WO2005011507A1

WO2005011507A1 - A dilator for forming a cavity within the vertebral body

Info

Publication number: WO2005011507A1
Application number: PCT/CN2003/000771
Authority: WO
Inventors: Dewei Zou
Original assignee: Dewei Zou
Priority date: 2003-08-04
Filing date: 2003-09-12
Publication date: 2005-02-10
Also published as: CN1802127A; AU2003264318A1; CN2638760Y; CN100361634C

Abstract

A dilator for forming a cavity within the vertebral body consists of a hollow outer tube (1) and an inner tube (2) inserting into the hollow outer tube (1). The two tubes are fixed at one end and the outer tube (1) is provided with an elastic expandable section (12), the other end of the two tubes is slidingly connected.

Description

Dilator for forming a cavity in a push body

Technology leader

The invention relates to a medical appliance, and in particular to a dilator for forming a cavity in a push body. Background technique

Compression fractures of the spine caused by osteomyelitis are highly treatable. At present, the use of bulbar device for expansion and kyphoplasty to treat spinal compression fractures has achieved satisfactory early results.

This special ball grate device includes a balloon provided at the front end of a hollow rod body, and the rear end of the rod body is connected to a high-pressure syringe with a pressure measurement and control device and a pumping and vacuuming device. In the plastic surgery, the percutaneous puncture is guided by the "C" arm X-ray machine through the push bow to enter the wound push, the hollow drill is drilled into the wound push under the guide of the guide pin, and a working channel is established, and then sent to the special through the working channel. High pressure resistant ball saccade, under the observation of "C" arm X-ray machine, use a high pressure syringe with pressure measuring and control device to inject the contrast agent into the ball saccade to expand the ball saccade, restore the height of the injury and correct the kyphosis. The ball pupa is evacuated and exited, leaving the cavity generated after the ball pupa expands. Finally, the bone cement is injected into the cavity under low pressure to form a casting in the cavity to complete the operation. Compared with the traditional push-back kyphoplasty, the bulbar expansion and push-back kyphoplasty can squeeze the collapsed cancellous bone fractured due to osteoporosis to the upper and lower end plates of the pusher and the surrounding cortex To make it compact and restore the height and shape of the wound push, and then inject bone cement into the surrounding complete cavity, so it not only increases the effectiveness of the push reset, but also fundamentally avoids the simple push push operation The potential danger caused by bone cement leakage also effectively reduces complications.

However, this special ball ball needs to bear a lot of pressure during the operation, so the ball ball must be made of a special material ^ cattle warp special manufacturing process, and the cost is higher. At the same time, because the bulbar material does not have a clear image under the X-ray and its expansion principle, the bulbar also needs to be equipped with a high-pressure syringe with a pressure measurement and control device to inject contrast agent to make the bulbar expansion and contrast clear. At the same time, it is also necessary to be equipped with a pumping and pumping device to draw out the contrast medium and achieve a vacuum state of the bulb. The configuration of these components will inevitably make the bulb device high.

On the other hand, because the bulb is expanded by injecting a contrast agent, and because of the soft characteristics of the bulb, the shape of the cavity formed by the expansion cannot be accurately controlled, depending on how small the contrast is injected. The shape of the chamber formed by the pressure and speed is random, which is not accurate and stable enough. Physicians need a lot of artificial views under the guidance of X-ray machines during plastic surgery. Observe the expansion, reduction, and injection of bone cement. Because the volume of the cavity cannot be accurately grasped, the amount of injected bone cement basically depends on the surgeon's surgical experience and can be compared with X-ray guidance. Good grasp, the operation is more difficult. In addition, in order to form a cavity in the injury push by using the ball, it is necessary to inject t-agent under pressure monitoring. When the ball is expanded, the contrast agent needs to be drawn out again, and the operation process is very complicated.

On the last hand, this ball is a soft material after all. During the operation, it not only has to bear a large expansion pressure, but also touches the thorn-shaped cancellous bone, which is relatively easy to break. Rupture and the leakage of the contrast medium inside the wound will cause the operation to fail, seriously threaten the patient's health and even life safety, and there are hidden safety hazards. Summary of the invention

An object of the present invention is to provide a dilator for forming a cavity in a push body, which can greatly reduce costs, simplify a surgical procedure, and can ensure extremely high safety.

Another object of the present invention is to provide a dilator for forming a cavity in a push body, which can accurately reflect the volume formed by the cavity, and is convenient for the injection amount of the bone shield filler into the grip.

