An instrument for cutting bone includes a hollow shaft having a sidewall. A cutting element is at least partially housed in the hollow shaft. The cutting element can include one or more cutting blades that are radially expandable through the sidewall. The instrument can also include a piercing tip on a distal end of the hollow shaft is located distally of the one or more cutting blades. In addition, the instrument can include an expansion element for radially expanding the one or more cutting blades through the sidewall.
