RU2807937C1 - Multifunctional wireless device with replaceable surgical instruments for measuring their orientation angles in space and forces and moments affecting them during neurosurgical operations - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: invention relates to devices and surgical instruments used in neurosurgery for work related to cutting holes in soft tissues, as well as installing or removing internal fixation devices. A wireless device for measuring orientation angles and determining the forces and moments acting on interchangeable surgical instruments during neurosurgical operations includes a hollow handle for manual operations containing a rechargeable battery for powering all electronic parts, a housing inside which is installed a six-axis inertial orientation sensor based on a gyroscope and an accelerometer, controller, signal processing module from a six-axis force and torque sensor and an external control board with a control button and LED. A six-axis force and moment sensor is attached to the end part of the body, on which a flange and a threaded removable holder with buttons are installed, allowing for quick change of surgical instruments during surgery. A six-axis force and moment sensor and a six-axis orientation sensor are connected to a controller in the housing, which, in turn, is connected via a wireless interface to the device control unit for wireless connection, control and reception of data by the user’s personal computer with the ability to record and display data in graphical, audio and light form with visual indication when the maximum specified manipulation parameters are exceeded.

EFFECT: obtaining quantitative data on the orientation angles in space of surgical instruments, forces and moments arising from the manipulation of surgical instruments during a neurosurgical operation.

1 cl, 12 dwg

Description

Field of technology to which the invention relates

The invention relates to the field of medical technology, namely to devices and surgical instruments used in neurosurgery for work related to cutting a hole in soft tissue, installing or removing internal fixation devices. For example, to perform operations of transpedicular fixation of the vertebrae, the following basic surgical instruments are used: an awl, a straight probe, a curved probe, a tap, devices for screwing in pedicle screws and nuts. This invention proposes the use of a six-axis inertial orientation sensor to determine the orientation angles of the device, then converting them into linear movement relative to the screw axis, based on the known thread parameters of a surgical instrument or screw-implant. Also, when a surgical instrument or screw-implant interacts with human tissue, a torque arises due to friction; the value of this moment allows us to indirectly assess the characteristics of the soft tissue. Combining these parameters into the dependence of the torque acting on a surgical instrument during surgical manipulation on the movement of this surgical instrument along the screwing axis (screw or tap) allows us to characterize the processes occurring in the patient’s soft tissue when forming a hole thread with a tap or when screwing in a screw. implant. The obtained data can be classified and used in further analysis of surgical procedures.

There are known patents for devices and surgical instruments for neurosurgical operations, aimed at using data on the orientation of the surgical instrument:

WO 2004/112610 A2 (06/09/2004) - a removable miniature device that measures the orientation of a surgical instrument using built-in microelectromechanical gyroscopes. The device is attached to the cylindrical part of the surgical instrument using straps. Orientation data is output to the built-in LED screen. This navigation device can be used with a very wide range of surgical instruments, but fastening to the body with straps is not sufficiently reliable, and the reliability of determining the orientation angles of the surgical instrument directly depends on the place and method of fastening this device. It is used in prosthetics of the lower extremities, for more precise control when using invasive surgical instruments and preparing soft tissue for implant installation.

WO 2020 219925 A1 (10/29/2020) - an autonomous, removable miniature device that measures the orientation of an object using a built-in accelerometer, gyroscope and magnetometer. The device is attached to a surgical instrument using screws and a special tripod; to signal the surgeon about ongoing processes, there is a small built-in LED screen and the ability to wire connect an external device. Data collection and processing is not provided. Used in assembly with various surgical devices: drill, endoscopic grasper, awl, tap, pedicle screwdriver. The purpose of the device is to display data on the orientation angles of the surgical instrument relative to the screwing axis.

US 2015 0201918 A1 (07/23/2015) - a manual medical device with the ability to change surgical instruments and incorporating various types of sensors, including an accelerometer and a gyroscope. To carry out surgical manipulations, an electric motor is built into the device, powered by a flexible wire; an inertial orientation sensor is used to compensate for deviations from the main axial direction of drilling, screwing or other manipulations. Receiving data onto a personal computer and their further processing is not provided. It is used for orthopedic surgeries for prosthetics of human lower extremities.

