ENT Services Research Articles

Connexin 26 preverbal hearing impairment: Mutation prevalence and heterozygosity in a selected population: Problemas auditivos preverbales por Conexina 26: Prevalencia de mutacion y heterocigosidad en una población seleccionada

The objective of this investigation was to determine the prevalence of Cx26 mutations in familial and sporadic cases of non-syndromic preverbal hearing impairment (HI). Molecular analysis of the Connexin 26 (Cx26/GJB2) gene was performed in 271 non-consanguineous individuals from the north of Italy, enrolled in the study because of the presence of non-syndromic preverbal sensorineural HI. One hundred and fortysix subjects (group 1) were referred from different ENT, paediatric and clinical genetic services, while 125 individuals (group 2) underwent Cx26 analysis based on precise anamnestic and clinical criteria for non-syndromic HI and low risk of acquired deficit. All of the cases were also classified as familial or sporadic due to the presence or absence of other documented childhood HI in the family. Of the total 271 individuals, 36.9% were positive for Cx26 mutations: 37 belonged to group 1 and 63 to group 2, which delineates a statistically significant difference between the two groups. The difference is mainly attributable to sporadically occurring cases. No significant differences between group 1 and group 2 were found regarding the prevalence of the common 35delG variant and the number of unidentified putative Cx26 alleles, although these latter were shown to be higher in sporadically occurring cases of the unselected group 1. The difference observed in Cx26 prevalence can be explained by the clinical selection of group 2, which ensures minimum risk of including cases of acquired HI. In particular, in cases of sporadically occurring HI, the use of a defined protocol increases the chances of a positive molecular result, improving genetic counselling and the possibility of establishing better genotype-phenotype correlation. Our data raise questions about the possible interpretation of Cx26 heterozygosity in a selected population of hearing-impaired individuals.SumarioEl objetivo de esta investigatión fue determinar la prevalencia de las mutaciones de la Cx26 en casos familiares y esporádicos de impedimentos auditivos (HI) no sindrómicos preverbales. El análisis molecular del gen de la Conexina 26 (Cx26/GJB2) se llevó a cabo en 271 sujetos no consanguíneos del norte de Italia incluídos en el estudio por presentar un HI sensorineural no sindrómico. 146 sujetos (grupo 1) fueron referidos por servicios de ORL, de Pediatría o de Genética Clínica, mientras que 125 del grupo 2, siguieron el análisis de Cx26 con base en criterios anamnésicos y clínicos precisos para HI no sindrómicos y con bajo riesgo de deficit adquirido. Todos los casos fueron clasificados como familiares o esporádicos por la presencia o ausencia de otros HI infantiles documentados en la familia. Del total de 271 individuos, 36.9% fueron positivos para mutaciones de Cx26: 37 pertenecían al grupo 1 y 63 al grupo 2, lo que delínea una diferencia estadisticamente significativa entre los dos grupos. La diferencia es sobre todo atribuible a casos que ocurrieron esporadicamente. No hubo diferencias significativas entre ambos grupos en cuanto a la prevalencia de la variante 35delG y el numero de alelos supuestamente no identificados, a pesar de que estos últimos mostraron ser más en los casos que ocurrieron esporadicamente del grupo 1 no selecto. La diferencia observada en la prevalencia de la Cx26 puede explicarse por la selectión clínica del grupo 2, que asegura un minimo de riesgo de inclusion de casos de HI adquirido. En particular, en los casos de HI de ocurrencia esporadica, el uso de un protocolo definido aumenta las posibilidades de un resultado molecular positivo, con lo que mejora el consejo genetico y la posibilidad de establecer una mejor correlation genotipo-fenotipo. Nuestros datos plantean interrogantes sobre la posible interpretatión de la heterocigosidad de la Cx26 en una población seleccionada de individuos con impedimentos auditivos.

