Substance distribution in a cochlea model using different pump rates for cochlear implant drug delivery electrode prototypes

Paasche, Gerrit; Bögel, Lars; Leinung, Martin; Lenarz, Thomas; Stöver, Timo

doi:10.1016/j.heares.2005.10.013

Cited by 29 publications

(23 citation statements)

References 24 publications

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“…As part of it, pathways to delivery future pharmaceuticals to their site of action, e.g. the cochlear duct, are currently under investigation [Paasche et al, 2006]. Although sophisticated viral vectors might be the foundation of inner ear treatment in the future [Staecker et al, 2004], much simpler routes like topical drug application onto the cochleostomy opening during surgery -as described in this report -are currently used.…”

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confidence: 99%

Ipsilateral Electric Acoustic Stimulation of the Auditory System: Results of Long-Term Hearing Preservation

et al. 2006

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Objective: To evaluate long-term ipsilateral hearing preservation in patients who underwent cochlear implantation for the combined electric acoustic stimulation of the auditory system. Methods: This was a prospective observational study conducted at a tertiary referral center. Twenty-three subjects were implanted with the MED-EL C40+ standard or C40+ medium electrode using an atraumatic surgical protocol via an anterior-inferior cochleostomy approach. The desired insertion depth was 18–24 mm or 360°. All patients showed significant low-frequency hearing prior to surgery and monosyllabic word scores did not exceed 40% in the best aided condition. Pure-tone audiometry was performed prior to implantation and at distinct intervals after surgery. Results: Nine patients (39.1%) showed complete pure-tone audiometric hearing preservation (0–10 dB) over an average of 29 months. Seven subjects (30.4%) showed partial preservation of residual hearing (hearing loss 15–40 dB) until an average of 25 months. Delayed loss of residual hearing was observed in 5 cases (21.7%) and 2 patients (8.6%) completely lost residual hearing during or immediately after surgery. Freiburger Monosyllabic word understanding scores in a group of patients with complete hearing preservation increased from 13.1% preoperatively to 75% in the electric acoustic stimulation condition. Conclusion: This study documents that complete and partial preservation of ipsilateral hearing after cochlear implantation can be achieved in about 70% of cases over an average period of 27.25 months when using 360° electrode insertions.

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confidence: 99%

Ipsilateral Electric Acoustic Stimulation of the Auditory System: Results of Long-Term Hearing Preservation

et al. 2006

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“…The applicability of this device to the human cochlea was evaluated in vitro using samples of human temporal bone [37]. Passche et al [55] compared dye delivery in three different electrode prototypes with openings at various position along the electrode array using an in vitro plastic cochlear model, i.e. release of dye at the tip; release of the dye at the tip and the side of the electrode; and release of the dye only at the side of the electrode (Fig.…”

Section: Integrated Microfabricated Systemsmentioning

confidence: 99%

Controlled delivery for neuro-bionic devices

Yue

Moulton

Cook

et al. 2013

Advanced Drug Delivery Reviews

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Implantable electrodes interface with the human body for a range of therapeutic as well as diagnostic applications. Here we provide an overview of controlled delivery strategies used in neuro-bionics. Controlled delivery of bioactive molecules has been used to minimise reactive cellular and tissue responses and/or promote nerve preservation and neurite outgrowth toward the implanted electrode. These effects are integral to establishing a chronically stable and effective electrode-neural communication. Drug-eluting bioactive coatings, organic conductive polymers, or integrated microfabricated drug delivery channels are strategies commonly used.

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“…In none of these studies was the concentration of substance achieved in the perilymph reported. Substance distribution has been quantified in plastic models with dimensions approximating the human ST (Paasche et al, 2006). In some studies delivering drugs through cochleostomies, substantial damage to hearing at frequencies near the cochleostomy site was reported (Carvalho and Lalwani, 1999) while minimal functional losses have been found with other direct injection techniques (Chen et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Marker retention in the cochlea following injections through the round window membrane

et al. 2007

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Local delivery of drugs to the inner ear is increasingly being used in both clinical and experimental studies. Although direct injection of drugs into perilymph appears to be the most promising way of administering drugs quantitatively, no studies have yet demonstrated the pharmacokinetics in perilymph following direct injections. In this study, we have investigated the retention of substance in perilymph following a single injection into the basal turn of scala tympani (ST). The substance injected was a marker, trimethylphenylammonium (TMPA) that can be detected in low concentrations with ion-selective microelectrodes. Perilymph pharmacokinetics of TMPA was assessed using sequential apical sampling to obtain perilymph for analysis. The amount of TMPA retained in perilymph was compared for different injection and sampling protocols. TMPA concentrations measured in fluid samples were close to those predicted by simulations when the injection pipette was sealed into the bony wall of ST but were systematically lower when the injection pipette was inserted through the round window membrane (RWM). In the latter condition it was estimated that over 60% of the injected TMPA was lost due to leakage of perilymph around the injection pipette at a rate estimated to be 0.09 μL/min. The effects of leakage during and after injections through the RWM were dramatically reduced when the round window niche was filled with 1% sodium hyaluronate gel before penetrating the RWM with the injection pipette. The findings demonstrate that in order to perform quantitative drug injections into perilymph, even small rates of fluid leakage at the injection site must be controlled.

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Substance distribution in a cochlea model using different pump rates for cochlear implant drug delivery electrode prototypes

Cited by 29 publications

References 24 publications

Ipsilateral Electric Acoustic Stimulation of the Auditory System: Results of Long-Term Hearing Preservation

Ipsilateral Electric Acoustic Stimulation of the Auditory System: Results of Long-Term Hearing Preservation

Controlled delivery for neuro-bionic devices

Marker retention in the cochlea following injections through the round window membrane

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