WO2020234506A1 - Method and system for positioning surgical tools for bone surgery - Google Patents

Abstract

The invention relates to a system for assisting in the surgical positioning of wires and pins in bone surgery comprising: a C-arm X-ray machine (1), which is provided with a screen (5); means for transferring images from the C-arm by means of a cable or a camera (2) focused on the screen which captures the image to be sent to a computer (3); a motor (4) provided with a wire orientation detection unit (6), processing means and storage means for a program for analysing and displaying a visual aid which is capable of detecting whether there is a line on an image and, if such is detected, extending the line in order to know where it leads; and wherein the orientation detection unit (6) wirelessly transmits the position and orientation of the wire mounted on the motor (4). This allows precise and rapid positioning with only a few X-ray images of wires on bones before their final insertion.

Description

DESCRIPTION

SURGICAL TOOLS POSITIONING METHOD AND SYSTEM

FOR BONE SURGERY

OBJECT OF THE INVENTION

The object of the present invention is a system to aid in the surgical positioning of surgical tools for bone surgery, such as needles and pins, cup burs, pedicle screws, mechanized saw blades, etc., when they are mounted on surgical instruments. .

Therefore, the present invention is circumscribed within the scope of the apparatus and systems used in navigated surgery.

BACKGROUND OF THE INVENTION

In orthopedic surgery and traumatology, as well as in other surgical specialties (neurosurgery, maxillofacial, etc ...), during surgical acts the need to position needles or pins in the bone is frequent. These needles or pins are intended to directly fix two bone fragments to each other (osteosynthesis), serve as a guide or reference for the positioning of other osteosynthesis devices (plates, cannulated screws, nails, etc ...), or serve as a guide for the performance of osteotomies (cuts in the bone in a certain location and orientation).

The application of the needles or pins is done under direct vision and sometimes by palpation. To calculate the correct trajectory of the needle or pin, as well as to confirm the correct positioning and trajectory of the same, the surgeon usually uses X-ray machines during surgery (fluoroscope or C-arm).

The trajectory and position of the needle must be precisely established in a three-dimensional plane, so X-ray visualization of the anatomical area in at least two planes is necessary (radiographic projections), which is why X-ray images are obtained in at least two positions. In tubular bone and vertebral column, the projections more used are usually anteroposterior (AP) and lateral (LAT). In other areas, other views may be required, for example, in the hip AP and axial (AX) view.

In deep structures (for example, hip and spine), several attempts are usually necessary to establish the correct direction, which implies obtaining multiple X-ray images. Likewise, the need to obtain images in two different projections implies that In the process of changing the position of the fluoroscope, the surgeon may inadvertently change the orientation of the needle or pin slightly, losing reference and having to repeat the process. Also, when the surgeon establishes the correct orientation in one plane, he must then establish the orientation in another projection. This process cannot be performed on both views simultaneously, since the X-ray machine only shows one plane at a time, which implies the need to perform several X-ray checks.

The current procedure presents a series of factors to take into account, which are:

- Radiation applied to the patient and surgical team.

- Surgical time until correct positioning, variable according to the complexity and skill of the surgeon.

- Positioning precision when handling 2 projections serially and not simultaneously.

- Traumatic effect of the passage of needles through the tissues.

The current process of positioning the needles before proceeding to bone drilling is difficult because:

- Sufficient precision is not always achieved.

- When, for example, it is correctly positioned in an anteroposterior position, it is necessary to change the posture to see the axial or lateral positioning, this supposes a few additional seconds, time in which the established position of the needle in the projection can be altered and therefore lose the reference.

- By altering the angulation in one plane, the angulation in the remaining planes is generally inadvertently altered.

A possible option for a correct positioning of the needle quickly and accurately would be to make a continuous X-ray visualization as video (direct fluoroscopy), instead of static images. This would allow you to see how the needle is positioned live, but it involves a large amount of radiation, only admissible in very specific cases. In any case, the X-ray apparatus only allows one perspective to be displayed at a time, so that only one profile is controlled.

Another option is the use of navigated surgery devices, which consist of a series of sensors that are applied to the surgical instruments and allow the virtual position and orientation of the instrument to be visualized. However, these devices have a high cost and require imaging tests (tomography, magnetic resonance) prior to surgery, so they are usually used in more complex or specific procedures.