The technical solution of the present invention is as follows: A dilator for forming a cavity in a push body, which is characterized in that it consists of a hollow outer tube and an inner tube passing through the hollow outer tube. One end is fixed, and the outer tube is provided with an elastic expansion section at the fixed ends of the two tubes, and the other ends of the two tubes are movably sleeved.

As a further improvement of the present invention, the movable sleeve ends of the two tubes are provided with a scale line reflecting the volume of the elastic expansion section.

During the use of the present invention, a relative axial position movement between the inner tube and the outer tube can be caused by the movable sleeve end, so that the elastic expansion section of the outer tube can be expanded to form a cavity, because the present invention only uses two It consists of a sleeve fitting fixed at one end and an opening strip is provided on the outer tube, so the manufacturing cost will be greatly reduced; and only the invention needs to be inserted from the catheter, and the inner tube can be adjusted by moving the sleeve end to make the elasticity The expansion section is expanded to form a cavity, which reduces the existing bulbs and requires a high-pressure syringe with a pressure measuring device and a pumping and aspiration device, which greatly reduces the cost, and simplifies the surgical procedure because no contrast agent is needed. Since the elastic expansion section of the present invention is a kind of opening bar, as long as the expander is properly rotated during the expansion of the elastic expansion section, a satisfactory cavity can be formed, and the safety is extremely high.

In addition, since the present invention is provided with a tick mark at the movable sleeve end, in this way, Observing the volume of the cavity formed by the outward expansion of the elastic expansion section is convenient for the physician to grasp the amount of bone filling injection, and can reduce the difficulty of the operation to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of an unused embodiment in which a straight strip-shaped opening strip and a threaded structure cooperate according to the present invention. FIG. 2 is a perspective view of an unused state of the embodiment shown in FIG. 1 of the present invention.

FIG. 3 is a schematic diagram of an embodiment in which a fixed end of an inner tube protrudes from an outer tube in the present invention.

FIG. 4 is a schematic diagram of an embodiment in which the opening strip is in the shape of an oblique strip.

FIG. 5 is a schematic diagram of an embodiment in which the opening strip has a solitary shape.

FIG. 6 is a schematic diagram of an embodiment in which the opening strip is curved.

FIG. 7 is a diagram of a spring according to an embodiment of the present invention with wide and narrow openings. FIG. 8 is a schematic diagram of the elastic expansion of the embodiment in which the opening strips are arranged irregularly in the present invention. FIG. 9 is a schematic diagram of an embodiment in which an inner tube is provided with a screwing piece at a holding end according to the present invention.

FIG. 10 is a schematic diagram of an embodiment in which a convex ring is provided on the holding end of the inner tube in the present invention.

FIG. 11 is a schematic diagram of an embodiment in which an inner tube is provided with a nut on a threaded section of a holding end according to the present invention. FIG. 12 is a schematic diagram of an embodiment in which the outer tube is omitted at the movable sleeve end according to the embodiment of the present invention.

FIG. 13 is a front view of a use state of the embodiment shown in FIG. 1 of the present invention.

FIG. 14 is a perspective view of a use state of the embodiment shown in FIG. 1 of the present invention.

FIG. 15 is a schematic diagram of an operation process of inserting a wound push in the embodiment shown in FIG. 1 of the present invention.

FIG. 16 is a schematic diagram of an operation process of expanding the cavity in the embodiment of FIG. 1 to form a cavity. FIG. Π is an enlarged schematic view of a portion A where a tick mark is provided in FIG. 6 of the present invention.

FIG. 18 is a schematic diagram of an embodiment in which the scale line is provided on the outer tube in the present invention.

FIG. 19 is a schematic diagram of another embodiment in which the scale line is provided on the outer tube in the present invention.

FIG. 20 is a schematic diagram of a third embodiment in which the scale line is provided on the outer tube in the present invention.

FIG. 21 is a schematic diagram of an embodiment in which a scale line is simultaneously provided on an end face of a grip portion of an outer tube in the present invention. FIG. 22 is a schematic diagram of an embodiment in which scale lines are simultaneously disposed on the peripheral surface of the outer tube holding portion in the present invention. FIG. 23 is a schematic diagram of an embodiment in which the outer tube is made of a transparent material in the present invention.

FIG. 24 is a schematic diagram of an embodiment where the elastic expansion section is a double-layer pipe section in the present invention.

