Telescopic channel opening device

Abstract

The utility model provides a telescopic channel opening device which comprises N sleeves, the N sleeves are sequentially arranged in a sleeved mode and are named as a first-stage sleeve, a second-stage sleeve... an Nth-stage sleeve, the Nth-stage sleeve is located on the outermost layer, the first-stage sleeve is located on the innermost layer, and N is larger than or equal to 3; the limiting assembly comprises limiting grooves formed in the sleeves and limiting balls which are arranged on the adjacent inner-layer and outer-layer sleeves and can rotate freely, and the limiting balls can be matched with the limiting grooves under the action of external force to achieve step-by-step extension or retraction of the adjacent sleeves; the control assembly is arranged between the partial sleeves and used for limiting the sliding range between the partial sleeves, and it is guaranteed that the N-1 sleeves stretch out and draw back step by step. The first-stage sleeve is pressed, and through cooperation of the limiting assembly and the control assembly, the sleeves can extend outwards or retract inwards step by step under the action of external force. The telescopic channel distraction device solves the technical problems that in a traditional operation in the prior art, the speed of manually establishing a channel is low, and the operation time is long.

Description

TECHNICAL FIELD

[0001] The utility model relates to medical instrument technical field, concretely relates to a telescopic passageway distraction device. BACKGROUND

[0002] In the current minimally invasive spinal fixation surgery or laminectomy surgery, a passageway is usually needed to be established so that the slender surgical instruments (such as surgical forceps or endoscopes) can smoothly enter the surgical area and protect the surrounding soft tissues. The traditional method usually uses a multi-stage distraction device to manually expand the incision step by step to establish a suitable surgical passageway. However, this step-by-step expansion method is complicated and time-consuming, often requiring the surgeon to manually operate within a limited time, which may result in prolonged surgery time and limited operation precision.

[0003] With the development of surgical automation and intelligentization technology, the traditional manual passageway distraction device has been unable to meet the requirements of modern intelligent surgical equipment for efficiency and precision. The current technology is difficult to provide a fast, accurate and convenient passageway distraction method, which also limits the time control and precise operation during the surgery.

[0004] Therefore, the prior art needs to be further developed. SUMMARY

[0005] The utility model aims at overcoming the above technical deficiencies, providing a telescopic passageway distraction device to solve the technical problems of slow speed of manual establishment of passageway and long surgery time in related technology.

[0006] To achieve the above technical purpose, the utility model adopts the following technical scheme: a telescopic passageway distraction device is provided, comprising: N sleeves, the N sleeves are sequentially sleeved and respectively named as the first-stage sleeve, the second-stage sleeve……the N-stage sleeve, wherein the N-stage sleeve is located at the outermost layer, the first-stage sleeve is located at the innermost layer, and N≥3; a limiting component, the limiting component comprises a limiting groove provided on each sleeve and a limiting ball provided on the adjacent inner and outer sleeves and freely rotatable, the limiting ball can realize the step-by-step extension or retraction of the adjacent sleeves under the action of external force in cooperation with the limiting groove; a control component, the control component is provided between part of the sleeves to limit the sliding range between part of the sleeves and ensure the step-by-step extension and retraction of N-1 sleeves; the first-stage sleeve is pressed, the sleeve can be step-by-step extended outward or retracted inward under the action of external force through the cooperation of the limiting component and the control component.

[0007] Further, the control assembly comprises control grooves arranged on the first sleeve to the N-1 sleeve respectively and limiting posts fixed on the inner walls of the second sleeve to the N sleeve respectively and matched with the control grooves on the sleeves, the limiting posts move in the control grooves when the sleeves move, thereby limiting the sliding range of the corresponding sleeves.

[0008] Further, the limiting balls are arranged through the side walls of the second sleeve to the N-1 sleeve, the limiting grooves comprise first limiting grooves and second limiting grooves, the limiting balls are matched with the first limiting grooves on the adjacent outer sleeves, the first limiting grooves are arranged on the inner walls of the third sleeve to the N sleeve, for limiting when the sleeves extend outward, the limiting balls are matched with the second limiting grooves on the adjacent inner sleeves, the second limiting grooves are arranged on the outer walls of the first sleeve to the N-2 sleeve, for limiting when the sleeves retract inward.

