WO2012007910A1

WO2012007910A1 - Device for the cerclage of fractured bones and system for the cerclage of fractured bones comprising such device

Info

Publication number: WO2012007910A1
Application number: PCT/IB2011/053117
Authority: WO
Inventors: Nilli Del Medico; Concetto Battiato
Original assignee: Intrauma S.R.L.
Priority date: 2010-07-13
Filing date: 2011-07-12
Publication date: 2012-01-19
Also published as: IT1401010B1; ITTO20100604A1

Abstract

The present invention refers to a device (1) for the cerclage of fractured bones and to a system for the cerclage which uses said device. The cerclage device (1) according to the invention comprises a cerclage wire (3), a plurality of spacers (5; 5'; 5' ';25) arranged on said wire and slidable thereon and locking means which allow locking said spacers which respect to said wire at the desired positions; the device according to the invention also comprises one or more safety wires or threads (11) which connect said spacers (5; 5'; 5' '; 25) to each other, such that, even in the case of breakage of said cerclage wire or thread, said spacers are maintained fixed to each other by said one or more safety wires or threads and do not risk being dispersed in the body of the patient.

Description

"Device for the cerclage of fractured bones and system for the cerclage of fractured bones comprising such device"

DESCRIPTION

Technical Field

The present invention refers to a device for the cerclage of fractured bones.

The present invention also refers to a system for the cerclage of fractured bones which uses said device.

Prior Art

In the field of orthopedic surgery, the use of cerclage wires is known in the case of very serious fractures or in bone reconstruction procedures. Such cerclage wires are implanted in a permanent manner in order to keep the bone portions together .

In particular, the object of said cerclage wires is to apply a circumferential compression force to the bone portions; to reach such object, the cerclage wire is tightened around the bone and then locked.

Generally, said wires are metal wires, even if the use of wires made of plastic material is known.

A cerclage wire is illustrated, for example, in US 5,993,452. Also known are cerclage systems that comprise a plate arranged on the bone and plurality of cerclage wires for maintaining said plate tightly coupled to the bone.

On such matter, with reference to Figure 1A, a cerclage system 100 is illustrated of known type, applied to a fractured bone, in particular to a femur which has a trochanteric fracture. The cerclage system 100 comprises a synthetic plate 101 which abuts against the bone and a plurality of cerclage wires 103 which are wound around the fractured femur and are tightened thereon, in a manner so as to keep the plate 101 coupled and in close contact with said femur. For such purpose, the plate 101 provides for a plurality of seats 105, and a corresponding cerclage wire 103 passes through each of such seats.

An analogous cerclage system is known, for example, from US 2006/0058795.

EP 791 338 describes a cerclage device which comprises fixing devices provided with a plurality of through holes and a cerclage wire that passes one or more times through said through holes of said fixing device; the cerclage wire is tightened in a manner so as to lock the fixing devices against the bone and the through holes are tightened in a manner so as to lock the cerclage wire and prevent its loosening .

In US 2006/122613, rather than a single cerclage wire, two separate wires are used that are partially overlapped with each other, a fixing device being provided for at the overlap region; also in this case, the cerclage wires are tightened on the bone, and once they are in the desired position they are locked in position via the fixing device.

A major drawback of the known cerclage wires is linked to the risk of onset of bone tissue necrosis at the zone in contact with the cerclage wires.

Such risk is due to the fact that the cerclage wires must be firmly tightened on the bone in order to effectively keep the bone portions together or the bone and the synthetic plate together; the high pressure exerted by the cerclage wires on the bone can lead to an insufficient blood circulation in the bone tissue, and to a consequent necrosis.

In order to remedy such drawback, cerclage devices were recently ideated comprising a cerclage wire or thread and a plurality of spacers, arranged on said wire or thread at a certain distance from each other, such to reduce the extension of the contact zones between said wire or thread and the bone to which it is applied: in such a manner, the risk of onset of necrosis is reduced.

With reference to Figure IB, a cerclage system 200 is illustrated, achieved as follows: said system comprises a synthetic plate 201 provided with seats 205 for housing corresponding cerclage devices 210; each of said cerclage devices 210 in turn comprises a wire 203 and a plurality of spacers 207 arranged on said wire 3, which allow maintaining the wire 3 at a certain distance from the bone to which the system 200 is applied. The spacers 207 are obtained in a manner so that they can slide along the wire 203 and the cerclage device 1 also comprises locking means suitable for preventing such sliding, such to be able to fix said spacers 207 in the desired position. Both the wire 203 and the spacers 207 are made of materials adapted for surgical use. A cerclage system of this type, even if it has proven its ability to avoid the risk of necrosis, is not drawback-free. In particular, it was found that the cerclage wires, although made with suitably selected materials, over time risk wearing down due to the stresses to which they are subjected once they are tightened around the fractured bone. Sometimes, the wires can even break.

In case of breakage of the cerclage wire, there is the risk that the spacers result free to move away from the fractured bone, and that they move inside the body of the patient.

The main object of the present invention is to provide an improved cerclage device and a cerclage system using one or more such cerclage devices that allow preventing such risk.

