Long-term Hearing Preservation and Speech Perception Performance Outcomes With the Slim Modiolar Electrode

Abstract

Objective: Describe audiologic outcomes in hearing preservation (HP) cochlear implant candidates using a slim modiolar electrode (SME). Study Design: Retrospective. Setting: Tertiary referral center. Patients: Two hundred three adult cochlear implant patients with preoperative low-frequency pure-tone average (LFPTA) 80 dB HL that received the SME. Intervention: Implantation with a SME electrode. Main Outcome Measures: Primary outcome was postoperative HP, defined as LFPTA 80 dB HL. HP status was analyzed at ''early'' (activation or 3 mo) and ''long-term'' (6 or 12 mo) time frames using the patient's worst audiogram. Speech perception tests were compared between HP and non-HP cohorts. Results: Of the 203 HP candidates, the tip fold-over rate was 7.4%. The mean shifts in LFPTA at the ''early'' and ''long-term'' time points were 25.9 AE 16.2 dB HL and 29.6 AE 16.9 dB HL, respectively. Of 117 patients with preoper-ative LFPTA 60 dB HL, the early and long-term mean LFPTA shifts were 19.5 AE 12.3 dB HL and 32.6 AE 17.2 dB HL, respectively; early and long-term HP rates were 61.1% and 50.8%, respectively. For patients with preoperative LFPTA 80 dB HL, early and long-term HP rates were 45.5% and 43.7%, respectively. No significant difference was observed in postoperative speech perception performance (CNC, AzBio, HINT) at 3, 6, or 12 months between HP versus non-HP groups. Conclusions: HP is feasible using the SME. While electroacoustic stimulation was not studied in this cohort, HP provided no clear advantage in speech perception abilities in this group of patients. The current reporting standard of what constitutes HP candidacy (preoperative LFPTA 80 dB HL) should be reconsidered.

Early Hearing Preservation Outcomes Following Cochlear Implantation With New Slim Lateral Wall Electrode Using Electrocochleography

“…With a full electrode insertion and no RT-ECochG feedback, the new SLWE demonstrated a significantly worse LFPTA average shift at 3-months postoperatively when compared with other recent slim perimodiolar electrodes and lateral wall electrodes (38)(39)(40). Our previous experience with the slim perimodiolar electrode (CI532/CI632) (41) shows a LFPTA threshold shift of 19.5 AE 12.3 dB HL at 3-months postoperatively with a HP rate of 61.1% (as compared with a 57.5 AE 25.6 dB HL threshold shift and HP rate of 23.3% with the SLWE without active feedback). The experience in this study suggests that, without RT-ECochG, rates of hearing preservation are worse, as well as LFPTA threshold shifts, and speech-perception performance.…”

An optically-guided cochlear implant sheath for real-time monitoring of electrode insertion into the human cochlea

“…The position and orientation of the sheath inside the ST plays a central role in the insertion of the slim modiolar electrode. Whereas optimal sheath position almost guarantees a perfect electrode insertion, incorrect placement of the sheath can result in electrode translocation and electrode tip fold-over [13][14][15][16][17][18][19][20][21] . Both of these complications pose a high risk for structural damage leading to residual hearing loss and suboptimal CI performance [13][14][15][16][17][18][19][20][21] .…”

“…This 5.5 mm long sheath acts as a guide catheter for insertion through the round window membrane or through a surgically drilled opening in the cochlear bone (a cochleostomy), and the entire length of the sheath is inserted into the ST. Once the sheath is inserted into its final position, the electrode array is pushed out through the sheath, whereby its pre-coiled shape naturally follows the inner curvature of the cochlea. Clinical studies showed that with this design, electrode translocations could be reduced to less than 6.6% 13 – 20 . The translocations that did occur typically happened in the proximal part of the cochlea, along the insertion trajectory of the sheath 18 .…”

Precision Medicine Approach to Cochlear Implantation

“…Recently minimally invasive surgery and delicate electrode array design have allowed hearing preservation in CI surgery, although the hearing preservation rate differs according to studies [95][96][97]. A trend toward better hearing preservation in genetically diagnosed cochlear A c c e p t e d A r t i c l e implantees have been proposed, especially in patients carrying pathogenic variants of genes specifically expressed in the stereocilia of hair cells [92,98].…”