[0009] Further, the first limiting grooves are curved grooves, so that the limiting balls smoothly enter the second limiting grooves after being extruded by the adjacent outer sleeves when the sleeves retract; the inner walls of the second limiting grooves are flat, for preventing the sleeves from sliding due to external interference.

[0010] Further, two limiting balls are arranged on the side walls of each sleeve along the opposite sides thereof symmetrically.

[0011] Further, the limiting balls on all the sleeves are in the same plane, thereby ensuring that the limiting assembly is uniformly stressed.

[0012] Further, one control groove is arranged on each opposite side of each sleeve, the control grooves on the opposite sides are in the same plane; the planes where the control grooves of the adjacent sleeves are located are perpendicular to each other, thereby making the control grooves of the adjacent sleeves staggered, so as to avoid interference when the sleeves move.

[0013] Further, the first spring is fixed at one end to the interiors of the N sleeves and connected at the other end to the first sleeve, for pushing the sleeves to extend outward step by step under the elastic force.

[0014] Further, the unlocking assembly comprises an unlocking rod capable of passing through the N sleeve, a second spring sleeved on the unlocking rod and a fixing hole arranged on the N-1 sleeve, the second spring is used for pushing the unlocking rod to move when the N-1 sleeve retracts, the unlocking rod automatically pops into the fixing hole when the N-1 sleeve retracts to the specified position; when the unlocking rod is inserted into the fixing hole, the sleeves are limited in the retracted state; when the unlocking rod leaves the fixing hole, the N-1 sleeve is released, so that the sleeves extend step by step under the external force.

[0015] Further, a retaining sleeve is detachably sleeved on the outer wall of the Nth sleeve; when the first sleeve reaches the surgical position, the sleeves are sequentially retracted and withdrawn by pressing the first sleeve, so that the retaining sleeve is retained at the surgical site to provide an operation channel for the surgery.

[0016] Advantages:

[0017] 1. The device can automatically extend or retract the multiple sleeves under the action of external force through the cooperation of the limiting assembly and the control assembly, without the need for manual step-by-step adjustment, simplifying the operation process of the channel expansion, greatly shortening the surgical preparation time, and improving the surgical efficiency.

[0018] 2. The control assembly can effectively limit the sliding range of the sleeves through the cooperation of the control groove and the limiting column, avoiding unnecessary interference caused by excessive movement of the sleeves. Meanwhile, the bilateral limiting design of the limiting ball and the limiting groove can ensure the accuracy of the channel extension and retraction, and ensure smooth operation of the surgical instruments.

[0019] 3. The limiting balls on all sleeves are in the same plane, and the limiting and sliding of the sleeves are uniformly stressed, avoiding the device jamming or misplacement problem caused by uneven force, and improving the reliability and stability of the device.

[0020] 4. The first limiting groove adopts a curved groove design, which facilitates smooth sliding of the limiting ball; the second limiting groove adopts a flat design, which effectively avoids sliding errors of the sleeves caused by external disturbance, and the overall structure is rigorous and the operation is convenient.

[0021] 5. The design of the elastic force of the first spring and the auxiliary unlocking of the second spring not only improves the operation efficiency of the device, but also reduces the need for human force, making the device more energy-efficient. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a sectional view of the extended state of the telescopic channel expansion device adopted by the embodiment of the utility model;

[0023] Figure 2 is a sectional view of the retracted state of the telescopic channel expansion device adopted by the embodiment of the utility model;

[0024] Figure 3 is a structural schematic view of the control ball of the telescopic channel expansion device adopted by the embodiment of the utility model;

[0025] Figure 4 is Figure 1 is a local enlarged view of part A in figure 6;

[0026] Figure 5 is a connection state diagram of the telescopic sleeve and the retaining sleeve adopted by the embodiment of the utility model;

[0027] Figure 6 is the disassembled state diagram of the telescopic sleeve and the indwelling sleeve adopted by the embodiment of the utility model.

