Methods and devices for separating an implanted object, such as a pacemaker lead, from tissue surrounding such object in a patient's vasculature system. Specifically, the surgical device includes a handle, an elongate inner sheath and a circular cutting blade that extends from the distal end of the sheath upon actuating the handle. The circular cutting blade is configured to engage the tissue surrounding an implanted lead and cut such tissue in a coring fashion as the surgical device translates along the length of the lead, thereby allowing the lead, as well as any tissue remaining attached to the lead, to enter the device's elongate shaft. The surgical device has a barrel cam cylinder in the handle assembly that imparts rotation of the blade and a separate cam mechanism in the tip of outer sheath assembly that imparts and controls the extension and retraction of the blade. The barrel cam cylinder and cam mechanism cooperate to cause the blade to rotate in a first direction and extend from and retract in the outer sheath due to a first actuation of the handle and to rotate in a second direction and extend and retract in the outer sheath due to a second actuation of the handle. The inner sheath and outer sheath are constructed of laser-cut hypotubes, thereby allowing the surgical device, particularly the sheath assembly, to have a smaller profile for navigating smaller sized vasculature.