EP-4739261-A1 - METHOD AND SYSTEM FOR CATARACT TISSUE SENSING

Abstract

Systems and methods for sensing tissue in a phacoemulsification procedure are provided herein. A method may include generating a sensing signal through a frequency range centered at a local resonant frequency of an ultrasonic handpiece and measuring impedance characteristics of the signal at a distal end of a needle of an ultrasonic handpiece. A method may further include comparing the measured impedance characteristics of the generated sensing signal with one or more stored impedance profiles. A method may further include classifying, based on the comparison between the measured impedance characteristics and the stored one or more impedance profiles, a medium contacting the distal end of the needle. A method may further include controlling an output of the ultrasonic handpiece based on the classification of the medium contacting the tip of the needle.

Inventors

• WAID, Christopher
• NOTT, Cameron
• LIEU, KATRINA

Assignees

• Johnson & Johnson Surgical Vision, Inc.

Dates

Publication Date

20260513

Application Date

20240627

Claims (20)

1. 1. A system for use in a phacoemulsification procedure comprising: a console comprising a processor and a memory device; and an ultrasonic handpiece comprising a needle a coupled with a distal end of the ultrasonic handpiece, wherein the needle comprises a distal end and wherein the ultrasonic handpiece is coupled with the console; the processor configured to generate a sensing signal through a frequency range centered at a local resonant frequency of the ultrasonic handpiece; the processor configured to measure impedance characteristics of the signal at the distal end of the needle; the processor configured to compare the measured impedance characteristics of the generated sensing signal with one or more impedance profiles stored in the memory device; the processor and the memory device configured to classify, based on the comparison between the measured impedance characteristics and the stored one or more impedance profiles, a medium contacting the distal end of the needle; and the processor configured to control an output of the ultrasonic handpiece based on the classification of the medium contacting the distal end of the needle.
2. 2. The system of claim 1, wherein the measured impedance characteristics comprise impedance magnitude and impedance phase measurements.
3. 3. The system of claim 1, wherein the processor is configured to classify the medium contacting the distal end of the needle using a machine learning algorithm.
4. 4. The system of claim 1, wherein the processor is configured to compare the measured impedance characteristics of the generated sensing signal with one or more impedance profiles stored in the memory device by calculating deviation values at a plurality of frequencies of the frequency range between the measured impedance characteristics and the one or more stored impedance profiles, wherein the processor is configured to calculate a sum, for each stored impedance profile, of the deviation values at the plurality of frequencies, and to classify the medium contacting the distal end of the needle based on the impedance profile corresponding to the lowest calculated sum.
5. 5. The system of claim 1, wherein the processor is configured to classify the medium contacting the distal end of the needle as one of cataract or non-cataract material.
6. 6. The system of claim 1, wherein, on a condition the medium contacting the distal end of the needle is classified as non-cataract, the processor is configured to control an output of the ultrasonic handpiece by ceasing delivery of ultrasonic power or by preventing delivery of ultrasonic power.
7. 7. The system of claim 1 , wherein the processor is configured to classify the medium contacting the distal end of the needle based on a diameter or gauge of the distal end of the needle.
8. 8. The system of claim 3, wherein the machine learning algorithm uses, to classify the medium contacting the distal end of the needle, one or more of: a Fuzzy K-Means model, a Support Vector Machine (SVM) model, a Random Forest model, a Nearest Neighbors model, or a Logistic Regression model.
9. 9. The system of claim 1, wherein the processor is configured to adjust a sensitivity level to be used in classifying the medium contacting the distal end of the needle in response to a user input received at a user interface.
10. 10. The system of claim 1, wherein the processor is configured to determine, based on the classified medium contacting the distal end of the needle, based on aspiration flow data, and based on vacuum pressure data, that an occlusion is present at the distal end of the needle.
11. 11. A method for sensing tissue during a phacoemulsification procedure, the method comprising: generating a sensing signal through a frequency range centered at a local resonant frequency of an ultrasonic handpiece, wherein the ultrasonic handpiece comprises a needle coupled with the distal end of the ultrasonic handpiece; measuring impedance characteristics of the signal at a distal end the needle; comparing the measured impedance characteristics of the generated sensing signal with one or more stored impedance profiles; classifying, based on the comparison between the measured impedance characteristics and the stored one or more impedance profiles, a medium contacting the distal end of the needle; and controlling an output of the ultrasonic handpiece based on the classification of the medium contacting the distal end of the needle.
12. 12. The method of claim 11, wherein the measured impedance characteristics comprise impedance magnitude and impedance phase measurements.
13. 13. The method of claim 11, further comprising classifying the medium contacting the distal end of the needle using a machine learning algorithm.
14. 14. The method of claim 12, further comprising comparing the impedance characteristics of the generated sensing signal with one or more impedance profiles stored in the memory device by calculating deviation values at a plurality of frequencies of the frequency range between the measured impedance characteristics and the one or more stored impedance profiles; and calculating a sum, for each stored impedance profile, of the deviation values at the plurality of frequencies, and classifying the medium contacting the distal end of the needle based on the impedance profile corresponding to the lowest calculated sum.
15. 15. The method of claim 11, further comprising classifying the medium contacting the distal end of the needle as one of cataract or non-cataract material.
16. 16. The method of claim 11, wherein, on a condition the medium contacting the distal end of the needle is classified as non-cataract, controlling an output of the ultrasonic handpiece by ceasing delivery of ultrasonic power or by preventing delivery of ultrasonic power.
17. 17. The method of claim 11, further comprising classifying the medium contacting the distal end of the needle based on a diameter or gauge of the distal end of the needle.
18. 18. The method of claim 13, wherein the machine learning algorithm uses, to classify the medium contacting the distal end of the needle, one or more of: a Fuzzy K-Means model, a Support Vector Machine (SVM) model, a Random Forest model, a Nearest Neighbors model, or a Logistic Regression model.
19. 19. The method of claim 11, further comprising adjusting a sensitivity level to be used in classifying the medium contacting the distal end of the needle in response to a user input received at a user interface.
20. 20. The method of claim 11, further comprising determining, based on the classified medium contacting the distal end of the needle, based on aspiration flow data, and based on vacuum pressure data, that an occlusion is present at the distal end of the needle.

