[Cold deformation elements for attaching an implantable hearing aid transducer to ear ossicles or perilymph]. / Kaltfliessende Elemente zur Ankopplung eines implantierbaren Hörgerätewandlers an Gehörknöchelchen oder Perilymphe.

Development and short-term implantation results of the Tübingen implantable hearing aid (TI = Tübingen implant) have been presented. The TI is designed for patients with sensorineural hearing loss due to a malfunction of the cochlear amplifier. This can be identified by the presence of positive recruitment and the absence of TEOAE (transitory evoked otoacoustic emissions). The Tübingen implant functions in two ways: it allows electronic amplification of the auditory signal and electromechanical signal transduction into a micromechanical vibratory stimulus. There are two paths by which vibratory stimulus reaches the cochlea: (1) directly through a perforation in the stapes foot plate into the perilymph or (2) via the ossicular chain. Made of pure titanium, the casing of the helium-tight welded transducer includes the piezoelectric actuator. An implantable manipulator device is designed for transducer positioning and anchoring in the mastoid cavity. Usually, the transducer probe tip is directly coupled to the body of the incus. This functions without a special coupling device by utilization of an Erbium-YAG laser. Special anatomical situations or the loss of incus and/or stapes suprastructure, however, requires coupling of the vibratory signal to other points of the ossicular chain or to the perilymph. A major problem, however, was an intraoperative, irreversible link between the titanium probe tip and coupling elements. To overcome this problem, the coupling elements were made of gold. A crimp technique was developed, allowing the surgeon to induce cold deformation of the gold. The cold deformation technique (crimp) results in an irreversible coupling between the titanium probe tip and the golden coupling element.

[Ossicular coupling of an implantable hearing aid transducer using an Er:YAG laser]. / Ossikelankopplung eines implantierbaren Hörgertewandlers mittels eines Er:YAG-Lasers.

Special coupling devices made of pure gold or titanium have been developed to connect a new implantable hearing aid transducer (Tübingen implant) to the ossicular chain. They allow piezotransducer probe-tip connection to the long process of the incus or the stapedial head. Similar to the design of conventional PORPs (partial ossicular replacement prostheses), the coupling devices can be fixed at the ossicular chain, e.g., with the eye loop of stapedial piston prostheses or the bell element of golden wire PORPs. A crimp technique allows connection between coupling device and transducer probe tip [5]. The main disadvantage in connecting the long process of the incus or the stapes having is to drill a dorsal tympanotomy in the posterior wall of the ear canal during surgery. The short distance between tympanotomy and N. facialis contains serious surgical risks. To avoid the risk of facial paralysis, Fredrickson's alternative coupling technique for the body of the incus is investigated in this paper [2]. In this case, the transducer probe tip will be positioned to the incus body and placed on its surface with controlled elastic displacement of the ossicular chain. The simple direct attachment of the probe-tip end on the surface of the incus, however, will not guarantee a stable long-term connection. Thus, by creating a conical, 0.5-to 0.7-mm-deep hole in the incus, the probe tip will be fitted much better. With a novel surgical Erbium-YAG laser this can be done in a contactless procedure. In this paper, first results of microsurgical laser applications with human temporal bones will be shown.

[Surgery for deafness: tympanoplasty]. / Chirurgie de la surdité: les tympanoplasties.

The communicative task of the auditory system is characterized by the perception of sound in it's complexity. This holds true especially for verbal communication which is the most important part of the condition human of man. Based on these thoughts the development of otosurgery up to tympanoplasty is highlighted.

High antibody levels against mouse laminin with specificity for galactosyl-(alpha 1-3)galactose in patients with inner ear diseases.

Sera of 413 patients with inner ear diseases were examined for ELISA binding to mouse laminin and compared to a normal group. Strongly enhanced antilaminin antibody reactions were observed in a large number of patients with sensorineural hearing loss (68%), tinnitus (60%), and sudden deafness (46%), but not in those with Meniere's disease (14%) or normal individuals (8%). Absorption experiments demonstrated that these antibodies are also responsible for the antisarcolemmal antibody pattern in the immunofluorescence test and for the reaction with pig kidney microsomes in the ELISA. Immunochemical studies showed that laminin binding of high or low titer in sera from patients and normal individuals is due to the Gal alpha 1-3Gal epitope present in N-linked oligosaccharides of mouse laminin. No reactions were observed with human laminin, which lacks this epitope. The findings suggest that high levels of antibodies against carbohydrate structures are triggered by persistent infections, providing some new insights about the possible cause of these diseases.

