleocapsid gene has been identified in 8 of 11 different temporal bone specimens with histologic evidence of otosclerosis. Zero of nine control specimens without histologic evidence of otosclerosis were positive. The association between the presence of the measles nucleocapsid gene sequence and histologic otosclerosis was significant (p < 0.01). This study provides further evidence for a possible measles virus etiology in otosclerosis.
Osteogenesis imperfecta (OI), or the Van der Hoeve-de Kleyn syndrome, is a heterogeneous group of connective tissue disorders. The key features in this disease are bone fragility with a tendency to spontaneous fractures and deformations. The classical traid of symptoms involves a conductive and/or sensorineural hearing impairment together with a tendency to spontaneous bone fractures and blue sclerae. Between January 1988 and December 1994, ear surgery was performed on eight ears of six OI patients who presented with mixed hearing loss preoperatively. Pathological changes observed in the middle ear were atrophy and/or fractures of the stapedial crura in combination with thickening and fixation of the stapes footplate. Partial stapedectomy was performed in seven cases and a neo-window was created in the promontory of one patient when an overhanging facial canal obscured visualization of the oval window niche. Pre- and postoperative bone conduction thresholds did not differ in any of the patients. Postoperatively, mean values of the air-bone gap in the main speech frequency range were below 10 dB. Functional results following stapes surgery in patients with otosclerosis during the same time interval (n = 857) did not differ significantly. These data indicate that stapes surgery in OI patients can be performed with the same functional predictability as in otosclerosis patients, even though the underlying etiology is considerably different.
Otosclerosis is related to mild osteogenesis imperfecta with genetic defects in type I collagen.
Otosclerosis is a common bone disease of the human otic capsule that has an underlying hereditary predisposition. The histopathology and clinical manifestations are strikingly similar to the milder forms of osteogenesis imperfecta in which mutations of type I collagen genes have been established as the underlying cause.
The authors investigated the genetic basis of otosclerosis by conducting an association study using polymorphic DNA markers from patients with clinical otosclerosis and random control subjects.
This study showed a significant association between clinical otosclerosis and the type I collagen COL1A1 gene using three different polymorphic markers within the gene.
Some cases of clinical otosclerosis may be related to mutations within the COL1A1 gene that are similar to those found in mild forms of osteogenesis imperfecta and result in null expression of the mutant allele.
Histologic otosclerosis is a disease process without clinical symptoms or manifestations that can be discovered only by sectioning of the temporal bone at autopsy. Clinical otosclerosis is otosclerosis at a site where it causes conductive hearing loss by interfering with the motion of the stapes or of the round window membrane. Various authors have studied the prevalence of histologic otosclerosis on laboratory collections of temporal bones. Some 12% to 15% of temporal bones with histologic otosclerosis have demonstrated stapedial fixation. Using these figures for calculating the prevalence of clinical otosclerosis gives an extrapolated clinical prevalence of 0.99% to 1.2%. This does not correlate well with the clinical data on otosclerotic families, from which a clinical prevalence of 0.3% has been estimated.
To study the prevalence of histologic otosclerosis in an unselected series of temporal bones.
During a 1-year period, 118 consecutive pairs of temporal bones of deceased patients at a tertiary care center were collected to determine the prevalence of otosclerosis. Although histology remains the gold standard for evaluation of otosclerosis, the gross observation of temporal bone slices combined with microradiography was used to screen for otosclerotic lesions more rapidly and with a lower cost/benefit ratio. The temporal bones, which were suspected of having otosclerosis with these techniques, were further analyzed by conventional histology.
2.5% of the 236 temporal bones (or 3.4% of patients) studied demonstrated histologic otosclerosis.
Although the prevalence of 2.5% is much lower than previously published figures on histologic otosclerosis, the extrapolated data (extrapolated clinical prevalence = 0.30% to 0.38%) correlate well with clinical studies of otosclerotic families. The previous studies based on laboratory collections were likely biased by hearing loss or other otologic diseases.
CT of the temporal bone in achondroplasia
- S R Cobb
- M Shohat
- C M Mehringer
- SR Cobb
Association of C0L1A1 and otosclerosis: evidence for a shared genetic etiology with mild osteogenesis imperfecta
- M J Mckenna
- A G Kristiansen
- M L Bartley
- MJ McKenna