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Biomedical subjects

D Plester

Publications and source records attributed to D Plester.

At least 37 records · Page 2Linked to original sources
PubMed1981

Idiopathic malleus head fixation as a cause of a combined conductive and sensorineural hearing loss.

Osseous fixation of the malleus is discussed as a cause of combined conductive and sensorineural hearing loss. The characteristic clinical, audiological and histological findings, as well as the aetiology of 66 patients with an idiopathic fixation of the head of the malleus is described. Ninety-four per cent of these patients had a sensorineural component to their hearing loss far greater than the loss that could be attributed to presbyacusis. Idiopathic fixation of the head of the malleus was the second most common of the fixed malleus syndrome in the series of 168 ears operated on in the Ear Nose and Throat Department of the University of Tübingen between 1972 and 1977. The treatment of choice is to keep the ossicular chain intact. Reconstruction of the disrupted chain is preferred in patients with poorly pneumatized mastoids. Only 15% of the patients with idiopathic fixation showed a significant improvement in their bone-conduction after surgery.

Adult↗
PubMed1981

The anterior tympanomeatal angle: the aetiology, surgery and avoidance of blunting and annular cholesteatoma.

Forty-eight cases of anterior annular cholesteatoma were treated surgically. All these cholesteatomas had occurred following surgical repair of the tympanic membrane by the onlay method. To confirm the likely aetiological causes, 49 specimens of the anterior annular sulcus were studied histologically. It was found that in 31% of specimens there was a fold of epithelium penetrating deep into the subepithelial tissue. In 6 specimens there were epithelial cones present and in 9 specimens excessive subepithelial fibrous tissue was noted. The complication of "blunting" caused by the onlay technique is almost impossible to avoid. A more dangerous complication is annular cholesteatoma. The surgery of blunting and annular cholesteatoma and the principles of the underlay method of grafting are described.

Cholesteatoma↗
PubMed1981

Tullio phenomenon with torsion of the eyes and subjective tilt of the visual surround.

A 44-year-old male patient had an acoustic trauma three years previously, after which he suffered from vertigo and tilting of the environment to the right when uttering the vowels u or e. At such times, a tonic eye torsion to the left, which lasted throughout the utterance, was observed under Frenzel's glasses along with head tilt to the left. The phenomenon could be elicited experimentally by right-ear stimulation with low-frequency noise (mean frequency, 125 Hz; 90 dB), as well as by constant pressure. The patient also reported observing the phenomenon with loud noises, nose blowing, obstruction of his right external meatus with the finger, and with altitude pressure changes in a car. This suggests that the phenomenon is elicited via the eardrum and the ossicular chain. Since lateral head tilt and counterrolling were tonic and without nystagmus, it is unlikely that one of the semicircular canals is involved as in usual Tullio cases. Rather, the otoliths may play a role in pathogenesis. Possible causative mechanisms are discussed along with the relevant literature.

Acoustic Stimulation↗
PubMed1981

Ceramic implants in otologic surgery.

We have examined the suitability of ceramic materials for reconstruction in middle ear surgery. The excellent tolerance of bio-inert aluminum oxide ceramic implanted into the middle ear has been shown by our electron microscopic studies and clinical experience. Our implants developed for ossicular chain reconstruction were covered by a delicate middle ear mucous membrane within a few weeks. We have observed no foreign body reactions. The ceramic prostheses are distinguished by the almost unlimited number of forms or shapes into which they can be ground quickly and precisely during the operation. We value Al2O3 ceramic implants because there is no bony fixation with the surrounding bone, but rather a jointlike connection with the remaining parts of the ossicular chain. The composition of resorbable tricalcium phosphate, bio-active ceramic, corresponds to the inorganic component of bone. Because it exhibits the characteristic of being replaced by autogenous bone, we consider it for the obliteration of mastoid cavities. Based on our preliminary experience, dense tricalcium phosphate ceramic might play a valuable role in the reconstruction of the posterior auditory canal wall. In addition, we have used dense tricalcium phosphate ceramic to correct minor ossicular chain defects (for example, erosion of the long process of the incus). A survey is given concerning the indications and techniques for the use of these new materials in middle ear surgery, as well as our results covering a period of three years, which are very encouraging as far compatibility and function are concerned.

Aluminum Oxide↗
PubMed1980

Middle ear tuberculosis.

Fourteen cases of tuberculous otitis media are reported. With the declining incidence of pulmonary tuberculosis, the number of reported cases of tuberculous otitis media has become scanty. Nowadays the so-called classical signs of the lesion such as a profuse discharge, profound hearing loss, facial paralysis and multiple perforations, are hardly ever seen. Surgical intervention when done under cover of anti-tubercular drugs has no deleterious effect on the result of surgery. In order not to miss tuberculous otitis media, whenever the otologist is dealing with chronic middle ear disease, the following points should always be kept in mind: (a) A dull ache in the ear without obvious inflammatory signs. (b) A whitish-grey appearance of the mucosa. (c) Bulging of granulation tissue from the mastoid cells during surgery.

Adolescent↗
PubMed1980

Basilar impression. A differential diagnosis of Menier'es disease.

We examined the craniocervical region in 180 patients with nonspecific dizziness and unilateral sensorineural hearing loss in most of them. In 32 cases, we found malformations of the craniocervical region. The symptoms of the basilar impression are probably caused by compression of the vessels of the lower cerebellar region and the brainstem as well as by disturbances of the CSF circulation. The diagnosis of basilar impression is based on lateral x-ray films of the skull base, tomography of this region, and in some cases on computerized axial tomography. We emphasize the importance of basilar impression in the differential diagnosis of Meniere's disease.

Diagnosis, Differential↗
PubMed1980

[Ceramic implants in middle ear surgery (author's transl)].

