The present invention comprises devices for treating a body structure. An embodiment of the invention comprises a device (200) for controlled fluid pressure flow of a fluid to a body structure, comprising: a first exit port (230)； a first container (204a) for air and a second container (204b) for liquid, each container in fluid connection with the first exit port (230)； two elements (207a, 207b) for moving the air/liquid from the first container (204a) and the second container (204b) toward the first exit port (230)； and a pressure relief valve (221b) that opens at a predetermined pressure, wherein the pressure relief valve (221b) is in fluid connection between the exit port (230) and the first and second containers (204a, 204b), such that when the predetermined pressure is exceeded, the relief valve (221b) opens and air/liquid flows through a second exit port (217).