WO 2021/072061 A1 (08.10.2020) - a device installed in the handle of a neurosurgical awl used during transpedicular fixation operations. The device measures the angles of inclination of the surgical instrument relative to the axial and sagittal plane, allowing one to determine the optimal direction for screwing in the implant screw. Orientation is measured using built-in inertial orientation sensors (a combination of accelerometer and gyroscope). Orientation data is transmitted via the BLE wireless interface to a personal computer, and then the surgeon is notified of the current value of the orientation angle. This device is built into the handle of a transpedicular awl and cannot be used with other surgical instruments.

The previously presented devices determine the orientation of the surgical instrument in space, are autonomous and allow one to provide information or signal that the permissible angle of inclination of the device is exceeded during neurosurgical operations. But these devices are not equipped with force and moment sensors, so their scope is limited only to determining the orientation of the device and its adjustment by the surgeon.

There are known patents for medical devices with the ability to measure the force and moment acting on a surgical instrument during a neurosurgical operation:

RU 2462342 C2 (10.25.2007) - a system for assessing the force in a surgical manipulator for minimally invasive intervention using six-axis force and moment sensors acting on a surgical instrument during surgical procedures. This system does not have the ability to be used manually to collect and process data.

There are known patents for devices with the ability to simultaneously measure the orientation in space of a surgical instrument and the forces acting on it:

US 11135024 B2 (05.10.2021) - a flange for a medical robot, equipped with a six-axis sensor of forces and moments acting on a surgical instrument during surgical procedures and an inertial measurement module. The flange design is designed to reduce surgical instrument replacement time and maintain versatility for use with various types of medical manipulators. The disadvantage of this product is the lack of possible manual use by the surgeon and the inability to collect and analyze data on the surgical procedures performed.

WO 2018/144282 A1 (01/24/2018) - a stand-alone device for measuring the orientation of a surgical instrument and the forces acting on it during knee surgery. This device has several replaceable surgical instruments. The peculiarity of this device is that it displays data on measured values directly on the device body; orientation data is displayed on a small LED screen built into the end; force data is presented on a two-sided signal display. The disadvantage of this device is a single-axis force sensor, the absence of a processing system for subsequent visualization and use of data, the inability to use surgical instruments for transpedicular fixation (awl, tap, transpedicular screwdriver, etc.).

Patent RU 2736162 C2 (04/29/2019) was chosen as the closest analogue (prototype), this is a device with replaceable surgical instruments for measuring the forces and moments acting on them from interaction with patient tissues during neurosurgical operations. The device includes a handle for manual manipulations having a mount with a lock in the form of a button, an adapter flange for mounting a six-axis force and moment sensor, a six-axis force and moment sensor, and interchangeable surgical instruments mated with structural connections. However, this device does not have the ability to measure the orientation of the surgical instrument and data is obtained through a wired interface, which makes the surgeon’s work difficult. There is also no method for processing and integrating torque and linear motion data.

Disclosure of the invention

The proposed invention is aimed at solving the problem of measuring orientation angles in space of a surgical instrument, and the forces acting on it, and moments arising from the interaction of replaceable (replaceable) surgical instruments with human tissue.

The technical result is obtaining quantitative data on the orientation angles in space of surgical instruments, forces and moments arising from the manipulation of surgical instruments during a neurosurgical operation. The obtained data is processed using methods of mathematical statistics and

the result of these calculations is the dependence of the torque acting on the surgical instrument on the amount of movement along the screwing axis of the device during surgical manipulation of human soft tissue.

The stated problem is solved, and the stated technical result is achieved by the fact that in a multifunctional wireless (for the convenience of the surgeon) device for measuring orientation in space, as well as forces and moments acting on a surgical instrument, it is structurally based on a single handle, which has built-in: a six-axis sensor forces and moments to measure forces and moments, and a six-axis inertial orientation sensor (gyroscope and accelerometer) to measure the angles of orientation of the device in space. The data received from the sensors is transmitted via a wireless interface to a personal computer, where it is processed and presented in graphical form. The use of replaceable surgical instruments for neurosurgical manipulations is possible using a removable connection in which the surgical instrument is clamped using a push-button spring mechanism; a similar system is implemented in the nearest prototype (analog). Switching on and off occurs via a lever switch in the multifunctional device; switching on occurs before the start of surgical procedures and requires time to initialize the sensors (20 seconds).

