JPH0723976A - Method and device for detecting intramedullary-nail lateral stop hole - Google Patents

Abstract

PURPOSE:To eliminate the risk of exposure by detecting a lateral stop hole according to echo height while scanning an ultrasonic signal in a direction perpendicular to the axis of an intramedullary nail. CONSTITUTION:After an intramedullary nail 3 is inserted into the marrow 7a of the femur 7, the second hollow rod of a target device is arranged on a plane perpendicular to the lateral stop hole 4 of the intramedullary nail 3, and the end of the supporting rod 26 of the target device is attached to an ultrasonic probe 32. An ultrasonic wave is incident between the transducer 40 of the ultrasonic probe 32 and the skin of the muscle 9 of the thigh from above the skin and toward the intramedullary-nail lateral stop hole 4. The intramedullary-nail lateral stop hole 4 can be positioned with precision by measuring the echo height of the ultrasonic wave which is transmitted through the femur 7 and reflected from near the intramedullary-nail lateral stop hole 4 as the ultrasonic probe 32 is moved. The risk of exposure can thus be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting a lateral stop hole of an intramedullary nail, and particularly when, for example, performing a bone joining operation for a fracture, the bone and the intramedullary nail are fixed after inserting the intramedullary nail. And device for detecting an intramedullary nail lateral stop hole for screwing in a screw screw to be used.

[0002]

2. Description of the Related Art As one of osteosynthesis for bone fractures, a method of fixing bone by simply inserting an intramedullary nail into the intramedullary column, and a method for fixing the intramedullary nail lateral locking hole from above the skin There is a method to fix the bone and the intramedullary nail with a screw screw after making a hole in the bone with a drill. In the latter case, a target device 1 (shown by ACE) is used as shown in FIGS. 17 and 18, and X-rays 2 are applied to the lateral stop holes 4 of the intramedullary nail 3 while irradiating X.
The side stop hole is monitored by a line image, or the position of the side stop hole 4 is determined by freehand. Specifically, in the work using the product of ACE Co. of FIG. 18, the position of the guide sheath 6 is set to the femur 7 (see FIG.
A system is adopted in which the guide sheath 6 can be slid in a direction perpendicular to the axis of 7) and the guide sheath 6 can be fixed with a screw 8 (8 ').

According to the target device 1 as described above, exposure can be reduced and the screw screw to the intramedullary nail lateral stop hole can be reduced as compared with the case where the position of the lateral stop hole is determined by freehand under fluoroscopy as before. It can be fixed more easily.

[0004]

However, the use of the target device 1 is less exposed to radiation than the work of determining the position of the lateral stop hole by freehand under radiography, but its success rate is low. This is because the position of the guide sheath 6 at the distal end portion of the target device 1 is slightly deviated from the lateral stop hole 4 after the intramedullary nail 3 is inserted into the intramedullary space. It is considered that the cause of this deviation is that the intramedullary nail 3 is bent due to the curved femur 7. It should be noted that the expansion and contraction and twist of the intramedullary nail 3 can be ignored. In addition to the X-ray exposure to the patient now and in the future, the exposure to the hands of doctors who operate a number of times is a serious health problem. That is, the work of detecting the intramedullary nail lateral stop hole position on the skin irradiates X-rays for several minutes to determine one hole position (usually there are two places), so that not only the patient but also the doctor The radiation exposure is very high. Therefore, there is a demand for a surgical method that is free from the fear of being exposed to radiation.

Therefore, a main object of the present invention is to provide a method and apparatus for detecting the position of the intramedullary nail lateral stop hole without fear of exposure.

[0006]

According to a first aspect of the present invention, there is provided a method of detecting a lateral stop hole of an intramedullary nail inserted into an intramedullary nail while scanning an ultrasonic signal in a direction orthogonal to an axis of the intramedullary nail. A lateral stop hole detecting method is characterized in that the lateral stop hole is detected based on the height of an echo. A second invention is a device for detecting a lateral stop hole of an intramedullary nail inserted into an intramedullary, wherein an ultrasonic probe and an ultrasonic signal from the ultrasonic probe are transmitted to an axis of the intramedullary nail. A lateral stop hole detecting device is provided with scanning means for scanning in a direction orthogonal to each other, and detects the lateral stop hole based on an echo obtained from an ultrasonic probe.

