CN1631326A - Expanded Intramedullary Nail - Google Patents

Abstract

The invention discloses an opening type intramedullary nail which comprises a nail member and a center-pole, wherein the nail member is in hollow pipe shape and includes a far-end and a near-end, the nail member is provided with a pinning aperture equipped with a pin, the center-pole includes a far end and a near end, the center-pole is arranged in the hollow pipe of the nail member in a movable manner, the pipe wall of the nail member far-end is provided with expansion slots longitudinally, the far end of the center-pole is provided with an expansion head, the maximum outside diameter of the expansion head is larger than the internal diameter of the pipeline section where the expansion slot is located, the near end of the center-pole is located at the near-end of the nail member, and the expansion head is connected with the center-pole to form a union body for synchronous rotation and moving, the near head section of the center-pole is equipped with a screw-threaded axial draught device.

Description

Expanded Intramedullary Nail

【Technical field】

The present invention relates to orthopedic instruments, more specifically, the present invention relates to an intramedullary nail for treating fractures.

【Background technique】

In the treatment of limb fractures, especially in the treatment of leg fractures, improper treatment is prone to sequelae such as delayed union, nonunion, or malunion of the fracture, which affects the therapeutic effect. In recent years, more advanced intramedullary nailing technology and equipment have been used in the treatment of femur and other limb fractures. Intramedullary nailing belongs to the internal fixation technology of fractures. Forming a whole, it can control the rotation and shear force of the fracture end to a certain extent, and prevent the rotation and displacement of the fracture site, thus expanding the indications of the intramedullary nail to comminuted, long oblique, and fractures at both ends of the femur. The stability of fixation improves the fracture healing rate, reduces the infection rate, and adds a more biological approach to the treatment of fractures. However, in practice, it is found that there are still the following defects: 1) because the locking nail is located at both ends of the long bone, the surgical incision must be increased, the operation of installing the locking nail is cumbersome, and the side damage is large; The distance between the left and right swing of the inner nail and the main positioning rod changes, so that the height gauge cannot be positioned accurately, resulting in the locking hole of the intramedullary nail and the positioning hole on the main positioning rod are not on the same plane, which often leads to drilling failure, requiring CT or CT again. Drilling holes under X-ray not only prolongs the operation time, increases the difficulty of the operation, but also affects the effect of the operation; 3) The intramedullary nail and the corresponding locking nail have no pressurizing effect on the fracture line, and the fracture may still loosen or even stagger after fixation, thus Increase the fracture gap, which is not conducive to fracture healing; 4) After the intramedullary nail and the corresponding locking nail are fixed, a static fixation is formed, resulting in stress concentration on the intramedullary nail and the corresponding locking nail, resulting in the intramedullary nail and/or the corresponding locking nail. The locking nail is broken; 5) and the static fixation, due to the relationship between the elastic modulus, produces stress shielding on the fracture site, resulting in fracture nonunion.

In order to solve the above problems, Chinese patent document 200320107607.7 discloses a fixed self-locking composite interlocking intramedullary nail between the trochanters of the femur. The nail consists of two parts. Among them, the femoral neck self-locking intramedullary nail involves two parts: the main body of the femoral neck self-locking intramedullary nail, the femoral neck self-locking core nail, and a positioning screw. And its femoral shaft self-locking intramedullary nail consists of the main body of the femoral shaft self-locking intramedullary nail, the expansion lock core and the fastening screw. The fracture lines are intercalated and closely aligned, which can fix the intertrochanteric fracture, effectively prevent any form of rotation and displacement, and facilitate fracture healing; the surgical trauma is small, the operation is easy, and the relative cost is relatively low. Good for early exercise. However, although the femoral neck self-locking core nail and the femoral shaft expansion lock core have bifurcations that prevent the two sections of the fracture from rotating with each other, due to the characteristics of the expansion structure of the nail, the processing is complicated, the strength is difficult to guarantee, and the expansion and anti-rotation force is difficult. Guarantee; and more importantly, the axis of the inner cavity of the bone is curved, and the intramedullary nail cannot be too thin because of its strength. The tension screw and expansion lock core in the inner nail will be bent to different degrees or blocked by the inner wall of the intramedullary nail. During the implantation of the intramedullary nail, it is difficult to pull the screw head at the other end. The nut-type expansion head at the other end is also difficult to advance the expansion lock cylinder rod by dividing the screw head at the other end to make the bifurcations widen, which will bring difficulties to the implantation operation and even lead to the failure of the operation; even if the implantation Successfully, when the fracture is healed, when the locking nail needs to be removed, the expansion head or the expansion lock core rod may be difficult to loosen and release the expansion due to the force applied by the screw, the difficulty in advancing and retreating, the rotation and extraction, or the expansion of the nut after removal. The big head is completely detached from the distal end of the control screw and falls into the medullary cavity, which increases the difficulty of taking out the operation and the pain of the patient.

