No abstract available.
Fistula* ; Perilymph*

No abstract available.
Perilymph* ; Sodium Salicylate* ; Sodium*

No abstract available.
Animals ; Guinea Pigs* ; Guinea* ; Perilymph*

Perilymph fistula (PLF) is a disease for which diagnostic criteria have not been established yet. For this reason, at the present time, the definitive diagnosis of PIS can only be made by direct identification of perilymphatic leak during exploratory tympanotomy. But it can be difficult to distinguish between serous transudates from operative incisions and the clear fluid expected with a true fistula. Infiltrated lidocaine makes the distinction even more difficult as well. Recently, endoscopies have been used in middle ear by transtympanic or transtubal approach. However, endoscopic diagnosis of PLF in the literature is very rare. We diagnosed 2 cases of PLF by transtympanic endoscopy. Because transtympanic endoscopy did not require lidocaine infiltration nor performing a tympanomeatal flap, confirmation of perilymphatic leakage was easier. This study therefore recommends transtympanic endoscopy as one method of improving diagnosis of PLF.
Diagnosis* ; Ear, Middle ; Endoscopy ; Exudates and Transudates ; Fistula* ; Lidocaine ; Perilymph*

OBJECTIVES: Treatment of traumatic perilymph fistula (PLF) remains controversial between surgical repair and conservative therapy. The aim of this study is to analyze the outcomes of early surgical exploration in suspected barotraumatic PLF. METHODS: Nine patients (10 cases) who developed sudden sensorineural hearing loss and dizziness following barotrauma and underwent surgical exploration with the clinical impression of PLF were enrolled. Types of antecedent trauma, operative findings, control of dizziness after surgery, postoperative hearing outcomes, and relations to the time interval between traumatic event and surgery were assessed retrospectively. RESULTS: All patients had sudden or progressive hearing loss and dizziness following trauma. Types of barotrauma were classified by the origin of the trauma: 4 external (car accident, slap injury) and 6 internal traumas (lifting, nasal blowing, straining). Surgical exploration was performed whenever PLF was suspected with the time interval of 2 to 47 days after the trauma. The possible evidence of PLF was found during surgery in 9 cases: a fibrous web around the oval window (n=3), fluid collection in the round window (RW; n=6) and bulging of the RW pseudomembrane (n=1). In every patient, vestibular symptoms disappeared immediately after surgery. The hearing was improved with a mean gain of 27.0+/-14.9 dB. When the surgical exploration was performed as early as less than 10 days after the trauma, serviceable hearing (< or =40 dB) was obtained in 4 out of 7 cases (57.1%). CONCLUSION: Sudden or progressive sensorineural hearing loss accompanied by dizziness following barotrauma should prompt consideration of PLF. Early surgical exploration is recommended to improve hearing and vestibular symptoms.
Barotrauma ; Dizziness ; Fistula ; Hearing ; Hearing Loss ; Hearing Loss, Sensorineural ; Humans ; Perilymph

While systemic steroid therapy is most widely considered as a main treatment for idiopathic sudden sensorineural hearing loss (SSHL), the disadvantages of its use are numerous side effects. Intratympanic steroid injection (ITS) delivers steroids through transtympanic route, hence avoids possible side effects with higher perilymph concentration. We conducted a reviewed 47 clinical studies after an online search of the PubMed databases for the following terms "sudden hearing loss, intratympanic steroid". Although the study settings are varied among reviewed articles, most studies in this review consistently showed some benefit of hearing in salvage cases. In addition, it is suggested that intratympanic steroids are equivalent to systemic steroid therapy as initial treatment for SSHL. In patients with contraindications against the use of systemic steroid, ITS may be considered as valuable option for primary therapy. Further studies are necessary to elucidate the optimal protocol of administration.
Hearing ; Hearing Loss ; Hearing Loss, Sensorineural ; Hearing Loss, Sudden ; Humans ; Perilymph ; Steroids

While systemic steroid therapy is most widely considered as a main treatment for idiopathic sudden sensorineural hearing loss (SSHL), the disadvantages of its use are numerous side effects. Intratympanic steroid injection (ITS) delivers steroids through transtympanic route, hence avoids possible side effects with higher perilymph concentration. We conducted a reviewed 47 clinical studies after an online search of the PubMed databases for the following terms "sudden hearing loss, intratympanic steroid". Although the study settings are varied among reviewed articles, most studies in this review consistently showed some benefit of hearing in salvage cases. In addition, it is suggested that intratympanic steroids are equivalent to systemic steroid therapy as initial treatment for SSHL. In patients with contraindications against the use of systemic steroid, ITS may be considered as valuable option for primary therapy. Further studies are necessary to elucidate the optimal protocol of administration.
Hearing ; Hearing Loss ; Hearing Loss, Sensorineural ; Hearing Loss, Sudden ; Humans ; Perilymph ; Steroids

OBJECTIVETo determine pharmacokinetics profiles of methylprednisolone (MTH) in perilymph and plasma of guinea pig after intratympanic injection of MTH in different concentrations.