[0007]

[Operation] Ultrasound propagates through muscles, bones and bone marrow.
Moreover, since the bone marrow and the intramedullary nail, which is generally made of metal, have large differences in acoustic impedance, ultrasonic waves are sufficiently reflected at the intramedullary nail portion, and the echo received by the ultrasonic probe is clear. can get. Therefore, the intramedullary nail hole position can be determined very accurately.

[0008]

According to the present invention, since the position of the intramedullary nail hole is grasped by the echo of the ultrasonic signal, there is no fear of being exposed to radiation as compared with the conventional one using the X-ray, and the position can be determined. I can grasp it accurately. Therefore, the screw screw for fixing the bone to the intramedullary nail inserted in the bone can be attached at an accurate position, and therefore, the operation can be performed more accurately and the time can be saved.

The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.

[0010]

In the embodiment according to the present invention, the target device 10 shown in FIGS. 1 to 3 is used as in the conventional case. The target device 10 includes a support rod 12 fixed to the intramedullary nail 3 (FIG. 17), and an upper end of the support rod 12 has a first hollow rod 14 having a rectangular cross section, for example.
Is fixed. The second hollow rod 16 is slidably inserted into the first hollow rod 14, and the second hollow rod 16 is expanded and contracted in the first hollow rod 14 as shown by an arrow A in FIG. The position of the second hollow rod 16 with respect to the first hollow rod 14, that is, the expansion / contraction position, is fixed by a screw 18 that penetrates the side face of the first hollow rod 14 and has its tip abutting the side face of the second hollow rod 16. .

In the vicinity of the tip of the second hollow rod 16, especially in FIG.
As can be seen from FIG. 3 and FIG. 3, a slider 22 is built in, a through hole 24 is formed in this slider 22, a cylindrical guide rod 25 is inserted into this through hole 24, and this guide rod 25 is It is fixed by the set screw 27. However, the set screw 27 is rotated by a driver or the like inserted through the hole 28 on the side surface of the second hollow rod 16. Then, the support rod 26 is inserted into the guide rod 25,
The support rod 26 is fixed to the guide rod 25 by a set screw 29. The upper and lower ends of the support rod 26 are attached to the second hollow rod 16
The second hollow rod 16 is vertically projected through the elongated holes 30 formed in the upper and lower surfaces in the same manner. The ultrasonic probe 32 is fixed to the lower end of the support rod 26. More specifically, as shown in FIG. 3, the case 34 of the ultrasonic probe 32 is
The upper surface convex portion 36 of the concave portion 3 formed at the lower end of the support rod 26.
8 and both are fixed by a set screw 39,
As a result, the case 34 is detachably attached to the support rod 26. In this case 32, the ultrasonic transmitter / receiver 4
0 is attached. Therefore, when the slider 22 is moved in the arrow B or C direction in FIG. 3 by the screw 42, the ultrasonic probe 32 is also moved in the same direction accordingly.

A screw 42 for moving the slider 22 in the arrow AB or C direction is inserted into the second hollow rod 16 through a screw hole 44 formed in the side surface of the second hollow rod 16. The tip of the screw 42 is rotatably fixed to the recess 46 of the slider 22. That is, this recess 46
A bearing 48 capable of holding an axial load is attached to the bearing 48, and an outer ring of the bearing 48 is fixed with a set screw 50. Then, the tip of the screw 42 is exposed in the recess 46, and the tip is fixed to the inner ring of the bearing 48 by the nut 52, for example. Therefore, when the screw 42 is turned, its tip is displaced in the direction of arrow B or C, the inner ring of the bearing 48 is rotated accordingly, and the slider 22 is displaced. In this way, by rotating the screw 42, the ultrasonic probe 32 can be moved in the arrow B or C direction and positioned. The second hollow rod 16 is shown in FIG.
Since it extends in the axial direction of the femur 7 shown in FIG. 7, the ultrasonic probe 32 is consequently moved or displaced in the axial direction of the femur 7, that is, the intramedullary nail 3.

A position detector 54 shown in FIG. 4 is connected to the screw 42. The position detector 54 is, for example,
A pulse signal is generated according to the rotation of the screw 42, and the pulse signal is measured to output data indicating the position of the screw 42, that is, the position of the ultrasonic probe 32. The position detector 54 is connected to the detection circuit 56 together with the ultrasonic wave transmitter / receiver 40 included in the ultrasonic probe 32.