The Scottish tonsillectomy audit

SummaryRegional specialist societies offer a valuable mechanism for the conduct of medical audit. The experience of the audit sub-committee of The Scottish Otolaryngological Society in conducting an audit on laryngeal cancer encouraged us to undertake a larger audit of tonsillectomy practice in Scotland. Although the number of tonsillectomies performed has declined over the last 10 years, they still account for about 20 per cent of all operations performed by otolaryngologists and as such are a major consumer of resources (Personal communication – Directorate of Information Services, Information and Statistics Division. NHS in Scotland, Management Executive, Edinburgh). The Scottish tonsillectomy audit was devised to define current practice, review indications for surgery and recommend such modifications in practice as may be necessary to optimise patient care and the use of resources. Funding was obtained from the Clinical Resource and Audit Group (CRAG) of the Scottish Home and Health Department.Data on current practice was collected during the period February 1992 to January 1993. Proformas were completed by medical, administrative and secretarial staff in all participating hospitals, collected by an audit secretary and passed to the relevant data collection centre. Data was then entered into a specially designed database before being forwarded to the audit co-ordinator based in Dundee for collation. Six and 12 months following surgery, all inpatients were sent a questionnaire to obtain data on the efficacy of the operation.Data were obtained from a total of 9 773 patients. Two thousand and seventy-nine of these were seen as both outpatients and inpatients, 4 309 were outpatients only and 3 385 were inpatients only. Four thousand, one hundred and one patients returned at least one follow-up questionnaire.The topics audited included source and reason for referral, indications for surgery, grade of staff involved, type of surgery and length of stay in hospital. In agreement with previous studies (H.M.S.O., 1989), differences were found in the rates of tonsillectomy performed in different Health Boards. Although the highest referral and operation rates were found in the Highland region, referral and operation rates did not correlate in all other areas. Recurrent tonsillitis was the most frequent principal reason for the decision to operate although there were differences between Health Boards for other indications including obstructive symptoms. Most patients had symptoms for two to three years although some patients had been affected for 40 years prior to being listed for tonsillectomy. Some area ENT services were consultant-based while others involved more junior staff. The grade of staff involved did not appear to affect the decision made at the Outpatient Department (OPD) or the outcome of the operation.Ninety-eight per cent of patients who returned the questionnaire were glad that the operation had been performed.Recommendations regarding changes in tonsillectomy practice are given.

Anaesthesia for ENT surgery

In recent years there has been a considerable tendency in the United Kingdom to draw together ENT services into custom-built units, instead of providing a few beds in separate wards with limited access to operating theatre facilities. While this is undoubtedly good for patients and for the streamlining of services, it can make it difficult to offer the trainee anaesthetist good exposure to the techniques required for these combined airway procedures. The drawing together of ENT services does have other benefits. It allows surgeons and anaesthetists to consider more carefully their work and the results which are obtained. Now that clinical audit has become essential, the ability of consultants and trainees to work in close approximation to each other in a single discipline allows much better comparison of outcome than was possible when services were widely spread and operating time frequently available only in a shared theatre. ENT procedures are common, and account for approximately 5% of the workload of an anaesthetic department. ENT operations are rarely life-saving and therefore safety is the prime consideration. Many patients who present for surgery are children or young adults who are otherwise fit; however, some patients, who may present for major procedures, are older and may have concomitant disease of the respiratory or cardiovascular systems. In all categories of patient, the potential risk of anaesthesia in the presence of a compromised airway either during or after the procedure must never be underestimated.

Examination of the Larynx

To the Editor.— The cost of flexible laryngoscope (more than $2,500) is reason enough to emphasize that improved methods of teaching the otolaryngologic examination to medical students is needed. The physical diagnosis courses are taught by internists, who are not experts in the technique of the laryngoscopic examination. Following one session with a specialist, many of the students never again pick up a laryngoscopic mirror. Continued exposure (ie, rotations through ENT services) is the only way to develop the skills necessary for indirect laryngoscopy. The medical education system made a big mistake when it dropped the rotating internship. Medical schools should improve their understanding and education in this field. I believe that it is wrong to resort to expensive instrumentation when improved education is all that is needed.