Distances between the cochlea and adjacent structures related to cochlear implant surgery.

A sound knowledge of the topographic anatomy of the cochlea, especially of the distances between it and the adjacent structures, is essential for otosurgery in general, and in surgical procedures for cochlear implantation in particular. One hundred temporal bones of humans aged from one month to 71 years, of either sex, taken from both body sides (but not bilaterally) were studied by dissection under the operating microscope and exposing the cochlea and its neighbourhood. The minimal distances were measured between the cochlear turns and the internal carotid artery, the bulb of the jugular vein, the facial nerve and the floor of the internal acoustic meatus. It was found that in children aged up to 4 years most of the measured distances were significantly smaller than in older individuals. Only the minimal distance between the basal turn of the cochlea and the floor of the internal acoustic meatus was shorter in small children without statistical significance.