Inactivated homografts in reconstructive middle ear surgery

This study examined the effects of NaOH inactivation techniques on mechanical homograft properties. The clinical data of ten implanted patients are presented. Thirty-three normal ossicles received either treatment with 1. NaOH, 2. NaOH followed by autoclaving, 3. NaOH followed by freeze-drying, or 4. no treatment. All ossicles underwent destructive axial compression in a mechanical testing machine measuring force and displacement. Compared to controls, NaOH-treated ossicles showed a significant decrease in material properties' ultimate strength and elastic modulus. The additional treatments of freeze-drying and autoclaving caused no significant deterioration of mechanical properties. The anatomical and audiological results of implanted patients were comparable to those of patients implanted with untreated or formalin-cialit treated homografts. No adverse effects or extrusions were observed. The combined NaOH-autoclave inactivation procedure produces similar material homograft changes and clinical and audiological results that are similar to NaOH treatment alone and also to effects of older form-aldehyde/cialit treatments.