To date, the rehabilitation of deaf patients with a multichannel cochlear implant has been established as a worldwide accepted method. In case of normal temporal bone anatomy the surgical procedure is standardized and offers few problems. Due to restrictive preoperative patient selection, the incidence of postoperative complications is rather low and is usually flap related.'-5 The percentage of so-called "major complications" which require surgical revision is estimated as low as 7.4%.3 To reduce the surgical risk a sufficient amount of experience in regard to the special type of implant is required. The flap design should be thoroughly planned, the posterior tympanotomy carefully performed and the electrode array gently inserted after an adequate cochleostomy. The importance of a reliable device fixation is emphasized in order to prevent migration.3,6

The PhotoDerm VL is an innovative, highly effective, and comparably safe therapeutic alternative to the laser in the treatment of ETE. The rate of cosmetically relevant side effects is considerably smaller, the patient compliance is excellent, and the method can be applied easily in an outpatient setting.

The proteolytic erosion of the temporal bone is the key event in the pathognomonic course of cholesteatoma progression. The molecular mechanisms of bone resorption, endangering the ossicles, the inner ear, the facial nerve, large vessels or the brain, are not understood. Recently, a new family of proteolytic enzymes, the matrix-metalloproteinases (MMP's) has been described and identified, which seems to play a pivotal role in matrix- and bone homeostasis and inflammatory osteolytic diseases, e.g. osteoarthritis and periodontitis. These enzymes are sophisticatedly controlled by specific inhibitors and activation cascades. We investigated whether human cholesteatoma tissue expresses MMP's and MMP-inhibitors. By immunocytochemistry of cholesteatoma-cryosections, the expression of MMP-2 (72 kD collagenase), MMP-9 (92 kD collagenase), and MMP-3 (stromelysin-1) could be seen to be strictly confined to the basal and suprabasal cell layer of the cholesteatoma epithelium. The neutrophil collagenase (MMP-8) showed a more disseminated expression in the epithelium and the granulation tissue as well. The tissue inhibitor of metalloproteases, TIMP-1, could be detected only in very limited areas of the granulation tissue in a quite randomized manner. Therefore, a derailment in favor of proteolysis of the normally tightly controlled MMP-system might be postulated. The results indicate that members of the MMP-family could play an active role in the molecular mechanisms of cholesteatoma invasion into the temporal bone. This offers new insights into the pathophysiology of the disease and of potential therapeutic approaches.

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