CN211610019U - Novel hollow compression screw with detachable head - Google Patents

Abstract

The utility model discloses a novel hollow forcing screw of detachable head belongs to orthopedic implant technical field, hollow forcing screw includes screwhead and screw rod portion, the central axial of screwhead and screw rod portion is run through and has been seted up the guiding hole, screwhead detachable installs screw rod portion, be provided with the packing ring of the back area dogtooth between screwhead and the screw rod portion. The utility model discloses it is effectual to pressurize, and the maneuverability scheme is many to because the existence of packing ring can disperse stress, reducible bone surface that leads to because of spherical head and the long-term contact of bone surface harm of collapsing reduces patient's misery and postoperative and takes out easily, has reduced secondary injury's risk.

Description

Novel hollow compression screw with detachable head

Technical Field

The utility model relates to an orthopedic implant technical field especially indicates a novel hollow forcing screw of detachable head that can be used to four limbs fracture internal fixation.

Background

With the aging population becoming more serious and the annual incidence rate of fracture gradually rising, surgical operation is a more effective treatment scheme. The internal fixation of limb fracture is a common orthopedic operation in clinic, and the market demands for internal fixation implants are large. The ball head hollow compression screw used clinically at present is generally designed in an integrated manner, the spherical head part cannot be detached, and the long-term contact between the spherical head part and the bone surface often leads to the collapse of the bone surface.

With the continuous development of new surgical theories, it is appreciated that it is important to avoid the soft tissue damage around the fracture and to ensure that the bone tissue obtains a good blood supply, and therefore, headless hollow compression screws have been gradually developed to reduce the irritation to the bone/soft tissue, but have the problem of an unsatisfactory compression effect.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a novel hollow forcing screw of detachable head that pressurization is effectual, can avoid the bone surface to sink.

In order to solve the technical problem, the utility model provides a technical scheme as follows:

the utility model provides a novel hollow forcing screw of detachable head, includes screw head and screw pole portion, the central axial of screw head and screw pole portion is run through and has been seted up the guiding hole, screw head detachable installs screw pole portion, be provided with the packing ring of the back area dogtooth between screw head and the screw pole portion.

Further, the screw rod part is of a full-thread design, and the thread pitch of the screw rod part is changed from large to small from the near end to the far end.

Further, the addendum circle diameter is 2-3 times the dedendum circle diameter at the proximal end and the middle portion of the screw shank.

Further, the proximal end of the screw shank has a tip circle diameter that is 2.5 times the root circle diameter.

Furthermore, the far end of the screw rod part is provided with a slot, an internal thread is arranged in the slot, an extension neck used for being installed in the slot is arranged on the screw head part, and an external thread matched with the internal thread is arranged on the extension neck.

Further, the screw head is provided with an inner hexagonal hole, and/or the middle part of the screw rod part is provided with an instrument operation structure on the inner side of the guide hole.

Furthermore, the washer is ring-shaped, the convex teeth are uniformly arranged on the back surface of the washer, and each convex tooth comprises a cylindrical part and a conical sharp tooth part positioned on the cylindrical part.

Further, the inner diameter of the washer is larger than the outer diameter of the screw rod part and smaller than the outer diameter of the screw head part.

Furthermore, the diameters of addendum circles of the proximal end and the distal end of the screw rod part are the same and larger than that of the addendum circle of the middle part, the diameters of dedendum circles of the proximal end and the middle part of the screw rod part are the same, and the diameter of a dedendum circle of the distal end is gradually increased from the proximal end to the distal end.

Furthermore, a transition section is arranged between the far end and the middle part of the screw rod part, and the diameter of the addendum circle and the diameter of the dedendum circle of the transition section are gradually increased from near to far.

Furthermore, the tail end of the screw rod part is provided with a self-tapping groove.

Furthermore, the novel hollow compression screw with the detachable head also comprises a self-tapping self-drilling guide pin matched with the guide hole.

The utility model discloses following beneficial effect has:

the utility model discloses a novel hollow forcing screw of detachable head pressurization is effectual, and maneuverability scheme is many to because the existence of packing ring can disperse stress, reducible bone surface that leads to because of spherical head and the long-term contact of bone surface harm of collapsing, reduce patient's misery and postoperative and take out easily, reduced the risk of secondary injury.

Drawings

FIG. 1 is a schematic view of the overall structure of the novel hollow compression screw with a detachable head according to the present invention;

FIG. 2 is a schematic view of a split structure of the hollow compression screw shown in FIG. 1;

FIG. 3 is a dimensional schematic view of the shank of the screw of FIG. 1;

FIG. 4 is an enlarged schematic view of section I of FIG. 3;

FIG. 5 is a schematic structural view of the gasket of FIG. 1, wherein (a) is a front view and (b) is a side view;

fig. 6 is a schematic structural view of the self-tapping self-drilling guide pin of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following detailed description will be given with reference to the accompanying drawings and specific embodiments.

