High-resolution cone-beam computed tomography: a potential tool to improve atraumatic electrode design and position

Abstract

Conclusions: Flat-panel cone-beam computed tomography (CBCT) is able to assess the trajectory of the implanted cochlear implant (CI) array. This is essential to determine specific effects of electrode design and surgical innovations on outcomes in cochlear implantation. CBCT is a non-invasive approach yielding similar data to histopathological analyses, with encouraging potential for use in surgical, clinical and research settings. Objectives: To examine the fidelity of CBCT imaging and custom 3D visualization in characterizing CI insertion in comparison to gold standard, histopathological examination. Methods: Eleven human temporal bones were implanted with the ‘Straight Research Array’ (SRA). Post-insertion, they were imaged with a prototype mobile C-arm for intraoperative CBCT. Post-acquisition processing of low-dose CBCT images produced high-resolution 3D volumes with sub-millimetre spatial resolution (isotropic 0.2 mm³ voxels). The bones were resin impregnated and sectioned for light microscopic examination. Dimensional electrode characteristics visible in section images were compared with corresponding CBCT images by independent observers. Results: Overall, CBCT demonstrated adequate resolution to detect: 1) scala implanted; 2) kinking; 3) number of intracochlear contacts; 4) appropriate ascension of the array; and overall confirms ideal insertion. CBCT did not demonstrate adequate resolution to detect reversal of electrode contacts or basilar membrane rupture.

Keywords::

• Cochlear implant
• electrode array
• flat detector computed tomography

Acknowledgements

This work was supported by the Kevin and Sandra Sullivan Chair in Surgical Oncology, the RACH Fund and the Hatch Engineering Fund. Initial development of the C-arm prototype was performed in collaboration with Siemens Healthcare (Siemens XP, Erlangen Germany).

Declaration of interest: Claudiu Treaba is an employee of Cochlear Corporation. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.