FIG. 25 is a schematic diagram of an embodiment in which the opening strip of the double-layer pipe section is straight. FIG. 26 is a schematic diagram of a spring expansion according to an embodiment in which the opening strip of a half pipe section is in an oblique strip shape. FIG. 27 is a schematic diagram of elastic expansion of an embodiment in which the opening strip of the J½ pipe section has an arc shape. Fig. 28 is a schematic diagram of an embodiment in which the opening strip of the pipe section in the present invention has a curved shape! FIG. 29 is a schematic diagram of an embodiment in which an axial positioning structure is provided at a movable sleeve end in the present invention. FIG. 30 is a schematic diagram of an embodiment in which a concave-convex structure is used at the movable sleeve end in the present invention. FIG. 31 is a schematic diagram of another embodiment in which a concave-convex structure is used at the movable sleeve end in the present invention. detailed description

Example 1

Referring to FIGS. 1 and 2, a dilator for forming a cavity in a push body provided by the present invention is composed of a hollow outer tube 1 and an inner tube 2 passing through the hollow outer tube 1. The inner tube 2 The end portion 21 is fixed to the end portion 11 of the hollow outer tube 1, the fixed end portion 21 of the inner tube 2 is retracted inside the fixed end portion 11 of the outer tube 1, or may protrude from the outer tube 1 to a certain distance, as shown in FIG. 3 As shown. For the fixed form of the inner tube end portion 21 and the outer tube end portion 11, can be welded or screwed or two tubes integrally formed, in short, as long as the inner tube can be linked to the fixed structure of the end portion 11 of the outer tube 1 can be. use. The outer tube 1 is provided with elastic expansion sections 12 at the fixed ends of the two tubes, and the other ends of the two tubes 1 and 2 are movably sleeved.

In this embodiment, the elastic expansion section 12 is composed of a single-layer tube section with a certain length integrally formed on the outer tube 1, and a plurality of opening strips 3 are provided on the single-layer tube, and the opening strip 3 is axial with the outer tube 1. Parallel straight bars, as shown in Figures 1-3. Referring to FIG. 4, the opening strip 3 may also be in an inclined strip shape at a certain angle with the axial direction of the outer tube 1. Referring to FIGS. 5 and 6, the opening strip 3 may also be an arc-shaped strip or a curved strip that extends substantially along the axial direction of the outer tube 1, and can also achieve the effect of expanding into a cavity, and the arc-shaped or curved The shaped opening strip 3 can also better ensure the flatness of the cavity wall surface. In the structure shown in FIG. 1 to this embodiment, the widths of the opening bars 3 are equal. In addition, referring to FIG. 7, the widths of the opening strips 3 may also be unequal, and a regular arrangement in which the wide opening strips 31 in the circumferential direction and the narrow opening strips 3 are spaced apart is shown. Referring again to FIG. 8, each of the opening bars 3 and 31 exhibits an irregular arrangement state. This irregular arrangement includes irregular opening widths of the opening bars, and irregular distribution of the circumference of the opening bars of different widths. In short, the elastic expansion section 12 provided by the present invention is an expansion structure in which an opening strip is provided on the hollow outer tube 1. Therefore, as long as the opening strip 3 is provided on the hollow outer tube 1, the expansion can be formed. The opening width, number, and distribution in the circumferential direction may not be limited. Based on this, even the hollow outer tube 1 can be provided with only two opening strips to achieve external expansion to form a cavity, such as along the axial direction of the outer tube 1 Two openings are provided at the radial positions, that is, the opening strip 3 presents two fan-shaped pieces, and the drawings are omitted. However, it should be noted that the width of the opening strip 3 cannot be too thin, otherwise the formation of the cavity may be affected.

In this embodiment, as shown in FIGS. 1 to 8, the inner tube 2 protrudes from the hollow outer tube 1 at a movable sleeve end to a certain length to form a holding end 22. For the convenience of holding, the outer tube 1 may also be at this end. An enlarged grip portion 13 is provided. Of course, if the tube 1 is provided with a large inner concave hole at the movable sleeve end, the inner tube 2 may not protrude, as long as it can hold the inner tube 2 and move it relative to the outer tube 1, The drawings are omitted.

