Biodegradable magnesium metal filaments placed inside biodegradable nerve conduits might provide the physical guidance support needed to improve the rate and extent of regeneration of peripheral nerves across injury gaps. In this study, we examined basic issues of magnesium metal resorption and biocompatibility by repairing sub-critical size gap injuries (6 mm) in one sciatic nerve of 24 adult male Lewis rats. Separated nerve stumps were connected with poly(caprolactone) nerve conduits, with and without magnesium filaments (0.25 mm diameter, 10 mm length), with two different conduit filler substances (saline and keratin hydrogel). At 6 weeks after implantation, magnesium degradation was examined by micro-computed tomography and histological analyses. Magnesium degradation was significantly greater when the conduits were filled with an acidic keratin hydrogel than with saline (p < 0.05). But magnesium filaments in some animals remained intact for 6 weeks. Using histological and immunocytochemical analyses, good biocompatibility of the magnesium implants was observed at 6 weeks, as shown by good development of regenerating nerve mini-fascicles and only mild inflammation in tissues even after complete degradation of the magnesium. Nerve regeneration was not interrupted by complete magnesium degradation. An initial functional evaluation, determination of size recovery of the gastrocnemius muscle, showed a slight improvement due to magnesium with the saline but not the keratin filler, compared with respective control conduits without magnesium. These results suggest that magnesium filament implants have the potential to improve repair of injured peripheral nerve defects in this rodent model.

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ORAL PRESENTATIONSat once must work better theoretically . This study is a trial to see whether addition of intratympanic steroid to systemic steroid and hyperbaric oyygen treatment works better or not.Method: Prospective randomized study in a tertiary referral hospital. Fifty-eight patients who presented with sudden hearing loss between 2008 and 2011 were enrolled into the study. Twenty patients who had received systemic steroid and hyperbaric oxygen composed group I while 38 patients who had received intratympanic steroid in addition to systemic steroid and hyperbaric oxygen composed group II.Results: Posttreatment hearing improvement was statistically significant in both groups in terms of pure tone average according to Siegel's criteria (P < .05). Treatment was successful for 55% of patients in group I and 63% in group II. Although there is an increase in success rate with the addition of intratympanic steroid, this was not statistically significant (P > .05). Regarding profound hearing loss over 90 dB, there seems a strong statistically significant difference. Treatment didn't work in group I for a total of 6 patients (0%) while addition of intratympanic steroid to the protocol yielded success for 6 patients over 12 (50%) in group II (P < .05).Conclusion: Addition of intratympanic steroids to systemic steroid and hyperbaric oxygen yielded better results, but this was not statistically significant in general. However, intratympanic steroid injection seems beneficial for patients with profound sudden hearing loss.Objective: To establish the intracellular consequences of electrical stimulation (ES) to spiral ganglion neurons (SGNs) after deafferentation. SGNs die as a result of loss of hair cells, their sole afferent input. Some histologic animal studies of chronic ES after deafening show that ES alone may improve SGN survival. Here we use a rat model to determine the effect of both low and high pulse rate ES on activation of the pro-apoptotic transcription factor Jun in deafferented SGNs in vivo.Methods: A single electrode was implanted through the round window of kanamycin-deafened rats at either postnatal day 32 (P32) or P60 for 4 hours of ES (monopolar, biphasic pulses, amplitude twice eABR threshold) at either 100 or 5000 Hz. Jun phosphorylation, a proapoptotic signaling event known to occur in apoptotic SGNs after deafening, was assayed by immunofluorescence to quantitatively assess the effect of ES on proapoptotic signaling.Results: Jun phosphorylation was reliably suppressed by 100 Hz ES in deafened cochleae of P32 rats (P = .045) but this effect was less robust when 5000 Hz ES was used. This effect was most significant in the cochlear turn just apical to the stimulating electrode and was not significant in P60 rats. Conclusion: Suppression of phospho-Jun occurs in deafferentedSGNs after only 4 hours of ES, consistent with the hypothesis that ES provides trophic support to SGNs after deafferentation. Stimulation frequency may be consequential: 100 Hz ES was significantly more effective than 5000 Hz ES i...