[Lyophilized bone homografts in reconstructive surgery of the middle ear]

The authors present their experience with stored lyophilized bone allografts utilized in middle ear reconstructive surgery. The implants were cut from the cortical substance of the long bone in subjects deceased. A demineralization in 0.6 N HCl solution was performed in order to induce osteoinductive capacity to the bone matrix. From November 1986 to December 1988 this material was utilized in 45 operations: 31 canal up techniques; 7 canal down techniques; 4 anatomical and functional rehabilitation of old radical cavities. Good anatomical results without perforation of the tympanic membrane and without signs of inflammation or retraction were obtained in 33 cases (79%). Furthermore, no extrusion was observed in cases with retraction of the graft and protrusion of the prosthesis. In cases in which the homografts were utilized for ossiculoplasty, the post-operative air-bone gap was 21 dB and the mean hearing gain was 15 dB. The histological examination of two homografts, removed 13-18 months after implantation, appeared to be coated with normal mucosa and to contain areas of active bone formation.