RU2572302C2 - Device for bone fragment reduction in ilizarov's apparatus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment, namely to devices applicable in traumatology and orthopaedics. A device for bone fragment reduction in an Ilizarov's apparatus represents a reduction unit substituting threaded bars connecting external supports of the Ilizarov's apparatus and consists of a plate, two threaded bars (long and cross), supporting arms and nuts, and provides a precision and gradual three-plane displacement of one (distal bone fragment or extremity segment in relation to the other (proximal) bone fragment or extremity segment. The distal fragment or extremity segment is displaces along the length and axis by screwing the nuts on the long threaded bar, and across the width - on the cross one. Besides, the long threaded bar is fixed with two supporting arms and nuts on the plate that ensures an adequate degree of security for the precision displacement of the distal fragment or extremity segment and prevents deformities and strain distortion in the Ilizarov's apparatus system under the action of extremity muscle traction that is caused by the three-point fixation of the long bars.

EFFECT: invention ensures higher effectiveness and reduces the length of treatment of the patients with the Ilizarov's apparatus.

6 dwg

Description

The invention relates to medical equipment, namely to devices used in traumatology and orthopedics.

Extrafocal osteosynthesis of long bones of extremities with external fixation devices occupies an important place in orthopedics and traumatology, being the method of choice for open and high-energy fractures and false joints of bones. It has the optimal combination of atraumatic and stable fixation of bone fragments, as well as the ability to manipulate bone fragments or segments of the limbs during the entire period of wearing the external fixation apparatus.

Analogs

External fixation devices are divided into spoke, rod and spoke-rod devices of various modifications, which have their indications and contraindications. The rod-shaped external fixation devices are simpler and most acceptable in the region of the upper third of the shoulder or thigh, where due to topographic and anatomical features (articulation of the shoulder with the shoulder blade and chest and the thigh with the pelvis) it is impossible to impose a complete ring of the device. Therefore, one of the main advantages of using rod devices on the upper third of the shoulder is the simplicity and monolaterality of the position of the outer frame of the device on the damaged segment.

Criticism of analogues

However, significant disadvantages of the rod apparatuses of external fixation are:

- low repositional properties of the metal structure with the problematic management of bone fragments, both during the operation of osteosynthesis, and especially in the postoperative period;

- the frequent need for additional devices for the reposition of bone fragments;

- the use of Schansz transosseous rods with a diameter of 3.5 to 6 mm, which is associated with drilling intraosseous canals and, accordingly, a decrease in mechanical strength and osteogenic potentials of the bone. This delays the healing time of fractures, increases the risk of inflammation and can even lead to secondary bone fractures at the sites of the rods;

- a relatively quick loss of stability of the apparatus system due to bone resorption at the border with the thread of the intraosseous rods. Bone resorption also occurs around the spokes over time, however, the degree of this resorption is much smaller and can be compensated by compression or distraction between the external supports of the apparatus.

The external fixation spoke devices are more functional, controllable and minimally invasive, therefore, we selected the Ilizarov apparatus as a prototype, namely, a spoke with a persistent pad, with a rod for which lateral displacement of the distal bone fragment or distal limb segment relative to the proximal bone fragment or proximal limb segment is eliminated. , and threaded rods, by tightening the nuts on which create compression or distraction between the bone fragments.

Prototype

As a prototype of the proposed device, we have chosen the traditional extra focal osteosynthesis with the Ilizarov apparatus (Traumatology and Orthopedics: A Guide for Doctors / Edited by N.V. Kornilov: in 4 volumes. - St. Petersburg: Hippocrates, 2004 - T.3: Injuries and diseases of the lower limbs / Under the editorship of N.V. Kornilov and E.G. Gryaznukhin. - St. Petersburg: Hippocrates, 2006 - 1054 p. - S.592-719), namely, a spoke with a thrust pad, with a thrust that eliminates lateral displacement distal bone fragment or distal segment of the limb relative to the proximal bone fragment or prok of the extremal segment of the limb, and threaded rods, tightening the nuts on which create compression or distraction between the bone fragments. The spoke is fixed with emphasis on the outer frame of the apparatus using spoke fixators, nuts and brackets, and threaded rods are attached to the outer supports using nuts.