Therefore, it is the object of the present invention to overcome the drawbacks noted in the correct positioning of the needle or pin before proceeding with a bone perforation, particularly a possible lack of precision, the need to carry out multiple exposures to X-rays, intervention time and high cost, developing a system such as the one described below and is reflected in its essentiality in the first claim.

DESCRIPTION OF THE INVENTION

The object of the present invention is a method and a system to aid in the positioning of bone surgery tools, such as surgical needles and pins, coupled to a surgical instrument (also called a motor).

The system of the invention comprises an X-ray apparatus, for taking radiographs, which is preferably of the portable type, such as C-arm or fluoroscopes. The X-ray machine may be provided with a screen on which the radiographs made by the X-ray machine are displayed.

Also included in the system of the invention is an orientation detection unit mounted on surgical instruments intended to carry the bone surgery tool, such as the aforementioned surgical needle or pin, where the orientation detection unit comprises a inertial measurement unit, to determine the positioning and orientation of surgical instruments, and wireless transmission means to send data on the positioning and orientation of the bone surgery tool mounted on the surgical instruments.

Finally, the system comprises a processor to process and store a visual aid analysis and representation program that on an image is capable of detecting if there is a line and in case of detecting it, prolonging the line in order to indicate its trajectory, as explained later.

According to a less preferred but less technologically demanding embodiment, the system may include a camera (for example, a webcam) focused on the screen of the X-ray apparatus, and that captures the image displayed by the screen, to be sent to a computer on whose monitor is shown said image corresponding to the radiography taken.

Alternatively, more preferably, the processor could be integrated into the X-ray apparatus itself, together with a wireless module, which would make it possible to dispense with both the camera and the computer.

On the other hand, as an even more preferred alternative embodiment, the system comprises a means for exporting the images from an image output port of the X-ray apparatus to the computer, for said images to be processed by the computer program, through a connection by cable, for example, HDMI, between the two, without the need for a camera.

Thanks to the system described and the processing means when an osteosynthesis material has to be implanted on a bone (in the present case, needle or pin), an X-ray is first performed according to a certain projection, for example anteroposterior, showing the needle or pin mounted on surgical instruments that have been previously positioned in the most suitable direction. The X-ray apparatus is then moved, without moving the surgical instruments with the needle or pin, and a second X-ray is taken in a second projection, for example axial, in which the needle has been previously positioned again. engine in the most suitable position. The surgical material is radiopaque, so its outline is seen on the radiograph as a line. The aforementioned analysis program is capable, from the lines corresponding to the contour of the surgical material shown in the radiographs, to continue the straight line making a long line that shows the estimated trajectory.

For better operation of the invention, the changing position of the surgical instruments maintains a fixed point, preferably at the tip of the needle or pin, which can, for example, be supported on the same point of the bone that is destined to be operated on, or another point of the patient close to said bone.

Once the estimated trajectories are represented in the projections made, for example anteroposterior and axial, the program also represents lines on the screen superimposed on the radiographic image that correspond to the trajectories in real time according to the movements of the surgical instruments , and which are obtained from the orientation detection unit.

In accordance with the foregoing, the present invention makes it possible to accurately determine, with only two radiographs, the trajectory and position of the needle or the pin before performing the perforation, where in addition a shorter surgical time and fewer necessary radiographs are convenient. to correctly position a needle, and where the final cost is much lower than conventional 3D navigation systems (navigated surgery).

The program numerically represents the angulation in the three planes of space (X, Y, Z axes, or yaw, pitch, and roll) of the instrument to which the orientation detection unit is attached. In addition, it allows to store specific positions, representing numerically the difference in degrees of the variation of the posture with respect to the stored position.

To avoid distortion effects in the representation of the angle in oblique projections, the program has a calibration function that memorizes the orientation of the X-ray apparatus, and performs the correction calculations based on said orientation.

Other uses of the invention are derived from applying the inertial measurement unit to another type of surgical instrument, and thus benefit from obtaining real-time data on its orientation in space with respect to the patient. For example for the orientation of cup burs in prosthetic hip surgery, insertion of pedicle screws in vertebral surgery, and orientation of the mechanized saw blade to perform corrective osteotomies of uni or biplanar angulation, being especially useful in the latter case.