METHODSBy auripuncture, three different concentrations of MTH were used in guinea pigs: 32.0 mg/ml, 40.0mg/ml and 62.5 mg/ml. Samples of plasma and perilymph of the scala tympani were collected at 1-12 h after administration and the concentrations of MTH were assayed using high-performance liquid chromatography. Auditory brainstem response (ABR) was detected before and 12h after MTH administration.

RESULTSThe concentrations of MTH in perilymph were dose-related. The differences of MTH concentrations in perilymph before and at series sampling time after administration were significant in statistics (P < 0.05), except for the intervals of 5 h, 6 h and 12 h. In addition, the concentration of MTH in perilymph was the highest in 62.5 mg/ml group. No MTH was detected in plasma after local administration, except for 1.5 h and 2 h after administration with 62.5 mg/ml. There were not differences in the thresholds of wave III of ABR before and 12h after local MTH administration among three groups (P > 0.05).

CONCLUSIONSThe experimental results indicates that the concentration of 62.5 mg/ml of MTH is optimal for treatment inner ear diseases by intratympanic administration among three groups, it get a high concentration in perilymph and not effect on the function of inner ear.

Administration, Topical ; Animals ; Guinea Pigs ; Methylprednisolone ; administration & dosage ; pharmacokinetics ; Perilymph ; chemistry ; Plasma ; chemistry

OBJECTIVETo study the pharmacokinetics of lipoic acid in guinea pig perilymph and to provide experimental evidence for clinical delivery methods and dose in order to compare of intravenous and intratympanic administration using high-performance liquid chromatography (HPLC).

METHODSFifty-four guinea pigs were randomly divided into two groups of intratympanic and intravenous administration, with 27 ones in each group, and the concentration of lipoic acid was 100 mg/ml. The concentration of lipoic acid in perilymph was detected respectively by HPLC at 0.5, 1, 2, 3, 4, 5, 6, 8 and 10 h after administration.

RESULTSA well linear relation of concentration of lipoic acid in perilymph was shown when the concentration was detected from 0.1 to 200 microg/ml (r(2) = 0.9996). The maximum of concentration of lipoic acid administrated via intratympanic was 171.7 microg/ml, and via intravenous was 33.7 microg/ml; the MRT of intratympanic injection was 3.7 h while intravenous injection was 2.9 h; the half life (t(1/2)) of the former was 1.8 h but the latter was 2.1 h.

CONCLUSIONSThe drug concentration could both be detected via intravenous and intratympanic injection in perilymph of guinea pig, But the effect of local administration via intratympanic was obvious superior to systemic administration.

Animals ; Antioxidants ; Dexamethasone ; administration & dosage ; Ear, Inner ; Guinea Pigs ; Perilymph ; Thioctic Acid

OBJECTIVES: Lidocaine is one of the therapeutic trials to treat tinnitus. However, the exact mechanism of the effect of lidocaine remains unclear. The aim of this study was to elucidate the action site of lidocaine in the cochlea by measuring compound action potential (CAP) and transient evoked otoacoustic emission (TEOAE) amplitude in guinea pigs. METHOD: Artificial perilymph was perfused into the scala tympani of the guinea pig cochlea in the control group, and lidocaine diluted with artificial perilymph was perfused into the scala tympani of the experimental groups. Electrocochleogram (ECoG) and TEOAE were measured in each groups both before and after lidocaine perfusion. RESULTS: Artificial perilymph perfused to the scala tympani of the guinea pig cochleae did not affect either the CAP threshold or the TEOAE response. But, lidocaine perfused into the scala tympani of the guinea pig cochleae produced a dose-dependent increase in CAP threshold, but did not affect TEOAE response. CONCLUSION: This study revealed that lidocaine perfused into the scala tympani of the guinea pig cochlea affects the CAPthreshold but not the TEOAE amplitude and reproducibility. It means that the locally perfused lidocaine affects the cochlear nerve greater than the outer hair cells.
Action Potentials ; Animals ; Cochlea* ; Cochlear Nerve ; Guinea Pigs* ; Guinea* ; Hair ; Lidocaine* ; Perfusion ; Perilymph ; Scala Tympani ; Tinnitus