The claimed technical solution allows, in contrast to the closest prototype, to determine the orientation of the surgical instrument in 3-dimensional space, not to interfere with the work of the surgeon (lack of wire) and to carry out further data processing to represent the dependence of the torque on the movement of the surgical instrument. Signaling that the permissible value of displacement, forces and moments is exceeded is possible thanks to the use of a data processing method. The data processing method includes three parts: converting data about the angle of rotation of the device, converting the angle of rotation into linear movement based on known thread parameters, and filtering torque values from illiquid data, the appearance of which is caused by the manual nature of using the device. To use the method, data is accumulated in a format convenient for mathematical operations, in this case the .csv and .xlsx format is used, each file contains information about the time period of the manipulation, the values of forces and moments in three-dimensional space (3 values for forces and 3 values for torque moments) and includes a quaternion (which completely describes the orientation of the device in three-dimensional space).

Brief description of drawings

The invention is illustrated by images, where:

Figure 1 shows the detailed internal structure of the handle of the multi-function wireless device,

Figure 2 shows the detailed internal structure of the multi-function wireless device housing,

Figure 3 shows the detailed internal structure of the end link of the multi-function wireless device,

Figure 4 shows a block diagram of the data processing system of a multifunctional device,

Figure 5 shows a photograph of a multifunctional device, a control unit, a set of interchangeable surgical instruments and a personal computer,

Figure 6 shows the operating algorithm of the controller software in a multifunctional device,

Figure 7 shows the operating algorithm of the device control unit software,

Figure 8 shows the operating algorithm of the human-machine interface software,

Figure 9 shows the user interface of the HMI software,

Figure 10 shows an algorithm for processing data on the orientation of the device, forces and moments acting on the surgical instrument,

Figure 11 (a) and (b) shows a graph of processing data about torque and movement of the device and a graph of torque versus movement.

The items shown in the images correspond to the following:

1. A cover with a thread that serves to protect the electronic components located in the handle from the influence of the external environment.

2. Nut with external thread, used to secure the power connector inside the handle.

3. The power connector installed in the handle of the multifunction device is used to charge the battery and transmit information to the controller of the multifunction device.

4. A sleeve to which the power connector is attached, for installation inside a hollow handle.

5. Power connector nut, which secures the power connector firmly in the handle of the multifunction device.

6. Spring for securing the battery motionlessly inside the handle of the multifunctional device.

7. The battery is installed in the handle and ensures autonomous operation of all electronic components of the multifunctional device.

8. Shell for the handle, which ensures minimal slippage and comfortable use of the multifunctional device during manual operations by the surgeon.

9. Connector for connecting a six-axis force and torque sensor to the signal conversion board of the multifunctional device.

10. Six-axis force and moment sensor, providing measurements of forces and moments acting on a surgical instrument during a neurosurgical operation.

11. The hollow handle, designed for manual manipulations performed by the surgeon, contains a battery and power connector.

12. Nuts installed in the grooves on the handle are used to firmly secure the circuit boards and battery holder.

13. Flat clamp part for rigidly fastening the battery in the cavity of the handle.

14. The controller board for controlling a multifunctional device contains a gyroscope and an accelerometer for determining the orientation in space of a surgical instrument and a data transmission device via a wireless interface.

15. Racks for mounting control boards, providing rigid fastening of the main electronic components to the end surface of the handle inside the body of the multifunctional device.

16. Board for converting the signal from a six-axis force and torque sensor into a digital signal for further transmission to the controller of a multifunctional device.

17. Housing part used to protect the electronic components of the device from the external environment.

18. Nuts that provide rigid fastening of the body to the handle.

19. A cylindrical part that holds the battery in the cavity of the handle.

20. Racks for attaching the signal conversion board to the control board.

21. Connectors for connecting the data conversion board from a six-axis force and torque sensor to the controller of a multifunctional device.

