Cochlear implantation improves hearing and vertigo in patients after removal of vestibular schwannoma.

OBJECTIVES: With rising quality of speech perception in cochlear implant users, the indication widens. Nowadays, cochlear implantation is reasonable even in vestibular schwannoma patients. Speech perception with a cochlear implant is in these patients as promising as in patients with sensorineural hearing loss. However, the impact of cochlear implantation on vertigo and tinnitus after removal of vestibular schwannoma has not been investigated yet. METHODS: In a retrospective study, we analysed 12 patients treated with a cochlear implant after removal of vestibular schwannoma. RESULTS: In addition to a promising hearing perception - all patients reported improvement of vertigo. This improvement was also demonstrated by postural analysis. Improvement of tinnitus was achieved in 50% of the patients. CONCLUSION: Cochlear implantation seems a promising treatment for hearing loss, vertigo and even tinnitus in patients after removal of vestibular schwannoma. However, for successful cochlear implantation with adequate speech perception and improvement of vertigo and tinnitus, functional hearing nerve and intact inner ear anatomy is necessary.

Relations Between Scalar Shift and Insertion Depth in Human Cochlear Implantation.

OBJECTIVE: The intracochlear position of an electrode array may influence the outcome after cochlear implantation. The design of the electrode array can increase the risk of trauma causing penetration of the basilar membrane or shift of the electrode array into the scala vestibuli. The aim of the present study was to identify a scalar shift after implantation of two different electrode arrays developed by one manufacturer. STUDY DESIGN: Retrospective analysis. SETTING: Tertiary referral center. PATIENTS AND INTERVENTION: Cochlear implant recipients implanted between 2010 and 2014 and receiving either a mid-scala (n = 30) or a perimodiolar (n = 30) electrode array. MAIN OUTCOME MEASURE: Occurrence of scalar shift in association with the electrode type. RESULTS: Scalar shift occurred in 26.7% (8 of 30) of the patients implanted with a perimodiolar electrode array and in 6.7% (2 of 30) of the patients implanted with the mid-scala electrode array. The mean insertion depth in the patients experiencing scalar shift after implantation of the mid-scala electrode was much deeper (21.59 ±â€Š0.34 mm) when compared with the mean insertion depth of the patients with scalar shift after implantation with a perimodiolar electrode array (17.85 ±â€Š2.19 mm). There tends to be a correlation between the cochlear length and the occurrence of a scalar shift. However, the number of patients with scalar shift in the mid-scala group is rather small. CONCLUSION: Based on the presented data, more patients implanted with a perimodiolar electrode array have a scalar shift when compared with the midscalar electrode array.

Human Plasma Rich in Growth Factors Improves Survival and Neurite Outgrowth of Spiral Ganglion Neurons In Vitro.

BACKGROUND: Platelet-rich and platelet-poor plasma (PRP and PPP) are autologous preparations from peripheral blood and contain several growth factors and cytokines involved in tissue repair. Although their neuroprotective and neuroregenerative properties have been already described, little is known about their effects in the inner ear. We, therefore, examined the effects of PRP and PPP on spiral ganglion neurons (SGN) in vitro. RESULTS: For all experiments, spiral ganglia were isolated from neonatal rats and were cultured in serum-free medium. PRP from human venous blood was added to dissociated SGN. Treatment with PRP (1:10, 1:50) significantly increased the neuronal survival and the neuronal outgrowth of SGN. This effect was completely reversed by the addition of Bay 11 (nuclear factor kappa B-inhibitor) and SB203580 (p38 mitogen-activated protein kinase [p38MAPK]-inhibitor). Furthermore, PPP was used as a cell-free matrix for the attachment of spiral ganglion explants. Coating with activated PPP improved the adhesion and neurite outgrowth of spiral ganglia explants. Therefore, activated PPP is a promising alternative for poly d/l-ornithine and laminin coating due to the gelatinous composition through the activation of PPP with calcium gluconate. PRP promotes neuroprotective and neuroregenerative effects on SGN when administered in adequate concentrations. These beneficial effects seem to be depending on NF-κB and the p38MAPK pathways. CONCLUSION: Preparations from autologous whole blood (PRP and PPP, respectively) present an interesting alternative for pharmacological intervention to the inner ear since they contain a balanced and natural composition of trophic factors.

Microenvironmental support for cell delivery to the inner ear.

