TNF-α inhibition using etanercept prevents noise-induced hearing loss by improvement of cochlear blood flow in vivo.

OBJECTIVE: Exposure to loud noise can impair cochlear microcirculation and cause noise-induced hearing loss (NIHL). TNF-α signaling has been shown to be activated in NIHL and to control spiral modiolar artery vasoconstriction that regulates cochlear microcirculation. It was the aim of this experimental study to analyse the effects of the TNF-α inhibitor etanercept on cochlear microcirculation and hearing threshold shift in NIHL in vivo. DESIGN: After assessment of normacusis using ABR, loud noise (106 dB SPL, 30 minutes) was applied on both ears in guinea pigs. Etanercept was administered systemically after loud noise exposure while control animals received a saline solution. In vivo fluorescence microscopy of strial capillaries was performed after surgical exposure of the cochlea for microcirculatory analysis. ABR measurements were derived from the contralateral ear. STUDY SAMPLE: Guinea pigs (n = 6, per group). RESULTS: Compared to controls, cochlear blood flow in strial capillary segments was significantly increased in etanercept-treated animals. Additionally, hearing threshold was preserved in animals receiving the TNF-α inhibitor in contrast to a significant threshold raising in controls. CONCLUSIONS: TNF-α inhibition using etanercept improves cochlear microcirculation and protects hearing levels after loud noise exposure and appears as a promising treatment strategy for human NIHL.

Evaluation of an electrode prototype for atraumatic cochlear implantation in hearing preservation candidates: preliminary results from a temporal bone study.

OBJECTIVES: This study aimed to evaluate an atraumatic prototype electrode carrier for cochlear implantation, the FLEX electrode. This electrode is designed to preserve hearing and to achieve a 360-degree insertion. STUDY DESIGN: A cross-sectional human temporal bone study was conducted. SETTING: Preliminarily, the prototype electrode was inserted in a scala tympani model to measure the insertion force. Thirteen human temporal bones were acquired postmortem and implanted with the new device using the round window approach. Three of them were implanted under radiologic control to demonstrate the insertion path. After embedding, the remaining 10 temporal bones were sectioned undecalcified and examined macroscopically and histologically. MAIN OUTCOME MEASURES: The insertion force was measured to determine intracochlear resistance peaks. The insertion angle was measured, and the degree of intracochlear trauma was determined. RESULTS: The round window approach caused cochlear trauma in 1 of 10 specimens. An exact 360-degree insertion was achieved in 7 of 10 specimens (mean overall insertion angle, 360 degrees). Radiologic examination and insertion force measurements revealed the smooth and atraumatic insertion. CONCLUSION: The new prototype electrode carrier is suitable for clinical application. It can be handled easily and allows atraumatic 360-degree insertion of all electrode contacts. Therefore, this electrode concept allows good coverage of the cochlea for electrical and additional acoustic stimulation.

A coated electrode carrier for cochlear implantation reduces insertion forces.

OBJECTIVES/HYPOTHESIS: To assess the insertion forces and feasibility of insertion of a prototype electrode carrier coated with a flexible and biodegradable coating developed for lubrication and drug delivery. STUDY DESIGN: Experimental study. METHODS: Eight coated and eight uncoated electrode carriers were inserted into a scala tympani model by means of an insertion device, and forces produced during insertion were determined in near real time. The maximum insertion depths and insertion angle were determined. To test the handling and operability, five coated electrode carriers were implanted into human temporal bones. Additionally, the bones were processed undecalcified and the distribution of the coating material within the cochlea evaluated. RESULTS: Insertion forces were markedly reduced in the group of coated electrode carriers for insertion depths above 15 mm. The insertions were less fitful and led to a higher maximum insertion angle. The insertion of the coated electrode carrier was feasible, and the coating material was evident up to the apical parts of the cochlea postimplantation. CONCLUSIONS: Coating of a cochlear implant electrode carrier may reduce insertion forces responsible for the surgical trauma. Loaded with active substances, the coating may help to deliver drugs to the apical parts of the cochlear where hair cells reside in patients with residual hearing.

A new electrode for residual hearing preservation in cochlear implantation: first clinical results.

CONCLUSION: A so far unattained high rate (100%) of residual hearing preservation in cochlear implantation for electric-acoustic stimulation could be achieved using sophisticated surgical techniques in combination with the MedEl Flex EAS electrode. OBJECTIVES: This study aimed to gather first audiological and surgical results from the experience gained with the new MedEl Flex EAS electrode array. PATIENTS AND METHODS: Nine patients (aged 7.62-71.32 years) with profound high frequency hearing loss were supplied with this atraumatic electrode, which was designed to preserve residual hearing despite intracochlear insertion of an electrode array. All patients were implanted by the same surgeon. RESULTS: Hearing preservation was achieved in all patients (complete preservation 44.44%) after a mean follow-up period of 9.73 months. Mean monosyllabic test scores improved from 9% correct with the hearing aid alone to 48% with the cochlear implant and to 65% in the electric-acoustic mode.