Rasim Yilmazer1,2, Emrah Karatay3, Sevtap Akbulut4, Zeynep Alkan4, Basar Sarikaya5. 1. Department of Otolaryngology, Demiroglu Bilim University Hospital, Istanbul, Turkey. ryno78@gmail.com. 2. Florence Nightingale Atasehir Hastanesi, Kulak Burun Bogaz Anabilim Dali, Kuçukbakkalkoy Mahallesi, Isiklar Cd. 35/A, 34750, Atasehir/Istanbul, Turkey. ryno78@gmail.com. 3. Department of Radiology, Kartal Dr. Lutfi Kirdar Education and Research Hospital, Istanbul, Turkey. 4. Department of Otolaryngology, Yeditepe University Hospital, Istanbul, Turkey. 5. Department of Radiology, University of Washington, Seattle, WA, USA.
Abstract
PURPOSE: In this study, we aimed to introduce the facial nerve as a new anatomical landmark which can be used in ossified cochleas during cochlear implantation. We also set out to define a safe line to preserve the internal auditory canal (IAC) while drilling the basal turn of the cochlea. METHODS: Thirty patients who had temporal computed tomography (CT) were studied. The distances from the facial nerve and the round window to the IAC, carotid artery, and jugular bulb were measured in the reformatted CT images. We have created a line in the direction of the stapedial tendon from the round window to the IAC and called it ROWIAC (Round window-IAC) line. We have investigated whether this line intersects the IAC and measured the distances from this line to the IAC. RESULTS: Fifty-four temporal CT scans were included to the study. The mean distances from the facial nerve to the IAC, carotid artery, and jugular bulb were 8.8 ± 0.9, 15.0 ± 2.0, and 12.2 ± 2.9 mm, respectively. The mean distances from the round window to these structures were 3.8 ± 0.7, 9.4 ± 2.2, and 8.3 ± 2.9 mm, respectively. ROWIAC line did not intersect the IAC in any of the patients. The mean distance between this line and the IAC was 0.8 ± 0.4 mm. CONCLUSION: We propose that facial nerve and ROWIAC line can be used as potential landmarks during cochlear implantation in ossified cochleas to protect the adjacent neurovascular structures.
PURPOSE: In this study, we aimed to introduce the facial nerve as a new anatomical landmark which can be used in ossified cochleas during cochlear implantation. We also set out to define a safe line to preserve the internal auditory canal (IAC) while drilling the basal turn of the cochlea. METHODS: Thirty patients who had temporal computed tomography (CT) were studied. The distances from the facial nerve and the round window to the IAC, carotid artery, and jugular bulb were measured in the reformatted CT images. We have created a line in the direction of the stapedial tendon from the round window to the IAC and called it ROWIAC (Round window-IAC) line. We have investigated whether this line intersects the IAC and measured the distances from this line to the IAC. RESULTS: Fifty-four temporal CT scans were included to the study. The mean distances from the facial nerve to the IAC, carotid artery, and jugular bulb were 8.8 ± 0.9, 15.0 ± 2.0, and 12.2 ± 2.9 mm, respectively. The mean distances from the round window to these structures were 3.8 ± 0.7, 9.4 ± 2.2, and 8.3 ± 2.9 mm, respectively. ROWIAC line did not intersect the IAC in any of the patients. The mean distance between this line and the IAC was 0.8 ± 0.4 mm. CONCLUSION: We propose that facial nerve and ROWIAC line can be used as potential landmarks during cochlear implantation in ossified cochleas to protect the adjacent neurovascular structures.