Similar to the above problem, there is a Chinese patent document 02207522.4 which discloses an expansion screw type self-locking intramedullary nail, which includes two parts: the main nail and the central stud. The proximal end of the main nail body is automatically opened to control the rotation of the proximal fracture, and the distal end is a locking nail device to control the rotation of the distal fracture; it is said that it can be used for internal fixation of lower femoral fractures, and the expansion screw type self-locking intramedullary Nail, the locking nail hole is changed to 135°, the intramedullary nail is reversed, and it can also be used for subtrochanteric fractures. It can overcome the disadvantages of cumbersome operation, multiple surgical incisions, complex supporting equipment, and static fixation of the locking nail positioning device with locking intramedullary nails. It has the function of elastic fixation, simple operation, relatively small damage, no need for special equipment, and low manufacturing cost. Low, suitable for widespread development. However, this device has similar disadvantages as above: there is also the large-headed conical nut and the central stud control head at two ends, because the tortuous medullary cavity causes difficulty in turning and advancing and retreating, which is not conducive to surgical implantation, nor is it conducive to taking out the lock after recovery. Nails, even lead to failure of the implantation operation or the complete detachment of the large-headed conical nut from the control center stud and fall into the medullary cavity, increasing the difficulty of taking out the operation and the pain of the patient.

Similar to the above technology, there is also Chinese patent document 01230173.6 which discloses an expansion screw type self-locking intramedullary nail, which includes two parts, the main nail and the central stud. The reformation, through the slotting of the distal part of the main nail body, and the upward movement of the tapered nut, the distal part of the main nail body is automatically opened to control the rotation of the distal part of the fracture, and the ratchet device at the proximal end controls the rotation of the proximal part of the fracture. It is said that the intramedullary nail is used for orthopedic treatment of femoral shaft fractures, which overcomes the shortcomings of cumbersome positioning device operation, multiple surgical incisions, complex supporting equipment, and static fixation. It needs special equipment, low manufacturing cost, and suitable for extensive development. In fact, the shortcoming of this device is similar to the above and will not be repeated here.

【Content of invention】

In view of the above-mentioned shortcomings of the prior art, the technical purpose of the present invention is to provide a device with easy surgical implantation and removal, simple structure, strong anti-rotation torque, no stress concentration and stress shielding, and a dynamic fixation feature. Expanded intramedullary nail.

For this reason, the technical solution of the present invention is a kind of expansion type intramedullary nail, and this expansion type intramedullary nail comprises nail body and central rod, and described nail body is hollow tubular and includes distal end and proximal end, and on the nail body A locking nail hole is provided and a locking nail is provided. The central rod includes a far head and a proximal head. The central rod is movably fitted in the hollow tube of the nail body; the tube wall at the far end of the nail body is longitudinally provided with an expansion groove, and the central rod The far head is provided with an expansion head, the maximum outer diameter of the expansion head is larger than the inner diameter of the pipe section where the expansion groove is located, the proximal head of the central rod is located at the proximal end of the nail body, and the expansion head and the central rod are connected to each other to form a A combination of synchronous rotation and movement, the proximal section of the central rod is provided with a threaded axial traction device. In the present invention, the expansion head is simply made into a coupling body that can rotate and move synchronously with the central rod, and a threaded axial traction device is arranged on the proximal section of the central rod, so that the expansion head can be completely avoided during implantation and removal during surgery. Falling from the central rod; furthermore, using the friction force between the expansion groove at the far end of the nail body and the expansion head and the retarding force of the central rod by the inner wall of the nail, the central rod is restricted from rotating, and due to the near head of the central rod In the short distance of the central rod, the straightness and thread rotation fit of the central rod can be guaranteed. The operator only needs to easily rotate the nut of the threaded axial traction device at the near head of the central rod with the help of a socket wrench. The expansion head at the distal end is pulled to move axially towards the proximal end by the non-rotating central rod, so as to tighten or loosen the expansion head at the distal end, so that the expansion groove at the distal end of the nail body is simply opened or loosened, so that the nail body The distal expansion groove can be strongly propped on the inner wall of the medullary cavity, effectively preventing the rotational displacement between the two segments of the fracture, which is conducive to both surgical implantation and surgical removal after recovery; moreover, during surgical implantation and surgical removal, As long as an operation port is opened at the proximal end, the axial traction device can be effectively controlled nearby, thus completely solving the disadvantages that the traditional expandable intramedullary nail is difficult to implant or take out. Compared with the traditional interlocking intramedullary nail, this The invented spread-type intramedullary nail locks at the proximal end and spreads the distal end, which can effectively control the rotation, but does not limit the axial micro-motion of the fracture end under pressure, so it is an axial dynamic fixation device that eliminates It eliminates the stress concentration of interlocking nails caused by static fixation, and also eliminates the stress shielding of fractures caused by traditional static fixation on interlocking nails. Therefore, it not only eliminates the occurrence of nail breakage accidents, but also prevents the occurrence of fracture nonunion. ills. Trials have proved that the intramedullary nail of the present invention has the advantages of easy surgical implantation and removal, simple structure, strong anti-rotation torque, and can greatly reduce the stress of the locking nail.