The movable sleeves of the two tubes are set to be threaded. As shown in FIG. 4, the inner tube 2 is provided with a certain length of external threads 221 on the holding end 22, and the inner wall of the holding portion 13 is provided with internal threads 131. Further, referring to Figs. 9 and 10, in order to make it easier to rotate the inner tube 2, the inner tube 2 is further provided with an adjusting member 24. The adjusting member 24 is a screwing piece 241 or a convex ring 242 provided at the extreme end of the inner tube 1. The screwing piece 241 and the convex ring 242 can be assembled after the dilator of the present invention is formed, and can also be manufactured at the time of manufacture. It is integrally formed, and pinching the screwing piece 241 or the convex ring 242 can make rotating the inner tube 1 more convenient. In addition, referring to FIG. 11, the adjusting member 24 may also be a nut 243 provided on the outer thread section 221 of the inner tube 2. When the nut 243 is rotated, the outer tube 1 and the inner tube 2 can be forced to move in a relative position. The nut 243 can adjust the relative axial position movement of the two pipes, and can also play a positioning role to prevent the axial position movement of the two pipes. Obviously, the enlarged grip portion 13 provided on the movable sleeve end of the outer tube 1 can also be omitted, as shown in FIG. 12.

In use, referring to FIGS. 13 and 14, the inner tube 2 or the outer tube 1 is rotated by a threaded structure at the movable sleeve end to move the two in a relative axial position, so that the elastic expansion of the outer tube 1 can be achieved. The segment 12 expands outward to form a cavity. Since the present invention is only composed of two sleeve fittings fixed at one end and an opening strip 3 is provided on the outer tube 1, the manufacturing cost is greatly reduced; see FIGS. 15 and 16, because only the dilator of the present invention needs to be contained in the catheter. Inserting and rotating the inner tube 2 or the outer tube 1 can expand the elastic expansion section 12 to form a cavity, which simplifies the surgical procedure and the difficulty of operation. Since the elastic expansion section 12 itself is composed of a plurality of opening bars 3, as long as the expander is properly rotated during the expansion of the elastic expansion section 12, a satisfactory cavity can be formed, and the safety is extremely high.

As a further improvement of the present invention, referring to FIGS. 6 and 17, a scale line 23 reflecting the volume of the elastic expansion section 12 is provided at the movable sleeve end of the two pipes, and the scale line 23 is provided on the outer wall of the inner pipe 2. In this embodiment, The scale line 23 can be set on the external thread section 221 of the holding end 22 of the inner tube 1, and the recording scale can be observed at the same time when the thread structure is rotated. With experience, the bone filling material injected by most patients is basically 5 ml, and the upper limit of the mark Π can be set to 5 ml. The upper limit of the scale 23 is tailored to a specific patient. Referring to FIGS. 18 and 19, the scale line 23 may also be provided on the outer wall of the outer tube 1, and the visible portion 14 is provided at a position corresponding to the scale line ^{23 of the} outer tube 1, and the inner tube 2 is provided opposite to the outer tube. 1 scale line 23 and the size reference 231 of the visible part 14, in this structure, the viewable part 14 of the outer tube 1 is a transparent section 141 or an axially long through hole 142, and the size reference 231 of the inner tube 2 For the eye-catching color line segment 2311 or the circumferential color ring 2312 corresponding to the transparent segment 141 or the through-hole 142, various eye-catching or alert colors that can be easily recognized by the eye can be adopted, such as red, yellow, blue, black, etc .; Alternatively, referring to FIG. 20, the visible part of the outer tube 1 may also be set as the aforementioned axially long through hole 142, and the size reference 231 of the inner tube 2 may be a pointer 2313 protruding from the through hole 142. In addition, referring to FIGS. 21 and 22, the scale line 23 may also be provided on an end surface 132 or an outer peripheral surface 133 of the holding portion 13 of the outer tube 1. In short, the scale line 23 can be set at any position of the movable sleeve end of the two tubes. As long as it can reflect the volume of the cavity, there is no restriction on the position of the scale line 23.

The outer tube 1 and the inner tube 2 of the present invention can be made of various materials such as polymer materials or metals, can produce clear contrast during surgery, and can be widely used in a variety of medical fields that need to form a cavity. Plastics or plastic mixtures or resins in polymer materials not only have good elastic deformation characteristics, but also have low cost. At the same time, for transparent or translucent plastics or plastics mixtures or resin materials, when the scale 23 is set outside When the tube 1 is on, it is not necessary to additionally provide a visible portion 14 on the outer tube 1, as shown in FIG. 23. However, for the outer tube 1 of metal material, a visible portion 14 needs to be provided.

