الفهرس 
SURGICAL ANATOMY AND RELATION TO
Cochlear implantation in cochlear hypoplasiaOnly 14 pages are availabe for public view
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Abstract
Summary and conclusion
The present study’s main objective was to compare between the
two most commonly used techniques for insertion of the cochlear
implant electrode into the scala tympani of the cochlea to optimize
cochlear implantation results and to allow patients with severe to
profound SNHL to get the most benefits of their implant devices.
For that purpose, the present study recruited large sample of patients
(n = 200) and divided them equally on two groups. The first group
received the cochlear implant device through the round window
approach and named the RW group while the second group received
the cochlear implant device through the standard cochleostomy
technique and named the C group. The C group acted as a control
group for comparison and patients of both groups were evaluated
for their cochlear implantation outcomes via standardized, validated
and reliable tests for each outcome, for speech perception the
patients were tested using the CNC word recognition test and the
BKB open-set sentence recognition. For language acquisition the
patients were tested by the Preschool Language Scale-fourth edition
(PLS-4) and the Peabody Picture Vocabulary Test, Fourth edition
(PPVT-4). For speech production the patients were tested by using
the Diagnostic Evaluation of Articulation and Phonology (DEAP).
All the participants in this study had to take all the previous tests
twice after they received the cochlear implant for their results to be included in this study, the first time was between 24 to 30 months
post-implantation while the second time they were tested between
31 to 36 months post-implantation. The results of this study
indicated that patients who received cochlear implantation by using
the round window approach demonstrated significantly higher
scores in all tests regarding speech perception, language acquisition
and speech production when compared with patients who received
the device through the standard cochleostomy insertion technique.
These results were consistent with the results of several studies that
indicated that the round window insertion, being less traumatic
method for insertion of the electrode, is associated with better
electrical stimulation for the cochlear neural elements, minimal
production of fibrous tissue around the electrode, minimal
production of neo-ossification inside the cochlea and associated
with better perimodiolar placement of the electrode which brings
the electrode closer to the modiolus and the osseous spiral lamina of
the cochlea.
The present study concluded and recommends the following points:
Round window insertion is associated with better cochlear
implantation outcomes regarding speech perception, language
acquisition and speech production than the standard
cochleostomy insertion. Insertion of the electrode through the round window of the
cochlea is safe and effective method for cochlear
implantation.
In patients with favorable temporal bone anatomy, the round
window should be clearly visible and easily accessible.
However, in some cases of cochlear implantation the round
window is obscured and in that case the surgeon must look
for the round window by all available means including
widening of the facial recess opening, using angled
endoscopes or even sacrificing the chorda tympani to
visualize the round window. However, some round windows
will remain obscured for the surgeon’s view and in that case
cochleostomy will be the last choice to insert the electrode.
The new modified St Thomas’ Hospital (STH) classification
suggested by the current study is strongly recommended to be
taken into consideration for CI surgeons to do the round
window insertion with all the possible means to get the best
benefits of cochlear implantation.
The study results recommend more future prospective studies
and systematic reviews to compare between the round
window and the cochleostomy insertion in the future to set
the round window insertion as the standard method for
electrode insertion in cochlear implantation.