RU2483690C1 - Device for blocked external osteosynthesis of tubular bones - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medical equipment, namely to metal constructions for osteosynthesis of fractures of tubular bones. Device contains curved plate with holes, fixing screws and spherical washers with hole in the centre and cylindrical thread. Plate is curved transversely with bend radius equal to plate width. Edges along plate are sharpened and made with toothed thread. Holes in plate are made spherical for placement of spherical washers and are located in staggered order on plate ends. Space in the centre of plate, occupying 1/3 of plate length is free of holes. Head of fixing screw has cylindrical thread for placement in hole of spherical washer. Fixing screw is made self-tapping, screw thread can cut into plate holes.

EFFECT: invention ensures reliable fixation, minimal contact of plate with bone surface, excluding development of bedsores and impairment of reparation process, as well as simplification of osteosynthesis operation.

3 dwg

Description

The device relates to medical equipment, namely to metal structures for osteosynthesis of fractures of tubular bones. In addition, it can be used for osteosynthesis of flat bones.

Known dynamic compression plate (DCP). “DCP is not only more versatile than a round hole plate, but also because of the different shape of the hole, it lacks many of the drawbacks of a round hole plate in terms of successful axial compression. Despite the fact that the DCP has stood the test of time, after a few years some of its shortcomings became apparent.

The vast contact surface between the lower surface of the plate and the bone leads to a significant violation of periosteal circulation. This was the main cause of plate-induced osteoporosis. The potential danger of such a circulatory disturbance is the formation of sequesters under the plate and the occurrence of significant mechanical problems. The quality of healing of the bone located under the plate and immediately adjacent to the fracture does not allow to increase the area of adhesion. This site heals more slowly due to disturbances in periosteal blood supply ”M.E. Muller et al. 1996. - P.240.

“The use of DCP requires the use of two guides for drills. The neutral drill guide has a centrally located hole. It allows the introduction of a screw in a neutral position, i.e. at the intersection of the two cylinders that make up the screw hole. In this central position, the drill guide leads to a displacement of 0.1 mm, so that even a screw inserted in a neutral position when tightened causes an additional increase in axial compression. As already noted, the shape of the screw head and the holes in the DCP allow the inclination of the screws in all directions. This makes it possible to better adapt the screw direction to the anatomy of a particular fracture, and also greatly facilitates the introduction of an oblique tightening screw in the direction transverse to the plate. It is necessary to emphasize again and again, where it is possible that the stability of the internal fixation should be ensured by introducing an oblique tightening screw through the plate perpendicular to the main fracture line. This principle applies to cases where the plate is used as a neutralizing one, however it acquires special significance if the plate is used as a compression plate. This technique is relatively easy to do with oblique fractures, but it can also be recommended for fixing transverse fractures of large bones, such as the femoral and tibial, if they are fixed with plates. ” M.E. Muller et al. 1996 .-- P.236.

Due to deficiencies identified, DCP has been enhanced and proposed by LC-DCP. “Changing the shape of the bottom surface. Improved blood supply.

Animal experiments have shown that the notches on the lower surface of the plate significantly improve the blood supply to the bone segments connected by the plate. To achieve a positive effect, these recesses must have an adequate width and length. The result of improved periosteal circulation and blood supply to the cortical layer was the disappearance of osteoporosis, which was thought to result from the so-called “stress protection”. It was shown that this osteoporosis associated with plate fixation occurred due to an initial circulatory disturbance and subsequent avascular necrosis, which subsequently caused intensive bone remodeling. " “LC-DCP can be used absolutely in the same cases as DCP. For an experienced surgeon, the additional benefits that provide a certain improvement in the operation of the plate are obvious. The insert must be used with the new drill guide for the LC-DCP. The old guide for DCP should not be used. To prevent inconvenience in handling, the new drill guide for the LC-DCP has the same shape as the insert. The neutral and eccentric drill guides are mounted on the same tool. Axial compression can be created only when the arrows of the drill guides (neutral too) are directed towards the fracture. To create compression (when the screw passes through the plate or outside it as a tightening one), in all cases, new cortical core screws should be used as more effective and durable. "

M.E. Muller et al. - Manual on internal) osteosynthesis. Springer-Verlag. - 1996 - S.236-244.

When using this device, there are certain disadvantages and inconveniences in the use of these devices, leading to a deterioration in the results of surgical treatment.

1. A large area of contact between the plate and the bone surface is maintained.

2. At the places of the recesses, the plate becomes less strong and its fractures occur in the marked places.

3. A significant limitation of the plane of the screw.

4. The use of a conductor complicating the operation of osteosynthesis.

The closest analogue to the claimed devices, taken as a prototype, is the POLYAX system of lockable plates.

