RESUMEN
OBJECTIVE: To investigate Fallopian canal dehiscence (FCD) during cholesteatoma surgery. STUDY DESIGN: Prospective case-control study. PATIENTS: Four hundred and one patients with cholesteatoma and 172 with otosclerosis. INTERVENTIONS: Therapeutic. SETTING: District general hospital. MAIN OUTCOME MEASURES: (i) Intra-operative incidence of FCD during (a) surgery for cholesteatoma versus a homogeneous control group (patients with otosclerosis); (b) revision surgery for cholesteatoma as compared to primary surgery. (ii) Intra-operative incidence of a fistula if FCD is present. RESULTS: Data were prospectively collected and analysed using chi-square tests. FCD was found in 19% of cases versus 5.2% of controls. Intra-operative incidence of (i) FCD during cholesteatoma surgery versus otosclerosis surgery was statistically very highly significant (P < 0.0001, OR = 5.43); (ii) FCD during revision versus primary cholesteatoma surgery was not statistically significant (P = 0.83); and (iii) encountering a fistula in the presence of FCD during cholesteatoma surgery was statistically very highly significant (P < 0.0001, OR = 6.71). CONCLUSIONS: A surgeon is more likely to encounter FCD during cholesteatoma surgery than in stapes surgery. If during cholesteatoma surgery FCD is found, then a fistula is also more likely to be present, mainly of the semicircular canal. The incidence of FCD is not increased in revision surgery. These findings are very relevant for any otologist undertaking cholesteatoma surgery.
Asunto(s)
Colesteatoma del Oído Medio/cirugía , Complicaciones Intraoperatorias/epidemiología , Procedimientos Quirúrgicos Otológicos , Dehiscencia de la Herida Operatoria/epidemiología , Salud Global , Humanos , Incidencia , Estudios ProspectivosRESUMEN
OBJECTIVE: To determine the COMQ-12 score in an adult population without active COM. DESIGN: Analysis of COMQ-12 scores in participants without active COM. SETTING: East Anglia, United Kingdom. PARTICIPANTS: 70 healthy volunteers recruited from two local hospitals. MAIN OUTCOME MEASURES: COMQ-12. RESULTS: The median COMQ-12 score overall was two and the modal score was 0 with 27 (39%) participants achieving this score. CONCLUSION: We recommend that the 'normal' values defined in this study be seriously considered before contemplating intervention, especially when patients with low scores are considered for surgery.
Asunto(s)
Enfermedades del Oído , Oído Medio , Encuestas y Cuestionarios , Adulto , Enfermedad Crónica , Enfermedades del Oído/cirugía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Otitis Media , Calidad de VidaRESUMEN
OBJECTIVE: A specialist balance clinic to effectively deal with dizzy patients is recommended by ENT-UK. We audit the patient pathway before and following the introduction of a consultant-led dedicated balance clinic. DESIGN: Process evaluation and audit. SETTING: ENT outpatients department of a district general hospital. MAIN OUTCOME MEASURES: The journey of dizzy patients seen in the general ENT clinic was mapped from case notes and recorded retrospectively. A consultant-led, multidisciplinary balance clinic involving an otologist, a senior audiologist and a neurophysiotherapist was then set up, and the journey was prospectively recorded and compared with that before the change. RESULTS: Of the 44 dizzy patients seen in the general clinic, 41% had further follow-up consultations; 64% were given definitive or provisional diagnoses; 75% were discharged without a management plan. Oculomotor examination was not systematically performed. The mean interval between Visits 1 and 2 was 8.4 weeks and the mean number of visits was 3. In the consultant-led dedicated balance clinic, following Visit 1, only 8% of patients required follow-up; 97% received definitive diagnoses, which guided management; all patients left with definitive management plans in place. In all patients, oculomotor assessment was systematically performed and all patients received consultant and, where necessary, allied healthcare professional input. CONCLUSIONS: By standardising the management experience for dizzy patients, appropriate and timely treatment can be achieved, allowing for a more seamless and efficient patient journey from referral to treatment. A multidisciplinary balance clinic led by a consultant otologist is the ideal way to achieve this.
