CAS modular body reference and limb position measurement system
First Claim
1. A surgical bone reference assembly, adapted for communication with a computer assisted surgical system, comprising:
- a bone anchor member, engageable to a bone element of a patient such that substantially no relative movement therebetween is possible;
a trackable member comprising a detectable element adapted to be located and tracked in three dimensional space by the computer assisted surgical system, thereby defining position and movement of said trackable member;
an adjustable support member having said trackable member disposed at a first end thereof, a second end of said support member being removably fastenable to said bone anchor member by an attachment member, said support member permitting variable positioning of said trackable member relative to said bone anchor member and being lockable to fix said trackable member in a desired position and orientation relative to said bone anchor member; and
said support member, via said attachment member, being intra-operatively detachable from said bone anchor member and subsequently re-fastenable thereto such that said trackable member is in said desired position and orientation relative to the bone element.
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Accused Products
Abstract
A surgical bone reference assembly for communication with a CAS system, comprises a bone anchor fastenable to a bone element, an adjustable support and a trackable member that is located and tracked in three dimensional space by the CAS system. The support is removably fastenable to the bone anchor member and permits variable positioning relative to the bone anchor member. The support is intra-operatively detachable from and re-fastenable to the bone anchor member. A method of using a CT-free CAS system for determining a change in position of an un-tracked target limb is also provided. The method comprises engaging the trackable bone reference member to another bone element, locating and digitizing a landmark on the target limb, digitizing the landmark again following joint reduction, and determining at least one of a post-joint reduction limb length discrepancy and a target limb medio-lateral offset.
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Citations
21 Claims
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1. A surgical bone reference assembly, adapted for communication with a computer assisted surgical system, comprising:
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a bone anchor member, engageable to a bone element of a patient such that substantially no relative movement therebetween is possible;
a trackable member comprising a detectable element adapted to be located and tracked in three dimensional space by the computer assisted surgical system, thereby defining position and movement of said trackable member;
an adjustable support member having said trackable member disposed at a first end thereof, a second end of said support member being removably fastenable to said bone anchor member by an attachment member, said support member permitting variable positioning of said trackable member relative to said bone anchor member and being lockable to fix said trackable member in a desired position and orientation relative to said bone anchor member; and
said support member, via said attachment member, being intra-operatively detachable from said bone anchor member and subsequently re-fastenable thereto such that said trackable member is in said desired position and orientation relative to the bone element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for monitoring position and movement of a bone element using a computer assisted surgical system comprising:
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fastening a bone anchor member to the bone element;
attaching an adjustable support member to said bone anchor member, said adjustable support member having a trackable member fixed thereto, said trackable member including a detectable element being locatable and trackable in three dimensional space by said computer-assisted surgical system;
adjusting said trackable member into a desired position and orientation relative to sensing elements of said computer-assisted surgical system;
locking said adjustable support member in place such that said trackable member is fixed in said desired position and orientation relative to sensing elements of said computer-assisted surgical system;
performing a registration of the bone element;
detaching said adjustable support member from said bone anchor member; and
re-fastening said adjustable support member to said bone anchor member, said trackable member being in said desired position and orientation without requiring readjustment and said bone element being locatable and trackable using said computer assisted surgical system without requiring re-registration of said bone element. - View Dependent Claims (15, 16, 17)
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18. A computed tomography (CT) free computer assisted surgery (CAS) system for determining a change in position of an un-tracked target limb undergoing orthopaedic surgery, comprising:
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a bone reference member trackable by said CAS system and engaged with a bone element distinct from said target limb;
means for locating said bone reference member and determining a base coordinate system relative thereto;
a digitizer, trackable by said CAS system, for performing a first and a second digitization of a landmark on said target limb;
means for determining pre-joint dislocation coordinates in said base coordinate system from said first digitization and post-joint reduction coordinates in said base coordinate system from said second digitization, and for determining longitudinal axis components and medio-lateral axis components of said pre-joint dislocation coordinates and said post-joint reduction coordinates; and
means for determining at least one of a post-joint reduction limb length discrepancy value and a target limb medio-lateral offset value, said post-joint reduction limb length discrepancy value being computed using said longitudinal axis components and said target limb medio-lateral offset value being computed using said medio-lateral axis components. - View Dependent Claims (19, 20, 21)
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Specification