These preliminary results suggest that the degree of damage to the lateral cochlear wall may play an important role in influencing the amount of new tissue formation following cochlear implantation. Intracochlear new tissue does not appear to be an important determinant of performance as measured by word recognition scores or the total number of remaining spiral ganglion cells.

The formation of new bone and fibrous tissue in the human inner ear following cochlear implantation was evaluated by computer-assisted 3-D reconstruction. Seven temporal bones from patients who in life had undergone cochlear implantation were prepared for histological study with the implant in situ. The specimens were sectioned in the axial plane at a thickness of 20 µm. At least every tenth section was digitally reconstructed in three dimensions and volumes of new bone and fibrous tissue were calculated per millimeter length of the cochlea. New bone and fibrous tissue were found in all seven specimens, particularly at the cochleostomy site. In addition, new bone and fibrous tissue had extended to variable lengths along the track of the cochlear implant and in some cases extended beyond the distal end of the implanted electrode. This methodology provides a quantitative tool for evaluation of new bone and fibrous tissue in the inner ear following implantation. This should assist in correlating psychophysical and speech perception tests with intracochlear pathology, evaluating both electrode design and the techniques of preserving residual auditory function.

Hypothesis-The goal of this study was to create a three-dimensional model of the anatomy of the hook region to identify the optimal site for cochleostomy in cochlear implant surgery.Background-The anatomy of the hook region is complex, and spatial relationships can be difficult to evaluate using two-dimensional histological slides or cadaveric temporal bones.