CN221691232U - Minimally invasive adjustable growth rod and spine internal fixation system - Google Patents

Abstract

The utility model discloses a minimally invasive adjustable growth rod and spinal internal fixation system, belonging to the technical field of orthopedic implants, wherein the minimally invasive adjustable growth rod comprises a tubular shell, wherein: a fixing rod is fixedly arranged at one end of the shell, an axially fixed and circumferentially rotatable hollow sleeve is arranged in the shell, an extension rod threadedly connected to the hollow sleeve is arranged at the other end of the shell; a transmission device for driving the hollow sleeve to rotate is arranged inside the end of the shell close to the fixing rod, and a transmission interface for engaging with a transmission tool to drive the transmission device to work is arranged on the shell. The utility model can realize precise quantitative adjustment and simplify the adjustment operation steps; the planar thrust bearing can avoid the problem of transmission device jamming, greatly reduce the risk of structural wear or failure, increase the smoothness of adjustment, and is easy to use, thereby improving the efficiency of surgery.

Description

Minimally invasive adjustable growth rod and spinal fixation system

Technical Field

The utility model relates to the technical field of orthopedic implants, in particular to a minimally invasive adjustable growth rod and a spinal internal fixation system.

Background Art

The growing rod technique is used for non-fusion correction of scoliosis, generally for younger patients or adolescents, to maintain the balance of the coronal and sagittal planes of the spine while retaining the growth potential of the spine, and allowing the thorax to continue to grow, improving the thoracic volume and cardiopulmonary function. The common growing rod system is usually a four-pin four-rod structure, consisting of two sets of pedicle screw-rod systems, each set of screw-rod systems contains two staggered fixed rods, and the two rods are usually fixed by a cross-link with a fixing nut. Each adjustment and extension must be completed by unlocking and locking the fixing nut on the cross-link.

This technology usually requires repeated open surgeries to manually adjust the extension state of the growing rod to adapt to the normal growth of the child's spine. In each open surgery, the surgeon needs to manually unlock the fixing nut of the growing rod and adjust the relative position of the rod and lock it again. Accurate quantitative adjustment cannot be achieved. The fixing nuts of the growing rod and the cross-link rod will increase metal wear and affect the fixation strength during the repeated unlocking and locking process, which greatly increases the risk of surgical complications. Other growth rods may require frequent medical imaging to complete treatment, which increases radiation risks.

In recent years, various styles of growth rods have appeared, such as invention patent CN106963466B discloses a ratchet-shaped automatic growth valve, utility model patent CN208958295U discloses a growth rod used for spinal correction, and utility model patent CN212415869U discloses a growth rod. However, these growth rods still have the above-mentioned defects to a greater or lesser extent, which is a deficiency of the prior art and needs to be improved.

Utility Model Content

The technical problem to be solved by the utility model is to provide a minimally invasive adjustable growth rod and spinal internal fixation system which can realize accurate quantitative adjustment and is easy to use.

In order to solve the above technical problems, the utility model provides the following technical solutions:

In one aspect, a minimally invasive adjustable growing rod is provided, comprising a tubular housing, wherein:

A fixing rod is fixedly arranged at one end of the shell, a hollow sleeve which is axially fixed and circumferentially rotatable is arranged inside the shell, and an extension rod which is threadedly connected to the hollow sleeve is arranged at the other end of the shell;

A transmission device for driving the hollow sleeve to rotate is disposed inside one end of the housing close to the fixing rod, and a transmission interface for engaging with a transmission tool to drive the transmission device to work is disposed on the housing;

The transmission device adopts a bevel gear set to drive and connect the hollow sleeve, and the bevel gear set includes a bevel transmission gear and a transmission output gear that mesh with each other, and a locking gear for preventing the transmission device from retreating. An elastic member for pushing the locking gear to move upward to mesh with the transmission output gear is provided between the bottom of the locking gear and the side wall of the shell, and a planar thrust bearing is provided between the elastic member and the side wall of the shell.