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Consultores , Manejo de la Enfermedad , Trastornos de la Audición/terapia , Hospitales Generales/organización & administración , Auditoría Administrativa , Derivación y Consulta/organización & administración , Humanos , Estudios Retrospectivos , Reino UnidoRESUMEN
BACKGROUND: Subjective tinnitus is a common symptom, and there is often an underlying otological cause. This study investigated the degree of tinnitus-related annoyance in patients with chronic otitis media and analysed whether associations with tinnitus severity exist. METHOD: The multinational collaborative Chronic Otitis Media Questionnaire-12 study collected prospective data on 478 adult patients suffering from chronic otitis media across 9 otology referral centres in 8 countries. Based on this dataset, we investigated tinnitus severity using participant responses to item 7 of a native version of the Chronic Otitis Media Questionnaire-12. RESULTS: With respect to tinnitus severity, 23.8 per cent, 17.4 per cent, 15.5 per cent, and 43.4 per cent of participants reported no, minor, moderate, and major inconvenience or greater, respectively. The absence of ear discharge, absence of cholesteatoma, and poorer disease-specific health-related quality-of-life were associated with increased tinnitus severity in patients with chronic otitis media, whereas age, hearing disability and geographical region showed no association. CONCLUSION: This analysis provided novel insight into potential risk factors for tinnitus in patients with chronic otitis media.
Asunto(s)
Otitis Media , Acúfeno , Humanos , Adulto , Acúfeno/epidemiología , Acúfeno/etiología , Estudios Prospectivos , Otitis Media/complicaciones , Otitis Media/epidemiología , Encuestas y Cuestionarios , Enfermedad Crónica , Factores de RiesgoAsunto(s)
Colesteatoma del Oído Medio/cirugía , Apófisis Mastoides/cirugía , Timpanoplastia/métodos , Adolescente , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Factores de Tiempo , Resultado del Tratamiento , Adulto JovenRESUMEN
Bismuth Iodoform Paraffin Paste (BIPP) is one of the most commonly used packs after middle and external ear surgery. Only two retrospective case studies exist which found a 0.4% and 6% overall risk of BIPP allergy. The result of our prospective patch testing study identifies the true incidence of BIPP allergy to be 12% in those previously exposed and 1% in those not previously exposed. The component part responsible is iodoform not iodine. We recommend patch testing patients previously exposed to BIPP undergoing ear surgery, if postoperative BIPP packing is being considered. We recommend those patients allergic to BIPP should be tested with its constituent parts for future reference. It is important to determine whether there is allergy to iodine solution or not as this would preclude them from future iodine solution contrast studies and iodine solution skin prep before surgery. We do not recommend testing patients not previously known to be exposed to BIPP as the incidence of allergy is low and there exists a risk of sensitization.
Asunto(s)
Bismuto/efectos adversos , Hipersensibilidad a las Drogas/diagnóstico , Hipersensibilidad a las Drogas/prevención & control , Hidrocarburos Yodados/efectos adversos , Procedimientos Quirúrgicos Otológicos , Complicaciones Posoperatorias , Adolescente , Adulto , Anciano , Niño , Estudios de Cohortes , Bases de Datos Factuales , Combinación de Medicamentos , Hipersensibilidad a las Drogas/epidemiología , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pruebas del Parche , Cuidados Preoperatorios , Estudios RetrospectivosRESUMEN
OBJECTIVE: The Chronic Otitis Media Questionnaire 12 was developed initially in the UK to assess patient-reported health-related quality of life associated with chronic otitis media. This study aimed to determine whether this tool is applicable to the Russian population, which has a materially different healthcare system. METHOD: A total of 108 patients with different forms of chronic otitis media completed the Russian Chronic Otitis Media Questionnaire 12. RESULTS: The average Russian Chronic Otitis Media Questionnaire 12 score was 19.4 (standard deviation = 8.3). The internal consistency of the Russian Chronic Otitis Media Questionnaire 12 was high, with a Cronbach's alpha value of 0.860. CONCLUSION: The Russian version of the Chronic Otitis Media Questionnaire 12 was found to be a reliable tool for the assessment of health-related quality of life in patients with chronic otitis media. This sets the scene for international collaboration, using this tool to assess the effectiveness of surgical treatments even amongst countries with different healthcare systems.
