[Meatoplasty with allogenic preserved cartilage. Histomorphological model in animal experiments (author's transl)].

The reconstruction of the posterior wall of the external acoustic meatus destroyed by surgery or a cholesteatoma is necessary for the complete restoration of function. For this purpose, allogen cartilage preserved in thiomersalate has been transplanted on the anterior wall of the air-containing mastoid bone in 160 clinical cases. The histomorphological reaction of the recipient to unilaterally uncovered transplant material has previously been unknown. In 10 guinea pigs, 15 fenestrated bullae (hypotympanum equivalents) were closed with cartilage transplants fixed in place with tissue adhesive. After a period varying between 7 1/2 and 11 months, the walls of the bullae with the transplant were then examined histomorphologically. Despite the variations in the period in situ, the avital cartilage transplant, which remained largely constant in volume and shape, was always to be found. It was tolerated without reaction and was "enveloped"--also on the primarily uncovered surface--by a capsule of bone and connective tissue. In no case was rejection observed. Marked foreign-body reaction was, however, found in the vicinity of the tissue adhesive, which was absorbed only slowly. The clinically well-known tissue-compatible and complication free behaviour of the allogenic cartilage transplant preserved in thiomersalate, is thus explained by the histomorphological findings. In contrast, the fact that marked foreign-body reaction was demonstrable even after almost one year, suggests that tissue adhesive should not be used.