[0028] Among them, the above-mentioned drawing includes the following figure marks:

[0029] 1, sleeve; 11, first stage sleeve; 12, second stage sleeve; 13, third stage sleeve; 14, fourth stage sleeve; 15, fifth stage sleeve; 16, sixth stage sleeve; 17, seventh stage sleeve; 18, notch; 2, limiting assembly; 21, limiting ball; 22, first limiting groove; 23, second limiting groove; 3, control assembly; 31, control groove; 32, limiting column; 4, unlocking assembly; 41, unlocking rod; 42, second spring; 43, fixing hole; 5, indwelling sleeve; 6, first spring. DETAILED DESCRIPTION

[0030] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present application.

[0031] According to the utility model embodiment, a telescopic passageway distraction device is provided, please refer to Figures 1 to 6 , including: N sleeve 1, N sleeve 1 is set up in turn and is named as first stage sleeve, second stage sleeve... N stage sleeve respectively, wherein, N stage sleeve is located in the outermost layer, first stage sleeve is located in the innermost layer, N is greater than or equal to 3;Limiting assembly 2, limiting assembly 2 includes the limiting groove set on each sleeve and the limiting ball 21 set on the adjacent inner and outer layer sleeve and can rotate freely, limiting ball 21 can realize the step-by-step extension or retraction of adjacent sleeve under the action of external force in cooperation with limiting groove;Control assembly 3, control assembly 3 is set between part of sleeve, for limiting the sliding range between part of sleeve, guarantee N-1 sleeve step-by-step extension and contraction;To the first stage sleeve, through limiting assembly 2 and control assembly 3 cooperation, make sleeve can extend outward or retract inward under the action of external force step by step.

[0032] The stretching device is stretched close to the surgical incision to form a channel around the surgical incision to provide an operation space for the surgery, and the stretching device is more efficient and convenient than manually expanding the incision step by step. The stretching process of the channel stretching device is illustrated by taking N=7 as an example. The process of changing from the retracted state to the stretched state is as follows: the outermost seventh sleeve 17 is used to accommodate and limit the stretching of the inner sleeves, a pushing force is applied to the first sleeve 11 from the inside of the sleeve 1, and since the limiting ball 21 is clamped in the limiting groove, the sixth sleeve 16 is forced to start moving. With the action of the external force, the limiting ball 21 rotates in the limiting groove and drives the sixth sleeve 16 and all the sleeves inside it to slide outward, and when the limiting ball 21 on the sixth sleeve 16 moves to the corresponding position of the limiting groove on the seventh sleeve 17, the limiting ball 21 is forced to slide to stop moving due to the limiting action of the control assembly 3, but the pushing force still exists, forcing the acting force to continue to push the fifth sleeve 15 and all the sleeves inside it to slide outward, at this time the relatively stationary sixth sleeve 16 has a clamping force on the limiting ball 21, and the relatively moving inner sleeve (that is, the fifth sleeve 15) has a pushing force on the limiting ball 21 during the movement, forcing the limiting ball 21 to squeeze into the limiting groove of the relatively opposite sleeve (that is, the seventh sleeve 17), thereby limiting the sixth sleeve 16, and at this time the sixth sleeve 16 completes its stretching action; in this way, until the first sleeve 11 in the innermost layer completes the stretching to realize the stretching action of the entire stretching device. The process of changing from the stretched state to the retracted state is as follows: press the first sleeve 11 to make the first sleeve 11 forced to retract, and since the limiting ball 21 has a clamping force from the limiting groove in the third sleeve, when the limiting groove on the first sleeve 11 moves to the position of the limiting groove on the second sleeve 12, it is forced to stop receiving the limiting action of the control assembly 3, at this time the limiting ball 21 is squeezed into the limiting groove on the first sleeve 11 from the outer sleeve (that is, the second sleeve 12), completing the retraction of the first sleeve 11; then, the external force pushes the second sleeve 12 to continue to retract inward, and the sleeves are unlocked and limited in turn, completing the step-by-step retraction of the sleeves. Through the cooperation of the limiting assembly 2 and the control assembly 3, the sleeves can be stretched outward or retracted inward step by step under the action of the external force, greatly reducing the time for establishing a channel in the surgery. The telescopic channel stretching device of the embodiment solves the technical problems of slow speed and long surgery time in the related art.