22. Screws for fastening the data conversion board from the six-axis force and moment sensor to the mounting posts.

23. Screws that provide rigid fastening of the housing to the handle.

24. Screws that provide rigid fastening of the external control board to the housing.

25. External control board having a control button in the form of an electromechanical lever switch and an LED.

26. Nuts that secure the external control board to the housing.

27. Screws that provide rigid fastening of the housing to the six-axis force and moment sensor.

28. Flange for attaching to a six-axis force and moment sensor, which ensures rigid installation of the necessary parts and surgical ones.

29. Screws that provide rigid mounting of the flange to the six-axis force and moment sensor of the multifunction device.

30. Clamp for the case, screws onto the flange and secures the case to the device.

31. Flange Mount Button, used to more rigidly mount a surgical instrument into a flange, which is attached to a six-axis force and moment transducer and allows for quick changes of surgical instruments during neurosurgical surgery.

32. Surgical instrument change button, which allows you to install interchangeable surgical instruments.

33. Removable mount for surgical instrument, allowing quick change of surgical instrument during neurosurgical operation.

34. A pin is installed in a groove in the removable mount part, and limits the relative linear movement of the buttons.

35. Springs are used to ensure the operation of buttons in a removable mount.

36. Replaceable surgical instrument - a tap for threading with a cylindrical mount.

37. Replaceable surgical instrument - an awl with a cylindrical mount.

38. Replaceable surgical instrument for tightening pedicle screws with cylindrical fastening.

39. Replaceable surgical instrument for tightening transpedicular nuts with cylindrical fastening.

40. Replaceable surgical instrument for correcting the position of the transpedicular rod with a cylindrical fastening.

41. Replaceable surgical instrument probe, curved to create a channel in the patient's soft tissue with a cylindrical attachment.

42. Replaceable surgical instrument, straight probe for creating a channel in the patient’s soft tissue with a cylindrical mount.

43. A sharp interchangeable surgical instrument for creating a channel in the patient’s soft tissue with a cylindrical mount.

44. Screw-implant used in transpedicular fixation of the human spine.

45. Multifunctional wireless device with replaceable surgical instruments for measuring their orientation in space and the forces and moments acting on them during neurosurgical operations.

46. Multifunctional wireless device control unit.

47. Personal computer used for recording and processing data.

48. Multifunction wireless device software.

49. Part of the HMI user interface used to output data from sensors.

50. Part of the human-machine interface user interface used to control the flow of data from a device.

Carrying out the invention

A multifunctional wireless device with replaceable surgical instruments for measuring their orientation angles in space and the forces and moments acting on them during neurosurgical operations is an invention made in metal (stainless medical steel) and in plastic, allowing measurements to be taken during surgical procedures in neurosurgery.

A multifunctional wireless device for measuring forces and moments acting on surgical instruments and determining the orientation angles of this surgical instrument during neurosurgical operations is shown in Figure 1, 2 and 3; it consists of a handle 11, which has an internal cavity for a battery 7, which powers all electronic multifunction device components, and

wire interface connector 3 for connecting a charger, the immobility of the connector in the handle is ensured by a nut 5, which secures it to the sleeve 4 and is subsequently clamped with a nut with an external thread 2. Protection from the external environment on the battery 7 is provided by a screw cap 1, immobility is ensured by a spring 6. A cylindrical body 17 is rigidly attached to the handle by means of screws 23 and nuts 18, the battery 7 is installed inside the hollow handle through the upper hole and clamped by parts 19 and 13, then a controller 14 is installed on the racks 20, containing a six-axis inertial orientation sensor (accelerometer and gyroscope) and a wireless data transmission module, then a signal processing module from a six-axis force and torque sensor 16 is installed on the racks 15 and connectors 21. Also installed inside the case is a flexible flat antenna and an external control board with a control button in the form of a lever switch and an LED 25, screwed to the housing with screws 24 and nuts 26. On the upper end surface of the housing 17, by means of screws 27, a six-axis force and torque sensor 10 is installed, connected via a wire connector 9 to the signal conversion module 16, which in turn, through two connectors for combining boards 21, transmits data to the controller 14. The main flange 28 is installed to the six-axis force and torque sensor 10 using screws 29, onto which an additional removable mount for the surgical instrument 33 is sequentially screwed by pressing button 31, and by pressing button 32 , replaceable surgical instrument: tap for threading 36, awl 37, screwdriver for tightening pedicle screws 38, screwdriver for tightening pedicle nuts 39, transpedicular fork 40, curved transpedicular probe 41, straight transpedicular probe 42 and straight sharp probe 43. Such fastening will allow the surgeon to quickly and without additional sterilization change the surgical instrument during a neurosurgical operation. A clamp for a surgical insulating sheath 30 is screwed onto the main flange 28. Data on the orientation in space, forces and moments acting on the surgical instrument are sent to the controller 14, which in turn generates a data packet and sends it to a remote server in the control unit 46 via a wireless interface , where they are recorded in a buffer and transmitted via another wireless interface to a personal computer, where through a human-machine interface they are displayed in a user-friendly form, and further work with data, recording in a log file, mathematical processing and visualization of data is also possible.

