CAS bone reference and less invasive installation method thereof

A surgical bone reference assembly communicable with an image guided surgical system such that position and movement of a bone clement are monitorable, the bone reference assembly comprising:

• a bone anchor member comprising a trackable member and teeth engageable with the bone element, the trackable member comprising a detectable element adapted to be located and tracked in three dimensional space by the image guided surgical system, thereby defining position and movement of the trackable member;
• and
• a protective guide member for use with the bone anchor member such that the bone anchor member is in is through soft tissue covering the bone element without causing significant damage thereto;
• the bone anchor member being engageable with the bone element, such that the teeth are forced into engagement with the bone element and the bone anchor member is fastenable to the bone element in a fixed relation thereto.

A surgical bone reference assembly communicable with a computer assisted surgical (CAS) system such that position and movement of a bone element are monitorable, the bone reference assembly comprising:

• a bone anchor member comprising a trackable member and teeth engageable with the bone element, the trackable member comprising a detectable element adapted to be located and tracked in three dimensional space by the CAS system, thereby defining position and movement of the trackable member;
• and
• a protective member for use with the bone anchor member such that the teeth of the bone anchor member insertable through soft tissue covering the bone clement without causing significant damage thereto;
• the bone anchor member being engageable with the bone element such that the teeth are forced into engagement with the bone element and the bone anchor member is fastenable to the bone element in a fixed relation thereto.

A method for monitoring position and movement of a bone element using an image guided surgical system, comprising the steps of:

• providing a bone reference assembly comprising a bone anchor member having at least three bone engaging teeth, a bone anchor screw and a trackable member, the trackable ember comprising a detectable element adapted to be located and hacked in three dimensional space by the image guided surgical system, thereby defining position and movement of the trackable member;
• inserting the bone anchor member through soft tissue covering the bone element until at least a part of the bone anchor member is in direct engagement with the bone element, while protecting the soft tissue from said teeth and gradually separating the soft tissue so as not to cause significant damage thereto;
• engaging the bone element with e bone anchor screw and the teeth such that the bone reference assembly in a fixed position relative to the bone element;
• performing a registration of the bone element;
• and locating and tracking the bone element using the image guided surgical system.