RESUMO
Background: Jugular foramen lesions are among the major complications of skull base surgery. Morphological variations in the structure are pertinent during interpretation of skull base radiographs and in surgical procedures within the foramen. This study therefore aimed at describing the morphology of the jugular foramen in a Kenyan population. Methods: One hundred and five adult skulls from the Nairobi National Museums were used. Jugular foramen septation, dome and dimensions were studied extracranially. Statistical analysis was performed using SPSS (Version 21.1 IBM). Results: Septation was present in 202 (96.2%) jugular foramina, type I partial septation being the most common (78.7%). A dome was observed in 81 (38.6%) jugular foramina. Respectively, the mean right and left anteroposterior dimensions were 11.17 ±2.05mm vs.8.88 ±2.30mm (p <0.001), mediolateral dimensions 17.47 ±2.18mm vs. 15.30 ±2.53mm (p <0.001), jugular dome depth 12.38 ± 2.64 mm vs. 11.25 ± 2.15 mm (p=0.054), posterior wall thickness7.95 ± 2.20mm vs. 9.68 ± 1.98mm (p <0.001) and medial wall thickness 3.73 ± 1.10 mm vs. 3.73 ± 0.98mm (p = 0.992). Conclusion: Partial septation, asymmetry in dimensions and a wide range in the dome depth of the jugular foramen were frequent. Preoperative imaging of jugular foramen morphology is therefore recommended to avoid inadvertent injury to its contents and surrounding structures owing to variability.
RESUMO
Monocular deprivation results in anatomical changes in the visual cortex in favor of the non-deprived eye. Although the retina forms part of the visual pathway, there is scarcity of data on the effect of monocular deprivation on its structure. The objective of this study was to describe the effects of monocular deprivation on the retinal ganglion cell dendritic features. The study design was quasi-experimental. 30 rabbits (18 experimental, 12 controls) were examined. Monocular deprivation was achieved through unilateral lid suture in the experimental animals. The rabbits were observed for three weeks. Each week, 6 experimental and 3 control animals were euthanized, their retina harvested and processed for light microscopy. Photomicrographs of the retina were taken using a digital camera then entered into FIJI software for analysis. The number of primary branches, terminal branches and dendritic field area among the non-deprived eyes increased by 66.7%(p=0.385), 400%(p=0.002), and 88.4%(p=0.523) respectively. Non-deprived eyes had 114.3% more terminal dendrites (p=0.002) compared to controls. Among deprived eyes, all variables measured had a gradual rise in the first two weeks followed by decline with further deprivation. There were no statistically significant differences noted between the deprived and control eyes. Monocular deprivation results in increase in synaptic contacts in the non-deprived eye, with reciprocal changes occurring in the deprived eye.
La privación monocular de la visión resulta en cambios anatómicos en la corteza visual en favor del ojo no privado. Aunque la retina forma parte de la vía visual, hay escasez de datos sobre el efecto de la privación monocular en su estructura. El objetivo de esta investigación fue describir los efectos de la privación monocular en las características de las dendritas de las células ganglionares de la retina. Se diseñó un estudio cuasi-experimental. Se examinaron 30 conejos (18 experimentales, 12 controles). La privación monocular se logró a través de la sutura unilateral del párpado en los animales de experimentación. Los conejos fueron observados durante tres semanas. Cada semana, 6 animales experimentales y 3 control fueron eutanasiados, donde se obtuvo la retina y fue procesada para realizar microscopía óptica. Las microfotografías de la retina fueron tomadas con una cámara digital y luego se utilizó el software FIJI para su análisis. El número de dendritas primarias, terminales y el área del campo de dendritas en los ojos no privados aumentó un 66,7% (p=0,385), 400% (p=0,002), y 88,4% (p=0,523), respectivamente. Los ojos no privados, tenían 114,3% más dendritas terminales (p=0,002) en comparación con los controles. Entre los ojos privados, todas las variables medidas tuvieron un aumento gradual en las dos primeras semanas, seguido de descenso con mayor privación. No se observaron diferencias estadísticamente significativas entre los ojos privados y el grupo control. En conclusion, la privación monocular produce un aumento de los contactos sinápticos en los ojos no privados, con cambios recíprocos que se manifiestan en los ojos privados de la visión.