“The POLYAX lockable plate system is designed to provide the surgeon with the maximum possible choice of screw design options: lockable with a fixed angle, lockable with a variable angle and non-lockable. As a result, fixation is performed taking into account the specific features of a particular fracture, the properties of the bone substance and the anatomical conditions.

The screw is fixed by screwing it directly into the plate hole (fixed-angle options) or into the patented polyaxial bushings (variable-angle design) located in the plate. The locking part of the screw consists of a three-way tapered thread on the screw head, designed to engage with a plate or sleeve. The bushings allow you to fix the screws at the desired angle within 30 degrees. "Non-locking screws are installed in holes with a predetermined corner or in polyaxial bushings"

Design surgeons:

Lawence Bone, MD, George Haidukewych, Ml), Roy Sanders, MD.

POLYAX. Wide-angle space. Surgical technique.

OSTEOSYNTHESIS OF THE PROXIMAL DEPARTMENT OF THE TIBERA BY THE LOCKING PLATE. De Puy. a Gohnson Gohnson compani. Registration certificate No. FSZ 2007/00362

Disadvantages:

1. A large area of contact between the plate and the bone surface is preserved, which creates a threat to the development of necrosis and the inflammatory process of the bone with a violation of the reparative process in the fracture area.

2. The lack of universalization of the use of the plate, that is, for each segment and even the localization of the fracture, a separately manufactured plate is required.

3. The conical lockable thread of the plate and screw complicates the manufacture of lockable screws and threading in the sleeve and screw.

4. The reliability of rotation of the spherical sleeve in the plate is not ensured.

Based on the information about the prototype, we compile a comparison table of the claimed device with an analogue to preliminarily formulate the essence of the proposed device and draw up a preliminary version of the formula of the invention.

The table of the claimed designs with analogues

1. 1st analogue: Dynamic bone plate DCP, LC DCP. It is used for blocked osteosynthesis of fragments of long tubular bones when using conductors, with the option of creating less contact of the plate with the bone due to cuttings (grooves) of the metal from the inside. The synthesis is carried out using guiding bushes specially created for each design.

2. 2nd analogue (prototype). POLYAX lockable plate system. The purpose of the prototype device: the implementation of the blocked osteosynthesis of the metaphyseal region of long bones. It is carried out using embedded bushings that have the ability to change the angle range during osteosynthesis, and the cone-shaped screw cutting of the sleeve and screw allows for locking blocking of the plate.

3. The claimed invention: a device for blocked immersion osteosynthesis (purpose: osteosynthesis of fractures of tubular bones), (described further in the description of the invention).

The inventive device Prototype Analogue Universal plate for blockable synthesis of bone fragments of any localization. The plate is designed for the synthesis of metaphysical fractures of the lower leg, thigh, blocked. Lockable plate. It is used for the synthesis of diaphyseal and metaphysical bone fractures. Arcuate in diameter with pointed lateral edges and serrated cutting with spherical holes, staggered. It comes into contact with bone with sharp edges and with serrated cutting. A plate with a group of holes on the expanded and curved metaphysical end and holes applied longitudinally distally. Flat. There are notches along the inner surface to reduce bone contact. A spherical washer with a cylindrical thread along its axis for blocked osteosynthesis is located in the spherical hole of the plate, which allows a screw with a significant change in angle in any direction with a deviation from the vertical axis. Bushings with a tapered internal thread, the ability to maneuver in various directions up to 30 degrees. Contact with the bone with the entire plane of the plate. In the holes of the plate there is a cone-shaped screw thread for blocked osteosynthesis. The synthesis is carried out using a guide sleeve with limited ability to change the angle of inclination. The thread on the screw head is cylindrical. Cone-shaped screw head The diameter of the spherical hole of the plate is smaller than the outer diameter of the threaded surface of the screw, and when screwed, the screw is held along the edge of the plate, and, having self-tapping properties, passes its smaller diameter. The space between the groups of holes creates conditions for the strength of the plate in the place of least resistance.

A preliminary version of the formula of the proposed device

A device for lockable immersion osteosynthesis, including a plate curved from above in the shape of a bone, possibly with cuts on the inner surface for less contact with the bone, with fan-shaped holes in the proximal section with and without an internal taper thread, as well as down the plate, are also available bushings with an internal taper thread and screws with a taper thread on the head with the possibility of changing the angle of inclination of the screw, characterized in that the plate is transversely bent with a bending radius equal to the width e plates, and its edges along are pointed and with gear cutting, in the spherical holes of the plate dispersed at the ends of the plate and arranged in a checkerboard pattern, spherical washers, with a hole in the center and a cylindrical thread, are placed to introduce a fixing screw with the possibility of changing to the desired angle tilt at the time of osteosynthesis, on the head of which there is a cylindrical thread, the diameter of the spherical hole of the plate is less than the outer diameter of the threaded surface of the screw and when screwing the screw is held along the edge of the plate, and having self-tapping properties, passes its smaller diameter, providing reliable fixation.

