Device and Method For Instrument Adjustment in Computer Assisted Surgery

• US 20100286710A1
• Filed: 10/22/2009
• Published: 11/11/2010
• Est. Priority Date: 05/05/2009
• Status: Active Grant

• Current Assignee: Blue Ortho
• Original Assignee: Blue Ortho
• Inventors: Lavallee, Stéphane, BOYER, Anthony
• Granted Patent: US 9,168,106 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• CPC Class Codes: A61B 17/151 for corrective osteotomy
• CPC Class Codes: A61B 17/152 for removing a wedge-shaped piece of bone
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61B 17/157 Cutting tibia
• CPC Class Codes: A61B 17/17 Guides or aligning means for drills , mills, pins or wires
• CPC Class Codes: A61B 17/1707 using electromagnetic effects, e.g. with magnet and external sensors
• CPC Class Codes: A61B 17/1717 for applying intramedullary nails or pins
• CPC Class Codes: A61B 17/1725 for applying transverse screws or pins through intramedullary nails or pins
• CPC Class Codes: A61B 17/1739 specially adapted for particular parts of the body
• CPC Class Codes: A61B 17/1764 for the knee
• CPC Class Codes: A61B 17/8061 specially adapted for particular bones A61B17/70 and A61B17/74 take precedence
• CPC Class Codes: A61B 17/808 Instruments for holding or positioning bone plates, or for adjusting screw-to-plate locking mechanisms
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00057 Light
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2090/0811 for the position of a particular part of an instrument with respect to the rest of the instrument, e.g. position of the anvil of a stapling instrument
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis

Abstract

The present invention relates to a device for adjusting the position of a surgical instrument (1) with respect to a solid (3) tracked by a navigation system (2), wherein the instrument (1) comprises a fixed part (11) that is rigidly fixed to the solid (3) and a mobile part (12) that is attached to the fixed part by screws (13), said device (4) comprising:

• • a stem (41) comprising a tip (42) suited to the head (130) of the screws (13),
  • a motorized system (45) for driving said stem (41) in rotation,
  • communication means with the navigation system (2), such that the navigation systems (2) transmits to the motorized system (45) the number of turns to apply to the stem (41) to reach the target position of each screw (13).

Claims

1. A device for adjusting the position of a surgical instrument with respect to a solid tracked by a navigation system, wherein the instrument comprises a fixed part that is rigidly fixed to the solid and a mobile part that is attached to the fixed part by screws, said device comprising:

a stem comprising a tip suited to the head of the screws,

a motorized system for driving said stem in rotation,

communication means with the navigation system, such that the navigation systems transmits to the motorized system the number of turns to apply to the stem to reach the target position of each screw.

2. The device of claim 1, further comprising detection means for identifying which screw the tip of the device is in contact with, wherein the communication means of the device are able to transmit said identification information to the navigation system.

3. The device of claim 2, wherein said detection means comprise a sliding stem able to slide inside the stem and a position sensor adapted to measure the displacement of the sliding stem with respect to the tip of the device.

4. The device of claim 2, wherein the detection means comprise electrical connectors arranged at the tip of the device and an ohmmeter.

5. The device of claim 2, wherein the detection means comprise a “

Hall effect”

sensor arranged in the tip of the device.

6. The device of claim 2, wherein the detection means comprise an optical sensor, a first optical fiber and a second optical fiber, the first and second optical fibers being arranged inside the stem so as to respectively light the cavity of the screw head and bring the reflected light to said optical sensor.

7. The device of claim 2, wherein the detection means comprises a tracker rigidly attached to the device.

8. A method of adjusting the position of a surgical instrument with respect to a solid, tracked by a navigation system, wherein the instrument comprises a fixed part that is rigidly fixed to the solid and a mobile part that is attached to the fixed part by screws, comprising the following steps:

determining the position of the mobile part of the instrument with respect to the solid,

comparing said determined position with respect to a target position,

if said determined position is different from the target position, computing, for each screw of the instrument, the number of turns to apply in order to reach said target position,

positioning the tip of the device according to one of claims 1 to 7 in each screw head,

operating the motorized system of the device such that it applies to the stem the computed number of turns.

9. The method of claim 8, wherein the solid is a tibia or a femur, the surgical instrument is a cutting block with a cutting plane and three screws assembled in a parallel architecture are used for adjustment of the plane.

10. A computer assisted surgical navigation system for adjusting the position of a surgical instrument with respect to a solid, wherein the instrument comprises a fixed part that is rigidly fixed to the solid and a mobile part that is attached to the fixed parts by screws, the system comprising:

a first reference element applied to the solid that generates a first three-dimensional dynamic reference tracker, which is independently registered in the navigation system

a second reference element applied to mobile part of the surgical instrument that needs to be adjusted, that generates a second three-dimensional dynamic reference tracker, which is independently registered in the navigation system

the device of one of claims 1 to 7

wherein the number of turns and the rotation direction are determined for each screw by the navigation system, taken into account the current mobile part position, the target mobile part position, the design of the screws and the design of the instrument, and transmitted to the device by the communication means.