Methods and devices are disclosed to reduce tissue trauma when a physician retracts a patient's tissues for surgery. A device includes a tissue engager adapted to engage a patient's tissue, a control system adapted to control the tissue engager to deform the patient's tissue, and a sensor adapted to produce a first signal based on a status of the tissue engager. The control system is operatively associated with a motive source and the sensor. The control system is configured to receive the first signal based on the status of the at least one tissue engager, and control, in light of the first signal based on the status of the at least one tissue engager, the at least one motive source in order to control the motion of the at least one tissue engager. The motion of the at least one tissue engager may be an oscillating motion.