Transplantation of mesenchymal stromal cells (MSC) presents a promising approach not only for the replacement of lost or degenerated cells in diseased organs but also for local drug delivery. It can potentially be used to enhance the safety and efficacy of inner ear surgeries such as cochlear implantation. Options for enhancing the effects of MSC therapy include modulating cell behaviour with customized bio-matrixes or modulating their behaviour by ex vivo transfection of the cells with a variety of genes. In this study, we demonstrate that MSC delivered to the inner ear of guinea pigs or to decellularized cochleae preferentially bind to areas of high heparin concentration. This presents an opportunity for modulating cell behaviour ex vivo. We evaluated the effect of carboxymethylglucose sulfate (Cacicol®), a heparan sulfate analogue on spiral ganglion cells and MSC and demonstrated support of neuronal survival and support of stem cell proliferation.

Heat Shock Proteins in Human Perilymph: Implications for Cochlear Implantation.

OBJECTIVE: Biomarkers reflecting the etiology and pathophysiology of inner ear diseases are limited. Evaluation of proteins in the perilymph may improve our understanding of inner ear disease. Heat shock proteins (HSP) belong to a superfamily of stress proteins and promote refolding of denatured proteins. The aim of the study was to analyze HSP in human perilymph and to identify possible correlation with audiological and etiologic data. METHODS: Sampling of the perilymph was performed during cochlear implantation and vestibular schwannoma removal. Individual proteins were identified by a shot-gun proteomics approach by orbitrap mass spectrometry. Expression of HSP genes was determined in human cochlear tissue that was obtained during transcochlear surgeries. RESULTS: Ten subgroups of HSP were identified in human perilymph samples. Increased levels of HSP were detected in a higher percentage in the perilymph of patients with residual hearing when compared with patients with no residual hearing in cochlear implantation. In patients with complete preservation of residual hearing, HSP 90 is identified in a lower percentage whereas HSP 70 1A/1B and 6 was identified in all the samples. Constitutive expression of HSP family members was verified in normal cochlear tissue. CONCLUSION: The 10 HSP variants are not identified in all the perilymph samples, but in a higher proportion in patients with residual hearing compared with patients with no residual hearing. In-depth proteome analysis of perilymph samples in correlation to patients' audiogram data shows an increased concentration of HSP in patients with residual hearing. An increase in specific HSP in patients with loss of residual hearing after cochlear implantation was not observed.

Biohybrid cochlear implants in human neurosensory restoration.

BACKGROUND: The success of cochlear implantation may be further improved by minimizing implantation trauma. The physical trauma of implantation and subsequent immunological sequelae can affect residual hearing and the viability of the spiral ganglion. An ideal electrode should therefore decrease post-implantation trauma and provide support to the residual spiral ganglion population. Combining a flexible electrode with cells producing and releasing protective factors could present a potential means to achieve this. Mononuclear cells obtained from bone marrow (BM-MNC) consist of mesenchymal and hematopoietic progenitor cells. They possess the innate capacity to induce repair of traumatized tissue and to modulate immunological reactions. METHODS: Human bone marrow was obtained from the patients that received treatment with biohybrid electrodes. Autologous mononuclear cells were isolated from bone marrow (BM-MNC) by centrifugation using the Regenlab™ THT-centrifugation tubes. Isolated BM-MNC were characterised using flow cytometry. In addition, the release of cytokines was analysed and their biological effect tested on spiral ganglion neurons isolated from neonatal rats. Fibrin adhesive (Tisseal™) was used for the coating of silicone-based cochlear implant electrode arrays for human use in order to generate biohybrid electrodes. Toxicity of the fibrin adhesive and influence on insertion, as well on the cell coating, was investigated. Furthermore, biohybrid electrodes were implanted in three patients. RESULTS: Human BM-MNC release cytokines, chemokines, and growth factors that exert anti-inflammatory and neuroprotective effects. Using fibrin adhesive as a carrier for BM-MNC, a simple and effective cell coating procedure for cochlear implant electrodes was developed that can be utilised on-site in the operating room for the generation of biohybrid electrodes for intracochlear cell-based drug delivery. A safety study demonstrated the feasibility of autologous progenitor cell transplantation in humans as an adjuvant to cochlear implantation for neurosensory restoration. CONCLUSION: This is the first report of the use of autologous cell transplantation to the human inner ear. Due to the simplicity of this procedure, we hope to initiate its widespread utilization in various fields.