Breaking bony bridges by physeal distraction

Physeal distraction for breaking bony bridges and the late treatment of long bone deformities in children near maturity, has been used in our Department since June, 1983. In all cases (4 bones in 3 patients) a deformity was present at the extremity of a long bone due to a bony bridge caused by a previous injury to the growth cartilage. The results were excellent and in our opinion there are advantages over other methods. The operation itself is not extensive and very little damage is done. There is no need for internal fixation or bone grafts. It is possible to obtain lengthening and to adjust the angular correction during treatment. We conclude that it is possible to correct angular deformities and bone shortening due to bony bridges by physeal distraction without the need for resection of the bony bridge. At present we recommend this method in children near skeletal maturity, especially in those cases with bone shortening

Experimental physeal distraction in immature sheep

An experimental study on physeal distraction was carried out in the distal femur of 45 two-month-old lambs for the purpose of identifying the basic mechanism of lengthening as well as assessing growth cartilage viability after lengthening. The animals were divided into three groups, each with three subgroups, according to the distraction rate employed (2 mm/day, 1 mm/day, 0.5 mm/day) and the time at which the animals were killed (end of lengthening, 1.5 months postlengthening, and at six months of age). Another group of three animals whose femurs were lengthened at a rate of 0.5 mm/day was killed ten days postoperatively. Roentgenologic, specimen measurements, and histologic studies were performed on all animals. The results obtained showed that the basic mechanism for lengthening is the production of a physeal fracture between degenerative and calcified layers; this finding was consistent. It was also observed that the lower the rate of distraction employed, the greater was the short- and long-term viability of the growth cartilage. More specifically, optimal viability was observed when a distraction rate of 0.5 mm/day was employed

Correction of angular deformities by physeal distraction

Physeal distraction is an alternative to more conventional treatments for the correction of angular deformities of the long bones. Twenty deformities of the femur and tibia, nine of which also involved associated shortening, were partially or completely corrected. In eight cases, there was physeal bony bridge. Complete correction of the angular deformity was achieved in 17 patients, and in seven patients, more than 80% correction was achieved. There were complications in four patients that hindered complete correction of the deformity, or shortening, or both. The external control of the correction until consolidation occurs is progressive and fairly noninvasive. The method allows external control of the correction until consolidation; it acts at the site of the deformity itself and permits lengthening and angular correction during therapy. In deformities with a physeal bony bridge, correction can be achieved with physeal distraction alone, prior resection of the bridge is not unnecessary. The technique is indicated in cases of angular deformities in patients nearing skeletal maturity and particularly in subjects in whom there is associated shortening

Sensitivity of GNSS-R spaceborne observations to soil moisture and vegetation

Global navigation satellite systems-reflectometry (GNSS-R) is an emerging remote sensing technique that makes use of navigation signals as signals of opportunity in a multistatic radar configuration, with as many transmitters as navigation satellites are in view. GNSS-R sensitivity to soil moisture has already been proven from ground-based and airborne experiments, but studies using space-borne data are still preliminary due to the limited amount of data, collocation, footprint heterogeneity, etc. This study presents a sensitivity study of TechDemoSat-1 GNSS-R data to soil moisture over different types of surfaces (i.e., vegetation covers) and for a wide range of soil moisture and normalized difference vegetation index (NDVI) values. Despite the scattering in the data, which can be largely attributed to the delay-Doppler maps peak variance, the temporal and spatial (footprint size) collocation mismatch with the SMOS soil moisture, and MODIS NDVI vegetation data, and land use data, experimental results for low NDVI values show a large sensitivity to soil moisture and a relatively good Pearson correlation coefficient. As the vegetation cover increases (NDVI increases) the reflectivity, the sensitivity to soil moisture and the Pearson correlation coefficient decreases, but it is still significant.Postprint (author's final draft

La fijación externa monolateral en el tratamiento de las fracturas femorales del niño: experiencia preliminar en 20 casos

Veinte niños con fracturas femorales diafisarias simples fueron tratados mediante fijación externa con el aparato de Wagner. Once eran niños y 9 niñas, con una edad media de 8 años (3-15). Doce fracturas eran mediodiafisarias, 6 en el tercio proximal y 2 en el tercio distal. La hospitalización media fue de 9 días (5-20). La duración media de fijación externa fue de 61 días. Cinco casos precisaron de algún tratamiento adicional. En 3 pacientes se detectó una infección en el trayecto de los clavos y 1 de ellos necesitó retirada prematura del aparato. La movilidad articular de la rodilla se restableció de modo completo y constante excepto en 1 caso. En los casos seguidos más de 18 meses se observó un hipercrecimiento medio del fémur fracturado de 0,8 cm (0,5- 1,5). No hubo desaxaciones ni malrotaciones. Las ventajas de la fijación externa en el tratamiento de las fracturas femorales del niño incluyen Un mejor control de los fragmentos fracturarlos, una menor hospitalización y un cuidado más fácil y confortable de los pacientes. La infección del trayecto de los clavos parece ser la complicación más seria. En esta serie se detectó una curva de aprendizaje.Twenty children with simple femoral-shaft fractures were treated by monolateral external fixation with the Wagner device. There were 11 boys and 9 girls with a mean age of 8 years (3-15). Twelve fractures were located at the midshaft, 6 at the proximal third, and 2 other at the distal third of the femur. The mean hospital stay was 9 days (5-20). Mean external fixation time was 61 years. In 5 cases, additional methods of treatment were required. Pin tract infection occurred in 3 cases (one needed premature removal of the device). Except for one case, full range of knee motion was usually achieved after treatment. In patients followed for more than 18 months, a mean femoral overgrowth of 0.8 cm (0.5-1.5) was detected. Neither angular deformities nor malrotations were observed. In our experience, the main advantages of external fixation for femoral-shaft fractures in children include less hospitalization time and an easier and more confortable nursing. External fixation allows a better control of the bone fragments, providing an adequate stability. Pin tract infection seems to be the most important drawback. A learning curve was observed in this series