Negative pressure wound therapy systems are described that can prevent the retainment of wound fill material in a wound cavity during dressing changes. The negative pressure wound therapy system includes a removal device that can be used to lift the wound fill material out of a wound cavity and prevent fracture of the wound fill material and retainment of fragments of the material in the wound. The removal device can include fibers (e.g., a fibrous net) that can be retained between the wall of the wound cavity and the wound fill material, with the wall of the wound and the wound fill material retaining direct contact with one another to encourage healing of the wound according to the therapy treatment process.