Reconstruction of the ossicular chain with titanium implants.

OBJECTIVES: Since 1994 more than 1300 titanium implants have been used to reconstruct the ossicular chain of the middle ear for chronic otitis media. Two different types of implants were used. First, a total and a partial implant of fixed length, available in numerous different lengths. And second, a total and partial implant that has an adjustable length. The implants are commercially available from 2 different companies. Patients were followed for a postoperative term from 6 to 72 months. METHODS: A wide variety of patients aged 5 to 82 years received a tympanoplasty type III. Those patients whose ossicular chain had been reconstructed with titanium implants since 1994 were evaluated. As implants from one company are fixed in length; implants of a second company are trimmable in length. All prostheses are lightweight and made of pure titanium, fitting most anatomical situations. RESULTS: Earlier results already showed a very low complication rate. Extrusions occurred only in cases of middle ear atalectasis with resorption of interposed cartilage (<1%). No adverse reaction to the prostheses could be seen, even in histologic reviews. An average air-bone gap less than 20 dB(A) for all calculated frequencies of 0.5, 1, 2, and 4 kHz was achieved for 76% of cases; 43% of cases showed a calculated air-bone gap of less than 10 dB(A), only 10% higher than 30 dB(A). CONCLUSION: All implants used offer the proven benefits of titanium, namely high biocompatibility and high stability at a very low complication rate with excellent hearing results for the patients. Titanium implants can highly be recommended to reconstruct the ossicular chain of the middle ear.

[Three years of experience with titanium implants in the middle ear]. / Titan-Prothesen im Mittelohr. 3-Jahres-Erfahrungsbericht.

BACKGROUND: In continuation of our previously published report on initial experience with titanium implants in the middle ear [13], we now present the results of routine use over a three year period. METHODS: From November 1994 to November 1997, 661 titanium implants (Düsseldorf model) were implanted in the authors' clinics (355 PORP, 306 TORP). There was no preselection of patients. Five hundred eighty-two follow up examinations were performed with a medium follow up time of 11.6 months. RESULTS: The good initial results of the previous study with respect to biocompatibility and functional hearing results were confirmed in the long term follow-up. The average air-bone gap was calculated over the frequencies 0.5, 1, 2, and 4 kHz. Closure to within 20 dB was achieved in 72% of cases. The air-bone gap tended to decrease with increasing time of implantation. Adverse reaction to the prostheses did not occur. Extrusion occurred in one case of complete middle ear atelectasis with resorption of the interposed cartilage. Insufficient improvement of hearing was attributable to a short implant in 12 cases (1.8%). In three cases (0.5%) insufficient stability of the PORP was attributable to eroded stapes suprastructure, and in three others (0.5%) a dislocation was responsible for a poor hearing result. Middle ear fibrosis with impairment of sound transmission was seen in 3 patients (0.5%). CONCLUSION: The superior acoustic properties of the delicate yet rigid low-weight titanium implants combined with excellent biocompatibility lead to a good hearing result if a meticulous surgical technique is employed. The easy handling makes it a pleasure to work with these protheses.

[Replacement of ear ossicles with titanium prostheses]. / Gehörknöchelchenersatz mit Titan-Prothesen.

BACKGROUND: Titanium has been a well established implant material for many years. New material processing techniques now permit the manufacture of small implants for ossicular chain reconstruction. METHODS: Between November 1994 and September 1995, 100 titanium middle ear implants (55 PORP, 45 TORP) were used for reconstruction of the ossicular chain. A range of five different sizes for partial and total protheses suits all implantation needs. The shape of the implants can be altered by bending. Time consuming intraoperative shaping and trimming is avoided. RESULTS: At a follow-up time of three months (33 patients) and six months (17 patients), no adverse reactions or extrusions occurred. Biologic fixation between the foot of the partial prothesis and the head of the stapes was found eight months after implantation. A hearing result of 0-20 dB residual air-bone gap was achieved in 79%. CONCLUSION: Titanium middle ear implants show good bio-compatibility and are readily integrated into the ossicular chain. Although delicate in shape, they offer excellent mechanical properties in respect to sound conduction and implantation. Initial results show Titanium to be a perfect implant material for middle ear prostheses, although long-term results are not yet available.

[Experimental changes of the pH in the middle ear and its effect on the internal ear (author's transl)]. / Experimentelle pH-Veränderungen im Mittelohr und ihre Wirkung auf das Innenohr

Irrespective of their highly differing pH-value many pharmaca are nowadays applied to the middle ear. Animal experiments are to answer the question, weather changes in the pH-value of the middle ear may cause internal ear damages, With local application of different buffers (2.3-9.1 pH) into the tympanic cavity, the membrane of the round window was examined by means of the surface preparation technique, the pH-value of the perilymph was measured and the hair cells of the organ of corti were counted and histologically evaluated. With the reduction of the pH-value in the middle ear from 4.0 to 2.3 an increasing damage of the round window membrane could be detected. The pH-value of the perilymph, however, showed only a slight statistical variation, which cannot be guaranteed. After multiple applications of extremely acid buffers into the tympanic cavity directly before the round window membrane, a small but statistically significant reduction in the pH-value of the perilymph could be noticed. Hair cell damages at the organ of corti could in no case be observed.