In order to further strengthen the above-mentioned basic advantages of the present invention, the present invention adopts the following more specific improvement measures: the expansion head and the central rod are seamlessly connected in one piece.

The number of the expansion grooves is 2-4, and a plurality of expansion grooves are distributed symmetrically in the circumferential direction on the tube wall at the distal end of the nail body and divide the tube wall at the distal end into a corresponding number of wall pieces.

In order to further limit the rotation of the central rod, anti-rotation ribs inserted into the expansion groove are formed on the expansion head. The anti-rotation ribs can be inserted into at least two expansion grooves in a symmetrical distribution.

In order to facilitate manufacturing and operation, the specific structure of the proximal end of the nail body and the proximal head of the central rod of the present invention is as follows: the threaded axial traction device includes a fastening nut and an outer shell formed on the proximal section of the central rod. The thread, the fastening nut and the external thread are mutually rotatable; the hollow tube at the proximal section of the nail body forms an operating space for accommodating the fastening nut and is provided with a step to prevent the fastening nut from moving inward.

In order to facilitate the use of a socket wrench, the fastening nut of the present invention is a cylinder with a slot or a cross groove on the end surface, and the fastening nut is rotatably fitted in the operating space at the proximal end of the nail body.

In order to further increase the anti-rotation moment of the expansion wall piece to the inner wall of the medulla, a longitudinal anti-rotation groove is arranged on the outer wall surface of the wall piece. The number of anti-rotation grooves on each wall piece is 2 to 4, and the depth of the anti-rotation grooves is .

In order to improve the operation and efficiency of surgical implantation and reduce the labor intensity of the operator, the central rod can be made slightly longer than required, so that it is convenient to first use the sleeve with internal thread to cover the external thread of the excessively long section of the central rod Screw in a few turns and then pull directly until it can't be pulled, then reverse the outer hexagon nut to break off the too long section of the center rod, and then use a socket wrench to rotate the flat or cross groove of the fastening nut to gradually tighten the expansion head Therefore, correspondingly, the proximal end of the central rod of the present invention is formed with an outer hexagonal nut, and a breaking groove is provided at an appropriate axial position of the proximal portion of the central rod.

For the convenience of operations, the operation is performed at the proximal end, and the surgical trauma is reduced. Two docking ports for operating the nail body are symmetrically provided on the end of the proximal end of the nail body; at the end.

In a word, the structural improvement of the present invention has the advantages of simple implementation, effective and low cost.

Below, the technical solution of the present invention will be further described in conjunction with specific embodiments and accompanying drawings.

【Description of drawings】

Fig. 1 is a three-dimensional schematic diagram of an exploded structure of an embodiment of the intramedullary nail of the present invention.

Fig. 2 is an enlarged perspective view of a part of the distal end of an embodiment of the intramedullary nail of the present invention.

Fig. 3 is a cross-sectional view of the assembled structure of the embodiment of the intramedullary nail of the present invention in a state ready for implantation.

Fig. 4 is a cross-sectional view of the combined structure of the embodiment of the intramedullary nail in the implanted tension state.

【Detailed ways】

Example 1

As shown in Figures 1 and 2: a spread-type intramedullary nail, the spread-type intramedullary nail includes a nail body 1 and a central rod 2, the nail body 1 is hollow tubular and includes a distal end 10' and a proximal end 10. The nail body 1 is provided with a locking nail hole 11 and equipped with a locking nail 3. The central rod 2 includes a far head 20' and a proximal head 20. The central rod 2 is movably fitted in the hollow tube of the nail body 1; the nail body 1 The tube wall at the distal end 10' is longitudinally provided with four expansion grooves 12, and the four expansion slots 12 are distributed symmetrically in the circumferential direction on the tube wall at the distal end of the nail body 1 and divides the tube wall at the distal end 10' into four walls piece. The far head 20' of the center rod 2 is provided with an expansion head 4, the maximum outer diameter of the expansion head 4 is greater than the inner diameter of the pipe section where the expansion groove 12 is located, the near head 20 of the center rod 2 is located at the proximal end 10 of the nail body 1, and The expansion head 4 is connected with the central rod 2 to form an integrated seamless joint that can rotate and move synchronously. The expansion head 4 is formed with two anti-rotation ribs 41 inserted into the expansion groove 12 . The proximal 20 sections of the central rod 2 are provided with threaded axial traction devices.

