Safe Areas for the Placement of Standard Shoulder Arthroscopy Portals. An Anatomical Study/Areas Seguras para la Colocacion de Portales Artroscopicos Estandar de Hombro. Un Estudio Anatomico

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. KEY WORDS: Anatomy; Arthroscopy; Portals; Safe Areas; Shoulder. Las abundantes estructuras vasculares que rodean la articulacion del hombro son complejas y variables, y dificultan los abordajes artroscopicos. El objetivo del estudio fue determinar areas seguras y en riesgo en relacion al portal posterior estandar y el portal anterior estandar y cuantificar la distribucion de estructuras de diametro pequeno e intermedio que puedan conducir a sangrado intraarticular durante la cirugia. El portal posterior estandar y el portal anterior estandar fueron colocados segun su descripcion en la literatura y fueron realizadas disecciones en sacabocado de 2,5 cm alrededor del trocar in situ. La disposicion de cada estructura identificada fue documentada fotograficamente y digitalizada para cada plano anatomico. La distancia h