Asunto(s)
Comparación Transcultural , Otitis Media/psicología , Medición de Resultados Informados por el Paciente , Calidad de Vida , Encuestas y Cuestionarios/normas , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Femenino , Humanos , Lenguaje , Masculino , Persona de Mediana Edad , Otitis Media/cirugía , Reproducibilidad de los Resultados , Federación de Rusia , Traducciones , Reino Unido , Adulto JovenRESUMEN
OBJECTIVE: To identify the stapedotomy learning curve of two U.K. otolaryngologists. STUDY DESIGN: A retrospective review of the outcome of first 100 stapedotomy operations by each surgeon. Included in the study was a postal survey of the incidence of stapes surgery by U.K. otolaryngologists. SETTING: Two tertiary referral centers. PATIENTS: All ears in which primary stapedotomy was performed for otosclerosis. Nonotosclerotic cases and malleus stapedotomy cases were excluded. INTERVENTION: One surgeon used the technique of small fenestra stapedotomy with either a Teflon-wire or titanium piston but without vein graft interposition, whereas the second used the technique of stapedotomy with vein graft interposition and a Teflon piston. MAIN OUTCOME MEASURES: A moving average with a window of 15 dB was used to plot learning curves for the postoperative air-bone gaps. Using a postoperative air-bone gap of 20 dB or better as a definition of 'success,' the success rates with the increase in surgical experience of both surgeons were plotted on graphs, the learning curves. The end point of the learning curve was defined as the point where the curve reached its peak, and the results were sustainable. RESULTS: There was no clear-cut end point in both learning curves, although it appears that there is a landmark point at 60 to 80 cases for both surgeons. Both surgeons also had one "dead ear" in their first 15 cases. The postal survey showed that some trainers only performed small numbers of stapes surgery, whereas some otolaryngologists who performed stapedotomies regularly were not trainers. CONCLUSIONS: The study supports a learning curve in stapes surgery. To maximize the training opportunity of trainee surgeons, it may be advisable for learning centers to form network to provide target training for the trainee who has demonstrated the necessary dexterity and temperament of an otologist.
Asunto(s)
Competencia Clínica , Educación de Postgrado en Medicina , Otosclerosis/cirugía , Cirugía del Estribo/métodos , Cirugía del Estribo/estadística & datos numéricos , Adulto , Audiometría de Tonos Puros , Femenino , Encuestas de Atención de la Salud , Humanos , Aprendizaje , Masculino , Persona de Mediana Edad , Otosclerosis/diagnóstico , Evaluación de Resultado en la Atención de Salud , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología , Estudios Retrospectivos , Medición de Riesgo , Cirugía del Estribo/efectos adversos , Encuestas y Cuestionarios , Resultado del Tratamiento , Reino UnidoRESUMEN
OBJECTIVE: The 5S model proposes five hierarchical levels (systems, summaries, synopses, syntheses and studies) of pre-appraised evidence to guide evidence-based practice. This review aimed to identify and summarise pre-appraised evidence at the highest available 5S level for the management of different subsets of otitis media: acute otitis media, otitis media with effusion, chronic suppurative otitis media and cholesteatoma in both adults and children. METHOD: Data sources were pre-appraised evidence resources. Evidence freely available from sources at the highest available level of the 5S model were summarised for this review. RESULTS: System level evidence exists for acute otitis media and otitis media with effusion. Summary level evidence exists for recurrent acute otitis media and medical management of chronic suppurative otitis media. There is an absence of randomised controlled trials to prove the efficacy of surgical management of chronic suppurative otitis media and cholesteatoma. CONCLUSION: Until randomised controlled trial data are generated, consensus publications on the surgical management of chronic suppurative otitis media and cholesteatoma should be used to guide best practice.
Asunto(s)
Otitis Media/terapia , Medicina Basada en la Evidencia , Humanos , Otitis Media/tratamiento farmacológico , Otitis Media/patología , Otitis Media/cirugíaRESUMEN
OBJECTIVES: To determine the outcome of myringoplasty as undertaken by ENT surgeons in the UK, and to assess the current systems available for providing national outcome data. METHODS: A prospective national multicentre audit was conducted involving multiple hospitals throughout the UK. Participants consisted of ENT surgeons practising in the UK. RESULTS: Data were prospectively collected over a three-year period between 1 March 2006 and 1 March 2009 using the web-based Common Otology Database. In total, 33 surgeons provided valid and complete data for 495 procedures. The overall closure rate for myringoplasty was 89.5 per cent. The average hearing gain for successful primary myringoplasties was 9.14 dB (standard deviation = 10.62). The Common Otology Database provided an effective platform for capturing outcome data. CONCLUSION: Myringoplasty is a safe and effective procedure in the UK. With the introduction of revalidation by the General Medical Council, participation in national audits will be mandatory in the future. This study demonstrates that a web-based audit tool would be suitable for performing such audits.