Unless otherwise indicated, all technical and scientific elements used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention pertains. Similar or equivalent methods and materials to those described herein can be used in the practice of the present invention.

Throughout the description and the claims the word "comprises" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will emerge partly from the description and partly from the practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of a practical embodiment thereof, a set of drawings is attached as an integral part of said description. where by way of illustration and not limitation, the following has been represented.

In figure 1, we can see the fundamental elements that are part of the system object of the invention.

In figure 2, we can see in detail the drill or drilling motor, with the orientation detection unit attached to it.

Figure 3 shows the elements that are part of the Inertial Detection Unit

Figure 4 shows a representation of a possible screen that would be displayed on the computer used in the system. DESCRIPTION OF A PREFERRED EMBODIMENT

In view of the figures, a preferred embodiment of the proposed invention is described below.

In figure 1 we can see that the system for the correct positioning of needles and pins for bone surgery comprises:

- An X-ray machine (1) of the “C” -bow type, also called fluoroscope, provided with a screen (5) in which the static images of the radiographs taken are shown.

- A camera (2) oriented to the screen (5) of the X-ray apparatus.

- A computer (3) that is connected to the camera (2) and that displays the images of the radiographs and transmitted by the camera (2) and is provided with a processor to process and store a computerized vision program that over an image it is capable of detecting if there is a line and in case of detecting it extend the line in order to know its trajectory.

- A surgical instrument (4) on which an orientation detection unit (6) (figure 2) is attached, which is provided with means to determine the positioning and orientation of the surgical instruments, as well as wireless transmission of the positioning and orientation of the needle or pin mounted on the surgical instruments (4).

According to a preferred example, the processor can be arranged as part of the X-ray apparatus (1), together with a wireless module, with which the camera (2) and the computer (3) could be dispensed with, showing the lines on the screen (5) of the X-ray apparatus (1).

According to another alternative, more preferred example, the computer (3) is used but the camera (2) is dispensed with, so that the X-ray apparatus (1) has an image output port (not shown), which is connectable to the computer (3) via an image cable, eg HDMI. The detection and orientation unit (6) is mounted and coupled on the surgical instruments (4) comprising a casing (6.1) that must meet the following requirements:

- Be watertight, plastic or metal.

- Be sterilizable (via ethylene oxide, or autoclave).

- Allow the insertion of the device in the same maintaining the conditions of sterility by the surgical team.

- Present a temporary anchoring system to the surgical instruments in which the needle or pin are mounted (drill, T-handle, etc ...).

- Allow manipulation of the buttons and display of the LEDs in sterile conditions.

- Adaptable to the specific instrument model used in surgery (motor, T-handle, etc ...).

The detection and orientation unit (6), as seen in figure 3, comprises:

- An IMU (7), that is, an inertial measurement unit, preferably 6 DOF (6 degrees of freedom), which consists of a magnetometer, accelerometers (preferably 3), gyroscopes (preferably 3) and thermometer.

- A processing board (8), together with a Bluetooth and WiFi module.

- LED position indicators, which are a first LED (10) axial positioning indicator, and a second LED (9) Antera Posterior positioning indicator

- Buttons for interface with surgical instruments, specifically a first button (11) and a second button (12)

- A battery (13) to power the detection and orientation unit (6).

- MiniUSB charging port.

The computer vision program hosted on the computer performs the following actions, which are better understood with the help of Figure 4:

- Obtains the images from the screen (5) of the fluoroscope or X-ray device (1) ₇ either through the camera (2), for example, a webcam, if applicable, or directly from the X-ray device (1), or through the image output port of the X-ray apparatus (1), as explained above. - Analyze these images and detect the presence of the outline of a needle or pin in them.

- Once detected, it represents a segment (14) on the needle or pin detected in color, indicating the end end of the needle or pin, and prints on the screen a first line (16), in extension of the segment (14), preferably in color, indicating the estimated trajectory of the needle or pin. This image can be frozen.

- Likewise, the program detects the changes in the position of the needle in real time and draws on the screen the estimated trajectory of the needle based on said changes, by means of a second line (15), preferably in a discontinuous line and of a different color than the first line (16), and representing the real-time trajectory of the needle.