More specifically, the ultrasonic transmitter / receiver 40 includes:
Transmission pulse driver 6 based on the signal from the oscillator 58
A transmission pulse output from 0 is given. That is,
The oscillator 58 is configured as, for example, a crystal oscillator, and generates a pulse signal having a repeating cycle that reaches the vibration frequency of the ultrasonic wave transmitter / receiver 40, and the pulse signal is given to the transmission pulse driver 60. The wave transmission pulse driver 60 amplifies the pulse signal to generate a wave transmission pulse voltage, and the wave transmission pulse voltage is applied to the ultrasonic wave transceiver 40. The ultrasonic wave transmitter / receiver 40 generates an ultrasonic wave pulse in response to the transmission pulse voltage, and the ultrasonic wave pulse is applied to the femur 7 or the intramedullary nail 3 as described above.

On the other hand, the reflected pulse (echo) generated by the irradiation of the ultrasonic wave pulse is converted into an electric signal by the ultrasonic wave transmitter / receiver 40. The echo signal is amplified by the reflection pulse receiver 62 and then detected by the detection circuit 64. The echo detected by the detection circuit 64 is waveform-shaped by the waveform shaping circuit 66, and then converted into digital data indicating the echo height by the AD converter 68. This echo height data is stored in the RAM of the storage device 70.
Further, the echo signal whose waveform has been shaped by the waveform shaping circuit 66 is input to the CRT display 72, and its waveform is CR.
Displayed on T. The CRT display 72 is controlled by a CRT controller 74 like an oscilloscope. That is, the position data from the position detector 54 described above is input to the CRT controller 74 via the bus 76, so that the horizontal axis of the CRT display 72 is defined by the position data.

Further, the CRT controller 74 and the storage device 70 are connected to the CPU 78 via the bus 76 and controlled by the CPU 78. Then, the position data and the echo height data stored in the storage device 70 are appropriately processed by the CPU 78 and stored again in the storage device 70. In addition, the data processed in this manner may be stored in the external memory 80 such as a magnetic tape, a hard disk, or a magneto-optical disk, if necessary.
Recorded in.

Next, referring to FIGS. 5 and 6 and FIGS. 7 and 8, using such a target device 10, an ultrasonic probe 32 and a detection circuit 56 are used to laterally stop the intramedullary nail. A method of detecting a hole will be described. After inserting the intramedullary nail 3 into the marrow 7a of the femur 7, as shown in FIG. 5, the second hollow rod 16 of the target device 10 is placed on a plane perpendicular to the lateral stop hole 4 of the intramedullary nail 3. Then, the ultrasonic probe 32 is attached to the tip of the support rod 26 of the target device 10. Then, between the transducer 40 of the ultrasonic probe 32 and the skin of the thigh muscle 9, for example, an acoustic coupling agent such as sonojelly (trade name: Toshiba Medical Co., Ltd.) is interposed, and the intramedullary nail is laterally fixed from above the skin. An ultrasonic wave is incident toward the hole 4 direction. The ultrasonic probe 32 is on a plane perpendicular to the intramedullary nail lateral stop hole, and on that surface, as described above, the direction (Z direction) perpendicular to the axis of the femur 7 is set by the screw 42.
(Axial direction), that is, in the direction of arrow B or C. At this time, in response to the displacement or movement of the ultrasonic probe 32, the echo height at which the ultrasonic wave passes through the femur and is reflected from the portion near the intramedullary nail lateral stop hole 4 is displayed on the CRT display 72. The position of the lateral stop hole 4 can be determined by measuring the position of the lateral stop hole 4. The method of detecting the intramedullary nail lateral stop hole varies depending on the state of incidence of the ultrasonic beam from the ultrasonic probe 32.

FIG. 5 and FIG. 6 show a shape in which the intramedullary nail 3 has a circular or curved cross section with a lateral stop hole 4 through which a screw screw passes, and the ultrasonic probe 32 has a transducer or a transmitter / receiver. This is the case where the size d1 of the wave device 40 is larger than the diameter d2 of the lateral stop hole 4. In this case, when the ultrasonic probe 32 is moved by the screw 42 in the Z-axis direction perpendicular to the axis of the femur 7, that is, the arrow B or C direction, the echo height is initially zero, but Z = It increases as it approaches the position of 0, reaches its maximum at Z = 0, and then decreases to zero. In this way, when the ultrasonic probe 32 is scanned or moved by the screw 42, the position of Z = 0 where the echo height is maximum becomes the center of the lateral stop hole 4.

