Intraoperative adjustment of a pre-operatively planned implant cavity to improve implant fit

Patent metadata

Field	Value
Publication number	US-11259872-B2
Application number	US-201916521672-A
Country	US
Kind code	B2
Filing date	Jul 25, 2019
Priority date	Jul 25, 2018
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

A method and system are provided to intraoperatively adjust the dimensions of a pre-operatively planned implant cavity to improve implant fit in a bone. The method includes obtaining a preoperative image data set of the bone. A surgical plan is generated using the image data set and/or a three-dimensional (3-D) bone model of the patient's bone generated from the image data set. Intraoperatively, the patient's bone is exposed and registered to the surgical plan and a computer assisted surgical system. The computer assisted surgical system having a cutting tip and a force sensor for sensing actual forces exerted on the cutting tip as an initial cut is created on the bone at a first bone region. Based on the difference between the actual cutting force and the expected cutting force in the plan, the dimensions of the cavity are adjusted accordingly.

First claim

The invention claimed is:

1. A method to intraoperatively adjust the dimensions of a pre-operatively planned implant cavity to improve implant fit, the method comprising:
obtaining an image data set of a bone;
generating a surgical plan using the image data set, the surgical plan comprising: (i) one or more expected cutting forces or cutting temperatures for one or more bone regions; and (ii) a location for the pre-operatively planned implant cavity to receive an implant in a predetermined position and orientation (POSE);
registering the surgical plan to the bone in a coordinate system of a computer assisted surgical system;
measuring an actual cutting force or cutting temperature on a cutting instrument while cutting a first bone region;
comparing the actual cutting force or cutting temperature to the one or more expected cutting forces or cutting temperatures; and
adjusting a dimension of the cavity based on the comparing to improve implant fit.

2. The method of claim 1 wherein the computer assisted surgical system further comprises a force sensor that measures the actual cutting force on the cutting instrument.

3. The method of claim 1 wherein if the actual cutting force is less than the one or more expected cutting forces, the dimension of the cavity is decreased.

4. The method of claim 1 wherein if the actual cutting force is more than the one or more expected cutting forces, the dimension of the cavity is increased.

5. The method of claim 1 wherein the computer assisted surgical system further comprises a thermocouple that measures the actual temperature on the cutting instrument.

6. The method of claim 1 wherein the image data set of the bone is obtained using an imaging modality comprising one of: computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, dual-energy X-ray absorptiometry (DEXA), X-Ray, or fluoroscopy.

7. The method of claim 1 wherein the image data set of the bone is obtained by probing an exposed portion of the bone with a tracked device to generate a 3-D point cloud of the bone.

8. The method of claim 1 wherein the image data set of the bone comprises bone quality data associated with the one or more bone regions.

9. The method of claim 8 wherein the bone quality data is measured as a function of bone density, architecture, composition, or a combination thereof.

10. The method of claim 8 wherein the bone quality data is a relative value with respect to the bone itself, or absolute values relative to a known or standard scale.

11. The method of claim 8 wherein the bone quality data is provided as Hounsfield units.

12. The method of claim 8 wherein the bone quality data is provided as T-Scores or Z-scores from dual-energy X-ray absorptiometry imaging.

13. The method of claim 8 wherein the bone quality data is further correlated to cutting force data to generate the one or more expected cutting forces at the one or more bone regions.

14. The method of claim 1 wherein the surgical plan is generated by a planning software program.

15. The method of claim 14 wherein the planning software generates a three-dimensional (3D) model of the bone; and
wherein the planning software further comprises widgets and other tools to allow a user to position pre-loaded implant models relative to the 3-D bone model to determine a POSE of the pre-operatively planned implant cavity.

16. The method of claim 1 wherein the computer assisted surgical system generates a notification to inform a user that the actual cutting force differs from the one or more expected cutting forces.

17. The method of claim 16 wherein the actual cutting forces are compared to the expected cutting forces for several bone regions prior to notifying, instructing, or automatically determining cavity adjustments.

18. The method of claim 16 wherein the comparing occurs in real-time for several bone regions while cutting the cavity, where the cutting instrument is paused to notify, instruct, or automatically determine cavity adjustments only when encountering a threshold difference between the actual and expected cutting forces.

19. The method of claim 16 wherein the computer assisted surgical system provides cavity adjustment recommendations or automatically determines the cavity adjustment based on historical data and machine learning; and
storing for each patient case, the size of the cavity, bone quality data, and clinical outcomes to build a model correlating cavity size, bone quality data, and clinical outcomes to determine cavity adjustments for a present patient case.

Assignees

• Think Surgical Inc

Inventors

• Forstein Micah

Classifications

• A61B34/30 Primary

  Surgical robots · CPC title

• A61B2034/107

  Visualisation of planned trajectories or target regions · CPC title

• A61B17/16

  Instruments for performing osteoclasis; Drills or chisels for bones; Trepans {(arthroscopic bone cutters A61B17/320016)} · CPC title

• A61B2034/2051

  Electromagnetic tracking systems · CPC title

• A61B34/10 Primary

  Computer-aided planning, simulation or modelling of surgical operations · CPC title