Cochlear Implant Electrode Insertion: The Round Window Revisited

Roland, Peter S.; Wright, Charles G.; Isaacson, Brandon

doi:10.1097/mlg.0b013e318064e891

Cited by 197 publications

(190 citation statements)

References 14 publications

(20 reference statements)

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“…It can not be fully exposed without drilling of the bony overhangs, because its size and orientation of the opening vary [10] . One study showed that drilling the niche overhangs increases the visible surface area of the membrane by a factor of 1.5 to 3 times and, on top of that, demonstrated by cadaveric temporal bone dissection that drilling of the antero-inferior margin of the round window membrane provided unrestricted access of the electrode to the scala tympani [11] .…”

Section: Discussionmentioning

confidence: 99%

“…The misplacement is thought to be due to the inadequate identification of the round window membrane. The round window varies in size and shape and so does its bony margin [10,11] . Bony overhangs or intracochlear obstructive structures can result in the misguiding of the electrode toward the basilar membrane and not along the scala tympani, as in our cases.…”

Section: Discussionmentioning

confidence: 99%

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Electrode Misdirection into the Superior Semicircular Canal: Complication of Cochlear Implantation by Round Window Approach

Kim¹,

Yang²,

Jeon³

et al. 2015

Int Adv Otol

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OBJECTIVE:The purposes of this study were to investigate the misdirection of the electrode into the superior semicircular canal during cochlear implantation and to suggest surgical principles for correct electrode insertion through the round window membrane. MATERIALS and METHODS:In this retrospective case review, operative records and postoperative images of cochlear implantations performed at a tertiary care facility from 1988 to 2010 were reviewed. RESULTS:In 3 out of 629 cases, electrode insertion into the superior semicircular canal was found. All 3 cases occurred in cochlear implantations using the round window approach, and none was found when using the cochleostomy approach. Insufficient exposure of the round window membrane and intra-cochlear soft tissue were regarded as the cause of misdirection of the electrode. The electrodes were repositioned appropriately into the cochlea with revision surgery in all 3 cases. CONCLUSION:In order to prevent electrode misdirection during cochlear implantation through the round window, the round window membrane needs to be clearly visualized by sufficiently drilling bony overhangs and removing soft tissues around the round window.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Electrode Misdirection into the Superior Semicircular Canal: Complication of Cochlear Implantation by Round Window Approach

Kim¹,

Yang²,

Jeon³

et al. 2015

Int Adv Otol

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“…Also, it is our practice to remove the bony overhang of the RW niche, because it increases the exposure of the RWM. This facilitates the usage of the St. Thomas' Hospital Classification and electrode insertion along the scala tympani lumen rather than towards the modiolus [19] .…”

Section: Comparisons With Other Studiesmentioning

confidence: 99%

Radiological Dehiscence of the Mastoid Portion of the Facial Nerve after Posterior Tympanotomy: Does It Lead to Increased Risk of Nerve Injury?

Lee¹,

Connor²,

Tysome³

et al. 2014

Int Adv Otol

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OBJECTIVE:We aimed to establish the frequency of postoperative bony dehiscence overlying the mastoid portion of the facial nerve after round window membranous cochleostomy using high-resolution computer tomography, and to ascertain whether this was associated with a higher incidence of facial nerve injury compared with other studies. We also evaluated the usefulness of the St Thomas' classification in predicting the possibility of performing round window insertions. Study Design: Retrospective case series.Setting: Tertiary auditory implant centre. MATERIALS and METHODS:Twenty-five patients who underwent cochlear implantation at our institution, two of whom were operated on bilaterally, yielding 27 ears for analysis. We conducted submillimetric analysis of postoperative high-resolution computer tomography images to ascertain the prevalence of bony dehiscence overlying the mastoid portion of the facial nerve. The type of round window found during surgery was also determined in medical records. RESULTS:We found a radiological dehiscence rate of 40%. None of the patients in our series sustained a facial palsy. We propose some possible reasons for differences between our findings and those of others. All 18 patients with a Type Ia round window, two of the three patients with a Type IIa round window, and none of the four patients with a Type III round window had a successful round window insertion. The classification was found to be a useful predictor of performing round window membranous cochleostomy. CONCLUSION:Thinning of the bony cover of mastoid potion of the facial nerve to the point of radiological dehiscence does not put it at risk. Novice cochlear implant surgeons can therefore be reassured that unroofing the bone overlying the nerve does not pose undue danger.

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“…There are two techniques to place cochlear implants: via a cochleostomy, in which the promontory is drilled to fixate the implant, or via the round window (RW). Less drilling is required in the RW technique, thus reducing trauma, loss of perilymph, and bone powder on the tympanic scale 9 . Preservation of residual hearing has been viable and beneficial due to the combination of electrical and acoustic stimulation, but it requires non-traumatic insertion of the electrode to minimize damage to inner ear structures and enable lesser neural tissue degeneration 6 .…”

Section: Introductionmentioning

confidence: 99%

Comparação da telemetria de resposta neural via cocleostomia ou via janela redonda no implante coclear

Hamerschmidt¹,

Schuch²,

Rezende³

et al. 2012

Braz. j. otorhinolaryngol.

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There are two techniques for cochlear implant (CI) electrode placement: cochleostomy and the round window (RW) approach.Objective: This study aims to compare neural response telemetry (NRT) results immediately after surgery to check for possible differences on auditory nerve stimulation between these two techniques. Materials and Methods:This is a prospective cross-sectional study. Twenty-three patients were enrolled. Six patients underwent surgery by cochleostomy and 17 had it through the RW approach.Results: Mean charge units (MCU) for high frequency sounds: patients submitted to the RW approach had a mean value of 190.4 (± 29.2) while cochleostomy patients averaged 187.8 (± 32.7); p = 0.71. MCU for mid frequency sounds: patients submitted to the RW approach had a mean value of 192.5 (± 22) while cochleostomy patients averaged 178.5 (± 18.5); p = 0.23. MCU for low frequency sounds: patients submitted to the RW approach had a mean value of 183.3 (± 25) while cochleostomy patients averaged 163.8 (± 19.3); p = 0.19. Conclusion:This study showed no differences in the action potential of the distal portion of the auditory nerve in patients with multichannel cochlear implants submitted to surgery by cochleostomy or through the RW approach, using the implant itself to generate stimuli and record responses. Both techniques equally stimulate the cochlear nerve. Therefore, the choice of approach can be made based on the surgeon's own preference and experience. Braz J Otorhinolaryngol. 2012;78(4):71-5. ORIGINAL ARTICLE BJORL

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Cochlear Implant Electrode Insertion: The Round Window Revisited

Abstract: RW insertion can be performed in a manner that is potentially less traumatic than the standard cochleostomy insertion. It may therefore be advantageous in cases in which hearing preservation is the goal.

Cited by 197 publications

References 14 publications

Electrode Misdirection into the Superior Semicircular Canal: Complication of Cochlear Implantation by Round Window Approach

Electrode Misdirection into the Superior Semicircular Canal: Complication of Cochlear Implantation by Round Window Approach

Radiological Dehiscence of the Mastoid Portion of the Facial Nerve after Posterior Tympanotomy: Does It Lead to Increased Risk of Nerve Injury?

Comparação da telemetria de resposta neural via cocleostomia ou via janela redonda no implante coclear

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