Furthermore, the axis of the bevel transmission gear is perpendicular to the length direction of the housing, and the transmission interface is provided on the bevel transmission gear;

The axis of the transmission output gear is parallel to the length direction of the housing, and the transmission output gear is fixedly arranged at one end of the hollow sleeve close to the fixing rod.

Furthermore, the locking gear and the bevel transmission gear are coaxially and oppositely arranged, and the opposite end surfaces of the two gears are provided with a one-way ratchet structure that protrudes toward the opposite side and can mesh;

The locking gear and the bevel transmission gear respectively mesh with the upper and lower sides of the transmission output gear.

Furthermore, the bevel transmission gear can be moved up and down in the housing and always remains engaged with the transmission output gear during the up and down movement. When the bevel transmission gear moves downward, it pushes the locking gear downward to disengage the locking gear from the transmission output gear.

Furthermore, the planar thrust bearing is an annular planar thrust bearing system, which consists of three parts: upper, middle and lower. The upper ring and the lower ring are symmetrical rings, and the middle part is a ring-arranged ball structure. The balls are supported and fixed by a hollow ring with holes. The contact interfaces between the upper and lower rings and the balls are both provided with annular grooves to adapt to the ball structure and rolling path.

Furthermore, an anti-rotation sleeve is provided inside one end of the housing away from the fixing rod and is sleeved on the extension rod to prevent the extension rod from falling out.

Furthermore, a first limiting boss is provided inside one end of the housing away from the fixing rod, and a second limiting boss matching the first limiting boss is provided at the inner end of the anti-rotation sleeve;

And/or, the extension rod is provided with an anti-rotation wing extending along the length direction, and the inner side of the anti-rotation sleeve is provided with an anti-rotation groove matching with the anti-rotation wing;

And/or, the extension rod includes a large diameter section close to the fixing rod and threadedly connected to the hollow sleeve, and a small diameter section away from the fixing rod and matched with the anti-rotation sleeve.

Furthermore, the hollow sleeve is provided with an annular limiting groove, the outer shell is provided with a limiting pin, and the end of the limiting pin extends into the annular limiting groove.

Furthermore, the distal end of the fixing rod is in a blunt-tipped shape;

And/or, the hollow sleeve is made of biocompatible metal or PEEK;

And/or, a gear bushing is provided on the locking gear, and the gear bushing is made of PEEK.

On the other hand, a spinal internal fixation system is provided, comprising a pedicle screw and the above-mentioned minimally invasive adjustable growing rod.

The utility model has the following beneficial effects:

The utility model discloses a minimally invasive adjustable growth rod and spinal internal fixation system, comprising a tubular outer shell, a fixing rod being fixedly arranged at one end of the outer shell, an axially fixed and circumferentially rotatable hollow sleeve being arranged inside the outer shell, and an extension rod being threadedly connected to the hollow sleeve being arranged at the other end of the outer shell; a transmission device for driving the hollow sleeve to rotate is arranged inside the end of the outer shell close to the fixing rod, and a transmission interface for engaging with a transmission tool to drive the transmission device to work is arranged on the outer shell, so that the extension rod can be precisely adjusted to be elongated or shortened by percutaneously inserting the transmission tool into the transmission interface and driving the transmission device to work, thereby achieving precise quantitative adjustment and simplifying the adjustment operation steps; the anti-friction structure (i.e., the plane thrust bearing) can avoid the problem of the transmission device being stuck, greatly reducing the risk of structural wear or failure, increasing the smoothness of adjustment, being easy to use, and improving the operation efficiency; and the utility model discloses a minimally invasive adjustable growth rod and spinal internal fixation system for use in minimally invasive surgery, thereby avoiding or reducing the possibility of complications caused by open surgery and reducing the pain of patients caused by repeated open surgery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a minimally invasive adjustable growth rod of the present invention, wherein (a) is an overall structural diagram, and (b) is a cross-sectional structural diagram of (a) along the A-A line;

FIG2 is a schematic diagram of the minimally invasive adjustable growth rod shown in FIG1 in use;

FIG3 is a schematic cross-sectional view of the transmission device in FIG1 ;

FIG. 4 is a schematic diagram of the cross-sectional structure of the anti-rotation sleeve in FIG. 1 .