Technical result

The technical result of the present invention is to improve the operational and functional properties of the plate for blocked osteosynthesis: ensuring reliable fixation, minimal contact of the plate with the surface of the bone, eliminating the occurrence of pressure sores and impaired reparative process, simplifying the operation of osteosynthesis. The noted technical result is achieved by changing the shape of the plate, the location of the holes on it and the shape of the hole of the plate, replacing the guide sleeve with a washer and using a cylindrical thread inside the washer and screw head, as well as the difference in the spherical hole of the plate, which is smaller than the outer diameter of the screw surface of the screw and when screwing the screw held along the edge of the plate, and having self-tapping properties, passes its smaller diameter. The pointed edges of the serrated plate create reliable stability of the plate with the exception of its extensive contact with the bone.

Justification of compliance of the invention with the criterion of "inventive step".

The prior art does not know the signs:

1. The plate is bent across with a bending radius of the plate equal to the width of the plate, which creates a constant optimal gap between the plate and the bone when using different widths, and the longitudinal edges of the plate are pointed with serrated cutting.

2. The spherical washer replaces the guide sleeve, has an axial hole in contact with the spherical hole of the plate, which allows the screw to be tilted in any desired direction when fixing the plate.

3. There is a cylindrical thread in the washer and head of the locking screw.

4. The space free from the holes in the center of the plate and occupying about 1/3 of its length provides strength and never breaks the lock.

5. The spherical hole of the plate is smaller than the outer diameter of the threaded surface of the screw and when screwed, the screw is held along the edge of the plate, and, having self-tapping properties, passes its smaller diameter, ensuring reliable fixation.

The proposed device is presented in figures 1, 2, 3.

Figure 1. Device for blocked immersion osteosynthesis (side view).

Figure 2. Device for blocked submersible osteosynthesis (top view).

Figure 3. Device for blocked immersion osteosynthesis (transverse section of the plate in the installation area of the fixing screw).

Thus, the proposed device for blocked immersion osteosynthesis consists of a plate bent laterally with a bending radius equal to the width of the plate to ensure optimal clearance with the surface of the bone, with pointed longitudinal edges and serrated cutting and holes arranged in a checkerboard pattern. For the plate holes, a spherical washer with an internal cylindrical thread is introduced, through which a cortical or spongy fixing screw is inserted with a cylindrical thread on the screw head, which is screwed into the washer at an angle necessary to fix the bone fragments, creating a lockable plate fixation.

Variant of using the proposed device

The proposed device can be used with the simplicity of traditional bone osteosynthesis, but with an efficiency exceeding the blocked devices of the latest generation, which greatly increases the effectiveness of the treatment of patients with fractures of long tubular bones.

Schematically, the use of the proposed device can be represented as follows:

- Performing surgical access - an incision is made according to the existing surgical rules at the level of a bone fracture.

- Separate bone fragments with the release of hematoma or connective tissue formations.

- Eliminate soft tissue interposition.

- Select and simulate the necessary plate.

- Perform a reposition of bone fragments.

- Set the plate on the fragments at the level of the fracture with holding it using a bone holder.

- Through the proximal hole of the plate and the washer with the latter turning at the desired angle for reliable fixation of fragments and made using a drill, a screw is drawn into the bone and screwed into contact with the cylindrical thread of the head and the cylindrical thread of the washer.

- Carry out an additional reposition of the fragments and after drilling the bone at an angle necessary for reliable fixation of the fragments with a change in the position of the washer, screw the screw in the hole area to failure, the thread of which cuts into the edges of the plate hole, and the threads of the head are screwed into the washer thread.

- Screw the proximal lockable screws no more than two to failure, then after additional reposition through the hole of the plate and washer with a change in the direction angle when turning it, make holes and screw in the required number of screws, respectively, of the location of the synthesized fracture.

- The number of locked screws may not be limited, but for reliable fixation of the fracture it is enough to introduce two screws in the proximal and distal fragments. The remaining screws may not be lockable.

- Wound closure.

- Immobilization of the limb, depending on the nature of the fracture and the reliability of the performed osteosynthesis. Management without immobilization is possible.

Claims (1)

A device for blocked immersion osteosynthesis of long tubular bones, containing a curved plate with holes and fixing screws, characterized in that it has spherical washers with a hole in the center and a cylindrical thread, the plate is curved transversely with a bend radius equal to the width of the plate, and its edges are pointed along. and made with gear cutting, the holes in the plate are made spherical to accommodate spherical washers and are staggered at the ends of the plate, with the space in the center of the plate, occupying 1/3 of the plate length, free of holes, the head of the fixing screw has a cylindrical thread for placement of a spherical washer in the hole, the fixing screw is self-tapping, while the screw thread can cut into the edges of the plate hole.

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