EP-4740878-A2 - SURGICAL SYSTEMS FOR DETERMINING BREAKTHROUGH DEPTH OF CUTTING TOOLS

Abstract

A surgical system for determining breakthrough depth of a bore in a bone passing through a proximal cortical layer of bone and a distal cortical layer of bone. The surgical system includes an instrument for coupling to a cutting tool. A sensor is coupled to the instrument to generate one or more depth measurements of the cutting tool as the cutting tool cuts through the bone. The breakthrough depth is determined based on depth measurements made after the cutting tool passes through the proximal cortical layer of bone. The breakthrough depth is optionally based on a type of bone being cut, bone hardness, and cutting tool selection.

Inventors

• SHARMA, RAHUL
• LAMBERT, Trevor, Jonathan

Assignees

• STRYKER CORPORATION

Dates

Publication Date

20260513

Application Date

20211118

Claims (10)

1. A surgical system for cutting into a bone with a cutting tool, the surgical system comprising: a first sensor configured to output one or more displacement signals associated with a displacement of the cutting tool during a cutting process; and a controller configured to, determine a proximal cortex acceleration event value of the cutting tool after the cutting tool advances to a depth corresponding to a depth threshold value, determine a proximal cortex acceleration event depth value based on a time at which the proximal cortex acceleration event value occurs, determine a plunging speed value of the cutting tool after the cutting tool advances from a reference point to the depth corresponding to the proximal cortex acceleration event depth value, wherein the plunging speed value is based on a velocity of the cutting tool from the reference point to the depth corresponding to the proximal cortex acceleration event depth value, determine a bone hardness factor based on the proximal cortex acceleration event value and the plunging speed value, and determine a breakthrough depth of a bore based on the bone hardness factor.
2. The surgical system of claim 1, further comprising an instrument and a measurement module configured to be coupled to the instrument, the measurement module comprising the first sensor.
3. The surgical system of claim 2, further comprising a second sensor, and wherein the instrument comprises a motor configured to receive electrical current to apply rotational torque to the cutting tool during a cutting process, and wherein the second sensor is configured to generate signals responsive to electrical current supplied to the motor of the instrument, and the controller is configured to determine a torque of the motor based on an output of the second sensor.
4. The surgical system of claim 3, wherein the instrument comprises an instrument housing and the measurement module comprises an attachment housing, and wherein the second sensor and the controller are disposed in the instrument housing, and wherein the first sensor is disposed in the attachment housing.
5. The surgical system of any one of claims 1 to 4, wherein controller is configured to determine acceleration data based on the displacement data.
6. The surgical system of any one of claims 1 to 5, wherein the depth threshold value is based on a type of bone being cut.
7. The surgical system of any one of claims 1 to 5, wherein the depth threshold value is based on an average proximal cortex thickness of a type of bone being cut.
8. The surgical system of any one of claims 1 to 7, wherein the reference point is established at the outer layer of the cortical bone.
9. The surgical system of any one of claims 1 to 8, wherein the first sensor comprises one or more sensors selected from a group consisting of a potentiometer, an optical sensor, and a linear variable displacement transformer.
10. The surgical system of any one of claims 1 to 9, wherein the cutting tool comprises one cutting tool selected from a group of cutting tools consisting of a drill bit, a blade, a bur, a saw, a rasp, a mill, a reamer, and a trocar pin.

Description

RELATED APPLICATIONS This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/115,590, filed on November 18, 2020, the entire contents of which are hereby incorporated by reference. BACKGROUND Conventional medical and surgical procedures routinely involve the use of surgical tools and instruments which allow surgeons to approach and manipulate surgical sites. By way of non-limiting example, rotary instruments such as handheld drills are commonly utilized in connection with orthopedic procedures to address various musculoskeletal conditions, such as trauma, sports injuries, degenerative diseases, joint reconstruction, and the like. In procedures where handheld drills or similar surgical instruments are employed, rotational torque selectively generated by an actuator (e.g., an electric motor) is used to rotate a releasably-attachable drill bit or other surgical attachments at different speeds. A surgical handpiece assembly drills bores in the tissue against which the drill bit is applied. One type of surgical procedure in which it is necessary to drill a bore is a trauma procedure to repair a broken bone. In this type of procedure, an elongated rod, sometimes called a nail, is used to hold the fractured sections of the bone together. To hold the nail in place, one or more bores are driven into the bone. These bores are positioned to align with complementary holes formed in the nail. A screw is inserted in each aligned bore and nail hole. The screws hold the nail in the proper position relative to the bone. In another type of procedure, an implant known as a plate is secured to the outer surfaces of the fractured sections of a bone to hold the sections together. Screws hold the plate to the separate sections of bone. To fit a screw that holds a plate to bone it is necessary to first drill a bore to receive the screw. As part of a procedure used to drill a screw-receiving bore in a bone, it is desirable to know the depth of the bore. This information allows the surgeon to select size of screw that is fitted in the bore hole. Accordingly, an integral part of many bone bore-forming procedures is the measuring of the depth of the bore. Currently, this measurement is often taken with a depth gauge separate from the drill. This requires the surgeon to, after withdrawing the drill bit from the bore, insert the depth gauge into the bore. Then, based on tactile feedback, the surgeon sets the gauge so the distal end of the gauge only extends to the far opening of the bore. Once these processes are complete, the surgeon reads the gauge to determine the depth of the bore. It is desirable to identify methods and apparatus that improve these devices and methods. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is perspective view of a surgical system comprising a surgical instrument and end effector, the end effector shown having a drill bit having an identification feature and a tip protector according to one configuration.Figure 2 is a partially exploded perspective view of the surgical system of Figure 1, with the surgical instrument shown having a measurement module, a drive assembly, and a release mechanism spaced from a handpiece body, and with the end effector removed from the surgical instrument and shown with the tip protector spaced from a distal cutting tip portion of the drill bit.Figure 3 is a partial isometric sectional view taken along line 3-3 in Figure 1 illustrating the arrangement of the identification feature and the sensor located within the measurement module.Figure 4 is a sectional view taken longitudinally through the surgical instrument of Figures 1-4 illustrating the arrangement of the identification feature and the sensor located within the measurement module.Figure 5A is a cross-sectional view of a small bone with a drill bit and depth measurement extension in a first position relative to the small bone.Figure 5B is a cross-sectional view of the small bone with the drill bit of Figure 5A and depth measurement extension in a second position relative to the small bone.Figure 5C is a cross-sectional view of the small bone with the drill bit of Figures 5A-5B and depth measurement extension in a third position relative to the small bone.Figure 6A is a cross-sectional view of a large bone with another drill bit and depth measurement extension in a first position relative to the large bone.Figure 6B is a cross-sectional view of the small bone with the drill bit of Figure 6A and depth measurement extension in a second position relative to the large bone.Figure 6C is a cross-sectional view of the small bone with the drill bit of Figures 6A-6B and depth measurement extension in a third position relative to the large bone.Figure 7 is a graphical representation of the displacement signal for a drilling process for two types of bones.Figure 8 is a graphical representation of the acceleration signal for a drilling process for two types of bones. SUMMARY With the scope of the