Imaging cochlear implantation with round window insertion in human temporal bones and cochlear morphological variation using high-resolution cone beam CT

Abstract

Conclusions: The present experimental set-up of high spatial resolution cone-beam computed tomography (CBCT) showed advantages of demonstrating the critical landmarks of the cochlea in identifying the position of intracochlear electrode contacts and has the potential for clinical application in cochlear implant (CI) surgery. Objective: To evaluate a newly developed CBCT system in defining CI electrode array in human temporal bone and cochlear morphological variation. Methods: Standard electrode, flexible tip electrode (Flex28), and an experimental electrode array with 36 contacts from MED-EL were implanted into the cochleae of six human temporal bones through an atraumatic round window membrane insertion. The cochleae were imaged with 900 frames using an experimental set-up based on a CBCT scanner installed with Superior SXR 130-15-0.5 X-ray tube in combination with filtration of copper and aluminum. Results: In all temporal bones, the landmarks of the cochlea, modiolus, osseous spiral lamina, round window niche, and stapes were demonstrated at an average level of 3.4–4.5. The contacts of electrode arrays were clearly shown to locate in the scala tympani. There was a linear correlation between the ‘A’ value and cochlea height, and between the A value and actual electrode insertion length for the first 360° insertion depth.

Applicability of vital staining and tissue clearing to vascular anatomy and melanocytes' evaluation of temporal bone in six laboratory species

“…An exact understanding of the labyrinth's inner structure is difficult to ascertain due to its complexity and the investing hard surrounding temporal bone. To understand its structural framework, researchers and surgeons have had to rely on illustrations derived from 2 dimensional histological images, 3‐dimensional reconstruction of labyrinthine bone and surgical dissection images (Buytaert et al, ; Lee et al, ; Zou et al, ). However, histopathologic studies of the membranous labyrinth have been limited to 2‐dimensional staining methods.…”

“…Most morphological analyses use 2‐dimensional images created through histological methods, even though 3‐dimensional techniques exist. For examples, micro CT, scanning Thin‐Sheet Laser Imaging Microscopy, optical micro‐angiography, optical coherence tomography and scanning laser optical tomography have all been tried as 3‐dimensional tools to understand the anatomy and demonstrate the relationship among the various structures (Buytaert, Johnson, Dierick, Salih, & Santi, ; Choudhury, Chen, Shi, Nuttall, & Wang, ; Lee et al, ; Lee, Park, Kang, & Choung, ; Tinne et al, ; Zou et al, ). Unfortunately, these, computer‐assisted reconstructed images have provided limited information when trying to study the in vivo anatomy.…”

Imaging of Temporal Bone

“…Rated as: -= not visible, += poorly, ++= moderately and +++= good visible. (6) (54) visualization of the cochlear partitioning (9). A recent paper by Maillot et al (12) indicated that MDCT allows radiologists to examine the complex anatomy of the temporal bone with sub-millimeter resolution and is the first modality of choice.…”

“…CBCT appears to provide sufficient spatial accuracy for intraoperative usage during temporal bone surgery (32) (27). Identifying the location of implants is becoming increasingly important in modern otology, which involves applications such as the Vibrant Soundbridge implant and CI (6,33) They showed that insufficient image-quality scores were more frequent in low-dose scans versus high-dose scans, however, the difference was only statistically significant for otologists but not for neuroradiologists. Image quality was critical for small structures (such as the stapes or lamella at the internal auditory canal fundus).…”

“…Imaging of the temporal bone by using both MRI and MDCT is likely the future gold standard for temporal bone imaging (2). Some recent and novel imaging methods used experimentally in temporal bones have not yet been applied clinically such as optical coherence tomography imaging (3) (4) (5), microtomography (µCT) (6) and endoscopes using coherent anti-Stokes Raman spectroscopy (CARS) technique (7) these (7), development of advanced of contrasting agents (8) and these may provide additional imaging benefits in the future. This chapter provides an overview of current temporal bone imaging methods and a review of emerging concepts in temporal bone imaging technology.…”