Safe areas for the placement of standard shoulder arthroscopy portals: an anatomical study / Áreas seguras para la colocación de portales artroscópicos estándar de hombro: un estudio anatómico

The abundant vascular structures that surround the shoulder joint are complex and variable, complicating arthroscopy approaches. The aim of this study is to determine safe and risky areas around standard posterior and standard anterior portals, and accounting for the distribution of neurovascular structures of small and medium diameters that can lead to intra-articular bleeding during surgery. The standard posterior portal, and standard anterior portal were placed as described in the literature, and punch dissection was performed 2.5 cm around the trocar in situ. The arrangement of each identified structure was photographically documented and digitalized for each anatomic plane; the distance to the trocar and the diameter of each structure were measured. Based on each digitalized anatomic plane, safe and risky tissue areas were determined, and a clock face coordinate system was used to represent these areas. The safe area around the standard posterior portal was located between 11 and 1 o´clock for the left shoulder and 11 and 2 o´clock for the right shoulder. For the standard anterior portal, the safe area was located between 2 and 3 o´clock for the left shoulder and between 9 and 12 o´clock for the right shoulder. However, we did document a risk of injuring the cephalic vein 5 times, the axillary artery 3 times and the deltoid branch of the thoracoacromial artery once. This study reports quantitatively the total number of small diameter structures present in the two shoulder arthroscopic portals evaluated. The safe areas proposed in this study must be evaluated to propose new access points for performing arthroscopic procedures on the shoulder.

Las abundantes estructuras vasculares que rodean la articulación del hombro son complejas y variables, y dificultan los abordajes artroscópicos. El objetivo del estudio fue determinar áreas seguras y en riesgo en relación al portal posterior estándar y el portal anterior estándar y cuantificar la distribución de estructuras de diámetro pequeño e intermedio que puedan conducir a sangrado intraarticular durante la cirugía. El portal posterior estándar y el portal anterior estándar fueron colocados según su descripción en la literatura y fueron realizadas disecciones en sacabocado de 2,5 cm alrededor del trocar in situ. La disposición de cada estructura identificada fue documentada fotográficamente y digitalizada para cada plano anatómico. La distancia hacia el trocar y el diámetro de cada estructura fueron medidos. Basado en cada plano anatómico digitalizado, áreas de seguridad y riesgo tisular fueron determinadas y un sistema de coordenadas de manecillas de reloj fue utilizado para representar estas áreas. El área segura alrededor del portal posterior estándar fue localizada entre las 11 y las 1 en el sistema de las manecillas del reloj para hombros izquierdos y entre las 11 y las 2 para hombros derechos. Para el portal anterior estándar, el área segura fue localizada entre las 2 y 3 horas para hombros izquierdos y entre las 9 y 12 horas para hombros derechos. Aun así, se documentó el riesgo de lesionar la vena cefálica en 5 ocasiones, la arteria axilar en 3 ocasiones y la rama deltoidea de la arteria toracroacromial en una ocasión. Este estudio reporta cuantitativamente el número total de estructuras de pequeño diámetro presentes en los dos portales artroscopicos evaluados. Las áreas seguras propuestas en este estudio deben ser evaluadas para proponer nuevos puntos de acceso para la realización de procedimientos artroscopicos en el hombro.

PM(2.5) Characterization for Time Series Studies: Organic Molecular Marker Speciation Methods and Observations from Daily Measurements in Denver.

Particulate matter less than 2.5 microns in diameter (PM(2.5)) has been shown to have a wide range of adverse health effects and consequently is regulated in accordance with the US-EPA's National Ambient Air Quality Standards. PM(2.5) originates from multiple primary sources and is also formed through secondary processes in the atmosphere. It is plausible that some sources form PM(2.5) that is more toxic than PM(2.5) from other sources. Identifying the responsible sources could provide insight into the biological mechanisms causing the observed health effects and provide a more efficient approach to regulation. This is the goal of the Denver Aerosol Sources and Health (DASH) study, a multi-year PM(2.5) source apportionment and health study.The first step in apportioning the PM(2.5) to different sources is to determine the chemical make-up of the PM(2.5). This paper presents the methodology used during the DASH study for organic speciation of PM(2.5). Specifically, methods are covered for solvent extraction of non-polar and semi-polar organic molecular markers using gas chromatography-mass spectrometry (GC-MS). Vast reductions in detection limits were obtained through the use of a programmable temperature vaporization (PTV) inlet along with other method improvements. Results are presented for the first 1.5 years of the DASH study revealing seasonal and source-related patterns in the molecular markers and their long-term correlation structure. Preliminary analysis suggests that point sources are not a significant contributor to the organic molecular markers measured at our receptor site. Several motor vehicle emission markers help identify a gasoline/diesel split in the ambient data. Findings show both similarities and differences when compared with other cities where similar measurements and assessments have been made.