Revisión sobre los conocimientos actuales de dehiscencia del canal semicircular posterior / Review of current knowledge of the dehiscence in the semicircular posterior canal

La dehiscencia del canal semicircular posterior es una patología rara y con baja incidencia, por ello hemos realizado una revisión de los conocimientos actuales de esta entidad. Se ha realizado una búsqueda bibliográfica desde 1998 hasta diciembre de 2016 de toda la literatura publicada sobre la misma en las bases de datos Allied and Complementary Medicine Database and the Embase, Health Management Information Consortium, Scopus, Consortium, Medline, PsycINFO y Scielo. Se han encontrado y revisado 53 trabajos relacionados con el tema. La dehiscencia del canal semicircular posterior presenta una prevalencia variable; 0,3%-4,5% en adultos y 1,2%-20% en niños. Su localización puede ser hacia el golfo de la yugular o fosa cerebral posterior. Los pacientes pueden ser asintomáticos o presentar clínica auditiva y/o vestibular. La tomografía computarizada y la prueba de potenciales vestibulares miogénicos evocados permiten establecer el diagnóstico de certeza. En el tratamiento quirúrgico la vía de abordaje de elección es la transmastoidea y las técnicas del cierre del canal son el "plugging" y el "resurfacing".

The posterior semicircular canal dehiscence is a rare pathology and it has a low incidence. We have realized a review about the current knowledge of this entity. We have performed a bibliographic research from 1998 to 2016 December about the literature published in this subject, in the data basis Allied and Complementary Medicine Database and the Embase, Health Management Information Consortium, Scopus, Consortium, Medline, PsycINFO y Scielo. I thas been found and reviewed 53 papers about the topic. The posterior semicircular canal dehiscence has a variable prevalence: 0,3%-4-5% in adults and 1,2%-20% in children. The location can be in the jugular bulb or in the posterior brain fossa. Some patients can be asymptomatic, whereas others can have auditory and/or vestibular signs and symptoms. Computed tomography and test of vestibular evoked myogenic potentials allow the diagnosis of certainty. In the surgical treatment the approach of choice is transmastoid and techniques to close the canal are plugging and resurfacing.

Dehiscencia del canal semicircular superior: estudio de la incidencia anatómica / Dehiscence in the superior semicircular canal: anatomic incidence study

Introducción: La presencia de dehiscencia de canal semicircular superior presenta una notable diferencia entre la incidencia radiológica (del 1 por ciento al 19 por ciento) y la anatómica (entre 0,4 por ciento y 0,6 por ciento). Objetivo: El objetivo del trabajo es determinar la incidencia anatómica de la dehiscencia del canal semicircular superior y compararla con la incidencia radiológica. Material y método: Se estudia la incidencia de dehiscencia de canal semicircular superior en 80 cráneos (160 temporales). Resultados: Hemos observado la presencia de una dehiscencia del canal semicircular superior en un cráneo de los 80 estudiados, lo que representó una incidencia del 0,6 por ciento. Se discute las posibles causas porque la prevalencia de los estudios radiológicos es marcadamente superior a la de los estudios anatómicos. Conclusión: Es evidente que se realiza un "sobrediagnóstico" de dehiscencias del canal semicircular superior ya que los hallazgos anatómicos están muy lejos de los resultados obtenidos con técnicas de imagen.

Introduction: The presence of dehiscence in the superior semicircular canal shows a remarkable difference between radiological (from 1 percent to 19 percent) and anatomical incidence (between 0,4 percent and 0,6 percent) Aim: To determine the incidence anatomical superior semicircular canal dehiscence. Material and method: The incidence of dehiscence in superior semicircular canal in 80 skulls (160 temporal bones) is studied. Results: We have observed the presence of one dehiscence in the superior semicircular canal in one skull from the 80 studied, representing an incidence of 0.6 percent. The possible causes are discussed because of the prevalence of the radiological studies is highly superior to anatomical studies. Conclusion: It is obvious the over-diagnosis performed about the dehiscences in the superior semicircular canal since anatomical finds are quite different from the results obtained by means of image technics.

Clinical Characteristics of Benign Paroxysmal Positional Vertigo in Korea: A Multicenter Study

Benign paroxysmal positional vertigo (BPPV) is characterized by episodic vertigo and nystagmus provoked by head motions. To study the characteristics of BPPV in a large group of patients in Korea, we retrospectively analyzed clinical features of 1,692 patients (women: 1,146, 67.7%; men: 54.6, 32.3%; mean age: 54.8+/-14.0 yr), who had been diagnosed as BPPV by trained neuro-otologists Dizziness Clinics. The diagnosis of BPPV was based on typical nystagmus elicited by positioning maneuvers. Posterior semicircular canal was involved in 60.9% of the patients, horizontal canal in 31.9%, anterior canal in 2.2%, and mixed canals in 5.0%. The horizontal canal type of BPPV (HC-BPPV) comprised 49.5% of geotropic and 50.5% of apogeotropic types. We could observe significant negative correlation between the proportion of HC-BPPV of each clinic and the mean time interval between the symptom onset and the first visit to the clinics (r=-0.841, p<0.05). Most patients were successfully treated with canalith repositioning maneuvers (86.9%). The high incidence of HC-BPPV in this study may be explained by relatively shorter time interval between the symptom onset and visit to the Dizziness Clinics in Korea, compared with previous studies in other countries.