Methods and apparatus are provided for selective surgical removal of tissue, e.g., for enlargement of diseased spinal structures. The current invention includes specific tools that enable safe tissue modification in epidural space, including a barrier that separates the area where tissue modification will take place from adjacent vulnerable neural and vascular structures. In one variation, a tissue abrasion device is provided including a thin belt or ribbon with an abrasive cutting surface. The device optionally may be placed within a protective sheath that exposes the abrasive surface of the ribbon only in the area where tissue removal is desired.