Methods for limiting the movement of flowable material introduced into or between tissue layers of the human spine. The method can include inserting a member between tissue layers of the human spine. The member has a first configuration for insertion of the elongated member between tissue layers. The shape of the member is changed into a second configuration that defines a barrier that limits or directs the movement of flowable material. Flowable material is introduced to a selected location between the tissue layers and the barrier acts to limit or direct the movement of the flowable material.