Prototype criticism

Along with the possibility of lateral traction and eliminate the displacement of the distal bone fragment or distal segment of the limb, the prototype device has significant disadvantages:

- invasiveness, namely the need for end-to-end conduction and traction of the knitting needle with emphasis through the bone and soft tissues of the limb segment for reposition of bone fragments or reduction of dislocation;

- the risk of developing inflammatory complications of the tissues through which the spoke is held with a persistent pad, and the higher, the more soft tissue is “stitched” with a spoke;

- the problematic dosage and painless correction of the position of bone fragments in the postoperative period, since a complete reduction of bone fragments or reduction of dislocation is possible only during the operation of extra focal osteosynthesis;

- insufficient manipulation properties of the prototype, due to the fact that the thrust of the spoke with emphasis is usually carried out by a tensioner, which is installed on the frame of the apparatus, tension and fix the spoke, remove the tensioner, bite and bend the end of the spoke. Since it is not necessary to bend and unbend the needle repeatedly because of the danger of its breaking at the bend, reposition of bone fragments (or reduction of dislocation) must be performed simultaneously and finally, which is not always possible;

- the imperfection of the manipulation properties of the spoke with emphasis, in addition, due to the lack of the ability to achieve reverse bone fragment or deviation of its direction from the originally specified vector;

- a small area of the persistent area of the knitting needle with emphasis causes a high load per unit area of the bone in contact with it, which, firstly, leads to resorption of the bone under the resistant area and, secondly, can lead to the immersion of the resistant area in the bone with a loss of achieved reduction bone fragment (or reduction of the distal segment of the limb) and the difficulty of extracting the spoke;

- the difficulty in achieving the precision accuracy of reposition of bone fragments by correcting the position of the displaced bone fragment in three planes: along the length, periphery (axis) and width;

- lack of clear visual control over the movement of the displaced bone fragment in width;

- when the bone fragments are repositioned or the dislocation of the distal segment of the limb is repaired in the Ilizarov apparatus, elastic deformation of the threaded rods often occurs between the external supports of the apparatus, which is caused by the counteraction of the muscles of the limb segment, the eccentric location of the bone in soft tissues and the lever properties of bone fragments under the influence of various muscle groups, not in equilibrium. This leads to distortion of efforts in the apparatus system and insufficient osteosynthesis. To prevent the curvature of threaded rods, you have to increase their number or change to more telescopic rods that are more resistant to distortion. Meanwhile, the first is associated with the need to search for additional holes on the rings that can be occupied by bolt spoke fixators, brackets or bolts, and the second is most often impossible - due to the fact that the distance between the rings of the apparatus is usually less than the length of the outer tube of the telescopic rods .

The purpose of the invention is to increase the effectiveness of treatment of patients with fractures of long bones and dislocations of limb segments in the Ilizarov apparatus.

SUMMARY OF THE INVENTION

A device is proposed (Fig. 1), consisting of parts of a standard set of Ilizarov apparatus, namely a plate (pos. 1), a longitudinal threaded rod (pos. 2), a transverse threaded rod (pos. 3), brackets (pos. 4) and nuts (item 5). Apply this device as follows. A typical extra focal osteosynthesis is performed with the Ilizarov apparatus in the treatment of bone fractures or dislocation of limb segments. For the purpose of precision and dosed movement of one (distal) bone fragment or limb segment relative to another (proximal) bone fragment or limb segment in all three planes, movement of the distal bone fragment or limb segment along the length and axis is performed by tightening the nuts on a longitudinal threaded rod (pos. .2), and in width - on the transverse (pos. 3). The three-point fixation of the longitudinal threaded rod (pos. 2) by two brackets (pos. 4) and nuts (pos. 5) on the plate (pos. 1) and the external support of the Ilizarov apparatus gives it a sufficient safety margin for the precision movement of the distal bone fragment or limb segment and excludes its deformation and distortion of stresses in the Ilizarov apparatus system under the action of traction of limb muscles. The margin of safety of the transverse bar for bending is also guaranteed and is due to the fact that its length is more than two times less than the length of the longitudinal bar - it is obvious that the shorter it is, the more difficult it is to bend. For a more complete visual control of the movement of the distal bone fragment or limb segment in width, the axis of the longitudinal threaded rod of the device should be combined with the axis of the bracket fixed to the distal external support of the Ilizarov apparatus (Fig. 2, a). Further movement of the distal bone fragment or segment of the limb in width will clearly correlate with the distance from line A, corresponding to the axis of the longitudinal threaded rod, to line B, corresponding to the axis of the bracket (Fig.2, b).

Device application example

As an example of the use of a device for reposition of bone fragments in the Ilizarov apparatus, we give the following observation.