Because the scale line 23 is set, and the two pipes are threaded at the movable sleeve end, this not only can more intuitively grasp the cavity volume, facilitate the grasp of the bone cement injection volume, but also can be rotated by holding the end 22 or the grip. The holding portion 13 can also control the volume of the cavity from the precision of the fine adjustment. The shape of the cavity is basically fixed because the opening strip 3 has a certain rigidity. If the opening length of the opening strip 3 and the elastic distribution state are changed, The shape and volume of the cavity can be controlled artificially. Therefore, it is also convenient for the physician to grasp the injection amount of the bone filler, which can reduce the difficulty of the operation to a certain extent. Example 2

This embodiment is basically the same in structure, material, principle, use process and effect as in Embodiment 1. The same points will not be repeated, and only the differences will be described in detail.

One of the differences. Referring to FIG. 24, compared to the single-layer pipe section with elastic expansion 12 in Embodiment 1, the elastic expansion section 12 in this embodiment is composed of a double-layer sleeve section 4 provided at a certain length on the outer pipe 1. double Layer ^ Shu pipe inner tube section ⁴¹ of the floor sections 42 are set to the number of sheets tear strip 411, 421, and the inner tube section a tear strip 41 of the opening 411 of the tear strip 11 and the outer tube section 42 of the opening 421 of the 4211 phase shifted. The outer pipe section 42 is fixedly sleeved on the outside of the inner pipe section 41 to form the double-layered pipe section 4. For example, the outer pipe section 42 can be implemented by attaching the outer pipe section 42 to the single-layer pipe in Embodiment 1. .

In this way, during the process of expanding the elastic expansion section 12 to form a cavity, the opening strips 411 and 421 of the two layers will form a continuous expansion wall surface without gaps because the openings 4111 and 4211 are staggered, thereby eliminating the need for The operation of the rotating dilator during the operation is more convenient to use, and can evenly collapse the collapsed cancellous bone to the upper and lower end plates of the pusher and the surrounding cortex, making it less permeable when injecting bone filler. Leakage, better safety.

In this embodiment, the opening width, number, and distribution along the circumferential direction of the opening strips 411 and 421 of the two-layer pipe sections 41 and 42 are exactly the same as those of the embodiment 1. However, it should be noted that the two-layer opening strips 411 and 421 of this embodiment The openings 4111, 4211 should stagger this feature. Referring to FIG. 25, for the straight opening strip parallel to the axial direction of the outer tube 1, the openings 4111 and 4211 of the two opening strips 411 and 421 should be staggered to form a continuous or closed expansion wall surface during the expansion process. See Figure 26, for the oblique strip-shaped opening strip at a certain angle to the axial direction of the outer tube 1, the openings 4111, 4211 of the two-layer opening strips 411, 421 can be staggered by a certain angle or the opposite tilt directions; see Figure 27, For curved strip-shaped opening strips 411, 421 that are substantially along the axis of the outer tube 1, the openings 4111, 4211 are staggered at an angle or opposite in the bending direction; see FIG. 28. For the curved strip-shaped opening strips, the curve The openings are opposite or out of phase. In this way, a more complete expanded wall surface can also be generated, and the surgical effect is better.

The second difference is that, compared with the threaded fit of the two tubes in the first embodiment, the two tubes in this embodiment adopt a sliding fit at the movable sleeve end. Referring again to FIG. 24, the sliding fit is a clearance fit, and a transition fit may also be used. A guide length of a certain length may be provided at the gap or the transition fit pipe section, so that the inner hole of the tube 1 can communicate with the inner tube 2 The outer wall has a contact surface of a certain length, and has good guiding property. For this gap or transition fit structure, when the elastic expansion section 12 is expanded to a certain extent to form a satisfactory cavity, the inner tube 1 and the outer tube 2 will not continue to generate axial relative movements and destroy the satisfaction formed. The cavity is preferably provided with an axial positioning structure 5 at its movable sleeve end. Of course, if the positioning structure is not provided, it is also possible for the participants participating in the operation to manually support and support.