[0033] Referring to Figure 1 and Figure 2The control assembly 3 of the telescopic channel dilating device of the embodiment includes control grooves 31 and limiting columns 32. The control grooves 31 are respectively arranged on the first-stage sleeve to the (N-1)-stage sleeve, the limiting columns 32 are respectively fixed on the inner walls of the second-stage sleeve to the N-stage sleeve and matched with the corresponding control grooves 31 on the sleeves, and each sleeve moves to drive the limiting column 32 to move in the control groove 31, thereby limiting the sliding range of the corresponding sleeve. Taking N=7 as an example, the limiting columns 32 are respectively fixed on the inner walls of the second-stage sleeve 12 to the seventh-stage sleeve 17, and the control grooves 31 are arranged on the adjacent inner sleeves (i.e. the first-stage sleeve 11 to the sixth-stage sleeve 16). Through the cooperation of the control grooves 31 and the limiting columns 32, the sliding range of each sleeve can be effectively limited, thereby ensuring the step-by-step movement of the sleeves in the telescopic process, preventing the sleeves from disengaging or mispositioning, improving the stability and reliability of the device. Meanwhile, the telescopic movement of each sleeve is more orderly through the design, and the operation complexity is reduced.

[0034] Referring to Figure 1 and Figure 2 The limiting ball 21 of the telescopic channel dilating device of the embodiment is arranged through the side walls of the second-stage sleeve to the (N-1)-stage sleeve, the limiting groove includes a first limiting groove 22 and a second limiting groove 23, the limiting ball 21 is matched with the first limiting groove 22 on the adjacent outer sleeve for limiting when the sleeve extends outward, and the limiting ball 21 is matched with the second limiting groove 23 on the adjacent inner sleeve for limiting when the sleeve retracts inward. Taking N=7 as an example, the limiting ball 21 is arranged on the side walls of the second-stage sleeve 12 to the sixth-stage sleeve 16, the first limiting groove 22 is arranged on the inner walls of the third-stage sleeve 13 to the seventh-stage sleeve 17 which are adjacent to the outer sleeve of the limiting ball 21, and the second limiting groove 23 is arranged on the outer walls of the first-stage sleeve 11 to the fifth-stage sleeve 15 which are adjacent to the inner sleeve of the limiting ball 21. When the sleeve extends, the limiting ball 21 is extruded into the first limiting groove 22 on the inner wall of the adjacent outer sleeve to limit the extension length, so that the inner sleeve moves outward to extend step by step; when the sleeve retracts, the limiting ball 21 is extruded into the second limiting groove 23 on the outer wall of the adjacent inner sleeve to limit the retraction length, so that the outer sleeve moves inward to retract step by step.

[0035] Referring to Figure 2, The telescopic channel expansion device of the embodiment, the first limiting groove 22 is a curved groove, so that the limiting ball 21 can smoothly enter the second limiting groove 23 after being extruded by the adjacent outer sleeve when the sleeve is retracted; the inner wall of the second limiting groove 23 is flat, which prevents the sleeve from sliding due to external interference. The curved groove design of the first limiting groove 22 allows the limiting ball 21 to be smoothly extruded into the second limiting groove 23 of the inner sleeve during the retraction process of the sleeve. This design reduces the friction and resistance of the limiting ball 21 when changing the limiting position, making the retraction process smoother and more stable. The inner wall of the second limiting groove 23 is flat, which can provide a stable support surface to prevent the sleeve from sliding due to external interference

[0036] Referring to Figure 1 、 Figure 2 and Figure 3 , the telescopic channel expansion device of the embodiment, the side wall of each sleeve is symmetrically provided with two limiting balls 21 along its opposite sides. The symmetrical arrangement of two limiting balls 21 can ensure that the sleeve is uniformly stressed during extension and retraction, avoiding the phenomenon of deflection or jamming caused by unilateral stress.