DETAILED DESCRIPTION

In order to make the technical problems to be solved, technical solutions and advantages of the present invention more clear, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

In one aspect, the present invention provides a minimally invasive adjustable growth rod 110, 120, as shown in FIGS. 1-4, comprising a tubular housing 116, 126, wherein:

A fixing rod 113 is fixedly disposed at one end of the outer shell 116, 126, an axially fixed and circumferentially rotatable hollow sleeve 1261 is disposed inside the outer shell 116, 126, and an extension rod 117 threadedly connected to the hollow sleeve 1261 is disposed at the other end of the outer shell 116, 126 (that is, an internal thread is disposed inside the hollow sleeve 1261, and an external thread matching the internal thread is disposed at the end of the extension rod 117 (both are not shown));

A transmission device 114 for driving the hollow sleeve 1261 to rotate is disposed inside one end of the housing 116 , 126 close to the fixing rod 113 , and a transmission interface 115 , 125 for engaging with a transmission tool to drive the transmission device 114 to work is disposed on the housing 116 .

During the treatment process, when the minimally invasive adjustable growth rod of the utility model needs to be adjusted according to the patient's spinal growth condition, the operator can manually adjust the growth length of the growth rod through the minimally invasive incision, and the adjusted length is precise and controllable. Specifically, first, the transmission tool is percutaneously inserted into the transmission interface 115, 125, and then the transmission tool is used to drive the transmission device 114 to work. At this time, the transmission device 114 drives the hollow sleeve 1261 to rotate, and the extension rods 117, 127 threadedly connected to the hollow sleeve 1261 are extended or shortened under the rotation of the hollow sleeve 1261. When the appropriate length is reached, the rotation can be stopped.

In specific applications, the minimally invasive adjustable growth rod combination of the utility model can be used to form an adjustable growth rod system, and the adjustable growth rod system is introduced in detail below.

As shown in FIG2 , the adjustable growing rod system has a double growing rod 110, 120 structure, which is fixed on both sides of one or more curvatures of the spine 10 by pedicle screws 111, 112, 118, 119, 121, 122, 128, 129. Then the transmission interface 115, 125 is rotated by a transmission tool to extend the growing rod 110, 120, and the patient's spine is extended by minimally invasive surgery every six months. Each growing rod (assembly) 110, 120 consists of three main parts. The first part is an extension rod 117, 127, the rod is mechanically connected to the housing 116, 126, the rod head is in the housing 116, 126/hollow sleeve 1261, and the tail is locked with the pedicle screws 118, 119. The housing 116, 126 is mechanically connected to the third part of the fixing rod 113, 123, and the fixing rod 113 is locked with the pedicle screws 111, 112. The housing 116, 126 includes a rotatable transmission interface 115, 125, which can be engaged with a transmission tool to extend or shorten each growth rod 110, 120 assembly. The transmission interface can be any commonly used interface form, such as an internal hexagonal interface, an internal hexagonal plum interface, etc.; the matching transmission tool can be a common instrument such as a straight rod, a T-shaped or L-shaped ordinary or ratchet wrench. The growth rod assembly can be fixed to the spine through a pedicle screw. The growth rod assembly can be implanted forward or reverse (i.e., the fixing rod 113 is at the proximal end, or the fixing rod 113 is at the distal end), usually used in pairs, and placed on the posterior side of the spinal vertebral body in the form of bilateral pedicle screw rods. It can also be used alone in specific circumstances. The length of the growth rod assembly can be flexibly set as needed, for example, the length is 660 mm when fully extended, and 600 mm when fully retracted, allowing an extension length of 60 mm.

The minimally invasive adjustable growth rod of the utility model comprises a tubular shell, one end of which is fixed with a fixing rod, an axially fixed and circumferentially rotatable hollow sleeve is arranged inside the shell, and an extension rod threadedly connected to the hollow sleeve is arranged at the other end of the shell; a transmission device for driving the hollow sleeve to rotate is arranged inside the end of the shell close to the fixing rod, and a transmission interface for engaging with a transmission tool to drive the transmission device to work is arranged on the shell, so that the extension rod can be precisely adjusted to be elongated or shortened by percutaneously inserting the transmission tool into the transmission interface and driving the transmission device to work, thereby achieving precise quantitative adjustment and simplifying the adjustment surgical steps; the minimally invasive adjustable growth rod of the utility model is used for minimally invasive surgery, thereby avoiding or reducing the possibility of complications caused by open surgery, reducing the pain of patients caused by repeated open surgery, and the treatment can be completed without the aid of medical imaging during the operation, and the radiation risk is low.

