Fístula perilinfática de causa traumática. Reporte de un caso pediátrico / Traumatic perilymphatic fistula. Report of a pediatric case

La fístula perilinfática de causa traumática es una patología poco habitual. En general, es causada por lápices, hisopos, hebillas de pelo y fósforos.Dentro de los síntomas más frecuentes, los pacientes pueden presentar hipoacusia y vértigo. Su diagnóstico requiere un examen físico completo que incluya otomicroscopía, audiometría ytomografía computada de ambos peñascos. El tratamiento depende de la sintomatología del paciente. En general, en un principio, es conservador, pero puede llegar a requerir cirugía. Se presenta un caso clínico de un niño de 6 años con fístula perilinfática secundaria a un traumatismo del oído izquierdo por un hisopo, que requirió tratamiento quirúrgico

Traumatic perilymphatic fistula is an unusual pathology. Generally caused by pencils, swabs, hair buckles, and matches. Among the most frequent symptoms, patients can present hearing loss and vertigo.Diagnosis requires a complete physical examination that includes otomicroscopy, audiometry and computed tomography of both boulders. Treatment depends on the patient's symptoms. In general, it is conservative at first, but may require surgery.We present a clinical case of a 6-year-old boy with perilymphatic fistula secondary to left ear trauma due to swab, which required surgical treatment

Safety and Effectiveness of Endoscopic Ear Surgery: Systematic Review / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: This study aims to evaluate that usefulness of the endoscopic ear surgery (EES) through the systematic review. SUBJECTS AND METHOD: We searched literatures in literature databases (MEDLINE, EMBASE, Cochrane Library, etc.). Inclusion criteria is 1) studies of patients with chronic otitis media, otitis media with effusion, cholesteatoma, conductive hearing loss, mixed hearing loss etc. 2) studies in which a transcanal endoscopic surgery was performed; and 3) studies in which one or more of the appropriate medical outcomes have been reported. We excluded that 1) non-human studies and pre-clinical studies; 2) non-original articles, for example, non-systematic reviews; editorial, letter and opinion pieces; 3) research not published in Korean and English; and 4) grey literature. Finally, 65 articles were selected and those results were analyzed. RESULTS: The safety of the EES was reported in 61 articles. Some studies reported damaged facial nerve or perilymph gusher but these are the complications that can arise due to the characteristics of the disease and not due to the EES and other reported complications were of similar or lower level in the intervention group rather than the microscopy group. The effectiveness of the EES was reported in 23 articles. The EES tended to show improved effects in terms of graft uptake status, cholesteatoma removal, and hearing improvement although effective outcomes of most studies reported no significant difference between EES and microscopic ear surgery. CONCLUSION: EES is a safe and effective technique and as it is less invasive than the microscopic ear surgery.

A Case of Sensorineural Hearing Loss and Vertigo during Epidural Nerve Block / 대한평형의학회지

Epidural anesthesia has significantly advanced in neuraxial anesthesia and analgesia. It is used for surgical anaesthesia and treatment of chronic pain. Hearing loss during or after epidural anesthesia is rare, and it is known to occur by the change of the intracranial pressure. Cerebrospinal fluid is connected with perilymph in the cochlear and vestibule that is important to hearing and balance. If the intracranial pressure is abruptly transferred to the inner ear, perilymph can be leak, that called perilymphatic fistula, dizziness, and hearing loss can occur suddenly. We report a 65-year-old woman who presented with acute onset dizziness and hearing loss during the epidural nerve block for back pain, wherein we speculated a possibility of perilymphatic fistula as the mechanism of hearing loss and dizziness. The mechanism of dizziness and hearing loss was suspected with perilymphatic fistula.