- The program can store radiographic images of two different projections, indicating the trajectory of the needle in real time in both planes of space. To do this, it uses accelerometer, gyroscope (s) and magnetometer data (temperature compensated) transmitted wirelessly by the orientation detection unit.

In figure 4 two different projections are shown, the one on the left of the image is an anther posterior view (AP) where the real-time trajectory, that is, the second line (15) is deviated by about 4 ^o with respect to the trajectory. initially estimated, that is, the first line (16), while in the axial projection, which corresponds to the image on the right, which corresponds to an axial view, we observe that the first line (16) practically coincides with the second line (15).

The software can have a calibration function that allows to establish the orientation of the X-ray apparatus in the axial projection, to avoid distortions of the representation of this angle even if the needle is not perpendicular to the apparatus, aligning the surgical instruments with a collector of the X-ray apparatus and using one or both buttons (1 1, 12), for example, by pressing both buttons (11, 12) at the same time. This stores the position of the X-ray apparatus in the axial projection and performs the distortion and variation calculations of the needle in the Axial plane based on the corresponding viewing angle.

The buttons (11, 12) and the LEDs (9, 10) serve to carry out various functionalities of the invention, as explained below by way of example. If, for example, a shorter press of the buttons is made (less than 1 second, for example) the image on the screen is frozen and the real-time detection of the path variation begins. Pressing again unfreezes the image.

If a longer press is made, for example, between 1 to 5 seconds, a specific orientation is stored, so that, with the position stored, when the surgical instrument is positioned in that stored orientation, an LED lights up. If the position of the surgical instruments is altered in the yaw plane (Y axis), the vertical tilt is calculated. If the current position matches the stored position, an LED of one color, such as green, lights up. In the case of the lateral plane (pitch axis, X axis) the LED is of another color, such as blue.

If a long press is made for example, longer than 5 seconds, the stored angle is cleared and an asterisk (*) appears on the screen.

Both ways of detecting the needle or pin could be combined, both the one carried out by means of the LEDs, and the one carried out by representing the estimated and real trajectories on the computer monitor, which would allow me to see the trajectories in real time and its variations in two simultaneous projections.

Various highlighted preferred embodiments of the invention are mentioned below.

- System for the correct positioning of needles and pins for bone surgery characterized in that it comprises:

- An X-ray machine (1) of the “C” type arc, provided with a screen (5) in which the static images of the radiographs taken are shown.

- A camera (2) oriented to the screen (5) of the X-ray apparatus.

- A computer (3) connected to the camera (2) and that displays the images of the radiographs taken, and transmitted by the camera (2) and is provided with first means of processing and storing a computerized vision program that an image is capable of detecting if there is a line and if it is detected, prolonging the line in order to know where it is going.

- A motor (4), generally a surgical instrument, on which an orientation detection unit (6) is fitted and which is provided with means of processing and storage of a data processing program of the orientation detection unit (6), as well as wireless transmission of the positioning and orientation of a needle mounted on the motor (4).

- The system mentioned in the previous embodiment, where the detection and orientation unit (6) comprises:

- IMU, (inertial measurement unit) (7), preferably 6 DOF (6 degrees of freedom), consisting of a magnetometer, 3 accelerometers, 3 gyroscopes and a thermometer.

- A processing board (8), together with a Bluetooth and WiFi module.

- LED position indicators, which are a first LED (10) axial positioning indicator, and a second LED (9) Antera Posterior positioning indicator

- Buttons for interface with surgical instruments, specifically a first button (1 1) and a second button (12)

- A lithium battery (13) to power the detection and orientation unit (6)

- MiniUSB charging port.

- The system mentioned in either of the two previous embodiments, where the detection and orientation unit (6) is mounted and coupled on the motor (4) comprising a casing (6.1) that must meet the following requirements:

- Be watertight, plastic or metal.

- Be sterilizable (via ethylene oxide, or autoclave).

- Allow the insertion of the device in the same maintaining the conditions of sterility by the surgical team.

- Present a temporary anchoring system to the needle or pin insertion device (drill, T-handle, etc ...).

- Allow manipulation of the buttons and display of the LEDs in sterile conditions.

- Adaptable to the specific instrument model used in surgery (motor, T-handle, etc ...).