[0037] Referring to Figure 1 、 Figure 2 and Figure 3 , the telescopic channel expansion device of the embodiment, all the limiting balls 21 on the sleeves are in the same plane, thereby ensuring that the limiting assembly 2 is uniformly stressed. When all the limiting balls 21 on the sleeves are in the same plane, the limiting assembly 2 will be more uniform when stressed.

[0038] Referring to Figure 1 、 Figure 2 and Figure 3 , the telescopic channel expansion device of the embodiment, each sleeve is provided with one control groove 31 on each opposite side, and the control grooves 31 on the opposite sides are located in the same plane; the planes of the control grooves 31 of adjacent sleeves are perpendicular to each other, so that the control grooves 31 of adjacent sleeves are distributed in a staggered manner to avoid interference when multiple sleeves move. The staggered distribution of the control grooves 31 ensures that adjacent sleeves do not interfere with each other during movement.

[0039] Referring to Figure 1 、 Figure 2 and Figure 3The telescopic channel dilating device of the embodiment further comprises a first spring 6, one end of which is fixed inside the N sleeves 1 and the other end is connected with the first sleeve, for pushing the sleeves to extend outwards step by step under the elastic force. The first spring 6 provides power for the automatic extension of the device. When the surgical channel needs to be expanded, the elastic force of the first spring 6 will push the first sleeve 11 outwards, thereby starting the movement of the N-1 sleeve, and further driving the other sleeves to extend out step by step.

[0040] Referring to Figure 1 , Figure 2 and Figure 4 , the telescopic channel dilating device of the embodiment further comprises an unlocking assembly 4, which comprises an unlocking rod 41 capable of passing through the N sleeve, a second spring 42 sleeved on the unlocking rod 41, and a fixing hole 43 provided on the N-1 sleeve, the second spring 42 being used for pushing the unlocking rod 41 to move when the N-1 sleeve is retracted, and the unlocking rod 41 automatically popping into the fixing hole 43 when the N-1 sleeve is retracted to a specified position; when the unlocking rod 41 is inserted into the fixing hole 43, the sleeves 1 are limited in the retracted state; when the unlocking rod 41 leaves the fixing hole 43, the N-1 sleeve is released, allowing the sleeves to extend out step by step under the external force. Taking N=7 as an example, as shown in Figure 2 , when the extending end of the sixth sleeve 16 is retracted to align with the same side end of the seventh sleeve 17, the unlocking rod 41 automatically pops into the fixing hole 43 under the pushing of the second spring 42, achieving reliable locking of the sleeves; when the surgical channel needs to be extended, the unlocking rod 41 is operated to leave the fixing hole 43, which releases the sixth sleeve 16, allowing the sleeves to extend out step by step under the external force.

[0041] Referring to Figure 4 , the end of the sixth sleeve of the telescopic channel dilating device is provided with a cutout 18, which presses down the unlocking rod 41 to store energy for the second spring 42 when the sixth sleeve is retracted, until the unlocking rod 41 enters the fixing hole 43 to release the elastic force, thereby locking the unlocking rod 41.

[0042] Referring to Figure 5 and Figure 6 , the telescopic channel dilating device of the embodiment further comprises a retaining sleeve 5, which is detachably sleeved on the outer wall of the N sleeve; when the first sleeve reaches the surgical position, the sleeves are retracted in turn by pressing the first sleeve, and then the retaining sleeve 5 is pulled out, thereby retaining the retaining sleeve 5 at the surgical site to provide an operation channel for the surgery. Taking N=7 as an example, the retaining sleeve 5 is sleeved on the seventh sleeve 17, and the step-by-step extension of the seven sleeves provides an inner cavity for the retaining sleeve 5, after the seven sleeves are pulled out, the retaining sleeve 5 provides a stable operation channel for the surgery.