Measurement of the Mechanical Deformation of Organ of Corti in a Model of Acute Endolymphatic Hydrops / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Endolymphatic hydrops has been considered as an important histologic substrate of Meniere's disease. A permanent displacement of basilar membrane (BM) by increased endolymphatic pressure has been thought to be an explanation for hearing change. Direct observation of histological sections of temporal bones, however, suggested that stereocilia and tectorial membrane decoupling is more associated with pressure induced by mechanical deformation of the organ of Corti rather than with the displacement of BM. METERIALS AND METHOD: 26 cochleae from 13 female pigmented ginea pigs were harvested. One cochlea per each animal was injected with artificial perilymph. The other one was used as control. After fixation, followed by embedding and mid-modiolar sectionning, specimens were observed with a microscope. Morphometric parameters of each row and turn of the organ of Corti were measured and quantified. RESULTS: The average area and height of the organ of Corti were significantly smaller in the apical turn of the experimental group (p<0.05). The lengths of outer hair cell and Deiters cell in the apical turn were also significantly reduced in the experimental group (p<0.05). The angle between the outer hair cell and Deiters cell was smaller in the apex and in the 3rd turn of the experimental group (p<0.05). CONCLUSION: Results show that compression and deformation of the organ of Corti, especially in the apical turn, is a prominent feature in the acute endolymphatic hydrops model. We suggest that the deformation of organ of Corti is the primary cause of hydrops that induce the decoupling of tectorial membrane and stereocilia rather than the displacement of BM.

A Case of Perilymphatic Fistula Misdiagnosed as Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

Perilymphatic fistula (PLF) is an uncommon disease characterized by abnormal leakage of the perilymph from the inner ear into the middle ear. The symptoms of PLF include sudden-onset hearing loss, tinnitus, ear fullness, and vertigo resulting from inner-ear trauma, stapedial surgery or barotrauma such as valsalva, and nose blowing. As nystagmus can be induced by the affected-ear in down position, benign positional paroxysmal vertigo (BPPV) should be considered for differential diagnosis. About 40-50% of PLF patients have experienced spontaneous healing, but surgical repair should be considered when the hearing symptom and dizziness are not alleviated or are aggravated within a few days. Reported herein, with a review of the relevant literature, is a case of PLF initially misdiagnosed as BPPV but where successful fistula repair was finally achieved.

Critical Evaluation of Round Window Membrane Sealing in the Treatment of Idiopathic Sudden Unilateral Hearing Loss

OBJECTIVES: Rupture of the round window membrane with consecutive development of a perilymphatic fistula (PLF) is still a matter of controversial debate in the pathogenesis of idiopathic sudden sensorineural hearing loss (SSHL). Until now no consensus exists about whether these patients benefit from performing an exploratory tympanotomy with sealing of the round window. The aim of the present study was to analyze critically the effectiveness of sealing the round window membrane in patients with SSHL. METHODS: The clinical data of 51 patients with SSHL and a mean hearing decline of at least 60 dB over 5 frequencies who were treated with tympanotomy and sealing of the round window membrane were retrospectively analyzed. The results have been compared to the current state of the literature. RESULTS: Intraoperatively a round window membrane rupture or fluid leak was observed in none of the patients. After performing tympanotomy the mean improvement of hearing level was 32.7 dB. Twenty of 51 examined patients (39.2%) showed a mean improvement of the hearing level of more than 30 dB and a complete remission could be detected in 12 patients (23.5%). Reviewing the literature revealed no standard guidelines for definition or treatment of SSHL as well as for evaluation of hearing loss and its recovery. CONCLUSION: The results of the present study and the literature should be discussed critically. It is unclear whether tympanotomy and sealing of the round window membrane may be a meaningful treatment for SSHL. Therefore this procedure should be discussed as a therapeutic option only in selected patients with sudden deafness or profound hearing loss in which PLF is strongly suspicious or conservative treatment failed.

Two Cases of Barotraumatic Perilymph Fistula Mimicking Atypical Benign Paroxysmal Positional Vertigo with Sudden Hearing Loss / 대한평형의학회지

Barotraumatic perilymph fistula is difficult to diagnose and needs diagnosis of suspicion. Symptoms like hearing loss, tinnitus, ear fullness and positional dizziness can develop following barotrauma such as valsalva, nose blowing, straining and diving, etc. We reported 2 cases of perilymph fistula following barotrauma. The patients developed hearing loss, tinnitus and ear fullness followed by sudden onset of positional dizziness mimicking benign paroxysmal positional vertigo (BPPV). On positional tests, the direction of nystagmus has changed over time. In addition, the characteristics of nystagmus on positional test were not similar to typical BPPV, which showed longer duration of nystagmus, no reversibility and no fatigability. We concluded that barotraumatic perilymph fistula could present as hearing loss with positional dizziness mimicking sudden hearing loss with BPPV. The differential diagnostic points were history of barotrauma, time sequence of development of hearing loss and positional dizziness, and atypical positional nystagmus unlike BPPV.