Several different ceramic materials have recently been used in middle ear surgery: bio-inert aluminum oxide, bio-active glass and bio-active tri- and tetra-calcium phosphate. We have compared these materials with regard to their physical properties as well as various characteristic biological reactions when used in implantation. All of these materials were found to exhibit excellent biocompatibility. Other advantages relate to specific applications of the material and depend on the particular qualities of the individual ceramic. However, we conclude that caution is needed against the uncritical application of these materials in middle ear surgery and consider some still open question for their use.

Animals↗
PubMed1980

Hereditary factors in chronic otitis with cholesteatoma.

Hereditary or genetic factors influence the degree of pneumatisation as demonstrated by Schwarz, Dahlberg and Diamant. The angulation at the base of the skull interferes with the anatomical position and patency of the Eustachian tube and leads to impaired pneumatisation of the mastoid. In patients with primary acquired cholesteatoma the angle formed by the clivus, posterior clinoid process and posterior border of the hard palate is significantly smaller than in non-cholesteatomatous patients. The configuration of the epipharyngeal region is considerably different in cholesteatoma carriers than in normal individuals. In cholesteatoma carriers the epipharyngeal lumen is significantly smaller than in normal individuals.

Cholesteatoma↗
PubMed1978

[Unilateral deafness (author's transl)].

Unilateral conductive deafness has a readily determined aetiology in most cases. In contrast, unilateral sensorineural hearing loss requires more refined and extensive investigation. The most frequent causes of unilateral sensorineural hearing loss in our patients were sudden deafness, Menière's disease, cranio-vertebral dysplasia and cerebellopontine angle tumors. Early diagnosis of acoustic neuroma or other lesions of the internal auditory meatus or cerebellopontine angle requires special attention. The definitive diagnosis of these tumors often demands intensive clinical investigation but a high degree of suspicion may be entertained following modern routine audiometry, vestibular function testing and radiological examination. The importance of early diagnosis of these lesions is stressed with regard to the mortality rate for larger tumors and to the preservation of facial nerve function. The reliability of different diagnostic investigations is documented.

Brain Diseases↗
PubMed1977

[Active otosclerosis of the stapes footplate: histological and clinical aspects of its influence on the perilymph (author's transl)].

Pathologic capillaries are usually seen in the center of an otospongious process. Next to obliteration, dilatation and increased permeability a loss of basement membrane structure is evident. Around the capillaries exists a wide network of mesenchymal cells which have a glycogen like mass within the cytoplasm; glycogen can be delivered into the extracellular fluidspace. Free erythrocytes are located around many vessels. Near the margin of the lacunae decalcificated areas are seen; in the center of these areas osteocytes undergo lysis; they show intracytoplasmatic deposits of apatite which we assume to be located within the mitochondria. The collagen structure in the neighbourhood of the osteocytes seems to be damaged. Once the resorptive process has reached the perilymphatic surface of the footplate there comes to an connection between the otospongiotic lacunae and the vestibule. Free erythrocytes, glycogen like drops and lysosomes are delivered into the perilymph. Comparing the histological results with the operative results in patients with floride otosclerosis we conclude that operation should be done as early as possible to prevent damage from the inner ear, caused by the continuous intoxication of the perilymph from the otosclerotic focus.

Bone Resorption↗
PubMed1977

Histologic fate of tympanic membrane and ossicle homografts.

1. The biologic behavior and usefulness of homologous incus grafts preserved in Cialit compare favorably with that of ossicular autografts. 2. Reconstruction of the transplanted incus correlates with the period of its immersion in preservative: the briefer the period of exposure to fixative, the more rapidly resorption and substitution occur. The longer the preservation time, the slower the rate of incus transplant reconstruction. 3. The preserved heterograft bone chip is unsuitable, since it disintegrates completely irrespective of the duration of its preservation. 4. The configuration of all bone chips is extensively altered after implantation. Autograft and homograft bone chips are both poorly tolerated. Chemical fixation does not alter this reaction. Fragments are shortened, softened, and rounded off. Heterologous bone chips are completely resorbed.

Animals↗
PubMed1975

[Vascular degeneration in otosclerosis and its influence on the mesenchymal reaction of the mucoperiost].

38 samples of middle ear mucosa were taken from different patients during stapes surgery in otosclerosis. The samples were studied light-and electronmicroscopically without decalcification. Considerable pathologic changes in the organisation of the capillaries (endothelial hydrops, proliferation of the intima and of the adventitia, total obliteration o the vessels) cause pathologic reactions on the mesenchymal elements of the submucosa. Next to fibrolysis or hyalinosis of the collagen fibers the fibrocyts show features of undergoing lysis. Free and cellular bound calcium deposits are located in these lytic areas. The epithelial lining also shows unusual inclusions as glycogen and acid mucopolysaccharides and an alterated basement membrane. We belive that the changes of the connective tissue and of the epithelium are secundary to the capillary obstruction.

Apatites↗
PubMed1975

[Homologous transplants in the middle ear (author's transl)].

The original concept of tympanoplasty included besides the closure of the middle ear, the removal of pathological middle ear components leaving intact the functional and healthy components. The special conditions that prevail in the middle ear (aeration, absence of intrinsic trauma) allow the reconstruction of the middle ear mechanics to a great extent. Animal experiments and clinical experience reveal good transplantation properties of denatured and preserved ear ossicles. They are partly replaced by the body's own true tissue, and preserve the original form over a period of years. Denatured dear drums with malleus, incus, and parts of the stapes give astounding acoustic results. The posterior bony canal wall in old radical cavities can be replaced by the posterior wall of the human temporal bone which has been preserved in Cialit.

Bone Transplantation↗