[0043] The outermost indwelling sleeve 5 and the seven sleeves 1 of the channel expansion device of the present scheme are used as expansion tools, the indwilling sleeve 5 and the seven sleeves 1 expand the incision together and reach the surgical site, then the seven sleeves 1 exit the human body, leaving the indwelling sleeve 5 to provide operation space for the surgery; the inner wall of the third sleeve 13, the fourth sleeve 14, the fifth sleeve 15, the sixth sleeve 16 and the seventh sleeve 17 of the seven sleeves 1 is provided with a first limiting groove 22, and the outer wall of the first sleeve 11, the second sleeve 12, the third sleeve 13, the fourth sleeve 14 and the fifth sleeve 15 is provided with a second limiting groove 23, and the first sleeve 11 reaches the surgical site such as bone surface or vertebral plate first.

[0044] Before the surgery, the seven sleeves 1 are in the retracted state, and the unlocking assembly 4 needs to be pulled open first to make the sleeves in the elongated state. In the channel expansion stage, the first sleeve 11 enters the incision first, and because the first spring 6 supports behind, it can break through the soft tissue to the bone surface, then the first sleeve 11 cannot advance further, and starts to retract as the sleeves advance. When the end of the first sleeve 11 and the end of the second sleeve 12 are in the same plane, the first sleeve 11 and the second sleeve 12 are relatively fixed due to the action of the limiting column 32, and the limiting ball 21 on the second sleeve 12 is pressed back between the first sleeve 11 and the second sleeve 12, which is used to limit the first sleeve 11 and the second sleeve 12, at this time, the limiting between the second sleeve 12 and the third sleeve 13 is unlocked. With the advancement of each sleeve, the first sleeve 11 and the second sleeve 12 are relatively fixed due to the action of the limiting ball 21 and the limiting column 32, and the first sleeve 11 and the second sleeve 12 are retracted into the third sleeve 13 and the limiting ball 21 between the third sleeve 13 and the fourth sleeve 14 is unlocked. In this way, until the first sleeve 11 to the sixth sleeve 16 are retracted into the seventh sleeve 17. The sixth sleeve 16 is provided with a fixing hole 43, which will be inserted into the unlocking assembly 4 after complete retraction. At this time, the six sleeves complete the process of changing from the elongated state to the retracted state.

[0045] In the process of changing from the retracted state to the extended state, the unlocking assembly 4 needs to be pulled open first. Due to the elastic force of the first spring 6, the spring will first push the first-stage sleeve 11 outward tightly, but the limiting ball 21 between the 1st-stage to 6th-stage sleeves is located in the second limiting groove 23, so the first-stage sleeve 11 to the sixth-stage sleeve 16 advance as a whole. When the limiting column 32 on the seventh-stage sleeve 17 blocks the advance of the sixth-stage sleeve 16, the limiting ball 21 on the sixth-stage sleeve 16 is automatically pushed into the first limiting groove 22 of the outer layer of the sixth-stage sleeve 16 (i.e. the seventh-stage sleeve 17), at this time the fifth-stage sleeve 15 is unlocked, so that the fifth-stage sleeve 15 and the sixth-stage sleeve 16 slide relative to each other, and the first-stage sleeve 11 to the fifth-stage sleeve 15 advance as a whole again, until the limiting column 32 on the sixth-stage sleeve 16 blocks the advance of the fifth-stage sleeve 15. In turn, until the first-stage sleeve 11 is blocked by the limiting column 32 of the second-stage sleeve 12, reaching the extended state. At this time, the limiting balls 21 on the second-stage sleeve 12 to the sixth-stage sleeve 16 are fixed relative to each other between the adjacent outer layers, and the first-stage sleeve 11 can move leftward to compress the spring inside the second-stage sleeve 12, for retraction after reaching the surgical site.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0047] Alternatively, specific examples in the embodiments can refer to the examples described in the above embodiments, and the embodiments will not be described here again.

[0048] The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments.