Isosorbide Concentration in Perilymph of the Guinea Pig After Oral Administration Versus That After Round Window Perfusion

OBJECTIVES: The aims of this study were to investigate the feasibility of isosorbide delivery into perilymph through the round window membrane (RWM), and to compare the intracochlear isosorbide concentration in perilymph after oral administration (PO) versus that after round window perfusion (RWP). METHODS: Sixteen male guinea pigs (32 ears) were used. Isosorbide, an osmotic diuretic, was administered via RWP or PO. First, to investigate the optimal perfusion time, perilymph sampling of scala tympani from the RWM was performed after RWP for 15, 30, or 60 minutes. Second, to compare the drug concentration after RWP versus that after PO, perilymph was aspirated at 3 and 6 hours after administration. Intracochlear concentration of isosorbide was analyzed by high-performance liquid chromatography coupled to refractive index detection. RESULTS: Isosorbide passed through the RWM into perilymph after RWP. After RWP for 15, 30, and 60 minutes, mean isosorbide concentrations in perilymph were 116.27+/-44.65, 245.48+/-112.84, and 279.78+/-186.32 mM, respectively. The intracochlear concentration after RWP for 30 minutes was higher than that after RWP for 15 minutes (P=0.043). At 3 and 6 hours after PO, isosorbide concentrations in perilymph were 28.88+/-4.69 and 12.67+/-2.28 mM, respectively. In contrast, the corresponding concentrations after RWP were 117.91+/-17.70 and 75.03+/-14.82 mM at 3 and 6 hours, respectively. Isosorbide concentrations in perilymph following RWP were significantly higher than those following PO at both 3 and 6 hours (P=0.025 and P=0.034, respectively). CONCLUSION: Isosorbide can rapidly pass through the RWM after RWP in guinea pigs, and 30 minutes of perfusion is considered to be appropriate. In addition, over a 6-hour period, RWP can deliver higher concentrations of isosorbide into perilymph than those achieved with PO.

A Case of Intractable Suspected Perilymph Fistula with Severe Depression

A 68-year-old woman presented dizziness whenever she put her finger into the right ear and also complained of water-streaming tinnitus, which indicated she would have been suffering from perilymph fistula. An exploratory tympanotomy was conducted. Leakage of perilymph from the round window was suspected, although the cochlin-tomoprotein (CTP) results were negative. After the procedure, the patient's finger-induced dizziness, tinnitus, and vertigo spells disappeared completely. However, her dizzy symptom did not improve. The patient also complained of general fatigue, weight loss, and insomnia, which led us to suspect comorbid depression. Antidepressants and vestibular rehabilitation treatment resulted in a significant improvement in her dizziness. Although it is not apparent whether the patient had a perilymph fistula, this case demonstrates the importance of evaluating not only physical symptoms but also psychological comorbidity, especially when the physical symptoms are intractable despite treatment.

Visualization of endolymphatic hydrops in 3D-FLAIR MRI after intratympanic Gd-DTPA administration in Meniere's disease patients / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the feasibility of endolymphatic visualization and the diagnosis of Meniere's disease by applying intratympanic gadolinium administration through the tympanic membrance and three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI). To study the relationship between the endolymphatic hydrops visualized by MRI and audio-vestibular functional tests, such as pure tone audiometry (PTA), electrocochleography (EcoG), caloric test and vestibular evoked myogenic potential (VEMP).</p><p><b>METHODS</b>With a three Tesla magnetic resonance imaging (MRI) unit, 3D-FLAIR imaging was performed 24 hours after intratympanic gadolinium through the tympanic membrance in 32 patients with clinically diagnosed unilateral Meniere's Disease. We visualized the enhanced imaging of perilymphatic space in bilateral cochlea, vestibular and (or) canal, scoring scala tympani and scala vestibule of bilateral cochlear basal turn respectively and measuring the developing area of bilateral vestibule and the signal intensity ratio (SIR) between the vestibule and the brain stem subjectively. PTA, EcoG, caloric test and VEMP were performed. The relationship between the endolymphatic hydrops visualized by MRI and audio-vestibular functional tests were studied.</p><p><b>RESULTS</b>The gadolinium appeared in almost all parts of the perilymph in cochlea, vestibular and (or) canals in all 32 patients' inner ears, so the endolymphatic space was clearly shown on 3D-FLAIR imaging. The scala vestibuli score value between the affected side and the healthy side were statistically significant (Z = 4.309, P < 0.05) . The developing vestibular area between the affected side and the healthy side [(6.04 ± 2.89) mm(2), (8.28 ± 3.04)mm(2)] were statistically significant (t = 3.322, P < 0.05) . Abnormal vestibular evoked myogenic potentials were significantly correlated with the developing vestibular area of the affected side (F = 11.96, P < 0.05) . Abnormal electrocochleography were significantly correlated with scala vestibuli score value of cochlear basal turn in the affected side (Z = 3.17, P < 0.05) . No significant correlation was found between the scala vestibuli score value or the developing vestibular area and caloric test or PTA findings.</p><p><b>CONCLUSIONS</b>3D-FLAIR MRI with intratympanic gadolinium injection through the tympanic membrance can discriminate the border between the perilymph and the endolymph and show endolymphatic hydrops. This method may provide radiographic reference for the diagnosis of Meniere's disease. The results of VEMP and electrocochleography might have appropriate correlation with degree of vestibular and cochlear hydrops.</p>

