Diagnosis of stapedial footplate fixation in archaeological human remains

This study analyses changes in the region of the oval window suggestive of stapedial footplate fixation in archaeological human skeletal remains. We endoscopically investigated 621 temporal bones of 385 individuals from five medieval sites in Germany to identify fixations of the stapedial footplate. For differential diagnosis, four cases suspicious of representing stapes fixation or remnants of the fixed footplate were further investigated using microscopic techniques (brightfield and darkfield imaging, phase-contrast microscopy, fluorescence microscopy, CLSM, SEM-BSE imaging), and EDX-analysis, either alone or in combination. Our findings suggest that only two of the four cases represented an intravital fixation of the stapedial footplate. The first case was diagnosed as caused by sclerosis of the annular ligament, the second cases as representing an example of congenital footplate fixation. In a third case, structures that were initially diagnosed as remnants of the footplate were shown to be soil particles. In the fourth case the structures attached to the oval window were identified as apatitic deposits formed by diagenetic agents. Our findings highlight the need for microscopic analyses to distinguish intravital from postmortem changes in the region of the oval window and the differential diagnosis of intravital footplate fixations.