The transmission device 114 can adopt various structural forms that can be easily thought of by those skilled in the art. For the convenience of implementation, the following structural forms are preferably adopted:

As shown in FIG. 1-3 , the transmission device 114 uses a bevel gear set 1151 to drive and connect the hollow sleeve 1261 . The bevel gear set 1151 includes a bevel transmission gear 1501 and a transmission output gear 1507 that mesh with each other, wherein:

The axis of the bevel transmission gear 1501 is perpendicular to the length direction of the housing 116, 126, and the bevel transmission gear 1501 is provided with transmission interfaces 115, 125;

The axis of the transmission output gear 1507 is parallel to the length direction of the housings 116 and 126 , and the transmission output gear 1507 is fixed to one end of the hollow sleeve 1261 close to the fixing rod 113 .

That is, the transmission device 114 may firstly include two parts: a bevel transmission gear 1501 and a transmission output gear 1507, wherein the bevel transmission gear 1501 is connected to the transmission interface 115 and is responsible for input transmission; and the transmission output gear 1507 is connected to the hollow sleeve 1261 and is responsible for transmission output. In specific implementation, the bevel transmission gear teeth 1503 mesh with the transmission output gear teeth 1508, and when the bevel transmission gear 1501 rotates, the transmission output gear 1507 and the hollow sleeve 1261 rotate accordingly, and the extension rod 117 moves longitudinally relative to the transmission device 114.

To prevent the transmission device 114 from falling back, the bevel gear set 1151 may further include a locking gear 1502 for preventing the transmission device 114 from falling back, wherein:

The locking gear 1502 and the bevel transmission gear 1501 are coaxial and arranged opposite to each other, and the opposite end surfaces of the two gears are provided with one-way ratchet structures 1506 and 1505 that protrude toward the opposite sides and can mesh;

The locking gear 1502 and the bevel transmission gear 1501 engage the upper and lower sides of the transmission output gear 1507 respectively.

Furthermore, an elastic member (specifically, a wave spring 1510 ) may be provided between the bottom of the locking gear 1502 and the side walls of the housing 116 , 126 for pushing the locking gear 1502 to move upward to engage with the transmission output gear 1507 .

The bevel transmission gear 1501 is preferably movable up and down (along its axial direction) and is arranged in the housing 116 and always remains engaged with the transmission output gear 1507 during the up and down movement. When the bevel transmission gear 1501 moves downward, it pushes the locking gear 1502 to move downward so that the locking gear 1502 is disengaged from the transmission output gear 1507.

That is to say, the transmission device 114 may also include a third part: a locking gear 1502, wherein the bevel transmission gear 1501 and the locking gear 1502 are coaxial and are provided with one-way ratchet structures 1505 and 1506 protruding upward, and the two ratchets can mesh. A wave spring 1510 is provided below the locking gear 1502, which can force the locking gear 1502 to move upward, so that the locking gear teeth 1504 mesh with the transmission output gear teeth 1508, while keeping the ratchet teeth 1506 of the locking gear 1502 meshed with the ratchet teeth 1505 of the bevel transmission gear 1501. The structures 1505 and 1506 are one-way ratchets, and the tooth shape can be a right-angled triangular prism shape, the inclined surface is a guide surface, the right-angle surface is a check surface, and the protruding intersecting edges on both sides are tooth tips. Cooperating with the wave spring 1510 at the bottom of the locking gear 1502, this structure can realize that when the transmission gear 1501 is only rotated in the horizontal direction under force, the conical transmission gear 1501 and the locking gear 1502 can only maintain a single direction of relative movement, that is, the tooth tip moves from bottom to top along the opposite ratchet guide inclined surface. When the tooth tip on one side moves to the top of each guide surface (i.e. the tooth tip on the opposite side), the tooth tip on this side crosses the tooth tip on the opposite side under the compression of the wave spring 1510 and contacts the next guide surface to continue moving. When the gears on both sides have a tendency to move in the opposite direction relative to each other, the right-angled check surfaces of the ratchet teeth on both sides contact and close to limit the reverse movement, thereby achieving the effect of preventing the transmission device 114 from retreating.