Math1 gene therapy for kanamycin and furosemide-induced deaf guinea pigs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To observe the morphology and function changes of cochlear hair cells before and after math1 gene injection into the cochlea of deaf guinea pigs which were induced by kanamycin and furosemide. To explore the feasibility of Math1 gene for medicine-induced deafness therapy.</p><p><b>METHODS</b>Kanamycin (500 mg/kg) and furosemide (50 mg/kg) were given to the healthy adult guinea pigs intramuscularly and intravenously to establish the deafness model. The guinea pigs whose auditory brainstem response (ABR) threshold > 95 dB SPL were randomly divided into five groups. Blank control group (without any treatment, n = 3), operation control group (right ear scala tympani operation, n = 3), artificial perilymph group (right ear scala tympani injection artificial perilymph, n = 3), virus vector group [right ear scala tympani injection adenovirus which carrying enhanced green fluorescent protein (EGFP) gene (Ad. EGFP) , n = 4], Math1 gene therapy group [right ear scala tympani injection adenovirus which carrying Math1 and EGFP gene (Ad. Math1-EGFP), n = 6]. Each animal received ABR test before and after injection. The cochlear tissue was observed by scanning electronic microscopy.</p><p><b>RESULTS</b>The ABR thresholds of tone burst( 4, 8, 16, 20 kHz ) were not statistically significant in different groups (P > 0.05). The number of hair cells increased in some of severe deaf guinea pigs after the injection of Ad. Math1-EGFP gene. However, there was no obvious difference with morphology and numbers of cochlea hair cells in other groups.</p><p><b>CONCLUSIONS</b>The injection of Math1 gene to cochlea can regenerate or repair the hair cells of medicine-induced deaf guinea pigs, but there was no improvement on the hearing loss.</p>

Effects of Early Surgical Exploration in Suspected Barotraumatic Perilymph Fistulas

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.

The Effect of Ginkgo Biloba on the Survival of Spiral Ganglion Neurons in Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Ginkgo biloba extract (GBE) enhances cell survival in various organs. GBE protects nerve cells in the central nervous system and is clinically applied in Parkinson's and Alzheimer's disease. GBE can protect ototoxicity caused by cisplantin and gentamycin through rescue of hair cells in Organ of Corti and is accepted as one of the therapeutic agents for sudden deafness and tinnitus. The experimental study on GBE for the inner ear is confined to the hair cells, not to the spiral ganglion neurons (SGNs) which is the stimulated part by the electrode of cochlear implant. The aim of this study is to elucidate the effect of GBE on the survival of SGNs after hair cell loss in rats. MATERIALS AND METHOD: Ten Sprague-Dawley rats aged 50 days (P50) were deafened with kanamycin sulfate. GBE (EGb 761) was injected into the right cochlea and artificial perilymph was injected into the left side. The number and size of SGNs were compared after immunohistochemical statin in both groups. The expression of pJun, which is well-known as a proapoptotic transcription factor in the cochlea, was also compared. RESULTS: The number of SGNs was significantly larger in the GBE group than the control. The expression of pJun activity was significantly decreased in GBE group than the control. The size of SGNs in both groups was similar. CONCLUSION: These results suggest that GBE can protect SGNs death by inhibiting the pJun-C-jun N-terminal kinase pathway. GBE might be a potential drug for the patients with total deafness before or after cochlear implantation surgery for better hearing results.

