| 摘要 |
A novel surgical router bit is disclosed which comprises a shaft having a distal end and a proximal end and an outer surface tapering outwardly from its distal end to its proximal end, at least one spiral cutting flute or groove formed in and extending along the length of the shaft from the distal end of the shaft to the proximal end of the shaft, with the at least one spiral cutting flute or groove having a planar floor which is inclined relative to the center axis of the router bit, wherein for each pitch of the at least one spiral cutting flute or groove, the distal end of the floor is level with the tapering outer surface of the shaft and the proximal end of the floor has a fixed depth relative to the tapering outer surface of the shaft so as to define a helical cutting edge of fixed height, and at least one straight cutting flute or groove formed in and extending along the length of the shaft from the distal end of the shaft to the proximal end of the shaft, the at least one straight cutting flute or groove having a fixed depth relative to the tapering outer surface of the shaft so as to define a straight cutting edge of fixed height, and the at least one straight cutting flute or groove being superimposed on and intersecting the at least one spiral cutting flute. Preferably the surgical router bit comprises a plurality of spiral cutting flutes or grooves arcuately spaced apart around the circumference of the shaft, and a plurality of straight cutting flutes or grooves arcuately spaced apart around the circumference of the shaft.
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