Experimental erbium laser surgery in the guinea pig cochlea: its use in the study of afferent cochlear neurotransmitters

Arnold, A.; Felix, Dominik; Ehrenberger, K.; Frenz, Martin; Pratisto, Hans Surya; Weber, H. P.; Altermatt, H. J.

doi:10.1007/bf00179950

Cited by 10 publications

(14 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The fact that it was possible to block enhanced activity with the specific reversible agonists during distribution was an important indication that the transition of the afferent inner hair cells still worked. The influence and function of AMPA, NMDA, CNQX and AP-7 on the transition of the afferent inner hair cells is well known (22,24,25,28).…”

Section: Discussionmentioning

confidence: 99%

“…This test revealed no change in inner hair cell functionality. With specific reversible antagonists for the two receptors, CNQX for AMPA and AP-7 for NMDA, the functionality of the synaptic transition could be shown during enhanced activity (28), and is indicated by the coincidence of the activity to 4 s -1 after their application (Minutes 13 and 18). The cut off in the middle and lower traces in Fig.…”

Section: Electrophysiological Evaluationsmentioning

confidence: 99%

See 1 more Smart Citation

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

et al. 1997

Self Cite

View full text Add to dashboard Cite

Abstract. Erbium-YSGG laser systems are promising tools in ear, nose and throat (ENT) surgery. The high absorption in biological tissues, resulting in precise tissue ablation with minimal thermal tissue damage, and the possibility to guide the radiation through optical fibres make the 2.79 ~m wavelength a favourite for microsurgery.In order to simulate the fenestration of the human stapes foot plate required for prosthesis implantation when treating otosclerosis, five guinea pig cochleae were irradiated in vivo until perforation was achieved. The laser-induced temperature rise and pressure transients evoke activity in the inner hair cells that was investigated by micro-iontophoresis.Perforation of the cochlea bone (hole diameter of 350/~m) can be performed with a few laser pulses and high precision with a thermal damage zone of <100~m. The bone ablation rate is 10 + 2 ~m pulse -1 at a radiant exposure of 12 J cm-2. The functionality of the afferent inner hair cells in the guinea pig cochlea was verified before and after laser treatment using glutamate receptor agonists AMPA and NMDA. For the above selected laser parameters, the induced 15-min enhanced activity was blockable with the specific reversible AMPA and NMDA antagonists CNQX and AP-7.Micro-iontophoresis confirms the reversibility of cochlea functionality after its perforation with Er-YSGG laser pulses. A limit of radiant exposure around 12 J cm -2 is found for safe fenestration. It is demonstrated that the Er-YSGG laser is a precise and safe instrument whilst still using adequate laser parameters. On the other hand, this study demonstrates the potential of uncontrollable and unintended induced damage, resulting from vapour channel formation in the perilymph, if a high laser radiant exposure is applied.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Electrophysiological Evaluationsmentioning

confidence: 99%

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

et al. 1997

Self Cite

View full text Add to dashboard Cite

show abstract

“…Iontophoresis has been used for studying the role of synaptic neurotransmitters in auditory processing (Felix and Ehrenberger, 1990;Hurley and Pollak, 1999;Kleinlogel et al, 1999). Arnold et al (1996) used microiontopheresis to apply glutamate channel agonists and antagonists to study the effects of lasers for inner and middle ear surgery. Oestreicher et al (2000) delivered NT-3, NMDA, and non-NMDA agonists by iontophoresis to the subsynaptic region of the inner hair cells to study the effects of acute administration on neuronal activity.…”

Section: Iontophoresismentioning

confidence: 99%

“…This method of drug delivery has been used extensively in research applications for the delivery of molecules to the inner ear and central auditory pathway for pharmacological, physiological, and therapeutic purposes. Typically, glass micropipettes are loaded with ionically charged solutions that contain a soluble substance such as neurotransmitters, agonists, antagonists (Arnold et al, 1996;Ostwald, 1992, 1995;Ehrenberger and Felix, 1992;Felix and Ehrenberger, 1992;Hurley and Pollak, 1999;Walsh et al, 1995), neurotrophins (Oestreicher et al, 2000), dyes, or anti-inflammatory agents. When current is applied to a metal electrode in the micropipette, small quantities of solution are expelled and drawn into the oppositely charged tissue.…”

