Abstract: Provided are methods for accessing tissue in the vicinity of a blood vessel. Also provided are devices for use in a lumen of a patient's organ and methods for shunting interior volumes of organs.

Abstract: A retractor with devices that allow a surgeon to control the amount of retractor force. The retractor may include a first blade and a second blade. The second blade can be moved by a gear mechanism. A torque measuring device, force measuring device and/or slip clutch may be coupled to the gear mechanism. The torque measuring device may have a readout that displays the amount of torque being applied by the surgeon to the retractor. The readout provides accurate feedback that allows the surgeon to gauge the amount of force being applied to the patient. Likewise the force measuring device may provide a visual indication of the actual force being applied by the retractor onto the patient. The slip clutch may actuate at a threshold torque to prevent an excessive exertion of force on a patient.