Patient A., 59 years old, was admitted to the orthopedic department of the RTC on March 7, 13, in a planned manner with a diagnosis of a chronic posterior dislocation of the right foot with a slowly growing fracture of the ankles and posterior edge of the tibia with displacement of fragments. From the anamnesis: 1.5 months ago there was a closed fracture of the ankles and the posterior edge of the tibia with dislocation of the foot posteriorly and outwards. She was treated in the traumatology department of the RTC, where under local anesthesia, bone fragments were repositioned with reduction of the foot dislocation and immobilization of the limb with a deep plaster cast. Radiologically confirmed reduction of dislocation of the foot and reposition of bone fragments. After the swelling of the foot and lower leg subsided, the gypsum splint was transferred to a circular plaster cast, and the patient was discharged for outpatient treatment. However, after a follow-up x-ray, a month later, foot relaxation and a secondary displacement of bone fragments were revealed, about which the patient was hospitalized for planned surgical intervention.

An operation was performed under spinal anesthesia on March 13, 2013: An open reposition of the outer and inner ankles and the posterior edge of the tibia, reduction of the posterior dislocation of the right foot with osteosynthesis by the Ilizarov apparatus and fragments of Kirschner knitting needles. In this case, a skin incision was made, enveloping behind the lower third of the fibula. Displaced bone fragments are disconnected and repaired with fixation by their Kirschner spokes. Then an arcuate incision was made slightly anterior to the inner ankle, starting from the level above the ankle joint by 5 cm and continuing down and backward, 8 cm long. A sharp and blunt way reveals the fracture line and soft tissues interfering and preventing reposition of bone fragments are removed (capsule fragments, blood clots, regenerate). The Volkman triangle is repaired and fixed by Kirchner spokes inserted perpendicular to the front fracture line. Then the inner ankle is repaired and fixed with knitting needles. Intraoperative X-ray control of the ankle joint in two projections verified the direction of dislocation with a satisfactory position of bone fragments and spokes. The wounds were sutured in layers and the second stage of the operation completed the installation of the Ilizarov apparatus from two 130 mm rings connected by threaded rods at the level of the middle and lower third tibia, in each of which a pair of Kirchner spokes with a diameter of 1.5 mm and a cross angle of 60 -75 degrees. The rings are connected by threaded rods, and then in the frontal plane through the calcaneus the Kirschner spoke is drawn, stretched and fixed in a 130-mm half-ring. The latter is connected to the lower ring of the apparatus by threaded rods. Through the front of the foot held a spoke, stretched and fixed in a semicircle connected to the lower ring of the apparatus with brackets, plates and nuts. All threaded rods are locked. The Ilizarov apparatus system is stable. Aseptic balls were placed on knitting needles and dressings on postoperative wounds.

The next day, control radiography of the ankle joint was performed in the Ilizarov apparatus in 2 projections and the posterior subtalar dislocation of the foot was revealed (Fig. 4, a, b), which was an indication for the use of our device. In order to correct the posterior dislocation of the foot, it is necessary to move the lower external support of the Ilizarov apparatus (together with the foot) 2 cm anteriorly, which was dosed in the ward as follows. The threaded rods between the lower ring on the lower leg and the external support of the Ilizarov apparatus on the foot were alternately replaced by a device that is a reposition module and consists of a plate, two threaded rods (longitudinal and transverse), brackets and nuts. In this case, the longitudinal threaded rod was located on the same axis with the bracket connecting the transverse threaded rod of the device with the outer frame of the device on the foot (namely, a half ring on the heel). Dosed distraction was performed along the longitudinal rods of the device within 0.5 cm, and then along the transverse rods by 2 cm with dosed movement of the foot anteriorly and visual control of this movement along the axis position of the brackets and transverse rods (Fig. 5). Due to the three-point fixation of the longitudinal threaded rod with two brackets and nuts on the plate and the external support of the apparatus, as well as more than half the length of the transverse threaded rod, the threaded rods of the device had a sufficient margin of safety to exclude their deformation and distortion of stresses in the Ilizarov apparatus system under the action of traction limb muscles. Therefore, this movement of the foot anteriorly was metered and painless. The direction of dislocation is verified by control radiography (Fig.6, a, b).

After wound healing and removal of sutures, the patient was transferred to outpatient treatment with the recommendation to come for a checkup and dismantling of Ilizarov’s apparatus after 2.5 months. The preliminary result of treatment is regarded by us as good.