Intratympanic Steroid Therapy for Sudden Sensorineural Hearing Loss

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.

Intratympanic Steroid Therapy for Sudden Sensorineural Hearing Loss

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.

In vivo distribution and pharmacokinetics of multiple effective components contained in Panax notoginseng saponins after intratympanic administration / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate in vivo distribution and pharmacokinetics of ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1 ) and sanchinoside R1 (R1) after intratympanic administration (IT) or intravenous administration (IV) of Panax notoginseng saponions (PNS) solution, and provide a novel route for delivering traditional Chinese medicine (TCM) to the brain.</p><p><b>METHOD</b>The guinea pigs were employed as experimental animal. Perilymph (PL), cerebrospinal fluid (CSF), brain tissue and plasma were collected periodically after IT and IV of PNS solution. The concentrations of Rb1, Rg1 and R1 were measured by high performance liquid chromatography (HPLC), and statistic program DAS was applied to the calculation of pharmacokinetic parameters. The self-defined weighting coefficients based on area under curve (AUC) of each component were created to obtain the holistic pharmacokinetic profiles of PNS. The integrated pharmacokinetic parameters were then calculated from non-compartmental model analysis.</p><p><b>RESULT</b>Rb1, Rg1 and R1 diffused through the round window membrane into PL of the inner ear, and then transported to the brain after IT of PNS solution. However, the pharmacokinetic parameters showed significant differences between the three components. Based on the self-defined AUC weighting coefficients integration approach, the holistic pharmacokinetic profiles of PNS were obtained, from which the integrated pharmacokinetic parameters were calculated. The C(max) in CSF and brain tissues following IT were respectively 1.5 and 0.4-fold higher than those following IV. After IT, the AUC in CSF and brain tissues increased by 0.5 and 1.2 times compared with IV. Furthermore, the C(max) and AUC in plasma following IT were respectively 45.9% and 33.1% lower than those following IV.</p><p><b>CONCLUSION</b>This novel intra-cochlear administration might serve as a potential and promising alternative to TCM delivery with enhanced brain-targeted efficiency.</p>

Fístula perilinfática em cobaias: comparação entre evolução natural e correção cirúrgica / Perilymphatic fistula in guinea pigs: natural evolution versus surgical treatment

As fístulas perilinfáticas ainda constituem um grande desafio quanto ao seu tratamento. Em alguns casos, seu fechamento cirúrgico pode reduzir as sequelas auditivas e vestibulares. OBJETIVO: Comparar o comportamento de fístulas perilinfáticas de janela coclear em cobaias quanto à evolução natural e fechamento cirúrgico imediato. MATERIAL E MÉTODOS: Estudo experimental. Quarenta cobaias foram submetidas à lesão da membrana da janela coclear e divididas em dois grupos aleatoriamente: fístula aberta (FA) e fístula fechada cirurgicamente (FF). Foram determinadas as amplitudes e latências do potencial de somação (PS) e do potencial de ação (PA) e da relação PS/PA em três momentos: pré-fístula (PRÉ), pós-fístula imediato (PFI) e pós-fístula tardio (PFT). RESULTADOS: Observou-se significativa queda das amplitudes e aumento das latências do PS e PA entre os momentos considerados. Quanto à relação PS/PA, houve diminuição entre PRÉ e PFI mas aumento entre PFI e PFT, ambos significantes. Não houve diferença de comportamento entre os grupos FA e FF. CONCLUSÕES: No período considerado, cobaias submetidas a lesões da membrana da janela coclear evoluíram com piora dos potenciais e latências. Apesar da melhora parcial dos parâmetros eletrofisiológicos o fechamento cirúrgico não se mostrou estatisticamente mais efetivo que a evolução natural das mesmas.