The remote server, in the control unit 46, for transferring data between the multifunction device and the user, has the ability to connect multiple devices and multiple users.

The software operation algorithm executed by the controller installed in the multifunctional wireless device is presented in Figure 6. After power is applied, the controller initializes the internal interfaces to receive data from the six-axis inertial orientation sensor and the six-axis force and moment sensor, then connects to the server via the wireless interface , if successful, begins transmitting data in an endless loop at a given frequency; when disconnected from the server, it reconnects.

The software operation algorithm executed by the control system controller is presented in Figure 7. After power is applied, the controller initializes the server and waits for clients to connect. The server is designed for any number of devices, both sending and receiving data. When a new autonomous device is connected, data is written to the buffer; when a new client is connected, data transfer from all autonomous devices begins. At all stages of the server's operation, errors are checked, and if they are present, they are processed and logged.

The operating algorithm of the human-machine interface software is presented in Figure 8. At the first stage, the application's graphical interface is initialized. Next, an attempt is made to connect to the control system server as a receiving client; if the result is positive, data is received, subsequently output to the graphical window of the program, and, if necessary, written to a file. If the connection to the server is negative, a check for errors occurs. Then either the error is processed or the server is reconnected. The user interface of the software is presented in Figure 9 and consists of two semantic parts: a field for outputting data from sensors with 3D visualization of the device orientation 48 and a control panel, with buttons for connecting, recording and converting data files 49.

The data processing algorithm is presented in Figure 10. Processing data on the angle of rotation of an improved multifunctional device consists of a step-by-step transformation of the data into a visual and convenient form, which will allow, based on these data, to obtain the most accurate estimate of the linear movement of the device. Processing of device orientation data is carried out in stages and includes the following points:

1. Determination of the increment of the rotation angle relative to the Z axis in degrees.

First of all, it is necessary to convert the rotation quaternion received from the device into the rotation angle relative to the Z axis in the form of the Euler angle:

where x, y, z, w are the rotation quaternion components received from the device. Let's convert radians to degrees in the angle of rotation of the device relative to the Z axis:

For ease of calculations, let’s convert the device rotation angle values from the interval (-180; 180) to the interval (0; 360):

To correctly determine the increment of the angle of rotation in a cycle, it is necessary to determine and correct the values of the angle of rotation during the transition from 360 to 0 and from 0 to 360. To do this, at each moment of time it is determined whether the value of the angle of rotation is included in a certain interval (for example, (270:90 ), (310:60), etc.), in which the transition is most likely and the increment value is recalculated:

where zcurr is the rotation angle value received from the device at the current point in time, degrees; zprev - rotation angle value received from the device at the previous time point, degrees.

2. Determination of the linear movement of the device along the Z axis.

The discrete value (discr) for determining the magnitude of linear movement from angular movement is determined from the condition of axial movement of the screw by the pitch value per revolution [11]:

discr=Pscrew/360°

Based on filtered data about the increment in the angle of rotation of the device relative to the Z axis (). The total linear movement of the device relative to the Z (L) axis is expressed from the total angular movement of the device:

Lsum=ϕsum⋅discr

To determine the current direction of movement at each step of the algorithm, we find the difference between the current and previous path values:

Next, you should get rid of periodic sharp drops in the value of the torque acting on the surgical instrument, because The angle of rotation, and therefore the torque, is limited during manual surgical manipulation:

3. Filtering the torque value along the Z axis.

To filter the moment, we take into account only those moment points that are measured when the first condition of the previous formula is met. Next, we record the values of linear displacement and torque acting on the surgical instrument, subject to the following conditions:

To determine the current direction of change in torque, at each step of the algorithm we find the difference between the current and previous torque values:

Next, the final filtering of the values of the torque acting on the surgical instrument occurs according to the following condition:

Based on the array of filtered torque data, a center line is constructed. For a better assessment of the process of surgical manipulation, we determine the values of local maximums and minimums of torque according to the following condition:

To quantify the trend of changes in torque during surgical manipulation, average lines are also constructed based on the values of local maxima and minima.

