RU129380U1 - DEVICE FOR EXTERNAL FIXATION OF THE metacarpal bones and phalanx of the fingers of the hand - Google Patents

Abstract

1. Apparatus for external fixation of the metacarpal bones and phalanges of the fingers, consisting of a supporting rod and two mini-fixers, characterized in that the mini-fixer bolt at the end of the threaded part has a cut in the channel, and, starting from the middle of the cut, the bolt channel narrows and the supporting rod made threadless. 2. The apparatus according to claim 1, characterized in that the Kirschner or Ilizarov spokes can be used as a threadless support rod.

Description

The utility model relates to medicine, in particular to traumatology, namely to hand surgery and can be used to fix short tubular bones of the hand, in case of fractures, osteotomies, after removal of a bone tumor with a remaining bone mass deficit. Situations are possible when the surgeon prefers external fixation as fixation, since he does not have the ability or equipment for immersion osteosynthesis. For example, in case of open and infected fractures and other clinical situations, when there are contraindications for performing bone osteosynthesis (with a plate and screws) or intramedullary osteosynthesis (with rods or knitting needles) (1, 2). Also, indications for the use of external fixation may be the presence of comminuted or intraarticular fractures, requiring the use of distraction methods in treatment.

The following can be used as options for external fixation: various modifications of dynamic traction (dynamic traction) - structures made of Kirchner spokes. These methods allow you to set a satisfactory distraction, while they are light in weight and small, which makes them convenient for patients. The disadvantage of these methods is the lack of stability, which requires more careful monitoring by a doctor, and sometimes additional fixation with gypsum (3).

There are many techniques using external fixation devices. Two main types of apparatuses are used: rod, mono-plane apparatuses and apparatuses consisting of modules of rings or half rings (similar to Ilizarov apparatus). All of them have sufficient stability. Semi-ring devices make it possible to establish distraction, while correcting its plane in time (4). However, these devices are subjectively quite inconvenient for patients, as they are too bulky for distal segments. Their use on the phalanges of the fingers of patients is concerned about their significant weight and pressure on the soft tissues of neighboring fingers (5, 6).

There are techniques using skeletal traction, but in clinical practice they are used very rarely, since in all respects they lose to the above methods. In relation to the fixation of the bones of the hand, this technique delivers the greatest inconvenience to patients, while not having sufficient stability

Thus, in cases that do not require a change in the distraction plane (stepwise correction), the monoplane external fixation apparatus (AFF) (3) is the method of choice (Figs. 1, 3, 5, 6). However, given that AVF always, to one degree or another, cause subjective inconvenience to patients, there remains a need to further improve this type of apparatus in order to increase their subjective convenience.

The closest device to the technical nature and functionality of the invention was monoplane AVF production Kurgan NIIITO (7) (Fig.7, 8, 9). The disadvantage of this device, in our opinion, is the excessive weight and dimensions of the structure.

The technical result is to facilitate the design of monoplastic AVF while maintaining rigidity sufficient to fix a short tubular bone; reducing the likelihood of displacement and minimizing the inconvenience of using the device, both for the patient and for the surgeon, due to the low weight of the structure; reducing the size of the structure allows you to impose it on smaller (distal) bones.

The result is achieved due to the fact that the device consists of two mini-fixers, consisting of a bolt, which has a cut in the channel at the end of the threaded part. The clearance is less than the diameter of the supporting rod. Moreover, starting from the middle of the cut, the bolt channel narrows to a diameter smaller than the diameter of the bearing rod, M5 nuts and reduced washers, two of which have special grooved notches (grooves) made with the possibility of rigid fastening of transosseous spokes, and as a threadless bearing rod a Kirschner spoke or an Ilizarov spoke can be used. Kirschner spokes are used as transosseous elements.

The figures depict:

Figures 1-9 are examples of other external fixation devices for hand bones:

Figure 1 - AVF V.P. Rusanova et al.

Figure 2 - AVF Andruson - Goloborodko (view of the brush)

Figure 3 - AVF Andruson - Goloborodko

Figure 4 is an example of the layout of the AVF for a fracture of the base of the middle phalanx.

