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.

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.

[Practical recommendations concerning the use of aluminum oxide implants in middle ear surgery (author's transl)]. / Praktische Hinweise zur Anwendung von Mittelohr-Implantaten aus Aluminiumoxid-Keramik.

Our experiences with the implantation of bionert aluminum oxide ceramic middle ear prostheses are described. We have found that each implant must be shaped to fit exactly the specific defect encountered in the middle ear. Recommendations for shaping and inserting the implants are detailed.