High-resolution computerized tomography for ossicular replacement prostheses

Introduction To study the accuracy of high-resolution computed tomography (HRCT) for assessing the ossicular structures in cadaveric temporal bone by the distance between temporal bone elements is of great interest. Objectives To record the distances between the malleal neck and both the stapedial head and footplate by HRCT. Further, after partially opening the temporal bone toward the ossicular structure, to record the actual distances between those structures during surgical dissection. Material and methods This study compared actual and HRCT measurements of cadaveric temporal bone. We studied, measured, and recorded distances within and between various structural elements. All data are reported as means and were analyzed to prove the accuracy of HRCT to assess ossicular structure from the temporal bone. Results This study included the temporal bones of 10 male and 10 female cadavers (mean age, 70.4 years). By surgical dissection, the distances between the malleal neck and the stapedial head and footplate were 3.40 and 5.30 mm, respectively (measured from the bone); by HRCT, the corresponding values were 3.35 and 5.29 mm. The intraclass correlation coefficients for assessing ossicular structure in contrast to the actual measurements were 0.901 (malleal neck to stapedial head) and 0.923 (malleal neck to stapedial footplate) (p < 0.05). There were no differences between the actual malleal neck to stapedial head (p = 0.793) or footplate (p = 0.242) measurements. Conclusion HRCT produced statistically comparable, reliable, and accurate measurements compared with actual measurements in cadaveric temporal bone. (AU)

Arteria estapedial persistente / Persistent stapedial artery

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Desarrollo ontogénico de la articulación incudoestapedial / Ontogenic development of the incudostapedial joint

Objetivo: Estudiar el desarrollo de la articulación incudoestapedial en embriones y fetos humanos. Material y método: Se han estudiado 46 huesos temporale scon ejemplares comprendidos entre 9 mm y recién nacidos. Las preparaciones estaban cortadas en serie y teñidas con la técnica de tricrómico de Martins. Resultados: La articulación incudoestapedial adquiere las características de una articulación sinovial de tipo enartrosisa las 16 semanas de desarrollo. El cartílago que recubre las superficies articulares está formado por diferentes estratos que se desarrollan sucesivamente: el superficial, a las 19 semanas; el de transición, entre las 20 y las 23 semanas, y el radial, a partir de las 24 semanas. El hueso subcondral se desarrolla a partir de las 29 semanas por los mecanismos de aposición y extensión del periostal y el endostal, pero no es hasta la semana 34 cuando recubre por completo las superficies articulares, constituidos los fascículos óseos por los que se transmitirán las líneas de fuerza. La cápsula articularse forma a partir de la interzona, la zona superficial desarrolla el ligamento capsular y la interna, la sinovial. Conclusiones: En el momento del nacimiento la articulación incudoestapedial está completamente desarrollada (AU)

Objective: To study the development of the incudostapedial joint in human embryos and foetuses. Material and method: 46 temporal bones with specimens between 9 mm and new-borns were studied. The preparations were sliced serially and dyed using the Martins trichrome technique. Results: The incudostapedial joint takes on the characteristics of a spheroidal joint at 16 weeks of development. The cartilage covering the articular surfaces is formed by different strata that develop in succession: the superficial stratum at 19 weeks, the transitional between 20 and 23 weeks, and the radial from 24 weeks on. The subchondral bone develops after 29 weeks by the mechanisms of apposition and extension of the periosteal and endosteal bones, but it is not until week 34 that it completely covers the articular surfaces, following constitution of the bone fascicles transmitting the lines of force. The articular capsule is formed from the inter-zone, the surface zone develops the capsular ligament, and the internal surface develops the synovial membrane. Conclusions: At the time of birth, the incudostapedial joint is completely developed (AU)

Agenesia de la supraestructura del estribo / Congenital absence of the stapes suprastructure

La ausencia de la supraestructura del estribo es una anomalía congénita muy rara, secundaria a un desarrollo aberrante del segundo arco branquial con ausencia parcial de las estructuras derivadas de él. En la mayoría de las ocasiones, su diagnóstico es casual en una timpanotomía exploradora realizada ante una hipoacusia de transmisión de origen incierto. Puede aparecer de forma aislada o asociada a otras anomalías mayores o menores. El tratamiento es quirúrgico. Realizamos una revisión de la literatura existente, a propósito de un caso de ausencia de la supraestructura del estribo aislada

Congenital absence of the stapes suprastructure is an unusual anomaly, consequence of a developmental aberration involving partial absence of a derivate from the second branchial arch. Sometimes, exploratory tympanotomy may be the only mean of diagnosis when known conductive hearing loss is seen. This anomaly can appear isolated or associated to other major or minor anomalies. The treatment is surgical. We review the literature about the absence of the isolated stapes suprastructure

Aportación al estudio de la otosclerosis y del síndrome de Van der Hoeve / Otosclerosis and Van der Hoeve's syndrome: a contribution

Hemos realizado un estudio ultraestructural y microanalítico de estribos procedentes de pacientes otosclerosos, sanos y afectos por el síndrome de Van der Hoeve a fin de determinar los cambios en la composición mineral de los mismos. Para ello hemos utilizado métodos no destructivos microscopía electrónica de barrido asociado a espectroscopia por dispersión de energía de rayos X (EDAX)- y otros destructivos (espectrografía con infrarrojos mediante transformada de Fourier). Utilizando la relación Ca/P hemos determinado que la composición mineral de los estribos es distinta en individuos normales, otosclerosos y afectos por el síndrome de Van der Hoeve. En esta última entidad hemos detectado una composición mineral inusual en huesos sanos: la brushita (AU)

Morphological and microchemical changes that effect to the otosclerotic stape in the Van der Hoeve's syndrome were examined with a scanning electron microscope equipped with an energy dispersive X-ray fluorescence. Using the Ca/P ratio as criterion--measured by the characteristic x-ray fluorescence--it was shown that the Van der Hoeve stape had a higher Ca/P ratio (2.6:1) as compared to the normal stape (2:1). The Van der Hoeve's syndrome lesions as poorly mineralized, with low calcium salt and apparent increase of phosphates. This finding indicates a possible change from hydroxyapatite (or apatite) to brushite, which imply an acidification of bone (AU)