Referring to FIG. 24, the axial positioning structure 5 is an elastic locking piece 51 which is clipped on the inner tube 2. In a state where the elastic expansion section 12 is expanded outward to form a satisfactory cavity, the elastic locking piece 51 is clamped on the holding end 22 of the inner tube 2 to restrict the relative axial position of the two tubes from moving. Referring to FIG. 29, the axial positioning structure 5 may also be an elastic positioning structure 52 provided at the movable sleeve end of the outer tube 1, which includes a plurality of axial elastic pieces 521, and at least two opposite elastic pieces 521 are provided with A stopper 5211 is sleeved on the outside of the elastic piece 521 with a positioning ring ^522. The inner diameter of the positioning ring 522 is smaller than the circumference diameter of the elastic piece 521 and slightly larger than the outer diameter of the inner tube 2. When the elastic expansion section 12 is expanded outward to form a satisfactory cavity, the positioning ring 522 is moved in the direction of the stopper 5211 and tightly sleeved on the outer periphery of each elastic piece 521. By the friction effect of the jacket portion, the two tubes can be restricted Relative axial position. Of course, for the axial positioning structure 5, other structures capable of achieving axial positioning in other conventional technologies may be adopted.

In addition, the sliding fit can also be an interference fit. Due to this tight fit, a relatively large operating force is required in the process of the two tubes moving in relative positions to form the cavity from the elastically expanded section 12 to expand outward, but This interference fit has a good axial positioning effect, and the axial positioning structure can be omitted.

In this embodiment, the inner tube 2 can be directly withdrawn or the outer tube 1 can be pushed out at the movable end, and a satisfactory cavity can be formed under the guidance of the scale line 23 and the X-ray machine, and the operation is very convenient and simple. Example 3

This embodiment is basically the same in structure, material, principle, use process and effect as those in Embodiments 1 and 2. The same points will not be repeated, and only the differences will be described in detail. In cooperation with sliding, the two tubes in this embodiment adopt a concave-convex structure at the movable sleeve end.

Referring to FIGS. 30 and 31, the concave-convex structure 6 includes several circumferential grooves 61 provided on the inner diameter of the outer tube 1 and a convex ring 62 provided on the outer diameter of the inner tube 2 to cooperate with the groove of the outer tube 1; or, a groove The positions of 61 and the convex ring 62 are interchangeable, that is, the inner diameter of the outer tube 1 is provided with several convex rings 62, and the outer diameter of the inner tube 2 is provided with a matching circumferential groove 61.

Finally, it should be noted that the embodiments provided by the present invention are only a few feasible embodiments, and there are also many other embodiments composed of the combination of these features, for example, the double expansion of the elastic expansion section. The combination of the layered pipe segment structure and the thread fit, or the combination of the single-layer pipe segment structure and the sliding structure, or the combination of the single-layer pipe segment and the concave-convex structure, etc., will not be enumerated in detail. The structure of the embodiment provided by recombining various technical features should also be regarded as the structure provided by the present invention. Since each technical feature of the present invention has been disclosed in the drawings, various possible reorganized implementations are not drawn. For example drawings, no corresponding text description is provided.

Claims

Claim

1. A dilator for forming a cavity in a push body, characterized by comprising a hollow outer tube and an inner tube passing through the hollow outer tube, the two tubes being fixed at one end, and The tubes are provided with elastic expansion sections at the fixed ends of the two tubes, and the other ends of the two tubes are movably sleeved.

2. The dilator for forming a cavity in a push body according to claim 1, wherein the elastic expansion section is composed of a single-layer pipe section provided at a fixed length of the outer pipe, and the single-layer pipe section is Several opening strips are provided.

3. The dilator for forming a cavity in a push body according to claim 1, wherein the elastic expansion section is composed of a double-layer sleeve section provided at a certain length of the outer tube, and the double-layer sleeve It is assumed that a plurality of opening strips are provided in the pipe sections, and the openings of the opening strips of the two layers of pipe sections are staggered.

The dilator for forming a cavity in a push body according to claim 2 or 3, wherein the opening strip is in a straight shape parallel to the axial direction of the outer tube; or, the opening strip It is in the shape of an oblique strip at a certain angle to the axial direction of the outer tube; or, the opening strip is in the shape of an arc or a curved strip substantially along the axial direction of the outer tube. .

5. The dilator for forming a cavity in a push body according to claim 2 or 3 or 4, wherein the widths of the opening bars are equal.

6. The dilator for forming a cavity in a push body according to claim 2 or 3 or 4, wherein the widths of the opening bars are not equal, and the opening bars of different widths are circumferentially spaced. Regular or irregular.

7. The dilator for forming a cavity in a push body according to any one of claims 1-3, wherein the elastic expansion section is integrally formed on the outer tube wall or is connected to the outer tube in combination On the wall.

