The Tissue Plane

In recent times, terms such as ‘interfascial plane block’ and ‘fascial plane block’ have become common in describing regional anaesthesia blocks such as transversus abdominis plane (TAP), serratus anterior plane (SAP) and erector spinae plane (ESP). In fact, none of these names accurately describes the applied anatomy involved in each named technique, as the acronym is only one part of the anatomic jigsaw puzzle. The correct term is ‘tissue plane block’, which derives from surgical terminology. The tissue plane is not new to regional anaesthesia, as it has been the endpoint of ‘loss of resistance’ and ‘pop’ techniques for many decades. However, the game-changer is that now we can see the tissue plane courtesy of ultrasound. The purpose of this chapter is to review the history of the tissue plane in relation to its use in regional anaesthesia, and to see how ultrasound has further advanced the regional anaesthesiologist’s options in this regard. The chapter will also review how an understanding of tissue dynamics can further enhance our clinical results by manipulating the characteristics of the tissue plane.

Review of Applied Anatomy, Hemodynamics, and Endovascular Management of Ectopic Varices

Portal hypertension leads to the opening up of collateral pathways to bypass the occlusion or resistance in the portal system. Ectopic varices are formed by such collaterals at many various sites along the gastrointestinal tract other than the usual location, that is, gastroesophageal region. Early diagnosis of ectopic varices needs strong clinical suspicion and contrast-enhanced computed tomography scan as endoscopy may often fail to pinpoint a source. In contrast to gastric varices where the understanding of the disease, as well as endovascular management, is widely studied and documented, the same is not true for ectopic varices due to low incidence. Understanding the applied anatomy and hemodynamic classification is important to decide the most suitable therapy. Interventional radiological procedures are aimed at either decompressing the varices or obliterating them and depend on the patency of the portal system, underlying etiology, and local expertise.