Figure 5 - AVF Acumed

Figure 6 - Suzuki AVF

Figure 7 - monoplane AVF Kurgan Research Institute in assembled form

Figure 8 is a diagram of the overlay AFV Kurgan Research Institute with a fracture of the phalanx

Figure 9 is a layout diagram of a minifixer of the Kurgan Research Institute on a supporting rod.

Figure 10 - General view of the apparatus for external fixation of the metacarpal bones and phalanges of the fingers: 1 - mini-fixator, 2 - transosseous elements, 3 - supporting rod, 4 - mini-fixer bolt, 5 - nut for locking the mini-fixer on the supporting rod, 6 - nut holding washers , 7 - washers with notches, 8 - intermediate washer.

Figure 11 - diagram of the bolt for the mini-fixer of the apparatus for external fixation of the metacarpal bones and phalanges of the fingers: 4 - mini-fixer bolt, 9 - channel in the bolt, 10 - conical narrowing of the bolt channel, 11 - longitudinal slotted cut, 12 - grooved notch on the bolt, 13 - the hexagonal part of the bolt, 14 - the threaded part of the bolt.

Figure 12 - diagram of the mini-fixture of the apparatus for external fixation of the metacarpal bones and phalanges of the fingers on the supporting rod: 3 - the supporting rod, 4 - the mini-fixture bolt, 5 - the nut for locking the mini-fixture on the supporting rod, 6 - the nut holding the washers, 7 - washers with notches, 8 - intermediate washer, 10 - conical narrowing of the bolt channel, 11 - longitudinal slotted cut, 15 - grooved notches in the washers,

The proposed design is made of inert metal, for example, stainless steel, and consists of two mini-fixers 1 mounted on a threadless bearing rod 3 by means of a nut 5 and a specially made bolt design (longitudinal slotted cut 11 into the bolt channel at the end of the threaded part 14 and, starting from the middle cut, narrowing of the 10th channel of the bolt) holding transosseous elements 2.

The mini-fixture 1 consists of a bolt 4 with a thread diameter of M5, two nuts 5, 6 with a diameter of thread M5, two washers 7, (with an inner diameter corresponding to the diameter of the legs of the bolt 4), with grooved notches (grooves for rigid fastening of the spokes 2) 15 with a depth sufficient for laying spokes tangential to the inner diameter, similar to the device of the Kurgan Research Institute (Fig. 9), one intermediate washer 8, the inner diameter corresponding to the diameter of the legs of the bolt M5, but without notches.

As transosseous elements 2, Kirschner spokes (three spokes for each minifixer) can be used.

As a supporting rod 3, a Kirschner spoke can be used, which is strong enough to hold short tubular bones, which is confirmed by its viability during intramedullary osteosynthesis. If necessary, greater strength (for example, on the metacarpal or metatarsal bones), an Ilizarov spoke, that is, a spoke with a large diameter, can be used. Then this will require the use of a minifixer with a wider channel in the minifixer bolt.

The minifixer bolt is made as follows (11):

In the center of the bolt there is a longitudinal hole - channel 9, with an inner diameter corresponding to the diameter of the supporting rod, for example, Kirschner spoke or Ilizarov spoke. The channel starts from the hexagonal part of the bolt 13, and at the end of the threaded part 14 a longitudinal slotted cut 11 is made into the channel of the bolt along the axis of the bolt. The cut gap has a size smaller than the diameter of the supporting rod. A length of approximately two heights of the M5 nut. Starting from the middle of the longitudinal slotted cut 11, the channel conically narrows 10 to a diameter smaller than the diameter of the supporting rod. On the hexagonal part 13 of the bolt on the inner side (from the thread side) there is a grooved notch 12 (a groove for fixing the Kirschner needle), which is tangential to the threaded part of the bolt.

Fixation (on the example of a phalangeal diaphysis fracture) is carried out as follows: pre-assemble a set of two mini-fixers 1 and string them on a supporting rod 3. The mini-fixers 1 on the supporting rod 3 are oriented with the hexagonal part 13 of the bolts 4 towards each other. Mini-fixers are assembled by sequentially threading washers 7, washers 8, washers 7, nuts 6 and nuts 5. The notches on both washers 7 are oriented towards the washer 8. The nuts 5 on the mini-fixers bolts are installed without covering the cut area, away from the conical displacement for the possibility of free sliding of the mini-fixture on the supporting rod. The nuts 6 are diverted from the cap of the bolt distally, for the possibility of free installation of the "bone" spokes 2 in the notches 15 on the washers 7 and in the notches 12 on the bolt 4.