After the extension rod 117 is passively extended, the locking gear 1502 is responsible for locking the bevel transmission gear 1501 and the transmission output gear 1507. The operator inserts the external transmission tool into the transmission interface 115 and applies downward force to compress the wave spring 1510 to the maximum position, so that the locking gear 1502 sinks to the lowest position, and the locking gear teeth 1504 are disengaged from the transmission output gear teeth 1508, that is, the locking gear 1502 loses the ability to lock the transmission output gear 1507, and then loses the ability to lock the bevel transmission gear 1501. At this time, the ratchet 1506 of the locking gear 1502 and the ratchet 1505 of the bevel transmission gear 1501 remain in meshing, and the operator can adjust the length of the extension rod 117 at will, that is, extend or shorten it. After the adjustment is completed, the operator withdraws the applied force, and the wave spring 1510 pushes the locking gear 1502 back to the initial position. At this time, the locking gear teeth 1504 re-engage with the transmission output gear teeth 1508, and the locking gear 1502 resumes the ability to lock the transmission output gear 1507 and the bevel transmission gear 1501.

A planar thrust bearing 101 may be provided between the elastic member (i.e., the wave spring 1510) and the side wall of the outer shell 116 to prevent excessive friction at the interface when the transmission device 114 is subjected to a downward pull, resulting in jamming or wear of the activity and causing failure of the adjustment transmission function. That is, the anti-friction structure (i.e., the planar thrust bearing) can avoid the problem of jamming of the transmission device, greatly reduce the risk of structural wear and failure, increase the smoothness of adjustment, facilitate use, and improve surgical efficiency.

The plane thrust bearing 101 can be specifically an annular plane thrust bearing system, which consists of three parts: upper, middle and lower. The upper and lower rings are symmetrical rings, and the middle part is a ring-arranged ball structure. The balls are supported and fixed by a hollow ring with holes; the contact interfaces between the upper and lower rings and the balls are both provided with annular grooves, which are adapted to the ball structure and rolling path. When the gears in the transmission device 114 rotate, the upper ring of the bearing rotates with the locking gear 1502 and the wave spring 1510, the lower ring and the housing 116 are relatively stationary, and the balls in the middle ring roll with the relative rotation of the upper and lower rings, converting the original sliding friction between the interfaces into rolling friction, greatly reducing the wear and jamming problems of the transmission device, and improving the smoothness of gear adjustment and surgical efficiency.

As shown in Figures 1 and 4, an anti-rotation sleeve 1262 may be provided inside the end of the shell 116 away from the fixed rod 113 and sleeved on the extension rod 117 to prevent the extension rod 117 from falling out, thereby preventing the extension rod 117 from falling out of the end of the shell 116 when the growth rod reaches the longest extension length.

To prevent the anti-rotation sleeve 1262 from falling out, a first limiting boss 1166 may be provided inside the end of the housing 116 away from the fixed rod 113, and a second limiting boss 1267 cooperating with the first limiting boss is provided at the inner end of the anti-rotation sleeve 1262. In addition, an anti-rotation wing 1171 extending along the length direction may be provided on the extension rod 117, and an anti-rotation groove 1265 cooperating with the anti-rotation wing 1171 is provided on the inner side of the anti-rotation sleeve 1262 to prevent the anti-rotation sleeve 1262 and the extension rod 117 from rotating relative to each other. In addition, the extension rod 117 may include a large diameter section 1172 that is close to the fixed rod 113 and threadedly connected to the hollow sleeve 1261, and a small diameter section 1173 that is away from the fixed rod 113 and cooperates with the anti-rotation sleeve 1262. In this way, the small diameter section 1173 can move in the anti-rotation sleeve 1262, and the large diameter section 1172 cannot pass through the anti-rotation sleeve 1262, thereby facilitating the anti-escape prevention of the extension rod 117.