7 and 8 show that the intramedullary nail 3 has a circular or curved cross section, and has a lateral stop hole 4 through which a screw screw passes, and the ultrasonic transducer 32 transmits and receives waves. If the size d1 of the device 40 is smaller than the diameter d2 of the lateral stop hole 4, or if the size of the transducer 40 is larger than the lateral stop hole, the ultrasonic beam is focused, and the ultrasonic beam is positioned near the lateral stop hole. The size d1 'when reaching the side stop hole 4
A case where the diameter is smaller than the diameter d2 is shown. in this case,
When the ultrasonic probe 32 is moved in the direction perpendicular to the axis of the femur 7 by the screw 42, that is, in the Z-axis direction, the echo height is initially zero, but increases as the position approaches Z = 0. However, the echo height becomes smaller as Z = 0 becomes closer, and the echo height disappears when the size of the ultrasonic beam reaches a position inside the lateral stop hole 4. After that, when the ultrasonic probe 32 is further moved in the Z-axis direction,
After the echo begins to occur, it will be lost again. In this way, the center of the position where the echo height disappears, that is, Z =
The position of 0 is the center of the lateral stop hole 4.

As shown in FIG. 9, in the case where the intramedullary nail 3 has a flat cross-sectional shape in the peripheral portion of the lateral stop hole 4, and the lateral stop hole 4 through which the screw screw passes is open,
The size of the transducer 40 of the ultrasonic probe 32 is the lateral stop hole 4
Or the size of the transducer 40 is larger than the lateral stop hole, the ultrasonic beam is focused and the size when the ultrasonic beam reaches the vicinity of the lateral stop hole 4 is smaller than the lateral stop hole. When it becomes smaller, the state of the echo height shows almost the same tendency as that shown in FIGS. 7 and 8 described above, but in this case, since the peripheral portion of the lateral stop hole 4 is a flat surface, it is incident on the flat surface. Since the echo height of the generated ultrasonic wave appears larger than that of the curved surface, not only the measurement is easy but also the measurement accuracy of the lateral stop hole position is improved.

The inventors of the present invention verified the practicality of the above-mentioned embodiment by the following experiments. In the experiment, as shown in FIG. 10, a bone fragment obtained by cutting a pig femur into slices of about 30 mm in length was prepared, and a rubber plate having a thickness of 10 mm was adhered to one side of the bone fragment with an adhesive. 12mm diameter in the center of the plate, 5mm diameter
The intramedullary nail 3 with the lateral stop hole 4 was inserted. This sample was immersed in water at 38 ° C. Then, the transducer surface (diameter 6.4 mm) of the ultrasonic probe is attached to the water surface, the sample is set so that the distance from the transducer surface to the intramedullary nail is 40 mm, and ultrasonic waves are applied. It is incident on the sample. Then, while moving the ultrasonic probe in the Z-axis direction by 1 mm, the diameter 5
The height of the echo obtained from the part near the lateral hole of the intramedullary nail of mm was measured. In this experiment, as an example, Z = 2 mm
An echo as shown in FIG. 11 was observed at the position. In FIG. 11, is an echo from the outside of the femur,
Is an echo from the inside of the femur, and is an echo from the vicinity of the intramedullary nail lateral stop hole 4. Therefore,
The side stop hole can be detected by observing the height of the echo shown here.

In the experiment shown in FIG. 10, the above-mentioned d1>
In the case of d2, as shown in FIG.
The echo shown in is obtained. That is, the position of Z = 0 mm corresponds to the highest position (top) of the cylindrical portion of the intramedullary nail. Therefore, it can be seen from FIG. 12 that the echo height is maximum at the uppermost position of the cylindrical portion of the intramedullary nail. That is, the position where the echo height is maximum is the center position of the intramedullary nail lateral stop hole.

In the experiment shown in FIG. 10, the above-mentioned d1
When (or d1 ′) <d2, the echo shown in FIG. 13 is obtained from the portion near the intramedullary nail lateral stop hole 4. That is, in this case, the echo height becomes almost zero at the position of the lateral stop hole 4. Therefore, the position where the echo height is zero between the portions where the echo height is maximum is the position of the intramedullary nail lateral stop hole 4.

After this position can be determined by the ultrasonic waves in this way, the support rod 2 at the tip of the target device 10 is
Remove the ultrasonic probe 32 attached to 6,
From that position, aim at the femoral bone and intramedullary nail lateral stop hole, and drill a hole in the bone from above the skin. Then, the femur and the intramedullary nail are fixed with a screw. It can be seen that the position of the lateral stop hole can be accurately measured and the intramedullary nail can be laterally stopped by performing such an operation method.

