The Internal Dimensions of the Cochlear Scalae With Special Reference to Cochlear Electrode Insertion Trauma

Abstract

Various attempts have been made to evaluate the dimensions of the cochlea related to cochlear implantation. Little attention was paid to the distinct narrowing of the scala tympani in the region of the ascending part of the cochlear duct, although from the literature, it is known that electrode insertion trauma frequently occurs here. Individual variations of the cochlear micromorphology may additionally contribute to the failure of preformed electrode arrays, but the challenge of guiding the electrode array around the first bend of the cochlear turn, that is, the pars ascendens, is obviously impaired by the interindividually constant narrowing in this area. Therefore, this finding may have implications on the development of electrode designs and insertion methods.

Automated analysis of human cochlea shape variability from segmented μ CT images

“…Irrespective to the parametrization, our crosssections measurements are very similar to the ones from Wysocki (1999) and Thorne et al (1999), our height measurements being also comparable with diameter measurements obtained from inscribed circles (Biedron et al, 2010;Avci et al, 2014). Tympanic cross-section area appears greater to the vestibular one in the basal turn and conversely in the middle and apical turns (as shown in Fig .16b) match with Gulya and Steenerson (1996); Wysocki (1999)'s observations.…”

“…In order to evaluate the internal dimensions of the cochlea, cross-section measurements were performed in radial planes (a.k.a mid-modiolar cross-sections) (Zrunek et al, 1980;Zrunek and Lischka, 1981;Erixon et al, 2009), in parallel planes such as histological sections (Biedron et al, 2010) and in planes normal to the centerline (Poznyakovskiy et al, 2011;Avci et al, 2014). This last method does not induce measurement errors (e.g.…”

“…Histological sections offer the best image resolutions for the examination of fine cochlear structure (Hardy, 1938;Gulya and Steenerson, 1996;Biedron et al, 2010;Makary et al, 2010). However just as plastic casts and microdissection it is a destructive method.…”

“…Previous analyses include measurements of the length of the cochlea and the number of cochlear turns (Hardy, 1938;Kawano et al, 1996;Skinner et al, 2002;Escudé et al, 2006;Stakhovskaya et al, 2007;Erixon et al, 2009;Gunz et al, 2012;Shin et al, 2013;van der Marel et al, 2014), measurements of the heights, widths and sectional areas of the scala tympani (Zrunek et al, 1980;Zrunek and Lischka, 1981;Hatsushika et al, 1990;Gulya and Steenerson, 1996;Wysocki, 1999;Thorne et al, 1999;Biedron et al, 2010;Avci et al, 2014), the scala vestibuli (Zrunek and Lischka, 1981;Gulya and Steenerson, 1996;Wysocki, 1999;Thorne et al, 1999;Biedron et al, 2010) and the cochlea (Erixon et al, 2009;Shin et al, 2013), measurements of the radial component of the cochlear centerlines (also called cochlear curvature) (Cohen et al, 1996;Baker, 2008;van der Marel et al, 2014), and studies of the longitudinal component of the centerlines of the scala tympani (Avci et al, 2014) and the cochlea itself (Verbist et al, 2009).…”

Insertionsergebnisse von Contour™- und Contour-Advance™-Elektroden

“…Im Vergleich zu den Ergebnissen von Lane et al [19] sind die Ergebnisse unserer Untersuchung in Bezug auf die chirurgische Qualität (Scala-tympani-Insertionsrate und Dislokationsrate) vergleichbar. Ein gewisser Anteil an Dislokationen erscheint aufgrund der individuellen Anatomie der Scala tympani, die für den Chirurgen nicht einschätzbar ist, nicht vermeidbar zu sein [8].…”