Abstract: An apparatus is disclosed for use with a surgical navigation system. The apparatus comprises a tool body and tool attachment onto which emitters are fixedly mounted. At least one tool tip is removably coupled with the tool body. An electrical sensor is positioned to be operated when the tool tip is changed either by coupling the tip to or removing the tip from the tool body. A controller responsive to the operation of switch detects when the tip has been changed. An alarm responsive to the controller indicates that the tool tip has been removed or changed so that the tip can be recalibrated relative to a known position in the surgical navigation system.

Abstract: An adjustable guide for a rotary tool shaft adapted to penetrate a work-piece, the tool shaft connected to a motor having a housing. The adjustable guide including a base connected to the housing and the base having a series of threads. A stop is threadedly engaged with the threads of the base and axially adjustable with respect to the base by rotational movement about the base. A guide tube is slidably connected to the base and is limited in its movement by engagement with the stop. An indexed locking mechanism interengages the base and the stop to lockingly prevent rotation of the stop about the base at pre-set intervals, thereby axially displacing the stop a preset discrete distance between each indexed interval. The stop controlling axial displacement of the guide tube and thereby controlling the depth of penetration of the rotary tool shaft into the work-piece.