These and other objects are reached by means of a cerclage device and a cerclage system as claimed in the claim set.

Disclosure of the Invention

According to the invention, the cerclage device, in addition to the cerclage wire on which the spacers slide and can be locked, comprises one or more safety wires or threads which connect said spacers to each other.

Due to such expedient, even in the case of breakage of the cerclage wire or thread, the spacers are maintained fixed to each other by said one or more safety wires or threads, such that it is possible to prevent the spacers from dispersing in the body of the patient.

Advantageously, said one or more safety wires or threads are sized in a manner so as to be mounted loose between the spacers of the cerclage device, such that they are not subjected to any stress during the use of said device, thus avoiding the risk that they are worn down or subsequently break .

Still according to the invention, a plurality of cerclage devices of the above-describe type can be associated with a synthetic plate in order to form a cerclage system that allows firmly and effectively retaining said plate against the fractured bone, without any risk for the patient.

Brief Description of the Drawings

Further characteristics and advantages of the invention will be clearer to the man skilled in the art starting from the following detailed description of several preferred embodiments of the invention, given as a non-limiting example with reference to the enclosed drawings, in which:

- Figures 1A and IB illustrate cerclage systems for fractured bones of known type;

- Figure 2 represents a cerclage device for fractured bones according to a first preferred embodiment of the invention;

- Figures 3A and 3B illustrate in detail a spacer of the cerclage device of Figure 2;

- Figure 4 represents a spacer of a cerclage device for fractured bones according to a second preferred embodiment of the invention;

- Figure 5 represents a spacer of a cerclage device for fractured bones according to a third preferred embodiment of the invention;

- Figure 6 represents a spacer of a cerclage device for fractured bones according to a fourth preferred embodiment of the invention.

Description of Some Preferred Embodiments

With reference to Figures 2, 3A and 3, the following are illustrated: a device 1 for the cerclage of fractured bones according to a first preferred embodiment of the invention and a spacer 5 of said cerclage device.

The cerclage device 1 comprises a wire 3 and a plurality of spacers 5 arranged on said wire 3, and said spacers 5 allow maintaining the wire 3 at a certain distance from the bone to which the cerclage device 1 is applied once the wire 3 is tightened and locked on said bone.

In order to insert the spacers 5 on the wire 3, said spacers provide for a through hole 7 for the passage of said wire therethrough. Said hole 7 has a diameter slightly larger than the diameter of the wire 3, such that the spacers 5 are free to slide along said wire.

In order to fix the spacers 5 in the desired position, the cerclage device 1 also comprises locking means adapted to allow / prevent the sliding of said spacers with respect to the wire 3.

In the embodiment illustrated in Figures 3A and 3B, each spacer 5 is provided with a hole 9, preferably conical, suitable for receiving a screw or a pin (not illustrated) , also preferably correspondingly conical. Such screw or pin can penetrate into said hole 9 until it presses against the wire 3 and exerts on said wire a pressure sufficient to prevent any further sliding of said spacer with respect to said wire, thus obtaining the locking function.

It is clear that such locking means are easily reversible.

According to the invention, the cerclage device 1 also comprises a safety wire or thread 11 that passes through the spacers 9 and keeps them connected to each other in case of breakage of the cerclage wire 3. In the embodiment of Figure 2, only one safety wire or thread 11 is provided for, and for such purpose the spacers 5 provide for an additional through hole 13 for the passage of said safety wire or thread therethrough. In the illustrated example, said additional through hole 13 is parallel to the through hole 7 and suitably spaced therefrom.

Said additional through hole 13 has a diameter slightly larger than the diameter of the safety wire or thread 11, such that said safety wire or thread is not subjected to any friction or rubbing and therefore it is not subject to wear. Advantageously, moreover, the safety wire or thread 11 has a length such to be mounted loose between the spacers 5, so as to not be subjected to any stress during the use of the cerclage device 1.

Said safety wire or thread 11 is provided at the ends with stop elements 15, suitably sized with respect to the diameter of the through holes 13 of the spacers 5 in order to prevent the unstringing of said spacers from said safety wire or thread .

All elements of the cerclage device 1 are made of materials adapted for the intended surgical use.

In particular, the cerclage wire 3 and the spacers 5 will be made of a material - plastic or metal - that is sufficiently strong to support the stresses to which the cerclage device 1 is subjected once the wire 3 is tightened around the bone. In particular, said wire and said spacers are preferably made of titanium .

The safety wire or thread 11 is instead preferably made of nylon .

In the illustrated embodiment, the spacers 5 are illustrated as cylinders. It is clear that the invention is not limited to spacers of cylindrical shape, but that said spacers can have any one shape, so long as it is able to maintain the wire 3 at a certain distance from the bone to which the device 1 is applied. Generally, however, spacers with rounded external surfaces are preferable, since they prevent damaging the surface of the bone itself.

In a known manner, a plurality of cerclage devices of the above-described type can be associated with a synthetic plate in order to form a cerclage system that allows firmly and effectively retaining said plate against the fractured bone, without any risk for the patient.

In Figure 4, a spacer 5' is illustrated of a cerclage device according to a second embodiment of the invention.

