An exoskeleton device is capable of being positioned over an expandable instrument, such as a balloon catheter. The exoskeleton device may include an expandable section that receives an expander of the expandable instrument. Expansion of the expander may cause the expandable section of the exoskeleton device to expand and force the expandable section of the exoskeleton device against a surface to be treated. The expandable section may be capable of scoring the surface against which it is forced.
