An observational, prospective study to evaluate the preoperative planning tool “CI-Wizard” for cochlear implant surgery

Improving rehabilitation of deaf patients by advanced imaging before cochlear implantation

INTRODUCTION

Cochlear implants have advanced the management of severe to profound deafness. However, there is a strong disparity in hearing performance after implantation from one patient to another. Moreover, there are several advanced kinds of imaging assessment before cochlear implantation. Microstructural white fiber degeneration can be studied with Diffusion weighted MRI (DWI) or tractography of the central auditory pathways. Functional MRI (fMRI) allows us to evaluate brain function, and CT or MRI segmentation to better detect inner ear anomalies.

OBJECTIVE

This literature review aims to evaluate how helpful pre-implantation anatomic imaging can be to predict hearing rehabilitation outcomes in deaf patients. These techniques include DWI and fMRI of the central auditory pathways, and automated labyrinth segmentation by CT scan, cone beam CT and MRI.

DESIGN

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were selected by searching in PubMed and by checking the reference lists of relevant articles. Inclusion criteria were adults over 18, with unilateral or bilateral hearing loss, who had DWI acquisition or fMRI or CT/ Cone Beam CT/ MRI image segmentation.

RESULTS

After reviewing 172 articles, we finally included 51. Studies on DWI showed changes in the central auditory pathways affecting the white matter, extending to the primary and non-primary auditory cortices, even in sudden and mild hearing impairment. Hearing loss patients show a reorganization of brain activity in various areas, such as the auditory and visual cortices, as well as regions involved in language and emotions, according to fMRI studies. Deep Learning's automatic segmentation produces the best CT segmentation in just a few seconds. MRI segmentation is mainly used to evaluate fluid space of the inner ear and determine the presence of an endolymphatic hydrops.

CONCLUSION

Before cochlear implantation, a DWI with tractography can evaluate the central auditory pathways up to the primary and non-primary auditory cortices. This data is then used to generate predictions on the auditory rehabilitation of patients. A CT segmentation with systematic 3D reconstruction allow a better evaluation of cochlear malformations and predictable difficulties during surgery.

Vorstellung und Evaluation des haptisch-visuellen, ohrchirurgischen Trainingssystems „HaptiVisT“

Hintergrund Operationen am Felsenbein stellen eine besondere Herausforderung für HNO-Chirurgen dar. Ziel des BMBF-geförderten Projektes war die Entwicklung eines realitätsnahen Trainingssystems für Ohroperationen in Form eines „Serious Game“.

Methodik Der vorgestellte Prototyp des HaptiVisT-Systems fungiert als ohrchirurgisches Trainingssystem mit visueller Rückkopplung durch einen brillenlosen 3D-Monitor und haptischer Rückkopplung durch einen den Bohrer simulierenden Haptik-Arm. Eine Vielfalt von Trainingsmöglichkeiten wird durch 3 verfügbare chirurgische Prozeduren (Antrotromie, Mastoidektomie, posteriore Tympanotomie) gewährleistet. Ein gewichtetes Punktesystem ermöglicht die Messbarkeit des Trainingserfolgs. Im Zuge der technischen Entwicklung des Prototyps erfolgte eine prospektive Evaluation durch 8 HNO-Ärzte und 4 Studierende u.a. hinsichtlich der Lerninhalte und Benutzerfreundlichkeit. Zur Anwendung kam ein standardisierter Fragebogen (Ordinalskala: 1=sehr gut bis 5=sehr schlecht).

Ergebnisse Hinsichtlich der Lerninhalte ergaben die Aspekte „Festigung Anatomie (Mittelwert=1,58)“, „Training Hand-Augen-Koordination (1,67)“, „Übertragbarkeit in die Praxis (1,83)“ und „Nützlichkeit für die Praxis (1,33)“ gute bis sehr gute Werte. Die Benutzerfreundlichkeit zeigte für die Aspekte „Realitätsnähe (2,29)“, „Zusammenspiel Haptik und Optik (2,33)“ sowie „Immersion in das Trainingssystem (1,89)“ ebenfalls gute Werte. Der „Motivationsfaktor“ war bei allen Testpersonen sehr hoch (1,2).

Schlussfolgerung Das ohrchirurgische Trainingssystem HaptiVisT bietet die Möglichkeit des immersiven Trainings von Ohroperationen. Eine Integration in den klinischen Alltag und insbesondere in die ärztliche Weiterbildung zum HNO-Facharzt erscheint daher sinnvoll.

Surgical approach to the facial recess influences the acceptable trajectory of cochlear implantation electrodes

PURPOSE

To provide practical guidance to the operative surgeon by mapping the location, where acceptable straight-line virtual cochlear implant electrode trajectories intersect the facial recess. In addition, to investigate the influence of facial recess preparation, virtual electrode width and surgical approach to the cochlea on these available trajectories.

METHODS

The study was performed on imaging data from eight cadaveric temporal bones within the University of Melbourne Virtual Reality (VR) Temporal Bone Surgery Simulator. The facial recess was opened to varying degrees, and acceptable trajectory vectors with varying diameters were calculated for electrode insertions via cochleostomy or round window membrane (RWM). The percentage of acceptable insertion vectors through each location of the facial recess was visually represented using heatmaps.

RESULTS

Seven of the eight bones allowed for acceptable vector trajectories via both cochleostomy and RWM approaches. These acceptable trajectories were more likely to lie superiorly within the facial recess for insertion via the round window, and inferiorly for insertion via cochleostomy. Cochleostomy insertions required a greater degree of preparation and skeletonisation of the junction of the facial nerve and chorda tympani within the facial recess. The width of the virtual electrode had only marginal impact on the availability of acceptable trajectories. Heatmaps emphasised the intimate relationship the acceptable trajectories have with the facial nerve and chorda tympani.

CONCLUSION

These findings highlight the differences in the acceptable straight-line trajectories for electrodes when implanted via the round window or cochleostomy. There were notable exceptions to both surgical approaches, likely explained by the variation of hook region anatomy. The methodology used in this study holds promise for translation to patient specific surgical planning.

The Literature of Chemoinformatics: 1978-2018

This article presents a study of the literature of chemoinformatics, updating and building upon an analogous bibliometric investigation that was published in 2008. Data on outputs in the field, and citations to those outputs, were obtained by means of topic searches of the Web of Science Core Collection. The searches demonstrate that chemoinformatics is by now a well-defined sub-discipline of chemistry, and one that forms an essential part of the chemical educational curriculum. There are three core journals for the subject: The Journal of Chemical Information and Modeling, the Journal of Cheminformatics, and Molecular Informatics, and, having established itself, chemoinformatics is now starting to export knowledge to disciplines outside of chemistry.