Asunto(s)
Miringoplastia/métodos , Evaluación de Resultado en la Atención de Salud , Adolescente , Adulto , Audiometría de Tonos Puros , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Auditoría Médica , Complicaciones Posoperatorias/diagnóstico , Estudios Prospectivos , Reino Unido , Adulto JovenRESUMEN
Previous studies have shown that amine groups are ototoxic. The interaction between different polyamines and phospholipid vesicles was studied using vesicle aggregation and fluorescence techniques (DPH and ANS as the fluorescence probes). The results showed that the interaction between polyamines (spermine, spermidine and 1,3-diaminopropane) and acidic phospholipids (PS, PE, PI and PIP2) is an ionic one. The polyamine with the highest positive charges and the phospholipid with the highest content of negative groups showed the strongest ionic interaction. There was no indication of any hydrophobic interaction within the phospholipid bilayer. The strong interaction between amine groups and PIP2 support the proposal that the latter is crucially involved in aminoglycoside toxicity in the inner ear and kidney.
Asunto(s)
Membrana Dobles de Lípidos/metabolismo , Fosfolípidos/metabolismo , Poliaminas/metabolismo , Aminoglicósidos/toxicidad , Naftalenosulfonatos de Anilina , FluorescenciaRESUMEN
AIM: One of the main factors in determining success rate of lacrimal surgery is the level of obstruction in the lacrimal drainage system. There are only few reports which quantify this, and none on endoscopic dacryocystorhinostomy (DCR). METHODS: A case series of patients who had endoscopic DCR for anatomical obstruction of the lacrimal drainage system was performed. All patients who had lacrimal blockage referred to a district general hospital, irrespective of the level of blockage, had endoscopic DCR as the initial treatment by the authors. A total of 191 endoscopic DCRs were performed between 1994 and 1999. No other forms of lacrimal surgery were performed during this period. The level of the obstruction was assessed by the ophthalmologist before the operation and confirmed at surgery. All cases were followed up for a minimum of 6 months, and 96 cases were also reviewed 12 months after surgery. The outcome of the endoscopic DCR operation for each eye was categorised into complete cure, partial cure, or no improvement according to the degree of symptomatic relief following the operation. RESULTS: Complete relief from epiphora was achieved in 89% of cases overall at 6 months. The success rate in cases with lacrimal sac/duct obstruction (93%) or common canalicular blockage (88%) was comparable. In canalicular obstruction, however, the complete cure rate was lower at 54%. The benefit of the operation was maintained at 12 months. CONCLUSION: This study demonstrates that the success rate of surgical (non-laser) endoscopic DCR is comparable to that reported for external DCR. Moreover, the technique is appropriate for initial treatment of patients with common canalicular or even canalicular obstruction.
Asunto(s)
Dacriocistorrinostomía , Endoscopía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
Extratympanic electrocochleography was performed on three patients following tobramycin injection and ten patients during cisplatin (cis-dichlorodiamine platinum II infusion. The compound eighth nerve action potential and the cochlear microphonic decreased considerably in magnitude up to 45 to 60 minutes after tobramycin injection, followed by a gradual recovery to normal in all three patients. During the eight hours of continuous cisplatin infusion, there was no significant change in the eighth nerve action potential and cochlear microphonic. The immediate effect of tobramycin on the cochlear output may be due to interference with the metabolism of the inner ear by the drug. The absence of electrocochleographic change during cisplatin infusion may be due to differences in the mechanism between cisplatin and aminoglycoside ototoxicity, or it may reflect the relatively nonototoxic potential of our chemotherapy regimen.
