Methods of manipulating cancellous bone within a vertebral body. A steerable assembly is directed through an access cannula such that a deflectable portion of the steerable assembly protrudes from the access cannula to within the vertebral body. The steering instrument is actuated from an operating tension mode in which a tension is placed on the control element of the steering instrument to a slack tension mode in which the tension on the control element is released. The steerable instrument may exert substantially zero lateral force on the deformable conduit in the slack tension mode. The steering instrument is moved relative to the deformable conduit positioned within the vertebral body. The steering instrument is actuated to move the steering instrument from the slack tension mode to the operating tension mode in which the deflectable portion may assume a curved configuration not substantially coaxial with a longitudinal axis of the access cannula.
