Mediterr. J. Otol 2008; 4:(1)

The Cochlear-Carotid Interval: Preoperative Assessment for Cochlear Implant

Eshrak Hassanein, Eman Geneidi, Mohamed Taha

Departments of Radiology, and Otorhinolaryngology, Ain- Shams University Hospital, Faculty of Medicine, Cairo-Egypt dreshrak65@hotmail.com

Objective: To establish reference measurements in a sample of Egyptian population for the region between the basal turn of choclea and petrous internal carotid artery, which is termed the "cochlear-carotid interval" in order to investigate the range of safe normal variation before cochlear implant surgery.

Material and method:  We examined 42 patients by high resolution CT of temporal bone. Two readers independently measured the bony interval between the cochlea and the petrous internal carotid artery canal.

Results: Two patients were eliminated from study due to motion artifact. In total, we examined 40 patients. Cochlear-carotid interval on right side ranged from 1.0 to 3.4mm (Mean, 2.3 ± SD 0.6) and from 1.0 to 3.0 mm (Mean, 2.1 ± SD 0.5) on left side. Patients were grouped into five groups according to the measurement of their cochlear-carotid interval.

Conclusion: Cochlear-carotid interval varies widely between patients; it may be very thin or absent. Preoperative knowledge of patients' group is important to determine the potential risk of carotid canal injury in cochlear implant surgery.