Relationship of cochlea with surrounding neurovascular structures and their implication in cochlear implantation.

PURPOSE: The purpose of this investigation was to evaluate the topographic relations of cochlea with vital neurovascular structures and their implications for cochlear implantation (CI).

METHODS

Sixty cadaveric human temporal bones were microdissected to expose the basal turn (BT) of cochlea, the carotid canal, the facial canal (FC) and the jugular fossa (JF). The minimum distances of BT of the cochlea from the carotid canal, the FC and roof of the JF were measured.

RESULTS

The mean minimum distances of BT of the cochlea from the carotid canal, the FC and roof of the JF were found to be 1.38 ± 0.82, 1.06 ± 0.46 and 4.68 ± 2.21 mm, respectively. The abutment and impingement of carotid canal on anterior cochlear wall was found in three (5 %) and six (10 %) cases, respectively. Thin bone separation was observed between cochlea and FC (0.1 mm) in one case (1.67 %).

CONCLUSIONS

The preoperative knowledge of the variant anatomy of BT of cochlea in relation to adjacent vital structures like abutment and impingement of carotid canal and thin bone separation of the BT of cochlea from FC and JF is of immense importance in CI, which may otherwise lead to disastrous consequences during surgery.