- Computerized vision program housed in the computer (3) of the system for the correct positioning of needles and pins for bone surgery, according to any of the previous embodiments, performing the following actions: - Obtains images via webcam from the screen (5) of the fluoroscope or X-ray machine (1).

- Analyze said image and detect the presence of a needle or pin in it.

- Once detected, it represents a segment (14) on the detected needle or pin in color, indicating the end of the needle or pin, and prints a color line on the screen indicating the estimated trajectory (16) of the needle or pin . This image can be frozen.

- Likewise, the program detects the changes in the position of the needle in real time and draws on the screen the estimated trajectory of the needle based on said changes, that is, it draws the trajectory in real time (15) of the needle, where the program can store radiographic images of two different projections, indicating the trajectory of the needle in real time in both planes of space. To do this, it uses accelerometer, gyroscope and magnetometer data (temperature compensated) transmitted wirelessly by the needle or pin orientation detection unit.

Claims

1.- Positioning method of surgical tools for bone surgery, characterized in that it comprises the following stages: - Access at least two X-ray images taken by an X-ray machine (1) in which a surgical tool mounted on a surgical instrument (4) appears in different radiographic projections of the same position; - Analyze the images and detect in said images the presence of the surgical tool; - Represent in the images a first straight line (16) that is collinear with the surgical tool; - Detect changes in position of the surgical tool mounted on the surgical instruments (4); - Represent in the images a second straight line (15) corresponding to the changing position of the surgical tool in real time. 2.- Method according to claim 1, characterized in that it additionally comprises a step of representing in the radiographic images, prior to the first line (15), a segment (14) corresponding to the surgical tool, of which segment (14) the first line (16) is an extension. 3. Method according to any of claims 1-2, characterized in that the change in position of the surgical instruments (4) maintains a fixed point. 4 - Method according to claim 3, characterized in that the fixed point is the end of the surgical tool. 5. Method according to any of claims 1-4, characterized in that the surgical tool is selected from: needle, pin, cup bur, pedicle screw, mechanized saw blade. 6.- Positioning system of a surgical tool for bone surgery, characterized in that it comprises: - an X-ray machine (1), intended to take radiographs; - a surgical instrument (4), intended to carry the surgical tool, and in which is mounted an orientation detection unit (6) configured to detect the position of the surgical instrument (4) and send data on said position wirelessly ; Y - a processor configured to carry out the steps of the method described in claims 1-4. 7. System according to claim 6, characterized in that the X-ray apparatus (1) further comprises a screen (5) intended to display images of the radiographs. 8. System according to any of claims 6-7, characterized in that the processor is integrated in the X-ray apparatus, as well as the X-ray apparatus (1) also incorporates a wireless module to receive the changing position data from the orientation detection unit (6). 9. System according to any of claims 6-7, characterized in that it also comprises a computer, which includes: the processor, and a monitor to display the first line (16) and the second line (15) in the X-ray images . 10. System according to claim 9, characterized in that the computer (3) is connectable to an image output port of the X-ray apparatus (1) through an image cable, to receive the images of the radiographs. 11. System according to claim 9, characterized by further comprising a camera (2) to record the images shown on the screen (5). 12. System according to any of claims 6-11, characterized in that the X-ray device (1) is a portable device of the C-arm type or fluoroscope. 13. System according to any of claims 6-12, characterized in that the detection and orientation unit (6) comprises: - an inertial measurement unit (7), consisting of a magnetometer, accelerometers, gyroscopes and a thermometer; - a processing board (8), together with a Bluetooth and WiFi module .; - LED position indicators (9, 10), which are a first LED (10) indicating a first positioning, for example, axial positioning, and a second LED (9) indicating a second positioning, for example, anterior positioning. later; - buttons (11, 12) for interface with surgical instruments, specifically a first button (11) and a second button (12); - a battery (13), for example lithium, for powering the detection and orientation unit (6); Y - a charging port, for example miniUSB, to recharge the battery (13). 14. System according to claim 13, characterized in that the inertial measurement unit (7) includes three accelerometers and three gyros, to provide six degrees of freedom. 15. Computer program, for computerized vision, characterized in that it contains instructions to carry out the method of claims 1-5. 16. Computer-readable medium, characterized in that it contains the computer program of claim 15 stored.