[Titanium as a material for ossicular replacement - basic aspects and clinical application].
BACKGROUND
The use of titanium as a biomaterial in ossicular chain reconstruction is increasing. The situation for integration of biomaterials is more difficult in the semiopen implantation site middle ear than in other parts of the body. Important for integration is the contact of the biomaterial's surface toward proteins. Studies of the integration in living tissue still have to be performed in animal experiments. Morphological examinations of explanted prostheses after clinical use complete the picture of an ossicular replacement material.


METHODS
Preclinical studies where performed to compare the adsorption behaviour of titanium, stainless steel and aluminum oxide toward radioactive marked albumin and native collagen type I. An animal model in the rabbit was performed to study the integration of titanium in the middle ear morphologically. Middle ear prostheses removed during revision surgery were studied as well.


RESULTS
Titanium showed an adsorption amount of 360 microgram/cm(2), stainless steel of 230 microgram/cm(2) and aluminum oxide of 500 microgram/cm(2) out of an albumin solution of 400 mg/ml. Comparing desorption the mean loss was 16 % for titanium, 21 % for stainless steel and 23 % for aluminium oxide. Reassembled collagen fibrils could be detected after adsorption in collagen type I solution by means of scanning electron microscopy. Morphological studies in animal experiments showed regular healing after implantation. Explanted prostheses from humans did not show any cellular signs of repulsion.


CONCLUSIONS
The results of preclinical studies and clinical use demonstrate titanium as a useful material for ossicular reconstruction in middle ear surgery.
Schwager
K
K
Klinik und Poliklinik für Hals-Nasen-Ohrenkranke der Universität Würzburg, Germany. k.schwager@mail.uni-wuerzburg.de
D000042:Absorption; D000537:Aluminum Oxide; D000818:Animals; D018424:Cholesteatoma, Middle Ear / Q000473:pathology; D024042:Collagen Type I / Q000378:metabolism; D005549:Foreign-Body Reaction / Q000473:pathology; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009998:Ossicular Prosthesis; D011474:Prosthesis Design; D011817:Rabbits; D012086:Reoperation; D012709:Serum Albumin / Q000378:metabolism; D013193:Stainless Steel; D014025:Titanium
D024042:Collagen Type I; D012709:Serum Albumin; D013193:Stainless Steel; D014025:Titanium; D000537:Aluminum Oxide