Experience with freeze-dried dura mater and bone in tympanoplasties

Abstract

In cases with very large perforations (subtotal defect) the reconstruction of the eardrum by free transplanted grafts of fascia can be difficult from the technical point of view. We try to master this problem by using a double graft consisting of an eardrum-like disk of freeze-dried dura mater (preserve), covered by normal endogenous temporal fascia. The dura disk, well adapted on the prepared limbus of the remaining eardrum, is not only a mechanical protection of the fascia but also a support of its nutrition, because it is quickly organized by granulation tissue well supplied with blood. The dura disappears after 3 weeks by absorption, leaving behind the meanwhile settled graft of fascia.

The implantation of freeze-dried bone into the tympanic cavity is always unsuccessful because the bone will not be tolerated and will be completely absorbed within a few days. Examinations on animals showed that there are no immunological and histological findings of an allergic response. The process of lyophilization seems to remove the premise of an immunological reaction.

Among a total of 240 myringoplasties we had 62 patients with large defects of the eardrum without suppuration. There were good results without any complication in 95 %. No relapsing perforations were observed for 2 years and the sound conduction became normal.