In order to facilitate the axial fixation and circumferential rotation of the hollow sleeve 1261 in the outer shell 116, various methods that can be easily thought of by technical personnel in this field can be adopted. For the convenience of implementation, preferably, an annular limit groove 1263 can be provided on the hollow sleeve 1261, and a limit pin 1264 is provided on the outer shell 116. The end of the limit pin 1264 extends into the annular limit groove 1263, thereby preventing the hollow sleeve 1261 from shifting.

The distal end of the fixing rod 113 may be blunt-tipped, which facilitates passing through soft tissue during implantation and avoids secondary injury. The hollow sleeve 1261 may be made of biocompatible metal or PEEK to reduce wear debris. The locking gear 1502 may be provided with a gear bushing 1509, which may be made of PEEK to reduce wear debris.

On the other hand, the utility model provides a spinal internal fixation system, including pedicle screws and the above-mentioned minimally invasive adjustable growing rod. Since the structure of the minimally invasive adjustable growing rod is the same as above, it will not be described here in detail.

The utility model provides a spinal internal fixation system, including a pedicle screw and a minimally invasive adjustable growth rod, wherein the growth rod includes a tubular shell, a fixing rod is fixedly arranged at one end of the shell, an axially fixed and circumferentially rotatable hollow sleeve is arranged in the shell, and an extension rod threadedly connected to the hollow sleeve is arranged at the other end of the shell; a transmission device for driving the hollow sleeve to rotate is arranged inside the end of the shell close to the fixing rod, and a transmission interface for engaging with a transmission tool to drive the transmission device to work is arranged on the shell, so that the extension rod can be accurately adjusted to be elongated or shortened by percutaneously inserting the transmission tool into the transmission interface and driving the transmission device to work, thereby achieving precise quantitative adjustment and simplifying the adjustment operation steps; the anti-friction structure (i.e., the plane thrust bearing) can avoid the problem of transmission device jamming, greatly reduce the risk of structural wear or failure, increase the smoothness of adjustment, be easy to use, and improve the operation efficiency; and the utility model provides a spinal internal fixation system for minimally invasive surgery, thereby avoiding or reducing the possibility of complications caused by open surgery and reducing the pain of patients caused by repeated open surgery.

The utility model provides a spinal internal fixation system that changes the traditional four-pin four-rod growing rod into a four-pin two-rod form, wherein two extendable rods are respectively located on both sides of the spine, and each rod body comprises an outer shell, a fixing rod extending along the longitudinal vertical axis, and an extension rod extending along the longitudinal vertical axis.

The operation steps of the spinal internal fixation system of the present invention can be referred to as follows:

1. Anesthesia, incision, pedicle screws are inserted into the head and caudal vertebrae of the orthopedic segment according to the pedicle screw rod implantation method, and the head and caudal screws are connected with an extendable growth rod. At this time, the growth rod transmission device is in the initial position, and the first operation is completed;

2. According to the patient's spinal growth and surgical cycle, when the length of the growth rod needs to be adjusted, cooperate with preoperative imaging positioning, make a minimally invasive incision at the transmission interface, clean the subcutaneous soft tissue in the field of view, and use the transmission tool to adjust the growth rod as needed. After adjustment, the internal transmission device will automatically lock without additional operation, and the subsequent surgery can be completed according to the routine process.

In summary, the minimally invasive adjustable growth rod and spinal internal fixation system of the present invention also have the following advantages:

1. It is a minimally invasive growth rod system, including a fixing rod, an extension rod, a transmission device, a transmission gear set, etc. It can adjust the length of the growth rod through minimally invasive surgery, avoid or reduce the possibility of complications caused by open surgery, and reduce the pain of patients caused by repeated open surgery;

2. The minimally invasive growth rod of the utility model is designed with a locking device to prevent the extension rod from retracting after the operator adjusts the length of the growth rod, or the transmission gear set from causing the extension rod to retract under the pressure of the spine;

3. The anti-friction structure (i.e., plane thrust bearing) avoids the problem of transmission device jamming, greatly reduces the risk of structural wear and failure, increases the smoothness of adjustment, and improves the surgical effect.