Features of utility model distinctive from prototype

Design features (distinguishing features from the prototype) of the device for reposition of bone fragments in the Ilizarov apparatus are:

- ease of assembly into a reposition module, easily replacing threaded rods connecting the external supports of the Ilizarov apparatus, and also, if necessary, removability and reverse interchangeability of the device with threaded rods;

- providing the possibility of dosed movement of the distal bone fragment or segment of the limb in three planes: along the length and periphery (axis) by tightening the nuts on the longitudinal threaded rod, and in width - on the transverse;

- three-point fixation of the longitudinal threaded rod with two brackets and nuts on the plate gives it a sufficient margin of safety with the exception of its deformation and distortion of stresses in the Ilizarov apparatus system under the action of traction of limb muscles. At the same time, the safety margin of the transverse threaded rod is due to more than half its length, compared with the longitudinal rod, and therefore, bending resistance;

- the ability to repeatedly move the bone fragment or segment of a limb in the Ilizarov apparatus - without reducing the handling properties of the device.

The technical result (advantages over the prototype) of a device for reposition of bone fragments in the Ilizarov apparatus:

- the possibility of precise and painless correction of the position of bone fragments not only during surgery, but also in the postoperative period;

- non-invasiveness, namely the lack of need for end-to-end holding and pulling of a spoke with emphasis in order to reposition bone fragments or to correct a dislocation of a limb segment;

- reducing the risk of inflammatory complications of tissues due to the lack of need for a knitting needle with a persistent pad;

- high handling properties of the device, due to the fact that the possibility of precision movements of the distal bone fragment or segment of the limb is provided in three planes: along the length, periphery (axis) and width;

- the ability to repeatedly move the bone fragment or segment of a limb in the Ilizarov apparatus - without reducing the handling properties of the device;

- providing clear visual control over the movements of the displaced bone fragment along the length, axis and width;

- a sufficient contact area of the knitting needle (or knitting needles) with the bone and eliminating their excess load per unit bone area during reposition of a bone fragment or reduction of a dislocation of the distal segment of the limb eliminates the risk of resorption of the bone under the spoke (or knitting needles) with the loss of the achieved reduction of bone fragment or reduction of the distal segment limbs

- a sufficient margin of safety for bending of the transverse (due to its length), and longitudinal (due to three-point fixation) threaded rods of the device with the exception of their deformations under the influence of muscles of a limb segment, which are usually not in equilibrium, ensures the stability of the apparatus system - as during reposition of a bone fragment (or reduction of a limb segment), and for the entire period of wearing the Ilizarov apparatus. The stability of the Ilizarov apparatus system is necessary to prevent secondary displacement of bone fragments (or limb segment) and provides optimal conditions for fracture consolidation.

Thus, the proposed device can improve the effectiveness of the treatment of patients with fractures of long bones and dislocations of limb segments in the Ilizarov apparatus.

Information sources

1) Ilizarov G.A. Clinical and theoretical aspects of transosseous and distraction osteosynthesis // Theoretical and practical aspects of transosseous and distraction osteosynthesis. - Kurgan, 1976.- S.14-24.

2) Devyatov A.A. Transosseous osteosynthesis. - Chisinau. - 1990. - 316 s;

3) Golyakhovsky V., Frenkel V. Manual on transosseous osteosynthesis using the Ilizarov method. - SPb. - 1999. - 270 s .;

4) Kaplunov O.A. Transosseous osteosynthesis according to Ilizarov in traumatology and orthopedics. - M., GEOTAR, 2002 .-- 304 p .;

5) Traumatology and Orthopedics: A Guide for Physicians / Ed. N.V. Kornilova: in 4 volumes. - St. Petersburg: Hippocrates, 2004. - T.3: Injuries and diseases of the lower limb / Ed. N.V. Kornilova and E.G. Gryaznukhina. - St. Petersburg: Hippocrates, 2006 .-- 1054 p. - S.592-719 - prototype device.

Claims (1)

A device for reposition of bone fragments in the Ilizarov apparatus, characterized in that it is a reposition module that replaces the threaded rods connecting the external supports of the Ilizarov apparatus, and consists of a plate, two threaded rods (longitudinal and transverse), brackets and nuts and provides precision and metered movement of one (distal) bone fragment or limb segment relative to another (proximal) bone fragment or limb segment in three planes, while the distal bone fragment or limb segment along the length and axis, tighten the nuts on the longitudinal threaded rod, and the width on the transverse, in addition, fixing the longitudinal threaded rod with two brackets and nuts on the plate gives it a sufficient margin of safety for the precision movement of the distal bone fragment or segment of a limb and the exclusion of its deformation and distortion of stresses in the Ilizarov apparatus system under the action of traction of limb muscles, which is due to three-point fixation of longitudinal rods.

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