The utility model provides a novel hollow forcing screw of detachable head, as shown in fig. 1-4, including screw head 1 and screw pole portion 2, the central axial of screw head 1 and screw pole portion 2 runs through and has seted up guiding hole 3, wherein:

the screw head part 1 is detachably arranged on the screw rod part 2, and a washer 4 with convex teeth 41 on the back surface is arranged between the screw head part 1 and the screw rod part 2;

preferably, the screw shaft 2 is of a full thread design, and the screw shaft 2 has a pitch that decreases from a proximal end 21 to a distal end 24, such that the head of the screw enters the bone more rapidly than the tail of the screw, thereby providing a continuous compression effect on the fracture surface as the screw advances;

as shown in FIG. 4, the tip diameter d1 at the proximal end 21 and middle portion 22 of the screw shaft 2 is preferably 2-3 times the root diameter d2, which is less strong in gripping cancellous bone than the shallow threads of the prior art, and the present application uses a deep thread design to increase the gripping force on cancellous bone. Preferably, the addendum diameter d1 at the proximal end 21 of the screw shank 2 is 2.5 times the dedendum diameter d 2.

The utility model discloses a novel hollow forcing screw of detachable head can be used to four limbs fracture internal fixation, and the operation process can refer to as follows:

1. after the fracture part is cut, exposing the fracture part to the fracture end layer by layer, restoring the fracture, and drilling a self-tapping self-drilling guide pin (figure 6) to reach the required depth and position;

2. the hollow drill is guided by a guide pin to drill a hole, a depth finder measures the length and a screw tap taps;

3. selecting a hollow compression screw (figure 1) and a gasket (figure 5) with proper length of the utility model, sleeving a guide pin, and screwing the hollow compression screw to a proper position along the guide pin by using a hexagonal screwdriver;

4. selecting whether the spherical head and the gasket need to be disassembled after fixation according to the reduction effect of the fracture part in the operation process;

5. after the fracture fixation is completed, whether the implantation of the hollow compression screw achieves the expected effect is checked.

The utility model discloses following beneficial effect has:

1. the head is designed in a detachable spherical shape, whether the head is matched with the washer for secondary pressurization (the screw rod part is pressurized for one time) can be selected according to the reduction effect of the fracture part in the operation process, the head and the washer can be detached again in the operation under the condition of better reduction of the fracture part after the operation, and more operation options can be provided for the clinical operation;

2. the use of the gasket can better disperse stress, greatly reduce the phenomenon of fracture surface collapse damage caused by long-term contact between the head of the screw and the fracture surface in the existing clinical use, and reduce the risk of secondary injury;

3. compared with the prior art in which the screw rod part is provided with equidistant half threads, the pressurizing effect on the fracture is limited, the screw rod part in the utility model adopts the full-thread variable-pitch design, and the continuous pressurizing and fixing effect on the four-limb fracture can be realized; the design of deep threads is adopted, so that the holding force on the cancellous bone can be increased;

4. the hollow design (namely the guide hole) can be matched with the guide pin for use, thereby guiding the direction of the screw, improving the percutaneous implantation accuracy, reducing the surgical incision, realizing the minimally invasive and reducing the stimulation to the tissue.

To sum up, the utility model discloses a novel hollow forcing screw of detachable head pressurization is effectual, and maneuverability scheme is many to because the existence of packing ring can disperse stress, reducible bone surface that leads to because of spherical head and the long-term contact of bone surface harms of collapsing plays the effect of protection screw and fracture face, reduces patient's misery and postoperative and takes out easily, has reduced the risk of secondary injury.

In the utility model, the screw rod part 2 is designed to be full-thread variable pitch, the screw rod part 2 is from the near end 21 to the far end 24, the pitch is from big diminishing, concretely, as shown in fig. 3, take the total length L of the screw rod part as an example of 16mm, the length of the near end L1 is 5mm, the length of the middle part L2 is 4mm, the total number of turns n of the thread is 14, the pitch increment Δ P is 0.046mm, the near end 21 starts the pitch P1 to be 1.452mm, the far end 24 finishes the pitch Pn to be 0.9 mm; for another example, taking the total length L of the screw shank as 18mm, the proximal L1 is 6mm long, the middle L2 is 5mm long, the total number of turns n is 16, the pitch increment Δ P is 0.036mm, the proximal 21 start pitch P1 is 1.5mm, and the distal 24 end pitch Pn is 0.9 mm. In the figure, P2 is the 2 nd turn pitch, and P3 is the 3 rd turn pitch.

In order to conveniently realize the detachable installation of the screw head 1 on the screw rod part 2, as shown in fig. 1-2, the distal end 24 of the screw rod part 2 is provided with a slot 25, an internal thread is arranged in the slot 25, the screw head 1 is provided with an extension neck 11 for installing in the slot 25, and the extension neck 11 is provided with an external thread matched with the internal thread. It can be understood that other detachable modes, such as a rotary joint, etc., which are easily conceivable by those skilled in the art, do not affect the implementation of the technical solution of the present invention.

