Accuracy of radiological prediction of electrode position with otological planning software and implications of high-resolution imaging

Abstract

Objectives

In cochlear implantation, preoperative prediction of electrode position has recently gained increasing attention. Currently, planning is usually done by multislice CT (MSCT). However, flat-panel volume CT (fpVCT) and its secondary reconstructions (fpVCT_SECO) allow for more precise visualization of the cochlea. Combined with a newly developed otological planning software, the position of every single contact can be effectively predicted. In this study it was investigated how accurately radiological prediction forecasts the postoperative electrode localization and whether higher image resolution is advantageous.

Methods

Utilizing otological planning software (OTOPLAN®) and different clinical imaging modalities (MSCT, fpVCT and fpVCT_SECO) the electrode localization [angular insertion depth (AID)] and respective contact frequencies were predicted preoperatively and examined postoperatively. Furthermore, inter-electrode-distance (IED) and inter-electrode-frequency difference (IEFD) were evaluated postoperatively.

Results

Measurements revealed a preoperative overestimation of AID. Corresponding frequencies were also miscalculated. Determination of IED and IEFD revealed discrepancies at the transition from the basal to the middle turn and round window to the basal turn. All predictions and discrepancies were lowest when using fpVCT_SECO.

Conclusion

The postoperative electrode position can be predicted quite accurately using otological planning software. However, because of several potential misjudgments, high-resolution imaging, such as offered by fpVCT_SECO, should be used pre- and postoperatively.

KEYWORDS:

• OTOPLAN
• radiological electrode prediction
• prediction accuracy
• cochlear planning software
• surgical planning software
• fpVCT secondary reconstruction

Acknowledgements

The authors thank the team of the Comprehensive Hearing Center at the University of Wuerzburg for their extensive help.

Disclaimer statements

Contributors None.

Funding None.

Conflicts of interest None.

Ethics approval None.

Additional information

Notes on contributors

Anja Kurz

Priv.- Doz. Dr. Anja Kurz is the head of audiology and has been the technical director of the Comprehensive Hearing Center since 2015 at the Würzburg University Hospital. She received a Master of Arts (M.A.) in communication science and technical acoustics in 2005 and an MSc in Audiology in 2007. She then worked several years for a hearing implant and hearing aid manufacturer holding different positions in product development and audiology. In 2015, she completed a PhD in Biomedical Engineering at the University of Berne, Switzerland. Her research interest is broad and currently focuses on single sided deafness, intraoperative monitoring in all implantable prosthesis and fitting cochlear and auditory brainstem implants.

Medical doctor, Prof. Dr. med. Dr. h. c. Rudolf Hagen holds the chair in Otorhinolaryngology at the University of Wuerzburg (Germany) since 2005. He graduated in medicine 1983 (MD) and finished his residency in ORL 1988. Following habilitation in 1991 (assistant professor), he became medical director of the ORL Department at the Katharinenhospital Stuttgart (Germany) in 1998 (associate professor university of Tübingen, Germany). 2005 he was appointed head of the ORL Department at the University of Würzburg and Chairman. He acquired several additional qualifications in Plastic and Reconstructive Surgery (1992), Allergology (1995) and Special Head and Neck Surgery (1996). He is author/coauthor in more than 200 peer-reviewed articles. His actual RG-score is 44.45 (ResearchGate), the h-index 27.

Medical doctor, Dr. med. Tilmann Neun. 2000-2006 Study of human medicine at the University of Würzburg. 2007-2012 resident doctor at the Institute for Diagnostic and Interventional Radiology at the Jena University Hospital. 2012-2017 doctor at the Clinic for Radiology and Nuclear Medicine in Weimar. Since 2017 doctor in the Institute for Diagnostic and Interventional Neuroradiology at the University Hospital of Würzburg.

Medical doctor, Prof. Dr. med. Kristen Rak, born in 1980. 2001-2008 Study of human medicine at the University Wuerzburg. Specialist training from 2008-2015 at the University ENT-Hospital of Würzburg. Promotion in 2010 at the Institute of Clinical Neurobiology, Würzburg. 2015 appointment as senior doctor. Habilitation in 2016. Head of the Department of hearing prosthetics and implantable hearing systems Comprehensive Hearing Center. Assistent medical director of the Clinic since 2021.

Medical doctor, Dr. med. Franz-Tassilo Müller-Graff. 2010-2016 Study of human medicine and doctorate (2019) at the University of Rostock. 2017-2018 resident doctor in trauma surgery at the University Hospital Augsburg. Since 2019 resident doctor in otorhinolaryngology at the University Hospital of Würzburg.

Medical doctor, Dr. med. Johannes Voelker studied medicine at the Universities of Erlangen and Wuerzburg/Germany. During his studies, he completed a doctoral thesis at the ENT University Clinic in Wuerzburg on the subject of neural stem cells in the auditory pathway. He has been researching in this area as a clinician scientist ever since. His areas of expertise include live cell imaging, electrophysiology, and hearing research. He is a specialist and senior physician for ear, nose, and throat medicine at the University Clinic in Wuerzburg.