RU2257866C2 - Extracortical fixing device - Google Patents

Abstract

FIELD: medicine, traumatology, orthopedics.

SUBSTANCE: the present innovation deals with fixing osseous fragments in case of a foreign body in medullary cavity (intramedullary rod, endoprosthesis' pedicle, etc.). Extracortical fixing device contains a shaft to be fixed to the support of compression-distraction apparatus designed as a hollow rod with internal thread, an immersion part for the contact with a bone as parallel hook-like grips at curvature radius being above the haft of osseous circumference and eccentrically connected with the shaft, a clamping sharp rod at external end to be screwed into the shaft. The innovation provides insignificant traumatism during interference, excludes the damage of the main vessels and nerves.

EFFECT: higher efficiency of fixation.

9 dwg, 1 ex

Description

The present invention relates to medicine, namely to traumatology and orthopedics, and can be used for reposition and fixation of bone fragments in external fixation devices in the presence of a foreign body in the bone marrow cavity (intramedullary shaft, endoprosthesis leg, etc.).

Known fixative for the treatment of fractures of the diaphysis of tubular bones (A.S. No. 240917 from 04/01/1969; Bulletin No. 13), which includes a bracket with notches on the inner surface and an opening for a pressure bolt that fixes the fixative to the bone.

This device has the following disadvantages:

1. The device cannot be fixed in the transosseous apparatus, which limits its scope;

2. There is no possibility to ensure constant dynamic compression at the place of contact of the retainer with the bone, which can lead to destabilization of the retainer;

3. A sufficiently high invasiveness when installing and removing the latch;

4. The "points" of contact of the retainer with the bone (notches of the inner surface of the ring on one side and the bolt on the other) are located on one another in the same plane along the radius of the bone. This reduces stability, especially lateral, fixation by the bone structure.

Closest to the proposed is the “Percutaneous compression clamp” (A.S. No. 245985 dated 06/11/1969; Bulletin No. 20), which contains two bent rods, a sliding sleeve with a presser foot. The disadvantages of this device are:

1. A sufficiently high invasiveness when installing and removing the latch;

2. The description of the device does not stipulate the possibility of fixing it in the supports of the transosseous apparatus;

3. The "points" of contact of the retainer with the bone (inner surfaces of the legs) are located opposite each other in the same plane. This reduces stability, especially lateral, fixation by the bone structure. In this regard, this device cannot be used as an independent fixing element.

The proposed device is devoid of these disadvantages. When using it, a minor invasiveness of the intervention is ensured, damage to the main vessels and nerves is excluded, there is no direct contact of the developed device with an intranostally foreign body (shaft, prosthesis leg, etc.), stable fixation of the bone fragment ensures its positive properties. The result of the invention is achieved due to the fact that the latch has a clamped pointed rod with a turnkey head at the outer end, a shank for fastening to the support of the compression-distraction apparatus is made in the form of a hollow rod with internal thread, and the clamp rod is screwed into the shank, the immersion part for contact with bone is a parallel hook-like legs with a radius of curvature greater than half the bone circumference, eccentrically connected to the shank.

List of figures illustrating the invention.

Figure 1 - Extracortical retainer (top view).

Figure 2 - Extracortical retainer (side view).

Figure 3 - The principle of use of extracortical fixative.

Figure 4 - X-ray of a patient with a fracture of the femur under the leg of the endoprosthesis (anteroposterior projection).

Figure 5 - X-ray of a patient with a fracture of the femur under the leg of the endoprosthesis (lateral projection).

6 - X-ray of a patient with a fracture of the femur under the leg of the endoprosthesis after an extrafocal osteosynthesis using extracortical fixative (anteroposterior projection).

Fig.7 - Photo of a patient with a fracture of the femur under the leg of the endoprosthesis after an extrafocal osteosynthesis using extracortical fixative.

Fig. 8 is an X-ray diffraction pattern of the same patient with an overgrown femoral fracture under the leg of the endoprosthesis after removal of the external fixation apparatus (anteroposterior projection).

Fig. 9 - X-ray diffraction pattern of the same patient with an overgrown femoral fracture under the leg of the endoprosthesis after removal of the external fixation apparatus (lateral projection).

