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

Zou J, Lähelmä J, Koivisto J, Dhanasingh A, Jolly C, Aarnisalo A, Wolff J, Pyykkö I - Acta Otolaryngol. (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere , Tampere , Finland.

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.

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Electrode array types.
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Figure 0001: Electrode array types.

Mentions: The following electrodes were provided by MED-EL, Innsbruck, Austria (Figure 1, Table I). The standard electrode has 12 pairs of stimulating contacts made of platinum with an active stimulation length of 26.4 mm (2.4 mm contact separation). Flex28 is thinner and more flexible than the standard electrode and has seven pairs of stimulating contacts in the basal part and a single line of five contacts in the apical part with an active stimulation length of 23.1 mm. The third type is an experimental electrode array with 36 stimulating contacts arranged in a single line and extended with an active stimulation length of 28 mm. More details on the electrode dimensions are given in Table I. Six formaldehyde-preserved human temporal bones were implanted with these electrodes in the Temporal Bone Lab of Tampere University Hospital through an atraumatic round window membrane (RWM) insertion. The round window niche was exposed through a posterior tympanotomy and mainly the anterior bony overhang of the round window niche was removed. A transverse incision was made across the RWM and a defined electrode was carefully inserted into the scala tympani through the incised RWM. The rest of the electrode was coiled inside the drilled mastoid cavity and packed with tissue pieces.


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

Zou J, Lähelmä J, Koivisto J, Dhanasingh A, Jolly C, Aarnisalo A, Wolff J, Pyykkö I - Acta Otolaryngol. (2015)

Electrode array types.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4487572&req=5

Figure 0001: Electrode array types.
Mentions: The following electrodes were provided by MED-EL, Innsbruck, Austria (Figure 1, Table I). The standard electrode has 12 pairs of stimulating contacts made of platinum with an active stimulation length of 26.4 mm (2.4 mm contact separation). Flex28 is thinner and more flexible than the standard electrode and has seven pairs of stimulating contacts in the basal part and a single line of five contacts in the apical part with an active stimulation length of 23.1 mm. The third type is an experimental electrode array with 36 stimulating contacts arranged in a single line and extended with an active stimulation length of 28 mm. More details on the electrode dimensions are given in Table I. Six formaldehyde-preserved human temporal bones were implanted with these electrodes in the Temporal Bone Lab of Tampere University Hospital through an atraumatic round window membrane (RWM) insertion. The round window niche was exposed through a posterior tympanotomy and mainly the anterior bony overhang of the round window niche was removed. A transverse incision was made across the RWM and a defined electrode was carefully inserted into the scala tympani through the incised RWM. The rest of the electrode was coiled inside the drilled mastoid cavity and packed with tissue pieces.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere , Tampere , Finland.

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.

Show MeSH
Related in: MedlinePlus