[0049] In the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0050] The above-mentioned only is the preferred embodiment of the present application, it should be pointed out, for the ordinary skilled in the art, without departing from the principle of the present application, can make a number of improvements and refinements, these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A telescoping passageway dilating device, comprising: The utility model relates to a telescopic device, including: N sleeve (1), the N sleeve (1) are set in turn and are named as first level sleeve, second level sleeve……N level sleeve respectively, wherein, N level sleeve is located the outermost layer, first level sleeve is located the innermost layer, N is greater than or equal to 3; Limiting assembly (2), the limiting assembly (2) includes the limiting slot of setting on each sleeve and the limiting ball (21) of setting on the adjacent inner and outer layer sleeve and can freely rotate, limiting ball (21) can realize the step-by-step extension or retraction of adjacent sleeve under the cooperation of limiting slot under the action of external force; Control assembly (3), the control assembly (3) is set between part sleeve, for limiting the sliding range between part sleeve, guaranteeing N-1 sleeve step-by-step extension and retraction, to first level sleeve, make sleeve can step-by-step extend outward or retract inward under the cooperation of limiting assembly (2) and control assembly (3) and the action of external force.

2. The expandable access device of claim 1, wherein, The control assembly (3) includes control slot (31) and limiting column (32), the control slot (31) is set on first level sleeve to N-1 level sleeve respectively, the limiting column (32) is fixed on the inner wall of second level sleeve to N level sleeve respectively and is matched with corresponding control slot (31) on each level sleeve, each level sleeve moves and drives limiting column (32) to move in control slot (31), thereby limiting the sliding range of corresponding sleeve.

3. The expandable access device of claim 2, wherein, The limiting ball (21) is set through the side wall of second level sleeve to N-1 level sleeve, the limiting slot includes first limiting slot (22) and second limiting slot (23), the limiting ball (21) is matched with first limiting slot (22) on the adjacent outer layer sleeve, first limiting slot (22) is set on the inner wall of third level sleeve to N level sleeve, for limiting when sleeve extends outward;The limiting ball (21) is matched with second limiting slot (23) on the adjacent inner layer sleeve, and second limiting slot (23) is set on the outer wall of first level sleeve to N-2 level sleeve, for limiting when sleeve retracts inward.

4. The expandable access device of claim 3, wherein, The first limiting slot (22) is a curved groove, so that the limiting ball (21) can smoothly enter the second limiting slot (23) after being extruded by the adjacent outer layer sleeve when the sleeve retracts;The inner wall of the second limiting slot (23) is a plane, for preventing the sleeve from sliding due to external interference.

5. The expandable corridor dilation device of claim 1, wherein, The side wall of each sleeve is symmetrically provided with two limiting balls (21) on opposite sides thereof.

6. The expandable access device of claim 5, wherein, The limiting balls (21) on all sleeves are in the same plane, thereby ensuring uniform stress on the limiting assembly (2).

7. The expandable corridor dilation device of claim 2, wherein, Each sleeve is provided with a control slot (31) on opposite sides thereof, and the control slots (31) on opposite sides are located in the same plane;The planes in which the control slots (31) of adjacent sleeves are located are perpendicular to each other, thereby causing the control slots (31) of adjacent sleeves to be distributed in a staggered manner to avoid interference when multiple sleeves move.

8. The expandable access-staging device of any of claims 1-7, wherein, Further comprising a first spring (6), one end of which is fixed inside the N sleeves (1), and the other end is connected with the first level sleeve, for pushing the sleeves to extend outwards step by step under the elastic force.

9. The expandable access-staging device of any of claims 1-7, wherein, Further comprising an unlocking assembly (4), which comprises an unlocking rod (41) capable of passing through the Nth sleeve, a second spring (42) sleeved on the unlocking rod (41), and a fixing hole (43) provided on the N-1th sleeve, the second spring (42) is used for pushing the unlocking rod (41) to move when the N-1th sleeve is retracted, and when the N-1th sleeve is retracted to a specified position, the unlocking rod (41) automatically pops into the fixing hole (43); when the unlocking rod (41) is inserted into the fixing hole (43), the sleeves (1) are limited in the retracted state; when the unlocking rod (41) leaves the fixing hole (43), the N-1th sleeve is released, so that the sleeves extend out step by step under the external force.

10. The expandable access-staging device of any of claims 1-7, wherein, Further comprising a retaining sleeve (5), which is detachably sleeved on the outer wall of the Nth sleeve; when the first level sleeve reaches the operation position, the sleeves are retracted in turn by pressing the first level sleeve, and then the first level sleeve is pulled out, so that the retaining sleeve (5) is retained in the operation site, providing an operation channel for the operation.

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