Fractures of the tibial plateau. Influence of the type of fracture and precision of the articular reduction on the prognosis

Se realizó un estudio retrospectivo en 43 pacientes tratados de 45 fracturas de pilón tibial entre 1990 y 1998. Según la clasificación de Rüedi y Allgöwer 6 fracturas eran tipo I (13,3%), 6 tipo II (13,3%) y 33 tipo III (73,3%). El tratamiento realizado fue manipulación e inmovilización en botín de yeso en 8 fracturas, las seis del tipo I y dos del tipo II. En las 37 fracturas restantes se realizó osteotaxis y osteosíntesis. Los resultados clínicos obtenidos fueron excelentes-buenos en 27 de las fracturas (60%), valorados por parámetros objetivos, pero solo en 16 de las fracturas (35,5%) cuando se valoraron por parámetros subjetivos. Se apreciaron mejores resultados clínicos objetivos/subjetivos cuando se consiguió una buena reducción articular y cuanto menor era el grado de desplazamiento y hundimiento de la fractura; en estos casos fue más difícil obtener una buena reducción articular. En 2 fracturas (25%) tratadas conservadoramente y en 17 (46%) tratadas quirúrgicamente se presentó al menos una complicación. Las fracturas de pilón tibial son fracturas graves, por la frecuencia de lesiones de partes blandas y de otras estructuras con que se asocian y por los resultados mediocres derivados de su tratamiento, que son peores en las fracturas tipo III y cuando no se consigue una correcta reducción articular

Geology of the Cerro Quema Au-Cu deposit (Azuero Peninsula, Panama)

The Cerro Quema district, located on the Azuero Peninsula, Panama, is part of a large regional hydrothermal system controlled by regional faults striking broadly E-W, developed within the Río Quema Formation. This formation is composed of volcanic, sedimentary and volcano-sedimentary rocks indicating a submarine depositional environment, corresponding to the fore-arc basin of a Cretaceous–Paleogene volcanic arc. The structures observed in the area and their tectono-stratigraphic relationship with the surrounding formations suggest a compressive and/or transpressive tectonic regime, at least during Late Cretaceous–Oligocene times. The igneous rocks of the Río Quema Formation plot within the calc-alkaline field with trace and rare earth element (REE) patterns of volcanic arc affinity. This volcanic arc developed on the Caribbean large igneous province during subduction of the Farallon Plate. Mineralization consists of disseminations of pyrite and enargite as well as a stockwork of pyrite and barite with minor sphalerite, galena and chalcopyrite, hosted by a subaqueous dacitic lava dome of the Río Quema Formation. Gold is present as submicroscopic grains and associated with pyrite as invisible gold. A hydrothermal alteration pattern with a core of advanced argillic alteration (vuggy silica with alunite, dickite, pyrite and enargite) and an outer zone of argillic alteration (kaolinite, smectite and illite) has been observed. Supergene oxidation overprinted the hydrothermal alteration resulting in a thick cap of residual silica and iron oxides. The ore minerals, the alteration pattern and the tectono-volcanic environment of Cerro Quema are consistent with a high sulfidation epithermal system developed in the Azuero peninsula during pre-Oligocene time

Geology of giant quartz veins and their host rocks from the Eastern Pyrenees (Southwest Europe)

Giant Quartz Veins (GQVs) are ubiquitous in different tectonic settings and, besides being often related to hydrothermal ore deposits, also represent large-scale fingerprints of the structural and geochemical history of the rocks in which they are hosted. Here we present detailed geological maps and interpretations of three key areas of the Eastern Pyrenees where GQVs are well exposed. The studied rocks record different styles of deformation and are representative of common settings of the Pyrenees where GQVs are present: pre-Variscan metasedimentary and metavolcanic rocks, late Variscan granitoids, and Mesozoic and Cenozoic sedimentary rocks. GQVs in the study areas formed along pre-existing brittle and ductile structures or at locations with lithological heterogeneities, and have alteration haloes of silicified host rocks. The geological maps and interpretations presented here contribute to gain insights into the formation mechanisms of GQVs and into the structural constraints on fluid flow and mineral reactions at different depths of the Earth's crust

Aortic perforation by active-fixation atrial pacing lead: an unusual but serious complication

Perforation of a cardiac chamber is an infrequent but serious sequela of pacemaker lead implantation. An even rarer event is the perforation of the aorta by a protruding right atrial wire. We present here the first case in the medical literature of aortic perforation as a sequela to the implantation of a cardiac resynchronization therapy defibrillator. The patient was a 54-year-old man with idiopathic dilated cardiomyopathy who underwent the implantation of a defibrillator, with no apparent sequelae. Six hours after the procedure, he experienced cardiac tamponade and required urgent open-chest surgery. The pericardial effusion was found to be caused by mechanical friction of a protruding right atrial wire on the aortic root. The aortic root and the atrial wall were both repaired with Prolene suture, which achieved complete control of the bleeding. There was no need to reposition the atrial wire. The patient had a good postoperative recovery

F-bearing sediments and rocks in the East African Rift: characterization and evaluation of F release capacity

Fluoride represents one of the most severe natural contaminant that affects groundwater as well as rivers and soils. More than 200 million people worldwide consume water with fluoride concentration exceeding the WHO guideline of 1.5 mg L-1 (WHO, 2008)