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3D Anatomy of the Cochlea for Cochlear Implant Hisaya Tanioka, MD, PhD 1 ; Kimitaka Kaga, MD,PhD 2 1 Dept of Radiology, Tanioka Clinic 2 National Institute of Sensory Organs, National Tokyo Medical Center, JAPAN INTRODUCTION METHODS and SUBJECTS CONCLUSIONS RESULTS REFERENCES ABSTRACT Hisaya Tanioka, MD, PhD Tanioka Clinic, Tokyo Tanioka bldg 3F, 6-24-2 Honkomagome, Bunkyo-ku, Tokyo, 113-0021 JAPAN Email: [email protected] PURPOSE: ３D anatomy of the cochlear with direct volume rendering as virtual surgery to cochlear implant. OBJECTIVE: This study was to create a three-dimensional anatomy of the round window to hook region to identify the optimal site for cochleostomy in cochlear implantation and other endocochlear surgical procedures. SUBJECTS and METHODS: 10 normal ears were studied. To develop 3D reconstructed inner ear image based on high-resolution temporal bone images obtained by a spiral CT. The axial data was applied to create 3D images on the CT work station for post processing with the use of current workstation software (GE Advantage Navigation). RESULTS: The anatomy of the round window to hook region is complex, and spatial relationships can be difficult to evaluate using two-dimensional CT images. Three-dimensional models of the round window membrane, cochlear duct, scala vestibule, scala tympani, ductus reuniens and surrounding structures were generated. The relationship between these structures and the round window membrane and adjacent otic capsule was easily identified. CONCLUSION: This three-dimensional model has implications for surgical procedures to the inner ear that aim to minimize insertional trauma and operation time. We can know the anatomical information before cochlear implant. METHODS Scanning parameters were 120kv and 120mA. Scanning was performed using collimation and pitch values of 1.00mm and 0.50 respectively[3], and the dose of radiation exposure was that the range of DLP (Dose Length Product) was 48~56mGy/cm, that was about 0.1msV. [4] The axial data were applied to create 3D volume rendering images (VR) on the CT work station for post processing with the use of current workstation software (GE Advantage Navigation). SUBJECTS 10 normal ears were studies. ( average age: 48 years old, male to female 3:2) The absence of basal cochlear trauma may be a major factor in cochlear implantation with the aim of hearing preservation. Smooth implantations via the RWM resulted in deep, atraumatic insertions into the scala tympani. Before CI operation, surgeons can know 3D detailed cochlear anatomy by this method. Anatomic studies examining the possible variances of structures lying within the cochlear should shed light on the mechanism of basal cochlear trauma. 3D anatomy of the cochlea with direct volume rendering as virtual surgery to cochlear implant. This study was to create a 3D anatomy of the round window to hook region to identify the optimal site for cochleostomy in cochlear implantation and other endochclear surgical procedure[1,2]. 1. Wardlop P, Whinney D, Rebescher SJ, et al. A temporal bone study of insertion trauma and intracochlear position of cochlear implant electrode I: comparison of Nucleus banded and Nucleus Contour™ electrodes. Hearing Research 2005; 1-2, 55-67, and 68-79. 2. Klenzner T, Richter B, Nagursky H, et al. Evaluation of the insertion-trauma of Nucleus® Counter Advance™ electrode-array in a human temporal bone model. Laryngo-Rhino-Otologie 2004; 83: 840-844. 3. Tanioka H, Kaga K. Standardized virtual endoscopy of the middle ear; normal anatomy and pathological conditions. In; O. Nuri Ozgirgin, Editor. Surgery of the ear current topics. Ankara-Turkey: REKMAY, 2009. pp. 233-239 4. European Guidelines on Quality for computed Tomography, EUR16262 5. Anson BJ, Warphea RL, Rensink MJ. The gross and macroscopic anatomy of the labyrinths. Ann otol 1968; 77: 583-606. 6. Anson BJ, Donaldson JA. Surgical anatomy of the temporal bone, 3 rd edn. Philadelphia: Saunders; 1981. SP 328 CONTACT
