Influence of Sex and Age on Posterior Semicircular Canal Thickness.

OBJECTIVE: The aim of this study is to determine whether sex and age influence posterior semicircular canal (PSC) thickness. METHODS: This observational study was conducted in 3 tertiary hospitals. The minimal distance between the PSC and the posterior cranial fossa (PSC thickness) was estimated by thin-section multidetector row computed axial tomography (CAT) scan of the temporal bones. Nonselected consecutive patients of all ages (607 temporal bones) were considered. RESULTS: A significant effect was only detected for sex (F = 5.418, p = 0.020); PSC thickness showed a higher mean value in women (mean difference ± SE: 0.224 ± 0.096 mm). A significant and negative r value was detected for males aged >45 years (-0.173, p = 0.026); in that group of patients, PSC thickness decreased as age increased (0.018 ± 0.008 mm/year). For females aged ≤45 years, a significant and positive r value was found (0.198, p = 0.022); in that group, PSC thickness increased as age increased (0.020 ± 0.008 mm/year). CONCLUSIONS: PSC thickness did not significantly evolve with age in young males (≤45 years) but it decreased from age 45 years onwards. On the other hand, PCS thickness increased with age in women until the age of 45 years and it did not significantly change in older females.

Explicación ontogénica para la asociación entre dehiscencia del tegmen tympani y dehiscencia del canal semicircular superior / Ontogenetic explanation for tegmen tympani dehiscence and superior semicircular canal dehiscence association

Objetivos: Analizar la ontogenia del canal semicircular superior y del tegmen tympani y determinar si hay factores embriológicos comunes que expliquen la dehiscencia asociada de ambos. Métodos: Se han analizado 77 series embriológicas humanas de edades comprendidas entre las 6 semanas y recién nacidos. Las preparaciones estaban cortadas en serie y teñidas con la técnica de tricrómico de Martins. Resultados: La prolongación tegmentaria del tegmen tympani y el canal semicircular superior se originan de la misma estructura, la cápsula ótica, y poseen el mismo tipo de osificación endocondral; mientras que la prolongación escamosa del tegmen tympani se desarrolla desde la escama del temporal y su osificación es de tipo directa o intramembranosa. En la osificación de la prolongación tegmentaria colaboran los núcleos de osificación de los canales semicirculares superior, externo y accesorio del tegmen, los cuales por crecimiento se extienden hasta la prolongación tegmentaria, este hecho sumado a que ambas estructuras comparten una capa común de periostio externo podría explicar la coexistencia de falta de cobertura ósea en el tegmen y en el canal. Conclusión: El desarrollo del canal semicircular y tegmen tympani podrían explicar las causas de la asociación de ambas dehiscencias (AU)

Objectives: To analyze the ontogeny of the superior semicircular canal and tegmen tympani and determine if there are common embryological factors explaining both associated dehiscence. Methods: We analyzed 77 human embryological series aged between 6 weeks and newborn. Preparations were serially cut and stained with Masson's trichrome technique. Results: The tegmental prolongation of tegmen tympani and superior semicircular canal originate from the same structure, the otic capsule, and have the same type of endochondral ossification; while the extension of the squamous prolongation of tegmen tympani runs from the temporal squama and ossification is directly of intramembranous type. The nuclei of ossification of the superior and external semicircular canals and accessory of tegmen collaborate in the ossification of the tegmental extension and by growth extend to the tegmental prolongation. This fact plus the fact that both structures share a common layer of external periosteum could explain the coexistence of lack of bone coverage in tegmen and superior semicircular canal. Conclusion: The development of the semicircular canal and tegmen tympani could explain the causes of the association of both dehiscences (AU)

Ontogenetic explanation for tegmen tympani dehiscence and superior semicircular canal dehiscence association. / Explicación ontogénica para la asociación entre dehiscencia del tegmen tympani y dehiscencia del canal semicircular superior.