In place of the above-described embodiment, the ultrasonic probe 32 is supported by the support rod 26 as shown in FIGS.
It may be attached to. That is, the cylindrical body 82 is further attached to the guide rod 25 through which the slider 22 in the second hollow rod 16 is inserted, and the cylindrical body 82 is fixed to the guide rod 25 with the set screw 84. Although the screw may be directly attached to the guide rod 25, in this case, since the screw screw is inserted inside the guide rod 25, there is a possibility that an inconvenient problem may occur due to "cutting dust" at the tip of the screw. In order to avoid this, in this embodiment, the cylindrical body 82
It is fixed to the guide rod 25 with a setscrew 84.

A screw hole 86 is further formed in the cylindrical body 82, and a long hole 90 is formed in a half-cylindrical plate 88 extending upward from the case 34 of the ultrasonic probe 32. A set screw 92 is screwed into the screw hole 86 from the outside of the plate 88 through the elongated hole 90, so that the plate 88, that is, the case 34 (ultrasonic probe 32) is moved to the cylindrical body 82, that is, the guide rod 25 (support rod 26). It can be detachably fixed to the. However, the position of the ultrasonic probe 32 in the vertical direction can be adjusted by the elongated hole 90.
The plate 88, that is, the ultrasonic probe 32 can be removed by removing the set screw 92.

[Brief description of drawings]

FIG. 1 is a side view showing a target device used in an embodiment of the present invention.

FIG. 2 is a plan view showing a tip portion of a target device in an enlarged manner.

FIG. 3 is an illustrative view showing a tip portion of a target device in detail.

FIG. 4 is a block diagram showing an example of a detection circuit for detecting an intramedullary nail lateral stop hole by an ultrasonic signal obtained from a target device.

FIG. 5 is an illustrative view showing one example in which an ultrasonic signal is scanned by using the target device shown in FIGS. 1 to 3 to detect a lateral stop hole position.

6 is an illustrative view showing the relationship between the size d1 of the ultrasonic wave transmitter / receiver and the diameter d2 of the lateral stop hole in the case of FIG. 5. FIG.

FIG. 7 is an illustrative view showing another example of the case where the target device shown in FIGS. 1 to 3 is used to scan an ultrasonic signal to detect a lateral stop hole position.

8 is an illustrative view showing the relationship between the size d1 of the ultrasonic wave transmitter / receiver and the diameter d2 of the lateral stop hole in the case of FIG. 7. FIG.

FIG. 9 is an illustrative view showing another example of the intramedullary nail.

FIG. 10 is an illustrative view showing an example of an experiment conducted by the inventors.

FIG. 11 is an illustrative view showing an echo waveform at a position of Z = 2 mm in the experiment of the graphical illustration 10;

12 is a graph showing the Z-axis position and the echo height when d1> d2 in the experimental example shown in FIG.

13 is a graph showing the Z-axis position and the echo height when d1 <d2 in the experimental example shown in FIG.

FIG. 14 is an illustrative view showing another example of the mounting structure of the ultrasonic probe to the target device.

FIG. 15 is a plan view showing a plate in the embodiment of FIG.

FIG. 16 is a side view solution diagram showing a plate in the example in FIG. 14;

FIG. 17 is an illustrative view showing one example of a conventional target device.

FIG. 18 is an illustrative view showing an enlarged tip portion of the conventional target device of FIG. 17.

[Explanation of symbols]

 3 ... Intramedullary nail 4 ... Horizontal stop hole 7 ... Femur 10 ... Target device 14 ... First hollow rod 16 ... Second hollow rod 22 ... Slider 26 ... Support rod 32 ... Ultrasonic probe 40 ... Ultrasonic wave transmission / reception 42 ... Screw 48 ... Thrust bearing 54 ... Position detector 56 ... Detection circuit

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[Procedure amendment]

[Submission date] August 17, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 11

[Correction method] Change

[Correction content]

FIG. 11

Claims (2)

[Claims] 1. A method for detecting a lateral stop hole of an intramedullary nail inserted into the intramedullary nail, wherein the ultrasonic wave signal is scanned in a direction orthogonal to an axis of the intramedullary nail based on the height of an echo. A method for detecting a lateral stop hole, characterized in that the lateral stop hole is detected. 2. An apparatus for detecting a lateral stop hole of an intramedullary nail inserted into an intramedullary, comprising: an ultrasonic probe; and an ultrasonic signal from the ultrasonic probe, A lateral stop hole detecting device, comprising a scanning means for scanning in a direction orthogonal to an axis, the lateral stop hole being detected based on an echo obtained from the ultrasonic probe.