Asunto(s)
Audiometría de Respuesta Evocada , Cisplatino/administración & dosificación , Adolescente , Adulto , Anciano , Cisplatino/uso terapéutico , Potenciales Microfónicos de la Cóclea/efectos de los fármacos , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/fisiopatología , Humanos , Infusiones Parenterales , Persona de Mediana Edad , Factores de Tiempo , Tobramicina/uso terapéutico , Nervio Vestibulococlear/fisiopatologíaRESUMEN
It has been suggested that the aminoglycoside drugs are ototoxic because they contain amine groups that interact with membrane phospholipids. The interaction of kanamycin A and kanamycin B with vesicles containing various phospholipids was assessed from studies of vesicle aggregation and of the fluorescence of the probes 1-anilino-8-naphthalene sulfonic acid (ANS) and 1,6-diphenyl-1,3,5-hexatriene (DPH) added to the system. Kanamycin B, with 5 amino groups, showed a stronger interaction with the acidic phospholipids than kanamycin A, with only 4 amino groups. The evidence indicated that the interaction was an ionic one involving the charged groups of both components with penetration of the hydrocarbon interior of the bilayers. Of all the phospholipids tested polyphosphoinositide showed the greatest ability to interact with the kanamycins, supporting the proposal that interaction with this phospholipid may be the basis of the ototoxicity of aminoglycosides.
Asunto(s)
Kanamicina/análogos & derivados , Kanamicina/metabolismo , Lípidos de la Membrana/metabolismo , Fosfolípidos/metabolismo , Naftalenosulfonatos de Anilina , Difenilhexatrieno , Polarización de Fluorescencia , Colorantes Fluorescentes , Liposomas/metabolismo , Fosfatidilinositoles/metabolismo , Espectrometría de FluorescenciaRESUMEN
OBJECTIVE: This article reports the outcomes of a series of patients who underwent obliteration of the mastoid cavity using hydroxyapatite cement. A comparison is made with a group of patients who underwent similar surgery in the same period using hydroxyapatite granules. STUDY DESIGN: Nonrandomized observational analysis. SETTING: Tertiary otology unit. PATIENTS AND INTERVENTIONS: All patients requiring mastoid surgery and primary obliteration or revision mastoid surgery and obliteration. MAIN OUTCOME MEASURES: Dry cavity with full epithelialization and good tolerance to swimming at 1 year postoperatively. RESULTS: In four of eight patients who had obliteration using hydroxyapatite cement, there was infection of the obliteration site, requiring revision. All of the patients who had obliteration with hydroxyapatite granules had dry and well-epithelialized mastoid cavities at 1-year follow-up, with ears that tolerated swimming. CONCLUSION: The use of hydroxyapatite cement is not recommended in mastoid obliteration surgery.
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Materiales Biocompatibles , Cementos para Huesos/uso terapéutico , Durapatita/uso terapéutico , Apófisis Mastoides/cirugía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Cementos para Huesos/efectos adversos , Desbridamiento , Femenino , Estudios de Seguimiento , Humanos , Masculino , Microesferas , Persona de Mediana Edad , Colgajos Quirúrgicos , Resultado del TratamientoRESUMEN
OBJECTIVE: To report the long-term results in a series of ossiculoplasties using Ceravital prostheses. STUDY DESIGN: Retrospective case review. SETTING: District general hospital. PATIENTS: Ossiculoplasties using Ceravital prostheses were performed in 25 patients with a mean age of 39 years. Cholesteatoma was present in 9 cases and absent in 16 cases before surgery. The reconstruction was single stage in 23 cases and second stage in 2 cases. MAIN OUTCOME MEASURES: Hearing gain and prosthesis-related complications. The mean length of follow-up was 6 years 6 months. RESULTS: In the short term, the mean air-bone gap improved from 43 dB preoperatively to 24 dB 6 months postoperatively. In the long term, the results were as follows: good in 4 cases, absorption of the prosthesis in 9 cases, slippage of the prosthesis in 4 cases, extrusion of the prosthesis in 3 cases, atelectasis of the tympanic membrane in 2 cases, and unknown in 3 cases. The mean time for complications to become apparent was 6 years 4 months for absorption, 3 years 3 months for extrusion, 7 months for slippage, and 1 year 9 months for atelectasis. Revision surgery was performed on 11 of the 18 cases in which the results were poor. CONCLUSIONS: Ceravital prostheses highlight the potential complication of absorption of ossicular prostheses. Absorption takes much longer to become apparent than other complications such as extrusion, slippage, or atelectasis. The much higher rate of absorption in this series than in previous series with shorter follow-up times suggests that the rate of absorption increases significantly over time.