An example showing the performance of the device are the dependencies obtained when processing experimental data from screwing in screw-implants. In this case, the screws of the implants can be screwed into materials with properties that are within the performance characteristics of the six-axis force and moment sensor and the six-axis inertial orientation sensor used in the present multifunctional device. Thus, the measured limiting values of the force characteristics and moment characteristics are in the values of 500 N and 5 N*m. And the measured limit value of the speed of reading the characteristics of the orientation of a multifunctional device in space does not exceed 100 degrees per second. The dependences of the obtained moments of resistance to rotation of the screw-implant in the materials are illustrated using graphs. The torque processing graph and the resulting graph of torque versus surgical instrument movement are presented in Figure 11(a). The final graph of torque versus displacement is presented in Figure 11(b).

Additionally, the results of dependency processing can be expressed by criteria. To do this, the following key criteria were used, quantitatively describing the process of surgical manipulation to create a thread with a tap or screw an implant screw into the patient’s soft tissue:

1. The value of the linear movement of the surgical instrument along the Z axis (L).

2. The maximum absolute value of the torque acting on the surgical instrument along the Z axis (MZmax).

3. The slope coefficient of the center line of the filtered value of the torque acting on the surgical instrument along the Z axis (K).

4. Centerline offset of the filtered torque value acting on the surgical instrument along the Z axis. (b).

5. Standard deviation of the filtered torque value acting on the surgical instrument along the Z axis relative to the center line. (S).

6. The average value of the torque between the midlines of the minimums and maximums of the torque acting on the surgical instrument along the Z axis. (d).

7. The slope coefficient of the center line based on the local maxima of the filtered value of the torque acting on the surgical instrument along the Z axis (Kmax).

8. Shift of the midline along the local maxima of the filtered value of the torque acting on the surgical instrument along the Z axis (bmax).

9. Standard deviation of local maxima of the filtered value of the torque acting on the surgical instrument along the Z axis, relative to the center line along the local maxima. (Smax).

10. Average value of the torque between the center line and the center line along the local maxima of the torque acting on the surgical instrument along the Z axis (dmax).

11. The slope coefficient of the center line based on local minima of the filtered value of the torque acting on the surgical instrument along the Z axis (Kmin).

12. Shift of the center line along local minima of the filtered value of the torque acting on the surgical instrument along the Z axis (bmin).

13. Standard deviation of local minima of the filtered value of the torque acting on the surgical instrument along the Z axis, relative to the center line along the local minima. (Smin).

14. Average value of the torque between the center line and the center line along the local minima of the torque acting on the surgical instrument along the Z axis (dmin).

Figure 12 is a graph of filtered torque (Z) versus linear displacement (Z) with criteria noted that quantitatively describe the process of performing a surgical procedure.

Claims (1)

A wireless device for measuring orientation angles and determining the forces and moments acting on interchangeable surgical instruments during neurosurgical operations, including a hollow handle for manual operations containing a rechargeable battery to power all electronic parts, a housing inside which a six-axis inertial orientation sensor based on a gyroscope is installed and accelerometer, controller, signal processing module from a six-axis force and moment sensor and an external control board with a control button and LED; a six-axis force and moment sensor is attached to the end part of the case, on which a flange and a threaded removable holder with buttons are installed, allowing quick change of surgical tools during the operation, while the six-axis force and moment sensor and the six-axis orientation sensor are connected to the controller in the housing, which, in turn, is connected via a wireless interface to the device control unit for wireless connection, control and reception of data by the user’s personal computer with the ability to record and displaying data in graphic, sound and light form with visual indication when the maximum specified manipulation parameters are exceeded.