RU2585735C1 - Device (propeller) for locking osteosynthesis of fractures of bones of locomotor apparatus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to traumatology and orthopaedics, and aims at treating bone fractures of locomotor apparatus. Device for blocking osteosynthesis of bone fractures of locomotor apparatus is made in form of screw with elongated head, thin cap, and cylindrical screw thread from under cap to half head length, and lower, down to head end, there is no thread, with transition to conical head edge. Diameter of unthreaded part is less than diameter of threaded part of head, and is sufficient for passage through threaded hole of plate without any clearance, with penetration of its threadless part beyond plate edge, which protects screw head against failure.

EFFECT: invention provides reliable fixation and simplification of osteosynthesis procedure.

1 cl, 1 tbl, 1 dwg

Description

The invention relates to medicine and medical equipment, namely to traumatology-orthopedics, and is intended for the treatment of fractures of bones of the musculoskeletal system.

A description of the screws used in the osteosynthesis of bone fractures of various locations is known. That is, the general characteristics of the screws used in traumatological practice are given.

M.E. Muller, M. Allgover, R. Schneider, X. Willinegger.

Guide to internal osteosynthesis.

The technique recommended by the AO group (Switzerland), Springer-Verlag, 1996. - S. 179-185.

“The screws differ in the method of their implantation into the bone, function, size, and also in the nature of the bone for which they are intended. Thus, we distinguish self-tapping and non-tapping screws, tightening screws, cortical and spongy screws for large and small fragments.

Self-tapping and non-tapping screws

Self-tapping screws are designed in such a way that, after drilling an auxiliary hole in the bones, they are inserted by simple twisting. The auxiliary hole is slightly larger than the diameter of the screw body.

Non-self-tapping screws require preliminary drilling of the auxiliary hole and careful threading in the cortical layer of the bone with a tap whose thread exactly matches the thread profile of the screw.

Cortical and spongy screws

Cortical screws are threaded along their entire length. They are not self-tapping, therefore, before introducing them, it is necessary to cut the thread with a tap.

Spongy screws are characterized by a relatively thin body and a wide and deep thread. This increases the ratio of the outer diameter of the thread to the diameter of the body and gives such a screw a significantly greater fixing force in the thin trabecular bone, which is characteristic of the metaphysical and epiphyseal parts of the bone.

In order to allow patients early movements of the limbs after internal fixation, as well as a limited load, it is necessary to protect the majority of fracture zones fixed with tightening screws with a plate. Such a plate protects the interfragmental compression achieved by the use of tightening screws from all the twisting, bending and shear forces. ”

The screws provided have been and are used to date. They are used as independent fixators of bone fragments, but their main application is for fixing plates holding bone fragments, depending on its functional purpose.

In particular, neutralizing, supporting, compressive, and compression plates are distinguished. Their functional properties largely depend on the screws used. In particular, the principles of osteosynthesis began to change with the use of blocking plates with blocking screws.

Closer to our device is a locking screw, reflected on the website http://rotormed.net/katalog/vinty-s-konicheskoy-rezboy/, and is offered for viewing in the form of drawings, see Appendix No. 1.

The main feature is that they are used for blocking osteosynthesis. Their main design feature is a cone-shaped screw thread on the screw head, which coincides with the thread in the plate, and when screwing, blocking of the plate with the screw is created.

The negative points in the properties of this screw are as follows.

- The cone-shaped screw thread on the screw head complicates the production of screws.

- Difficulties in tapering a hole in a plate.

- The weakness of the body of the screw under the head, due to which, when the plate is loaded, the heads break off, followed by a complication of the postoperative period.

The table of the claimed designs with analogues

The first analogue. “The screws differ in: the method of their implantation into the bone, function, size, as well as the nature of the bone for which they are intended. Thus, we distinguish self-tapping and non-tapping screws, tightening screws, cortical and spongy screws for large and small fragments. "

2. Analogue (prototype). Closer to our device is a locking screw. The main feature is that it is used for blocking osteosynthesis. Their main design feature is a cone-shaped screw thread on the screw head, which coincides with the thread in the plate, and when screwing, blocking of the plate with the screw is created.

