Rhomboid Intercostal Sub Serratus Plane Block Versus Serratus Anterior Plane Block in Thoractomy

After the location will be confirmed through hydrodissection of 1 ml on the plane between the rhomboid major and the underlying intercostal muscles after confirming a negative aspiration via a a 22-gauge short bevel sonovisible needle (Spinocan, B. Braun Melsungen AG, Germany) using an in-plane technique then 10 ml of bupivacaine (concentration 0.25%) will be injected. and its spread will be manifested by the hydrodissection and widening of the plane visualized by ultrasound.

A linear US transducer (Phillips-Saronno Italy) was placed vertically 3 cm lateral to the midline to visualize back muscles: the trapezius above, the rhomboid major in the middle, and the erector-spinae muscle on the bottom, as well as the TPs with shimmering pleura in between.