The above is a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.

Claims (10)

1. A minimally invasive adjustable growth rod comprising a tubular housing, wherein:

One end of the shell is fixedly provided with a fixed rod, a hollow sleeve which is axially fixed and circumferentially rotatable is arranged in the shell, and the other end of the shell is provided with an extension rod which is in threaded connection with the hollow sleeve;

A transmission device for driving the hollow sleeve to rotate is arranged in one end, close to the fixed rod, of the shell, and a transmission interface for being engaged with a transmission tool to drive the transmission device to work is arranged on the shell;

The transmission device is in driving connection with the hollow sleeve by adopting a bevel gear set, the bevel gear set comprises a bevel transmission gear and a transmission output gear which are meshed with each other, and a locking gear used for preventing the transmission device from retreating, an elastic piece used for pushing the locking gear to move upwards to be meshed with the transmission output gear is arranged between the lower part of the locking gear and the side wall of the shell, and a plane thrust bearing is arranged between the elastic piece and the side wall of the shell.

2. The minimally invasive adjustable growth bar of claim 1, wherein the axis of the bevel drive gear is perpendicular to the length direction of the housing, the bevel drive gear having the drive interface thereon;

The axis of the transmission output gear is parallel to the length direction of the shell, and the transmission output gear is fixedly arranged at one end of the hollow sleeve close to the fixed rod.

3. The minimally invasive adjustable growth bar according to claim 1, wherein the locking gear and the bevel gear are coaxially and oppositely arranged, and opposite end surfaces of the locking gear and the bevel gear are provided with opposite-side protruding and engageable one-way ratchet structures;

The locking gear and the bevel drive gear engage the upper and lower sides of the drive output gear, respectively.

4. A minimally invasive adjustable growth bar according to claim 3, wherein the bevel drive gear is movably disposed within the housing and is always in engagement with the drive output gear during the up and down movement, and when the bevel drive gear moves downward, the locking gear is urged to move downward to disengage the locking gear from the drive output gear.

5. The minimally invasive adjustable growth bar of claim 1, wherein the planar thrust bearing is an annular planar thrust bearing system comprising an upper ring and a lower ring, the upper ring and the lower ring being symmetrical rings, the middle portion being an annular arrangement of balls supported and secured by a hollowed out band Kong Yuanhuan, the upper ring and the lower ring having annular grooves at their contact interfaces, the ball structures and rolling paths being adapted.

6. The minimally invasive adjustable growth bar of any one of claims 1-5, wherein an anti-rotation sleeve is provided inside an end of the housing remote from the fixation bar that fits over the extension bar to prevent the extension bar from backing out.

7. The minimally invasive adjustable growth bar of claim 6, wherein a first limit boss is provided inside an end of the housing remote from the fixed bar, and a second limit boss is provided inside the inner end of the anti-rotation sleeve and is matched with the first limit boss;

And/or the extension rod is provided with an anti-rotation wing extending along the length direction, and the inner side of the anti-rotation shaft sleeve is provided with an anti-rotation groove matched with the anti-rotation wing;

And/or the extension rod comprises a large-diameter section which is close to the fixing rod and is in threaded connection with the hollow sleeve, and a small-diameter section which is far away from the fixing rod and is matched with the anti-rotation shaft sleeve.

8. The minimally invasive adjustable growth bar of claim 6, wherein the hollow sleeve is provided with an annular limiting groove, the housing is provided with a limiting pin, and the end of the limiting pin extends into the annular limiting groove.

9. The minimally invasive adjustable growth bar of claim 3, wherein the distal end of the fixation bar is blunt pointed;

And/or the hollow sleeve is made of biocompatible metal or PEEK;

And/or the locking gear is provided with a gear bushing, and the gear bushing is made of PEEK.

10. An intraspinal fixation system comprising pedicle screws and a minimally invasive adjustable growth rod as claimed in any one of claims 1-9.