8. The dilator for forming a cavity in a push body according to any one of claims 3, wherein the fixed end of the inner tube is retracted into the fixed end of the outer tube; or The fixed end of the tube projects a distance from the outer tube.

9. The dilator for forming a cavity in a push body according to any one of claims 1-3, wherein the inner tube protrudes from the hollow outer tube by a certain length at the movable sleeve end Hold the end.

10. The dilator for forming a cavity in a push body according to claim 9, characterized in that the movable sleeve of the two tubes at the movable sleeve end uses a threaded fit at the holding end of the inner tube Assume A certain length of external thread is provided, and the external tube is provided with an internal thread correspondingly.

The dilator for forming a cavity in a push body according to claim 9 or 10, wherein the holding end of the inner tube is provided with an adjusting member.

12. The dilator for forming a cavity in a pusher body according to claim 11, wherein the adjusting member is a screwing piece or a convex ring provided on an end of the inner tube or a screw provided on the inner tube. Segmented nuts.

13. The expander for forming a cavity in a push body according to any one of claims 9-12, wherein the outer tube is provided with an enlarged grip portion at a movable sleeve end.

14. The dilator for forming a cavity in a push body according to claim 9, wherein the movable sleeve of the two tubes at the movable sleeve end adopts a sliding fit.

15. The dilator for forming a cavity in a push body according to claim 14, wherein the sliding fit is a clearance fit.

The dilator for forming a cavity in a push body according to claim 14, wherein the sliding fit is a transition fit or an interference fit.

The dilator for forming a cavity in a push body according to claim 16, wherein a guide section of a certain length is provided at the transition fit.

18. The dilator for forming a cavity in a push body according to claim 14, wherein the inner tube and the hollow outer tube are provided with an axial positioning structure at an unfixed end.

19. The dilator for forming a cavity in a push body according to claim 18, wherein the axial positioning structure is an elastic locking piece that is clipped on the inner tube.

20. The dilator for forming a cavity in a push body according to claim 18, wherein the axial positioning structure is an elastic positioning structure, which includes a plurality of provided at an unfixed end of the outer tube. An axial elastic piece, and at least two opposite elastic pieces are provided with stoppers, and a positioning ring is sleeved on the outside of the outer tube elastic piece; the inner diameter of the positioning ring is smaller than the circumferential diameter of the outer tube elastic piece; Greater than the outer diameter of the inner tube.

21. The dilator for forming a cavity in a push body according to claim 9, wherein the two tubes are fitted with a concave-convex structure at the movable sleeve end.

22. The dilator for forming a cavity in a pusher body according to claim 21, wherein the concave-convex structure includes a plurality of circumferential grooves provided on an inner diameter of the outer tube, and A convex ring matched with a concave ring of the outer tube; or the concave-convex structure includes a plurality of channels provided on the inner diameter of the outer tube A convex ring and a circumferential groove provided on the outer tube with an outer diameter matching the convex ring.

23. The dilator for forming a cavity in a push body according to any one of the preceding claims, wherein the movable sleeve ends of the two tubes are provided with a scale line reflecting the volume of the elastic expansion section.

24. The dilator for forming a cavity in a push body according to claim 23, wherein the scale line is provided on an outer wall of the inner tube.

25. The dilator for forming a cavity in a push body according to claim 23, wherein the scale line is provided on the outer wall of the outer tube, and a visible portion is provided at the scale line, and the inner tube is A size reference is provided relative to the outer tube scale and the visible part.

26. The dilator for forming a cavity in a push body according to claim 25, wherein the visible part of the outer tube is a transparent or axially long through hole, and the inner tube The size reference is the eye-catching color line segment or the circle color circle corresponding to the transparent segment or the through hole.

27. The dilator for forming a cavity in a push body according to claim 25, wherein the visible portion of the outer tube is an axially long through hole, and the size reference of the inner tube is A pointer protruding from the portion of the through hole.

The dilator for forming a cavity in a push body according to claim 23, wherein the scale line is provided on an end surface or an outer peripheral surface of a grip portion of an outer tube.

29. The dilator for forming a cavity in a push body according to any one of the preceding claims, wherein the outer tube and the inner tube are made of a polymer material or a metal material.

30. The dilator for forming a cavity in a push body according to claim 29, wherein the polymer material is a transparent plastic or a plastic mixture or a tree moon.