In this second embodiment of the invention, two safety wires or threads are provided, and for such purpose the spacer 5' comprises two additional through holes 13' , each provided for the passage of a respective safety wire or thread.

In the illustrated embodiment, said additional through holes 13' are both parallel to the through hole 7' and are provided aligned with each other at opposite sides of said through hole 7', even if it is clear that any alternative arrange could be equally acceptable.

In Figure 5, a spacer 5' ' is illustrated of a cerclage device according to a third embodiment of the invention, which provides for the presence of a single safety wire or thread. In this third embodiment of the invention, the spacer 5'' comprises an additional through hole 13' ' for the passage of said safety wire or thread, said through hole 13' ' being provided perpendicular to the through hole 1'' for the passage of the cerclage wire.

Said additional through hole 13' ' is suitably offset, in a manner so as to not interfere with the passage of said cerclage wire.

Of course, it is also possible to provide for embodiments that provide additional safety wires or threads and spacers provided with a corresponding number of additional through holes perpendicular to the through hole for the passage of the cerclage wire and parallel to each other.

It is also possible to provide that the additional through hole or the additional through holes is / are in any case tilted with respect to said through hole for the passage of the cerclage wire.

In Figure 6, a spacer 25 is illustrated of a cerclage device according to a fourth embodiment of the invention.

In this fourth embodiment of the invention, the spacer 25 has spherical rather than cylindrical shape and comprises a through hole 27 for the passage of the cerclage wire and an additional through hole 33, parallel to said through hole 27 and offset with respect thereto, for the passage of said safety wire or thread. The spacer 25 also comprises a region 29 in which the surface portion of the spherical spacer 25 volume is removed, said region 29 being intended for the punching of the spacer itself in order to crimp the cerclage wire and thus prevent any further sliding of said spacer with respect to said wire.

Overall, it is clear that the preceding detailed description was given as a hliiiilimiting example and that numerous variants and modifications are possible without departing from the protective scope of the invention as defined by the claims set.

In particular, ample degrees of freedom are provided for in the selection of materials, in the number and shape of the spacers, in the nature of the locking means for said spacers, in the number and in the arrangement of the additional through holes for the passage of the safety wires or threads and in the number of the latter.

In addition, even if the embodiments illustrated make reference to a device comprising a cerclage wire, it is clear that said wire could be substituted by a cerclage thread.

Claims

1. Device (1) for the cerclage of a fractured bone, comprising a cerclage wire or thread (3) suitable for being tightened and locked around said bone, a plurality of spacers (5; 5' ; 5' ' ; 25) , arranged on said cerclage wire or thread (3) for keeping said cerclage wire or thread (3) at a certain distance from said bone and slidable on said cerclage wire or thread and locking means suitable for allowing / preventing the sliding of said spacers (5; 5' ; 5' ' ; 25) with respect to said cerclage wire or thread (3) , characterized in that it further comprises one or more safety wires or threads (11) which connect said spacers (5; 5' ; 5' ' ; 25) to each other and which are sized in a manner so as to be mounted loose between said spacers (5; 5' ; 5' ' ; 25) .

2. Device (1) according to claim 1, wherein said spacers (5; 5' ; 5' ' ; 25) provide for a through hole (7 ; 7 ' ; 7 ' ' ; 27 ) for the passage of said cerclage wire or thread (3) therethrough, said through hole (7 ; 7 ' ; 7 ' ' ; 27 ) having a diameter slightly larger than the diameter of said cerclage wire or thread (3) .

3. Device (1) according to claim 2, wherein said spacers (5; 5' ; 5' ' ; 25) provide for one or more additional through holes (13; 13' ; 13' ' ; 33) for the passage of respective safety wires or threads (11) therethrough, said additional through holes (13; 13' ; 13' ' ; 33) having a diameter slightly larger than the diameter of said safety wires or threads (11) .

4. Device (1) according to claim 3, wherein said one or more additional through holes (13; 13'; 33) for the passage of said safety wires or threads are parallel to said through hole (7;7';27) for the passage of said cerclage wire or thread.

5. Device (1) according to claim 4, wherein two said additional through holes (13') for the passage of said safety wires or threads are provided and such holes are aligned with each other at opposite sides of said through hole (7') for the passage of said cerclage wire or thread.

6. Device (1) according to claim 3, wherein said one or more additional through holes (13'') for the passage of said safety wires or threads are perpendicular to said through hole (7'') for the passage of said cerclage wire or thread.

7. Device (1) according to any of the preceding claims, wherein said one or more safety wires or threads (11) are provided at each end with stop elements (15) suitable for preventing the unstringing of said spacers from said safety wires or threads.

8. Device (1) according to any of the preceding claims, wherein said spacers (25) provide for a region (29) in which a surface portion of said spacers is removed, said region (29) being intended for the punching of the spacers themselves.

9. System for the cerclage of a fractured bone, characterized in that it comprises a plate suitable for being abutted against said fractured bone and one or more cerclage devices (1) according to any of the claims 1 to 8 for maintaining said plate firmly coupled to said bone.