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ABSTRACT: To evaluate histologically the risk of trauma to intracochlear structures after sequential insertion of an intracochlear catheter and an electrode array.
A previous computed tomographic scan-based study demonstrated that introduction of a flexible disposable intracochlear catheter for drug delivery to a distance of up to 15 mm was feasible and showed no radiologic evidence of basilar membrane trauma.
Fifteen fresh human temporal bones were prepared for cochlear implantation. We sequentially performed the introduction of the catheter, the injection of 15 µl of an iodine solution into the scala tympani via the catheter, and the removal of the catheter in 14 temporal bones, and finally, 2 types of electrode array (Flex EAS and Flex Soft) from MED-EL, were inserted into 10 temporal bones. The bones were fixed and embedded in methylmethacrylate to cut the undecalcified temporal bones parallel to the modiolus axis with the electrode array in place, and each histologic section was photographed to document the location and extent of trauma in the cochlea.
No specific damage (Grade 0 trauma) to cochlear structures occurred in 12 temporal bones, and elevation of basilar membrane (Grade 1 trauma) occurred in 2 cases. The electrode array was positioned in the scala tympani under the basilar membrane in all temporal bones, with one exception, in which the Flex Soft electrode array deviated behind the spiral ligament and into the scala vestibuli apically (Grade 3 trauma).
The infusion of an iodine solution within an intracochlear catheter and the subsequent insertion of an electrode array was shown to be feasible and often atraumatic.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 11/2011; 32(9):1448-54. · 1.44 Impact Factor
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ABSTRACT: 1) To assess the insertion characteristics of a disposable intracochlear catheter; and 2) to assess radiologically cochlear trauma induced by delivery catheter and electrode arrays.
A catheter was designed to enter the scala tympani up to 15 mm and to acutely deliver pharmacological agents during cochlear implantation.
A cadaveric study was conducted in accordance to national regulation. Thirteen fresh temporal bones were evaluated radiologically. The intracochlear catheter used in this experiment has the same outer dimensions and profile as a standard MED-EL cochlear implant electrode array. We performed sequentially the introduction of the catheter, the injection of an iodine solution into the scala tympani via the catheter, the removal of the catheter, and finally an electrode array insertion. Ten to 15 μl of an iodine solution was injected into the scala tympani at depth of 15 mm. Four CT scans were sequentially performed after each step.
The disposable intracochlear catheter could easily be inserted in all specimens. An insertion at depth of 15 mm was easily achieved every time. CT scans demonstrated that the iodine solution injected stayed in the scala tympani in all specimens. This was interpreted as indirect evidence of the integrity of the basilar membrane.
Drug delivery during cochlear implantation using a flexible disposable intracochlear catheter has been demonstrated to be feasible and without radiological evidence of basilar membrane trauma to a distance of up to 15 mm, as demonstrated in 13 temporal bones.
Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 02/2011; 32(2):217-22. · 1.44 Impact Factor
Cochlear implants international 01/2010; 11 Suppl 1:434-6.
Cochlear implants international 01/2010; 11 Suppl 1:431-3.