Implications of Minimizing Trauma During Conventional Cochlear Implantation

Abstract

Objective To describe the relationship between implantation-associated trauma and postoperative speech perception scores among adult and pediatric patients undergoing cochlear implantation using conventional length electrodes and minimally traumatic surgical techniques. Study Design Retrospective chart review (2002–2010). Setting Tertiary academic referral center. Patients All subjects with significant preoperative low-frequency hearing (≤70 dB HL at 250 Hz) who underwent cochlear implantation with a newer generation implant electrode (Nucleus Contour Advance, Advanced Bionics HR90K [1J and Helix], and Med El Sonata standard H array) were reviewed. Intervention(s) Preimplant and postimplant audiometric thresholds and speech recognition scores were recorded using the electronic medical record. Main Outcome Measure(s) Postimplantation pure tone threshold shifts were used as a surrogate measure for extent of intracochlear injury and correlated with postoperative speech perception scores. Results Between 2002 and 2010, 703 cochlear implant (CI) operations were performed. Data from 126 implants were included in the analysis. The mean preoperative low-frequency pure-tone average was 55.4 dB HL. Hearing preservation was observed in 55% of patients. Patients with hearing preservation were found to have significantly higher postoperative speech perception performance in the cochlear implantation-only condition than those who lost all residual hearing. Conclusion Conservation of acoustic hearing after conventional length cochlear implantation is unpredictable but remains a realistic goal. The combination of improved technology and refined surgical technique may allow for conservation of some residual hearing in more than 50% of patients. Germane to the conventional length CI recipient with substantial hearing loss, minimizing trauma allows for improved speech perception in the electric condition. These findings support the use of minimally traumatic techniques in all CI recipients, even those destined for electric-only stimulation.

Hearing Preservation After Cochlear Implantation May Improve Long-term Word Perception in the Electric-only Condition

“…While Carlson et al (7), reported significantly better word perception scores in CI recipients with preserved residual hearing, Balkany et al (8), D'Elia et al (9), and Cosetti et al (10) could not demonstrate such an effect.…”

“…The assessment of residual acoustic hearing close to the maximum output of the audiometer leads to a ceiling effect causing an underestimation of the postoperative hearing loss and an overestimation of hearing preservation rates. To take this effect into account, different hearing preservation classifications have been proposed (7)(8)(9)(10)15). The advantage of the HEARRING group hearing preservation classification system (11) is that the postoperative PTA is related to the preoperative PTA.…”

Damage to inner ear structure during cochlear implantation: Correlation between insertion force and radio-histological findings in temporal bone specimens

“…Moreover, limiting injury potentially allows for the application of future technologies, such as cellular regeneration or other novel cochlear nerve stimulation technologies (Carlson et al, 2011).…”

Correlation of Electrophysiological Properties and Hearing Preservation in Cochlear Implant Patients

“…Intracochlear trauma should be minimized during modern-day cochlear implantation surgeries (1). It has been shown that better performance of cochlear implant recipients with minimal residual hearing is correlated with minimizing cochlear trauma (2Y4).…”