The evaluation of a slim perimodiolar electrode: surgical technique in relation to intracochlear position and cochlear implant outcomes

Abstract

Purpose In cochlear implantation (CI), the two factors that are determined by the surgeon with a potential significant impact on the position of the electrode within the cochlea and the potential outcome, are the surgical technique and electrode type. The objective of this prospective study was to evaluate the position of the slim, perimodiolar electrode (SPE), and to study the influence of the SPE position on CI outcome. Methods Twenty-three consecutively implanted, adult SPE candidates were included in this prospective cohort study conducted between December 2016 and April 2019. Mean age at surgery was 59.5 years. Mean preoperative residual hearing was 92.2 dB. Intra-operative fluoroscopy and high-resolution computed tomography scans were performed to evaluate electrode position after insertion using a cochleostomy (CS) approach. Follow-up was 12 months after implantation; residual hearing (6-8 weeks) and speech perception (6-8 weeks and 12 months) were evaluated in relation to the intracochlear SPE position. Results In most patients in whom the SPE was positioned in the scala tympani residual hearing was preserved [mean absolute increase in PTA of 4.4 dB and 77.2% relative hearing preservation (RHP%)]. Translocation into the scala vestibuli occurred in 36% of the insertions, resulting in a mean absolute increase in PTA of 17.9 dB, and a RHP% of 19.2%. Participants with a translocation had poorer speech perception scores at 12-month follow-up. Conclusion Given the incidence of CS-associated translocations with the SPE and the negative effect on outcome, it is advised to insert the SPE using the (extended) round window approach.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

The Acoustic Change Complex in Response to Frequency Changes and Its Correlation to Cochlear Implant Speech Outcomes

“…Understanding the source of this variability is critical for customized rehabilitation ( Fu and Galvin, 2008 ). The variability appears to be related to a variety of potential factors including patient demographics (e.g., patient’s age, age of implantation, duration of deafness, duration of CI use, and etiology of hearing loss), cochlear abnormalities, surgical issues, electrode insertion (e.g., insertion depth and location), clinical mapping (e.g., frequency-place mismatch), device maintenance, neural status (e.g., survival of spiral ganglion neurons, and cortical neural plasticity), and higher-level cognitive functions (e.g., verbal working memory, attention, executive function, and learning processes, Blamey et al, 1992 ; Alexiades et al, 2001 ; Doucet et al, 2006 ; Finley et al, 2008 ; Reiss et al, 2008 ; Grasmeder et al, 2014 ; Jeong and Kim, 2015 ; Moberly et al, 2018 ; Berg et al, 2020 ; Heutink et al, 2020 ; Kim et al, 2021 ). With so many influencing factors, it is difficult to predict the likelihood of CI success using only demographic data ( Lachowska et al, 2014 ).…”

Intracochlear electrode array position and cochlear implant outcomes using the nucleus slim modiolar electrode and the extended round window approach: a follow-up study

“…These results are an evident improvement compared to previously reported implantations via a cochleostomy approach at our center, and generally comparable to what is reported in the literature, although studies adequately reporting on the CT-evaluated scalar position by surgical approach for the SME are still relatively scarce. The studies in which this was determined using high-resolution imaging result in a combined average translocation risk of 4.8% (22/461) [4,[18][19][20][21][22][23][24]. Of these aggregated 461 participants, 396 could be identified as having been implanted using either a RW or eRW approach and 39 as implanted using a CS approach [4,18,20,21,23,24].…”

“…The studies in which this was determined using high-resolution imaging result in a combined average translocation risk of 4.8% (22/461) [4,[18][19][20][21][22][23][24]. Of these aggregated 461 participants, 396 could be identified as having been implanted using either a RW or eRW approach and 39 as implanted using a CS approach [4,18,20,21,23,24]. The translocation risk, extrapolated from these studies, was 3% (12/396) for the eRW/RW approach and 23% (9/39) for the CS approach.…”

“…Mechanical trauma during electrode insertion can include osseous spiral lamina fracture, lateral wall or modiolar injury, basilar membrane disruption and electrode translocation from the scala tympani (ST) to the scala vestibuli (SV) [3]. In some cases, the electrode is even inserted directly into the SV due to misplacement of the cochleostomy [4]. Several studies conclude that complete placement of the active electrode within the ST is associated with better performance with the CI, compared to partial or complete SV placement [5][6][7].…”

Az elektródasor visszatekeredésének kimutatása transzimpedanciamátrix (TIM)-vizsgálattal cochlearis implantátumban

“…A cochlea középtengelyét, a modi olust szorosan ölelő atraumatikus elektródasor igen meggyőző eredménnyel bizonyítja népszerűségét, mind az elektrofiziológiai mérések során, mind az akusztikus hallás megőrzése terén nyújtott teljesítményével. A kü lönleges kialakítással bíró elektródavégpontok a töltésát adás szempontjából hatékonyabbak, mint vastagabb tár saik, mindemellett kevésbé destruktívak az elektródasor bevezetésekor, és jelenlétük sem zavarja a kialakuló hala dóhullámot a folyadéktérben [5][6][7][8][9][10][11][12]. Ugyanakkor na gyon kevés publikáció írja le az elektródasor nem megfe lelő helyzetének előfordulási gyakoriságát, pontosabban a csúcs visszatekeredését (tip foldover).…”