Tortícolis congénita como forma de presentación del síndrome de Klippel-Feil / Congenital torticollis as a way of presentation of Klippel-Feil syndrome

El síndrome de Klippel-Feil (SKF) es una anomalía congénita caracterizada por la fusión de las vértebras cervicales como consecuencia de un defecto en la segmentación de la columna cervical entre la tercera y la octava semanas de gestación. Puede aparecer de forma aislada, asociada a otras alteraciones sistémicas y esqueléticas, o formar parte de algunos síndromes. La mayoría de los casos son esporádicos, aunque se han descrito casos familiares con una herencia autosómica dominante o recesiva. La tríada clínica característica (cuello corto, baja implantación del cabello y limitación en la movilidad del cuello) no es habitual. La tortícolis congénita es una forma de presentación precoz, pero poco frecuente. El estudio radiológico confirmará el diagnóstico; además, se requieren otros estudios para descartar anomalías asociadas. El tratamiento depende en gran medida de las alteraciones asociadas, así como de la presencia de síntomas neurológicos por compresión radicular o de la médula espinal. Presentamos el caso de un niño con tortícolis congénita como forma de presentación del SKF

Klippel-Feil syndrome (KFS) is characterized by congenital fusion of the cervical vertebrae because of a defect in the segmentation of the cervical spine between the 3rd and 8th week of pregnancy. It can be found isolated, associated with other systemic and skeletal disorders or be part of other syndromes. Most cases are sporadic, but familial cases with autosomal dominant or recessive inheritance have been described as well. Clinical triad findings (short neck, low posterior hairline, and limited cervical range of motion) are uncommon. Congenital torticollis is a form of early presentation, but rare. Imaging studies will confirm the diagnosis; in addition, further studies are required to exclude associated anomalies. Management of KFS depends on the associated features, as well as the presence of neurological symptoms because of nerve root or spinal cord compression. We present the case of a child with congenital torticollis as a way of KFS presentation

Matrix method for the study of wave propagation in one-dimensional general media.

A matrix method which relates the field and its derivative is presented for the study of wave propagation in any type of one-dimensional media. The transfer matrix is obtained from the canonical solutions of Helmholtz equations at normal incidence. The method is applied to different optical systems like a Fabry-Perot cavity formed by uniform fiber Bragg gratings, periodic dielectric structures and different quasi-periodic structures based on Fibonacci and Thue-Morse sequences of layers with constant and variable refractive index.

Application of the Fixed Point Theorem for the solution of the 1D wave equation: comparison with exact Mathieu solutions.

A method based in the application of Fixed Point Theorem (FPT) techniques to the solution of the 1D wave equation at normal incidence for materials that present a continuous (real or complex) dielectric constant is presented. As an example, the method is applied for the calculation of the electric field, reflection and transmission spectra in volume holographic gratings. It is shown that the solution obtained using this method agrees with the exact Mathieu solutions also obtained in this paper for volume holographic reflection gratings.

CT evaluation of underlying cause in spontaneous subcapsular and perirenal hemorrhage.

We evaluated the CT scans of 13 patients with spontaneous subcapsular or perinephric hemorrhage (SPH) associated with these underlying causes: 4 angiomyolipomas, 2 renal cell carcinomas, 1 renal metastatic malignant melanoma, 1 ruptured renal artery aneurysm, 1 adrenal myelolipoma, 1 ruptured renal abscess, 2 ruptured hemorrhagic cysts, and 1 patient with undiagnosed coagulation disorder. Our objective was to ascertain whether an underlying cause of SPH was identifiable by CT, and to determine the extension of the hematomas. Computed tomography identified the hematoma in all 13 cases (sensitivity 100 %). In all 12 cases in which there was a renal or adrenal anatomic lesion, the underlying cause was identified with CT (100 %), with correct diagnosis in 11 cases (91.6 %). The case in which no lesion was identified was the undiagnosed coagulation disorder. We conclude that CT is a useful technique for the initial evaluation of SPH, permitting diagnosis of hemorrhage and identification of the underlying cause.