Expanding a spinal canal by drilling a cylindrical passage in each pedicle of a vertebra, making a circumferential pedicle cut (osteotomy) through each pedicle from within the passage, separating each pedicle cut by inserting an implant into the passage to distract the pedicle cut (i.e., lengthen the pedicle) to expand the spinal canal, and securing each pedicle cut, allowing the vertebra to heal with the spinal canal expanded. The implant can include an outer sleeve, an inner bolt, and expandable flanges. The outer sleeve includes an upper and a lower portion, with the expandable flanges therein. Rotation of the inner bolt causes the upper and lower portions of the outer sleeve to separate, causing the pedicle cut to widen and the expandable flanges to radially extend into and stabilize the widened pedicle cut for expansion of the spinal canal.