A longitudinal anti-rotation groove 15 is formed on the outer wall surface of the wall piece. The number of anti-rotation grooves 15 on each wall sheet is three, and the depth of the anti-rotation grooves 15 is .

3 and 4 at the same time: the threaded axial traction device includes an external thread 23 formed on the near head 20 section of the central rod 2 and a fastening nut 5 that is mutually rotatable with the external thread 23; The empty pipe forms an operating space for accommodating the fastening nut 5 and is provided with a step 13 for preventing the fastening nut 5 from moving inwardly. The fastening nut 5 is a cylinder with a cross groove 51 on the end surface, and the fastening nut is rotatably fitted in the operating space of the proximal end 10 of the nail body 1 .

An outer hexagonal nut 21 is formed at the end of the central rod 2 near the head 20 , and a breaking groove 22 is provided at an appropriate axial position of the central rod 2 near the head 20 .

Two docking ports 13 for operating the nail body 1 are symmetrically provided on the end of the proximal end 10 of the nail body 1 ; two locking nail holes 3 are opened at the proximal end 10 of the nail body 1 . The docking port 13 can be docked with other surgical instruments.

When the combination under the implanted tension state is completed, the outer hexagonal nut 21 can be reversed to break the central rod 2 from the breaking groove 22, and an auxiliary section from the breaking groove 22 to the outer hexagonal nut 21 is discarded, leaving Break off the groove 22 as the proximal head 20 of the central rod 2 in the implanted state, and continue to tighten the fastening nut 5 until the nail body 1 is completely expanded on the medullary cavity, and the operation is completed; The barrel wrench reverses and fastens the nut 5 to remove and take out the nail body 1 .

Claims (10)

1, a kind of opening type intramedullary nail, this opening type intramedullary nail comprises nail body (1) and center-pole (2), described nail body (1) is for hollow tubular and comprise far-end (10 ') and near-end (10), offer locking nail hole (11) on the described nail body (1) and be furnished with pinning (3), described center-pole (2) comprises head far away (20 ') and nearly head (20), and described center-pole (2) clearance fit is in the hollow pipe of nail body (1); Offer expansion slot (12) on the tube wall of described nail body (1) far-end (10 ') is vertical, the head far away (20 ') of described center-pole (2) is provided with expansion-head (4), the maximum outside diameter of described expansion-head (4) is greater than the internal diameter of described expansion slot (12) place pipeline section, the nearly head (20) of described center-pole (2) is positioned at the near-end (10) of described nail body (1), it is characterized in that: described expansion-head (4) is interconnected to form the union body that can rotate synchronously and move with described center-pole (2), and nearly head (20) section of described center-pole (2) is provided with screw-type axial traction device.

2, opening type intramedullary nail as claimed in claim 1 is characterized in that: be the integral type seamless link between described expansion-head (4) and described center-pole (2).

3, opening type intramedullary nail as claimed in claim 1, it is characterized in that: the number of described expansion slot (12) is 2～4, many expansion slots (12) described nail body (1) far-end tube wall last week to distributing symmetrically and the tube wall of far-end being partitioned into the wall sheet of respective number.

4, opening type intramedullary nail as claimed in claim 1 or 2 is characterized in that: be formed with the anti-muscle sheet (41) that revolves that inserts described expansion slot on the described expansion-head (4).

5, opening type intramedullary nail as claimed in claim 1 or 2 is characterized in that: described screw-type axial traction device is included in the external screw thread (23) of the nearly head section of described center-pole (2) formation and the fastening nut (5) that cooperates with the mutual rotation of this external screw thread (23); The nearly section of described nail body (1) hollow pipe forms the working place that holds described fastening nut (5) and is provided with and stops the step (13) that moves in this fastening nut (5).

6, opening type intramedullary nail as claimed in claim 5 is characterized in that: described fastening nut (5) has the cylinder of a word or cross recess (51) for end face, and described fastening nut (5) is rotatably assorted in the working place of described nail body (1) near-end (10).

7, opening type intramedullary nail as claimed in claim 3 is characterized in that: be formed with anti-rotation groove (15) longitudinally on the outside wall surface of described wall sheet.

8, opening type intramedullary nail as claimed in claim 7 is characterized in that: the number of the anti-rotation groove (15) on every wall sheet is 2～4.

9, opening type intramedullary nail as claimed in claim 1 or 2 is characterized in that: the nearly head of described center-pole (2) (20) end is formed with outer-hexagonal nut (21), and the suitable axial positions of the nearly head of center-pole (2) (20) section is provided with snap slot (22).

10, opening type intramedullary nail as claimed in claim 1 or 2 is characterized in that: go back the docking ports (14) that symmetry offers 2 described nail bodies of operation (1) on the termination of described nail body (1) near-end (10); Described locking nail hole (11) is opened in described nail body (1) near-end (10) and locates.

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