As shown in fig. 2, the screw head 1 may be provided with an inner hexagonal hole 12 to facilitate the operation of the machine and further facilitate the torque transmission. Moreover, an instrument operation structure (not shown) can be arranged in the middle of the screw rod part 2 at the inner side of the guide hole 3, and the instrument operation structure can be an inner hexagonal hole or a plurality of inner convex key teeth, so that the screw rod part 2 can be independently operated through a matched instrument, for example, when a hollow compression screw is screwed into a bone and the screw head part 1 needs to be detached, the screw rod part 2 can be fixed through the instrument, and then the screw head part 1 is detached, so that the screw head part 1 is prevented from being unscrewed to cause the screw rod part 2 to be loosened; the screw shaft 2 is then screwed directly into the bone, for example, by means of the instrument manipulation structure without the aid of the screw head 1.

As shown in fig. 5, the washer 4 is preferably circular, the teeth 41 are uniformly arranged on the back surface of the washer 4 (in the embodiment shown in the figure, 6 teeth are uniformly arranged), the teeth 41 comprise a cylindrical portion 411 and a conical pointed tooth portion 412 positioned on the cylindrical portion 411, so that the pointed tooth portion 412 can be well engaged into bone, and the cylindrical portion 411 can properly separate the bone and the washer, thereby ensuring the firmness of the washer and avoiding excessive influence on blood transportation on the bone surface. It will be appreciated that the inner diameter d3 of the washer 4 should be larger than the outer diameter of the screw shank 2 and smaller than the outer diameter of the screw head 1, and the specific dimensions can be flexibly designed by those skilled in the art as required.

In order to achieve both the self-fixation property and the bone-holding force of the hollow compression screw, as shown in fig. 1 to 3, it is preferable that the proximal end 21 and the distal end 24 of the screw shaft 2 have the same tip circle diameter and are larger than the tip circle diameter of the middle portion 22, the proximal end 21 and the middle portion 22 of the screw shaft 2 have the same root circle diameter, and the root circle diameter of the distal end 24 gradually increases from the proximal end to the distal end. Further, a transition section 23 may be provided between the distal end 24 and the middle portion 22 of the screw shaft 2, and both the tip circle diameter and the root circle diameter of the transition section 23 become larger from the near to the far. Thus, the continuous compression fixation of the hollow compression screw to the bone is better.

As shown in fig. 2, the tip of the screw shank 2 may be provided with a self-tapping groove 26 to make the operation easier and to facilitate insertion and removal; in addition, as shown in fig. 6, the hollow compression screw of the present invention may further include a self-tapping self-drilling guide pin 5 matched with the guide hole 3 for guiding the screw direction, improving the accuracy of percutaneous implantation, reducing the incision of the operation, realizing the minimally invasive, and reducing the stimulation to the tissue.

The foregoing is a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. The utility model provides a novel hollow forcing screw of detachable head, includes screw head and screw pole portion, the central axial of screw head and screw pole portion is run through and has been seted up the guiding hole, its characterized in that, screw head detachable installs screw pole portion, be provided with the packing ring of the back area dogtooth between screw head and the screw pole portion.

2. The novel hollow compression screw with a detachable head as claimed in claim 1, wherein the screw shaft is of full thread design, and the screw shaft has a pitch that decreases from the proximal end to the distal end.

3. The new hollow compression screw with detachable head as claimed in claim 2, wherein the diameter of addendum circle is 2-3 times larger than that of dedendum circle at the proximal end and the middle portion of the screw shank.

4. The new hollow compression screw with detachable head as claimed in claim 2, wherein the proximal end of the screw shaft has a tip diameter 2.5 times the root diameter.

5. The novel hollow compression screw with the detachable head as claimed in claim 2, wherein a slot is provided at the distal end of the screw rod, an internal thread is provided in the slot, an extension neck for installing in the slot is provided on the screw head, and an external thread matching with the internal thread is provided on the extension neck.

6. The novel hollow compression screw with a detachable head as claimed in claim 1, wherein the screw head is provided with an inner hexagonal hole, and/or the middle part of the screw rod part is provided with an instrument operation structure at the inner side of the guide hole.

7. The novel hollow forcing screw with a detachable head as claimed in claim 1, wherein the washer is circular, the teeth are uniformly arranged on the back of the washer, and the teeth comprise a cylindrical portion and a conical sharp tooth portion on the cylindrical portion.

8. The novel hollow compression screw with a detachable head as claimed in claim 7, wherein the inner diameter of the washer is larger than the outer diameter of the screw shank and smaller than the outer diameter of the screw head.

9. The new hollow compression screw with a detachable head as claimed in any one of claims 2 to 8, wherein the proximal and distal tip diameters of the screw shaft are the same and larger than the tip diameter of the middle part, the proximal and middle root diameters of the screw shaft are the same, and the distal root diameter is gradually larger from the proximal to the distal.

10. The novel hollow compression screw with a detachable head as claimed in claim 9, wherein a transition section is provided between the distal end and the middle part of the screw shaft, and the diameter of the addendum circle and the diameter of the dedendum circle of the transition section are gradually increased from near to far.

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