Section: Iontophoresismentioning

confidence: 99%

Localized cell and drug delivery for auditory prostheses

et al. 2008

View full text Add to dashboard Cite

Localized cell and drug delivery to the cochlea and central auditory pathway can improve the safety and performance of implanted auditory prostheses (APs). While generally successful, these devices have a number of limitations and adverse effects including limited tonal and dynamic ranges, channel interactions, unwanted stimulation of non-auditory nerves, immune rejection, and infections including meningitis. Many of these limitations are associated with the tissue reactions to implanted auditory prosthetic devices and the gradual degeneration of the auditory system following deafness. Strategies to reduce the insertion trauma, degeneration of target neurons, fibrous and bony tissue encapsulation, and immune activation can improve the viability of tissue required for AP function as well as improve the resolution of stimulation for reduced channel interaction and improved place-pitch and level discrimination. Many pharmaceutical compounds have been identified that promote the viability of auditory tissue and prevent inflammation and infection. Cell delivery and gene therapy have provided promising results for treating hearing loss and reversing degeneration. Currently, many clinical and experimental methods can produce extremely localized and sustained drug delivery to address AP limitations. These methods provide better control over drug concentrations while eliminating the adverse effects of systemic delivery. Many of these drug delivery techniques can be integrated into modern auditory prosthetic devices to optimize the tissue response to the implanted device and reduce the risk of infection or rejection. Together, these methods and pharmaceutical agents can be used to optimize the tissue-device interface for improved AP safety and effectiveness.

show abstract

“…3). The effect of erbium laser pulses was also tested on the inner ear of the guinea pig (17). The experimental set-up allowed measurement of the postsynaptic inner hair cell receptor activity.…”

Section: Introductionmentioning

confidence: 99%

Advantages and Dangers of Erbium Laser Application in Stapedotomy

Häusler

Schär²,

Pratisto³

et al. 1999

Acta Oto-Laryngologica

View full text Add to dashboard Cite

Among different types of lasers, the erbium laser exhibits particularly favourable characteristics for ear surgery. Experiments with application of erbium laser pulses to the isolated stapes connected to an inner ear model confirmed that there was virtually no thermal effect to the inner ear liquid and that the border damage zone on the stapes footplate perforation did not exceed 5-10 microm. Erbium laser pulses, however, produce pressure waves due to the explosive ablation of tissue. Pulses of 10 to 17 J/cm2 producing pressure waves between 140 and 160 dB appear to be a limit for clinical application. With these criteria, an in-house built erbium YAG laser with a fiberoptic delivery device was used in 15 patients for stapedotomy. A special microhandpiece, where a zirconium fluoride fiber was connected to a quartz tip, was developed. In addition, three patients had stapedotomy with a commercially available Zeiss (Opmi TwinER) microscope equipped with a micromanipulator-operated erbium laser beam. One year after surgery, the air-bone gap was closed in all patients to within 20 dB between 0.5 and 3 kHz with only minor permanent bone conduction threshold losses (< 20 dB). However, we observed an immediate postoperative middle and high frequency loss of up to 75 dB on bone conduction threshold measurements 2 h after surgery, suggesting an acoustic traumatization by the erbium laser. This threshold shift recovered close to preoperative values within 6 h. These observations prompted us to discontinue the clinical use of erbium laser for stapedotomy until the problem of temporary acoustic traumatization is resolved.

show abstract

Experimental erbium laser surgery in the guinea pig cochlea: its use in the study of afferent cochlear neurotransmitters

Cited by 10 publications

References 22 publications

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

Experimental in vivo fenestration of guinea pig cochlea using 2.79 Μm laser radiation

Localized cell and drug delivery for auditory prostheses

Advantages and Dangers of Erbium Laser Application in Stapedotomy

Contact Info

Product

Resources

About