Description

METHOD AND SYSTEM FOR CATARACT TISSUE SENSING CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Patent Application No. 18/349047, filed on July 7, 2023, the entire contents of which are hereby incorporated by reference. FIELD OF INVENTION [0002] This invention generally relates to surgical devices used in ocular surgery and more specifically to hand-held ultrasonic devices for use in phacoemulsification procedures. BACKGROUND [0003] One objective of cataract surgery is to remove a patient’s clouded lens by fragmenting and emulsifying the lens and extracting the emulsified lens so that it can be replaced with an artificial lens. This process, phacoemulsification, is accomplished through the use of an ultrasonic handpiece. The ultrasonic handpiece includes a needle having a distal end with an aspiration port connected via tubing to a phacoemulsification console. After the needle is inserted into a patient’s eye, vacuum pressure induced within the aspiration tubing causes material within the eye to be aspirated through the needle. The ultrasonic handpiece is also fitted with irrigation tubing through which sterile irrigation fluid travels from the console and into the eye, replacing volumes of fluid and material in the eye that are lost due to aspiration and leakage. The distal end of the needle is configured to vibrate at an ultrasonic frequency, which, when in contact with tissue of the eye, may cut through and break apart the cataract into smaller pieces that can more easily be aspirated through tubing within the handpiece. [0004] In the anatomy of the eye, the lens is separated from the interior of the eye by the lens capsule. The lens capsule may need to remain intact because it forms a barrier between the aqueous chamber and the vitreous chamber of the eye. If the lens capsule is broken, it must be repaired, which may lengthen and complicate the procedure. [0005] Using existing methods for phacoemulsification, the lens capsule may become damaged due to human error. For example, a surgeon may cut through the lens capsule if the tip of the ultrasonic handpiece accidentally touches the lens capsule while ultrasonic power is activated. This may occur because the lens capsule sits directly behind the lens, and the surgeon may inadvertently continue to supply ultrasonic power after the cataract occlusion has been broken up and aspirated. Ideally, the surgeon would activate ultrasonic power only when the tip of the handpiece is touching the cataract. SUMMARY [0006] Systems and methods for sensing tissue in a phacoemulsification procedure are provided herein. A method may include generating a sensing signal through a frequency range centered at a local resonant frequency of an ultrasonic handpiece and measuring impedance characteristics of the signal at a distal end of a needle of an ultrasonic handpiece. A method may further include comparing the measured impedance characteristics of the generated sensing signal with one or more stored impedance profiles. A method may further include classifying, based on the comparison between the measured impedance characteristics and the stored one or more impedance profiles, a medium contacting the distal end of the needle of the ultrasonic handpiece. A method may further include controlling an output of the ultrasonic handpiece based on the classification of the medium contacting the distal end of the needle of the ultrasonic handpiece. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 is an anatomical illustration of a human eye; [0008] FIG. 2 illustrates a comparison between a healthy human eye having a clear lens and an eye in which a cataract has formed; [0009] FIG. 3 illustrates a comparison between the operation of a lens of a normal human eye and the operation of a lens of an eye in which a cataract has formed; [0010] FIG. 4 is a schematic, pictorial illustration of an example of a phacoemulsification system; [0011] FIG. 5 is an example of a two-dimensional representation of an impedance profile generated when a needle is in contact with air; [0012] FIG. 6 is an illustration depicting finite element analysis (FEA) simulations of an ultrasonic handpiece; [0013] FIG. 7 is a plot illustrating frequency and impedance magnitude information, where frequency information is plotted along the x-axis and impedance magnitude (“Z magnitude”) information is plotted along the y-axis; [0014] FIG. 8 is a plot illustrating frequency and impedance phase information, where frequency information is plotted along the x-axis and impedance phase (“Z Phase”) information is plotted along the y-axis; [0015] FIG. 9 is a plot illustrating impedance phase and magnitude information, where impedance phase information (“Z Phase”) is plotted along the x-axis and impedance magnitude information is plotted along the y-axis; [0016] FIG. 10 illustrates an example of a three-dimensional plot of impedance measurement data associated with master profiles for air,