Perilymphatic fistulas still represent a major treatment challenge. In some cases, its surgical closure can reduce auditory and vestibular sequelae. AIM: to compare the behavior of cochlear window perilymphatic fistulas in guinea pigs as to their natural evolution and immediate surgical closure. MATERIALS AND METHODS: Experimental study. Forty guinea pigs were submitted to cochlear window membrane lesion and randomly broken down into two groups: open fistula (OF) and surgically closed fistula (SCF). We found the summation potential (SP) and action potential (AP) latencies and amplitudes and the SP/AP ratio at three times: pre-fistula (PRE), immediate post-fistula (IPF) and late post-fistula (LPF). RESULTS: There was a significant drop in amplitudes and raise in SP and AP latencies among the times studied. As to the SP/AP ratios, there was a reduction between PRE and IPF, both were significant. There was no behavior difference between the OF and SCF. CONCLUSIONS: Within the time frame considered, guinea pigs submitted to cochlear window membrane lesions evolved with a worsening in potentials and latencies. Despite the partial improvement in electrophysiological parameters, surgical closure did not prove statistically more effective than natural evolution.

Quantitative interpretation of dexamethasone pharmacokinetics in human inner ear perilymph using computer simulations / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To study the dexamethasone pharmacokinetics of human inner ear perilymph under different drug administration using computer simulations.@*METHOD@#The dexamethasone pharmacokinetics in guinea pigs inner ear perilymph under an intratympanic application with high-performance liquid chromatography. Dexamethasone pharmacokinetics in the guinea pigs cochlear fluid were simulated with a computer model, the Washington University Cochlear Fluids Simulator, version 1.6 and the best Simulations parameters to the experimental data could be obtain. With best Simulations parameters based on the experimental data, seven kinds application protocols were designed for human inner ear perilymph.@*RESULT@#After an intratympanic application dose of 0.5% dexamethasone 150 ml in guinea pigs, the T(1/2K) was (2.918 +/- 0.089) h, and Cmax was (231.25 +/- 6.89) microg/L. The best Simulations parameters were that concentration of the dexamethasone 21-Phosphate disodium salt was 0.5% and the formula weight was 516, as well as drug diffusion coefficient was 0.6939 x 10(-5) cm2/s and round window permeability was 2.2 x 10(-11) cm/s while drug clearance half time was 175 minutes and scala tympaniscala vestibuli communication was 45 minutes. After an intratympanic application dose of 0.5% dexamethasone 500 mL, which the applied drug stayed in contact with the round window membrane for 15, 30, 60 and 120 minutes, the Cmax was 32.8, 64.3, 122.6 and 203.3 microg/L and the AUC was 116.5, 229.1, 423.6 and 759.2 microg/(h x L), respectively. After an intratympanic application dose of 0.5%, 1%, 2% and 4% dexamethasone 500 ml, which the applied drug stayed in contact with the round window membrane for 30 minutes respectively, the Cmax was 64.3, 127.3, 255.4 and 575.6 microg/L respectively and the AUC was 229.1, 462.8, 920.59 and 1525.2 microg/(h x L), respectively.@*CONCLUSION@#The dexamethasone pharmacokinetics in human inner ear perilymph by computer simulations was reported. As the time contact with the round window membrane increased, the inner ear perilymph concentration of dexamethasone increased. As the concentration of dexamethasone increased, the inner ear perilymph concentration of drug increased.

A Case of Multiple Perilymph Fistula Induced by Tympanostomy Tube Insertion / 대한평형의학회지

This controversial diagnosis centers around the phenomenon of perilymph leaking from the inner ear into the middle ear cleft through the oval window, round window or other fissures in the bony labyrinth that may be abnormally patent. A perilymph fistula may develop after stapedectomy surgery, penetrating middle ear trauma, head trauma, barotrauma, or possibly spontaneously. Uncertainty regarding the clinical criteria for the diagnosis and the inability to document the presence of a microfistula at surgery contribute to the problematic nature of this diagnosis. However, this condition should be seriously considered in the patient with vertigo after head trauma, barotrauma injury, or previous middle ear surgery. It is particularly likely in patients with penetrating middle ear trauma with vertigo. Most authors agree that perilymph fistulas generally heal spontaneously, therefore a few days of bed rest is appropriate in acute cases. Cases suspected after penetrating trauma should be explored early if symptoms persist. Here, authors report a case of multiple perilymph fistula possibly caused by tympanostomy tube insertion in a 48-year-old man with a review of the literature.

Comparison of the antioxidants lipoic acid pharmacokinetics in inner ear between intravenous and intratympanic administration in guinea pigs / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To 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).</p><p><b>METHODS</b>Fifty-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.</p><p><b>RESULTS</b>A 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.</p><p><b>CONCLUSIONS</b>The 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.</p>