Autoimmune hearing loss.

Tissue nonspecific antibodies may give an idea about the etiopathogenesis of the inner ear disease. They are of some prognostic and therapeutic value. They are routinely tested in most inner ear patients. On the other hand, inner ear specific autoantibodies do exist. Their diagnostic, prognostic and therapeutic significance are still unclear. Cellular immunity is tested only in selected cases based upon the clinical picture and the results of humoral immunity testing. It needs whole fresh blood as well as facilities not available in all laboratories. Their main role seems to be in providing solid basis for cortisone therapy justification. Our therapeutic concept proved to be promising in some cases. Immune-mediated inner ear disorders do not form a separate clinical entity. We would rather add immune mediation to the different causes postulated for the various inner ear disorders, as a plausible explanation for a certain percentage of the group categorized as idiopathic of unknown etiology.

Anti-laminin antibodies in inner ear diseases: a potential marker for infectious and post-infectious processes.

Natural antibodies against laminin (ALA) have been detected recently in some acute and chronic infectious disorders. In our present study sera of a large number of patients with inner ear disorders of unknown etiology (n = 413) were tested for ALA. Control sera were taken from patients with diseases of known infectious etiology and patients with diseases of unknown etiology in which an infectious etiology was suggested. Patients with classical autoimmune diseases as well as healthy blood donors were also included in this study. The highest frequency of ALA was found in patients with sensorineural hearing loss (SNHL) (68%), whereas the incidence of ALA was comparatively uncommon in patients with Menière's disease (14%). In patients with chronic infectious diseases ALA were detected with almost the same frequency as in patients with SNHL. The elevation of the erythrocyte sedimentation rate and the association of ALA-positive SNHL with other chronic inflammatory disorders suggest that ALA might be stimulated by a persisting infectious process. These findings suggest that certain forms of inner ear disorders might have a chronic infectious etiology.

[The "old radical" surgery. History and development of surgery of the mastoid]. / Die "alte Radikale". Geschichte und Entwicklung der Chirurgie des Warzenfortsatzes.

After a brief historical outline of the radical operation of the ear, the possibilities are presented which are at our disposal to construct a mastoid cavity after removal of the posterior bony wall of the auditory canal, thus keeping the problems for the patient at a minimum. At best, a small self-cleansing well-designed cavity is formed under favourable conditions. Important prerequisites for the construction of such a cavity are: A good overview obtained by smoothening of the cavity walls; widening of the auditory canal entrance (cartilage excision); removal of excess bone covering the facial nerve; and reducing the size of the cavity by means of a Palva flap while preserving the postauricular artery and its larger branches. Postoperative management (and cleansing) must be done with an operation microscope.

[When should an ear not be operated on]. / Wann man ein Ohr nicht operieren sollte.

Despite the low morbidity of modern middle ear surgery there are some limitations in indication. The age of the patient, the function of the Eustachian tube, the fibrotic middle ear, the cleft palate, the glomus tumour, Menière's disease and "the last hearing ear" of the patient are discussed as far as middle ear surgery is concerned.

Experiences with Al2O3--ceramic middle ear implants.

The excellent tolerance of bio-inert aluminium oxide ceramic after being implanted into the middle ear has been shown by our electron microscopic studies and clinical experience over 4 years. Our implants developed for ossicular chain reconstruction were covered by a delicate middle ear mucosa within a few weeks. We have observed no foreign body reactions. The ceramic implants are distinguished by the almost unlimited number of forms or shapes into which they can be ground quickly and precisely during operation. We value Al2O3 ceramic implants because there is no bony fixation with the surrounding bone but rather a joint-like connection with the remaining parts of the ossicular chain.

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.

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.