Asunto(s)
Materiales Biocompatibles/efectos adversos , Cerámica/efectos adversos , Prótesis Osicular/efectos adversos , Complicaciones Posoperatorias/etiología , Falla de Prótesis , Timpanoplastia , Absorción , Adolescente , Adulto , Anciano , Conducción Ósea/fisiología , Niño , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/cirugía , Diseño de Prótesis , ReoperaciónRESUMEN
Aminoglycosides are organic bases that contain multiple amino groups. The ototoxic potential of these amine groups was studied using spermine, which is a polyamine with four amine groups (two amino and two imino). Twenty-four pigmented guinea pigs were studied. One-tenth milliliter of different concentrations of kanamycin A sulfate or spermine were given intratympanically. The temporal bones were removed 4 days after the injections, and the cochleas were examined using the scanning electron microscope. The damage to the hair cells was recorded in cytocochleograms. The results show that spermine is cochleotoxic when given intratympanically. Dosage of 50 mumol for kanamycin A sulfate and 5 mumol for spermine caused total damage of the outer hair cells in all ears. Lower dosage of kanamycin A sulfate (20 mumol) and spermine (1 mumol) did not cause any histologically discernible changes.
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Cóclea/efectos de los fármacos , Kanamicina/farmacología , Espermina/farmacología , Aminoglicósidos/farmacología , Animales , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Kanamicina/administración & dosificación , Espermina/administración & dosificaciónRESUMEN
It has previously been shown that simple compounds with multiple amine groups are ototoxic, the degree of ototoxicity depending on the number of amine groups in the molecule. The relationship between the number of amino groups and ototoxicity in aminoglycoside was studied using kanamycin A and kanamycin B, which contain 4 and 5 amino groups respectively. Forty-five pigmented guinea pigs were injected intratympanically with 0.1 ml of different concentrations of kanamycin A and kanamycin B. The animals were sacrificed 4 days after injection and the organ of Corti was studied by scanning electron microscopy. It was found that on an equimolar basis, kanamycin B (with 5 amino groups) is more cochleotoxic than kanamycin A (with 4 amino groups). The greater cochleotoxic potential of kanamycin B may be explained by the higher cationic nature of the molecule due to protonation of the amino--NH2 groups at physiological pH, resulting in a greater affinity between the drug and the cell membrane.
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Cóclea/efectos de los fármacos , Kanamicina/análogos & derivados , Kanamicina/toxicidad , Órgano Espiral/patología , Animales , Cationes/fisiología , Relación Dosis-Respuesta a Droga , Oído Medio/efectos de los fármacos , Cobayas , Kanamicina/administración & dosificación , Microscopía Electrónica de Rastreo , Órgano Espiral/efectos de los fármacos , Órgano Espiral/ultraestructura , Relación Estructura-ActividadRESUMEN
It has previously been shown that polyamines are ototoxic. The relationship between the number of amine groups and ototoxicity was studied using spermine, spermidine and 1,3-diaminopropane, which are polyamines with differing numbers of amine groups. Fifty pigmented guinea pigs were studied by injecting 0.1 ml of different concentrations of spermine, spermidine or 1,3-diaminopropane intratympanically. The animals were sacrificed 4 days after the injection and the organ of Corti was studied by scanning electron microscopy. It was found that on an equimolar basis, spermine (with 4 amine groups) is more cochleotoxic than spermidine (with 3 amine groups), which is in turn more cochleotoxic than 1,3-diaminopropane (with 2 amine groups). The cochleotoxic potential of the amine groups may be a result of their cationic nature at physiological pH (7.4). This property might be part of the explanation of the ototoxicity of the aminoglycosides.
Asunto(s)
Cóclea/efectos de los fármacos , Diaminas/toxicidad , Espermidina/toxicidad , Espermina/toxicidad , Animales , Relación Dosis-Respuesta a Droga , Cobayas , Células Ciliadas Auditivas/efectos de los fármacos , Órgano Espiral/efectos de los fármacos , Relación Estructura-ActividadRESUMEN
Many studies have been reported on the intratympanic ototoxicity of different drugs in animal models. The recovery periods of the animals following intratympanic drug applications varied among these studies. The present study compares the cochlear damage caused by intratympanic kanamycin following short (4 days) and long (30 days) post-injection survival periods, using the guinea pig as the animal model. The degree of cochlear damage 4 days after kanamycin injection was consistent among the tested animals. The degeneration was mainly confined to the outer hair cells and almost all inner hair were spared. The change 30 days after kanamycin injection was more variable among the animals and both inner and outer hair cells were damaged. This shows that, although the damage to the cochlea after intratympanic aminoglycoside injection is progressive, a short post-injection recovery period is suitable for comparative intratympanic ototoxicity studies.