OBJECTIVES: To analyze the ontogeny of the superior semicircular canal and tegmen tympani and determine if there are common embryological factors explaining both associated dehiscence. METHODS: We analyzed 77 human embryological series aged between 6 weeks and newborn. Preparations were serially cut and stained with Masson's trichrome technique. RESULTS: The tegmental prolongation of tegmen tympani and superior semicircular canal originate from the same structure, the otic capsule, and have the same type of endochondral ossification; while the extension of the squamous prolongation of tegmen tympani runs from the temporal squama and ossification is directly of intramembranous type. The nuclei of ossification of the superior and external semicircular canals and accessory of tegmen collaborate in the ossification of the tegmental extension and by growth extend to the tegmental prolongation. This fact plus the fact that both structures share a common layer of external periosteum could explain the coexistence of lack of bone coverage in tegmen and superior semicircular canal. CONCLUSION: The development of the semicircular canal and tegmen tympani could explain the causes of the association of both dehiscences.

Peculiaridades en el desarrollo del canal semicircular superior / Peculiarities in the development of the superior semicircular canal

Objetivos: Realizar un estudio sobre la ontogénesis del canal semicircular superior con el fin de describir sus peculiaridades. Métodos: Para ello se han analizado 76 series embriológicas humanas de edades comprendidas entre los 32 días (6 mm) y recién nacidos. Las preparaciones estaban cortadas en serie y teñidas con la técnica de tricrómico de Martins. Resultados: En el desarrollo del canal semicircular hemos observado una serie de peculiaridades, como: secuencia cronológica definida de su osteogénesis con un ritmo de osificación variable, cada núcleo de osificación interviene en la formación de una de sus cubiertas, el superior de la superficial y el inferior de la profunda; la aparición de una dehiscencia transitoria, y el cierre del canal por hueso de tipo laminar con un grosor mínimo de 0,1 mm. Conclusión: Las peculiaridades en el desarrollo del canal podrían explicar las causas del origen de la dehiscencia patológica del mismo, ya sean congénitas o adquiridas (AU)

Objective: Our objective was to study the ontogeny of the superior semicircular canal in order to describe its peculiarities. Methods: We analyzed 76 series of human embryos aged between 32 days (6 mm) and newborns. The samples were cut serially and stained using Martin's trichrome technique. Results: In semicircular canal development there were a number of peculiarities, such as: a defined chronological sequence of osteogenesis with a variable rate of ossification; the fact that each nucleus of ossification was involved in the formation of one of its covers (the upper in the superficial and the lower in the deep); the appearance of transitory dehiscence; and canal closure by means of bone with laminar pattern, with a minimum thickness of 0.1 mm. Conclusion: The peculiarities in canal development could explain the origin of pathological dehiscence in the canal, whether congenital or acquired (AU)

[Peculiarities in the development of the superior semicircular canal]. / Peculiaridades en el desarrollo del canal semicircular superior.

OBJECTIVE: Our objective was to study the ontogeny of the superior semicircular canal in order to describe its peculiarities. METHODS: We analyzed 76 series of human embryos aged between 32 days (6mm) and newborns. The samples were cut serially and stained using Martin's trichrome technique. RESULTS: In semicircular canal development there were a number of peculiarities, such as: a defined chronological sequence of osteogenesis with a variable rate of ossification; the fact that each nucleus of ossification was involved in the formation of one of its covers (the upper in the superficial and the lower in the deep); the appearance of transitory dehiscence; and canal closure by means of bone with laminar pattern, with a minimum thickness of 0.1mm. CONCLUSION: The peculiarities in canal development could explain the origin of pathological dehiscence in the canal, whether congenital or acquired.

Intimal thickenings in the inferior epigastric artery and coronary bypass.

OBJECTIVE: To investigate the relationship between the inferior epigastric artery and the development of pathological intimal thickenings. MATERIAL AND METHODS: The inferior epigastric artery structure was studied with conventional histology techniques, histochemistry, immunohistochemistry and morphometry. RESULTS: The inferior epigastric artery develops 2 types of intimal thickenings: physiological and pathological. In our study, the pathological or atherosclerotic thickenings in this artery were not very common: they were present in 28% of the analysed cases. Vessel flow was not affected as shown by the intimal thickness index (I.T.I.) and the lumen reduction index (L.R.I.). The alpha-actin technique confirmed the role of the smooth muscle cells in the genesis of the thickening. Furthermore, histochemistry demonstrated that the extracellular matrix is rich in highly sulphated acid mucopolysaccharides. CONCLUSION: The inferior epigastric artery seems to be a good candidate for grafting in coronary revascularization because of the low susceptibility to thickening of its intima and the minimal repercussion on its blood flow.