The objective of the invention is to increase the fixing properties of the screw by lengthening the head and changing the shape of the screw thread on the screw head and, accordingly, on the hole of the plate, leaving the portion of the lower part of the head free from screw thread in order to prevent the screw head from breaking and improve the quality of surgical treatment of patients with broken bones -motor apparatus.

The claimed invention: A device (screw) for blocking osteosynthesis of bone fractures of the musculoskeletal system (reflected further in the text of the invention).

The preliminary version of the claims

The device (screw) for blocking osteosynthesis of bone fractures of the musculoskeletal system is a device with a screw thread and a head with a cone-shaped screw thread, characterized in that it looks like a screw with an elongated head with a thin head and a cylindrical screw thread immediately under the head, up to half the length the head, and then down to the end, its thread is absent, with a transition to a conical section of the head, and the diameter of the uncut section is less than the diameter of the threaded part, sufficient for the passage of the threaded holes of the plate, without backlash with penetration by its threadless mass over the edge of the plate, protecting the screw head from stalling.

Technical result

The technical result of the present invention is to improve the operational and functional properties of locking screws for blocked osteosynthesis: ensuring reliable fixation, simplifying the operation of osteosynthesis. The marked technical result is achieved due to a change in the shape of the screw head, the presence of a screw thread on its upper part and the thread of the lower part of the screw head free from thread, which ensures the freedom of entry of the screw head, in the presence of a cone-shaped cut on the edge of the screw head, when switching to the screw shaft that is inserted into the plate, excluding the occurrence of oscillations, with blocking by a cylindrical thread of the plate and screw threading on the screw head.

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

No signs are known from the prior art:

1. The screw head is elongated and has a cap and a screw thread in its upper part, which occupies half the length, the lower half is free from screw thread, and on the edge of it is a cone-shaped cut.

2. Functional simplification of the operational process of introducing screws into the plate and bone without destroying the structure of bone screw cutting.

The proposed device is presented in FIG. one.

FIG. 1. Device (screw) for blocking osteosynthesis of bone fractures of the musculoskeletal system

It is a screw with a head and a shaft.

In details, he looks like this.

The head is elongated, the cap on top is 2, larger in diameter than the head itself, in the center there is a turnkey socket - 1, immediately under the cap there is a threaded part half the length of the head - 3, then a threadless part of the head - 4, then a conical section of the head - 5 connects it to the shaft of the screw - 6.

Variant of using the proposed device

A device (screw) for blocking osteosynthesis of bone fractures of the musculoskeletal system can be used with the simplicity of traditional bone marrow osteosynthesis, but with an efficiency exceeding the blocking devices of the latest generation, which significantly increases the effectiveness of treatment of patients with fractures of long tubular bones.

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

- Carry out an incision according to existing surgical rules at the level of a bone fracture.

- Allocate fragments.

- Select the necessary device - the plate.

- Set the plate with the reposition of fragments and holding it in the fracture area.

- Drill a hole in the bone at an angle created in the plate using a conductor, and insert a screw

- Screw the screw into the proximal opening incompletely with additional reposition of fragments.

- Insert a screw into the distal opening of the plate with fixation of bone fragments with radiological confirmation of the correct position of the fragments and tighten all other screws provided.

- Heal the wound.

Claims (1)

A device for blocking osteosynthesis of bone fractures of the musculoskeletal system, characterized in that it is made in the form of a screw with an elongated head and a thin hat and a cylindrical screw thread directly under the cap to half the length of the head, and then down to the end its thread is missing with a transition to a conical a cut of the head, and the diameter of the uncut portion is less than the diameter of the threaded part of the head, sufficient to pass through the threaded hole of the plate, without play, with the penetration of its threadless part beyond the edge of the layer us, protecting the screw head from breakdown.

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