The device consists of two main parts: the submersible part, by means of which the contact of the fixator with the bone is made, and the external one, which is attached to the support of the compression-distraction apparatus. The submersible part of the extracortical fixator has two hook-like legs (1), which occupy more than the semicircle of the bone. With their base, the legs are rigidly and eccentrically connected to the shank (2). The shank (outer part) of the retainer is a hollow shaft with an internal metric thread. A pointed rod (3) is screwed inside the shank, having a turnkey head (4) on its base. In this case, the shank (2) is connected to the legs (1) so that the pointed rod (3) is eccentrically located outward relative to the radius of curvature of the legs (1).

Two paws in the device are necessary to increase the stability of its fixation, especially the lateral. The use of one "wide" foot is undesirable due to the danger of the formation of a pressure sore on the bone, the occurrence of a "cavity", which can cause an infectious complication. The use of more paws (three or more) will not increase the stability of the device, but will increase its bulkiness and trauma of the installation. The radius of curvature of the legs (more than half the circumference of the bone) and the eccentric fixation of the shank to them are necessary so that when unscrewing the pointed rod he pressed the bone not only to the inner surface of the legs opposite it, but also a force appeared that pressed the bone “inward” of the legs. Thus, when a pointed rod is unscrewed after it stops against the bone, there are at least four “fixation points” of the bone: at the point of contact between the tip of the rod and the bone, on each of the legs opposite the pointed rod and on the concave surface of the legs. A turnkey head on the outer end of the pointed rod is necessary to facilitate screwing it in and maintaining the stability of the structure over time by dosed screwing the rod.

Use the proposed device as follows (figure 3). The radiograph determines the optimal location of the extracortical fixator (distance from the fracture site, localization of the great vessels and nerves). After that, under aseptic conditions, a channel is formed from the incision equal to the width of the immersion part to the bone to the soft tissues. The working part of the extracortical fixator is inserted into the formed channel, orienting it so that the bone comes into contact with the inner surface of the legs. After that, the pointed rod is screwed first, until it stops against the bone, and then, even more twisting the rod, they achieve a tight “compression” of the bone with paws on one side and the tip of the rod on the other. This provides a high degree of fixation of the fixative on the bone. The shank of the device is fixed to the external support of the transosseous apparatus, for example, with a standard L-shaped clamp for screw rods. If necessary (depending on the length of the bone fragment), two extracortical fixators can be installed. The second fragment of the bone, in the presence of a foreign body in its bone marrow cavity, is also fixed with one or two extracortical fixators. If the fragment does not contain a foreign body, it is fixed with Kirschner spokes or screw rods, which, in turn, are fixed in the external support (s). Then, using techniques of transosseous osteosynthesis, the fracture is repositioned and fragments are stabilized in the external fixation apparatus until fusion.

The specified device can also be used to fix the main bone fragments, having an advantage over knitting needles and rods, for example, in the case of osteoporosis. In addition, this device can be used for osteosynthesis of oblique, helical and comminuted fractures.

We present the clinical observation of the use of the device for reposition and fixation of bone fragments.

The 6th Dvoretsky IM, 60 years old, medical history No. 118, 03/02/2002, received a closed comminuted fracture of the left femur under the leg of the endoprosthesis (Figs. 4, 5). On March 21, 2002, the patient underwent closed reposition and fixation of the fracture using an external fixation apparatus. In this case, the proximal fragment was fixed using two extracortical fixators (Fig.6). The stability of osteosynthesis allowed us to begin the early restoration of support function and limb movement (Fig. 7). The fracture was healed, the device was dismantled 2.5 months after the operation (Fig. 8, 9).

Claims (1)

Extracortical retainer containing a shank for attachment to the support of the compression-distraction apparatus, an immersion part for contact with the bone, characterized in that it has a clamped pointed rod with a turnkey head on the outer end, the shank for fastening to the support of the compression-distraction apparatus is made in the form hollow shaft with internal thread, and the pressure rod is screwed into the shank, the immersion part for contact with the bone is a parallel hook-like legs with a radius of curve they are more than half the bone circumference eccentrically connected to the shank.

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