Transosseous elements are carried out: 3 spokes in each fragment. The spokes located in one fragment must be at an angle to each other.

The reposition is performed in the usual manner for each localization.

Further, after the reposition step, by tightening the nut 6 to the hexagonal part of the bolt, the washers are “pressed” and the transosseous elements are thus rigidly fixed.

By means of a nut 5, namely by “unscrewing” it to the distal end of the bolt, to the end of the threaded part, the mini-fixer is fixed on the supporting rod. At the same time, nut 5 clamps the supporting rod as an anchor mechanism due to a design feature - sawing of a bolt and narrowing of its channel.

The advantage for the patient of this device is its ease and convenience, and for the surgeon, the installation and operation technique.

This device is suitable for fixing short tubular bones of the hand: metacarpal bones (including the first metacarpal bone), and the phalanx of the fingers (except for the nail phalanx). The most suitable bones for fixation in this way, in our opinion, are the middle phalanges, which are small in size and have a narrow marrowy canal, which create technical difficulties in laying other AVFs and do not allow the pair of spokes to be inserted intramedullary.

The adequacy of the stiffness of the supporting rod in the form of a Kirschner or Ilizarov knitting needle is confirmed by the fact that when performing intramedullary osteosynthesis of the metacarpal bone or phalanx of the fingers, the Kirschner spoke (while experiencing a similar load) consolidation is noted, and in our clinical practice and available literature we did not note cases of deformation or fracture of the spokes.

Clinical example: to clarify the viability of the apparatus, this AVF was superimposed in the experimental laboratory on the rabbit’s humerus after osteotomy. For the experiment, we used a Chinchilla rabbit, a 2.5 kg male involved in the experimental study of reparative osteogenesis, which during the experiment required fixation of the osteotomy bone, and the fracture zone should not be affected by the fixators so as not to affect the histological picture. The operation was carried out in accordance with the rules of humane relations with animals.

Under intravenous anesthesia after osteotomy, 3 knitting needles were made into fragments and clamped into mini-fixers. The reposition and fixing of mini-fixators on the Kirschner spoke was carried out. In a clinical test, stable fixation of the bone was achieved: with passive movements of the rabbit's limb, mobility between the fragments was not observed. The fusion took place in normal terms: according to the histological examination, the presence of bone callus was noted by three weeks.

List of references

1. Volkova A.M. Hand surgery. T.1. - Yekaterinburg: IPP "Ural Worker", 1991. - 300 p.

2. Volkova A.M. Hand surgery. T.3, - Yekaterinburg: IPP "Ural Worker", 1996. - 208 p.

3. Nakonechny D. G., Rodomanova L. A., Netylko G. I., Lushnikov S. P. Treatment of fractures of the tubular bones of the hand using trapionic methods of osteosynthesis. - Materials of the congress: Pirogov scientific-practical conference "Osteosynthesis and endoprosthetics", Moscow, 2008. Page 134.

4. Volkov M.V., Hovhannisyan O.V. "The treatment of injuries of joints and bones using the apparatus of the authors." - T .: "Medicine" b 1978 203 p.

5. Andruson M.V., Goloborodko S.A. The use of the rod apparatus of external fixation in the treatment of damage to the brush. \\ "Orthopedics, traumatology and prosthetics." - No. 7. - 1989. - P.37-39

6. Goloborodko S.A. Treatment of stale fractures of the base of the 5 metacarpal bone with a rod apparatus of external fixation // "Pediatric Traumatology, Traumatology and Prosthetics". - 2001, No. 3, S.15-17.

7. Chubarova V.M. Outpatient treatment of the effects of brush injuries by the method of G.A. Ilizarov // Outpatient surgery. - 2002. - N 3. - S. 48-48

Claims (2)

1. Apparatus for external fixation of the metacarpal bones and phalanges of the fingers, consisting of a supporting rod and two mini-fixers, characterized in that the mini-fixer bolt at the end of the threaded part has a cut in the channel, and, starting from the middle of the cut, the bolt channel narrows and the supporting rod made threadless. 2. The apparatus according to claim 1, characterized in that as a threadless support rod can be used Kirschner needle or Ilizarov needle.

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